190527PX Added zip export to database, set .net version to 4.5

App.config

@@ -2,5 +2,5 @@
 <configuration>
     <startup> 
         
-    <supportedRuntime version="v2.0.50727"/></startup>
+    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup>
 </configuration>

ICSharpCode.SharpZipLib/BZip2/BZip2.cs

@@ -0,0 +1,77 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.BZip2
+{
+	/// <summary>
+	/// An example class to demonstrate compression and decompression of BZip2 streams.
+	/// </summary>
+	public static class BZip2
+	{
+		/// <summary>
+		/// Decompress the <paramref name="inStream">input</paramref> writing
+		/// uncompressed data to the <paramref name="outStream">output stream</paramref>
+		/// </summary>
+		/// <param name="inStream">The readable stream containing data to decompress.</param>
+		/// <param name="outStream">The output stream to receive the decompressed data.</param>
+		/// <param name="isStreamOwner">Both streams are closed on completion if true.</param>
+		public static void Decompress(Stream inStream, Stream outStream, bool isStreamOwner)
+		{
+			if (inStream == null || outStream == null)
+			{
+				throw new Exception("Null Stream");
+			}
+
+			try
+			{
+				using (BZip2InputStream bzipInput = new BZip2InputStream(inStream))
+				{
+					bzipInput.IsStreamOwner = isStreamOwner;
+					Core.StreamUtils.Copy(bzipInput, outStream, new byte[4096]);
+				}
+			}
+			finally
+			{
+				if (isStreamOwner)
+				{
+					// inStream is closed by the BZip2InputStream if stream owner
+					outStream.Dispose();
+				}
+			}
+		}
+
+		/// <summary>
+		/// Compress the <paramref name="inStream">input stream</paramref> sending
+		/// result data to <paramref name="outStream">output stream</paramref>
+		/// </summary>
+		/// <param name="inStream">The readable stream to compress.</param>
+		/// <param name="outStream">The output stream to receive the compressed data.</param>
+		/// <param name="isStreamOwner">Both streams are closed on completion if true.</param>
+		/// <param name="level">Block size acts as compression level (1 to 9) with 1 giving
+		/// the lowest compression and 9 the highest.</param>
+		public static void Compress(Stream inStream, Stream outStream, bool isStreamOwner, int level)
+		{
+			if (inStream == null || outStream == null)
+			{
+				throw new Exception("Null Stream");
+			}
+
+			try
+			{
+				using (BZip2OutputStream bzipOutput = new BZip2OutputStream(outStream, level))
+				{
+					bzipOutput.IsStreamOwner = isStreamOwner;
+					Core.StreamUtils.Copy(inStream, bzipOutput, new byte[4096]);
+				}
+			}
+			finally
+			{
+				if (isStreamOwner)
+				{
+					// outStream is closed by the BZip2OutputStream if stream owner
+					inStream.Dispose();
+				}
+			}
+		}
+	}
+}

ICSharpCode.SharpZipLib/BZip2/BZip2Constants.cs

@@ -0,0 +1,121 @@
+namespace ICSharpCode.SharpZipLib.BZip2
+{
+	/// <summary>
+	/// Defines internal values for both compression and decompression
+	/// </summary>
+	internal sealed class BZip2Constants
+	{
+		/// <summary>
+		/// Random numbers used to randomise repetitive blocks
+		/// </summary>
+		public readonly static int[] RandomNumbers = {
+			619, 720, 127, 481, 931, 816, 813, 233, 566, 247,
+			985, 724, 205, 454, 863, 491, 741, 242, 949, 214,
+			733, 859, 335, 708, 621, 574,  73, 654, 730, 472,
+			419, 436, 278, 496, 867, 210, 399, 680, 480,  51,
+			878, 465, 811, 169, 869, 675, 611, 697, 867, 561,
+			862, 687, 507, 283, 482, 129, 807, 591, 733, 623,
+			150, 238,  59, 379, 684, 877, 625, 169, 643, 105,
+			170, 607, 520, 932, 727, 476, 693, 425, 174, 647,
+			 73, 122, 335, 530, 442, 853, 695, 249, 445, 515,
+			909, 545, 703, 919, 874, 474, 882, 500, 594, 612,
+			641, 801, 220, 162, 819, 984, 589, 513, 495, 799,
+			161, 604, 958, 533, 221, 400, 386, 867, 600, 782,
+			382, 596, 414, 171, 516, 375, 682, 485, 911, 276,
+			 98, 553, 163, 354, 666, 933, 424, 341, 533, 870,
+			227, 730, 475, 186, 263, 647, 537, 686, 600, 224,
+			469,  68, 770, 919, 190, 373, 294, 822, 808, 206,
+			184, 943, 795, 384, 383, 461, 404, 758, 839, 887,
+			715,  67, 618, 276, 204, 918, 873, 777, 604, 560,
+			951, 160, 578, 722,  79, 804,  96, 409, 713, 940,
+			652, 934, 970, 447, 318, 353, 859, 672, 112, 785,
+			645, 863, 803, 350, 139,  93, 354,  99, 820, 908,
+			609, 772, 154, 274, 580, 184,  79, 626, 630, 742,
+			653, 282, 762, 623, 680,  81, 927, 626, 789, 125,
+			411, 521, 938, 300, 821,  78, 343, 175, 128, 250,
+			170, 774, 972, 275, 999, 639, 495,  78, 352, 126,
+			857, 956, 358, 619, 580, 124, 737, 594, 701, 612,
+			669, 112, 134, 694, 363, 992, 809, 743, 168, 974,
+			944, 375, 748,  52, 600, 747, 642, 182, 862,  81,
+			344, 805, 988, 739, 511, 655, 814, 334, 249, 515,
+			897, 955, 664, 981, 649, 113, 974, 459, 893, 228,
+			433, 837, 553, 268, 926, 240, 102, 654, 459,  51,
+			686, 754, 806, 760, 493, 403, 415, 394, 687, 700,
+			946, 670, 656, 610, 738, 392, 760, 799, 887, 653,
+			978, 321, 576, 617, 626, 502, 894, 679, 243, 440,
+			680, 879, 194, 572, 640, 724, 926,  56, 204, 700,
+			707, 151, 457, 449, 797, 195, 791, 558, 945, 679,
+			297,  59,  87, 824, 713, 663, 412, 693, 342, 606,
+			134, 108, 571, 364, 631, 212, 174, 643, 304, 329,
+			343,  97, 430, 751, 497, 314, 983, 374, 822, 928,
+			140, 206,  73, 263, 980, 736, 876, 478, 430, 305,
+			170, 514, 364, 692, 829,  82, 855, 953, 676, 246,
+			369, 970, 294, 750, 807, 827, 150, 790, 288, 923,
+			804, 378, 215, 828, 592, 281, 565, 555, 710,  82,
+			896, 831, 547, 261, 524, 462, 293, 465, 502,  56,
+			661, 821, 976, 991, 658, 869, 905, 758, 745, 193,
+			768, 550, 608, 933, 378, 286, 215, 979, 792, 961,
+			 61, 688, 793, 644, 986, 403, 106, 366, 905, 644,
+			372, 567, 466, 434, 645, 210, 389, 550, 919, 135,
+			780, 773, 635, 389, 707, 100, 626, 958, 165, 504,
+			920, 176, 193, 713, 857, 265, 203,  50, 668, 108,
+			645, 990, 626, 197, 510, 357, 358, 850, 858, 364,
+			936, 638
+		};
+
+		/// <summary>
+		/// When multiplied by compression parameter (1-9) gives the block size for compression
+		/// 9 gives the best compression but uses the most memory.
+		/// </summary>
+		public const int BaseBlockSize = 100000;
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int MaximumAlphaSize = 258;
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int MaximumCodeLength = 23;
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int RunA = 0;
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int RunB = 1;
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int GroupCount = 6;
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int GroupSize = 50;
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int NumberOfIterations = 4;
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int MaximumSelectors = (2 + (900000 / GroupSize));
+
+		/// <summary>
+		/// Backend constant
+		/// </summary>
+		public const int OvershootBytes = 20;
+
+		private BZip2Constants()
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/BZip2/BZip2Exception.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.BZip2
+{
+	/// <summary>
+	/// BZip2Exception represents exceptions specific to BZip2 classes and code.
+	/// </summary>
+	public class BZip2Exception : SharpZipBaseException
+	{
+		/// <summary>
+		/// Initialise a new instance of <see cref="BZip2Exception" />.
+		/// </summary>
+		public BZip2Exception()
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="BZip2Exception" /> with its message string.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		public BZip2Exception(string message)
+			: base(message)
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="BZip2Exception" />.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		/// <param name="innerException">The <see cref="Exception"/> that caused this exception.</param>
+		public BZip2Exception(string message, Exception innerException)
+			: base(message, innerException)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Checksum/Adler32.cs

@@ -0,0 +1,163 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Checksum
+{
+	/// <summary>
+	/// Computes Adler32 checksum for a stream of data. An Adler32
+	/// checksum is not as reliable as a CRC32 checksum, but a lot faster to
+	/// compute.
+	///
+	/// The specification for Adler32 may be found in RFC 1950.
+	/// ZLIB Compressed Data Format Specification version 3.3)
+	///
+	///
+	/// From that document:
+	///
+	///      "ADLER32 (Adler-32 checksum)
+	///       This contains a checksum value of the uncompressed data
+	///       (excluding any dictionary data) computed according to Adler-32
+	///       algorithm. This algorithm is a 32-bit extension and improvement
+	///       of the Fletcher algorithm, used in the ITU-T X.224 / ISO 8073
+	///       standard.
+	///
+	///       Adler-32 is composed of two sums accumulated per byte: s1 is
+	///       the sum of all bytes, s2 is the sum of all s1 values. Both sums
+	///       are done modulo 65521. s1 is initialized to 1, s2 to zero.  The
+	///       Adler-32 checksum is stored as s2*65536 + s1 in most-
+	///       significant-byte first (network) order."
+	///
+	///  "8.2. The Adler-32 algorithm
+	///
+	///    The Adler-32 algorithm is much faster than the CRC32 algorithm yet
+	///    still provides an extremely low probability of undetected errors.
+	///
+	///    The modulo on unsigned long accumulators can be delayed for 5552
+	///    bytes, so the modulo operation time is negligible.  If the bytes
+	///    are a, b, c, the second sum is 3a + 2b + c + 3, and so is position
+	///    and order sensitive, unlike the first sum, which is just a
+	///    checksum.  That 65521 is prime is important to avoid a possible
+	///    large class of two-byte errors that leave the check unchanged.
+	///    (The Fletcher checksum uses 255, which is not prime and which also
+	///    makes the Fletcher check insensitive to single byte changes 0 -
+	///    255.)
+	///
+	///    The sum s1 is initialized to 1 instead of zero to make the length
+	///    of the sequence part of s2, so that the length does not have to be
+	///    checked separately. (Any sequence of zeroes has a Fletcher
+	///    checksum of zero.)"
+	/// </summary>
+	/// <see cref="ICSharpCode.SharpZipLib.Zip.Compression.Streams.InflaterInputStream"/>
+	/// <see cref="ICSharpCode.SharpZipLib.Zip.Compression.Streams.DeflaterOutputStream"/>
+	public sealed class Adler32 : IChecksum
+	{
+		#region Instance Fields
+
+		/// <summary>
+		/// largest prime smaller than 65536
+		/// </summary>
+		private static readonly uint BASE = 65521;
+
+		/// <summary>
+		/// The CRC data checksum so far.
+		/// </summary>
+		private uint checkValue;
+
+		#endregion Instance Fields
+
+		/// <summary>
+		/// Initialise a default instance of <see cref="Adler32"></see>
+		/// </summary>
+		public Adler32()
+		{
+			Reset();
+		}
+
+		/// <summary>
+		/// Resets the Adler32 data checksum as if no update was ever called.
+		/// </summary>
+		public void Reset()
+		{
+			checkValue = 1;
+		}
+
+		/// <summary>
+		/// Returns the Adler32 data checksum computed so far.
+		/// </summary>
+		public long Value
+		{
+			get
+			{
+				return checkValue;
+			}
+		}
+
+		/// <summary>
+		/// Updates the checksum with the byte b.
+		/// </summary>
+		/// <param name="bval">
+		/// The data value to add. The high byte of the int is ignored.
+		/// </param>
+		public void Update(int bval)
+		{
+			// We could make a length 1 byte array and call update again, but I
+			// would rather not have that overhead
+			uint s1 = checkValue & 0xFFFF;
+			uint s2 = checkValue >> 16;
+
+			s1 = (s1 + ((uint)bval & 0xFF)) % BASE;
+			s2 = (s1 + s2) % BASE;
+
+			checkValue = (s2 << 16) + s1;
+		}
+
+		/// <summary>
+		/// Updates the Adler32 data checksum with the bytes taken from
+		/// a block of data.
+		/// </summary>
+		/// <param name="buffer">Contains the data to update the checksum with.</param>
+		public void Update(byte[] buffer)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			Update(new ArraySegment<byte>(buffer, 0, buffer.Length));
+		}
+
+		/// <summary>
+		/// Update Adler32 data checksum based on a portion of a block of data
+		/// </summary>
+		/// <param name = "segment">
+		/// The chunk of data to add
+		/// </param>
+		public void Update(ArraySegment<byte> segment)
+		{
+			//(By Per Bothner)
+			uint s1 = checkValue & 0xFFFF;
+			uint s2 = checkValue >> 16;
+			var count = segment.Count;
+			var offset = segment.Offset;
+			while (count > 0)
+			{
+				// We can defer the modulo operation:
+				// s1 maximally grows from 65521 to 65521 + 255 * 3800
+				// s2 maximally grows by 3800 * median(s1) = 2090079800 < 2^31
+				int n = 3800;
+				if (n > count)
+				{
+					n = count;
+				}
+				count -= n;
+				while (--n >= 0)
+				{
+					s1 = s1 + (uint)(segment.Array[offset++] & 0xff);
+					s2 = s2 + s1;
+				}
+				s1 %= BASE;
+				s2 %= BASE;
+			}
+			checkValue = (s2 << 16) | s1;
+		}
+	}
+}

ICSharpCode.SharpZipLib/Checksum/BZip2Crc.cs

@@ -0,0 +1,187 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Checksum
+{
+	/// <summary>
+	/// CRC-32 with unreversed data and reversed output
+	/// </summary>
+	/// <remarks>
+	/// Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
+	/// x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0.
+	///
+	/// Polynomials over GF(2) are represented in binary, one bit per coefficient,
+	/// with the lowest powers in the most significant bit.  Then adding polynomials
+	/// is just exclusive-or, and multiplying a polynomial by x is a right shift by
+	/// one.  If we call the above polynomial p, and represent a byte as the
+	/// polynomial q, also with the lowest power in the most significant bit (so the
+	/// byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
+	/// where a mod b means the remainder after dividing a by b.
+	///
+	/// This calculation is done using the shift-register method of multiplying and
+	/// taking the remainder.  The register is initialized to zero, and for each
+	/// incoming bit, x^32 is added mod p to the register if the bit is a one (where
+	/// x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
+	/// x (which is shifting right by one and adding x^32 mod p if the bit shifted
+	/// out is a one).  We start with the highest power (least significant bit) of
+	/// q and repeat for all eight bits of q.
+	///
+	/// The table is simply the CRC of all possible eight bit values.  This is all
+	/// the information needed to generate CRC's on data a byte at a time for all
+	/// combinations of CRC register values and incoming bytes.
+	/// </remarks>
+	public sealed class BZip2Crc : IChecksum
+	{
+		#region Instance Fields
+
+		private const uint crcInit = 0xFFFFFFFF;
+		//const uint crcXor = 0x00000000;
+
+		private static readonly uint[] crcTable = {
+			0X00000000, 0X04C11DB7, 0X09823B6E, 0X0D4326D9,
+			0X130476DC, 0X17C56B6B, 0X1A864DB2, 0X1E475005,
+			0X2608EDB8, 0X22C9F00F, 0X2F8AD6D6, 0X2B4BCB61,
+			0X350C9B64, 0X31CD86D3, 0X3C8EA00A, 0X384FBDBD,
+			0X4C11DB70, 0X48D0C6C7, 0X4593E01E, 0X4152FDA9,
+			0X5F15ADAC, 0X5BD4B01B, 0X569796C2, 0X52568B75,
+			0X6A1936C8, 0X6ED82B7F, 0X639B0DA6, 0X675A1011,
+			0X791D4014, 0X7DDC5DA3, 0X709F7B7A, 0X745E66CD,
+			0X9823B6E0, 0X9CE2AB57, 0X91A18D8E, 0X95609039,
+			0X8B27C03C, 0X8FE6DD8B, 0X82A5FB52, 0X8664E6E5,
+			0XBE2B5B58, 0XBAEA46EF, 0XB7A96036, 0XB3687D81,
+			0XAD2F2D84, 0XA9EE3033, 0XA4AD16EA, 0XA06C0B5D,
+			0XD4326D90, 0XD0F37027, 0XDDB056FE, 0XD9714B49,
+			0XC7361B4C, 0XC3F706FB, 0XCEB42022, 0XCA753D95,
+			0XF23A8028, 0XF6FB9D9F, 0XFBB8BB46, 0XFF79A6F1,
+			0XE13EF6F4, 0XE5FFEB43, 0XE8BCCD9A, 0XEC7DD02D,
+			0X34867077, 0X30476DC0, 0X3D044B19, 0X39C556AE,
+			0X278206AB, 0X23431B1C, 0X2E003DC5, 0X2AC12072,
+			0X128E9DCF, 0X164F8078, 0X1B0CA6A1, 0X1FCDBB16,
+			0X018AEB13, 0X054BF6A4, 0X0808D07D, 0X0CC9CDCA,
+			0X7897AB07, 0X7C56B6B0, 0X71159069, 0X75D48DDE,
+			0X6B93DDDB, 0X6F52C06C, 0X6211E6B5, 0X66D0FB02,
+			0X5E9F46BF, 0X5A5E5B08, 0X571D7DD1, 0X53DC6066,
+			0X4D9B3063, 0X495A2DD4, 0X44190B0D, 0X40D816BA,
+			0XACA5C697, 0XA864DB20, 0XA527FDF9, 0XA1E6E04E,
+			0XBFA1B04B, 0XBB60ADFC, 0XB6238B25, 0XB2E29692,
+			0X8AAD2B2F, 0X8E6C3698, 0X832F1041, 0X87EE0DF6,
+			0X99A95DF3, 0X9D684044, 0X902B669D, 0X94EA7B2A,
+			0XE0B41DE7, 0XE4750050, 0XE9362689, 0XEDF73B3E,
+			0XF3B06B3B, 0XF771768C, 0XFA325055, 0XFEF34DE2,
+			0XC6BCF05F, 0XC27DEDE8, 0XCF3ECB31, 0XCBFFD686,
+			0XD5B88683, 0XD1799B34, 0XDC3ABDED, 0XD8FBA05A,
+			0X690CE0EE, 0X6DCDFD59, 0X608EDB80, 0X644FC637,
+			0X7A089632, 0X7EC98B85, 0X738AAD5C, 0X774BB0EB,
+			0X4F040D56, 0X4BC510E1, 0X46863638, 0X42472B8F,
+			0X5C007B8A, 0X58C1663D, 0X558240E4, 0X51435D53,
+			0X251D3B9E, 0X21DC2629, 0X2C9F00F0, 0X285E1D47,
+			0X36194D42, 0X32D850F5, 0X3F9B762C, 0X3B5A6B9B,
+			0X0315D626, 0X07D4CB91, 0X0A97ED48, 0X0E56F0FF,
+			0X1011A0FA, 0X14D0BD4D, 0X19939B94, 0X1D528623,
+			0XF12F560E, 0XF5EE4BB9, 0XF8AD6D60, 0XFC6C70D7,
+			0XE22B20D2, 0XE6EA3D65, 0XEBA91BBC, 0XEF68060B,
+			0XD727BBB6, 0XD3E6A601, 0XDEA580D8, 0XDA649D6F,
+			0XC423CD6A, 0XC0E2D0DD, 0XCDA1F604, 0XC960EBB3,
+			0XBD3E8D7E, 0XB9FF90C9, 0XB4BCB610, 0XB07DABA7,
+			0XAE3AFBA2, 0XAAFBE615, 0XA7B8C0CC, 0XA379DD7B,
+			0X9B3660C6, 0X9FF77D71, 0X92B45BA8, 0X9675461F,
+			0X8832161A, 0X8CF30BAD, 0X81B02D74, 0X857130C3,
+			0X5D8A9099, 0X594B8D2E, 0X5408ABF7, 0X50C9B640,
+			0X4E8EE645, 0X4A4FFBF2, 0X470CDD2B, 0X43CDC09C,
+			0X7B827D21, 0X7F436096, 0X7200464F, 0X76C15BF8,
+			0X68860BFD, 0X6C47164A, 0X61043093, 0X65C52D24,
+			0X119B4BE9, 0X155A565E, 0X18197087, 0X1CD86D30,
+			0X029F3D35, 0X065E2082, 0X0B1D065B, 0X0FDC1BEC,
+			0X3793A651, 0X3352BBE6, 0X3E119D3F, 0X3AD08088,
+			0X2497D08D, 0X2056CD3A, 0X2D15EBE3, 0X29D4F654,
+			0XC5A92679, 0XC1683BCE, 0XCC2B1D17, 0XC8EA00A0,
+			0XD6AD50A5, 0XD26C4D12, 0XDF2F6BCB, 0XDBEE767C,
+			0XE3A1CBC1, 0XE760D676, 0XEA23F0AF, 0XEEE2ED18,
+			0XF0A5BD1D, 0XF464A0AA, 0XF9278673, 0XFDE69BC4,
+			0X89B8FD09, 0X8D79E0BE, 0X803AC667, 0X84FBDBD0,
+			0X9ABC8BD5, 0X9E7D9662, 0X933EB0BB, 0X97FFAD0C,
+			0XAFB010B1, 0XAB710D06, 0XA6322BDF, 0XA2F33668,
+			0XBCB4666D, 0XB8757BDA, 0XB5365D03, 0XB1F740B4
+		};
+
+		/// <summary>
+		/// The CRC data checksum so far.
+		/// </summary>
+		private uint checkValue;
+
+		#endregion Instance Fields
+
+		/// <summary>
+		/// Initialise a default instance of <see cref="BZip2Crc"></see>
+		/// </summary>
+		public BZip2Crc()
+		{
+			Reset();
+		}
+
+		/// <summary>
+		/// Resets the CRC data checksum as if no update was ever called.
+		/// </summary>
+		public void Reset()
+		{
+			checkValue = crcInit;
+		}
+
+		/// <summary>
+		/// Returns the CRC data checksum computed so far.
+		/// </summary>
+		/// <remarks>Reversed Out = true</remarks>
+		public long Value
+		{
+			get
+			{
+				// Tehcnically, the output should be:
+				//return (long)(~checkValue ^ crcXor);
+				// but x ^ 0 = x, so there is no point in adding
+				// the XOR operation
+				return (long)(~checkValue);
+			}
+		}
+
+		/// <summary>
+		/// Updates the checksum with the int bval.
+		/// </summary>
+		/// <param name = "bval">
+		/// the byte is taken as the lower 8 bits of bval
+		/// </param>
+		/// <remarks>Reversed Data = false</remarks>
+		public void Update(int bval)
+		{
+			checkValue = unchecked(crcTable[(byte)(((checkValue >> 24) & 0xFF) ^ bval)] ^ (checkValue << 8));
+		}
+
+		/// <summary>
+		/// Updates the CRC data checksum with the bytes taken from
+		/// a block of data.
+		/// </summary>
+		/// <param name="buffer">Contains the data to update the CRC with.</param>
+		public void Update(byte[] buffer)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			Update(new ArraySegment<byte>(buffer, 0, buffer.Length));
+		}
+
+		/// <summary>
+		/// Update CRC data checksum based on a portion of a block of data
+		/// </summary>
+		/// <param name = "segment">
+		/// The chunk of data to add
+		/// </param>
+		public void Update(ArraySegment<byte> segment)
+		{
+			var count = segment.Count;
+			var offset = segment.Offset;
+
+			while (--count >= 0)
+				Update(segment.Array[offset++]);
+		}
+	}
+}

ICSharpCode.SharpZipLib/Checksum/Crc32.cs

@@ -0,0 +1,176 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Checksum
+{
+	/// <summary>
+	/// CRC-32 with reversed data and unreversed output
+	/// </summary>
+	/// <remarks>
+	/// Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
+	/// x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0.
+	///
+	/// Polynomials over GF(2) are represented in binary, one bit per coefficient,
+	/// with the lowest powers in the most significant bit.  Then adding polynomials
+	/// is just exclusive-or, and multiplying a polynomial by x is a right shift by
+	/// one.  If we call the above polynomial p, and represent a byte as the
+	/// polynomial q, also with the lowest power in the most significant bit (so the
+	/// byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
+	/// where a mod b means the remainder after dividing a by b.
+	///
+	/// This calculation is done using the shift-register method of multiplying and
+	/// taking the remainder.  The register is initialized to zero, and for each
+	/// incoming bit, x^32 is added mod p to the register if the bit is a one (where
+	/// x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
+	/// x (which is shifting right by one and adding x^32 mod p if the bit shifted
+	/// out is a one).  We start with the highest power (least significant bit) of
+	/// q and repeat for all eight bits of q.
+	///
+	/// The table is simply the CRC of all possible eight bit values.  This is all
+	/// the information needed to generate CRC's on data a byte at a time for all
+	/// combinations of CRC register values and incoming bytes.
+	/// </remarks>
+	public sealed class Crc32 : IChecksum
+	{
+		#region Instance Fields
+
+		private static readonly uint crcInit = 0xFFFFFFFF;
+		private static readonly uint crcXor = 0xFFFFFFFF;
+
+		private static readonly uint[] crcTable = {
+			0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419,
+			0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4,
+			0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07,
+			0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
+			0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856,
+			0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
+			0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
+			0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
+			0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3,
+			0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A,
+			0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599,
+			0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
+			0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190,
+			0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
+			0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E,
+			0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
+			0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED,
+			0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
+			0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3,
+			0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
+			0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A,
+			0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5,
+			0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010,
+			0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
+			0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17,
+			0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6,
+			0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615,
+			0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
+			0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344,
+			0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
+			0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A,
+			0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
+			0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1,
+			0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
+			0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF,
+			0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
+			0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE,
+			0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31,
+			0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C,
+			0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
+			0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B,
+			0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
+			0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1,
+			0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
+			0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278,
+			0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7,
+			0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66,
+			0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
+			0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605,
+			0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8,
+			0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B,
+			0x2D02EF8D
+		};
+
+		/// <summary>
+		/// The CRC data checksum so far.
+		/// </summary>
+		private uint checkValue;
+
+		#endregion Instance Fields
+
+		internal static uint ComputeCrc32(uint oldCrc, byte bval)
+		{
+			return (uint)(Crc32.crcTable[(oldCrc ^ bval) & 0xFF] ^ (oldCrc >> 8));
+		}
+
+		/// <summary>
+		/// Initialise a default instance of <see cref="Crc32"></see>
+		/// </summary>
+		public Crc32()
+		{
+			Reset();
+		}
+
+		/// <summary>
+		/// Resets the CRC data checksum as if no update was ever called.
+		/// </summary>
+		public void Reset()
+		{
+			checkValue = crcInit;
+		}
+
+		/// <summary>
+		/// Returns the CRC data checksum computed so far.
+		/// </summary>
+		/// <remarks>Reversed Out = false</remarks>
+		public long Value
+		{
+			get
+			{
+				return (long)(checkValue ^ crcXor);
+			}
+		}
+
+		/// <summary>
+		/// Updates the checksum with the int bval.
+		/// </summary>
+		/// <param name = "bval">
+		/// the byte is taken as the lower 8 bits of bval
+		/// </param>
+		/// <remarks>Reversed Data = true</remarks>
+		public void Update(int bval)
+		{
+			checkValue = unchecked(crcTable[(checkValue ^ bval) & 0xFF] ^ (checkValue >> 8));
+		}
+
+		/// <summary>
+		/// Updates the CRC data checksum with the bytes taken from
+		/// a block of data.
+		/// </summary>
+		/// <param name="buffer">Contains the data to update the CRC with.</param>
+		public void Update(byte[] buffer)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			Update(new ArraySegment<byte>(buffer, 0, buffer.Length));
+		}
+
+		/// <summary>
+		/// Update CRC data checksum based on a portion of a block of data
+		/// </summary>
+		/// <param name = "segment">
+		/// The chunk of data to add
+		/// </param>
+		public void Update(ArraySegment<byte> segment)
+		{
+			var count = segment.Count;
+			var offset = segment.Offset;
+
+			while (--count >= 0)
+				Update(segment.Array[offset++]);
+		}
+	}
+}

ICSharpCode.SharpZipLib/Checksum/IChecksum.cs

@@ -0,0 +1,51 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Checksum
+{
+	/// <summary>
+	/// Interface to compute a data checksum used by checked input/output streams.
+	/// A data checksum can be updated by one byte or with a byte array. After each
+	/// update the value of the current checksum can be returned by calling
+	/// <code>getValue</code>. The complete checksum object can also be reset
+	/// so it can be used again with new data.
+	/// </summary>
+	public interface IChecksum
+	{
+		/// <summary>
+		/// Resets the data checksum as if no update was ever called.
+		/// </summary>
+		void Reset();
+
+		/// <summary>
+		/// Returns the data checksum computed so far.
+		/// </summary>
+		long Value
+		{
+			get;
+		}
+
+		/// <summary>
+		/// Adds one byte to the data checksum.
+		/// </summary>
+		/// <param name = "bval">
+		/// the data value to add. The high byte of the int is ignored.
+		/// </param>
+		void Update(int bval);
+
+		/// <summary>
+		/// Updates the data checksum with the bytes taken from the array.
+		/// </summary>
+		/// <param name="buffer">
+		/// buffer an array of bytes
+		/// </param>
+		void Update(byte[] buffer);
+
+		/// <summary>
+		/// Adds the byte array to the data checksum.
+		/// </summary>
+		/// <param name = "segment">
+		/// The chunk of data to add
+		/// </param>
+		void Update(ArraySegment<byte> segment);
+	}
+}

ICSharpCode.SharpZipLib/Core/Exceptions/SharpZipBaseException.cs

@@ -0,0 +1,40 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib
+{
+	/// <summary>
+	/// SharpZipBaseException is the base exception class for SharpZipLib.
+	/// All library exceptions are derived from this.
+	/// </summary>
+	/// <remarks>NOTE: Not all exceptions thrown will be derived from this class.
+	/// A variety of other exceptions are possible for example <see cref="ArgumentNullException"></see></remarks>
+	public class SharpZipBaseException : Exception
+	{
+		/// <summary>
+		/// Initializes a new instance of the SharpZipBaseException class.
+		/// </summary>
+		public SharpZipBaseException()
+		{
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the SharpZipBaseException class with a specified error message.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		public SharpZipBaseException(string message)
+			: base(message)
+		{
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the SharpZipBaseException class with a specified
+		/// error message and a reference to the inner exception that is the cause of this exception.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		/// <param name="innerException">The inner exception</param>
+		public SharpZipBaseException(string message, Exception innerException)
+			: base(message, innerException)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Core/Exceptions/StreamDecodingException.cs

@@ -0,0 +1,32 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib
+{
+	/// <summary>
+	/// Indicates that an error occured during decoding of a input stream due to corrupt
+	/// data or (unintentional) library incompability.
+	/// </summary>
+	public class StreamDecodingException : SharpZipBaseException
+	{
+		private const string GenericMessage = "Input stream could not be decoded";
+
+		/// <summary>
+		/// Initializes a new instance of the StreamDecodingException with a generic message
+		/// </summary>
+		public StreamDecodingException() : base(GenericMessage) { }
+
+		/// <summary>
+		/// Initializes a new instance of the StreamDecodingException class with a specified error message.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		public StreamDecodingException(string message) : base(message) { }
+
+		/// <summary>
+		/// Initializes a new instance of the StreamDecodingException class with a specified
+		/// error message and a reference to the inner exception that is the cause of this exception.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		/// <param name="innerException">The inner exception</param>
+		public StreamDecodingException(string message, Exception innerException) : base(message, innerException) { }
+	}
+}

ICSharpCode.SharpZipLib/Core/Exceptions/StreamUnsupportedException.cs

@@ -0,0 +1,31 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib
+{
+	/// <summary>
+	/// Indicates that the input stream could not decoded due to known library incompability or missing features
+	/// </summary>
+	public class StreamUnsupportedException : StreamDecodingException
+	{
+		private const string GenericMessage = "Input stream is in a unsupported format";
+
+		/// <summary>
+		/// Initializes a new instance of the StreamUnsupportedException with a generic message
+		/// </summary>
+		public StreamUnsupportedException() : base(GenericMessage) { }
+
+		/// <summary>
+		/// Initializes a new instance of the StreamUnsupportedException class with a specified error message.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		public StreamUnsupportedException(string message) : base(message) { }
+
+		/// <summary>
+		/// Initializes a new instance of the StreamUnsupportedException class with a specified
+		/// error message and a reference to the inner exception that is the cause of this exception.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		/// <param name="innerException">The inner exception</param>
+		public StreamUnsupportedException(string message, Exception innerException) : base(message, innerException) { }
+	}
+}

ICSharpCode.SharpZipLib/Core/Exceptions/UnexpectedEndOfStreamException.cs

@@ -0,0 +1,31 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib
+{
+	/// <summary>
+	/// Indicates that the input stream could not decoded due to the stream ending before enough data had been provided
+	/// </summary>
+	public class UnexpectedEndOfStreamException : StreamDecodingException
+	{
+		private const string GenericMessage = "Input stream ended unexpectedly";
+
+		/// <summary>
+		/// Initializes a new instance of the UnexpectedEndOfStreamException with a generic message
+		/// </summary>
+		public UnexpectedEndOfStreamException() : base(GenericMessage) { }
+
+		/// <summary>
+		/// Initializes a new instance of the UnexpectedEndOfStreamException class with a specified error message.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		public UnexpectedEndOfStreamException(string message) : base(message) { }
+
+		/// <summary>
+		/// Initializes a new instance of the UnexpectedEndOfStreamException class with a specified
+		/// error message and a reference to the inner exception that is the cause of this exception.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		/// <param name="innerException">The inner exception</param>
+		public UnexpectedEndOfStreamException(string message, Exception innerException) : base(message, innerException) { }
+	}
+}

ICSharpCode.SharpZipLib/Core/Exceptions/ValueOutOfRangeException.cs

@@ -0,0 +1,48 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib
+{
+	/// <summary>
+	/// Indicates that a value was outside of the expected range when decoding an input stream
+	/// </summary>
+	public class ValueOutOfRangeException : StreamDecodingException
+	{
+		/// <summary>
+		/// Initializes a new instance of the ValueOutOfRangeException class naming the the causing variable
+		/// </summary>
+		/// <param name="nameOfValue">Name of the variable, use: nameof()</param>
+		public ValueOutOfRangeException(string nameOfValue)
+			: base($"{nameOfValue} out of range") { }
+
+		/// <summary>
+		/// Initializes a new instance of the ValueOutOfRangeException class naming the the causing variable,
+		/// it's current value and expected range.
+		/// </summary>
+		/// <param name="nameOfValue">Name of the variable, use: nameof()</param>
+		/// <param name="value">The invalid value</param>
+		/// <param name="maxValue">Expected maximum value</param>
+		/// <param name="minValue">Expected minimum value</param>
+		public ValueOutOfRangeException(string nameOfValue, long value, long maxValue, long minValue = 0)
+			: this(nameOfValue, value.ToString(), maxValue.ToString(), minValue.ToString()) { }
+
+		/// <summary>
+		/// Initializes a new instance of the ValueOutOfRangeException class naming the the causing variable,
+		/// it's current value and expected range.
+		/// </summary>
+		/// <param name="nameOfValue">Name of the variable, use: nameof()</param>
+		/// <param name="value">The invalid value</param>
+		/// <param name="maxValue">Expected maximum value</param>
+		/// <param name="minValue">Expected minimum value</param>
+		public ValueOutOfRangeException(string nameOfValue, string value, string maxValue, string minValue = "0") :
+			base($"{nameOfValue} out of range: {value}, should be {minValue}..{maxValue}")
+		{ }
+
+		private ValueOutOfRangeException()
+		{
+		}
+
+		private ValueOutOfRangeException(string message, Exception innerException) : base(message, innerException)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Core/FileSystemScanner.cs

@@ -0,0 +1,545 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Core
+{
+	#region EventArgs
+
+	/// <summary>
+	/// Event arguments for scanning.
+	/// </summary>
+	public class ScanEventArgs : EventArgs
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="ScanEventArgs"/>
+		/// </summary>
+		/// <param name="name">The file or directory name.</param>
+		public ScanEventArgs(string name)
+		{
+			name_ = name;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// The file or directory name for this event.
+		/// </summary>
+		public string Name
+		{
+			get { return name_; }
+		}
+
+		/// <summary>
+		/// Get set a value indicating if scanning should continue or not.
+		/// </summary>
+		public bool ContinueRunning
+		{
+			get { return continueRunning_; }
+			set { continueRunning_ = value; }
+		}
+
+		#region Instance Fields
+
+		private string name_;
+		private bool continueRunning_ = true;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// Event arguments during processing of a single file or directory.
+	/// </summary>
+	public class ProgressEventArgs : EventArgs
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="ScanEventArgs"/>
+		/// </summary>
+		/// <param name="name">The file or directory name if known.</param>
+		/// <param name="processed">The number of bytes processed so far</param>
+		/// <param name="target">The total number of bytes to process, 0 if not known</param>
+		public ProgressEventArgs(string name, long processed, long target)
+		{
+			name_ = name;
+			processed_ = processed;
+			target_ = target;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// The name for this event if known.
+		/// </summary>
+		public string Name
+		{
+			get { return name_; }
+		}
+
+		/// <summary>
+		/// Get set a value indicating wether scanning should continue or not.
+		/// </summary>
+		public bool ContinueRunning
+		{
+			get { return continueRunning_; }
+			set { continueRunning_ = value; }
+		}
+
+		/// <summary>
+		/// Get a percentage representing how much of the <see cref="Target"></see> has been processed
+		/// </summary>
+		/// <value>0.0 to 100.0 percent; 0 if target is not known.</value>
+		public float PercentComplete
+		{
+			get
+			{
+				float result;
+				if (target_ <= 0)
+				{
+					result = 0;
+				}
+				else
+				{
+					result = ((float)processed_ / (float)target_) * 100.0f;
+				}
+				return result;
+			}
+		}
+
+		/// <summary>
+		/// The number of bytes processed so far
+		/// </summary>
+		public long Processed
+		{
+			get { return processed_; }
+		}
+
+		/// <summary>
+		/// The number of bytes to process.
+		/// </summary>
+		/// <remarks>Target may be 0 or negative if the value isnt known.</remarks>
+		public long Target
+		{
+			get { return target_; }
+		}
+
+		#region Instance Fields
+
+		private string name_;
+		private long processed_;
+		private long target_;
+		private bool continueRunning_ = true;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// Event arguments for directories.
+	/// </summary>
+	public class DirectoryEventArgs : ScanEventArgs
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialize an instance of <see cref="DirectoryEventArgs"></see>.
+		/// </summary>
+		/// <param name="name">The name for this directory.</param>
+		/// <param name="hasMatchingFiles">Flag value indicating if any matching files are contained in this directory.</param>
+		public DirectoryEventArgs(string name, bool hasMatchingFiles)
+			: base(name)
+		{
+			hasMatchingFiles_ = hasMatchingFiles;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Get a value indicating if the directory contains any matching files or not.
+		/// </summary>
+		public bool HasMatchingFiles
+		{
+			get { return hasMatchingFiles_; }
+		}
+
+		private readonly
+
+		#region Instance Fields
+
+		bool hasMatchingFiles_;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// Arguments passed when scan failures are detected.
+	/// </summary>
+	public class ScanFailureEventArgs : EventArgs
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="ScanFailureEventArgs"></see>
+		/// </summary>
+		/// <param name="name">The name to apply.</param>
+		/// <param name="e">The exception to use.</param>
+		public ScanFailureEventArgs(string name, Exception e)
+		{
+			name_ = name;
+			exception_ = e;
+			continueRunning_ = true;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// The applicable name.
+		/// </summary>
+		public string Name
+		{
+			get { return name_; }
+		}
+
+		/// <summary>
+		/// The applicable exception.
+		/// </summary>
+		public Exception Exception
+		{
+			get { return exception_; }
+		}
+
+		/// <summary>
+		/// Get / set a value indicating wether scanning should continue.
+		/// </summary>
+		public bool ContinueRunning
+		{
+			get { return continueRunning_; }
+			set { continueRunning_ = value; }
+		}
+
+		#region Instance Fields
+
+		private string name_;
+		private Exception exception_;
+		private bool continueRunning_;
+
+		#endregion Instance Fields
+	}
+
+	#endregion EventArgs
+
+	#region Delegates
+
+	/// <summary>
+	/// Delegate invoked before starting to process a file.
+	/// </summary>
+	/// <param name="sender">The source of the event</param>
+	/// <param name="e">The event arguments.</param>
+	public delegate void ProcessFileHandler(object sender, ScanEventArgs e);
+
+	/// <summary>
+	/// Delegate invoked during processing of a file or directory
+	/// </summary>
+	/// <param name="sender">The source of the event</param>
+	/// <param name="e">The event arguments.</param>
+	public delegate void ProgressHandler(object sender, ProgressEventArgs e);
+
+	/// <summary>
+	/// Delegate invoked when a file has been completely processed.
+	/// </summary>
+	/// <param name="sender">The source of the event</param>
+	/// <param name="e">The event arguments.</param>
+	public delegate void CompletedFileHandler(object sender, ScanEventArgs e);
+
+	/// <summary>
+	/// Delegate invoked when a directory failure is detected.
+	/// </summary>
+	/// <param name="sender">The source of the event</param>
+	/// <param name="e">The event arguments.</param>
+	public delegate void DirectoryFailureHandler(object sender, ScanFailureEventArgs e);
+
+	/// <summary>
+	/// Delegate invoked when a file failure is detected.
+	/// </summary>
+	/// <param name="sender">The source of the event</param>
+	/// <param name="e">The event arguments.</param>
+	public delegate void FileFailureHandler(object sender, ScanFailureEventArgs e);
+
+	#endregion Delegates
+
+	/// <summary>
+	/// FileSystemScanner provides facilities scanning of files and directories.
+	/// </summary>
+	public class FileSystemScanner
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="FileSystemScanner"></see>
+		/// </summary>
+		/// <param name="filter">The <see cref="PathFilter">file filter</see> to apply when scanning.</param>
+		public FileSystemScanner(string filter)
+		{
+			fileFilter_ = new PathFilter(filter);
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="FileSystemScanner"></see>
+		/// </summary>
+		/// <param name="fileFilter">The <see cref="PathFilter">file filter</see> to apply.</param>
+		/// <param name="directoryFilter">The <see cref="PathFilter"> directory filter</see> to apply.</param>
+		public FileSystemScanner(string fileFilter, string directoryFilter)
+		{
+			fileFilter_ = new PathFilter(fileFilter);
+			directoryFilter_ = new PathFilter(directoryFilter);
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="FileSystemScanner"></see>
+		/// </summary>
+		/// <param name="fileFilter">The file <see cref="IScanFilter">filter</see> to apply.</param>
+		public FileSystemScanner(IScanFilter fileFilter)
+		{
+			fileFilter_ = fileFilter;
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="FileSystemScanner"></see>
+		/// </summary>
+		/// <param name="fileFilter">The file <see cref="IScanFilter">filter</see>  to apply.</param>
+		/// <param name="directoryFilter">The directory <see cref="IScanFilter">filter</see>  to apply.</param>
+		public FileSystemScanner(IScanFilter fileFilter, IScanFilter directoryFilter)
+		{
+			fileFilter_ = fileFilter;
+			directoryFilter_ = directoryFilter;
+		}
+
+		#endregion Constructors
+
+		#region Delegates
+
+		/// <summary>
+		/// Delegate to invoke when a directory is processed.
+		/// </summary>
+		public event EventHandler<DirectoryEventArgs> ProcessDirectory;
+
+		/// <summary>
+		/// Delegate to invoke when a file is processed.
+		/// </summary>
+		public ProcessFileHandler ProcessFile;
+
+		/// <summary>
+		/// Delegate to invoke when processing for a file has finished.
+		/// </summary>
+		public CompletedFileHandler CompletedFile;
+
+		/// <summary>
+		/// Delegate to invoke when a directory failure is detected.
+		/// </summary>
+		public DirectoryFailureHandler DirectoryFailure;
+
+		/// <summary>
+		/// Delegate to invoke when a file failure is detected.
+		/// </summary>
+		public FileFailureHandler FileFailure;
+
+		#endregion Delegates
+
+		/// <summary>
+		/// Raise the DirectoryFailure event.
+		/// </summary>
+		/// <param name="directory">The directory name.</param>
+		/// <param name="e">The exception detected.</param>
+		private bool OnDirectoryFailure(string directory, Exception e)
+		{
+			DirectoryFailureHandler handler = DirectoryFailure;
+			bool result = (handler != null);
+			if (result)
+			{
+				var args = new ScanFailureEventArgs(directory, e);
+				handler(this, args);
+				alive_ = args.ContinueRunning;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Raise the FileFailure event.
+		/// </summary>
+		/// <param name="file">The file name.</param>
+		/// <param name="e">The exception detected.</param>
+		private bool OnFileFailure(string file, Exception e)
+		{
+			FileFailureHandler handler = FileFailure;
+
+			bool result = (handler != null);
+
+			if (result)
+			{
+				var args = new ScanFailureEventArgs(file, e);
+				FileFailure(this, args);
+				alive_ = args.ContinueRunning;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Raise the ProcessFile event.
+		/// </summary>
+		/// <param name="file">The file name.</param>
+		private void OnProcessFile(string file)
+		{
+			ProcessFileHandler handler = ProcessFile;
+
+			if (handler != null)
+			{
+				var args = new ScanEventArgs(file);
+				handler(this, args);
+				alive_ = args.ContinueRunning;
+			}
+		}
+
+		/// <summary>
+		/// Raise the complete file event
+		/// </summary>
+		/// <param name="file">The file name</param>
+		private void OnCompleteFile(string file)
+		{
+			CompletedFileHandler handler = CompletedFile;
+
+			if (handler != null)
+			{
+				var args = new ScanEventArgs(file);
+				handler(this, args);
+				alive_ = args.ContinueRunning;
+			}
+		}
+
+		/// <summary>
+		/// Raise the ProcessDirectory event.
+		/// </summary>
+		/// <param name="directory">The directory name.</param>
+		/// <param name="hasMatchingFiles">Flag indicating if the directory has matching files.</param>
+		private void OnProcessDirectory(string directory, bool hasMatchingFiles)
+		{
+			EventHandler<DirectoryEventArgs> handler = ProcessDirectory;
+
+			if (handler != null)
+			{
+				var args = new DirectoryEventArgs(directory, hasMatchingFiles);
+				handler(this, args);
+				alive_ = args.ContinueRunning;
+			}
+		}
+
+		/// <summary>
+		/// Scan a directory.
+		/// </summary>
+		/// <param name="directory">The base directory to scan.</param>
+		/// <param name="recurse">True to recurse subdirectories, false to scan a single directory.</param>
+		public void Scan(string directory, bool recurse)
+		{
+			alive_ = true;
+			ScanDir(directory, recurse);
+		}
+
+		private void ScanDir(string directory, bool recurse)
+		{
+			try
+			{
+				string[] names = System.IO.Directory.GetFiles(directory);
+				bool hasMatch = false;
+				for (int fileIndex = 0; fileIndex < names.Length; ++fileIndex)
+				{
+					if (!fileFilter_.IsMatch(names[fileIndex]))
+					{
+						names[fileIndex] = null;
+					}
+					else
+					{
+						hasMatch = true;
+					}
+				}
+
+				OnProcessDirectory(directory, hasMatch);
+
+				if (alive_ && hasMatch)
+				{
+					foreach (string fileName in names)
+					{
+						try
+						{
+							if (fileName != null)
+							{
+								OnProcessFile(fileName);
+								if (!alive_)
+								{
+									break;
+								}
+							}
+						}
+						catch (Exception e)
+						{
+							if (!OnFileFailure(fileName, e))
+							{
+								throw;
+							}
+						}
+					}
+				}
+			}
+			catch (Exception e)
+			{
+				if (!OnDirectoryFailure(directory, e))
+				{
+					throw;
+				}
+			}
+
+			if (alive_ && recurse)
+			{
+				try
+				{
+					string[] names = System.IO.Directory.GetDirectories(directory);
+					foreach (string fulldir in names)
+					{
+						if ((directoryFilter_ == null) || (directoryFilter_.IsMatch(fulldir)))
+						{
+							ScanDir(fulldir, true);
+							if (!alive_)
+							{
+								break;
+							}
+						}
+					}
+				}
+				catch (Exception e)
+				{
+					if (!OnDirectoryFailure(directory, e))
+					{
+						throw;
+					}
+				}
+			}
+		}
+
+		#region Instance Fields
+
+		/// <summary>
+		/// The file filter currently in use.
+		/// </summary>
+		private IScanFilter fileFilter_;
+
+		/// <summary>
+		/// The directory filter currently in use.
+		/// </summary>
+		private IScanFilter directoryFilter_;
+
+		/// <summary>
+		/// Flag indicating if scanning should continue running.
+		/// </summary>
+		private bool alive_;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Core/INameTransform.cs

@@ -0,0 +1,22 @@
+namespace ICSharpCode.SharpZipLib.Core
+{
+	/// <summary>
+	/// INameTransform defines how file system names are transformed for use with archives, or vice versa.
+	/// </summary>
+	public interface INameTransform
+	{
+		/// <summary>
+		/// Given a file name determine the transformed value.
+		/// </summary>
+		/// <param name="name">The name to transform.</param>
+		/// <returns>The transformed file name.</returns>
+		string TransformFile(string name);
+
+		/// <summary>
+		/// Given a directory name determine the transformed value.
+		/// </summary>
+		/// <param name="name">The name to transform.</param>
+		/// <returns>The transformed directory name</returns>
+		string TransformDirectory(string name);
+	}
+}

ICSharpCode.SharpZipLib/Core/IScanFilter.cs

@@ -0,0 +1,15 @@
+namespace ICSharpCode.SharpZipLib.Core
+{
+	/// <summary>
+	/// Scanning filters support filtering of names.
+	/// </summary>
+	public interface IScanFilter
+	{
+		/// <summary>
+		/// Test a name to see if it 'matches' the filter.
+		/// </summary>
+		/// <param name="name">The name to test.</param>
+		/// <returns>Returns true if the name matches the filter, false if it does not match.</returns>
+		bool IsMatch(string name);
+	}
+}

ICSharpCode.SharpZipLib/Core/InvalidNameException.cs

@@ -0,0 +1,35 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Core
+{
+	/// <summary>
+	/// InvalidNameException is thrown for invalid names such as directory traversal paths and names with invalid characters
+	/// </summary>
+	public class InvalidNameException : SharpZipBaseException
+	{
+		/// <summary>
+		/// Initializes a new instance of the InvalidNameException class with a default error message.
+		/// </summary>
+		public InvalidNameException() : base("An invalid name was specified")
+		{
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the InvalidNameException class with a specified error message.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		public InvalidNameException(string message) : base(message)
+		{
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the InvalidNameException class with a specified
+		/// error message and a reference to the inner exception that is the cause of this exception.
+		/// </summary>
+		/// <param name="message">A message describing the exception.</param>
+		/// <param name="innerException">The inner exception</param>
+		public InvalidNameException(string message, Exception innerException) : base(message, innerException)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Core/NameFilter.cs

@@ -0,0 +1,284 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Text.RegularExpressions;
+
+namespace ICSharpCode.SharpZipLib.Core
+{
+	/// <summary>
+	/// NameFilter is a string matching class which allows for both positive and negative
+	/// matching.
+	/// A filter is a sequence of independant <see cref="Regex">regular expressions</see> separated by semi-colons ';'.
+	/// To include a semi-colon it may be quoted as in \;. Each expression can be prefixed by a plus '+' sign or
+	/// a minus '-' sign to denote the expression is intended to include or exclude names.
+	/// If neither a plus or minus sign is found include is the default.
+	/// A given name is tested for inclusion before checking exclusions.  Only names matching an include spec
+	/// and not matching an exclude spec are deemed to match the filter.
+	/// An empty filter matches any name.
+	/// </summary>
+	/// <example>The following expression includes all name ending in '.dat' with the exception of 'dummy.dat'
+	/// "+\.dat$;-^dummy\.dat$"
+	/// </example>
+	public class NameFilter : IScanFilter
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Construct an instance based on the filter expression passed
+		/// </summary>
+		/// <param name="filter">The filter expression.</param>
+		public NameFilter(string filter)
+		{
+			filter_ = filter;
+			inclusions_ = new List<Regex>();
+			exclusions_ = new List<Regex>();
+			Compile();
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Test a string to see if it is a valid regular expression.
+		/// </summary>
+		/// <param name="expression">The expression to test.</param>
+		/// <returns>True if expression is a valid <see cref="System.Text.RegularExpressions.Regex"/> false otherwise.</returns>
+		public static bool IsValidExpression(string expression)
+		{
+			bool result = true;
+			try
+			{
+				var exp = new Regex(expression, RegexOptions.IgnoreCase | RegexOptions.Singleline);
+			}
+			catch (ArgumentException)
+			{
+				result = false;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Test an expression to see if it is valid as a filter.
+		/// </summary>
+		/// <param name="toTest">The filter expression to test.</param>
+		/// <returns>True if the expression is valid, false otherwise.</returns>
+		public static bool IsValidFilterExpression(string toTest)
+		{
+			bool result = true;
+
+			try
+			{
+				if (toTest != null)
+				{
+					string[] items = SplitQuoted(toTest);
+					for (int i = 0; i < items.Length; ++i)
+					{
+						if ((items[i] != null) && (items[i].Length > 0))
+						{
+							string toCompile;
+
+							if (items[i][0] == '+')
+							{
+								toCompile = items[i].Substring(1, items[i].Length - 1);
+							}
+							else if (items[i][0] == '-')
+							{
+								toCompile = items[i].Substring(1, items[i].Length - 1);
+							}
+							else
+							{
+								toCompile = items[i];
+							}
+
+							var testRegex = new Regex(toCompile, RegexOptions.IgnoreCase | RegexOptions.Singleline);
+						}
+					}
+				}
+			}
+			catch (ArgumentException)
+			{
+				result = false;
+			}
+
+			return result;
+		}
+
+		/// <summary>
+		/// Split a string into its component pieces
+		/// </summary>
+		/// <param name="original">The original string</param>
+		/// <returns>Returns an array of <see cref="T:System.String"/> values containing the individual filter elements.</returns>
+		public static string[] SplitQuoted(string original)
+		{
+			char escape = '\\';
+			char[] separators = { ';' };
+
+			var result = new List<string>();
+
+			if (!string.IsNullOrEmpty(original))
+			{
+				int endIndex = -1;
+				var b = new StringBuilder();
+
+				while (endIndex < original.Length)
+				{
+					endIndex += 1;
+					if (endIndex >= original.Length)
+					{
+						result.Add(b.ToString());
+					}
+					else if (original[endIndex] == escape)
+					{
+						endIndex += 1;
+						if (endIndex >= original.Length)
+						{
+							throw new ArgumentException("Missing terminating escape character", nameof(original));
+						}
+						// include escape if this is not an escaped separator
+						if (Array.IndexOf(separators, original[endIndex]) < 0)
+							b.Append(escape);
+
+						b.Append(original[endIndex]);
+					}
+					else
+					{
+						if (Array.IndexOf(separators, original[endIndex]) >= 0)
+						{
+							result.Add(b.ToString());
+							b.Length = 0;
+						}
+						else
+						{
+							b.Append(original[endIndex]);
+						}
+					}
+				}
+			}
+
+			return result.ToArray();
+		}
+
+		/// <summary>
+		/// Convert this filter to its string equivalent.
+		/// </summary>
+		/// <returns>The string equivalent for this filter.</returns>
+		public override string ToString()
+		{
+			return filter_;
+		}
+
+		/// <summary>
+		/// Test a value to see if it is included by the filter.
+		/// </summary>
+		/// <param name="name">The value to test.</param>
+		/// <returns>True if the value is included, false otherwise.</returns>
+		public bool IsIncluded(string name)
+		{
+			bool result = false;
+			if (inclusions_.Count == 0)
+			{
+				result = true;
+			}
+			else
+			{
+				foreach (Regex r in inclusions_)
+				{
+					if (r.IsMatch(name))
+					{
+						result = true;
+						break;
+					}
+				}
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Test a value to see if it is excluded by the filter.
+		/// </summary>
+		/// <param name="name">The value to test.</param>
+		/// <returns>True if the value is excluded, false otherwise.</returns>
+		public bool IsExcluded(string name)
+		{
+			bool result = false;
+			foreach (Regex r in exclusions_)
+			{
+				if (r.IsMatch(name))
+				{
+					result = true;
+					break;
+				}
+			}
+			return result;
+		}
+
+		#region IScanFilter Members
+
+		/// <summary>
+		/// Test a value to see if it matches the filter.
+		/// </summary>
+		/// <param name="name">The value to test.</param>
+		/// <returns>True if the value matches, false otherwise.</returns>
+		public bool IsMatch(string name)
+		{
+			return (IsIncluded(name) && !IsExcluded(name));
+		}
+
+		#endregion IScanFilter Members
+
+		/// <summary>
+		/// Compile this filter.
+		/// </summary>
+		private void Compile()
+		{
+			// TODO: Check to see if combining RE's makes it faster/smaller.
+			// simple scheme would be to have one RE for inclusion and one for exclusion.
+			if (filter_ == null)
+			{
+				return;
+			}
+
+			string[] items = SplitQuoted(filter_);
+			for (int i = 0; i < items.Length; ++i)
+			{
+				if ((items[i] != null) && (items[i].Length > 0))
+				{
+					bool include = (items[i][0] != '-');
+					string toCompile;
+
+					if (items[i][0] == '+')
+					{
+						toCompile = items[i].Substring(1, items[i].Length - 1);
+					}
+					else if (items[i][0] == '-')
+					{
+						toCompile = items[i].Substring(1, items[i].Length - 1);
+					}
+					else
+					{
+						toCompile = items[i];
+					}
+
+					// NOTE: Regular expressions can fail to compile here for a number of reasons that cause an exception
+					// these are left unhandled here as the caller is responsible for ensuring all is valid.
+					// several functions IsValidFilterExpression and IsValidExpression are provided for such checking
+					if (include)
+					{
+						inclusions_.Add(new Regex(toCompile, RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Singleline));
+					}
+					else
+					{
+						exclusions_.Add(new Regex(toCompile, RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Singleline));
+					}
+				}
+			}
+		}
+
+		#region Instance Fields
+
+		private string filter_;
+		private List<Regex> inclusions_;
+		private List<Regex> exclusions_;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Core/PathFilter.cs

@@ -0,0 +1,318 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Core
+{
+	/// <summary>
+	/// PathFilter filters directories and files using a form of <see cref="System.Text.RegularExpressions.Regex">regular expressions</see>
+	/// by full path name.
+	/// See <see cref="NameFilter">NameFilter</see> for more detail on filtering.
+	/// </summary>
+	public class PathFilter : IScanFilter
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="PathFilter"></see>.
+		/// </summary>
+		/// <param name="filter">The <see cref="NameFilter">filter</see> expression to apply.</param>
+		public PathFilter(string filter)
+		{
+			nameFilter_ = new NameFilter(filter);
+		}
+
+		#endregion Constructors
+
+		#region IScanFilter Members
+
+		/// <summary>
+		/// Test a name to see if it matches the filter.
+		/// </summary>
+		/// <param name="name">The name to test.</param>
+		/// <returns>True if the name matches, false otherwise.</returns>
+		/// <remarks><see cref="Path.GetFullPath(string)"/> is used to get the full path before matching.</remarks>
+		public virtual bool IsMatch(string name)
+		{
+			bool result = false;
+
+			if (name != null)
+			{
+				string cooked = (name.Length > 0) ? Path.GetFullPath(name) : "";
+				result = nameFilter_.IsMatch(cooked);
+			}
+			return result;
+		}
+
+		private readonly
+
+		#endregion IScanFilter Members
+
+		#region Instance Fields
+
+		NameFilter nameFilter_;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// ExtendedPathFilter filters based on name, file size, and the last write time of the file.
+	/// </summary>
+	/// <remarks>Provides an example of how to customise filtering.</remarks>
+	public class ExtendedPathFilter : PathFilter
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a new instance of ExtendedPathFilter.
+		/// </summary>
+		/// <param name="filter">The filter to apply.</param>
+		/// <param name="minSize">The minimum file size to include.</param>
+		/// <param name="maxSize">The maximum file size to include.</param>
+		public ExtendedPathFilter(string filter,
+			long minSize, long maxSize)
+			: base(filter)
+		{
+			MinSize = minSize;
+			MaxSize = maxSize;
+		}
+
+		/// <summary>
+		/// Initialise a new instance of ExtendedPathFilter.
+		/// </summary>
+		/// <param name="filter">The filter to apply.</param>
+		/// <param name="minDate">The minimum <see cref="DateTime"/> to include.</param>
+		/// <param name="maxDate">The maximum <see cref="DateTime"/> to include.</param>
+		public ExtendedPathFilter(string filter,
+			DateTime minDate, DateTime maxDate)
+			: base(filter)
+		{
+			MinDate = minDate;
+			MaxDate = maxDate;
+		}
+
+		/// <summary>
+		/// Initialise a new instance of ExtendedPathFilter.
+		/// </summary>
+		/// <param name="filter">The filter to apply.</param>
+		/// <param name="minSize">The minimum file size to include.</param>
+		/// <param name="maxSize">The maximum file size to include.</param>
+		/// <param name="minDate">The minimum <see cref="DateTime"/> to include.</param>
+		/// <param name="maxDate">The maximum <see cref="DateTime"/> to include.</param>
+		public ExtendedPathFilter(string filter,
+			long minSize, long maxSize,
+			DateTime minDate, DateTime maxDate)
+			: base(filter)
+		{
+			MinSize = minSize;
+			MaxSize = maxSize;
+			MinDate = minDate;
+			MaxDate = maxDate;
+		}
+
+		#endregion Constructors
+
+		#region IScanFilter Members
+
+		/// <summary>
+		/// Test a filename to see if it matches the filter.
+		/// </summary>
+		/// <param name="name">The filename to test.</param>
+		/// <returns>True if the filter matches, false otherwise.</returns>
+		/// <exception cref="System.IO.FileNotFoundException">The <see paramref="fileName"/> doesnt exist</exception>
+		public override bool IsMatch(string name)
+		{
+			bool result = base.IsMatch(name);
+
+			if (result)
+			{
+				var fileInfo = new FileInfo(name);
+				result =
+					(MinSize <= fileInfo.Length) &&
+					(MaxSize >= fileInfo.Length) &&
+					(MinDate <= fileInfo.LastWriteTime) &&
+					(MaxDate >= fileInfo.LastWriteTime)
+					;
+			}
+			return result;
+		}
+
+		#endregion IScanFilter Members
+
+		#region Properties
+
+		/// <summary>
+		/// Get/set the minimum size/length for a file that will match this filter.
+		/// </summary>
+		/// <remarks>The default value is zero.</remarks>
+		/// <exception cref="ArgumentOutOfRangeException">value is less than zero; greater than <see cref="MaxSize"/></exception>
+		public long MinSize
+		{
+			get { return minSize_; }
+			set
+			{
+				if ((value < 0) || (maxSize_ < value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+
+				minSize_ = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set the maximum size/length for a file that will match this filter.
+		/// </summary>
+		/// <remarks>The default value is <see cref="System.Int64.MaxValue"/></remarks>
+		/// <exception cref="ArgumentOutOfRangeException">value is less than zero or less than <see cref="MinSize"/></exception>
+		public long MaxSize
+		{
+			get { return maxSize_; }
+			set
+			{
+				if ((value < 0) || (minSize_ > value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+
+				maxSize_ = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set the minimum <see cref="DateTime"/> value that will match for this filter.
+		/// </summary>
+		/// <remarks>Files with a LastWrite time less than this value are excluded by the filter.</remarks>
+		public DateTime MinDate
+		{
+			get
+			{
+				return minDate_;
+			}
+
+			set
+			{
+				if (value > maxDate_)
+				{
+					throw new ArgumentOutOfRangeException(nameof(value), "Exceeds MaxDate");
+				}
+
+				minDate_ = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set the maximum <see cref="DateTime"/> value that will match for this filter.
+		/// </summary>
+		/// <remarks>Files with a LastWrite time greater than this value are excluded by the filter.</remarks>
+		public DateTime MaxDate
+		{
+			get
+			{
+				return maxDate_;
+			}
+
+			set
+			{
+				if (minDate_ > value)
+				{
+					throw new ArgumentOutOfRangeException(nameof(value), "Exceeds MinDate");
+				}
+
+				maxDate_ = value;
+			}
+		}
+
+		#endregion Properties
+
+		#region Instance Fields
+
+		private long minSize_;
+		private long maxSize_ = long.MaxValue;
+		private DateTime minDate_ = DateTime.MinValue;
+		private DateTime maxDate_ = DateTime.MaxValue;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// NameAndSizeFilter filters based on name and file size.
+	/// </summary>
+	/// <remarks>A sample showing how filters might be extended.</remarks>
+	[Obsolete("Use ExtendedPathFilter instead")]
+	public class NameAndSizeFilter : PathFilter
+	{
+		/// <summary>
+		/// Initialise a new instance of NameAndSizeFilter.
+		/// </summary>
+		/// <param name="filter">The filter to apply.</param>
+		/// <param name="minSize">The minimum file size to include.</param>
+		/// <param name="maxSize">The maximum file size to include.</param>
+		public NameAndSizeFilter(string filter, long minSize, long maxSize)
+			: base(filter)
+		{
+			MinSize = minSize;
+			MaxSize = maxSize;
+		}
+
+		/// <summary>
+		/// Test a filename to see if it matches the filter.
+		/// </summary>
+		/// <param name="name">The filename to test.</param>
+		/// <returns>True if the filter matches, false otherwise.</returns>
+		public override bool IsMatch(string name)
+		{
+			bool result = base.IsMatch(name);
+
+			if (result)
+			{
+				var fileInfo = new FileInfo(name);
+				long length = fileInfo.Length;
+				result =
+					(MinSize <= length) &&
+					(MaxSize >= length);
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Get/set the minimum size for a file that will match this filter.
+		/// </summary>
+		public long MinSize
+		{
+			get { return minSize_; }
+			set
+			{
+				if ((value < 0) || (maxSize_ < value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+
+				minSize_ = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set the maximum size for a file that will match this filter.
+		/// </summary>
+		public long MaxSize
+		{
+			get { return maxSize_; }
+			set
+			{
+				if ((value < 0) || (minSize_ > value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+
+				maxSize_ = value;
+			}
+		}
+
+		#region Instance Fields
+
+		private long minSize_;
+		private long maxSize_ = long.MaxValue;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Core/StreamUtils.cs

@@ -0,0 +1,284 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Core
+{
+	/// <summary>
+	/// Provides simple <see cref="Stream"/>" utilities.
+	/// </summary>
+	public sealed class StreamUtils
+	{
+		/// <summary>
+		/// Read from a <see cref="Stream"/> ensuring all the required data is read.
+		/// </summary>
+		/// <param name="stream">The stream to read.</param>
+		/// <param name="buffer">The buffer to fill.</param>
+		/// <seealso cref="ReadFully(Stream,byte[],int,int)"/>
+		static public void ReadFully(Stream stream, byte[] buffer)
+		{
+			ReadFully(stream, buffer, 0, buffer.Length);
+		}
+
+		/// <summary>
+		/// Read from a <see cref="Stream"/>" ensuring all the required data is read.
+		/// </summary>
+		/// <param name="stream">The stream to read data from.</param>
+		/// <param name="buffer">The buffer to store data in.</param>
+		/// <param name="offset">The offset at which to begin storing data.</param>
+		/// <param name="count">The number of bytes of data to store.</param>
+		/// <exception cref="ArgumentNullException">Required parameter is null</exception>
+		/// <exception cref="ArgumentOutOfRangeException"><paramref name="offset"/> and or <paramref name="count"/> are invalid.</exception>
+		/// <exception cref="EndOfStreamException">End of stream is encountered before all the data has been read.</exception>
+		static public void ReadFully(Stream stream, byte[] buffer, int offset, int count)
+		{
+			if (stream == null)
+			{
+				throw new ArgumentNullException(nameof(stream));
+			}
+
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			// Offset can equal length when buffer and count are 0.
+			if ((offset < 0) || (offset > buffer.Length))
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset));
+			}
+
+			if ((count < 0) || (offset + count > buffer.Length))
+			{
+				throw new ArgumentOutOfRangeException(nameof(count));
+			}
+
+			while (count > 0)
+			{
+				int readCount = stream.Read(buffer, offset, count);
+				if (readCount <= 0)
+				{
+					throw new EndOfStreamException();
+				}
+				offset += readCount;
+				count -= readCount;
+			}
+		}
+
+		/// <summary>
+		/// Read as much data as possible from a <see cref="Stream"/>", up to the requested number of bytes
+		/// </summary>
+		/// <param name="stream">The stream to read data from.</param>
+		/// <param name="buffer">The buffer to store data in.</param>
+		/// <param name="offset">The offset at which to begin storing data.</param>
+		/// <param name="count">The number of bytes of data to store.</param>
+		/// <exception cref="ArgumentNullException">Required parameter is null</exception>
+		/// <exception cref="ArgumentOutOfRangeException"><paramref name="offset"/> and or <paramref name="count"/> are invalid.</exception>
+		static public int ReadRequestedBytes(Stream stream, byte[] buffer, int offset, int count)
+		{
+			if (stream == null)
+			{
+				throw new ArgumentNullException(nameof(stream));
+			}
+
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			// Offset can equal length when buffer and count are 0.
+			if ((offset < 0) || (offset > buffer.Length))
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset));
+			}
+
+			if ((count < 0) || (offset + count > buffer.Length))
+			{
+				throw new ArgumentOutOfRangeException(nameof(count));
+			}
+
+			int totalReadCount = 0;
+			while (count > 0)
+			{
+				int readCount = stream.Read(buffer, offset, count);
+				if (readCount <= 0)
+				{
+					break;
+				}
+				offset += readCount;
+				count -= readCount;
+				totalReadCount += readCount;
+			}
+
+			return totalReadCount;
+		}
+
+		/// <summary>
+		/// Copy the contents of one <see cref="Stream"/> to another.
+		/// </summary>
+		/// <param name="source">The stream to source data from.</param>
+		/// <param name="destination">The stream to write data to.</param>
+		/// <param name="buffer">The buffer to use during copying.</param>
+		static public void Copy(Stream source, Stream destination, byte[] buffer)
+		{
+			if (source == null)
+			{
+				throw new ArgumentNullException(nameof(source));
+			}
+
+			if (destination == null)
+			{
+				throw new ArgumentNullException(nameof(destination));
+			}
+
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			// Ensure a reasonable size of buffer is used without being prohibitive.
+			if (buffer.Length < 128)
+			{
+				throw new ArgumentException("Buffer is too small", nameof(buffer));
+			}
+
+			bool copying = true;
+
+			while (copying)
+			{
+				int bytesRead = source.Read(buffer, 0, buffer.Length);
+				if (bytesRead > 0)
+				{
+					destination.Write(buffer, 0, bytesRead);
+				}
+				else
+				{
+					destination.Flush();
+					copying = false;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Copy the contents of one <see cref="Stream"/> to another.
+		/// </summary>
+		/// <param name="source">The stream to source data from.</param>
+		/// <param name="destination">The stream to write data to.</param>
+		/// <param name="buffer">The buffer to use during copying.</param>
+		/// <param name="progressHandler">The <see cref="ProgressHandler">progress handler delegate</see> to use.</param>
+		/// <param name="updateInterval">The minimum <see cref="TimeSpan"/> between progress updates.</param>
+		/// <param name="sender">The source for this event.</param>
+		/// <param name="name">The name to use with the event.</param>
+		/// <remarks>This form is specialised for use within #Zip to support events during archive operations.</remarks>
+		static public void Copy(Stream source, Stream destination,
+			byte[] buffer, ProgressHandler progressHandler, TimeSpan updateInterval, object sender, string name)
+		{
+			Copy(source, destination, buffer, progressHandler, updateInterval, sender, name, -1);
+		}
+
+		/// <summary>
+		/// Copy the contents of one <see cref="Stream"/> to another.
+		/// </summary>
+		/// <param name="source">The stream to source data from.</param>
+		/// <param name="destination">The stream to write data to.</param>
+		/// <param name="buffer">The buffer to use during copying.</param>
+		/// <param name="progressHandler">The <see cref="ProgressHandler">progress handler delegate</see> to use.</param>
+		/// <param name="updateInterval">The minimum <see cref="TimeSpan"/> between progress updates.</param>
+		/// <param name="sender">The source for this event.</param>
+		/// <param name="name">The name to use with the event.</param>
+		/// <param name="fixedTarget">A predetermined fixed target value to use with progress updates.
+		/// If the value is negative the target is calculated by looking at the stream.</param>
+		/// <remarks>This form is specialised for use within #Zip to support events during archive operations.</remarks>
+		static public void Copy(Stream source, Stream destination,
+			byte[] buffer,
+			ProgressHandler progressHandler, TimeSpan updateInterval,
+			object sender, string name, long fixedTarget)
+		{
+			if (source == null)
+			{
+				throw new ArgumentNullException(nameof(source));
+			}
+
+			if (destination == null)
+			{
+				throw new ArgumentNullException(nameof(destination));
+			}
+
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			// Ensure a reasonable size of buffer is used without being prohibitive.
+			if (buffer.Length < 128)
+			{
+				throw new ArgumentException("Buffer is too small", nameof(buffer));
+			}
+
+			if (progressHandler == null)
+			{
+				throw new ArgumentNullException(nameof(progressHandler));
+			}
+
+			bool copying = true;
+
+			DateTime marker = DateTime.Now;
+			long processed = 0;
+			long target = 0;
+
+			if (fixedTarget >= 0)
+			{
+				target = fixedTarget;
+			}
+			else if (source.CanSeek)
+			{
+				target = source.Length - source.Position;
+			}
+
+			// Always fire 0% progress..
+			var args = new ProgressEventArgs(name, processed, target);
+			progressHandler(sender, args);
+
+			bool progressFired = true;
+
+			while (copying)
+			{
+				int bytesRead = source.Read(buffer, 0, buffer.Length);
+				if (bytesRead > 0)
+				{
+					processed += bytesRead;
+					progressFired = false;
+					destination.Write(buffer, 0, bytesRead);
+				}
+				else
+				{
+					destination.Flush();
+					copying = false;
+				}
+
+				if (DateTime.Now - marker > updateInterval)
+				{
+					progressFired = true;
+					marker = DateTime.Now;
+					args = new ProgressEventArgs(name, processed, target);
+					progressHandler(sender, args);
+
+					copying = args.ContinueRunning;
+				}
+			}
+
+			if (!progressFired)
+			{
+				args = new ProgressEventArgs(name, processed, target);
+				progressHandler(sender, args);
+			}
+		}
+
+		/// <summary>
+		/// Initialise an instance of <see cref="StreamUtils"></see>
+		/// </summary>
+		private StreamUtils()
+		{
+			// Do nothing.
+		}
+	}
+}

ICSharpCode.SharpZipLib/Core/WindowsPathUtils.cs

@@ -0,0 +1,67 @@
+namespace ICSharpCode.SharpZipLib.Core
+{
+	/// <summary>
+	/// WindowsPathUtils provides simple utilities for handling windows paths.
+	/// </summary>
+	public abstract class WindowsPathUtils
+	{
+		/// <summary>
+		/// Initializes a new instance of the <see cref="WindowsPathUtils"/> class.
+		/// </summary>
+		internal WindowsPathUtils()
+		{
+		}
+
+		/// <summary>
+		/// Remove any path root present in the path
+		/// </summary>
+		/// <param name="path">A <see cref="string"/> containing path information.</param>
+		/// <returns>The path with the root removed if it was present; path otherwise.</returns>
+		/// <remarks>Unlike the <see cref="System.IO.Path"/> class the path isnt otherwise checked for validity.</remarks>
+		public static string DropPathRoot(string path)
+		{
+			string result = path;
+
+			if (!string.IsNullOrEmpty(path))
+			{
+				if ((path[0] == '\\') || (path[0] == '/'))
+				{
+					// UNC name ?
+					if ((path.Length > 1) && ((path[1] == '\\') || (path[1] == '/')))
+					{
+						int index = 2;
+						int elements = 2;
+
+						// Scan for two separate elements \\machine\share\restofpath
+						while ((index <= path.Length) &&
+							(((path[index] != '\\') && (path[index] != '/')) || (--elements > 0)))
+						{
+							index++;
+						}
+
+						index++;
+
+						if (index < path.Length)
+						{
+							result = path.Substring(index);
+						}
+						else
+						{
+							result = "";
+						}
+					}
+				}
+				else if ((path.Length > 1) && (path[1] == ':'))
+				{
+					int dropCount = 2;
+					if ((path.Length > 2) && ((path[2] == '\\') || (path[2] == '/')))
+					{
+						dropCount = 3;
+					}
+					result = result.Remove(0, dropCount);
+				}
+			}
+			return result;
+		}
+	}
+}

ICSharpCode.SharpZipLib/Encryption/PkzipClassic.cs

@@ -0,0 +1,485 @@
+using ICSharpCode.SharpZipLib.Checksum;
+using System;
+using System.Security.Cryptography;
+
+namespace ICSharpCode.SharpZipLib.Encryption
+{
+	/// <summary>
+	/// PkzipClassic embodies the classic or original encryption facilities used in Pkzip archives.
+	/// While it has been superceded by more recent and more powerful algorithms, its still in use and
+	/// is viable for preventing casual snooping
+	/// </summary>
+	public abstract class PkzipClassic : SymmetricAlgorithm
+	{
+		/// <summary>
+		/// Generates new encryption keys based on given seed
+		/// </summary>
+		/// <param name="seed">The seed value to initialise keys with.</param>
+		/// <returns>A new key value.</returns>
+		static public byte[] GenerateKeys(byte[] seed)
+		{
+			if (seed == null)
+			{
+				throw new ArgumentNullException(nameof(seed));
+			}
+
+			if (seed.Length == 0)
+			{
+				throw new ArgumentException("Length is zero", nameof(seed));
+			}
+
+			uint[] newKeys = {
+				0x12345678,
+				0x23456789,
+				0x34567890
+			 };
+
+			for (int i = 0; i < seed.Length; ++i)
+			{
+				newKeys[0] = Crc32.ComputeCrc32(newKeys[0], seed[i]);
+				newKeys[1] = newKeys[1] + (byte)newKeys[0];
+				newKeys[1] = newKeys[1] * 134775813 + 1;
+				newKeys[2] = Crc32.ComputeCrc32(newKeys[2], (byte)(newKeys[1] >> 24));
+			}
+
+			byte[] result = new byte[12];
+			result[0] = (byte)(newKeys[0] & 0xff);
+			result[1] = (byte)((newKeys[0] >> 8) & 0xff);
+			result[2] = (byte)((newKeys[0] >> 16) & 0xff);
+			result[3] = (byte)((newKeys[0] >> 24) & 0xff);
+			result[4] = (byte)(newKeys[1] & 0xff);
+			result[5] = (byte)((newKeys[1] >> 8) & 0xff);
+			result[6] = (byte)((newKeys[1] >> 16) & 0xff);
+			result[7] = (byte)((newKeys[1] >> 24) & 0xff);
+			result[8] = (byte)(newKeys[2] & 0xff);
+			result[9] = (byte)((newKeys[2] >> 8) & 0xff);
+			result[10] = (byte)((newKeys[2] >> 16) & 0xff);
+			result[11] = (byte)((newKeys[2] >> 24) & 0xff);
+			return result;
+		}
+	}
+
+	/// <summary>
+	/// PkzipClassicCryptoBase provides the low level facilities for encryption
+	/// and decryption using the PkzipClassic algorithm.
+	/// </summary>
+	internal class PkzipClassicCryptoBase
+	{
+		/// <summary>
+		/// Transform a single byte
+		/// </summary>
+		/// <returns>
+		/// The transformed value
+		/// </returns>
+		protected byte TransformByte()
+		{
+			uint temp = ((keys[2] & 0xFFFF) | 2);
+			return (byte)((temp * (temp ^ 1)) >> 8);
+		}
+
+		/// <summary>
+		/// Set the key schedule for encryption/decryption.
+		/// </summary>
+		/// <param name="keyData">The data use to set the keys from.</param>
+		protected void SetKeys(byte[] keyData)
+		{
+			if (keyData == null)
+			{
+				throw new ArgumentNullException(nameof(keyData));
+			}
+
+			if (keyData.Length != 12)
+			{
+				throw new InvalidOperationException("Key length is not valid");
+			}
+
+			keys = new uint[3];
+			keys[0] = (uint)((keyData[3] << 24) | (keyData[2] << 16) | (keyData[1] << 8) | keyData[0]);
+			keys[1] = (uint)((keyData[7] << 24) | (keyData[6] << 16) | (keyData[5] << 8) | keyData[4]);
+			keys[2] = (uint)((keyData[11] << 24) | (keyData[10] << 16) | (keyData[9] << 8) | keyData[8]);
+		}
+
+		/// <summary>
+		/// Update encryption keys
+		/// </summary>
+		protected void UpdateKeys(byte ch)
+		{
+			keys[0] = Crc32.ComputeCrc32(keys[0], ch);
+			keys[1] = keys[1] + (byte)keys[0];
+			keys[1] = keys[1] * 134775813 + 1;
+			keys[2] = Crc32.ComputeCrc32(keys[2], (byte)(keys[1] >> 24));
+		}
+
+		/// <summary>
+		/// Reset the internal state.
+		/// </summary>
+		protected void Reset()
+		{
+			keys[0] = 0;
+			keys[1] = 0;
+			keys[2] = 0;
+		}
+
+		#region Instance Fields
+
+		private uint[] keys;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// PkzipClassic CryptoTransform for encryption.
+	/// </summary>
+	internal class PkzipClassicEncryptCryptoTransform : PkzipClassicCryptoBase, ICryptoTransform
+	{
+		/// <summary>
+		/// Initialise a new instance of <see cref="PkzipClassicEncryptCryptoTransform"></see>
+		/// </summary>
+		/// <param name="keyBlock">The key block to use.</param>
+		internal PkzipClassicEncryptCryptoTransform(byte[] keyBlock)
+		{
+			SetKeys(keyBlock);
+		}
+
+		#region ICryptoTransform Members
+
+		/// <summary>
+		/// Transforms the specified region of the specified byte array.
+		/// </summary>
+		/// <param name="inputBuffer">The input for which to compute the transform.</param>
+		/// <param name="inputOffset">The offset into the byte array from which to begin using data.</param>
+		/// <param name="inputCount">The number of bytes in the byte array to use as data.</param>
+		/// <returns>The computed transform.</returns>
+		public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
+		{
+			byte[] result = new byte[inputCount];
+			TransformBlock(inputBuffer, inputOffset, inputCount, result, 0);
+			return result;
+		}
+
+		/// <summary>
+		/// Transforms the specified region of the input byte array and copies
+		/// the resulting transform to the specified region of the output byte array.
+		/// </summary>
+		/// <param name="inputBuffer">The input for which to compute the transform.</param>
+		/// <param name="inputOffset">The offset into the input byte array from which to begin using data.</param>
+		/// <param name="inputCount">The number of bytes in the input byte array to use as data.</param>
+		/// <param name="outputBuffer">The output to which to write the transform.</param>
+		/// <param name="outputOffset">The offset into the output byte array from which to begin writing data.</param>
+		/// <returns>The number of bytes written.</returns>
+		public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
+		{
+			for (int i = inputOffset; i < inputOffset + inputCount; ++i)
+			{
+				byte oldbyte = inputBuffer[i];
+				outputBuffer[outputOffset++] = (byte)(inputBuffer[i] ^ TransformByte());
+				UpdateKeys(oldbyte);
+			}
+			return inputCount;
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether the current transform can be reused.
+		/// </summary>
+		public bool CanReuseTransform
+		{
+			get
+			{
+				return true;
+			}
+		}
+
+		/// <summary>
+		/// Gets the size of the input data blocks in bytes.
+		/// </summary>
+		public int InputBlockSize
+		{
+			get
+			{
+				return 1;
+			}
+		}
+
+		/// <summary>
+		/// Gets the size of the output data blocks in bytes.
+		/// </summary>
+		public int OutputBlockSize
+		{
+			get
+			{
+				return 1;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether multiple blocks can be transformed.
+		/// </summary>
+		public bool CanTransformMultipleBlocks
+		{
+			get
+			{
+				return true;
+			}
+		}
+
+		#endregion ICryptoTransform Members
+
+		#region IDisposable Members
+
+		/// <summary>
+		/// Cleanup internal state.
+		/// </summary>
+		public void Dispose()
+		{
+			Reset();
+		}
+
+		#endregion IDisposable Members
+	}
+
+	/// <summary>
+	/// PkzipClassic CryptoTransform for decryption.
+	/// </summary>
+	internal class PkzipClassicDecryptCryptoTransform : PkzipClassicCryptoBase, ICryptoTransform
+	{
+		/// <summary>
+		/// Initialise a new instance of <see cref="PkzipClassicDecryptCryptoTransform"></see>.
+		/// </summary>
+		/// <param name="keyBlock">The key block to decrypt with.</param>
+		internal PkzipClassicDecryptCryptoTransform(byte[] keyBlock)
+		{
+			SetKeys(keyBlock);
+		}
+
+		#region ICryptoTransform Members
+
+		/// <summary>
+		/// Transforms the specified region of the specified byte array.
+		/// </summary>
+		/// <param name="inputBuffer">The input for which to compute the transform.</param>
+		/// <param name="inputOffset">The offset into the byte array from which to begin using data.</param>
+		/// <param name="inputCount">The number of bytes in the byte array to use as data.</param>
+		/// <returns>The computed transform.</returns>
+		public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
+		{
+			byte[] result = new byte[inputCount];
+			TransformBlock(inputBuffer, inputOffset, inputCount, result, 0);
+			return result;
+		}
+
+		/// <summary>
+		/// Transforms the specified region of the input byte array and copies
+		/// the resulting transform to the specified region of the output byte array.
+		/// </summary>
+		/// <param name="inputBuffer">The input for which to compute the transform.</param>
+		/// <param name="inputOffset">The offset into the input byte array from which to begin using data.</param>
+		/// <param name="inputCount">The number of bytes in the input byte array to use as data.</param>
+		/// <param name="outputBuffer">The output to which to write the transform.</param>
+		/// <param name="outputOffset">The offset into the output byte array from which to begin writing data.</param>
+		/// <returns>The number of bytes written.</returns>
+		public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
+		{
+			for (int i = inputOffset; i < inputOffset + inputCount; ++i)
+			{
+				var newByte = (byte)(inputBuffer[i] ^ TransformByte());
+				outputBuffer[outputOffset++] = newByte;
+				UpdateKeys(newByte);
+			}
+			return inputCount;
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether the current transform can be reused.
+		/// </summary>
+		public bool CanReuseTransform
+		{
+			get
+			{
+				return true;
+			}
+		}
+
+		/// <summary>
+		/// Gets the size of the input data blocks in bytes.
+		/// </summary>
+		public int InputBlockSize
+		{
+			get
+			{
+				return 1;
+			}
+		}
+
+		/// <summary>
+		/// Gets the size of the output data blocks in bytes.
+		/// </summary>
+		public int OutputBlockSize
+		{
+			get
+			{
+				return 1;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether multiple blocks can be transformed.
+		/// </summary>
+		public bool CanTransformMultipleBlocks
+		{
+			get
+			{
+				return true;
+			}
+		}
+
+		#endregion ICryptoTransform Members
+
+		#region IDisposable Members
+
+		/// <summary>
+		/// Cleanup internal state.
+		/// </summary>
+		public void Dispose()
+		{
+			Reset();
+		}
+
+		#endregion IDisposable Members
+	}
+
+	/// <summary>
+	/// Defines a wrapper object to access the Pkzip algorithm.
+	/// This class cannot be inherited.
+	/// </summary>
+	public sealed class PkzipClassicManaged : PkzipClassic
+	{
+		/// <summary>
+		/// Get / set the applicable block size in bits.
+		/// </summary>
+		/// <remarks>The only valid block size is 8.</remarks>
+		public override int BlockSize
+		{
+			get
+			{
+				return 8;
+			}
+
+			set
+			{
+				if (value != 8)
+				{
+					throw new CryptographicException("Block size is invalid");
+				}
+			}
+		}
+
+		/// <summary>
+		/// Get an array of legal <see cref="KeySizes">key sizes.</see>
+		/// </summary>
+		public override KeySizes[] LegalKeySizes
+		{
+			get
+			{
+				KeySizes[] keySizes = new KeySizes[1];
+				keySizes[0] = new KeySizes(12 * 8, 12 * 8, 0);
+				return keySizes;
+			}
+		}
+
+		/// <summary>
+		/// Generate an initial vector.
+		/// </summary>
+		public override void GenerateIV()
+		{
+			// Do nothing.
+		}
+
+		/// <summary>
+		/// Get an array of legal <see cref="KeySizes">block sizes</see>.
+		/// </summary>
+		public override KeySizes[] LegalBlockSizes
+		{
+			get
+			{
+				KeySizes[] keySizes = new KeySizes[1];
+				keySizes[0] = new KeySizes(1 * 8, 1 * 8, 0);
+				return keySizes;
+			}
+		}
+
+		/// <summary>
+		/// Get / set the key value applicable.
+		/// </summary>
+		public override byte[] Key
+		{
+			get
+			{
+				if (key_ == null)
+				{
+					GenerateKey();
+				}
+
+				return (byte[])key_.Clone();
+			}
+
+			set
+			{
+				if (value == null)
+				{
+					throw new ArgumentNullException(nameof(value));
+				}
+
+				if (value.Length != 12)
+				{
+					throw new CryptographicException("Key size is illegal");
+				}
+
+				key_ = (byte[])value.Clone();
+			}
+		}
+
+		/// <summary>
+		/// Generate a new random key.
+		/// </summary>
+		public override void GenerateKey()
+		{
+			key_ = new byte[12];
+			var rnd = new Random();
+			rnd.NextBytes(key_);
+		}
+
+		/// <summary>
+		/// Create an encryptor.
+		/// </summary>
+		/// <param name="rgbKey">The key to use for this encryptor.</param>
+		/// <param name="rgbIV">Initialisation vector for the new encryptor.</param>
+		/// <returns>Returns a new PkzipClassic encryptor</returns>
+		public override ICryptoTransform CreateEncryptor(
+			byte[] rgbKey,
+			byte[] rgbIV)
+		{
+			key_ = rgbKey;
+			return new PkzipClassicEncryptCryptoTransform(Key);
+		}
+
+		/// <summary>
+		/// Create a decryptor.
+		/// </summary>
+		/// <param name="rgbKey">Keys to use for this new decryptor.</param>
+		/// <param name="rgbIV">Initialisation vector for the new decryptor.</param>
+		/// <returns>Returns a new decryptor.</returns>
+		public override ICryptoTransform CreateDecryptor(
+			byte[] rgbKey,
+			byte[] rgbIV)
+		{
+			key_ = rgbKey;
+			return new PkzipClassicDecryptCryptoTransform(Key);
+		}
+
+		#region Instance Fields
+
+		private byte[] key_;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Encryption/ZipAESStream.cs

@@ -0,0 +1,146 @@
+using System;
+using System.IO;
+using System.Security.Cryptography;
+using ICSharpCode.SharpZipLib.Core;
+
+namespace ICSharpCode.SharpZipLib.Encryption
+{
+	/// <summary>
+	/// Encrypts and decrypts AES ZIP
+	/// </summary>
+	/// <remarks>
+	/// Based on information from http://www.winzip.com/aes_info.htm
+	/// and http://www.gladman.me.uk/cryptography_technology/fileencrypt/
+	/// </remarks>
+	internal class ZipAESStream : CryptoStream
+	{
+		/// <summary>
+		/// Constructor
+		/// </summary>
+		/// <param name="stream">The stream on which to perform the cryptographic transformation.</param>
+		/// <param name="transform">Instance of ZipAESTransform</param>
+		/// <param name="mode">Read or Write</param>
+		public ZipAESStream(Stream stream, ZipAESTransform transform, CryptoStreamMode mode)
+			: base(stream, transform, mode)
+		{
+			_stream = stream;
+			_transform = transform;
+			_slideBuffer = new byte[1024];
+
+			_blockAndAuth = CRYPTO_BLOCK_SIZE + AUTH_CODE_LENGTH;
+
+			// mode:
+			//  CryptoStreamMode.Read means we read from "stream" and pass decrypted to our Read() method.
+			//  Write bypasses this stream and uses the Transform directly.
+			if (mode != CryptoStreamMode.Read)
+			{
+				throw new Exception("ZipAESStream only for read");
+			}
+		}
+
+		// The final n bytes of the AES stream contain the Auth Code.
+		private const int AUTH_CODE_LENGTH = 10;
+
+		private Stream _stream;
+		private ZipAESTransform _transform;
+		private byte[] _slideBuffer;
+		private int _slideBufStartPos;
+		private int _slideBufFreePos;
+
+		// Blocksize is always 16 here, even for AES-256 which has transform.InputBlockSize of 32.
+		private const int CRYPTO_BLOCK_SIZE = 16;
+
+		private int _blockAndAuth;
+
+		/// <summary>
+		/// Reads a sequence of bytes from the current CryptoStream into buffer,
+		/// and advances the position within the stream by the number of bytes read.
+		/// </summary>
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			int nBytes = 0;
+			while (nBytes < count)
+			{
+				// Calculate buffer quantities vs read-ahead size, and check for sufficient free space
+				int byteCount = _slideBufFreePos - _slideBufStartPos;
+
+				// Need to handle final block and Auth Code specially, but don't know total data length.
+				// Maintain a read-ahead equal to the length of (crypto block + Auth Code).
+				// When that runs out we can detect these final sections.
+				int lengthToRead = _blockAndAuth - byteCount;
+				if (_slideBuffer.Length - _slideBufFreePos < lengthToRead)
+				{
+					// Shift the data to the beginning of the buffer
+					int iTo = 0;
+					for (int iFrom = _slideBufStartPos; iFrom < _slideBufFreePos; iFrom++, iTo++)
+					{
+						_slideBuffer[iTo] = _slideBuffer[iFrom];
+					}
+					_slideBufFreePos -= _slideBufStartPos;      // Note the -=
+					_slideBufStartPos = 0;
+				}
+				int obtained = StreamUtils.ReadRequestedBytes(_stream, _slideBuffer, _slideBufFreePos, lengthToRead);
+				_slideBufFreePos += obtained;
+
+				// Recalculate how much data we now have
+				byteCount = _slideBufFreePos - _slideBufStartPos;
+				if (byteCount >= _blockAndAuth)
+				{
+					// At least a 16 byte block and an auth code remains.
+					_transform.TransformBlock(_slideBuffer,
+											  _slideBufStartPos,
+											  CRYPTO_BLOCK_SIZE,
+											  buffer,
+											  offset);
+					nBytes += CRYPTO_BLOCK_SIZE;
+					offset += CRYPTO_BLOCK_SIZE;
+					_slideBufStartPos += CRYPTO_BLOCK_SIZE;
+				}
+				else
+				{
+					// Last round.
+					if (byteCount > AUTH_CODE_LENGTH)
+					{
+						// At least one byte of data plus auth code
+						int finalBlock = byteCount - AUTH_CODE_LENGTH;
+						_transform.TransformBlock(_slideBuffer,
+												  _slideBufStartPos,
+												  finalBlock,
+												  buffer,
+												  offset);
+
+						nBytes += finalBlock;
+						_slideBufStartPos += finalBlock;
+					}
+					else if (byteCount < AUTH_CODE_LENGTH)
+						throw new Exception("Internal error missed auth code"); // Coding bug
+																				// Final block done. Check Auth code.
+					byte[] calcAuthCode = _transform.GetAuthCode();
+					for (int i = 0; i < AUTH_CODE_LENGTH; i++)
+					{
+						if (calcAuthCode[i] != _slideBuffer[_slideBufStartPos + i])
+						{
+							throw new Exception("AES Authentication Code does not match. This is a super-CRC check on the data in the file after compression and encryption. \r\n"
+								+ "The file may be damaged.");
+						}
+					}
+
+					break;  // Reached the auth code
+				}
+			}
+			return nBytes;
+		}
+
+		/// <summary>
+		/// Writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.
+		/// </summary>
+		/// <param name="buffer">An array of bytes. This method copies count bytes from buffer to the current stream. </param>
+		/// <param name="offset">The byte offset in buffer at which to begin copying bytes to the current stream. </param>
+		/// <param name="count">The number of bytes to be written to the current stream. </param>
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			// ZipAESStream is used for reading but not for writing. Writing uses the ZipAESTransform directly.
+			throw new NotImplementedException();
+		}
+	}
+}

ICSharpCode.SharpZipLib/Encryption/ZipAESTransform.cs

@@ -0,0 +1,223 @@
+using System;
+using System.Security.Cryptography;
+
+namespace ICSharpCode.SharpZipLib.Encryption
+{
+	/// <summary>
+	/// Transforms stream using AES in CTR mode
+	/// </summary>
+	internal class ZipAESTransform : ICryptoTransform
+	{
+#if NET45
+		class IncrementalHash : HMACSHA1
+		{
+			bool _finalised;
+			public IncrementalHash(byte[] key) : base(key) { }
+			public static IncrementalHash CreateHMAC(string n, byte[] key) => new IncrementalHash(key);
+			public void AppendData(byte[] buffer, int offset, int count) => TransformBlock(buffer, offset, count, buffer, offset);
+			public byte[] GetHashAndReset()
+			{
+				if (!_finalised)
+				{
+					byte[] dummy = new byte[0];
+					TransformFinalBlock(dummy, 0, 0);
+					_finalised = true;
+				}
+				return Hash;
+			}
+		}
+
+		static class HashAlgorithmName
+		{
+			public static string SHA1 = null;
+		}
+#endif
+
+		private const int PWD_VER_LENGTH = 2;
+
+		// WinZip use iteration count of 1000 for PBKDF2 key generation
+		private const int KEY_ROUNDS = 1000;
+
+		// For 128-bit AES (16 bytes) the encryption is implemented as expected.
+		// For 256-bit AES (32 bytes) WinZip do full 256 bit AES of the nonce to create the encryption
+		// block but use only the first 16 bytes of it, and discard the second half.
+		private const int ENCRYPT_BLOCK = 16;
+
+		private int _blockSize;
+		private readonly ICryptoTransform _encryptor;
+		private readonly byte[] _counterNonce;
+		private byte[] _encryptBuffer;
+		private int _encrPos;
+		private byte[] _pwdVerifier;
+		private IncrementalHash _hmacsha1;
+		private byte[] _authCode = null;
+
+		private bool _writeMode;
+
+		/// <summary>
+		/// Constructor.
+		/// </summary>
+		/// <param name="key">Password string</param>
+		/// <param name="saltBytes">Random bytes, length depends on encryption strength.
+		/// 128 bits = 8 bytes, 192 bits = 12 bytes, 256 bits = 16 bytes.</param>
+		/// <param name="blockSize">The encryption strength, in bytes eg 16 for 128 bits.</param>
+		/// <param name="writeMode">True when creating a zip, false when reading. For the AuthCode.</param>
+		///
+		public ZipAESTransform(string key, byte[] saltBytes, int blockSize, bool writeMode)
+		{
+			if (blockSize != 16 && blockSize != 32) // 24 valid for AES but not supported by Winzip
+				throw new Exception("Invalid blocksize " + blockSize + ". Must be 16 or 32.");
+			if (saltBytes.Length != blockSize / 2)
+				throw new Exception("Invalid salt len. Must be " + blockSize / 2 + " for blocksize " + blockSize);
+			// initialise the encryption buffer and buffer pos
+			_blockSize = blockSize;
+			_encryptBuffer = new byte[_blockSize];
+			_encrPos = ENCRYPT_BLOCK;
+
+			// Performs the equivalent of derive_key in Dr Brian Gladman's pwd2key.c
+			var pdb = new Rfc2898DeriveBytes(key, saltBytes, KEY_ROUNDS);
+			var rm = Aes.Create();
+			rm.Mode = CipherMode.ECB;           // No feedback from cipher for CTR mode
+			_counterNonce = new byte[_blockSize];
+			byte[] key1bytes = pdb.GetBytes(_blockSize);
+			byte[] key2bytes = pdb.GetBytes(_blockSize);
+
+			// Use empty IV for AES
+			_encryptor = rm.CreateEncryptor(key1bytes, new byte[16]);
+			_pwdVerifier = pdb.GetBytes(PWD_VER_LENGTH);
+			//
+			_hmacsha1 = IncrementalHash.CreateHMAC(HashAlgorithmName.SHA1, key2bytes);
+			_writeMode = writeMode;
+		}
+
+		/// <summary>
+		/// Implement the ICryptoTransform method.
+		/// </summary>
+		public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
+		{
+			// Pass the data stream to the hash algorithm for generating the Auth Code.
+			// This does not change the inputBuffer. Do this before decryption for read mode.
+			if (!_writeMode)
+			{
+				_hmacsha1.AppendData(inputBuffer, inputOffset, inputCount);
+			}
+			// Encrypt with AES in CTR mode. Regards to Dr Brian Gladman for this.
+			int ix = 0;
+			while (ix < inputCount)
+			{
+				if (_encrPos == ENCRYPT_BLOCK)
+				{
+					/* increment encryption nonce   */
+					int j = 0;
+					while (++_counterNonce[j] == 0)
+					{
+						++j;
+					}
+					/* encrypt the nonce to form next xor buffer    */
+					_encryptor.TransformBlock(_counterNonce, 0, _blockSize, _encryptBuffer, 0);
+					_encrPos = 0;
+				}
+				outputBuffer[ix + outputOffset] = (byte)(inputBuffer[ix + inputOffset] ^ _encryptBuffer[_encrPos++]);
+				//
+				ix++;
+			}
+			if (_writeMode)
+			{
+				// This does not change the buffer.
+				_hmacsha1.AppendData(outputBuffer, outputOffset, inputCount);
+			}
+			return inputCount;
+		}
+
+		/// <summary>
+		/// Returns the 2 byte password verifier
+		/// </summary>
+		public byte[] PwdVerifier
+		{
+			get
+			{
+				return _pwdVerifier;
+			}
+		}
+
+		/// <summary>
+		/// Returns the 10 byte AUTH CODE to be checked or appended immediately following the AES data stream.
+		/// </summary>
+		public byte[] GetAuthCode()
+		{
+			if (_authCode == null)
+			{
+				_authCode = _hmacsha1.GetHashAndReset();
+			}
+			return _authCode;
+		}
+
+		#region ICryptoTransform Members
+
+		/// <summary>
+		/// Not implemented.
+		/// </summary>
+		public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
+		{
+			if(inputCount > 0)
+			{
+				throw new NotImplementedException("TransformFinalBlock is not implemented and inputCount is greater than 0");
+			}
+			return new byte[0];
+		}
+
+		/// <summary>
+		/// Gets the size of the input data blocks in bytes.
+		/// </summary>
+		public int InputBlockSize
+		{
+			get
+			{
+				return _blockSize;
+			}
+		}
+
+		/// <summary>
+		/// Gets the size of the output data blocks in bytes.
+		/// </summary>
+		public int OutputBlockSize
+		{
+			get
+			{
+				return _blockSize;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether multiple blocks can be transformed.
+		/// </summary>
+		public bool CanTransformMultipleBlocks
+		{
+			get
+			{
+				return true;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether the current transform can be reused.
+		/// </summary>
+		public bool CanReuseTransform
+		{
+			get
+			{
+				return true;
+			}
+		}
+
+		/// <summary>
+		/// Cleanup internal state.
+		/// </summary>
+		public void Dispose()
+		{
+			_encryptor.Dispose();
+		}
+
+		#endregion ICryptoTransform Members
+	}
+}

ICSharpCode.SharpZipLib/GZip/GZip.cs

@@ -0,0 +1,92 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.GZip
+{
+	using static Zip.Compression.Deflater;
+
+	/// <summary>
+	/// An example class to demonstrate compression and decompression of GZip streams.
+	/// </summary>
+	public static class GZip
+	{
+		/// <summary>
+		/// Decompress the <paramref name="inStream">input</paramref> writing
+		/// uncompressed data to the <paramref name="outStream">output stream</paramref>
+		/// </summary>
+		/// <param name="inStream">The readable stream containing data to decompress.</param>
+		/// <param name="outStream">The output stream to receive the decompressed data.</param>
+		/// <param name="isStreamOwner">Both streams are closed on completion if true.</param>
+		/// <exception cref="ArgumentNullException">Input or output stream is null</exception>
+		public static void Decompress(Stream inStream, Stream outStream, bool isStreamOwner)
+		{
+			if (inStream == null)
+				throw new ArgumentNullException(nameof(inStream), "Input stream is null");
+
+			if (outStream == null)
+				throw new ArgumentNullException(nameof(outStream), "Output stream is null");
+
+			try
+			{
+				using (GZipInputStream gzipInput = new GZipInputStream(inStream))
+				{
+					gzipInput.IsStreamOwner = isStreamOwner;
+					Core.StreamUtils.Copy(gzipInput, outStream, new byte[4096]);
+				}
+			}
+			finally
+			{
+				if (isStreamOwner)
+				{
+					// inStream is closed by the GZipInputStream if stream owner
+					outStream.Dispose();
+				}
+			}
+		}
+
+		/// <summary>
+		/// Compress the <paramref name="inStream">input stream</paramref> sending
+		/// result data to <paramref name="outStream">output stream</paramref>
+		/// </summary>
+		/// <param name="inStream">The readable stream to compress.</param>
+		/// <param name="outStream">The output stream to receive the compressed data.</param>
+		/// <param name="isStreamOwner">Both streams are closed on completion if true.</param>
+		/// <param name="bufferSize">Deflate buffer size, minimum 512</param>
+		/// <param name="level">Deflate compression level, 0-9</param>
+		/// <exception cref="ArgumentNullException">Input or output stream is null</exception>
+		/// <exception cref="ArgumentOutOfRangeException">Buffer Size is smaller than 512</exception>
+		/// <exception cref="ArgumentOutOfRangeException">Compression level outside 0-9</exception>
+		public static void Compress(Stream inStream, Stream outStream, bool isStreamOwner, int bufferSize = 512, int level = 6)
+		{
+			if (inStream == null)
+				throw new ArgumentNullException(nameof(inStream), "Input stream is null");
+
+			if (outStream == null)
+				throw new ArgumentNullException(nameof(outStream), "Output stream is null");
+
+			if (bufferSize < 512)
+				throw new ArgumentOutOfRangeException(nameof(bufferSize), "Deflate buffer size must be >= 512");
+
+			if (level < NO_COMPRESSION || level > BEST_COMPRESSION)
+				throw new ArgumentOutOfRangeException(nameof(level), "Compression level must be 0-9");
+
+			try
+			{
+				using (GZipOutputStream gzipOutput = new GZipOutputStream(outStream, bufferSize))
+				{
+					gzipOutput.SetLevel(level);
+					gzipOutput.IsStreamOwner = isStreamOwner;
+					Core.StreamUtils.Copy(inStream, gzipOutput, new byte[bufferSize]);
+				}
+			}
+			finally
+			{
+				if (isStreamOwner)
+				{
+					// outStream is closed by the GZipOutputStream if stream owner
+					inStream.Dispose();
+				}
+			}
+		}
+	}
+}

ICSharpCode.SharpZipLib/GZip/GZipConstants.cs

@@ -0,0 +1,58 @@
+namespace ICSharpCode.SharpZipLib.GZip
+{
+	/// <summary>
+	/// This class contains constants used for gzip.
+	/// </summary>
+	sealed public class GZipConstants
+	{
+		/// <summary>
+		/// Magic number found at start of GZIP header
+		/// </summary>
+		public const int GZIP_MAGIC = 0x1F8B;
+
+		/*  The flag byte is divided into individual bits as follows:
+
+			bit 0   FTEXT
+			bit 1   FHCRC
+			bit 2   FEXTRA
+			bit 3   FNAME
+			bit 4   FCOMMENT
+			bit 5   reserved
+			bit 6   reserved
+			bit 7   reserved
+		 */
+
+		/// <summary>
+		/// Flag bit mask for text
+		/// </summary>
+		public const int FTEXT = 0x1;
+
+		/// <summary>
+		/// Flag bitmask for Crc
+		/// </summary>
+		public const int FHCRC = 0x2;
+
+		/// <summary>
+		/// Flag bit mask for extra
+		/// </summary>
+		public const int FEXTRA = 0x4;
+
+		/// <summary>
+		/// flag bitmask for name
+		/// </summary>
+		public const int FNAME = 0x8;
+
+		/// <summary>
+		/// flag bit mask indicating comment is present
+		/// </summary>
+		public const int FCOMMENT = 0x10;
+
+		/// <summary>
+		/// Initialise default instance.
+		/// </summary>
+		/// <remarks>Constructor is private to prevent instances being created.</remarks>
+		private GZipConstants()
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/GZip/GZipException.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.GZip
+{
+	/// <summary>
+	/// GZipException represents exceptions specific to GZip classes and code.
+	/// </summary>
+	public class GZipException : SharpZipBaseException
+	{
+		/// <summary>
+		/// Initialise a new instance of <see cref="GZipException" />.
+		/// </summary>
+		public GZipException()
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="GZipException" /> with its message string.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		public GZipException(string message)
+			: base(message)
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="GZipException" />.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		/// <param name="innerException">The <see cref="Exception"/> that caused this exception.</param>
+		public GZipException(string message, Exception innerException)
+			: base(message, innerException)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/GZip/GzipInputStream.cs

@@ -0,0 +1,389 @@
+using ICSharpCode.SharpZipLib.Checksum;
+using ICSharpCode.SharpZipLib.Zip.Compression;
+using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.GZip
+{
+	/// <summary>
+	/// This filter stream is used to decompress a "GZIP" format stream.
+	/// The "GZIP" format is described baseInputStream RFC 1952.
+	///
+	/// author of the original java version : John Leuner
+	/// </summary>
+	/// <example> This sample shows how to unzip a gzipped file
+	/// <code>
+	/// using System;
+	/// using System.IO;
+	///
+	/// using ICSharpCode.SharpZipLib.Core;
+	/// using ICSharpCode.SharpZipLib.GZip;
+	///
+	/// class MainClass
+	/// {
+	/// 	public static void Main(string[] args)
+	/// 	{
+	///			using (Stream inStream = new GZipInputStream(File.OpenRead(args[0])))
+	///			using (FileStream outStream = File.Create(Path.GetFileNameWithoutExtension(args[0]))) {
+	///				byte[] buffer = new byte[4096];
+	///				StreamUtils.Copy(inStream, outStream, buffer);
+	/// 		}
+	/// 	}
+	/// }
+	/// </code>
+	/// </example>
+	public class GZipInputStream : InflaterInputStream
+	{
+		#region Instance Fields
+
+		/// <summary>
+		/// CRC-32 value for uncompressed data
+		/// </summary>
+		protected Crc32 crc;
+
+		/// <summary>
+		/// Flag to indicate if we've read the GZIP header yet for the current member (block of compressed data).
+		/// This is tracked per-block as the file is parsed.
+		/// </summary>
+		private bool readGZIPHeader;
+
+		/// <summary>
+		/// Flag to indicate if at least one block in a stream with concatenated blocks was read successfully.
+		/// This allows us to exit gracefully if downstream data is not in gzip format.
+		/// </summary>
+		private bool completedLastBlock;
+
+		#endregion Instance Fields
+
+		#region Constructors
+
+		/// <summary>
+		/// Creates a GZipInputStream with the default buffer size
+		/// </summary>
+		/// <param name="baseInputStream">
+		/// The stream to read compressed data from (baseInputStream GZIP format)
+		/// </param>
+		public GZipInputStream(Stream baseInputStream)
+			: this(baseInputStream, 4096)
+		{
+		}
+
+		/// <summary>
+		/// Creates a GZIPInputStream with the specified buffer size
+		/// </summary>
+		/// <param name="baseInputStream">
+		/// The stream to read compressed data from (baseInputStream GZIP format)
+		/// </param>
+		/// <param name="size">
+		/// Size of the buffer to use
+		/// </param>
+		public GZipInputStream(Stream baseInputStream, int size)
+			: base(baseInputStream, new Inflater(true), size)
+		{
+		}
+
+		#endregion Constructors
+
+		#region Stream overrides
+
+		/// <summary>
+		/// Reads uncompressed data into an array of bytes
+		/// </summary>
+		/// <param name="buffer">
+		/// The buffer to read uncompressed data into
+		/// </param>
+		/// <param name="offset">
+		/// The offset indicating where the data should be placed
+		/// </param>
+		/// <param name="count">
+		/// The number of uncompressed bytes to be read
+		/// </param>
+		/// <returns>Returns the number of bytes actually read.</returns>
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			// A GZIP file can contain multiple blocks of compressed data, although this is quite rare.
+			// A compressed block could potentially be empty, so we need to loop until we reach EOF or
+			// we find data.
+			while (true)
+			{
+				// If we haven't read the header for this block, read it
+				if (!readGZIPHeader)
+				{
+					// Try to read header. If there is no header (0 bytes available), this is EOF. If there is
+					// an incomplete header, this will throw an exception.
+					try
+					{
+						if (!ReadHeader())
+						{
+							return 0;
+						}
+					}
+					catch (Exception ex) when (completedLastBlock && (ex is GZipException || ex is EndOfStreamException))
+					{
+						// if we completed the last block (i.e. we're in a stream that has multiple blocks concatenated
+						// we want to return gracefully from any header parsing exceptions since sometimes there may
+						// be trailing garbage on a stream
+						return 0;
+					}
+				}
+
+				// Try to read compressed data
+				int bytesRead = base.Read(buffer, offset, count);
+				if (bytesRead > 0)
+				{
+					crc.Update(new ArraySegment<byte>(buffer, offset, bytesRead));
+				}
+
+				// If this is the end of stream, read the footer
+				if (inf.IsFinished)
+				{
+					ReadFooter();
+				}
+
+				if (bytesRead > 0)
+				{
+					return bytesRead;
+				}
+			}
+		}
+
+		#endregion Stream overrides
+
+		#region Support routines
+
+		private bool ReadHeader()
+		{
+			// Initialize CRC for this block
+			crc = new Crc32();
+
+			// Make sure there is data in file. We can't rely on ReadLeByte() to fill the buffer, as this could be EOF,
+			// which is fine, but ReadLeByte() throws an exception if it doesn't find data, so we do this part ourselves.
+			if (inputBuffer.Available <= 0)
+			{
+				inputBuffer.Fill();
+				if (inputBuffer.Available <= 0)
+				{
+					// No header, EOF.
+					return false;
+				}
+			}
+
+			// 1. Check the two magic bytes
+			var headCRC = new Crc32();
+			int magic = inputBuffer.ReadLeByte();
+
+			if (magic < 0)
+			{
+				throw new EndOfStreamException("EOS reading GZIP header");
+			}
+
+			headCRC.Update(magic);
+			if (magic != (GZipConstants.GZIP_MAGIC >> 8))
+			{
+				throw new GZipException("Error GZIP header, first magic byte doesn't match");
+			}
+
+			//magic = baseInputStream.ReadByte();
+			magic = inputBuffer.ReadLeByte();
+
+			if (magic < 0)
+			{
+				throw new EndOfStreamException("EOS reading GZIP header");
+			}
+
+			if (magic != (GZipConstants.GZIP_MAGIC & 0xFF))
+			{
+				throw new GZipException("Error GZIP header,  second magic byte doesn't match");
+			}
+
+			headCRC.Update(magic);
+
+			// 2. Check the compression type (must be 8)
+			int compressionType = inputBuffer.ReadLeByte();
+
+			if (compressionType < 0)
+			{
+				throw new EndOfStreamException("EOS reading GZIP header");
+			}
+
+			if (compressionType != 8)
+			{
+				throw new GZipException("Error GZIP header, data not in deflate format");
+			}
+			headCRC.Update(compressionType);
+
+			// 3. Check the flags
+			int flags = inputBuffer.ReadLeByte();
+			if (flags < 0)
+			{
+				throw new EndOfStreamException("EOS reading GZIP header");
+			}
+			headCRC.Update(flags);
+
+			/*    This flag byte is divided into individual bits as follows:
+
+			bit 0   FTEXT
+			bit 1   FHCRC
+			bit 2   FEXTRA
+			bit 3   FNAME
+			bit 4   FCOMMENT
+			bit 5   reserved
+			bit 6   reserved
+			bit 7   reserved
+			*/
+
+			// 3.1 Check the reserved bits are zero
+
+			if ((flags & 0xE0) != 0)
+			{
+				throw new GZipException("Reserved flag bits in GZIP header != 0");
+			}
+
+			// 4.-6. Skip the modification time, extra flags, and OS type
+			for (int i = 0; i < 6; i++)
+			{
+				int readByte = inputBuffer.ReadLeByte();
+				if (readByte < 0)
+				{
+					throw new EndOfStreamException("EOS reading GZIP header");
+				}
+				headCRC.Update(readByte);
+			}
+
+			// 7. Read extra field
+			if ((flags & GZipConstants.FEXTRA) != 0)
+			{
+				// XLEN is total length of extra subfields, we will skip them all
+				int len1, len2;
+				len1 = inputBuffer.ReadLeByte();
+				len2 = inputBuffer.ReadLeByte();
+				if ((len1 < 0) || (len2 < 0))
+				{
+					throw new EndOfStreamException("EOS reading GZIP header");
+				}
+				headCRC.Update(len1);
+				headCRC.Update(len2);
+
+				int extraLen = (len2 << 8) | len1;      // gzip is LSB first
+				for (int i = 0; i < extraLen; i++)
+				{
+					int readByte = inputBuffer.ReadLeByte();
+					if (readByte < 0)
+					{
+						throw new EndOfStreamException("EOS reading GZIP header");
+					}
+					headCRC.Update(readByte);
+				}
+			}
+
+			// 8. Read file name
+			if ((flags & GZipConstants.FNAME) != 0)
+			{
+				int readByte;
+				while ((readByte = inputBuffer.ReadLeByte()) > 0)
+				{
+					headCRC.Update(readByte);
+				}
+
+				if (readByte < 0)
+				{
+					throw new EndOfStreamException("EOS reading GZIP header");
+				}
+				headCRC.Update(readByte);
+			}
+
+			// 9. Read comment
+			if ((flags & GZipConstants.FCOMMENT) != 0)
+			{
+				int readByte;
+				while ((readByte = inputBuffer.ReadLeByte()) > 0)
+				{
+					headCRC.Update(readByte);
+				}
+
+				if (readByte < 0)
+				{
+					throw new EndOfStreamException("EOS reading GZIP header");
+				}
+
+				headCRC.Update(readByte);
+			}
+
+			// 10. Read header CRC
+			if ((flags & GZipConstants.FHCRC) != 0)
+			{
+				int tempByte;
+				int crcval = inputBuffer.ReadLeByte();
+				if (crcval < 0)
+				{
+					throw new EndOfStreamException("EOS reading GZIP header");
+				}
+
+				tempByte = inputBuffer.ReadLeByte();
+				if (tempByte < 0)
+				{
+					throw new EndOfStreamException("EOS reading GZIP header");
+				}
+
+				crcval = (crcval << 8) | tempByte;
+				if (crcval != ((int)headCRC.Value & 0xffff))
+				{
+					throw new GZipException("Header CRC value mismatch");
+				}
+			}
+
+			readGZIPHeader = true;
+			return true;
+		}
+
+		private void ReadFooter()
+		{
+			byte[] footer = new byte[8];
+
+			// End of stream; reclaim all bytes from inf, read the final byte count, and reset the inflator
+			long bytesRead = inf.TotalOut & 0xffffffff;
+			inputBuffer.Available += inf.RemainingInput;
+			inf.Reset();
+
+			// Read footer from inputBuffer
+			int needed = 8;
+			while (needed > 0)
+			{
+				int count = inputBuffer.ReadClearTextBuffer(footer, 8 - needed, needed);
+				if (count <= 0)
+				{
+					throw new EndOfStreamException("EOS reading GZIP footer");
+				}
+				needed -= count; // Jewel Jan 16
+			}
+
+			// Calculate CRC
+			int crcval = (footer[0] & 0xff) | ((footer[1] & 0xff) << 8) | ((footer[2] & 0xff) << 16) | (footer[3] << 24);
+			if (crcval != (int)crc.Value)
+			{
+				throw new GZipException("GZIP crc sum mismatch, theirs \"" + crcval + "\" and ours \"" + (int)crc.Value);
+			}
+
+			// NOTE The total here is the original total modulo 2 ^ 32.
+			uint total =
+				(uint)((uint)footer[4] & 0xff) |
+				(uint)(((uint)footer[5] & 0xff) << 8) |
+				(uint)(((uint)footer[6] & 0xff) << 16) |
+				(uint)((uint)footer[7] << 24);
+
+			if (bytesRead != total)
+			{
+				throw new GZipException("Number of bytes mismatch in footer");
+			}
+
+			// Mark header read as false so if another header exists, we'll continue reading through the file
+			readGZIPHeader = false;
+
+			// Indicate that we succeeded on at least one block so we can exit gracefully if there is trailing garbage downstream
+			completedLastBlock = true;
+		}
+
+		#endregion Support routines
+	}
+}

ICSharpCode.SharpZipLib/GZip/GzipOutputStream.cs

@@ -0,0 +1,240 @@
+using ICSharpCode.SharpZipLib.Checksum;
+using ICSharpCode.SharpZipLib.Zip.Compression;
+using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.GZip
+{
+	/// <summary>
+	/// This filter stream is used to compress a stream into a "GZIP" stream.
+	/// The "GZIP" format is described in RFC 1952.
+	///
+	/// author of the original java version : John Leuner
+	/// </summary>
+	/// <example> This sample shows how to gzip a file
+	/// <code>
+	/// using System;
+	/// using System.IO;
+	///
+	/// using ICSharpCode.SharpZipLib.GZip;
+	/// using ICSharpCode.SharpZipLib.Core;
+	///
+	/// class MainClass
+	/// {
+	/// 	public static void Main(string[] args)
+	/// 	{
+	/// 			using (Stream s = new GZipOutputStream(File.Create(args[0] + ".gz")))
+	/// 			using (FileStream fs = File.OpenRead(args[0])) {
+	/// 				byte[] writeData = new byte[4096];
+	/// 				Streamutils.Copy(s, fs, writeData);
+	/// 			}
+	/// 		}
+	/// 	}
+	/// }
+	/// </code>
+	/// </example>
+	public class GZipOutputStream : DeflaterOutputStream
+	{
+		private enum OutputState
+		{
+			Header,
+			Footer,
+			Finished,
+			Closed,
+		};
+
+		#region Instance Fields
+
+		/// <summary>
+		/// CRC-32 value for uncompressed data
+		/// </summary>
+		protected Crc32 crc = new Crc32();
+
+		private OutputState state_ = OutputState.Header;
+
+		#endregion Instance Fields
+
+		#region Constructors
+
+		/// <summary>
+		/// Creates a GzipOutputStream with the default buffer size
+		/// </summary>
+		/// <param name="baseOutputStream">
+		/// The stream to read data (to be compressed) from
+		/// </param>
+		public GZipOutputStream(Stream baseOutputStream)
+			: this(baseOutputStream, 4096)
+		{
+		}
+
+		/// <summary>
+		/// Creates a GZipOutputStream with the specified buffer size
+		/// </summary>
+		/// <param name="baseOutputStream">
+		/// The stream to read data (to be compressed) from
+		/// </param>
+		/// <param name="size">
+		/// Size of the buffer to use
+		/// </param>
+		public GZipOutputStream(Stream baseOutputStream, int size) : base(baseOutputStream, new Deflater(Deflater.DEFAULT_COMPRESSION, true), size)
+		{
+		}
+
+		#endregion Constructors
+
+		#region Public API
+
+		/// <summary>
+		/// Sets the active compression level (0-9).  The new level will be activated
+		/// immediately.
+		/// </summary>
+		/// <param name="level">The compression level to set.</param>
+		/// <exception cref="ArgumentOutOfRangeException">
+		/// Level specified is not supported.
+		/// </exception>
+		/// <see cref="Deflater"/>
+		public void SetLevel(int level)
+		{
+			if (level < Deflater.NO_COMPRESSION || level > Deflater.BEST_COMPRESSION)
+				throw new ArgumentOutOfRangeException(nameof(level), "Compression level must be 0-9");
+
+			deflater_.SetLevel(level);
+		}
+
+		/// <summary>
+		/// Get the current compression level.
+		/// </summary>
+		/// <returns>The current compression level.</returns>
+		public int GetLevel()
+		{
+			return deflater_.GetLevel();
+		}
+
+		#endregion Public API
+
+		#region Stream overrides
+
+		/// <summary>
+		/// Write given buffer to output updating crc
+		/// </summary>
+		/// <param name="buffer">Buffer to write</param>
+		/// <param name="offset">Offset of first byte in buf to write</param>
+		/// <param name="count">Number of bytes to write</param>
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			if (state_ == OutputState.Header)
+			{
+				WriteHeader();
+			}
+
+			if (state_ != OutputState.Footer)
+			{
+				throw new InvalidOperationException("Write not permitted in current state");
+			}
+
+			crc.Update(new ArraySegment<byte>(buffer, offset, count));
+			base.Write(buffer, offset, count);
+		}
+
+		/// <summary>
+		/// Writes remaining compressed output data to the output stream
+		/// and closes it.
+		/// </summary>
+		protected override void Dispose(bool disposing)
+		{
+			try
+			{
+				Finish();
+			}
+			finally
+			{
+				if (state_ != OutputState.Closed)
+				{
+					state_ = OutputState.Closed;
+					if (IsStreamOwner)
+					{
+						baseOutputStream_.Dispose();
+					}
+				}
+			}
+		}
+
+		#endregion Stream overrides
+
+		#region DeflaterOutputStream overrides
+
+		/// <summary>
+		/// Finish compression and write any footer information required to stream
+		/// </summary>
+		public override void Finish()
+		{
+			// If no data has been written a header should be added.
+			if (state_ == OutputState.Header)
+			{
+				WriteHeader();
+			}
+
+			if (state_ == OutputState.Footer)
+			{
+				state_ = OutputState.Finished;
+				base.Finish();
+
+				var totalin = (uint)(deflater_.TotalIn & 0xffffffff);
+				var crcval = (uint)(crc.Value & 0xffffffff);
+
+				byte[] gzipFooter;
+
+				unchecked
+				{
+					gzipFooter = new byte[] {
+					(byte) crcval, (byte) (crcval >> 8),
+					(byte) (crcval >> 16), (byte) (crcval >> 24),
+
+					(byte) totalin, (byte) (totalin >> 8),
+					(byte) (totalin >> 16), (byte) (totalin >> 24)
+				};
+				}
+
+				baseOutputStream_.Write(gzipFooter, 0, gzipFooter.Length);
+			}
+		}
+
+		#endregion DeflaterOutputStream overrides
+
+		#region Support Routines
+
+		private void WriteHeader()
+		{
+			if (state_ == OutputState.Header)
+			{
+				state_ = OutputState.Footer;
+
+				var mod_time = (int)((DateTime.Now.Ticks - new DateTime(1970, 1, 1).Ticks) / 10000000L);  // Ticks give back 100ns intervals
+				byte[] gzipHeader = {
+					// The two magic bytes
+					(byte) (GZipConstants.GZIP_MAGIC >> 8), (byte) (GZipConstants.GZIP_MAGIC & 0xff),
+
+					// The compression type
+					(byte) Deflater.DEFLATED,
+
+					// The flags (not set)
+					0,
+
+					// The modification time
+					(byte) mod_time, (byte) (mod_time >> 8),
+					(byte) (mod_time >> 16), (byte) (mod_time >> 24),
+
+					// The extra flags
+					0,
+
+					// The OS type (unknown)
+					(byte) 255
+				};
+				baseOutputStream_.Write(gzipHeader, 0, gzipHeader.Length);
+			}
+		}
+
+		#endregion Support Routines
+	}
+}

ICSharpCode.SharpZipLib/ICSharpCode.SharpZipLib.csproj

@@ -0,0 +1,52 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>netstandard2;net45</TargetFrameworks>
+    <SignAssembly>True</SignAssembly>
+    <AssemblyOriginatorKeyFile>ICSharpCode.SharpZipLib.snk</AssemblyOriginatorKeyFile>
+    <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
+		<AllowedOutputExtensionsInPackageBuildOutputFolder>$(AllowedOutputExtensionsInPackageBuildOutputFolder);.pdb</AllowedOutputExtensionsInPackageBuildOutputFolder>
+  </PropertyGroup>
+  
+  <!-- Nuget specific tags -->
+  <PropertyGroup>
+    <AssemblyVersion>1.1.0.6</AssemblyVersion>
+    <FileVersion>1.1.0.6</FileVersion>
+    <Version>1.1.0</Version>
+    <PackageId>SharpZipLib</PackageId>
+    <Company>ICSharpCode</Company>
+    <Authors>ICSharpCode</Authors>
+    <Description>SharpZipLib (#ziplib, formerly NZipLib) is a compression library for Zip, GZip, BZip2, and Tar written entirely in C# for .NET. It is implemented as an assembly (installable in the GAC), and thus can easily be incorporated into other projects (in any .NET language)</Description>
+		<PackageLicenseExpression>MIT</PackageLicenseExpression>
+		<PackageProjectUrl>http://icsharpcode.github.io/SharpZipLib/</PackageProjectUrl>
+		<PackageIconUrl>http://icsharpcode.github.io/SharpZipLib/assets/sharpziplib-nuget-256x256.png</PackageIconUrl>
+    <RepositoryUrl>https://github.com/icsharpcode/SharpZipLib</RepositoryUrl>
+    <Copyright>Copyright © 2000-2018 SharpZipLib Contributors</Copyright>
+    <PackageTags>Compression Library Zip GZip BZip2 LZW Tar</PackageTags>
+    <NeutralLanguage>en-US</NeutralLanguage>
+    <PackageReleaseNotes>
+Please see https://github.com/icsharpcode/SharpZipLib/wiki/Release-1.1 for more information.</PackageReleaseNotes>
+    <PackageProjectUrl>https://github.com/icsharpcode/SharpZipLib</PackageProjectUrl> 
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netstandard2|AnyCPU'">
+    <DocumentationFile>bin\Debug\netstandard2\ICSharpCode.SharpZipLib.xml</DocumentationFile>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|netstandard2|AnyCPU'">
+    <DocumentationFile>bin\Release\netstandard2\ICSharpCode.SharpZipLib.xml</DocumentationFile>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|net45|AnyCPU'">
+    <DocumentationFile>bin\Debug\net45\ICSharpCode.SharpZipLib.xml</DocumentationFile>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|net45|AnyCPU'">
+    <DocumentationFile>bin\Release\net45\ICSharpCode.SharpZipLib.xml</DocumentationFile>
+  </PropertyGroup>
+
+	<ItemGroup>
+		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta-63127-02" PrivateAssets="All"/>
+	</ItemGroup>
+
+</Project>

ICSharpCode.SharpZipLib/Lzw/LzwConstants.cs

@@ -0,0 +1,62 @@
+namespace ICSharpCode.SharpZipLib.Lzw
+{
+	/// <summary>
+	/// This class contains constants used for LZW
+	/// </summary>
+	sealed public class LzwConstants
+	{
+		/// <summary>
+		/// Magic number found at start of LZW header: 0x1f 0x9d
+		/// </summary>
+		public const int MAGIC = 0x1f9d;
+
+		/// <summary>
+		/// Maximum number of bits per code
+		/// </summary>
+		public const int MAX_BITS = 16;
+
+		/* 3rd header byte:
+         * bit 0..4 Number of compression bits
+         * bit 5    Extended header
+         * bit 6    Free
+         * bit 7    Block mode
+         */
+
+		/// <summary>
+		/// Mask for 'number of compression bits'
+		/// </summary>
+		public const int BIT_MASK = 0x1f;
+
+		/// <summary>
+		/// Indicates the presence of a fourth header byte
+		/// </summary>
+		public const int EXTENDED_MASK = 0x20;
+
+		//public const int FREE_MASK      = 0x40;
+
+		/// <summary>
+		/// Reserved bits
+		/// </summary>
+		public const int RESERVED_MASK = 0x60;
+
+		/// <summary>
+		/// Block compression: if table is full and compression rate is dropping,
+		/// clear the dictionary.
+		/// </summary>
+		public const int BLOCK_MODE_MASK = 0x80;
+
+		/// <summary>
+		/// LZW file header size (in bytes)
+		/// </summary>
+		public const int HDR_SIZE = 3;
+
+		/// <summary>
+		/// Initial number of bits per code
+		/// </summary>
+		public const int INIT_BITS = 9;
+
+		private LzwConstants()
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Lzw/LzwException.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Lzw
+{
+	/// <summary>
+	/// LzwException represents exceptions specific to LZW classes and code.
+	/// </summary>
+	public class LzwException : SharpZipBaseException
+	{
+		/// <summary>
+		/// Initialise a new instance of <see cref="LzwException" />.
+		/// </summary>
+		public LzwException()
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="LzwException" /> with its message string.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		public LzwException(string message)
+			: base(message)
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="LzwException" />.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		/// <param name="innerException">The <see cref="Exception"/> that caused this exception.</param>
+		public LzwException(string message, Exception innerException)
+			: base(message, innerException)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Lzw/LzwInputStream.cs

@@ -0,0 +1,572 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Lzw
+{
+	/// <summary>
+	/// This filter stream is used to decompress a LZW format stream.
+	/// Specifically, a stream that uses the LZC compression method.
+	/// This file format is usually associated with the .Z file extension.
+	///
+	/// See http://en.wikipedia.org/wiki/Compress
+	/// See http://wiki.wxwidgets.org/Development:_Z_File_Format
+	///
+	/// The file header consists of 3 (or optionally 4) bytes. The first two bytes
+	/// contain the magic marker "0x1f 0x9d", followed by a byte of flags.
+	///
+	/// Based on Java code by Ronald Tschalar, which in turn was based on the unlzw.c
+	/// code in the gzip package.
+	/// </summary>
+	/// <example> This sample shows how to unzip a compressed file
+	/// <code>
+	/// using System;
+	/// using System.IO;
+	///
+	/// using ICSharpCode.SharpZipLib.Core;
+	/// using ICSharpCode.SharpZipLib.LZW;
+	///
+	/// class MainClass
+	/// {
+	/// 	public static void Main(string[] args)
+	/// 	{
+	///			using (Stream inStream = new LzwInputStream(File.OpenRead(args[0])))
+	///			using (FileStream outStream = File.Create(Path.GetFileNameWithoutExtension(args[0]))) {
+	///				byte[] buffer = new byte[4096];
+	///				StreamUtils.Copy(inStream, outStream, buffer);
+	///                         // OR
+	///                         inStream.Read(buffer, 0, buffer.Length);
+	///                         // now do something with the buffer
+	/// 		}
+	/// 	}
+	/// }
+	/// </code>
+	/// </example>
+	public class LzwInputStream : Stream
+	{
+		/// <summary>
+		/// Gets or sets a flag indicating ownership of underlying stream.
+		/// When the flag is true <see cref="Stream.Dispose()" /> will close the underlying stream also.
+		/// </summary>
+		/// <remarks>The default value is true.</remarks>
+		public bool IsStreamOwner { get; set; } = true;
+
+		/// <summary>
+		/// Creates a LzwInputStream
+		/// </summary>
+		/// <param name="baseInputStream">
+		/// The stream to read compressed data from (baseInputStream LZW format)
+		/// </param>
+		public LzwInputStream(Stream baseInputStream)
+		{
+			this.baseInputStream = baseInputStream;
+		}
+
+		/// <summary>
+		/// See <see cref="System.IO.Stream.ReadByte"/>
+		/// </summary>
+		/// <returns></returns>
+		public override int ReadByte()
+		{
+			int b = Read(one, 0, 1);
+			if (b == 1)
+				return (one[0] & 0xff);
+			return -1;
+		}
+
+		/// <summary>
+		/// Reads decompressed data into the provided buffer byte array
+		/// </summary>
+		/// <param name ="buffer">
+		/// The array to read and decompress data into
+		/// </param>
+		/// <param name ="offset">
+		/// The offset indicating where the data should be placed
+		/// </param>
+		/// <param name ="count">
+		/// The number of bytes to decompress
+		/// </param>
+		/// <returns>The number of bytes read. Zero signals the end of stream</returns>
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			if (!headerParsed)
+				ParseHeader();
+
+			if (eof)
+				return 0;
+
+			int start = offset;
+
+			/* Using local copies of various variables speeds things up by as
+	         * much as 30% in Java! Performance not tested in C#.
+	         */
+			int[] lTabPrefix = tabPrefix;
+			byte[] lTabSuffix = tabSuffix;
+			byte[] lStack = stack;
+			int lNBits = nBits;
+			int lMaxCode = maxCode;
+			int lMaxMaxCode = maxMaxCode;
+			int lBitMask = bitMask;
+			int lOldCode = oldCode;
+			byte lFinChar = finChar;
+			int lStackP = stackP;
+			int lFreeEnt = freeEnt;
+			byte[] lData = data;
+			int lBitPos = bitPos;
+
+			// empty stack if stuff still left
+			int sSize = lStack.Length - lStackP;
+			if (sSize > 0)
+			{
+				int num = (sSize >= count) ? count : sSize;
+				Array.Copy(lStack, lStackP, buffer, offset, num);
+				offset += num;
+				count -= num;
+				lStackP += num;
+			}
+
+			if (count == 0)
+			{
+				stackP = lStackP;
+				return offset - start;
+			}
+
+		// loop, filling local buffer until enough data has been decompressed
+		MainLoop:
+			do
+			{
+				if (end < EXTRA)
+				{
+					Fill();
+				}
+
+				int bitIn = (got > 0) ? (end - end % lNBits) << 3 :
+										(end << 3) - (lNBits - 1);
+
+				while (lBitPos < bitIn)
+				{
+					#region A
+
+					// handle 1-byte reads correctly
+					if (count == 0)
+					{
+						nBits = lNBits;
+						maxCode = lMaxCode;
+						maxMaxCode = lMaxMaxCode;
+						bitMask = lBitMask;
+						oldCode = lOldCode;
+						finChar = lFinChar;
+						stackP = lStackP;
+						freeEnt = lFreeEnt;
+						bitPos = lBitPos;
+
+						return offset - start;
+					}
+
+					// check for code-width expansion
+					if (lFreeEnt > lMaxCode)
+					{
+						int nBytes = lNBits << 3;
+						lBitPos = (lBitPos - 1) +
+						nBytes - (lBitPos - 1 + nBytes) % nBytes;
+
+						lNBits++;
+						lMaxCode = (lNBits == maxBits) ? lMaxMaxCode :
+														(1 << lNBits) - 1;
+
+						lBitMask = (1 << lNBits) - 1;
+						lBitPos = ResetBuf(lBitPos);
+						goto MainLoop;
+					}
+
+					#endregion A
+
+					#region B
+
+					// read next code
+					int pos = lBitPos >> 3;
+					int code = (((lData[pos] & 0xFF) |
+						((lData[pos + 1] & 0xFF) << 8) |
+						((lData[pos + 2] & 0xFF) << 16)) >>
+						(lBitPos & 0x7)) & lBitMask;
+
+					lBitPos += lNBits;
+
+					// handle first iteration
+					if (lOldCode == -1)
+					{
+						if (code >= 256)
+							throw new LzwException("corrupt input: " + code + " > 255");
+
+						lFinChar = (byte)(lOldCode = code);
+						buffer[offset++] = lFinChar;
+						count--;
+						continue;
+					}
+
+					// handle CLEAR code
+					if (code == TBL_CLEAR && blockMode)
+					{
+						Array.Copy(zeros, 0, lTabPrefix, 0, zeros.Length);
+						lFreeEnt = TBL_FIRST - 1;
+
+						int nBytes = lNBits << 3;
+						lBitPos = (lBitPos - 1) + nBytes - (lBitPos - 1 + nBytes) % nBytes;
+						lNBits = LzwConstants.INIT_BITS;
+						lMaxCode = (1 << lNBits) - 1;
+						lBitMask = lMaxCode;
+
+						// Code tables reset
+
+						lBitPos = ResetBuf(lBitPos);
+						goto MainLoop;
+					}
+
+					#endregion B
+
+					#region C
+
+					// setup
+					int inCode = code;
+					lStackP = lStack.Length;
+
+					// Handle KwK case
+					if (code >= lFreeEnt)
+					{
+						if (code > lFreeEnt)
+						{
+							throw new LzwException("corrupt input: code=" + code +
+								", freeEnt=" + lFreeEnt);
+						}
+
+						lStack[--lStackP] = lFinChar;
+						code = lOldCode;
+					}
+
+					// Generate output characters in reverse order
+					while (code >= 256)
+					{
+						lStack[--lStackP] = lTabSuffix[code];
+						code = lTabPrefix[code];
+					}
+
+					lFinChar = lTabSuffix[code];
+					buffer[offset++] = lFinChar;
+					count--;
+
+					// And put them out in forward order
+					sSize = lStack.Length - lStackP;
+					int num = (sSize >= count) ? count : sSize;
+					Array.Copy(lStack, lStackP, buffer, offset, num);
+					offset += num;
+					count -= num;
+					lStackP += num;
+
+					#endregion C
+
+					#region D
+
+					// generate new entry in table
+					if (lFreeEnt < lMaxMaxCode)
+					{
+						lTabPrefix[lFreeEnt] = lOldCode;
+						lTabSuffix[lFreeEnt] = lFinChar;
+						lFreeEnt++;
+					}
+
+					// Remember previous code
+					lOldCode = inCode;
+
+					// if output buffer full, then return
+					if (count == 0)
+					{
+						nBits = lNBits;
+						maxCode = lMaxCode;
+						bitMask = lBitMask;
+						oldCode = lOldCode;
+						finChar = lFinChar;
+						stackP = lStackP;
+						freeEnt = lFreeEnt;
+						bitPos = lBitPos;
+
+						return offset - start;
+					}
+
+					#endregion D
+				}   // while
+
+				lBitPos = ResetBuf(lBitPos);
+			} while (got > 0);  // do..while
+
+			nBits = lNBits;
+			maxCode = lMaxCode;
+			bitMask = lBitMask;
+			oldCode = lOldCode;
+			finChar = lFinChar;
+			stackP = lStackP;
+			freeEnt = lFreeEnt;
+			bitPos = lBitPos;
+
+			eof = true;
+			return offset - start;
+		}
+
+		/// <summary>
+		/// Moves the unread data in the buffer to the beginning and resets
+		/// the pointers.
+		/// </summary>
+		/// <param name="bitPosition"></param>
+		/// <returns></returns>
+		private int ResetBuf(int bitPosition)
+		{
+			int pos = bitPosition >> 3;
+			Array.Copy(data, pos, data, 0, end - pos);
+			end -= pos;
+			return 0;
+		}
+
+		private void Fill()
+		{
+			got = baseInputStream.Read(data, end, data.Length - 1 - end);
+			if (got > 0)
+			{
+				end += got;
+			}
+		}
+
+		private void ParseHeader()
+		{
+			headerParsed = true;
+
+			byte[] hdr = new byte[LzwConstants.HDR_SIZE];
+
+			int result = baseInputStream.Read(hdr, 0, hdr.Length);
+
+			// Check the magic marker
+			if (result < 0)
+				throw new LzwException("Failed to read LZW header");
+
+			if (hdr[0] != (LzwConstants.MAGIC >> 8) || hdr[1] != (LzwConstants.MAGIC & 0xff))
+			{
+				throw new LzwException(String.Format(
+					"Wrong LZW header. Magic bytes don't match. 0x{0:x2} 0x{1:x2}",
+					hdr[0], hdr[1]));
+			}
+
+			// Check the 3rd header byte
+			blockMode = (hdr[2] & LzwConstants.BLOCK_MODE_MASK) > 0;
+			maxBits = hdr[2] & LzwConstants.BIT_MASK;
+
+			if (maxBits > LzwConstants.MAX_BITS)
+			{
+				throw new LzwException("Stream compressed with " + maxBits +
+					" bits, but decompression can only handle " +
+					LzwConstants.MAX_BITS + " bits.");
+			}
+
+			if ((hdr[2] & LzwConstants.RESERVED_MASK) > 0)
+			{
+				throw new LzwException("Unsupported bits set in the header.");
+			}
+
+			// Initialize variables
+			maxMaxCode = 1 << maxBits;
+			nBits = LzwConstants.INIT_BITS;
+			maxCode = (1 << nBits) - 1;
+			bitMask = maxCode;
+			oldCode = -1;
+			finChar = 0;
+			freeEnt = blockMode ? TBL_FIRST : 256;
+
+			tabPrefix = new int[1 << maxBits];
+			tabSuffix = new byte[1 << maxBits];
+			stack = new byte[1 << maxBits];
+			stackP = stack.Length;
+
+			for (int idx = 255; idx >= 0; idx--)
+				tabSuffix[idx] = (byte)idx;
+		}
+
+		#region Stream Overrides
+
+		/// <summary>
+		/// Gets a value indicating whether the current stream supports reading
+		/// </summary>
+		public override bool CanRead
+		{
+			get
+			{
+				return baseInputStream.CanRead;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value of false indicating seeking is not supported for this stream.
+		/// </summary>
+		public override bool CanSeek
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value of false indicating that this stream is not writeable.
+		/// </summary>
+		public override bool CanWrite
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// A value representing the length of the stream in bytes.
+		/// </summary>
+		public override long Length
+		{
+			get
+			{
+				return got;
+			}
+		}
+
+		/// <summary>
+		/// The current position within the stream.
+		/// Throws a NotSupportedException when attempting to set the position
+		/// </summary>
+		/// <exception cref="NotSupportedException">Attempting to set the position</exception>
+		public override long Position
+		{
+			get
+			{
+				return baseInputStream.Position;
+			}
+			set
+			{
+				throw new NotSupportedException("InflaterInputStream Position not supported");
+			}
+		}
+
+		/// <summary>
+		/// Flushes the baseInputStream
+		/// </summary>
+		public override void Flush()
+		{
+			baseInputStream.Flush();
+		}
+
+		/// <summary>
+		/// Sets the position within the current stream
+		/// Always throws a NotSupportedException
+		/// </summary>
+		/// <param name="offset">The relative offset to seek to.</param>
+		/// <param name="origin">The <see cref="SeekOrigin"/> defining where to seek from.</param>
+		/// <returns>The new position in the stream.</returns>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override long Seek(long offset, SeekOrigin origin)
+		{
+			throw new NotSupportedException("Seek not supported");
+		}
+
+		/// <summary>
+		/// Set the length of the current stream
+		/// Always throws a NotSupportedException
+		/// </summary>
+		/// <param name="value">The new length value for the stream.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void SetLength(long value)
+		{
+			throw new NotSupportedException("InflaterInputStream SetLength not supported");
+		}
+
+		/// <summary>
+		/// Writes a sequence of bytes to stream and advances the current position
+		/// This method always throws a NotSupportedException
+		/// </summary>
+		/// <param name="buffer">Thew buffer containing data to write.</param>
+		/// <param name="offset">The offset of the first byte to write.</param>
+		/// <param name="count">The number of bytes to write.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			throw new NotSupportedException("InflaterInputStream Write not supported");
+		}
+
+		/// <summary>
+		/// Writes one byte to the current stream and advances the current position
+		/// Always throws a NotSupportedException
+		/// </summary>
+		/// <param name="value">The byte to write.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void WriteByte(byte value)
+		{
+			throw new NotSupportedException("InflaterInputStream WriteByte not supported");
+		}
+
+		/// <summary>
+		/// Closes the input stream.  When <see cref="IsStreamOwner"></see>
+		/// is true the underlying stream is also closed.
+		/// </summary>
+		protected override void Dispose(bool disposing)
+		{
+			if (!isClosed)
+			{
+				isClosed = true;
+				if (IsStreamOwner)
+				{
+					baseInputStream.Dispose();
+				}
+			}
+		}
+
+		#endregion Stream Overrides
+
+		#region Instance Fields
+
+		private Stream baseInputStream;
+
+		/// <summary>
+		/// Flag indicating wether this instance has been closed or not.
+		/// </summary>
+		private bool isClosed;
+
+		private readonly byte[] one = new byte[1];
+		private bool headerParsed;
+
+		// string table stuff
+		private const int TBL_CLEAR = 0x100;
+
+		private const int TBL_FIRST = TBL_CLEAR + 1;
+
+		private int[] tabPrefix;
+		private byte[] tabSuffix;
+		private readonly int[] zeros = new int[256];
+		private byte[] stack;
+
+		// various state
+		private bool blockMode;
+
+		private int nBits;
+		private int maxBits;
+		private int maxMaxCode;
+		private int maxCode;
+		private int bitMask;
+		private int oldCode;
+		private byte finChar;
+		private int stackP;
+		private int freeEnt;
+
+		// input buffer
+		private readonly byte[] data = new byte[1024 * 8];
+
+		private int bitPos;
+		private int end;
+		private int got;
+		private bool eof;
+		private const int EXTRA = 64;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Tar/InvalidHeaderException.cs

@@ -0,0 +1,37 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Tar
+{
+	/// <summary>
+	/// This exception is used to indicate that there is a problem
+	/// with a TAR archive header.
+	/// </summary>
+	public class InvalidHeaderException : TarException
+	{
+		/// <summary>
+		/// Initialise a new instance of the InvalidHeaderException class.
+		/// </summary>
+		public InvalidHeaderException()
+		{
+		}
+
+		/// <summary>
+		/// Initialises a new instance of the InvalidHeaderException class with a specified message.
+		/// </summary>
+		/// <param name="message">Message describing the exception cause.</param>
+		public InvalidHeaderException(string message)
+			: base(message)
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of InvalidHeaderException
+		/// </summary>
+		/// <param name="message">Message describing the problem.</param>
+		/// <param name="exception">The exception that is the cause of the current exception.</param>
+		public InvalidHeaderException(string message, Exception exception)
+			: base(message, exception)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Tar/TarArchive.cs

@@ -0,0 +1,958 @@
+using System;
+using System.IO;
+using System.Text;
+
+namespace ICSharpCode.SharpZipLib.Tar
+{
+	/// <summary>
+	/// Used to advise clients of 'events' while processing archives
+	/// </summary>
+	public delegate void ProgressMessageHandler(TarArchive archive, TarEntry entry, string message);
+
+	/// <summary>
+	/// The TarArchive class implements the concept of a
+	/// 'Tape Archive'. A tar archive is a series of entries, each of
+	/// which represents a file system object. Each entry in
+	/// the archive consists of a header block followed by 0 or more data blocks.
+	/// Directory entries consist only of the header block, and are followed by entries
+	/// for the directory's contents. File entries consist of a
+	/// header followed by the number of blocks needed to
+	/// contain the file's contents. All entries are written on
+	/// block boundaries. Blocks are 512 bytes long.
+	///
+	/// TarArchives are instantiated in either read or write mode,
+	/// based upon whether they are instantiated with an InputStream
+	/// or an OutputStream. Once instantiated TarArchives read/write
+	/// mode can not be changed.
+	///
+	/// There is currently no support for random access to tar archives.
+	/// However, it seems that subclassing TarArchive, and using the
+	/// TarBuffer.CurrentRecord and TarBuffer.CurrentBlock
+	/// properties, this would be rather trivial.
+	/// </summary>
+	public class TarArchive : IDisposable
+	{
+		/// <summary>
+		/// Client hook allowing detailed information to be reported during processing
+		/// </summary>
+		public event ProgressMessageHandler ProgressMessageEvent;
+
+		/// <summary>
+		/// Raises the ProgressMessage event
+		/// </summary>
+		/// <param name="entry">The <see cref="TarEntry">TarEntry</see> for this event</param>
+		/// <param name="message">message for this event.  Null is no message</param>
+		protected virtual void OnProgressMessageEvent(TarEntry entry, string message)
+		{
+			ProgressMessageHandler handler = ProgressMessageEvent;
+			if (handler != null)
+			{
+				handler(this, entry, message);
+			}
+		}
+
+		#region Constructors
+
+		/// <summary>
+		/// Constructor for a default <see cref="TarArchive"/>.
+		/// </summary>
+		protected TarArchive()
+		{
+		}
+
+		/// <summary>
+		/// Initalise a TarArchive for input.
+		/// </summary>
+		/// <param name="stream">The <see cref="TarInputStream"/> to use for input.</param>
+		protected TarArchive(TarInputStream stream)
+		{
+			if (stream == null)
+			{
+				throw new ArgumentNullException(nameof(stream));
+			}
+
+			tarIn = stream;
+		}
+
+		/// <summary>
+		/// Initialise a TarArchive for output.
+		/// </summary>
+		/// <param name="stream">The <see cref="TarOutputStream"/> to use for output.</param>
+		protected TarArchive(TarOutputStream stream)
+		{
+			if (stream == null)
+			{
+				throw new ArgumentNullException(nameof(stream));
+			}
+
+			tarOut = stream;
+		}
+
+		#endregion Constructors
+
+		#region Static factory methods
+
+		/// <summary>
+		/// The InputStream based constructors create a TarArchive for the
+		/// purposes of extracting or listing a tar archive. Thus, use
+		/// these constructors when you wish to extract files from or list
+		/// the contents of an existing tar archive.
+		/// </summary>
+		/// <param name="inputStream">The stream to retrieve archive data from.</param>
+		/// <returns>Returns a new <see cref="TarArchive"/> suitable for reading from.</returns>
+		public static TarArchive CreateInputTarArchive(Stream inputStream)
+		{
+			if (inputStream == null)
+			{
+				throw new ArgumentNullException(nameof(inputStream));
+			}
+
+			var tarStream = inputStream as TarInputStream;
+
+			TarArchive result;
+			if (tarStream != null)
+			{
+				result = new TarArchive(tarStream);
+			}
+			else
+			{
+				result = CreateInputTarArchive(inputStream, TarBuffer.DefaultBlockFactor);
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Create TarArchive for reading setting block factor
+		/// </summary>
+		/// <param name="inputStream">A stream containing the tar archive contents</param>
+		/// <param name="blockFactor">The blocking factor to apply</param>
+		/// <returns>Returns a <see cref="TarArchive"/> suitable for reading.</returns>
+		public static TarArchive CreateInputTarArchive(Stream inputStream, int blockFactor)
+		{
+			if (inputStream == null)
+			{
+				throw new ArgumentNullException(nameof(inputStream));
+			}
+
+			if (inputStream is TarInputStream)
+			{
+				throw new ArgumentException("TarInputStream not valid");
+			}
+
+			return new TarArchive(new TarInputStream(inputStream, blockFactor));
+		}
+
+		/// <summary>
+		/// Create a TarArchive for writing to, using the default blocking factor
+		/// </summary>
+		/// <param name="outputStream">The <see cref="Stream"/> to write to</param>
+		/// <returns>Returns a <see cref="TarArchive"/> suitable for writing.</returns>
+		public static TarArchive CreateOutputTarArchive(Stream outputStream)
+		{
+			if (outputStream == null)
+			{
+				throw new ArgumentNullException(nameof(outputStream));
+			}
+
+			var tarStream = outputStream as TarOutputStream;
+
+			TarArchive result;
+			if (tarStream != null)
+			{
+				result = new TarArchive(tarStream);
+			}
+			else
+			{
+				result = CreateOutputTarArchive(outputStream, TarBuffer.DefaultBlockFactor);
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Create a <see cref="TarArchive">tar archive</see> for writing.
+		/// </summary>
+		/// <param name="outputStream">The stream to write to</param>
+		/// <param name="blockFactor">The blocking factor to use for buffering.</param>
+		/// <returns>Returns a <see cref="TarArchive"/> suitable for writing.</returns>
+		public static TarArchive CreateOutputTarArchive(Stream outputStream, int blockFactor)
+		{
+			if (outputStream == null)
+			{
+				throw new ArgumentNullException(nameof(outputStream));
+			}
+
+			if (outputStream is TarOutputStream)
+			{
+				throw new ArgumentException("TarOutputStream is not valid");
+			}
+
+			return new TarArchive(new TarOutputStream(outputStream, blockFactor));
+		}
+
+		#endregion Static factory methods
+
+		/// <summary>
+		/// Set the flag that determines whether existing files are
+		/// kept, or overwritten during extraction.
+		/// </summary>
+		/// <param name="keepExistingFiles">
+		/// If true, do not overwrite existing files.
+		/// </param>
+		public void SetKeepOldFiles(bool keepExistingFiles)
+		{
+			if (isDisposed)
+			{
+				throw new ObjectDisposedException("TarArchive");
+			}
+
+			keepOldFiles = keepExistingFiles;
+		}
+
+		/// <summary>
+		/// Get/set the ascii file translation flag. If ascii file translation
+		/// is true, then the file is checked to see if it a binary file or not.
+		/// If the flag is true and the test indicates it is ascii text
+		/// file, it will be translated. The translation converts the local
+		/// operating system's concept of line ends into the UNIX line end,
+		/// '\n', which is the defacto standard for a TAR archive. This makes
+		/// text files compatible with UNIX.
+		/// </summary>
+		public bool AsciiTranslate
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				return asciiTranslate;
+			}
+
+			set
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				asciiTranslate = value;
+			}
+		}
+
+		/// <summary>
+		/// Set the ascii file translation flag.
+		/// </summary>
+		/// <param name= "translateAsciiFiles">
+		/// If true, translate ascii text files.
+		/// </param>
+		[Obsolete("Use the AsciiTranslate property")]
+		public void SetAsciiTranslation(bool translateAsciiFiles)
+		{
+			if (isDisposed)
+			{
+				throw new ObjectDisposedException("TarArchive");
+			}
+
+			asciiTranslate = translateAsciiFiles;
+		}
+
+		/// <summary>
+		/// PathPrefix is added to entry names as they are written if the value is not null.
+		/// A slash character is appended after PathPrefix
+		/// </summary>
+		public string PathPrefix
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				return pathPrefix;
+			}
+
+			set
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				pathPrefix = value;
+			}
+		}
+
+		/// <summary>
+		/// RootPath is removed from entry names if it is found at the
+		/// beginning of the name.
+		/// </summary>
+		public string RootPath
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				return rootPath;
+			}
+
+			set
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+				// Convert to forward slashes for matching. Trim trailing / for correct final path
+				rootPath = value.Replace('\\', '/').TrimEnd('/');
+			}
+		}
+
+		/// <summary>
+		/// Set user and group information that will be used to fill in the
+		/// tar archive's entry headers. This information is based on that available
+		/// for the linux operating system, which is not always available on other
+		/// operating systems.  TarArchive allows the programmer to specify values
+		/// to be used in their place.
+		/// <see cref="ApplyUserInfoOverrides"/> is set to true by this call.
+		/// </summary>
+		/// <param name="userId">
+		/// The user id to use in the headers.
+		/// </param>
+		/// <param name="userName">
+		/// The user name to use in the headers.
+		/// </param>
+		/// <param name="groupId">
+		/// The group id to use in the headers.
+		/// </param>
+		/// <param name="groupName">
+		/// The group name to use in the headers.
+		/// </param>
+		public void SetUserInfo(int userId, string userName, int groupId, string groupName)
+		{
+			if (isDisposed)
+			{
+				throw new ObjectDisposedException("TarArchive");
+			}
+
+			this.userId = userId;
+			this.userName = userName;
+			this.groupId = groupId;
+			this.groupName = groupName;
+			applyUserInfoOverrides = true;
+		}
+
+		/// <summary>
+		/// Get or set a value indicating if overrides defined by <see cref="SetUserInfo">SetUserInfo</see> should be applied.
+		/// </summary>
+		/// <remarks>If overrides are not applied then the values as set in each header will be used.</remarks>
+		public bool ApplyUserInfoOverrides
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				return applyUserInfoOverrides;
+			}
+
+			set
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				applyUserInfoOverrides = value;
+			}
+		}
+
+		/// <summary>
+		/// Get the archive user id.
+		/// See <see cref="ApplyUserInfoOverrides">ApplyUserInfoOverrides</see> for detail
+		/// on how to allow setting values on a per entry basis.
+		/// </summary>
+		/// <returns>
+		/// The current user id.
+		/// </returns>
+		public int UserId
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				return userId;
+			}
+		}
+
+		/// <summary>
+		/// Get the archive user name.
+		/// See <see cref="ApplyUserInfoOverrides">ApplyUserInfoOverrides</see> for detail
+		/// on how to allow setting values on a per entry basis.
+		/// </summary>
+		/// <returns>
+		/// The current user name.
+		/// </returns>
+		public string UserName
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				return userName;
+			}
+		}
+
+		/// <summary>
+		/// Get the archive group id.
+		/// See <see cref="ApplyUserInfoOverrides">ApplyUserInfoOverrides</see> for detail
+		/// on how to allow setting values on a per entry basis.
+		/// </summary>
+		/// <returns>
+		/// The current group id.
+		/// </returns>
+		public int GroupId
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				return groupId;
+			}
+		}
+
+		/// <summary>
+		/// Get the archive group name.
+		/// See <see cref="ApplyUserInfoOverrides">ApplyUserInfoOverrides</see> for detail
+		/// on how to allow setting values on a per entry basis.
+		/// </summary>
+		/// <returns>
+		/// The current group name.
+		/// </returns>
+		public string GroupName
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				return groupName;
+			}
+		}
+
+		/// <summary>
+		/// Get the archive's record size. Tar archives are composed of
+		/// a series of RECORDS each containing a number of BLOCKS.
+		/// This allowed tar archives to match the IO characteristics of
+		/// the physical device being used. Archives are expected
+		/// to be properly "blocked".
+		/// </summary>
+		/// <returns>
+		/// The record size this archive is using.
+		/// </returns>
+		public int RecordSize
+		{
+			get
+			{
+				if (isDisposed)
+				{
+					throw new ObjectDisposedException("TarArchive");
+				}
+
+				if (tarIn != null)
+				{
+					return tarIn.RecordSize;
+				}
+				else if (tarOut != null)
+				{
+					return tarOut.RecordSize;
+				}
+				return TarBuffer.DefaultRecordSize;
+			}
+		}
+
+		/// <summary>
+		/// Sets the IsStreamOwner property on the underlying stream.
+		/// Set this to false to prevent the Close of the TarArchive from closing the stream.
+		/// </summary>
+		public bool IsStreamOwner
+		{
+			set
+			{
+				if (tarIn != null)
+				{
+					tarIn.IsStreamOwner = value;
+				}
+				else
+				{
+					tarOut.IsStreamOwner = value;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Close the archive.
+		/// </summary>
+		[Obsolete("Use Close instead")]
+		public void CloseArchive()
+		{
+			Close();
+		}
+
+		/// <summary>
+		/// Perform the "list" command for the archive contents.
+		///
+		/// NOTE That this method uses the <see cref="ProgressMessageEvent"> progress event</see> to actually list
+		/// the contents. If the progress display event is not set, nothing will be listed!
+		/// </summary>
+		public void ListContents()
+		{
+			if (isDisposed)
+			{
+				throw new ObjectDisposedException("TarArchive");
+			}
+
+			while (true)
+			{
+				TarEntry entry = tarIn.GetNextEntry();
+
+				if (entry == null)
+				{
+					break;
+				}
+				OnProgressMessageEvent(entry, null);
+			}
+		}
+
+		/// <summary>
+		/// Perform the "extract" command and extract the contents of the archive.
+		/// </summary>
+		/// <param name="destinationDirectory">
+		/// The destination directory into which to extract.
+		/// </param>
+		public void ExtractContents(string destinationDirectory)
+		{
+			if (isDisposed)
+			{
+				throw new ObjectDisposedException("TarArchive");
+			}
+
+			while (true)
+			{
+				TarEntry entry = tarIn.GetNextEntry();
+
+				if (entry == null)
+				{
+					break;
+				}
+
+				if (entry.TarHeader.TypeFlag == TarHeader.LF_LINK || entry.TarHeader.TypeFlag == TarHeader.LF_SYMLINK)
+					continue;
+
+				ExtractEntry(destinationDirectory, entry);
+			}
+		}
+
+		/// <summary>
+		/// Extract an entry from the archive. This method assumes that the
+		/// tarIn stream has been properly set with a call to GetNextEntry().
+		/// </summary>
+		/// <param name="destDir">
+		/// The destination directory into which to extract.
+		/// </param>
+		/// <param name="entry">
+		/// The TarEntry returned by tarIn.GetNextEntry().
+		/// </param>
+		private void ExtractEntry(string destDir, TarEntry entry)
+		{
+			OnProgressMessageEvent(entry, null);
+
+			string name = entry.Name;
+
+			if (Path.IsPathRooted(name))
+			{
+				// NOTE:
+				// for UNC names...  \\machine\share\zoom\beet.txt gives \zoom\beet.txt
+				name = name.Substring(Path.GetPathRoot(name).Length);
+			}
+
+			name = name.Replace('/', Path.DirectorySeparatorChar);
+
+			string destFile = Path.Combine(destDir, name);
+
+			if (entry.IsDirectory)
+			{
+				EnsureDirectoryExists(destFile);
+			}
+			else
+			{
+				string parentDirectory = Path.GetDirectoryName(destFile);
+				EnsureDirectoryExists(parentDirectory);
+
+				bool process = true;
+				var fileInfo = new FileInfo(destFile);
+				if (fileInfo.Exists)
+				{
+					if (keepOldFiles)
+					{
+						OnProgressMessageEvent(entry, "Destination file already exists");
+						process = false;
+					}
+					else if ((fileInfo.Attributes & FileAttributes.ReadOnly) != 0)
+					{
+						OnProgressMessageEvent(entry, "Destination file already exists, and is read-only");
+						process = false;
+					}
+				}
+
+				if (process)
+				{
+					bool asciiTrans = false;
+
+					Stream outputStream = File.Create(destFile);
+					if (this.asciiTranslate)
+					{
+						asciiTrans = !IsBinary(destFile);
+					}
+
+					StreamWriter outw = null;
+					if (asciiTrans)
+					{
+						outw = new StreamWriter(outputStream);
+					}
+
+					byte[] rdbuf = new byte[32 * 1024];
+
+					while (true)
+					{
+						int numRead = tarIn.Read(rdbuf, 0, rdbuf.Length);
+
+						if (numRead <= 0)
+						{
+							break;
+						}
+
+						if (asciiTrans)
+						{
+							for (int off = 0, b = 0; b < numRead; ++b)
+							{
+								if (rdbuf[b] == 10)
+								{
+									string s = Encoding.ASCII.GetString(rdbuf, off, (b - off));
+									outw.WriteLine(s);
+									off = b + 1;
+								}
+							}
+						}
+						else
+						{
+							outputStream.Write(rdbuf, 0, numRead);
+						}
+					}
+
+					if (asciiTrans)
+					{
+						outw.Dispose();
+					}
+					else
+					{
+						outputStream.Dispose();
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// Write an entry to the archive. This method will call the putNextEntry
+		/// and then write the contents of the entry, and finally call closeEntry()
+		/// for entries that are files. For directories, it will call putNextEntry(),
+		/// and then, if the recurse flag is true, process each entry that is a
+		/// child of the directory.
+		/// </summary>
+		/// <param name="sourceEntry">
+		/// The TarEntry representing the entry to write to the archive.
+		/// </param>
+		/// <param name="recurse">
+		/// If true, process the children of directory entries.
+		/// </param>
+		public void WriteEntry(TarEntry sourceEntry, bool recurse)
+		{
+			if (sourceEntry == null)
+			{
+				throw new ArgumentNullException(nameof(sourceEntry));
+			}
+
+			if (isDisposed)
+			{
+				throw new ObjectDisposedException("TarArchive");
+			}
+
+			try
+			{
+				if (recurse)
+				{
+					TarHeader.SetValueDefaults(sourceEntry.UserId, sourceEntry.UserName,
+											   sourceEntry.GroupId, sourceEntry.GroupName);
+				}
+				WriteEntryCore(sourceEntry, recurse);
+			}
+			finally
+			{
+				if (recurse)
+				{
+					TarHeader.RestoreSetValues();
+				}
+			}
+		}
+
+		/// <summary>
+		/// Write an entry to the archive. This method will call the putNextEntry
+		/// and then write the contents of the entry, and finally call closeEntry()
+		/// for entries that are files. For directories, it will call putNextEntry(),
+		/// and then, if the recurse flag is true, process each entry that is a
+		/// child of the directory.
+		/// </summary>
+		/// <param name="sourceEntry">
+		/// The TarEntry representing the entry to write to the archive.
+		/// </param>
+		/// <param name="recurse">
+		/// If true, process the children of directory entries.
+		/// </param>
+		private void WriteEntryCore(TarEntry sourceEntry, bool recurse)
+		{
+			string tempFileName = null;
+			string entryFilename = sourceEntry.File;
+
+			var entry = (TarEntry)sourceEntry.Clone();
+
+			if (applyUserInfoOverrides)
+			{
+				entry.GroupId = groupId;
+				entry.GroupName = groupName;
+				entry.UserId = userId;
+				entry.UserName = userName;
+			}
+
+			OnProgressMessageEvent(entry, null);
+
+			if (asciiTranslate && !entry.IsDirectory)
+			{
+				if (!IsBinary(entryFilename))
+				{
+					tempFileName = Path.GetTempFileName();
+
+					using (StreamReader inStream = File.OpenText(entryFilename))
+					{
+						using (Stream outStream = File.Create(tempFileName))
+						{
+							while (true)
+							{
+								string line = inStream.ReadLine();
+								if (line == null)
+								{
+									break;
+								}
+								byte[] data = Encoding.ASCII.GetBytes(line);
+								outStream.Write(data, 0, data.Length);
+								outStream.WriteByte((byte)'\n');
+							}
+
+							outStream.Flush();
+						}
+					}
+
+					entry.Size = new FileInfo(tempFileName).Length;
+					entryFilename = tempFileName;
+				}
+			}
+
+			string newName = null;
+
+			if (rootPath != null)
+			{
+				if (entry.Name.StartsWith(rootPath, StringComparison.OrdinalIgnoreCase))
+				{
+					newName = entry.Name.Substring(rootPath.Length + 1);
+				}
+			}
+
+			if (pathPrefix != null)
+			{
+				newName = (newName == null) ? pathPrefix + "/" + entry.Name : pathPrefix + "/" + newName;
+			}
+
+			if (newName != null)
+			{
+				entry.Name = newName;
+			}
+
+			tarOut.PutNextEntry(entry);
+
+			if (entry.IsDirectory)
+			{
+				if (recurse)
+				{
+					TarEntry[] list = entry.GetDirectoryEntries();
+					for (int i = 0; i < list.Length; ++i)
+					{
+						WriteEntryCore(list[i], recurse);
+					}
+				}
+			}
+			else
+			{
+				using (Stream inputStream = File.OpenRead(entryFilename))
+				{
+					byte[] localBuffer = new byte[32 * 1024];
+					while (true)
+					{
+						int numRead = inputStream.Read(localBuffer, 0, localBuffer.Length);
+
+						if (numRead <= 0)
+						{
+							break;
+						}
+
+						tarOut.Write(localBuffer, 0, numRead);
+					}
+				}
+
+				if (!string.IsNullOrEmpty(tempFileName))
+				{
+					File.Delete(tempFileName);
+				}
+
+				tarOut.CloseEntry();
+			}
+		}
+
+		/// <summary>
+		/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+		/// </summary>
+		public void Dispose()
+		{
+			Dispose(true);
+			GC.SuppressFinalize(this);
+		}
+
+		/// <summary>
+		/// Releases the unmanaged resources used by the FileStream and optionally releases the managed resources.
+		/// </summary>
+		/// <param name="disposing">true to release both managed and unmanaged resources;
+		/// false to release only unmanaged resources.</param>
+		protected virtual void Dispose(bool disposing)
+		{
+			if (!isDisposed)
+			{
+				isDisposed = true;
+				if (disposing)
+				{
+					if (tarOut != null)
+					{
+						tarOut.Flush();
+						tarOut.Dispose();
+					}
+
+					if (tarIn != null)
+					{
+						tarIn.Dispose();
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// Closes the archive and releases any associated resources.
+		/// </summary>
+		public virtual void Close()
+		{
+			Dispose(true);
+		}
+
+		/// <summary>
+		/// Ensures that resources are freed and other cleanup operations are performed
+		/// when the garbage collector reclaims the <see cref="TarArchive"/>.
+		/// </summary>
+		~TarArchive()
+		{
+			Dispose(false);
+		}
+
+		private static void EnsureDirectoryExists(string directoryName)
+		{
+			if (!Directory.Exists(directoryName))
+			{
+				try
+				{
+					Directory.CreateDirectory(directoryName);
+				}
+				catch (Exception e)
+				{
+					throw new TarException("Exception creating directory '" + directoryName + "', " + e.Message, e);
+				}
+			}
+		}
+
+		// TODO: TarArchive - Is there a better way to test for a text file?
+		// It no longer reads entire files into memory but is still a weak test!
+		// This assumes that byte values 0-7, 14-31 or 255 are binary
+		// and that all non text files contain one of these values
+		private static bool IsBinary(string filename)
+		{
+			using (FileStream fs = File.OpenRead(filename))
+			{
+				int sampleSize = Math.Min(4096, (int)fs.Length);
+				byte[] content = new byte[sampleSize];
+
+				int bytesRead = fs.Read(content, 0, sampleSize);
+
+				for (int i = 0; i < bytesRead; ++i)
+				{
+					byte b = content[i];
+					if ((b < 8) || ((b > 13) && (b < 32)) || (b == 255))
+					{
+						return true;
+					}
+				}
+			}
+			return false;
+		}
+
+		#region Instance Fields
+
+		private bool keepOldFiles;
+		private bool asciiTranslate;
+
+		private int userId;
+		private string userName = string.Empty;
+		private int groupId;
+		private string groupName = string.Empty;
+
+		private string rootPath;
+		private string pathPrefix;
+
+		private bool applyUserInfoOverrides;
+
+		private TarInputStream tarIn;
+		private TarOutputStream tarOut;
+		private bool isDisposed;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Tar/TarBuffer.cs

@@ -0,0 +1,599 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Tar
+{
+	/// <summary>
+	/// The TarBuffer class implements the tar archive concept
+	/// of a buffered input stream. This concept goes back to the
+	/// days of blocked tape drives and special io devices. In the
+	/// C# universe, the only real function that this class
+	/// performs is to ensure that files have the correct "record"
+	/// size, or other tars will complain.
+	/// <p>
+	/// You should never have a need to access this class directly.
+	/// TarBuffers are created by Tar IO Streams.
+	/// </p>
+	/// </summary>
+	public class TarBuffer
+	{
+		/* A quote from GNU tar man file on blocking and records
+		   A `tar' archive file contains a series of blocks.  Each block
+		contains `BLOCKSIZE' bytes.  Although this format may be thought of as
+		being on magnetic tape, other media are often used.
+
+		   Each file archived is represented by a header block which describes
+		the file, followed by zero or more blocks which give the contents of
+		the file.  At the end of the archive file there may be a block filled
+		with binary zeros as an end-of-file marker.  A reasonable system should
+		write a block of zeros at the end, but must not assume that such a
+		block exists when reading an archive.
+
+		   The blocks may be "blocked" for physical I/O operations.  Each
+		record of N blocks is written with a single 'write ()'
+		operation.  On magnetic tapes, the result of such a write is a single
+		record.  When writing an archive, the last record of blocks should be
+		written at the full size, with blocks after the zero block containing
+		all zeros.  When reading an archive, a reasonable system should
+		properly handle an archive whose last record is shorter than the rest,
+		or which contains garbage records after a zero block.
+		*/
+
+		#region Constants
+
+		/// <summary>
+		/// The size of a block in a tar archive in bytes.
+		/// </summary>
+		/// <remarks>This is 512 bytes.</remarks>
+		public const int BlockSize = 512;
+
+		/// <summary>
+		/// The number of blocks in a default record.
+		/// </summary>
+		/// <remarks>
+		/// The default value is 20 blocks per record.
+		/// </remarks>
+		public const int DefaultBlockFactor = 20;
+
+		/// <summary>
+		/// The size in bytes of a default record.
+		/// </summary>
+		/// <remarks>
+		/// The default size is 10KB.
+		/// </remarks>
+		public const int DefaultRecordSize = BlockSize * DefaultBlockFactor;
+
+		#endregion Constants
+
+		/// <summary>
+		/// Get the record size for this buffer
+		/// </summary>
+		/// <value>The record size in bytes.
+		/// This is equal to the <see cref="BlockFactor"/> multiplied by the <see cref="BlockSize"/></value>
+		public int RecordSize
+		{
+			get
+			{
+				return recordSize;
+			}
+		}
+
+		/// <summary>
+		/// Get the TAR Buffer's record size.
+		/// </summary>
+		/// <returns>The record size in bytes.
+		/// This is equal to the <see cref="BlockFactor"/> multiplied by the <see cref="BlockSize"/></returns>
+		[Obsolete("Use RecordSize property instead")]
+		public int GetRecordSize()
+		{
+			return recordSize;
+		}
+
+		/// <summary>
+		/// Get the Blocking factor for the buffer
+		/// </summary>
+		/// <value>This is the number of blocks in each record.</value>
+		public int BlockFactor
+		{
+			get
+			{
+				return blockFactor;
+			}
+		}
+
+		/// <summary>
+		/// Get the TAR Buffer's block factor
+		/// </summary>
+		/// <returns>The block factor; the number of blocks per record.</returns>
+		[Obsolete("Use BlockFactor property instead")]
+		public int GetBlockFactor()
+		{
+			return blockFactor;
+		}
+
+		/// <summary>
+		/// Construct a default TarBuffer
+		/// </summary>
+		protected TarBuffer()
+		{
+		}
+
+		/// <summary>
+		/// Create TarBuffer for reading with default BlockFactor
+		/// </summary>
+		/// <param name="inputStream">Stream to buffer</param>
+		/// <returns>A new <see cref="TarBuffer"/> suitable for input.</returns>
+		public static TarBuffer CreateInputTarBuffer(Stream inputStream)
+		{
+			if (inputStream == null)
+			{
+				throw new ArgumentNullException(nameof(inputStream));
+			}
+
+			return CreateInputTarBuffer(inputStream, DefaultBlockFactor);
+		}
+
+		/// <summary>
+		/// Construct TarBuffer for reading inputStream setting BlockFactor
+		/// </summary>
+		/// <param name="inputStream">Stream to buffer</param>
+		/// <param name="blockFactor">Blocking factor to apply</param>
+		/// <returns>A new <see cref="TarBuffer"/> suitable for input.</returns>
+		public static TarBuffer CreateInputTarBuffer(Stream inputStream, int blockFactor)
+		{
+			if (inputStream == null)
+			{
+				throw new ArgumentNullException(nameof(inputStream));
+			}
+
+			if (blockFactor <= 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(blockFactor), "Factor cannot be negative");
+			}
+
+			var tarBuffer = new TarBuffer();
+			tarBuffer.inputStream = inputStream;
+			tarBuffer.outputStream = null;
+			tarBuffer.Initialize(blockFactor);
+
+			return tarBuffer;
+		}
+
+		/// <summary>
+		/// Construct TarBuffer for writing with default BlockFactor
+		/// </summary>
+		/// <param name="outputStream">output stream for buffer</param>
+		/// <returns>A new <see cref="TarBuffer"/> suitable for output.</returns>
+		public static TarBuffer CreateOutputTarBuffer(Stream outputStream)
+		{
+			if (outputStream == null)
+			{
+				throw new ArgumentNullException(nameof(outputStream));
+			}
+
+			return CreateOutputTarBuffer(outputStream, DefaultBlockFactor);
+		}
+
+		/// <summary>
+		/// Construct TarBuffer for writing Tar output to streams.
+		/// </summary>
+		/// <param name="outputStream">Output stream to write to.</param>
+		/// <param name="blockFactor">Blocking factor to apply</param>
+		/// <returns>A new <see cref="TarBuffer"/> suitable for output.</returns>
+		public static TarBuffer CreateOutputTarBuffer(Stream outputStream, int blockFactor)
+		{
+			if (outputStream == null)
+			{
+				throw new ArgumentNullException(nameof(outputStream));
+			}
+
+			if (blockFactor <= 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(blockFactor), "Factor cannot be negative");
+			}
+
+			var tarBuffer = new TarBuffer();
+			tarBuffer.inputStream = null;
+			tarBuffer.outputStream = outputStream;
+			tarBuffer.Initialize(blockFactor);
+
+			return tarBuffer;
+		}
+
+		/// <summary>
+		/// Initialization common to all constructors.
+		/// </summary>
+		private void Initialize(int archiveBlockFactor)
+		{
+			blockFactor = archiveBlockFactor;
+			recordSize = archiveBlockFactor * BlockSize;
+			recordBuffer = new byte[RecordSize];
+
+			if (inputStream != null)
+			{
+				currentRecordIndex = -1;
+				currentBlockIndex = BlockFactor;
+			}
+			else
+			{
+				currentRecordIndex = 0;
+				currentBlockIndex = 0;
+			}
+		}
+
+		/// <summary>
+		/// Determine if an archive block indicates End of Archive. End of
+		/// archive is indicated by a block that consists entirely of null bytes.
+		/// All remaining blocks for the record should also be null's
+		/// However some older tars only do a couple of null blocks (Old GNU tar for one)
+		/// and also partial records
+		/// </summary>
+		/// <param name = "block">The data block to check.</param>
+		/// <returns>Returns true if the block is an EOF block; false otherwise.</returns>
+		[Obsolete("Use IsEndOfArchiveBlock instead")]
+		public bool IsEOFBlock(byte[] block)
+		{
+			if (block == null)
+			{
+				throw new ArgumentNullException(nameof(block));
+			}
+
+			if (block.Length != BlockSize)
+			{
+				throw new ArgumentException("block length is invalid");
+			}
+
+			for (int i = 0; i < BlockSize; ++i)
+			{
+				if (block[i] != 0)
+				{
+					return false;
+				}
+			}
+
+			return true;
+		}
+
+		/// <summary>
+		/// Determine if an archive block indicates the End of an Archive has been reached.
+		/// End of archive is indicated by a block that consists entirely of null bytes.
+		/// All remaining blocks for the record should also be null's
+		/// However some older tars only do a couple of null blocks (Old GNU tar for one)
+		/// and also partial records
+		/// </summary>
+		/// <param name = "block">The data block to check.</param>
+		/// <returns>Returns true if the block is an EOF block; false otherwise.</returns>
+		public static bool IsEndOfArchiveBlock(byte[] block)
+		{
+			if (block == null)
+			{
+				throw new ArgumentNullException(nameof(block));
+			}
+
+			if (block.Length != BlockSize)
+			{
+				throw new ArgumentException("block length is invalid");
+			}
+
+			for (int i = 0; i < BlockSize; ++i)
+			{
+				if (block[i] != 0)
+				{
+					return false;
+				}
+			}
+
+			return true;
+		}
+
+		/// <summary>
+		/// Skip over a block on the input stream.
+		/// </summary>
+		public void SkipBlock()
+		{
+			if (inputStream == null)
+			{
+				throw new TarException("no input stream defined");
+			}
+
+			if (currentBlockIndex >= BlockFactor)
+			{
+				if (!ReadRecord())
+				{
+					throw new TarException("Failed to read a record");
+				}
+			}
+
+			currentBlockIndex++;
+		}
+
+		/// <summary>
+		/// Read a block from the input stream.
+		/// </summary>
+		/// <returns>
+		/// The block of data read.
+		/// </returns>
+		public byte[] ReadBlock()
+		{
+			if (inputStream == null)
+			{
+				throw new TarException("TarBuffer.ReadBlock - no input stream defined");
+			}
+
+			if (currentBlockIndex >= BlockFactor)
+			{
+				if (!ReadRecord())
+				{
+					throw new TarException("Failed to read a record");
+				}
+			}
+
+			byte[] result = new byte[BlockSize];
+
+			Array.Copy(recordBuffer, (currentBlockIndex * BlockSize), result, 0, BlockSize);
+			currentBlockIndex++;
+			return result;
+		}
+
+		/// <summary>
+		/// Read a record from data stream.
+		/// </summary>
+		/// <returns>
+		/// false if End-Of-File, else true.
+		/// </returns>
+		private bool ReadRecord()
+		{
+			if (inputStream == null)
+			{
+				throw new TarException("no input stream stream defined");
+			}
+
+			currentBlockIndex = 0;
+
+			int offset = 0;
+			int bytesNeeded = RecordSize;
+
+			while (bytesNeeded > 0)
+			{
+				long numBytes = inputStream.Read(recordBuffer, offset, bytesNeeded);
+
+				//
+				// NOTE
+				// We have found EOF, and the record is not full!
+				//
+				// This is a broken archive. It does not follow the standard
+				// blocking algorithm. However, because we are generous, and
+				// it requires little effort, we will simply ignore the error
+				// and continue as if the entire record were read. This does
+				// not appear to break anything upstream. We used to return
+				// false in this case.
+				//
+				// Thanks to 'Yohann.Roussel@alcatel.fr' for this fix.
+				//
+				if (numBytes <= 0)
+				{
+					break;
+				}
+
+				offset += (int)numBytes;
+				bytesNeeded -= (int)numBytes;
+			}
+
+			currentRecordIndex++;
+			return true;
+		}
+
+		/// <summary>
+		/// Get the current block number, within the current record, zero based.
+		/// </summary>
+		/// <remarks>Block numbers are zero based values</remarks>
+		/// <seealso cref="RecordSize"/>
+		public int CurrentBlock
+		{
+			get { return currentBlockIndex; }
+		}
+
+		/// <summary>
+		/// Gets or sets a flag indicating ownership of underlying stream.
+		/// When the flag is true <see cref="Close" /> will close the underlying stream also.
+		/// </summary>
+		/// <remarks>The default value is true.</remarks>
+		public bool IsStreamOwner { get; set; } = true;
+
+		/// <summary>
+		/// Get the current block number, within the current record, zero based.
+		/// </summary>
+		/// <returns>
+		/// The current zero based block number.
+		/// </returns>
+		/// <remarks>
+		/// The absolute block number = (<see cref="GetCurrentRecordNum">record number</see> * <see cref="BlockFactor">block factor</see>) + <see cref="GetCurrentBlockNum">block number</see>.
+		/// </remarks>
+		[Obsolete("Use CurrentBlock property instead")]
+		public int GetCurrentBlockNum()
+		{
+			return currentBlockIndex;
+		}
+
+		/// <summary>
+		/// Get the current record number.
+		/// </summary>
+		/// <returns>
+		/// The current zero based record number.
+		/// </returns>
+		public int CurrentRecord
+		{
+			get { return currentRecordIndex; }
+		}
+
+		/// <summary>
+		/// Get the current record number.
+		/// </summary>
+		/// <returns>
+		/// The current zero based record number.
+		/// </returns>
+		[Obsolete("Use CurrentRecord property instead")]
+		public int GetCurrentRecordNum()
+		{
+			return currentRecordIndex;
+		}
+
+		/// <summary>
+		/// Write a block of data to the archive.
+		/// </summary>
+		/// <param name="block">
+		/// The data to write to the archive.
+		/// </param>
+		public void WriteBlock(byte[] block)
+		{
+			if (block == null)
+			{
+				throw new ArgumentNullException(nameof(block));
+			}
+
+			if (outputStream == null)
+			{
+				throw new TarException("TarBuffer.WriteBlock - no output stream defined");
+			}
+
+			if (block.Length != BlockSize)
+			{
+				string errorText = string.Format("TarBuffer.WriteBlock - block to write has length '{0}' which is not the block size of '{1}'",
+					block.Length, BlockSize);
+				throw new TarException(errorText);
+			}
+
+			if (currentBlockIndex >= BlockFactor)
+			{
+				WriteRecord();
+			}
+
+			Array.Copy(block, 0, recordBuffer, (currentBlockIndex * BlockSize), BlockSize);
+			currentBlockIndex++;
+		}
+
+		/// <summary>
+		/// Write an archive record to the archive, where the record may be
+		/// inside of a larger array buffer. The buffer must be "offset plus
+		/// record size" long.
+		/// </summary>
+		/// <param name="buffer">
+		/// The buffer containing the record data to write.
+		/// </param>
+		/// <param name="offset">
+		/// The offset of the record data within buffer.
+		/// </param>
+		public void WriteBlock(byte[] buffer, int offset)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			if (outputStream == null)
+			{
+				throw new TarException("TarBuffer.WriteBlock - no output stream stream defined");
+			}
+
+			if ((offset < 0) || (offset >= buffer.Length))
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset));
+			}
+
+			if ((offset + BlockSize) > buffer.Length)
+			{
+				string errorText = string.Format("TarBuffer.WriteBlock - record has length '{0}' with offset '{1}' which is less than the record size of '{2}'",
+					buffer.Length, offset, recordSize);
+				throw new TarException(errorText);
+			}
+
+			if (currentBlockIndex >= BlockFactor)
+			{
+				WriteRecord();
+			}
+
+			Array.Copy(buffer, offset, recordBuffer, (currentBlockIndex * BlockSize), BlockSize);
+
+			currentBlockIndex++;
+		}
+
+		/// <summary>
+		/// Write a TarBuffer record to the archive.
+		/// </summary>
+		private void WriteRecord()
+		{
+			if (outputStream == null)
+			{
+				throw new TarException("TarBuffer.WriteRecord no output stream defined");
+			}
+
+			outputStream.Write(recordBuffer, 0, RecordSize);
+			outputStream.Flush();
+
+			currentBlockIndex = 0;
+			currentRecordIndex++;
+		}
+
+		/// <summary>
+		/// WriteFinalRecord writes the current record buffer to output any unwritten data is present.
+		/// </summary>
+		/// <remarks>Any trailing bytes are set to zero which is by definition correct behaviour
+		/// for the end of a tar stream.</remarks>
+		private void WriteFinalRecord()
+		{
+			if (outputStream == null)
+			{
+				throw new TarException("TarBuffer.WriteFinalRecord no output stream defined");
+			}
+
+			if (currentBlockIndex > 0)
+			{
+				int dataBytes = currentBlockIndex * BlockSize;
+				Array.Clear(recordBuffer, dataBytes, RecordSize - dataBytes);
+				WriteRecord();
+			}
+
+			outputStream.Flush();
+		}
+
+		/// <summary>
+		/// Close the TarBuffer. If this is an output buffer, also flush the
+		/// current block before closing.
+		/// </summary>
+		public void Close()
+		{
+			if (outputStream != null)
+			{
+				WriteFinalRecord();
+
+				if (IsStreamOwner)
+				{
+					outputStream.Dispose();
+				}
+				outputStream = null;
+			}
+			else if (inputStream != null)
+			{
+				if (IsStreamOwner)
+				{
+					inputStream.Dispose();
+				}
+				inputStream = null;
+			}
+		}
+
+		#region Instance Fields
+
+		private Stream inputStream;
+		private Stream outputStream;
+
+		private byte[] recordBuffer;
+		private int currentBlockIndex;
+		private int currentRecordIndex;
+
+		private int recordSize = DefaultRecordSize;
+		private int blockFactor = DefaultBlockFactor;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Tar/TarEntry.cs

@@ -0,0 +1,547 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Tar
+{
+	/// <summary>
+	/// This class represents an entry in a Tar archive. It consists
+	/// of the entry's header, as well as the entry's File. Entries
+	/// can be instantiated in one of three ways, depending on how
+	/// they are to be used.
+	/// <p>
+	/// TarEntries that are created from the header bytes read from
+	/// an archive are instantiated with the TarEntry( byte[] )
+	/// constructor. These entries will be used when extracting from
+	/// or listing the contents of an archive. These entries have their
+	/// header filled in using the header bytes. They also set the File
+	/// to null, since they reference an archive entry not a file.</p>
+	/// <p>
+	/// TarEntries that are created from files that are to be written
+	/// into an archive are instantiated with the CreateEntryFromFile(string)
+	/// pseudo constructor. These entries have their header filled in using
+	/// the File's information. They also keep a reference to the File
+	/// for convenience when writing entries.</p>
+	/// <p>
+	/// Finally, TarEntries can be constructed from nothing but a name.
+	/// This allows the programmer to construct the entry by hand, for
+	/// instance when only an InputStream is available for writing to
+	/// the archive, and the header information is constructed from
+	/// other information. In this case the header fields are set to
+	/// defaults and the File is set to null.</p>
+	/// <see cref="TarHeader"/>
+	/// </summary>
+	public class TarEntry
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a default instance of <see cref="TarEntry"/>.
+		/// </summary>
+		private TarEntry()
+		{
+			header = new TarHeader();
+		}
+
+		/// <summary>
+		/// Construct an entry from an archive's header bytes. File is set
+		/// to null.
+		/// </summary>
+		/// <param name = "headerBuffer">
+		/// The header bytes from a tar archive entry.
+		/// </param>
+		public TarEntry(byte[] headerBuffer)
+		{
+			header = new TarHeader();
+			header.ParseBuffer(headerBuffer);
+		}
+
+		/// <summary>
+		/// Construct a TarEntry using the <paramref name="header">header</paramref> provided
+		/// </summary>
+		/// <param name="header">Header details for entry</param>
+		public TarEntry(TarHeader header)
+		{
+			if (header == null)
+			{
+				throw new ArgumentNullException(nameof(header));
+			}
+
+			this.header = (TarHeader)header.Clone();
+		}
+
+		#endregion Constructors
+
+		#region ICloneable Members
+
+		/// <summary>
+		/// Clone this tar entry.
+		/// </summary>
+		/// <returns>Returns a clone of this entry.</returns>
+		public object Clone()
+		{
+			var entry = new TarEntry();
+			entry.file = file;
+			entry.header = (TarHeader)header.Clone();
+			entry.Name = Name;
+			return entry;
+		}
+
+		#endregion ICloneable Members
+
+		/// <summary>
+		/// Construct an entry with only a <paramref name="name">name</paramref>.
+		/// This allows the programmer to construct the entry's header "by hand".
+		/// </summary>
+		/// <param name="name">The name to use for the entry</param>
+		/// <returns>Returns the newly created <see cref="TarEntry"/></returns>
+		public static TarEntry CreateTarEntry(string name)
+		{
+			var entry = new TarEntry();
+			TarEntry.NameTarHeader(entry.header, name);
+			return entry;
+		}
+
+		/// <summary>
+		/// Construct an entry for a file. File is set to file, and the
+		/// header is constructed from information from the file.
+		/// </summary>
+		/// <param name = "fileName">The file name that the entry represents.</param>
+		/// <returns>Returns the newly created <see cref="TarEntry"/></returns>
+		public static TarEntry CreateEntryFromFile(string fileName)
+		{
+			var entry = new TarEntry();
+			entry.GetFileTarHeader(entry.header, fileName);
+			return entry;
+		}
+
+		/// <summary>
+		/// Determine if the two entries are equal. Equality is determined
+		/// by the header names being equal.
+		/// </summary>
+		/// <param name="obj">The <see cref="Object"/> to compare with the current Object.</param>
+		/// <returns>
+		/// True if the entries are equal; false if not.
+		/// </returns>
+		public override bool Equals(object obj)
+		{
+			var localEntry = obj as TarEntry;
+
+			if (localEntry != null)
+			{
+				return Name.Equals(localEntry.Name);
+			}
+			return false;
+		}
+
+		/// <summary>
+		/// Derive a Hash value for the current <see cref="Object"/>
+		/// </summary>
+		/// <returns>A Hash code for the current <see cref="Object"/></returns>
+		public override int GetHashCode()
+		{
+			return Name.GetHashCode();
+		}
+
+		/// <summary>
+		/// Determine if the given entry is a descendant of this entry.
+		/// Descendancy is determined by the name of the descendant
+		/// starting with this entry's name.
+		/// </summary>
+		/// <param name = "toTest">
+		/// Entry to be checked as a descendent of this.
+		/// </param>
+		/// <returns>
+		/// True if entry is a descendant of this.
+		/// </returns>
+		public bool IsDescendent(TarEntry toTest)
+		{
+			if (toTest == null)
+			{
+				throw new ArgumentNullException(nameof(toTest));
+			}
+
+			return toTest.Name.StartsWith(Name, StringComparison.Ordinal);
+		}
+
+		/// <summary>
+		/// Get this entry's header.
+		/// </summary>
+		/// <returns>
+		/// This entry's TarHeader.
+		/// </returns>
+		public TarHeader TarHeader
+		{
+			get
+			{
+				return header;
+			}
+		}
+
+		/// <summary>
+		/// Get/Set this entry's name.
+		/// </summary>
+		public string Name
+		{
+			get
+			{
+				return header.Name;
+			}
+			set
+			{
+				header.Name = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set this entry's user id.
+		/// </summary>
+		public int UserId
+		{
+			get
+			{
+				return header.UserId;
+			}
+			set
+			{
+				header.UserId = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set this entry's group id.
+		/// </summary>
+		public int GroupId
+		{
+			get
+			{
+				return header.GroupId;
+			}
+			set
+			{
+				header.GroupId = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set this entry's user name.
+		/// </summary>
+		public string UserName
+		{
+			get
+			{
+				return header.UserName;
+			}
+			set
+			{
+				header.UserName = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set this entry's group name.
+		/// </summary>
+		public string GroupName
+		{
+			get
+			{
+				return header.GroupName;
+			}
+			set
+			{
+				header.GroupName = value;
+			}
+		}
+
+		/// <summary>
+		/// Convenience method to set this entry's group and user ids.
+		/// </summary>
+		/// <param name="userId">
+		/// This entry's new user id.
+		/// </param>
+		/// <param name="groupId">
+		/// This entry's new group id.
+		/// </param>
+		public void SetIds(int userId, int groupId)
+		{
+			UserId = userId;
+			GroupId = groupId;
+		}
+
+		/// <summary>
+		/// Convenience method to set this entry's group and user names.
+		/// </summary>
+		/// <param name="userName">
+		/// This entry's new user name.
+		/// </param>
+		/// <param name="groupName">
+		/// This entry's new group name.
+		/// </param>
+		public void SetNames(string userName, string groupName)
+		{
+			UserName = userName;
+			GroupName = groupName;
+		}
+
+		/// <summary>
+		/// Get/Set the modification time for this entry
+		/// </summary>
+		public DateTime ModTime
+		{
+			get
+			{
+				return header.ModTime;
+			}
+			set
+			{
+				header.ModTime = value;
+			}
+		}
+
+		/// <summary>
+		/// Get this entry's file.
+		/// </summary>
+		/// <returns>
+		/// This entry's file.
+		/// </returns>
+		public string File
+		{
+			get
+			{
+				return file;
+			}
+		}
+
+		/// <summary>
+		/// Get/set this entry's recorded file size.
+		/// </summary>
+		public long Size
+		{
+			get
+			{
+				return header.Size;
+			}
+			set
+			{
+				header.Size = value;
+			}
+		}
+
+		/// <summary>
+		/// Return true if this entry represents a directory, false otherwise
+		/// </summary>
+		/// <returns>
+		/// True if this entry is a directory.
+		/// </returns>
+		public bool IsDirectory
+		{
+			get
+			{
+				if (file != null)
+				{
+					return Directory.Exists(file);
+				}
+
+				if (header != null)
+				{
+					if ((header.TypeFlag == TarHeader.LF_DIR) || Name.EndsWith("/", StringComparison.Ordinal))
+					{
+						return true;
+					}
+				}
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// Fill in a TarHeader with information from a File.
+		/// </summary>
+		/// <param name="header">
+		/// The TarHeader to fill in.
+		/// </param>
+		/// <param name="file">
+		/// The file from which to get the header information.
+		/// </param>
+		public void GetFileTarHeader(TarHeader header, string file)
+		{
+			if (header == null)
+			{
+				throw new ArgumentNullException(nameof(header));
+			}
+
+			if (file == null)
+			{
+				throw new ArgumentNullException(nameof(file));
+			}
+
+			this.file = file;
+
+			// bugfix from torhovl from #D forum:
+			string name = file;
+
+			// 23-Jan-2004 GnuTar allows device names in path where the name is not local to the current directory
+			if (name.IndexOf(Directory.GetCurrentDirectory(), StringComparison.Ordinal) == 0)
+			{
+				name = name.Substring(Directory.GetCurrentDirectory().Length);
+			}
+
+			/*
+						if (Path.DirectorySeparatorChar == '\\')
+						{
+							// check if the OS is Windows
+							// Strip off drive letters!
+							if (name.Length > 2)
+							{
+								char ch1 = name[0];
+								char ch2 = name[1];
+
+								if (ch2 == ':' && Char.IsLetter(ch1))
+								{
+									name = name.Substring(2);
+								}
+							}
+						}
+			*/
+
+			name = name.Replace(Path.DirectorySeparatorChar, '/');
+
+			// No absolute pathnames
+			// Windows (and Posix?) paths can start with UNC style "\\NetworkDrive\",
+			// so we loop on starting /'s.
+			while (name.StartsWith("/", StringComparison.Ordinal))
+			{
+				name = name.Substring(1);
+			}
+
+			header.LinkName = String.Empty;
+			header.Name = name;
+
+			if (Directory.Exists(file))
+			{
+				header.Mode = 1003; // Magic number for security access for a UNIX filesystem
+				header.TypeFlag = TarHeader.LF_DIR;
+				if ((header.Name.Length == 0) || header.Name[header.Name.Length - 1] != '/')
+				{
+					header.Name = header.Name + "/";
+				}
+
+				header.Size = 0;
+			}
+			else
+			{
+				header.Mode = 33216; // Magic number for security access for a UNIX filesystem
+				header.TypeFlag = TarHeader.LF_NORMAL;
+				header.Size = new FileInfo(file.Replace('/', Path.DirectorySeparatorChar)).Length;
+			}
+
+			header.ModTime = System.IO.File.GetLastWriteTime(file.Replace('/', Path.DirectorySeparatorChar)).ToUniversalTime();
+			header.DevMajor = 0;
+			header.DevMinor = 0;
+		}
+
+		/// <summary>
+		/// Get entries for all files present in this entries directory.
+		/// If this entry doesnt represent a directory zero entries are returned.
+		/// </summary>
+		/// <returns>
+		/// An array of TarEntry's for this entry's children.
+		/// </returns>
+		public TarEntry[] GetDirectoryEntries()
+		{
+			if ((file == null) || !Directory.Exists(file))
+			{
+				return new TarEntry[0];
+			}
+
+			string[] list = Directory.GetFileSystemEntries(file);
+			TarEntry[] result = new TarEntry[list.Length];
+
+			for (int i = 0; i < list.Length; ++i)
+			{
+				result[i] = TarEntry.CreateEntryFromFile(list[i]);
+			}
+
+			return result;
+		}
+
+		/// <summary>
+		/// Write an entry's header information to a header buffer.
+		/// </summary>
+		/// <param name = "outBuffer">
+		/// The tar entry header buffer to fill in.
+		/// </param>
+		public void WriteEntryHeader(byte[] outBuffer)
+		{
+			header.WriteHeader(outBuffer);
+		}
+
+		/// <summary>
+		/// Convenience method that will modify an entry's name directly
+		/// in place in an entry header buffer byte array.
+		/// </summary>
+		/// <param name="buffer">
+		/// The buffer containing the entry header to modify.
+		/// </param>
+		/// <param name="newName">
+		/// The new name to place into the header buffer.
+		/// </param>
+		static public void AdjustEntryName(byte[] buffer, string newName)
+		{
+			TarHeader.GetNameBytes(newName, buffer, 0, TarHeader.NAMELEN);
+		}
+
+		/// <summary>
+		/// Fill in a TarHeader given only the entry's name.
+		/// </summary>
+		/// <param name="header">
+		/// The TarHeader to fill in.
+		/// </param>
+		/// <param name="name">
+		/// The tar entry name.
+		/// </param>
+		static public void NameTarHeader(TarHeader header, string name)
+		{
+			if (header == null)
+			{
+				throw new ArgumentNullException(nameof(header));
+			}
+
+			if (name == null)
+			{
+				throw new ArgumentNullException(nameof(name));
+			}
+
+			bool isDir = name.EndsWith("/", StringComparison.Ordinal);
+
+			header.Name = name;
+			header.Mode = isDir ? 1003 : 33216;
+			header.UserId = 0;
+			header.GroupId = 0;
+			header.Size = 0;
+
+			header.ModTime = DateTime.UtcNow;
+
+			header.TypeFlag = isDir ? TarHeader.LF_DIR : TarHeader.LF_NORMAL;
+
+			header.LinkName = String.Empty;
+			header.UserName = String.Empty;
+			header.GroupName = String.Empty;
+
+			header.DevMajor = 0;
+			header.DevMinor = 0;
+		}
+
+		#region Instance Fields
+
+		/// <summary>
+		/// The name of the file this entry represents or null if the entry is not based on a file.
+		/// </summary>
+		private string file;
+
+		/// <summary>
+		/// The entry's header information.
+		/// </summary>
+		private TarHeader header;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Tar/TarException.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Tar
+{
+	/// <summary>
+	/// TarException represents exceptions specific to Tar classes and code.
+	/// </summary>
+	public class TarException : SharpZipBaseException
+	{
+		/// <summary>
+		/// Initialise a new instance of <see cref="TarException" />.
+		/// </summary>
+		public TarException()
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="TarException" /> with its message string.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		public TarException(string message)
+			: base(message)
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="TarException" />.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		/// <param name="innerException">The <see cref="Exception"/> that caused this exception.</param>
+		public TarException(string message, Exception innerException)
+			: base(message, innerException)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Tar/TarExtendedHeaderReader.cs

@@ -0,0 +1,99 @@
+using System.Collections.Generic;
+using System.Text;
+
+namespace ICSharpCode.SharpZipLib.Tar
+{
+	/// <summary>
+	/// Reads the extended header of a Tar stream
+	/// </summary>
+	public class TarExtendedHeaderReader
+	{
+		private const byte LENGTH = 0;
+		private const byte KEY = 1;
+		private const byte VALUE = 2;
+		private const byte END = 3;
+
+		private readonly Dictionary<string, string> headers = new Dictionary<string, string>();
+
+		private string[] headerParts = new string[3];
+
+		private int bbIndex;
+		private byte[] byteBuffer;
+		private char[] charBuffer;
+
+		private readonly StringBuilder sb = new StringBuilder();
+		private readonly Decoder decoder = Encoding.UTF8.GetDecoder();
+
+		private int state = LENGTH;
+
+		private static readonly byte[] StateNext = new[] { (byte)' ', (byte)'=', (byte)'\n' };
+
+		/// <summary>
+		/// Creates a new <see cref="TarExtendedHeaderReader"/>.
+		/// </summary>
+		public TarExtendedHeaderReader()
+		{
+			ResetBuffers();
+		}
+
+		/// <summary>
+		/// Read <paramref name="length"/> bytes from <paramref name="buffer"/>
+		/// </summary>
+		/// <param name="buffer"></param>
+		/// <param name="length"></param>
+		public void Read(byte[] buffer, int length)
+		{
+			for (int i = 0; i < length; i++)
+			{
+				byte next = buffer[i];
+
+				if (next == StateNext[state])
+				{
+					Flush();
+					headerParts[state] = sb.ToString();
+					sb.Clear();
+
+					if (++state == END)
+					{
+						headers.Add(headerParts[KEY], headerParts[VALUE]);
+						headerParts = new string[3];
+						state = LENGTH;
+					}
+				}
+				else
+				{
+					byteBuffer[bbIndex++] = next;
+					if (bbIndex == 4)
+						Flush();
+				}
+			}
+		}
+
+		private void Flush()
+		{
+			decoder.Convert(byteBuffer, 0, bbIndex, charBuffer, 0, 4, false, out int bytesUsed, out int charsUsed, out bool completed);
+
+			sb.Append(charBuffer, 0, charsUsed);
+			ResetBuffers();
+		}
+
+		private void ResetBuffers()
+		{
+			charBuffer = new char[4];
+			byteBuffer = new byte[4];
+			bbIndex = 0;
+		}
+
+		/// <summary>
+		/// Returns the parsed headers as key-value strings
+		/// </summary>
+		public Dictionary<string, string> Headers
+		{
+			get
+			{
+				// TODO: Check for invalid state? -NM 2018-07-01
+				return headers;
+			}
+		}
+	}
+}

ICSharpCode.SharpZipLib/Tar/TarInputStream.cs

@@ -0,0 +1,726 @@
+using System;
+using System.IO;
+using System.Text;
+
+namespace ICSharpCode.SharpZipLib.Tar
+{
+	/// <summary>
+	/// The TarInputStream reads a UNIX tar archive as an InputStream.
+	/// methods are provided to position at each successive entry in
+	/// the archive, and the read each entry as a normal input stream
+	/// using read().
+	/// </summary>
+	public class TarInputStream : Stream
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Construct a TarInputStream with default block factor
+		/// </summary>
+		/// <param name="inputStream">stream to source data from</param>
+		public TarInputStream(Stream inputStream)
+			: this(inputStream, TarBuffer.DefaultBlockFactor)
+		{
+		}
+
+		/// <summary>
+		/// Construct a TarInputStream with user specified block factor
+		/// </summary>
+		/// <param name="inputStream">stream to source data from</param>
+		/// <param name="blockFactor">block factor to apply to archive</param>
+		public TarInputStream(Stream inputStream, int blockFactor)
+		{
+			this.inputStream = inputStream;
+			tarBuffer = TarBuffer.CreateInputTarBuffer(inputStream, blockFactor);
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Gets or sets a flag indicating ownership of underlying stream.
+		/// When the flag is true <see cref="Stream.Dispose()" /> will close the underlying stream also.
+		/// </summary>
+		/// <remarks>The default value is true.</remarks>
+		public bool IsStreamOwner
+		{
+			get { return tarBuffer.IsStreamOwner; }
+			set { tarBuffer.IsStreamOwner = value; }
+		}
+
+		#region Stream Overrides
+
+		/// <summary>
+		/// Gets a value indicating whether the current stream supports reading
+		/// </summary>
+		public override bool CanRead
+		{
+			get
+			{
+				return inputStream.CanRead;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether the current stream supports seeking
+		/// This property always returns false.
+		/// </summary>
+		public override bool CanSeek
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating if the stream supports writing.
+		/// This property always returns false.
+		/// </summary>
+		public override bool CanWrite
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// The length in bytes of the stream
+		/// </summary>
+		public override long Length
+		{
+			get
+			{
+				return inputStream.Length;
+			}
+		}
+
+		/// <summary>
+		/// Gets or sets the position within the stream.
+		/// Setting the Position is not supported and throws a NotSupportedExceptionNotSupportedException
+		/// </summary>
+		/// <exception cref="NotSupportedException">Any attempt to set position</exception>
+		public override long Position
+		{
+			get
+			{
+				return inputStream.Position;
+			}
+			set
+			{
+				throw new NotSupportedException("TarInputStream Seek not supported");
+			}
+		}
+
+		/// <summary>
+		/// Flushes the baseInputStream
+		/// </summary>
+		public override void Flush()
+		{
+			inputStream.Flush();
+		}
+
+		/// <summary>
+		/// Set the streams position.  This operation is not supported and will throw a NotSupportedException
+		/// </summary>
+		/// <param name="offset">The offset relative to the origin to seek to.</param>
+		/// <param name="origin">The <see cref="SeekOrigin"/> to start seeking from.</param>
+		/// <returns>The new position in the stream.</returns>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override long Seek(long offset, SeekOrigin origin)
+		{
+			throw new NotSupportedException("TarInputStream Seek not supported");
+		}
+
+		/// <summary>
+		/// Sets the length of the stream
+		/// This operation is not supported and will throw a NotSupportedException
+		/// </summary>
+		/// <param name="value">The new stream length.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void SetLength(long value)
+		{
+			throw new NotSupportedException("TarInputStream SetLength not supported");
+		}
+
+		/// <summary>
+		/// Writes a block of bytes to this stream using data from a buffer.
+		/// This operation is not supported and will throw a NotSupportedException
+		/// </summary>
+		/// <param name="buffer">The buffer containing bytes to write.</param>
+		/// <param name="offset">The offset in the buffer of the frist byte to write.</param>
+		/// <param name="count">The number of bytes to write.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			throw new NotSupportedException("TarInputStream Write not supported");
+		}
+
+		/// <summary>
+		/// Writes a byte to the current position in the file stream.
+		/// This operation is not supported and will throw a NotSupportedException
+		/// </summary>
+		/// <param name="value">The byte value to write.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void WriteByte(byte value)
+		{
+			throw new NotSupportedException("TarInputStream WriteByte not supported");
+		}
+
+		/// <summary>
+		/// Reads a byte from the current tar archive entry.
+		/// </summary>
+		/// <returns>A byte cast to an int; -1 if the at the end of the stream.</returns>
+		public override int ReadByte()
+		{
+			byte[] oneByteBuffer = new byte[1];
+			int num = Read(oneByteBuffer, 0, 1);
+			if (num <= 0)
+			{
+				// return -1 to indicate that no byte was read.
+				return -1;
+			}
+			return oneByteBuffer[0];
+		}
+
+		/// <summary>
+		/// Reads bytes from the current tar archive entry.
+		///
+		/// This method is aware of the boundaries of the current
+		/// entry in the archive and will deal with them appropriately
+		/// </summary>
+		/// <param name="buffer">
+		/// The buffer into which to place bytes read.
+		/// </param>
+		/// <param name="offset">
+		/// The offset at which to place bytes read.
+		/// </param>
+		/// <param name="count">
+		/// The number of bytes to read.
+		/// </param>
+		/// <returns>
+		/// The number of bytes read, or 0 at end of stream/EOF.
+		/// </returns>
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			int totalRead = 0;
+
+			if (entryOffset >= entrySize)
+			{
+				return 0;
+			}
+
+			long numToRead = count;
+
+			if ((numToRead + entryOffset) > entrySize)
+			{
+				numToRead = entrySize - entryOffset;
+			}
+
+			if (readBuffer != null)
+			{
+				int sz = (numToRead > readBuffer.Length) ? readBuffer.Length : (int)numToRead;
+
+				Array.Copy(readBuffer, 0, buffer, offset, sz);
+
+				if (sz >= readBuffer.Length)
+				{
+					readBuffer = null;
+				}
+				else
+				{
+					int newLen = readBuffer.Length - sz;
+					byte[] newBuf = new byte[newLen];
+					Array.Copy(readBuffer, sz, newBuf, 0, newLen);
+					readBuffer = newBuf;
+				}
+
+				totalRead += sz;
+				numToRead -= sz;
+				offset += sz;
+			}
+
+			while (numToRead > 0)
+			{
+				byte[] rec = tarBuffer.ReadBlock();
+				if (rec == null)
+				{
+					// Unexpected EOF!
+					throw new TarException("unexpected EOF with " + numToRead + " bytes unread");
+				}
+
+				var sz = (int)numToRead;
+				int recLen = rec.Length;
+
+				if (recLen > sz)
+				{
+					Array.Copy(rec, 0, buffer, offset, sz);
+					readBuffer = new byte[recLen - sz];
+					Array.Copy(rec, sz, readBuffer, 0, recLen - sz);
+				}
+				else
+				{
+					sz = recLen;
+					Array.Copy(rec, 0, buffer, offset, recLen);
+				}
+
+				totalRead += sz;
+				numToRead -= sz;
+				offset += sz;
+			}
+
+			entryOffset += totalRead;
+
+			return totalRead;
+		}
+
+		/// <summary>
+		/// Closes this stream. Calls the TarBuffer's close() method.
+		/// The underlying stream is closed by the TarBuffer.
+		/// </summary>
+		protected override void Dispose(bool disposing)
+		{
+			if (disposing)
+			{
+				tarBuffer.Close();
+			}
+		}
+
+		#endregion Stream Overrides
+
+		/// <summary>
+		/// Set the entry factory for this instance.
+		/// </summary>
+		/// <param name="factory">The factory for creating new entries</param>
+		public void SetEntryFactory(IEntryFactory factory)
+		{
+			entryFactory = factory;
+		}
+
+		/// <summary>
+		/// Get the record size being used by this stream's TarBuffer.
+		/// </summary>
+		public int RecordSize
+		{
+			get { return tarBuffer.RecordSize; }
+		}
+
+		/// <summary>
+		/// Get the record size being used by this stream's TarBuffer.
+		/// </summary>
+		/// <returns>
+		/// TarBuffer record size.
+		/// </returns>
+		[Obsolete("Use RecordSize property instead")]
+		public int GetRecordSize()
+		{
+			return tarBuffer.RecordSize;
+		}
+
+		/// <summary>
+		/// Get the available data that can be read from the current
+		/// entry in the archive. This does not indicate how much data
+		/// is left in the entire archive, only in the current entry.
+		/// This value is determined from the entry's size header field
+		/// and the amount of data already read from the current entry.
+		/// </summary>
+		/// <returns>
+		/// The number of available bytes for the current entry.
+		/// </returns>
+		public long Available
+		{
+			get
+			{
+				return entrySize - entryOffset;
+			}
+		}
+
+		/// <summary>
+		/// Skip bytes in the input buffer. This skips bytes in the
+		/// current entry's data, not the entire archive, and will
+		/// stop at the end of the current entry's data if the number
+		/// to skip extends beyond that point.
+		/// </summary>
+		/// <param name="skipCount">
+		/// The number of bytes to skip.
+		/// </param>
+		public void Skip(long skipCount)
+		{
+			// TODO: REVIEW efficiency of TarInputStream.Skip
+			// This is horribly inefficient, but it ensures that we
+			// properly skip over bytes via the TarBuffer...
+			//
+			byte[] skipBuf = new byte[8 * 1024];
+
+			for (long num = skipCount; num > 0;)
+			{
+				int toRead = num > skipBuf.Length ? skipBuf.Length : (int)num;
+				int numRead = Read(skipBuf, 0, toRead);
+
+				if (numRead == -1)
+				{
+					break;
+				}
+
+				num -= numRead;
+			}
+		}
+
+		/// <summary>
+		/// Return a value of true if marking is supported; false otherwise.
+		/// </summary>
+		/// <remarks>Currently marking is not supported, the return value is always false.</remarks>
+		public bool IsMarkSupported
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// Since we do not support marking just yet, we do nothing.
+		/// </summary>
+		/// <param name ="markLimit">
+		/// The limit to mark.
+		/// </param>
+		public void Mark(int markLimit)
+		{
+		}
+
+		/// <summary>
+		/// Since we do not support marking just yet, we do nothing.
+		/// </summary>
+		public void Reset()
+		{
+		}
+
+		/// <summary>
+		/// Get the next entry in this tar archive. This will skip
+		/// over any remaining data in the current entry, if there
+		/// is one, and place the input stream at the header of the
+		/// next entry, and read the header and instantiate a new
+		/// TarEntry from the header bytes and return that entry.
+		/// If there are no more entries in the archive, null will
+		/// be returned to indicate that the end of the archive has
+		/// been reached.
+		/// </summary>
+		/// <returns>
+		/// The next TarEntry in the archive, or null.
+		/// </returns>
+		public TarEntry GetNextEntry()
+		{
+			if (hasHitEOF)
+			{
+				return null;
+			}
+
+			if (currentEntry != null)
+			{
+				SkipToNextEntry();
+			}
+
+			byte[] headerBuf = tarBuffer.ReadBlock();
+
+			if (headerBuf == null)
+			{
+				hasHitEOF = true;
+			}
+			else if (TarBuffer.IsEndOfArchiveBlock(headerBuf))
+			{
+				hasHitEOF = true;
+
+				// Read the second zero-filled block
+				tarBuffer.ReadBlock();
+			}
+			else
+			{
+				hasHitEOF = false;
+			}
+
+			if (hasHitEOF)
+			{
+				currentEntry = null;
+			}
+			else
+			{
+				try
+				{
+					var header = new TarHeader();
+					header.ParseBuffer(headerBuf);
+					if (!header.IsChecksumValid)
+					{
+						throw new TarException("Header checksum is invalid");
+					}
+					this.entryOffset = 0;
+					this.entrySize = header.Size;
+
+					StringBuilder longName = null;
+
+					if (header.TypeFlag == TarHeader.LF_GNU_LONGNAME)
+					{
+						byte[] nameBuffer = new byte[TarBuffer.BlockSize];
+						long numToRead = this.entrySize;
+
+						longName = new StringBuilder();
+
+						while (numToRead > 0)
+						{
+							int numRead = this.Read(nameBuffer, 0, (numToRead > nameBuffer.Length ? nameBuffer.Length : (int)numToRead));
+
+							if (numRead == -1)
+							{
+								throw new InvalidHeaderException("Failed to read long name entry");
+							}
+
+							longName.Append(TarHeader.ParseName(nameBuffer, 0, numRead).ToString());
+							numToRead -= numRead;
+						}
+
+						SkipToNextEntry();
+						headerBuf = this.tarBuffer.ReadBlock();
+					}
+					else if (header.TypeFlag == TarHeader.LF_GHDR)
+					{  // POSIX global extended header
+					   // Ignore things we dont understand completely for now
+						SkipToNextEntry();
+						headerBuf = this.tarBuffer.ReadBlock();
+					}
+					else if (header.TypeFlag == TarHeader.LF_XHDR)
+					{  // POSIX extended header
+						byte[] nameBuffer = new byte[TarBuffer.BlockSize];
+						long numToRead = this.entrySize;
+
+						var xhr = new TarExtendedHeaderReader();
+
+						while (numToRead > 0)
+						{
+							int numRead = this.Read(nameBuffer, 0, (numToRead > nameBuffer.Length ? nameBuffer.Length : (int)numToRead));
+
+							if (numRead == -1)
+							{
+								throw new InvalidHeaderException("Failed to read long name entry");
+							}
+
+							xhr.Read(nameBuffer, numRead);
+							numToRead -= numRead;
+						}
+
+						if (xhr.Headers.TryGetValue("path", out string name))
+						{
+							longName = new StringBuilder(name);
+						}
+
+						SkipToNextEntry();
+						headerBuf = this.tarBuffer.ReadBlock();
+					}
+					else if (header.TypeFlag == TarHeader.LF_GNU_VOLHDR)
+					{
+						// TODO: could show volume name when verbose
+						SkipToNextEntry();
+						headerBuf = this.tarBuffer.ReadBlock();
+					}
+					else if (header.TypeFlag != TarHeader.LF_NORMAL &&
+							 header.TypeFlag != TarHeader.LF_OLDNORM &&
+							 header.TypeFlag != TarHeader.LF_LINK &&
+							 header.TypeFlag != TarHeader.LF_SYMLINK &&
+							 header.TypeFlag != TarHeader.LF_DIR)
+					{
+						// Ignore things we dont understand completely for now
+						SkipToNextEntry();
+						headerBuf = tarBuffer.ReadBlock();
+					}
+
+					if (entryFactory == null)
+					{
+						currentEntry = new TarEntry(headerBuf);
+						if (longName != null)
+						{
+							currentEntry.Name = longName.ToString();
+						}
+					}
+					else
+					{
+						currentEntry = entryFactory.CreateEntry(headerBuf);
+					}
+
+					// Magic was checked here for 'ustar' but there are multiple valid possibilities
+					// so this is not done anymore.
+
+					entryOffset = 0;
+
+					// TODO: Review How do we resolve this discrepancy?!
+					entrySize = this.currentEntry.Size;
+				}
+				catch (InvalidHeaderException ex)
+				{
+					entrySize = 0;
+					entryOffset = 0;
+					currentEntry = null;
+					string errorText = string.Format("Bad header in record {0} block {1} {2}",
+						tarBuffer.CurrentRecord, tarBuffer.CurrentBlock, ex.Message);
+					throw new InvalidHeaderException(errorText);
+				}
+			}
+			return currentEntry;
+		}
+
+		/// <summary>
+		/// Copies the contents of the current tar archive entry directly into
+		/// an output stream.
+		/// </summary>
+		/// <param name="outputStream">
+		/// The OutputStream into which to write the entry's data.
+		/// </param>
+		public void CopyEntryContents(Stream outputStream)
+		{
+			byte[] tempBuffer = new byte[32 * 1024];
+
+			while (true)
+			{
+				int numRead = Read(tempBuffer, 0, tempBuffer.Length);
+				if (numRead <= 0)
+				{
+					break;
+				}
+				outputStream.Write(tempBuffer, 0, numRead);
+			}
+		}
+
+		private void SkipToNextEntry()
+		{
+			long numToSkip = entrySize - entryOffset;
+
+			if (numToSkip > 0)
+			{
+				Skip(numToSkip);
+			}
+
+			readBuffer = null;
+		}
+
+		/// <summary>
+		/// This interface is provided, along with the method <see cref="SetEntryFactory"/>, to allow
+		/// the programmer to have their own <see cref="TarEntry"/> subclass instantiated for the
+		/// entries return from <see cref="GetNextEntry"/>.
+		/// </summary>
+		public interface IEntryFactory
+		{
+			/// <summary>
+			/// Create an entry based on name alone
+			/// </summary>
+			/// <param name="name">
+			/// Name of the new EntryPointNotFoundException to create
+			/// </param>
+			/// <returns>created TarEntry or descendant class</returns>
+			TarEntry CreateEntry(string name);
+
+			/// <summary>
+			/// Create an instance based on an actual file
+			/// </summary>
+			/// <param name="fileName">
+			/// Name of file to represent in the entry
+			/// </param>
+			/// <returns>
+			/// Created TarEntry or descendant class
+			/// </returns>
+			TarEntry CreateEntryFromFile(string fileName);
+
+			/// <summary>
+			/// Create a tar entry based on the header information passed
+			/// </summary>
+			/// <param name="headerBuffer">
+			/// Buffer containing header information to create an an entry from.
+			/// </param>
+			/// <returns>
+			/// Created TarEntry or descendant class
+			/// </returns>
+			TarEntry CreateEntry(byte[] headerBuffer);
+		}
+
+		/// <summary>
+		/// Standard entry factory class creating instances of the class TarEntry
+		/// </summary>
+		public class EntryFactoryAdapter : IEntryFactory
+		{
+			/// <summary>
+			/// Create a <see cref="TarEntry"/> based on named
+			/// </summary>
+			/// <param name="name">The name to use for the entry</param>
+			/// <returns>A new <see cref="TarEntry"/></returns>
+			public TarEntry CreateEntry(string name)
+			{
+				return TarEntry.CreateTarEntry(name);
+			}
+
+			/// <summary>
+			/// Create a tar entry with details obtained from <paramref name="fileName">file</paramref>
+			/// </summary>
+			/// <param name="fileName">The name of the file to retrieve details from.</param>
+			/// <returns>A new <see cref="TarEntry"/></returns>
+			public TarEntry CreateEntryFromFile(string fileName)
+			{
+				return TarEntry.CreateEntryFromFile(fileName);
+			}
+
+			/// <summary>
+			/// Create an entry based on details in <paramref name="headerBuffer">header</paramref>
+			/// </summary>
+			/// <param name="headerBuffer">The buffer containing entry details.</param>
+			/// <returns>A new <see cref="TarEntry"/></returns>
+			public TarEntry CreateEntry(byte[] headerBuffer)
+			{
+				return new TarEntry(headerBuffer);
+			}
+		}
+
+		#region Instance Fields
+
+		/// <summary>
+		/// Flag set when last block has been read
+		/// </summary>
+		protected bool hasHitEOF;
+
+		/// <summary>
+		/// Size of this entry as recorded in header
+		/// </summary>
+		protected long entrySize;
+
+		/// <summary>
+		/// Number of bytes read for this entry so far
+		/// </summary>
+		protected long entryOffset;
+
+		/// <summary>
+		/// Buffer used with calls to <code>Read()</code>
+		/// </summary>
+		protected byte[] readBuffer;
+
+		/// <summary>
+		/// Working buffer
+		/// </summary>
+		protected TarBuffer tarBuffer;
+
+		/// <summary>
+		/// Current entry being read
+		/// </summary>
+		private TarEntry currentEntry;
+
+		/// <summary>
+		/// Factory used to create TarEntry or descendant class instance
+		/// </summary>
+		protected IEntryFactory entryFactory;
+
+		/// <summary>
+		/// Stream used as the source of input data.
+		/// </summary>
+		private readonly Stream inputStream;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Tar/TarOutputStream.cs

@@ -0,0 +1,480 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Tar
+{
+	/// <summary>
+	/// The TarOutputStream writes a UNIX tar archive as an OutputStream.
+	/// Methods are provided to put entries, and then write their contents
+	/// by writing to this stream using write().
+	/// </summary>
+	/// public
+	public class TarOutputStream : Stream
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Construct TarOutputStream using default block factor
+		/// </summary>
+		/// <param name="outputStream">stream to write to</param>
+		public TarOutputStream(Stream outputStream)
+			: this(outputStream, TarBuffer.DefaultBlockFactor)
+		{
+		}
+
+		/// <summary>
+		/// Construct TarOutputStream with user specified block factor
+		/// </summary>
+		/// <param name="outputStream">stream to write to</param>
+		/// <param name="blockFactor">blocking factor</param>
+		public TarOutputStream(Stream outputStream, int blockFactor)
+		{
+			if (outputStream == null)
+			{
+				throw new ArgumentNullException(nameof(outputStream));
+			}
+
+			this.outputStream = outputStream;
+			buffer = TarBuffer.CreateOutputTarBuffer(outputStream, blockFactor);
+
+			assemblyBuffer = new byte[TarBuffer.BlockSize];
+			blockBuffer = new byte[TarBuffer.BlockSize];
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Gets or sets a flag indicating ownership of underlying stream.
+		/// When the flag is true <see cref="Stream.Dispose()" /> will close the underlying stream also.
+		/// </summary>
+		/// <remarks>The default value is true.</remarks>
+		public bool IsStreamOwner
+		{
+			get { return buffer.IsStreamOwner; }
+			set { buffer.IsStreamOwner = value; }
+		}
+
+		/// <summary>
+		/// true if the stream supports reading; otherwise, false.
+		/// </summary>
+		public override bool CanRead
+		{
+			get
+			{
+				return outputStream.CanRead;
+			}
+		}
+
+		/// <summary>
+		/// true if the stream supports seeking; otherwise, false.
+		/// </summary>
+		public override bool CanSeek
+		{
+			get
+			{
+				return outputStream.CanSeek;
+			}
+		}
+
+		/// <summary>
+		/// true if stream supports writing; otherwise, false.
+		/// </summary>
+		public override bool CanWrite
+		{
+			get
+			{
+				return outputStream.CanWrite;
+			}
+		}
+
+		/// <summary>
+		/// length of stream in bytes
+		/// </summary>
+		public override long Length
+		{
+			get
+			{
+				return outputStream.Length;
+			}
+		}
+
+		/// <summary>
+		/// gets or sets the position within the current stream.
+		/// </summary>
+		public override long Position
+		{
+			get
+			{
+				return outputStream.Position;
+			}
+			set
+			{
+				outputStream.Position = value;
+			}
+		}
+
+		/// <summary>
+		/// set the position within the current stream
+		/// </summary>
+		/// <param name="offset">The offset relative to the <paramref name="origin"/> to seek to</param>
+		/// <param name="origin">The <see cref="SeekOrigin"/> to seek from.</param>
+		/// <returns>The new position in the stream.</returns>
+		public override long Seek(long offset, SeekOrigin origin)
+		{
+			return outputStream.Seek(offset, origin);
+		}
+
+		/// <summary>
+		/// Set the length of the current stream
+		/// </summary>
+		/// <param name="value">The new stream length.</param>
+		public override void SetLength(long value)
+		{
+			outputStream.SetLength(value);
+		}
+
+		/// <summary>
+		/// Read a byte from the stream and advance the position within the stream
+		/// by one byte or returns -1 if at the end of the stream.
+		/// </summary>
+		/// <returns>The byte value or -1 if at end of stream</returns>
+		public override int ReadByte()
+		{
+			return outputStream.ReadByte();
+		}
+
+		/// <summary>
+		/// read bytes from the current stream and advance the position within the
+		/// stream by the number of bytes read.
+		/// </summary>
+		/// <param name="buffer">The buffer to store read bytes in.</param>
+		/// <param name="offset">The index into the buffer to being storing bytes at.</param>
+		/// <param name="count">The desired number of bytes to read.</param>
+		/// <returns>The total number of bytes read, or zero if at the end of the stream.
+		/// The number of bytes may be less than the <paramref name="count">count</paramref>
+		/// requested if data is not avialable.</returns>
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			return outputStream.Read(buffer, offset, count);
+		}
+
+		/// <summary>
+		/// All buffered data is written to destination
+		/// </summary>
+		public override void Flush()
+		{
+			outputStream.Flush();
+		}
+
+		/// <summary>
+		/// Ends the TAR archive without closing the underlying OutputStream.
+		/// The result is that the EOF block of nulls is written.
+		/// </summary>
+		public void Finish()
+		{
+			if (IsEntryOpen)
+			{
+				CloseEntry();
+			}
+			WriteEofBlock();
+		}
+
+		/// <summary>
+		/// Ends the TAR archive and closes the underlying OutputStream.
+		/// </summary>
+		/// <remarks>This means that Finish() is called followed by calling the
+		/// TarBuffer's Close().</remarks>
+		protected override void Dispose(bool disposing)
+		{
+			if (!isClosed)
+			{
+				isClosed = true;
+				Finish();
+				buffer.Close();
+			}
+		}
+
+		/// <summary>
+		/// Get the record size being used by this stream's TarBuffer.
+		/// </summary>
+		public int RecordSize
+		{
+			get { return buffer.RecordSize; }
+		}
+
+		/// <summary>
+		/// Get the record size being used by this stream's TarBuffer.
+		/// </summary>
+		/// <returns>
+		/// The TarBuffer record size.
+		/// </returns>
+		[Obsolete("Use RecordSize property instead")]
+		public int GetRecordSize()
+		{
+			return buffer.RecordSize;
+		}
+
+		/// <summary>
+		/// Get a value indicating wether an entry is open, requiring more data to be written.
+		/// </summary>
+		private bool IsEntryOpen
+		{
+			get { return (currBytes < currSize); }
+		}
+
+		/// <summary>
+		/// Put an entry on the output stream. This writes the entry's
+		/// header and positions the output stream for writing
+		/// the contents of the entry. Once this method is called, the
+		/// stream is ready for calls to write() to write the entry's
+		/// contents. Once the contents are written, closeEntry()
+		/// <B>MUST</B> be called to ensure that all buffered data
+		/// is completely written to the output stream.
+		/// </summary>
+		/// <param name="entry">
+		/// The TarEntry to be written to the archive.
+		/// </param>
+		public void PutNextEntry(TarEntry entry)
+		{
+			if (entry == null)
+			{
+				throw new ArgumentNullException(nameof(entry));
+			}
+
+			if (entry.TarHeader.Name.Length > TarHeader.NAMELEN)
+			{
+				var longHeader = new TarHeader();
+				longHeader.TypeFlag = TarHeader.LF_GNU_LONGNAME;
+				longHeader.Name = longHeader.Name + "././@LongLink";
+				longHeader.Mode = 420;//644 by default
+				longHeader.UserId = entry.UserId;
+				longHeader.GroupId = entry.GroupId;
+				longHeader.GroupName = entry.GroupName;
+				longHeader.UserName = entry.UserName;
+				longHeader.LinkName = "";
+				longHeader.Size = entry.TarHeader.Name.Length + 1;  // Plus one to avoid dropping last char
+
+				longHeader.WriteHeader(blockBuffer);
+				buffer.WriteBlock(blockBuffer);  // Add special long filename header block
+
+				int nameCharIndex = 0;
+
+				while (nameCharIndex < entry.TarHeader.Name.Length + 1 /* we've allocated one for the null char, now we must make sure it gets written out */)
+				{
+					Array.Clear(blockBuffer, 0, blockBuffer.Length);
+					TarHeader.GetAsciiBytes(entry.TarHeader.Name, nameCharIndex, this.blockBuffer, 0, TarBuffer.BlockSize); // This func handles OK the extra char out of string length
+					nameCharIndex += TarBuffer.BlockSize;
+					buffer.WriteBlock(blockBuffer);
+				}
+			}
+
+			entry.WriteEntryHeader(blockBuffer);
+			buffer.WriteBlock(blockBuffer);
+
+			currBytes = 0;
+
+			currSize = entry.IsDirectory ? 0 : entry.Size;
+		}
+
+		/// <summary>
+		/// Close an entry. This method MUST be called for all file
+		/// entries that contain data. The reason is that we must
+		/// buffer data written to the stream in order to satisfy
+		/// the buffer's block based writes. Thus, there may be
+		/// data fragments still being assembled that must be written
+		/// to the output stream before this entry is closed and the
+		/// next entry written.
+		/// </summary>
+		public void CloseEntry()
+		{
+			if (assemblyBufferLength > 0)
+			{
+				Array.Clear(assemblyBuffer, assemblyBufferLength, assemblyBuffer.Length - assemblyBufferLength);
+
+				buffer.WriteBlock(assemblyBuffer);
+
+				currBytes += assemblyBufferLength;
+				assemblyBufferLength = 0;
+			}
+
+			if (currBytes < currSize)
+			{
+				string errorText = string.Format(
+					"Entry closed at '{0}' before the '{1}' bytes specified in the header were written",
+					currBytes, currSize);
+				throw new TarException(errorText);
+			}
+		}
+
+		/// <summary>
+		/// Writes a byte to the current tar archive entry.
+		/// This method simply calls Write(byte[], int, int).
+		/// </summary>
+		/// <param name="value">
+		/// The byte to be written.
+		/// </param>
+		public override void WriteByte(byte value)
+		{
+			Write(new byte[] { value }, 0, 1);
+		}
+
+		/// <summary>
+		/// Writes bytes to the current tar archive entry. This method
+		/// is aware of the current entry and will throw an exception if
+		/// you attempt to write bytes past the length specified for the
+		/// current entry. The method is also (painfully) aware of the
+		/// record buffering required by TarBuffer, and manages buffers
+		/// that are not a multiple of recordsize in length, including
+		/// assembling records from small buffers.
+		/// </summary>
+		/// <param name = "buffer">
+		/// The buffer to write to the archive.
+		/// </param>
+		/// <param name = "offset">
+		/// The offset in the buffer from which to get bytes.
+		/// </param>
+		/// <param name = "count">
+		/// The number of bytes to write.
+		/// </param>
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			if (offset < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset), "Cannot be negative");
+			}
+
+			if (buffer.Length - offset < count)
+			{
+				throw new ArgumentException("offset and count combination is invalid");
+			}
+
+			if (count < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(count), "Cannot be negative");
+			}
+
+			if ((currBytes + count) > currSize)
+			{
+				string errorText = string.Format("request to write '{0}' bytes exceeds size in header of '{1}' bytes",
+					count, this.currSize);
+				throw new ArgumentOutOfRangeException(nameof(count), errorText);
+			}
+
+			//
+			// We have to deal with assembly!!!
+			// The programmer can be writing little 32 byte chunks for all
+			// we know, and we must assemble complete blocks for writing.
+			// TODO  REVIEW Maybe this should be in TarBuffer? Could that help to
+			//        eliminate some of the buffer copying.
+			//
+			if (assemblyBufferLength > 0)
+			{
+				if ((assemblyBufferLength + count) >= blockBuffer.Length)
+				{
+					int aLen = blockBuffer.Length - assemblyBufferLength;
+
+					Array.Copy(assemblyBuffer, 0, blockBuffer, 0, assemblyBufferLength);
+					Array.Copy(buffer, offset, blockBuffer, assemblyBufferLength, aLen);
+
+					this.buffer.WriteBlock(blockBuffer);
+
+					currBytes += blockBuffer.Length;
+
+					offset += aLen;
+					count -= aLen;
+
+					assemblyBufferLength = 0;
+				}
+				else
+				{
+					Array.Copy(buffer, offset, assemblyBuffer, assemblyBufferLength, count);
+					offset += count;
+					assemblyBufferLength += count;
+					count -= count;
+				}
+			}
+
+			//
+			// When we get here we have EITHER:
+			//   o An empty "assembly" buffer.
+			//   o No bytes to write (count == 0)
+			//
+			while (count > 0)
+			{
+				if (count < blockBuffer.Length)
+				{
+					Array.Copy(buffer, offset, assemblyBuffer, assemblyBufferLength, count);
+					assemblyBufferLength += count;
+					break;
+				}
+
+				this.buffer.WriteBlock(buffer, offset);
+
+				int bufferLength = blockBuffer.Length;
+				currBytes += bufferLength;
+				count -= bufferLength;
+				offset += bufferLength;
+			}
+		}
+
+		/// <summary>
+		/// Write an EOF (end of archive) block to the tar archive.
+		/// The	end of the archive is indicated	by two blocks consisting entirely of zero bytes.
+		/// </summary>
+		private void WriteEofBlock()
+		{
+			Array.Clear(blockBuffer, 0, blockBuffer.Length);
+			buffer.WriteBlock(blockBuffer);
+			buffer.WriteBlock(blockBuffer);
+		}
+
+		#region Instance Fields
+
+		/// <summary>
+		/// bytes written for this entry so far
+		/// </summary>
+		private long currBytes;
+
+		/// <summary>
+		/// current 'Assembly' buffer length
+		/// </summary>
+		private int assemblyBufferLength;
+
+		/// <summary>
+		/// Flag indicating wether this instance has been closed or not.
+		/// </summary>
+		private bool isClosed;
+
+		/// <summary>
+		/// Size for the current entry
+		/// </summary>
+		protected long currSize;
+
+		/// <summary>
+		/// single block working buffer
+		/// </summary>
+		protected byte[] blockBuffer;
+
+		/// <summary>
+		/// 'Assembly' buffer used to assemble data before writing
+		/// </summary>
+		protected byte[] assemblyBuffer;
+
+		/// <summary>
+		/// TarBuffer used to provide correct blocking factor
+		/// </summary>
+		protected TarBuffer buffer;
+
+		/// <summary>
+		/// the destination stream for the archive contents
+		/// </summary>
+		protected Stream outputStream;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/Deflater.cs

@@ -0,0 +1,604 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	/// <summary>
+	/// This is the Deflater class.  The deflater class compresses input
+	/// with the deflate algorithm described in RFC 1951.  It has several
+	/// compression levels and three different strategies described below.
+	///
+	/// This class is <i>not</i> thread safe.  This is inherent in the API, due
+	/// to the split of deflate and setInput.
+	///
+	/// author of the original java version : Jochen Hoenicke
+	/// </summary>
+	public class Deflater
+	{
+		#region Deflater Documentation
+
+		/*
+		* The Deflater can do the following state transitions:
+		*
+		* (1) -> INIT_STATE   ----> INIT_FINISHING_STATE ---.
+		*        /  | (2)      (5)                          |
+		*       /   v          (5)                          |
+		*   (3)| SETDICT_STATE ---> SETDICT_FINISHING_STATE |(3)
+		*       \   | (3)                 |        ,--------'
+		*        |  |                     | (3)   /
+		*        v  v          (5)        v      v
+		* (1) -> BUSY_STATE   ----> FINISHING_STATE
+		*                                | (6)
+		*                                v
+		*                           FINISHED_STATE
+		*    \_____________________________________/
+		*                    | (7)
+		*                    v
+		*               CLOSED_STATE
+		*
+		* (1) If we should produce a header we start in INIT_STATE, otherwise
+		*     we start in BUSY_STATE.
+		* (2) A dictionary may be set only when we are in INIT_STATE, then
+		*     we change the state as indicated.
+		* (3) Whether a dictionary is set or not, on the first call of deflate
+		*     we change to BUSY_STATE.
+		* (4) -- intentionally left blank -- :)
+		* (5) FINISHING_STATE is entered, when flush() is called to indicate that
+		*     there is no more INPUT.  There are also states indicating, that
+		*     the header wasn't written yet.
+		* (6) FINISHED_STATE is entered, when everything has been flushed to the
+		*     internal pending output buffer.
+		* (7) At any time (7)
+		*
+		*/
+
+		#endregion Deflater Documentation
+
+		#region Public Constants
+
+		/// <summary>
+		/// The best and slowest compression level.  This tries to find very
+		/// long and distant string repetitions.
+		/// </summary>
+		public const int BEST_COMPRESSION = 9;
+
+		/// <summary>
+		/// The worst but fastest compression level.
+		/// </summary>
+		public const int BEST_SPEED = 1;
+
+		/// <summary>
+		/// The default compression level.
+		/// </summary>
+		public const int DEFAULT_COMPRESSION = -1;
+
+		/// <summary>
+		/// This level won't compress at all but output uncompressed blocks.
+		/// </summary>
+		public const int NO_COMPRESSION = 0;
+
+		/// <summary>
+		/// The compression method.  This is the only method supported so far.
+		/// There is no need to use this constant at all.
+		/// </summary>
+		public const int DEFLATED = 8;
+
+		#endregion Public Constants
+
+		#region Public Enum
+
+		/// <summary>
+		/// Compression Level as an enum for safer use
+		/// </summary>
+		public enum CompressionLevel
+		{
+			/// <summary>
+			/// The best and slowest compression level.  This tries to find very
+			/// long and distant string repetitions.
+			/// </summary>
+			BEST_COMPRESSION = Deflater.BEST_COMPRESSION,
+
+			/// <summary>
+			/// The worst but fastest compression level.
+			/// </summary>
+			BEST_SPEED = Deflater.BEST_SPEED,
+
+			/// <summary>
+			/// The default compression level.
+			/// </summary>
+			DEFAULT_COMPRESSION = Deflater.DEFAULT_COMPRESSION,
+
+			/// <summary>
+			/// This level won't compress at all but output uncompressed blocks.
+			/// </summary>
+			NO_COMPRESSION = Deflater.NO_COMPRESSION,
+
+			/// <summary>
+			/// The compression method.  This is the only method supported so far.
+			/// There is no need to use this constant at all.
+			/// </summary>
+			DEFLATED = Deflater.DEFLATED
+		}
+
+		#endregion Public Enum
+
+		#region Local Constants
+
+		private const int IS_SETDICT = 0x01;
+		private const int IS_FLUSHING = 0x04;
+		private const int IS_FINISHING = 0x08;
+
+		private const int INIT_STATE = 0x00;
+		private const int SETDICT_STATE = 0x01;
+
+		//		private static  int INIT_FINISHING_STATE    = 0x08;
+		//		private static  int SETDICT_FINISHING_STATE = 0x09;
+		private const int BUSY_STATE = 0x10;
+
+		private const int FLUSHING_STATE = 0x14;
+		private const int FINISHING_STATE = 0x1c;
+		private const int FINISHED_STATE = 0x1e;
+		private const int CLOSED_STATE = 0x7f;
+
+		#endregion Local Constants
+
+		#region Constructors
+
+		/// <summary>
+		/// Creates a new deflater with default compression level.
+		/// </summary>
+		public Deflater() : this(DEFAULT_COMPRESSION, false)
+		{
+		}
+
+		/// <summary>
+		/// Creates a new deflater with given compression level.
+		/// </summary>
+		/// <param name="level">
+		/// the compression level, a value between NO_COMPRESSION
+		/// and BEST_COMPRESSION, or DEFAULT_COMPRESSION.
+		/// </param>
+		/// <exception cref="System.ArgumentOutOfRangeException">if lvl is out of range.</exception>
+		public Deflater(int level) : this(level, false)
+		{
+		}
+
+		/// <summary>
+		/// Creates a new deflater with given compression level.
+		/// </summary>
+		/// <param name="level">
+		/// the compression level, a value between NO_COMPRESSION
+		/// and BEST_COMPRESSION.
+		/// </param>
+		/// <param name="noZlibHeaderOrFooter">
+		/// true, if we should suppress the Zlib/RFC1950 header at the
+		/// beginning and the adler checksum at the end of the output.  This is
+		/// useful for the GZIP/PKZIP formats.
+		/// </param>
+		/// <exception cref="System.ArgumentOutOfRangeException">if lvl is out of range.</exception>
+		public Deflater(int level, bool noZlibHeaderOrFooter)
+		{
+			if (level == DEFAULT_COMPRESSION)
+			{
+				level = 6;
+			}
+			else if (level < NO_COMPRESSION || level > BEST_COMPRESSION)
+			{
+				throw new ArgumentOutOfRangeException(nameof(level));
+			}
+
+			pending = new DeflaterPending();
+			engine = new DeflaterEngine(pending, noZlibHeaderOrFooter);
+			this.noZlibHeaderOrFooter = noZlibHeaderOrFooter;
+			SetStrategy(DeflateStrategy.Default);
+			SetLevel(level);
+			Reset();
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Resets the deflater.  The deflater acts afterwards as if it was
+		/// just created with the same compression level and strategy as it
+		/// had before.
+		/// </summary>
+		public void Reset()
+		{
+			state = (noZlibHeaderOrFooter ? BUSY_STATE : INIT_STATE);
+			totalOut = 0;
+			pending.Reset();
+			engine.Reset();
+		}
+
+		/// <summary>
+		/// Gets the current adler checksum of the data that was processed so far.
+		/// </summary>
+		public int Adler
+		{
+			get
+			{
+				return engine.Adler;
+			}
+		}
+
+		/// <summary>
+		/// Gets the number of input bytes processed so far.
+		/// </summary>
+		public long TotalIn
+		{
+			get
+			{
+				return engine.TotalIn;
+			}
+		}
+
+		/// <summary>
+		/// Gets the number of output bytes so far.
+		/// </summary>
+		public long TotalOut
+		{
+			get
+			{
+				return totalOut;
+			}
+		}
+
+		/// <summary>
+		/// Flushes the current input block.  Further calls to deflate() will
+		/// produce enough output to inflate everything in the current input
+		/// block.  This is not part of Sun's JDK so I have made it package
+		/// private.  It is used by DeflaterOutputStream to implement
+		/// flush().
+		/// </summary>
+		public void Flush()
+		{
+			state |= IS_FLUSHING;
+		}
+
+		/// <summary>
+		/// Finishes the deflater with the current input block.  It is an error
+		/// to give more input after this method was called.  This method must
+		/// be called to force all bytes to be flushed.
+		/// </summary>
+		public void Finish()
+		{
+			state |= (IS_FLUSHING | IS_FINISHING);
+		}
+
+		/// <summary>
+		/// Returns true if the stream was finished and no more output bytes
+		/// are available.
+		/// </summary>
+		public bool IsFinished
+		{
+			get
+			{
+				return (state == FINISHED_STATE) && pending.IsFlushed;
+			}
+		}
+
+		/// <summary>
+		/// Returns true, if the input buffer is empty.
+		/// You should then call setInput().
+		/// NOTE: This method can also return true when the stream
+		/// was finished.
+		/// </summary>
+		public bool IsNeedingInput
+		{
+			get
+			{
+				return engine.NeedsInput();
+			}
+		}
+
+		/// <summary>
+		/// Sets the data which should be compressed next.  This should be only
+		/// called when needsInput indicates that more input is needed.
+		/// If you call setInput when needsInput() returns false, the
+		/// previous input that is still pending will be thrown away.
+		/// The given byte array should not be changed, before needsInput() returns
+		/// true again.
+		/// This call is equivalent to <code>setInput(input, 0, input.length)</code>.
+		/// </summary>
+		/// <param name="input">
+		/// the buffer containing the input data.
+		/// </param>
+		/// <exception cref="System.InvalidOperationException">
+		/// if the buffer was finished() or ended().
+		/// </exception>
+		public void SetInput(byte[] input)
+		{
+			SetInput(input, 0, input.Length);
+		}
+
+		/// <summary>
+		/// Sets the data which should be compressed next.  This should be
+		/// only called when needsInput indicates that more input is needed.
+		/// The given byte array should not be changed, before needsInput() returns
+		/// true again.
+		/// </summary>
+		/// <param name="input">
+		/// the buffer containing the input data.
+		/// </param>
+		/// <param name="offset">
+		/// the start of the data.
+		/// </param>
+		/// <param name="count">
+		/// the number of data bytes of input.
+		/// </param>
+		/// <exception cref="System.InvalidOperationException">
+		/// if the buffer was Finish()ed or if previous input is still pending.
+		/// </exception>
+		public void SetInput(byte[] input, int offset, int count)
+		{
+			if ((state & IS_FINISHING) != 0)
+			{
+				throw new InvalidOperationException("Finish() already called");
+			}
+			engine.SetInput(input, offset, count);
+		}
+
+		/// <summary>
+		/// Sets the compression level.  There is no guarantee of the exact
+		/// position of the change, but if you call this when needsInput is
+		/// true the change of compression level will occur somewhere near
+		/// before the end of the so far given input.
+		/// </summary>
+		/// <param name="level">
+		/// the new compression level.
+		/// </param>
+		public void SetLevel(int level)
+		{
+			if (level == DEFAULT_COMPRESSION)
+			{
+				level = 6;
+			}
+			else if (level < NO_COMPRESSION || level > BEST_COMPRESSION)
+			{
+				throw new ArgumentOutOfRangeException(nameof(level));
+			}
+
+			if (this.level != level)
+			{
+				this.level = level;
+				engine.SetLevel(level);
+			}
+		}
+
+		/// <summary>
+		/// Get current compression level
+		/// </summary>
+		/// <returns>Returns the current compression level</returns>
+		public int GetLevel()
+		{
+			return level;
+		}
+
+		/// <summary>
+		/// Sets the compression strategy. Strategy is one of
+		/// DEFAULT_STRATEGY, HUFFMAN_ONLY and FILTERED.  For the exact
+		/// position where the strategy is changed, the same as for
+		/// SetLevel() applies.
+		/// </summary>
+		/// <param name="strategy">
+		/// The new compression strategy.
+		/// </param>
+		public void SetStrategy(DeflateStrategy strategy)
+		{
+			engine.Strategy = strategy;
+		}
+
+		/// <summary>
+		/// Deflates the current input block with to the given array.
+		/// </summary>
+		/// <param name="output">
+		/// The buffer where compressed data is stored
+		/// </param>
+		/// <returns>
+		/// The number of compressed bytes added to the output, or 0 if either
+		/// IsNeedingInput() or IsFinished returns true or length is zero.
+		/// </returns>
+		public int Deflate(byte[] output)
+		{
+			return Deflate(output, 0, output.Length);
+		}
+
+		/// <summary>
+		/// Deflates the current input block to the given array.
+		/// </summary>
+		/// <param name="output">
+		/// Buffer to store the compressed data.
+		/// </param>
+		/// <param name="offset">
+		/// Offset into the output array.
+		/// </param>
+		/// <param name="length">
+		/// The maximum number of bytes that may be stored.
+		/// </param>
+		/// <returns>
+		/// The number of compressed bytes added to the output, or 0 if either
+		/// needsInput() or finished() returns true or length is zero.
+		/// </returns>
+		/// <exception cref="System.InvalidOperationException">
+		/// If Finish() was previously called.
+		/// </exception>
+		/// <exception cref="System.ArgumentOutOfRangeException">
+		/// If offset or length don't match the array length.
+		/// </exception>
+		public int Deflate(byte[] output, int offset, int length)
+		{
+			int origLength = length;
+
+			if (state == CLOSED_STATE)
+			{
+				throw new InvalidOperationException("Deflater closed");
+			}
+
+			if (state < BUSY_STATE)
+			{
+				// output header
+				int header = (DEFLATED +
+					((DeflaterConstants.MAX_WBITS - 8) << 4)) << 8;
+				int level_flags = (level - 1) >> 1;
+				if (level_flags < 0 || level_flags > 3)
+				{
+					level_flags = 3;
+				}
+				header |= level_flags << 6;
+				if ((state & IS_SETDICT) != 0)
+				{
+					// Dictionary was set
+					header |= DeflaterConstants.PRESET_DICT;
+				}
+				header += 31 - (header % 31);
+
+				pending.WriteShortMSB(header);
+				if ((state & IS_SETDICT) != 0)
+				{
+					int chksum = engine.Adler;
+					engine.ResetAdler();
+					pending.WriteShortMSB(chksum >> 16);
+					pending.WriteShortMSB(chksum & 0xffff);
+				}
+
+				state = BUSY_STATE | (state & (IS_FLUSHING | IS_FINISHING));
+			}
+
+			for (; ; )
+			{
+				int count = pending.Flush(output, offset, length);
+				offset += count;
+				totalOut += count;
+				length -= count;
+
+				if (length == 0 || state == FINISHED_STATE)
+				{
+					break;
+				}
+
+				if (!engine.Deflate((state & IS_FLUSHING) != 0, (state & IS_FINISHING) != 0))
+				{
+					switch (state)
+					{
+						case BUSY_STATE:
+							// We need more input now
+							return origLength - length;
+
+						case FLUSHING_STATE:
+							if (level != NO_COMPRESSION)
+							{
+								/* We have to supply some lookahead.  8 bit lookahead
+								 * is needed by the zlib inflater, and we must fill
+								 * the next byte, so that all bits are flushed.
+								 */
+								int neededbits = 8 + ((-pending.BitCount) & 7);
+								while (neededbits > 0)
+								{
+									/* write a static tree block consisting solely of
+									 * an EOF:
+									 */
+									pending.WriteBits(2, 10);
+									neededbits -= 10;
+								}
+							}
+							state = BUSY_STATE;
+							break;
+
+						case FINISHING_STATE:
+							pending.AlignToByte();
+
+							// Compressed data is complete.  Write footer information if required.
+							if (!noZlibHeaderOrFooter)
+							{
+								int adler = engine.Adler;
+								pending.WriteShortMSB(adler >> 16);
+								pending.WriteShortMSB(adler & 0xffff);
+							}
+							state = FINISHED_STATE;
+							break;
+					}
+				}
+			}
+			return origLength - length;
+		}
+
+		/// <summary>
+		/// Sets the dictionary which should be used in the deflate process.
+		/// This call is equivalent to <code>setDictionary(dict, 0, dict.Length)</code>.
+		/// </summary>
+		/// <param name="dictionary">
+		/// the dictionary.
+		/// </param>
+		/// <exception cref="System.InvalidOperationException">
+		/// if SetInput () or Deflate () were already called or another dictionary was already set.
+		/// </exception>
+		public void SetDictionary(byte[] dictionary)
+		{
+			SetDictionary(dictionary, 0, dictionary.Length);
+		}
+
+		/// <summary>
+		/// Sets the dictionary which should be used in the deflate process.
+		/// The dictionary is a byte array containing strings that are
+		/// likely to occur in the data which should be compressed.  The
+		/// dictionary is not stored in the compressed output, only a
+		/// checksum.  To decompress the output you need to supply the same
+		/// dictionary again.
+		/// </summary>
+		/// <param name="dictionary">
+		/// The dictionary data
+		/// </param>
+		/// <param name="index">
+		/// The index where dictionary information commences.
+		/// </param>
+		/// <param name="count">
+		/// The number of bytes in the dictionary.
+		/// </param>
+		/// <exception cref="System.InvalidOperationException">
+		/// If SetInput () or Deflate() were already called or another dictionary was already set.
+		/// </exception>
+		public void SetDictionary(byte[] dictionary, int index, int count)
+		{
+			if (state != INIT_STATE)
+			{
+				throw new InvalidOperationException();
+			}
+
+			state = SETDICT_STATE;
+			engine.SetDictionary(dictionary, index, count);
+		}
+
+		#region Instance Fields
+
+		/// <summary>
+		/// Compression level.
+		/// </summary>
+		private int level;
+
+		/// <summary>
+		/// If true no Zlib/RFC1950 headers or footers are generated
+		/// </summary>
+		private bool noZlibHeaderOrFooter;
+
+		/// <summary>
+		/// The current state.
+		/// </summary>
+		private int state;
+
+		/// <summary>
+		/// The total bytes of output written.
+		/// </summary>
+		private long totalOut;
+
+		/// <summary>
+		/// The pending output.
+		/// </summary>
+		private DeflaterPending pending;
+
+		/// <summary>
+		/// The deflater engine.
+		/// </summary>
+		private DeflaterEngine engine;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/DeflaterConstants.cs

@@ -0,0 +1,145 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	/// <summary>
+	/// This class contains constants used for deflation.
+	/// </summary>
+	public static class DeflaterConstants
+	{
+		/// <summary>
+		/// Set to true to enable debugging
+		/// </summary>
+		public const bool DEBUGGING = false;
+
+		/// <summary>
+		/// Written to Zip file to identify a stored block
+		/// </summary>
+		public const int STORED_BLOCK = 0;
+
+		/// <summary>
+		/// Identifies static tree in Zip file
+		/// </summary>
+		public const int STATIC_TREES = 1;
+
+		/// <summary>
+		/// Identifies dynamic tree in Zip file
+		/// </summary>
+		public const int DYN_TREES = 2;
+
+		/// <summary>
+		/// Header flag indicating a preset dictionary for deflation
+		/// </summary>
+		public const int PRESET_DICT = 0x20;
+
+		/// <summary>
+		/// Sets internal buffer sizes for Huffman encoding
+		/// </summary>
+		public const int DEFAULT_MEM_LEVEL = 8;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int MAX_MATCH = 258;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int MIN_MATCH = 3;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int MAX_WBITS = 15;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int WSIZE = 1 << MAX_WBITS;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int WMASK = WSIZE - 1;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int HASH_BITS = DEFAULT_MEM_LEVEL + 7;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int HASH_SIZE = 1 << HASH_BITS;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int HASH_MASK = HASH_SIZE - 1;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int HASH_SHIFT = (HASH_BITS + MIN_MATCH - 1) / MIN_MATCH;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int MIN_LOOKAHEAD = MAX_MATCH + MIN_MATCH + 1;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int MAX_DIST = WSIZE - MIN_LOOKAHEAD;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int PENDING_BUF_SIZE = 1 << (DEFAULT_MEM_LEVEL + 8);
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public static int MAX_BLOCK_SIZE = Math.Min(65535, PENDING_BUF_SIZE - 5);
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int DEFLATE_STORED = 0;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int DEFLATE_FAST = 1;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public const int DEFLATE_SLOW = 2;
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public static int[] GOOD_LENGTH = { 0, 4, 4, 4, 4, 8, 8, 8, 32, 32 };
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public static int[] MAX_LAZY = { 0, 4, 5, 6, 4, 16, 16, 32, 128, 258 };
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public static int[] NICE_LENGTH = { 0, 8, 16, 32, 16, 32, 128, 128, 258, 258 };
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public static int[] MAX_CHAIN = { 0, 4, 8, 32, 16, 32, 128, 256, 1024, 4096 };
+
+		/// <summary>
+		/// Internal compression engine constant
+		/// </summary>
+		public static int[] COMPR_FUNC = { 0, 1, 1, 1, 1, 2, 2, 2, 2, 2 };
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/DeflaterEngine.cs

@@ -0,0 +1,946 @@
+using ICSharpCode.SharpZipLib.Checksum;
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	/// <summary>
+	/// Strategies for deflater
+	/// </summary>
+	public enum DeflateStrategy
+	{
+		/// <summary>
+		/// The default strategy
+		/// </summary>
+		Default = 0,
+
+		/// <summary>
+		/// This strategy will only allow longer string repetitions.  It is
+		/// useful for random data with a small character set.
+		/// </summary>
+		Filtered = 1,
+
+		/// <summary>
+		/// This strategy will not look for string repetitions at all.  It
+		/// only encodes with Huffman trees (which means, that more common
+		/// characters get a smaller encoding.
+		/// </summary>
+		HuffmanOnly = 2
+	}
+
+	// DEFLATE ALGORITHM:
+	//
+	// The uncompressed stream is inserted into the window array.  When
+	// the window array is full the first half is thrown away and the
+	// second half is copied to the beginning.
+	//
+	// The head array is a hash table.  Three characters build a hash value
+	// and they the value points to the corresponding index in window of
+	// the last string with this hash.  The prev array implements a
+	// linked list of matches with the same hash: prev[index & WMASK] points
+	// to the previous index with the same hash.
+	//
+
+	/// <summary>
+	/// Low level compression engine for deflate algorithm which uses a 32K sliding window
+	/// with secondary compression from Huffman/Shannon-Fano codes.
+	/// </summary>
+	public class DeflaterEngine
+	{
+		#region Constants
+
+		private const int TooFar = 4096;
+
+		#endregion Constants
+
+		#region Constructors
+
+		/// <summary>
+		/// Construct instance with pending buffer
+		/// Adler calculation will be peformed
+		/// </summary>
+		/// <param name="pending">
+		/// Pending buffer to use
+		/// </param>
+		public DeflaterEngine(DeflaterPending pending)
+			: this (pending, false)
+		{
+		}
+
+
+
+		/// <summary>
+		/// Construct instance with pending buffer
+		/// </summary>
+		/// <param name="pending">
+		/// Pending buffer to use
+		/// </param>
+		/// <param name="noAdlerCalculation">
+		/// If no adler calculation should be performed
+		/// </param>
+		public DeflaterEngine(DeflaterPending pending, bool noAdlerCalculation)
+		{
+			this.pending = pending;
+			huffman = new DeflaterHuffman(pending);
+			if (!noAdlerCalculation)
+				adler = new Adler32();
+
+			window = new byte[2 * DeflaterConstants.WSIZE];
+			head = new short[DeflaterConstants.HASH_SIZE];
+			prev = new short[DeflaterConstants.WSIZE];
+
+			// We start at index 1, to avoid an implementation deficiency, that
+			// we cannot build a repeat pattern at index 0.
+			blockStart = strstart = 1;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Deflate drives actual compression of data
+		/// </summary>
+		/// <param name="flush">True to flush input buffers</param>
+		/// <param name="finish">Finish deflation with the current input.</param>
+		/// <returns>Returns true if progress has been made.</returns>
+		public bool Deflate(bool flush, bool finish)
+		{
+			bool progress;
+			do
+			{
+				FillWindow();
+				bool canFlush = flush && (inputOff == inputEnd);
+
+#if DebugDeflation
+				if (DeflaterConstants.DEBUGGING) {
+					Console.WriteLine("window: [" + blockStart + "," + strstart + ","
+								+ lookahead + "], " + compressionFunction + "," + canFlush);
+				}
+#endif
+				switch (compressionFunction)
+				{
+					case DeflaterConstants.DEFLATE_STORED:
+						progress = DeflateStored(canFlush, finish);
+						break;
+
+					case DeflaterConstants.DEFLATE_FAST:
+						progress = DeflateFast(canFlush, finish);
+						break;
+
+					case DeflaterConstants.DEFLATE_SLOW:
+						progress = DeflateSlow(canFlush, finish);
+						break;
+
+					default:
+						throw new InvalidOperationException("unknown compressionFunction");
+				}
+			} while (pending.IsFlushed && progress); // repeat while we have no pending output and progress was made
+			return progress;
+		}
+
+		/// <summary>
+		/// Sets input data to be deflated.  Should only be called when <code>NeedsInput()</code>
+		/// returns true
+		/// </summary>
+		/// <param name="buffer">The buffer containing input data.</param>
+		/// <param name="offset">The offset of the first byte of data.</param>
+		/// <param name="count">The number of bytes of data to use as input.</param>
+		public void SetInput(byte[] buffer, int offset, int count)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			if (offset < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset));
+			}
+
+			if (count < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(count));
+			}
+
+			if (inputOff < inputEnd)
+			{
+				throw new InvalidOperationException("Old input was not completely processed");
+			}
+
+			int end = offset + count;
+
+			/* We want to throw an ArrayIndexOutOfBoundsException early.  The
+			* check is very tricky: it also handles integer wrap around.
+			*/
+			if ((offset > end) || (end > buffer.Length))
+			{
+				throw new ArgumentOutOfRangeException(nameof(count));
+			}
+
+			inputBuf = buffer;
+			inputOff = offset;
+			inputEnd = end;
+		}
+
+		/// <summary>
+		/// Determines if more <see cref="SetInput">input</see> is needed.
+		/// </summary>
+		/// <returns>Return true if input is needed via <see cref="SetInput">SetInput</see></returns>
+		public bool NeedsInput()
+		{
+			return (inputEnd == inputOff);
+		}
+
+		/// <summary>
+		/// Set compression dictionary
+		/// </summary>
+		/// <param name="buffer">The buffer containing the dictionary data</param>
+		/// <param name="offset">The offset in the buffer for the first byte of data</param>
+		/// <param name="length">The length of the dictionary data.</param>
+		public void SetDictionary(byte[] buffer, int offset, int length)
+		{
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING && (strstart != 1) )
+			{
+				throw new InvalidOperationException("strstart not 1");
+			}
+#endif
+			adler?.Update(new ArraySegment<byte>(buffer, offset, length));
+			if (length < DeflaterConstants.MIN_MATCH)
+			{
+				return;
+			}
+
+			if (length > DeflaterConstants.MAX_DIST)
+			{
+				offset += length - DeflaterConstants.MAX_DIST;
+				length = DeflaterConstants.MAX_DIST;
+			}
+
+			System.Array.Copy(buffer, offset, window, strstart, length);
+
+			UpdateHash();
+			--length;
+			while (--length > 0)
+			{
+				InsertString();
+				strstart++;
+			}
+			strstart += 2;
+			blockStart = strstart;
+		}
+
+		/// <summary>
+		/// Reset internal state
+		/// </summary>
+		public void Reset()
+		{
+			huffman.Reset();
+			adler?.Reset();
+			blockStart = strstart = 1;
+			lookahead = 0;
+			totalIn = 0;
+			prevAvailable = false;
+			matchLen = DeflaterConstants.MIN_MATCH - 1;
+
+			for (int i = 0; i < DeflaterConstants.HASH_SIZE; i++)
+			{
+				head[i] = 0;
+			}
+
+			for (int i = 0; i < DeflaterConstants.WSIZE; i++)
+			{
+				prev[i] = 0;
+			}
+		}
+
+		/// <summary>
+		/// Reset Adler checksum
+		/// </summary>
+		public void ResetAdler()
+		{
+			adler?.Reset();
+		}
+
+		/// <summary>
+		/// Get current value of Adler checksum
+		/// </summary>
+		public int Adler
+		{
+			get
+			{
+				return (adler != null) ? unchecked((int)adler.Value) : 0;
+			}
+		}
+
+		/// <summary>
+		/// Total data processed
+		/// </summary>
+		public long TotalIn
+		{
+			get
+			{
+				return totalIn;
+			}
+		}
+
+		/// <summary>
+		/// Get/set the <see cref="DeflateStrategy">deflate strategy</see>
+		/// </summary>
+		public DeflateStrategy Strategy
+		{
+			get
+			{
+				return strategy;
+			}
+			set
+			{
+				strategy = value;
+			}
+		}
+
+		/// <summary>
+		/// Set the deflate level (0-9)
+		/// </summary>
+		/// <param name="level">The value to set the level to.</param>
+		public void SetLevel(int level)
+		{
+			if ((level < 0) || (level > 9))
+			{
+				throw new ArgumentOutOfRangeException(nameof(level));
+			}
+
+			goodLength = DeflaterConstants.GOOD_LENGTH[level];
+			max_lazy = DeflaterConstants.MAX_LAZY[level];
+			niceLength = DeflaterConstants.NICE_LENGTH[level];
+			max_chain = DeflaterConstants.MAX_CHAIN[level];
+
+			if (DeflaterConstants.COMPR_FUNC[level] != compressionFunction)
+			{
+#if DebugDeflation
+				if (DeflaterConstants.DEBUGGING) {
+				   Console.WriteLine("Change from " + compressionFunction + " to "
+										  + DeflaterConstants.COMPR_FUNC[level]);
+				}
+#endif
+				switch (compressionFunction)
+				{
+					case DeflaterConstants.DEFLATE_STORED:
+						if (strstart > blockStart)
+						{
+							huffman.FlushStoredBlock(window, blockStart,
+								strstart - blockStart, false);
+							blockStart = strstart;
+						}
+						UpdateHash();
+						break;
+
+					case DeflaterConstants.DEFLATE_FAST:
+						if (strstart > blockStart)
+						{
+							huffman.FlushBlock(window, blockStart, strstart - blockStart,
+								false);
+							blockStart = strstart;
+						}
+						break;
+
+					case DeflaterConstants.DEFLATE_SLOW:
+						if (prevAvailable)
+						{
+							huffman.TallyLit(window[strstart - 1] & 0xff);
+						}
+						if (strstart > blockStart)
+						{
+							huffman.FlushBlock(window, blockStart, strstart - blockStart, false);
+							blockStart = strstart;
+						}
+						prevAvailable = false;
+						matchLen = DeflaterConstants.MIN_MATCH - 1;
+						break;
+				}
+				compressionFunction = DeflaterConstants.COMPR_FUNC[level];
+			}
+		}
+
+		/// <summary>
+		/// Fill the window
+		/// </summary>
+		public void FillWindow()
+		{
+			/* If the window is almost full and there is insufficient lookahead,
+			 * move the upper half to the lower one to make room in the upper half.
+			 */
+			if (strstart >= DeflaterConstants.WSIZE + DeflaterConstants.MAX_DIST)
+			{
+				SlideWindow();
+			}
+
+			/* If there is not enough lookahead, but still some input left,
+			 * read in the input
+			 */
+			if (lookahead < DeflaterConstants.MIN_LOOKAHEAD && inputOff < inputEnd)
+			{
+				int more = 2 * DeflaterConstants.WSIZE - lookahead - strstart;
+
+				if (more > inputEnd - inputOff)
+				{
+					more = inputEnd - inputOff;
+				}
+
+				System.Array.Copy(inputBuf, inputOff, window, strstart + lookahead, more);
+				adler?.Update(new ArraySegment<byte>(inputBuf, inputOff, more));
+
+				inputOff += more;
+				totalIn += more;
+				lookahead += more;
+			}
+
+			if (lookahead >= DeflaterConstants.MIN_MATCH)
+			{
+				UpdateHash();
+			}
+		}
+
+		private void UpdateHash()
+		{
+			/*
+						if (DEBUGGING) {
+							Console.WriteLine("updateHash: "+strstart);
+						}
+			*/
+			ins_h = (window[strstart] << DeflaterConstants.HASH_SHIFT) ^ window[strstart + 1];
+		}
+
+		/// <summary>
+		/// Inserts the current string in the head hash and returns the previous
+		/// value for this hash.
+		/// </summary>
+		/// <returns>The previous hash value</returns>
+		private int InsertString()
+		{
+			short match;
+			int hash = ((ins_h << DeflaterConstants.HASH_SHIFT) ^ window[strstart + (DeflaterConstants.MIN_MATCH - 1)]) & DeflaterConstants.HASH_MASK;
+
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING)
+			{
+				if (hash != (((window[strstart] << (2*HASH_SHIFT)) ^
+								  (window[strstart + 1] << HASH_SHIFT) ^
+								  (window[strstart + 2])) & HASH_MASK)) {
+						throw new SharpZipBaseException("hash inconsistent: " + hash + "/"
+												+window[strstart] + ","
+												+window[strstart + 1] + ","
+												+window[strstart + 2] + "," + HASH_SHIFT);
+					}
+			}
+#endif
+			prev[strstart & DeflaterConstants.WMASK] = match = head[hash];
+			head[hash] = unchecked((short)strstart);
+			ins_h = hash;
+			return match & 0xffff;
+		}
+
+		private void SlideWindow()
+		{
+			Array.Copy(window, DeflaterConstants.WSIZE, window, 0, DeflaterConstants.WSIZE);
+			matchStart -= DeflaterConstants.WSIZE;
+			strstart -= DeflaterConstants.WSIZE;
+			blockStart -= DeflaterConstants.WSIZE;
+
+			// Slide the hash table (could be avoided with 32 bit values
+			// at the expense of memory usage).
+			for (int i = 0; i < DeflaterConstants.HASH_SIZE; ++i)
+			{
+				int m = head[i] & 0xffff;
+				head[i] = (short)(m >= DeflaterConstants.WSIZE ? (m - DeflaterConstants.WSIZE) : 0);
+			}
+
+			// Slide the prev table.
+			for (int i = 0; i < DeflaterConstants.WSIZE; i++)
+			{
+				int m = prev[i] & 0xffff;
+				prev[i] = (short)(m >= DeflaterConstants.WSIZE ? (m - DeflaterConstants.WSIZE) : 0);
+			}
+		}
+
+		/// <summary>
+		/// Find the best (longest) string in the window matching the
+		/// string starting at strstart.
+		///
+		/// Preconditions:
+		/// <code>
+		/// strstart + DeflaterConstants.MAX_MATCH &lt;= window.length.</code>
+		/// </summary>
+		/// <param name="curMatch"></param>
+		/// <returns>True if a match greater than the minimum length is found</returns>
+		private bool FindLongestMatch(int curMatch)
+		{
+			int match;
+			int scan = strstart;
+			// scanMax is the highest position that we can look at
+			int scanMax = scan + Math.Min(DeflaterConstants.MAX_MATCH, lookahead) - 1;
+			int limit = Math.Max(scan - DeflaterConstants.MAX_DIST, 0);
+
+			byte[] window = this.window;
+			short[] prev = this.prev;
+			int chainLength = this.max_chain;
+			int niceLength = Math.Min(this.niceLength, lookahead);
+
+			matchLen = Math.Max(matchLen, DeflaterConstants.MIN_MATCH - 1);
+
+			if (scan + matchLen > scanMax) return false;
+
+			byte scan_end1 = window[scan + matchLen - 1];
+			byte scan_end = window[scan + matchLen];
+
+			// Do not waste too much time if we already have a good match:
+			if (matchLen >= this.goodLength) chainLength >>= 2;
+
+			do
+			{
+				match = curMatch;
+				scan = strstart;
+
+				if (window[match + matchLen] != scan_end
+				 || window[match + matchLen - 1] != scan_end1
+				 || window[match] != window[scan]
+				 || window[++match] != window[++scan])
+				{
+					continue;
+				}
+
+				// scan is set to strstart+1 and the comparison passed, so
+				// scanMax - scan is the maximum number of bytes we can compare.
+				// below we compare 8 bytes at a time, so first we compare
+				// (scanMax - scan) % 8 bytes, so the remainder is a multiple of 8
+
+				switch ((scanMax - scan) % 8)
+				{
+					case 1:
+						if (window[++scan] == window[++match]) break;
+						break;
+
+					case 2:
+						if (window[++scan] == window[++match]
+				  && window[++scan] == window[++match]) break;
+						break;
+
+					case 3:
+						if (window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]) break;
+						break;
+
+					case 4:
+						if (window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]) break;
+						break;
+
+					case 5:
+						if (window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]) break;
+						break;
+
+					case 6:
+						if (window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]) break;
+						break;
+
+					case 7:
+						if (window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]
+				  && window[++scan] == window[++match]) break;
+						break;
+				}
+
+				if (window[scan] == window[match])
+				{
+					/* We check for insufficient lookahead only every 8th comparison;
+					 * the 256th check will be made at strstart + 258 unless lookahead is
+					 * exhausted first.
+					 */
+					do
+					{
+						if (scan == scanMax)
+						{
+							++scan;     // advance to first position not matched
+							++match;
+
+							break;
+						}
+					}
+					while (window[++scan] == window[++match]
+						&& window[++scan] == window[++match]
+						&& window[++scan] == window[++match]
+						&& window[++scan] == window[++match]
+						&& window[++scan] == window[++match]
+						&& window[++scan] == window[++match]
+						&& window[++scan] == window[++match]
+						&& window[++scan] == window[++match]);
+				}
+
+				if (scan - strstart > matchLen)
+				{
+#if DebugDeflation
+              if (DeflaterConstants.DEBUGGING && (ins_h == 0) )
+              Console.Error.WriteLine("Found match: " + curMatch + "-" + (scan - strstart));
+#endif
+
+					matchStart = curMatch;
+					matchLen = scan - strstart;
+
+					if (matchLen >= niceLength)
+						break;
+
+					scan_end1 = window[scan - 1];
+					scan_end = window[scan];
+				}
+			} while ((curMatch = (prev[curMatch & DeflaterConstants.WMASK] & 0xffff)) > limit && 0 != --chainLength);
+
+			return matchLen >= DeflaterConstants.MIN_MATCH;
+		}
+
+		private bool DeflateStored(bool flush, bool finish)
+		{
+			if (!flush && (lookahead == 0))
+			{
+				return false;
+			}
+
+			strstart += lookahead;
+			lookahead = 0;
+
+			int storedLength = strstart - blockStart;
+
+			if ((storedLength >= DeflaterConstants.MAX_BLOCK_SIZE) || // Block is full
+				(blockStart < DeflaterConstants.WSIZE && storedLength >= DeflaterConstants.MAX_DIST) ||   // Block may move out of window
+				flush)
+			{
+				bool lastBlock = finish;
+				if (storedLength > DeflaterConstants.MAX_BLOCK_SIZE)
+				{
+					storedLength = DeflaterConstants.MAX_BLOCK_SIZE;
+					lastBlock = false;
+				}
+
+#if DebugDeflation
+				if (DeflaterConstants.DEBUGGING)
+				{
+				   Console.WriteLine("storedBlock[" + storedLength + "," + lastBlock + "]");
+				}
+#endif
+
+				huffman.FlushStoredBlock(window, blockStart, storedLength, lastBlock);
+				blockStart += storedLength;
+				return !lastBlock;
+			}
+			return true;
+		}
+
+		private bool DeflateFast(bool flush, bool finish)
+		{
+			if (lookahead < DeflaterConstants.MIN_LOOKAHEAD && !flush)
+			{
+				return false;
+			}
+
+			while (lookahead >= DeflaterConstants.MIN_LOOKAHEAD || flush)
+			{
+				if (lookahead == 0)
+				{
+					// We are flushing everything
+					huffman.FlushBlock(window, blockStart, strstart - blockStart, finish);
+					blockStart = strstart;
+					return false;
+				}
+
+				if (strstart > 2 * DeflaterConstants.WSIZE - DeflaterConstants.MIN_LOOKAHEAD)
+				{
+					/* slide window, as FindLongestMatch needs this.
+					 * This should only happen when flushing and the window
+					 * is almost full.
+					 */
+					SlideWindow();
+				}
+
+				int hashHead;
+				if (lookahead >= DeflaterConstants.MIN_MATCH &&
+					(hashHead = InsertString()) != 0 &&
+					strategy != DeflateStrategy.HuffmanOnly &&
+					strstart - hashHead <= DeflaterConstants.MAX_DIST &&
+					FindLongestMatch(hashHead))
+				{
+					// longestMatch sets matchStart and matchLen
+#if DebugDeflation
+					if (DeflaterConstants.DEBUGGING)
+					{
+						for (int i = 0 ; i < matchLen; i++) {
+							if (window[strstart + i] != window[matchStart + i]) {
+								throw new SharpZipBaseException("Match failure");
+							}
+						}
+					}
+#endif
+
+					bool full = huffman.TallyDist(strstart - matchStart, matchLen);
+
+					lookahead -= matchLen;
+					if (matchLen <= max_lazy && lookahead >= DeflaterConstants.MIN_MATCH)
+					{
+						while (--matchLen > 0)
+						{
+							++strstart;
+							InsertString();
+						}
+						++strstart;
+					}
+					else
+					{
+						strstart += matchLen;
+						if (lookahead >= DeflaterConstants.MIN_MATCH - 1)
+						{
+							UpdateHash();
+						}
+					}
+					matchLen = DeflaterConstants.MIN_MATCH - 1;
+					if (!full)
+					{
+						continue;
+					}
+				}
+				else
+				{
+					// No match found
+					huffman.TallyLit(window[strstart] & 0xff);
+					++strstart;
+					--lookahead;
+				}
+
+				if (huffman.IsFull())
+				{
+					bool lastBlock = finish && (lookahead == 0);
+					huffman.FlushBlock(window, blockStart, strstart - blockStart, lastBlock);
+					blockStart = strstart;
+					return !lastBlock;
+				}
+			}
+			return true;
+		}
+
+		private bool DeflateSlow(bool flush, bool finish)
+		{
+			if (lookahead < DeflaterConstants.MIN_LOOKAHEAD && !flush)
+			{
+				return false;
+			}
+
+			while (lookahead >= DeflaterConstants.MIN_LOOKAHEAD || flush)
+			{
+				if (lookahead == 0)
+				{
+					if (prevAvailable)
+					{
+						huffman.TallyLit(window[strstart - 1] & 0xff);
+					}
+					prevAvailable = false;
+
+					// We are flushing everything
+#if DebugDeflation
+					if (DeflaterConstants.DEBUGGING && !flush)
+					{
+						throw new SharpZipBaseException("Not flushing, but no lookahead");
+					}
+#endif
+					huffman.FlushBlock(window, blockStart, strstart - blockStart,
+						finish);
+					blockStart = strstart;
+					return false;
+				}
+
+				if (strstart >= 2 * DeflaterConstants.WSIZE - DeflaterConstants.MIN_LOOKAHEAD)
+				{
+					/* slide window, as FindLongestMatch needs this.
+					 * This should only happen when flushing and the window
+					 * is almost full.
+					 */
+					SlideWindow();
+				}
+
+				int prevMatch = matchStart;
+				int prevLen = matchLen;
+				if (lookahead >= DeflaterConstants.MIN_MATCH)
+				{
+					int hashHead = InsertString();
+
+					if (strategy != DeflateStrategy.HuffmanOnly &&
+						hashHead != 0 &&
+						strstart - hashHead <= DeflaterConstants.MAX_DIST &&
+						FindLongestMatch(hashHead))
+					{
+						// longestMatch sets matchStart and matchLen
+
+						// Discard match if too small and too far away
+						if (matchLen <= 5 && (strategy == DeflateStrategy.Filtered || (matchLen == DeflaterConstants.MIN_MATCH && strstart - matchStart > TooFar)))
+						{
+							matchLen = DeflaterConstants.MIN_MATCH - 1;
+						}
+					}
+				}
+
+				// previous match was better
+				if ((prevLen >= DeflaterConstants.MIN_MATCH) && (matchLen <= prevLen))
+				{
+#if DebugDeflation
+					if (DeflaterConstants.DEBUGGING)
+					{
+					   for (int i = 0 ; i < matchLen; i++) {
+						  if (window[strstart-1+i] != window[prevMatch + i])
+							 throw new SharpZipBaseException();
+						}
+					}
+#endif
+					huffman.TallyDist(strstart - 1 - prevMatch, prevLen);
+					prevLen -= 2;
+					do
+					{
+						strstart++;
+						lookahead--;
+						if (lookahead >= DeflaterConstants.MIN_MATCH)
+						{
+							InsertString();
+						}
+					} while (--prevLen > 0);
+
+					strstart++;
+					lookahead--;
+					prevAvailable = false;
+					matchLen = DeflaterConstants.MIN_MATCH - 1;
+				}
+				else
+				{
+					if (prevAvailable)
+					{
+						huffman.TallyLit(window[strstart - 1] & 0xff);
+					}
+					prevAvailable = true;
+					strstart++;
+					lookahead--;
+				}
+
+				if (huffman.IsFull())
+				{
+					int len = strstart - blockStart;
+					if (prevAvailable)
+					{
+						len--;
+					}
+					bool lastBlock = (finish && (lookahead == 0) && !prevAvailable);
+					huffman.FlushBlock(window, blockStart, len, lastBlock);
+					blockStart += len;
+					return !lastBlock;
+				}
+			}
+			return true;
+		}
+
+		#region Instance Fields
+
+		// Hash index of string to be inserted
+		private int ins_h;
+
+		/// <summary>
+		/// Hashtable, hashing three characters to an index for window, so
+		/// that window[index]..window[index+2] have this hash code.
+		/// Note that the array should really be unsigned short, so you need
+		/// to and the values with 0xffff.
+		/// </summary>
+		private short[] head;
+
+		/// <summary>
+		/// <code>prev[index &amp; WMASK]</code> points to the previous index that has the
+		/// same hash code as the string starting at index.  This way
+		/// entries with the same hash code are in a linked list.
+		/// Note that the array should really be unsigned short, so you need
+		/// to and the values with 0xffff.
+		/// </summary>
+		private short[] prev;
+
+		private int matchStart;
+
+		// Length of best match
+		private int matchLen;
+
+		// Set if previous match exists
+		private bool prevAvailable;
+
+		private int blockStart;
+
+		/// <summary>
+		/// Points to the current character in the window.
+		/// </summary>
+		private int strstart;
+
+		/// <summary>
+		/// lookahead is the number of characters starting at strstart in
+		/// window that are valid.
+		/// So window[strstart] until window[strstart+lookahead-1] are valid
+		/// characters.
+		/// </summary>
+		private int lookahead;
+
+		/// <summary>
+		/// This array contains the part of the uncompressed stream that
+		/// is of relevance.  The current character is indexed by strstart.
+		/// </summary>
+		private byte[] window;
+
+		private DeflateStrategy strategy;
+		private int max_chain, max_lazy, niceLength, goodLength;
+
+		/// <summary>
+		/// The current compression function.
+		/// </summary>
+		private int compressionFunction;
+
+		/// <summary>
+		/// The input data for compression.
+		/// </summary>
+		private byte[] inputBuf;
+
+		/// <summary>
+		/// The total bytes of input read.
+		/// </summary>
+		private long totalIn;
+
+		/// <summary>
+		/// The offset into inputBuf, where input data starts.
+		/// </summary>
+		private int inputOff;
+
+		/// <summary>
+		/// The end offset of the input data.
+		/// </summary>
+		private int inputEnd;
+
+		private DeflaterPending pending;
+		private DeflaterHuffman huffman;
+
+		/// <summary>
+		/// The adler checksum
+		/// </summary>
+		private Adler32 adler;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/DeflaterHuffman.cs

@@ -0,0 +1,959 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	/// <summary>
+	/// This is the DeflaterHuffman class.
+	///
+	/// This class is <i>not</i> thread safe.  This is inherent in the API, due
+	/// to the split of Deflate and SetInput.
+	///
+	/// author of the original java version : Jochen Hoenicke
+	/// </summary>
+	public class DeflaterHuffman
+	{
+		private const int BUFSIZE = 1 << (DeflaterConstants.DEFAULT_MEM_LEVEL + 6);
+		private const int LITERAL_NUM = 286;
+
+		// Number of distance codes
+		private const int DIST_NUM = 30;
+
+		// Number of codes used to transfer bit lengths
+		private const int BITLEN_NUM = 19;
+
+		// repeat previous bit length 3-6 times (2 bits of repeat count)
+		private const int REP_3_6 = 16;
+
+		// repeat a zero length 3-10 times  (3 bits of repeat count)
+		private const int REP_3_10 = 17;
+
+		// repeat a zero length 11-138 times  (7 bits of repeat count)
+		private const int REP_11_138 = 18;
+
+		private const int EOF_SYMBOL = 256;
+
+		// The lengths of the bit length codes are sent in order of decreasing
+		// probability, to avoid transmitting the lengths for unused bit length codes.
+		private static readonly int[] BL_ORDER = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
+
+		private static readonly byte[] bit4Reverse = {
+			0,
+			8,
+			4,
+			12,
+			2,
+			10,
+			6,
+			14,
+			1,
+			9,
+			5,
+			13,
+			3,
+			11,
+			7,
+			15
+		};
+
+		private static short[] staticLCodes;
+		private static byte[] staticLLength;
+		private static short[] staticDCodes;
+		private static byte[] staticDLength;
+
+		private class Tree
+		{
+			#region Instance Fields
+
+			public short[] freqs;
+
+			public byte[] length;
+
+			public int minNumCodes;
+
+			public int numCodes;
+
+			private short[] codes;
+			private readonly int[] bl_counts;
+			private readonly int maxLength;
+			private DeflaterHuffman dh;
+
+			#endregion Instance Fields
+
+			#region Constructors
+
+			public Tree(DeflaterHuffman dh, int elems, int minCodes, int maxLength)
+			{
+				this.dh = dh;
+				this.minNumCodes = minCodes;
+				this.maxLength = maxLength;
+				freqs = new short[elems];
+				bl_counts = new int[maxLength];
+			}
+
+			#endregion Constructors
+
+			/// <summary>
+			/// Resets the internal state of the tree
+			/// </summary>
+			public void Reset()
+			{
+				for (int i = 0; i < freqs.Length; i++)
+				{
+					freqs[i] = 0;
+				}
+				codes = null;
+				length = null;
+			}
+
+			public void WriteSymbol(int code)
+			{
+				//				if (DeflaterConstants.DEBUGGING) {
+				//					freqs[code]--;
+				//					//  	  Console.Write("writeSymbol("+freqs.length+","+code+"): ");
+				//				}
+				dh.pending.WriteBits(codes[code] & 0xffff, length[code]);
+			}
+
+			/// <summary>
+			/// Check that all frequencies are zero
+			/// </summary>
+			/// <exception cref="SharpZipBaseException">
+			/// At least one frequency is non-zero
+			/// </exception>
+			public void CheckEmpty()
+			{
+				bool empty = true;
+				for (int i = 0; i < freqs.Length; i++)
+				{
+					empty &= freqs[i] == 0;
+				}
+
+				if (!empty)
+				{
+					throw new SharpZipBaseException("!Empty");
+				}
+			}
+
+			/// <summary>
+			/// Set static codes and length
+			/// </summary>
+			/// <param name="staticCodes">new codes</param>
+			/// <param name="staticLengths">length for new codes</param>
+			public void SetStaticCodes(short[] staticCodes, byte[] staticLengths)
+			{
+				codes = staticCodes;
+				length = staticLengths;
+			}
+
+			/// <summary>
+			/// Build dynamic codes and lengths
+			/// </summary>
+			public void BuildCodes()
+			{
+				int numSymbols = freqs.Length;
+				int[] nextCode = new int[maxLength];
+				int code = 0;
+
+				codes = new short[freqs.Length];
+
+				//				if (DeflaterConstants.DEBUGGING) {
+				//					//Console.WriteLine("buildCodes: "+freqs.Length);
+				//				}
+
+				for (int bits = 0; bits < maxLength; bits++)
+				{
+					nextCode[bits] = code;
+					code += bl_counts[bits] << (15 - bits);
+
+					//					if (DeflaterConstants.DEBUGGING) {
+					//						//Console.WriteLine("bits: " + ( bits + 1) + " count: " + bl_counts[bits]
+					//						                  +" nextCode: "+code);
+					//					}
+				}
+
+#if DebugDeflation
+				if ( DeflaterConstants.DEBUGGING && (code != 65536) )
+				{
+					throw new SharpZipBaseException("Inconsistent bl_counts!");
+				}
+#endif
+				for (int i = 0; i < numCodes; i++)
+				{
+					int bits = length[i];
+					if (bits > 0)
+					{
+						//						if (DeflaterConstants.DEBUGGING) {
+						//								//Console.WriteLine("codes["+i+"] = rev(" + nextCode[bits-1]+"),
+						//								                  +bits);
+						//						}
+
+						codes[i] = BitReverse(nextCode[bits - 1]);
+						nextCode[bits - 1] += 1 << (16 - bits);
+					}
+				}
+			}
+
+			public void BuildTree()
+			{
+				int numSymbols = freqs.Length;
+
+				/* heap is a priority queue, sorted by frequency, least frequent
+				* nodes first.  The heap is a binary tree, with the property, that
+				* the parent node is smaller than both child nodes.  This assures
+				* that the smallest node is the first parent.
+				*
+				* The binary tree is encoded in an array:  0 is root node and
+				* the nodes 2*n+1, 2*n+2 are the child nodes of node n.
+				*/
+				int[] heap = new int[numSymbols];
+				int heapLen = 0;
+				int maxCode = 0;
+				for (int n = 0; n < numSymbols; n++)
+				{
+					int freq = freqs[n];
+					if (freq != 0)
+					{
+						// Insert n into heap
+						int pos = heapLen++;
+						int ppos;
+						while (pos > 0 && freqs[heap[ppos = (pos - 1) / 2]] > freq)
+						{
+							heap[pos] = heap[ppos];
+							pos = ppos;
+						}
+						heap[pos] = n;
+
+						maxCode = n;
+					}
+				}
+
+				/* We could encode a single literal with 0 bits but then we
+				* don't see the literals.  Therefore we force at least two
+				* literals to avoid this case.  We don't care about order in
+				* this case, both literals get a 1 bit code.
+				*/
+				while (heapLen < 2)
+				{
+					int node = maxCode < 2 ? ++maxCode : 0;
+					heap[heapLen++] = node;
+				}
+
+				numCodes = Math.Max(maxCode + 1, minNumCodes);
+
+				int numLeafs = heapLen;
+				int[] childs = new int[4 * heapLen - 2];
+				int[] values = new int[2 * heapLen - 1];
+				int numNodes = numLeafs;
+				for (int i = 0; i < heapLen; i++)
+				{
+					int node = heap[i];
+					childs[2 * i] = node;
+					childs[2 * i + 1] = -1;
+					values[i] = freqs[node] << 8;
+					heap[i] = i;
+				}
+
+				/* Construct the Huffman tree by repeatedly combining the least two
+				* frequent nodes.
+				*/
+				do
+				{
+					int first = heap[0];
+					int last = heap[--heapLen];
+
+					// Propagate the hole to the leafs of the heap
+					int ppos = 0;
+					int path = 1;
+
+					while (path < heapLen)
+					{
+						if (path + 1 < heapLen && values[heap[path]] > values[heap[path + 1]])
+						{
+							path++;
+						}
+
+						heap[ppos] = heap[path];
+						ppos = path;
+						path = path * 2 + 1;
+					}
+
+					/* Now propagate the last element down along path.  Normally
+					* it shouldn't go too deep.
+					*/
+					int lastVal = values[last];
+					while ((path = ppos) > 0 && values[heap[ppos = (path - 1) / 2]] > lastVal)
+					{
+						heap[path] = heap[ppos];
+					}
+					heap[path] = last;
+
+					int second = heap[0];
+
+					// Create a new node father of first and second
+					last = numNodes++;
+					childs[2 * last] = first;
+					childs[2 * last + 1] = second;
+					int mindepth = Math.Min(values[first] & 0xff, values[second] & 0xff);
+					values[last] = lastVal = values[first] + values[second] - mindepth + 1;
+
+					// Again, propagate the hole to the leafs
+					ppos = 0;
+					path = 1;
+
+					while (path < heapLen)
+					{
+						if (path + 1 < heapLen && values[heap[path]] > values[heap[path + 1]])
+						{
+							path++;
+						}
+
+						heap[ppos] = heap[path];
+						ppos = path;
+						path = ppos * 2 + 1;
+					}
+
+					// Now propagate the new element down along path
+					while ((path = ppos) > 0 && values[heap[ppos = (path - 1) / 2]] > lastVal)
+					{
+						heap[path] = heap[ppos];
+					}
+					heap[path] = last;
+				} while (heapLen > 1);
+
+				if (heap[0] != childs.Length / 2 - 1)
+				{
+					throw new SharpZipBaseException("Heap invariant violated");
+				}
+
+				BuildLength(childs);
+			}
+
+			/// <summary>
+			/// Get encoded length
+			/// </summary>
+			/// <returns>Encoded length, the sum of frequencies * lengths</returns>
+			public int GetEncodedLength()
+			{
+				int len = 0;
+				for (int i = 0; i < freqs.Length; i++)
+				{
+					len += freqs[i] * length[i];
+				}
+				return len;
+			}
+
+			/// <summary>
+			/// Scan a literal or distance tree to determine the frequencies of the codes
+			/// in the bit length tree.
+			/// </summary>
+			public void CalcBLFreq(Tree blTree)
+			{
+				int max_count;               /* max repeat count */
+				int min_count;               /* min repeat count */
+				int count;                   /* repeat count of the current code */
+				int curlen = -1;             /* length of current code */
+
+				int i = 0;
+				while (i < numCodes)
+				{
+					count = 1;
+					int nextlen = length[i];
+					if (nextlen == 0)
+					{
+						max_count = 138;
+						min_count = 3;
+					}
+					else
+					{
+						max_count = 6;
+						min_count = 3;
+						if (curlen != nextlen)
+						{
+							blTree.freqs[nextlen]++;
+							count = 0;
+						}
+					}
+					curlen = nextlen;
+					i++;
+
+					while (i < numCodes && curlen == length[i])
+					{
+						i++;
+						if (++count >= max_count)
+						{
+							break;
+						}
+					}
+
+					if (count < min_count)
+					{
+						blTree.freqs[curlen] += (short)count;
+					}
+					else if (curlen != 0)
+					{
+						blTree.freqs[REP_3_6]++;
+					}
+					else if (count <= 10)
+					{
+						blTree.freqs[REP_3_10]++;
+					}
+					else
+					{
+						blTree.freqs[REP_11_138]++;
+					}
+				}
+			}
+
+			/// <summary>
+			/// Write tree values
+			/// </summary>
+			/// <param name="blTree">Tree to write</param>
+			public void WriteTree(Tree blTree)
+			{
+				int max_count;               // max repeat count
+				int min_count;               // min repeat count
+				int count;                   // repeat count of the current code
+				int curlen = -1;             // length of current code
+
+				int i = 0;
+				while (i < numCodes)
+				{
+					count = 1;
+					int nextlen = length[i];
+					if (nextlen == 0)
+					{
+						max_count = 138;
+						min_count = 3;
+					}
+					else
+					{
+						max_count = 6;
+						min_count = 3;
+						if (curlen != nextlen)
+						{
+							blTree.WriteSymbol(nextlen);
+							count = 0;
+						}
+					}
+					curlen = nextlen;
+					i++;
+
+					while (i < numCodes && curlen == length[i])
+					{
+						i++;
+						if (++count >= max_count)
+						{
+							break;
+						}
+					}
+
+					if (count < min_count)
+					{
+						while (count-- > 0)
+						{
+							blTree.WriteSymbol(curlen);
+						}
+					}
+					else if (curlen != 0)
+					{
+						blTree.WriteSymbol(REP_3_6);
+						dh.pending.WriteBits(count - 3, 2);
+					}
+					else if (count <= 10)
+					{
+						blTree.WriteSymbol(REP_3_10);
+						dh.pending.WriteBits(count - 3, 3);
+					}
+					else
+					{
+						blTree.WriteSymbol(REP_11_138);
+						dh.pending.WriteBits(count - 11, 7);
+					}
+				}
+			}
+
+			private void BuildLength(int[] childs)
+			{
+				this.length = new byte[freqs.Length];
+				int numNodes = childs.Length / 2;
+				int numLeafs = (numNodes + 1) / 2;
+				int overflow = 0;
+
+				for (int i = 0; i < maxLength; i++)
+				{
+					bl_counts[i] = 0;
+				}
+
+				// First calculate optimal bit lengths
+				int[] lengths = new int[numNodes];
+				lengths[numNodes - 1] = 0;
+
+				for (int i = numNodes - 1; i >= 0; i--)
+				{
+					if (childs[2 * i + 1] != -1)
+					{
+						int bitLength = lengths[i] + 1;
+						if (bitLength > maxLength)
+						{
+							bitLength = maxLength;
+							overflow++;
+						}
+						lengths[childs[2 * i]] = lengths[childs[2 * i + 1]] = bitLength;
+					}
+					else
+					{
+						// A leaf node
+						int bitLength = lengths[i];
+						bl_counts[bitLength - 1]++;
+						this.length[childs[2 * i]] = (byte)lengths[i];
+					}
+				}
+
+				//				if (DeflaterConstants.DEBUGGING) {
+				//					//Console.WriteLine("Tree "+freqs.Length+" lengths:");
+				//					for (int i=0; i < numLeafs; i++) {
+				//						//Console.WriteLine("Node "+childs[2*i]+" freq: "+freqs[childs[2*i]]
+				//						                  + " len: "+length[childs[2*i]]);
+				//					}
+				//				}
+
+				if (overflow == 0)
+				{
+					return;
+				}
+
+				int incrBitLen = maxLength - 1;
+				do
+				{
+					// Find the first bit length which could increase:
+					while (bl_counts[--incrBitLen] == 0)
+					{
+					}
+
+					// Move this node one down and remove a corresponding
+					// number of overflow nodes.
+					do
+					{
+						bl_counts[incrBitLen]--;
+						bl_counts[++incrBitLen]++;
+						overflow -= 1 << (maxLength - 1 - incrBitLen);
+					} while (overflow > 0 && incrBitLen < maxLength - 1);
+				} while (overflow > 0);
+
+				/* We may have overshot above.  Move some nodes from maxLength to
+				* maxLength-1 in that case.
+				*/
+				bl_counts[maxLength - 1] += overflow;
+				bl_counts[maxLength - 2] -= overflow;
+
+				/* Now recompute all bit lengths, scanning in increasing
+				* frequency.  It is simpler to reconstruct all lengths instead of
+				* fixing only the wrong ones. This idea is taken from 'ar'
+				* written by Haruhiko Okumura.
+				*
+				* The nodes were inserted with decreasing frequency into the childs
+				* array.
+				*/
+				int nodePtr = 2 * numLeafs;
+				for (int bits = maxLength; bits != 0; bits--)
+				{
+					int n = bl_counts[bits - 1];
+					while (n > 0)
+					{
+						int childPtr = 2 * childs[nodePtr++];
+						if (childs[childPtr + 1] == -1)
+						{
+							// We found another leaf
+							length[childs[childPtr]] = (byte)bits;
+							n--;
+						}
+					}
+				}
+				//				if (DeflaterConstants.DEBUGGING) {
+				//					//Console.WriteLine("*** After overflow elimination. ***");
+				//					for (int i=0; i < numLeafs; i++) {
+				//						//Console.WriteLine("Node "+childs[2*i]+" freq: "+freqs[childs[2*i]]
+				//						                  + " len: "+length[childs[2*i]]);
+				//					}
+				//				}
+			}
+		}
+
+		#region Instance Fields
+
+		/// <summary>
+		/// Pending buffer to use
+		/// </summary>
+		public DeflaterPending pending;
+
+		private Tree literalTree;
+		private Tree distTree;
+		private Tree blTree;
+
+		// Buffer for distances
+		private short[] d_buf;
+
+		private byte[] l_buf;
+		private int last_lit;
+		private int extra_bits;
+
+		#endregion Instance Fields
+
+		static DeflaterHuffman()
+		{
+			// See RFC 1951 3.2.6
+			// Literal codes
+			staticLCodes = new short[LITERAL_NUM];
+			staticLLength = new byte[LITERAL_NUM];
+
+			int i = 0;
+			while (i < 144)
+			{
+				staticLCodes[i] = BitReverse((0x030 + i) << 8);
+				staticLLength[i++] = 8;
+			}
+
+			while (i < 256)
+			{
+				staticLCodes[i] = BitReverse((0x190 - 144 + i) << 7);
+				staticLLength[i++] = 9;
+			}
+
+			while (i < 280)
+			{
+				staticLCodes[i] = BitReverse((0x000 - 256 + i) << 9);
+				staticLLength[i++] = 7;
+			}
+
+			while (i < LITERAL_NUM)
+			{
+				staticLCodes[i] = BitReverse((0x0c0 - 280 + i) << 8);
+				staticLLength[i++] = 8;
+			}
+
+			// Distance codes
+			staticDCodes = new short[DIST_NUM];
+			staticDLength = new byte[DIST_NUM];
+			for (i = 0; i < DIST_NUM; i++)
+			{
+				staticDCodes[i] = BitReverse(i << 11);
+				staticDLength[i] = 5;
+			}
+		}
+
+		/// <summary>
+		/// Construct instance with pending buffer
+		/// </summary>
+		/// <param name="pending">Pending buffer to use</param>
+		public DeflaterHuffman(DeflaterPending pending)
+		{
+			this.pending = pending;
+
+			literalTree = new Tree(this, LITERAL_NUM, 257, 15);
+			distTree = new Tree(this, DIST_NUM, 1, 15);
+			blTree = new Tree(this, BITLEN_NUM, 4, 7);
+
+			d_buf = new short[BUFSIZE];
+			l_buf = new byte[BUFSIZE];
+		}
+
+		/// <summary>
+		/// Reset internal state
+		/// </summary>
+		public void Reset()
+		{
+			last_lit = 0;
+			extra_bits = 0;
+			literalTree.Reset();
+			distTree.Reset();
+			blTree.Reset();
+		}
+
+		/// <summary>
+		/// Write all trees to pending buffer
+		/// </summary>
+		/// <param name="blTreeCodes">The number/rank of treecodes to send.</param>
+		public void SendAllTrees(int blTreeCodes)
+		{
+			blTree.BuildCodes();
+			literalTree.BuildCodes();
+			distTree.BuildCodes();
+			pending.WriteBits(literalTree.numCodes - 257, 5);
+			pending.WriteBits(distTree.numCodes - 1, 5);
+			pending.WriteBits(blTreeCodes - 4, 4);
+			for (int rank = 0; rank < blTreeCodes; rank++)
+			{
+				pending.WriteBits(blTree.length[BL_ORDER[rank]], 3);
+			}
+			literalTree.WriteTree(blTree);
+			distTree.WriteTree(blTree);
+
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING) {
+				blTree.CheckEmpty();
+			}
+#endif
+		}
+
+		/// <summary>
+		/// Compress current buffer writing data to pending buffer
+		/// </summary>
+		public void CompressBlock()
+		{
+			for (int i = 0; i < last_lit; i++)
+			{
+				int litlen = l_buf[i] & 0xff;
+				int dist = d_buf[i];
+				if (dist-- != 0)
+				{
+					//					if (DeflaterConstants.DEBUGGING) {
+					//						Console.Write("["+(dist+1)+","+(litlen+3)+"]: ");
+					//					}
+
+					int lc = Lcode(litlen);
+					literalTree.WriteSymbol(lc);
+
+					int bits = (lc - 261) / 4;
+					if (bits > 0 && bits <= 5)
+					{
+						pending.WriteBits(litlen & ((1 << bits) - 1), bits);
+					}
+
+					int dc = Dcode(dist);
+					distTree.WriteSymbol(dc);
+
+					bits = dc / 2 - 1;
+					if (bits > 0)
+					{
+						pending.WriteBits(dist & ((1 << bits) - 1), bits);
+					}
+				}
+				else
+				{
+					//					if (DeflaterConstants.DEBUGGING) {
+					//						if (litlen > 32 && litlen < 127) {
+					//							Console.Write("("+(char)litlen+"): ");
+					//						} else {
+					//							Console.Write("{"+litlen+"}: ");
+					//						}
+					//					}
+					literalTree.WriteSymbol(litlen);
+				}
+			}
+
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING) {
+				Console.Write("EOF: ");
+			}
+#endif
+			literalTree.WriteSymbol(EOF_SYMBOL);
+
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING) {
+				literalTree.CheckEmpty();
+				distTree.CheckEmpty();
+			}
+#endif
+		}
+
+		/// <summary>
+		/// Flush block to output with no compression
+		/// </summary>
+		/// <param name="stored">Data to write</param>
+		/// <param name="storedOffset">Index of first byte to write</param>
+		/// <param name="storedLength">Count of bytes to write</param>
+		/// <param name="lastBlock">True if this is the last block</param>
+		public void FlushStoredBlock(byte[] stored, int storedOffset, int storedLength, bool lastBlock)
+		{
+#if DebugDeflation
+			//			if (DeflaterConstants.DEBUGGING) {
+			//				//Console.WriteLine("Flushing stored block "+ storedLength);
+			//			}
+#endif
+			pending.WriteBits((DeflaterConstants.STORED_BLOCK << 1) + (lastBlock ? 1 : 0), 3);
+			pending.AlignToByte();
+			pending.WriteShort(storedLength);
+			pending.WriteShort(~storedLength);
+			pending.WriteBlock(stored, storedOffset, storedLength);
+			Reset();
+		}
+
+		/// <summary>
+		/// Flush block to output with compression
+		/// </summary>
+		/// <param name="stored">Data to flush</param>
+		/// <param name="storedOffset">Index of first byte to flush</param>
+		/// <param name="storedLength">Count of bytes to flush</param>
+		/// <param name="lastBlock">True if this is the last block</param>
+		public void FlushBlock(byte[] stored, int storedOffset, int storedLength, bool lastBlock)
+		{
+			literalTree.freqs[EOF_SYMBOL]++;
+
+			// Build trees
+			literalTree.BuildTree();
+			distTree.BuildTree();
+
+			// Calculate bitlen frequency
+			literalTree.CalcBLFreq(blTree);
+			distTree.CalcBLFreq(blTree);
+
+			// Build bitlen tree
+			blTree.BuildTree();
+
+			int blTreeCodes = 4;
+			for (int i = 18; i > blTreeCodes; i--)
+			{
+				if (blTree.length[BL_ORDER[i]] > 0)
+				{
+					blTreeCodes = i + 1;
+				}
+			}
+			int opt_len = 14 + blTreeCodes * 3 + blTree.GetEncodedLength() +
+				literalTree.GetEncodedLength() + distTree.GetEncodedLength() +
+				extra_bits;
+
+			int static_len = extra_bits;
+			for (int i = 0; i < LITERAL_NUM; i++)
+			{
+				static_len += literalTree.freqs[i] * staticLLength[i];
+			}
+			for (int i = 0; i < DIST_NUM; i++)
+			{
+				static_len += distTree.freqs[i] * staticDLength[i];
+			}
+			if (opt_len >= static_len)
+			{
+				// Force static trees
+				opt_len = static_len;
+			}
+
+			if (storedOffset >= 0 && storedLength + 4 < opt_len >> 3)
+			{
+				// Store Block
+
+				//				if (DeflaterConstants.DEBUGGING) {
+				//					//Console.WriteLine("Storing, since " + storedLength + " < " + opt_len
+				//					                  + " <= " + static_len);
+				//				}
+				FlushStoredBlock(stored, storedOffset, storedLength, lastBlock);
+			}
+			else if (opt_len == static_len)
+			{
+				// Encode with static tree
+				pending.WriteBits((DeflaterConstants.STATIC_TREES << 1) + (lastBlock ? 1 : 0), 3);
+				literalTree.SetStaticCodes(staticLCodes, staticLLength);
+				distTree.SetStaticCodes(staticDCodes, staticDLength);
+				CompressBlock();
+				Reset();
+			}
+			else
+			{
+				// Encode with dynamic tree
+				pending.WriteBits((DeflaterConstants.DYN_TREES << 1) + (lastBlock ? 1 : 0), 3);
+				SendAllTrees(blTreeCodes);
+				CompressBlock();
+				Reset();
+			}
+		}
+
+		/// <summary>
+		/// Get value indicating if internal buffer is full
+		/// </summary>
+		/// <returns>true if buffer is full</returns>
+		public bool IsFull()
+		{
+			return last_lit >= BUFSIZE;
+		}
+
+		/// <summary>
+		/// Add literal to buffer
+		/// </summary>
+		/// <param name="literal">Literal value to add to buffer.</param>
+		/// <returns>Value indicating internal buffer is full</returns>
+		public bool TallyLit(int literal)
+		{
+			//			if (DeflaterConstants.DEBUGGING) {
+			//				if (lit > 32 && lit < 127) {
+			//					//Console.WriteLine("("+(char)lit+")");
+			//				} else {
+			//					//Console.WriteLine("{"+lit+"}");
+			//				}
+			//			}
+			d_buf[last_lit] = 0;
+			l_buf[last_lit++] = (byte)literal;
+			literalTree.freqs[literal]++;
+			return IsFull();
+		}
+
+		/// <summary>
+		/// Add distance code and length to literal and distance trees
+		/// </summary>
+		/// <param name="distance">Distance code</param>
+		/// <param name="length">Length</param>
+		/// <returns>Value indicating if internal buffer is full</returns>
+		public bool TallyDist(int distance, int length)
+		{
+			//			if (DeflaterConstants.DEBUGGING) {
+			//				//Console.WriteLine("[" + distance + "," + length + "]");
+			//			}
+
+			d_buf[last_lit] = (short)distance;
+			l_buf[last_lit++] = (byte)(length - 3);
+
+			int lc = Lcode(length - 3);
+			literalTree.freqs[lc]++;
+			if (lc >= 265 && lc < 285)
+			{
+				extra_bits += (lc - 261) / 4;
+			}
+
+			int dc = Dcode(distance - 1);
+			distTree.freqs[dc]++;
+			if (dc >= 4)
+			{
+				extra_bits += dc / 2 - 1;
+			}
+			return IsFull();
+		}
+
+		/// <summary>
+		/// Reverse the bits of a 16 bit value.
+		/// </summary>
+		/// <param name="toReverse">Value to reverse bits</param>
+		/// <returns>Value with bits reversed</returns>
+		public static short BitReverse(int toReverse)
+		{
+			return (short)(bit4Reverse[toReverse & 0xF] << 12 |
+							bit4Reverse[(toReverse >> 4) & 0xF] << 8 |
+							bit4Reverse[(toReverse >> 8) & 0xF] << 4 |
+							bit4Reverse[toReverse >> 12]);
+		}
+
+		private static int Lcode(int length)
+		{
+			if (length == 255)
+			{
+				return 285;
+			}
+
+			int code = 257;
+			while (length >= 8)
+			{
+				code += 4;
+				length >>= 1;
+			}
+			return code + length;
+		}
+
+		private static int Dcode(int distance)
+		{
+			int code = 0;
+			while (distance >= 4)
+			{
+				code += 2;
+				distance >>= 1;
+			}
+			return code + distance;
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/DeflaterPending.cs

@@ -0,0 +1,17 @@
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	/// <summary>
+	/// This class stores the pending output of the Deflater.
+	///
+	/// author of the original java version : Jochen Hoenicke
+	/// </summary>
+	public class DeflaterPending : PendingBuffer
+	{
+		/// <summary>
+		/// Construct instance with default buffer size
+		/// </summary>
+		public DeflaterPending() : base(DeflaterConstants.PENDING_BUF_SIZE)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/Inflater.cs

@@ -0,0 +1,887 @@
+using ICSharpCode.SharpZipLib.Checksum;
+using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	/// <summary>
+	/// Inflater is used to decompress data that has been compressed according
+	/// to the "deflate" standard described in rfc1951.
+	///
+	/// By default Zlib (rfc1950) headers and footers are expected in the input.
+	/// You can use constructor <code> public Inflater(bool noHeader)</code> passing true
+	/// if there is no Zlib header information
+	///
+	/// The usage is as following.  First you have to set some input with
+	/// <code>SetInput()</code>, then Inflate() it.  If inflate doesn't
+	/// inflate any bytes there may be three reasons:
+	/// <ul>
+	/// <li>IsNeedingInput() returns true because the input buffer is empty.
+	/// You have to provide more input with <code>SetInput()</code>.
+	/// NOTE: IsNeedingInput() also returns true when, the stream is finished.
+	/// </li>
+	/// <li>IsNeedingDictionary() returns true, you have to provide a preset
+	///    dictionary with <code>SetDictionary()</code>.</li>
+	/// <li>IsFinished returns true, the inflater has finished.</li>
+	/// </ul>
+	/// Once the first output byte is produced, a dictionary will not be
+	/// needed at a later stage.
+	///
+	/// author of the original java version : John Leuner, Jochen Hoenicke
+	/// </summary>
+	public class Inflater
+	{
+		#region Constants/Readonly
+
+		/// <summary>
+		/// Copy lengths for literal codes 257..285
+		/// </summary>
+		private static readonly int[] CPLENS = {
+								  3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
+								  35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258
+							  };
+
+		/// <summary>
+		/// Extra bits for literal codes 257..285
+		/// </summary>
+		private static readonly int[] CPLEXT = {
+								  0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
+								  3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0
+							  };
+
+		/// <summary>
+		/// Copy offsets for distance codes 0..29
+		/// </summary>
+		private static readonly int[] CPDIST = {
+								1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
+								257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
+								8193, 12289, 16385, 24577
+							  };
+
+		/// <summary>
+		/// Extra bits for distance codes
+		/// </summary>
+		private static readonly int[] CPDEXT = {
+								0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
+								7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
+								12, 12, 13, 13
+							  };
+
+		/// <summary>
+		/// These are the possible states for an inflater
+		/// </summary>
+		private const int DECODE_HEADER = 0;
+
+		private const int DECODE_DICT = 1;
+		private const int DECODE_BLOCKS = 2;
+		private const int DECODE_STORED_LEN1 = 3;
+		private const int DECODE_STORED_LEN2 = 4;
+		private const int DECODE_STORED = 5;
+		private const int DECODE_DYN_HEADER = 6;
+		private const int DECODE_HUFFMAN = 7;
+		private const int DECODE_HUFFMAN_LENBITS = 8;
+		private const int DECODE_HUFFMAN_DIST = 9;
+		private const int DECODE_HUFFMAN_DISTBITS = 10;
+		private const int DECODE_CHKSUM = 11;
+		private const int FINISHED = 12;
+
+		#endregion Constants/Readonly
+
+		#region Instance Fields
+
+		/// <summary>
+		/// This variable contains the current state.
+		/// </summary>
+		private int mode;
+
+		/// <summary>
+		/// The adler checksum of the dictionary or of the decompressed
+		/// stream, as it is written in the header resp. footer of the
+		/// compressed stream.
+		/// Only valid if mode is DECODE_DICT or DECODE_CHKSUM.
+		/// </summary>
+		private int readAdler;
+
+		/// <summary>
+		/// The number of bits needed to complete the current state.  This
+		/// is valid, if mode is DECODE_DICT, DECODE_CHKSUM,
+		/// DECODE_HUFFMAN_LENBITS or DECODE_HUFFMAN_DISTBITS.
+		/// </summary>
+		private int neededBits;
+
+		private int repLength;
+		private int repDist;
+		private int uncomprLen;
+
+		/// <summary>
+		/// True, if the last block flag was set in the last block of the
+		/// inflated stream.  This means that the stream ends after the
+		/// current block.
+		/// </summary>
+		private bool isLastBlock;
+
+		/// <summary>
+		/// The total number of inflated bytes.
+		/// </summary>
+		private long totalOut;
+
+		/// <summary>
+		/// The total number of bytes set with setInput().  This is not the
+		/// value returned by the TotalIn property, since this also includes the
+		/// unprocessed input.
+		/// </summary>
+		private long totalIn;
+
+		/// <summary>
+		/// This variable stores the noHeader flag that was given to the constructor.
+		/// True means, that the inflated stream doesn't contain a Zlib header or
+		/// footer.
+		/// </summary>
+		private bool noHeader;
+
+		private readonly StreamManipulator input;
+		private OutputWindow outputWindow;
+		private InflaterDynHeader dynHeader;
+		private InflaterHuffmanTree litlenTree, distTree;
+		private Adler32 adler;
+
+		#endregion Instance Fields
+
+		#region Constructors
+
+		/// <summary>
+		/// Creates a new inflater or RFC1951 decompressor
+		/// RFC1950/Zlib headers and footers will be expected in the input data
+		/// </summary>
+		public Inflater() : this(false)
+		{
+		}
+
+		/// <summary>
+		/// Creates a new inflater.
+		/// </summary>
+		/// <param name="noHeader">
+		/// True if no RFC1950/Zlib header and footer fields are expected in the input data
+		///
+		/// This is used for GZIPed/Zipped input.
+		///
+		/// For compatibility with
+		/// Sun JDK you should provide one byte of input more than needed in
+		/// this case.
+		/// </param>
+		public Inflater(bool noHeader)
+		{
+			this.noHeader = noHeader;
+			if (!noHeader)
+				this.adler = new Adler32();
+			input = new StreamManipulator();
+			outputWindow = new OutputWindow();
+			mode = noHeader ? DECODE_BLOCKS : DECODE_HEADER;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Resets the inflater so that a new stream can be decompressed.  All
+		/// pending input and output will be discarded.
+		/// </summary>
+		public void Reset()
+		{
+			mode = noHeader ? DECODE_BLOCKS : DECODE_HEADER;
+			totalIn = 0;
+			totalOut = 0;
+			input.Reset();
+			outputWindow.Reset();
+			dynHeader = null;
+			litlenTree = null;
+			distTree = null;
+			isLastBlock = false;
+			adler?.Reset();
+		}
+
+		/// <summary>
+		/// Decodes a zlib/RFC1950 header.
+		/// </summary>
+		/// <returns>
+		/// False if more input is needed.
+		/// </returns>
+		/// <exception cref="SharpZipBaseException">
+		/// The header is invalid.
+		/// </exception>
+		private bool DecodeHeader()
+		{
+			int header = input.PeekBits(16);
+			if (header < 0)
+			{
+				return false;
+			}
+			input.DropBits(16);
+
+			// The header is written in "wrong" byte order
+			header = ((header << 8) | (header >> 8)) & 0xffff;
+			if (header % 31 != 0)
+			{
+				throw new SharpZipBaseException("Header checksum illegal");
+			}
+
+			if ((header & 0x0f00) != (Deflater.DEFLATED << 8))
+			{
+				throw new SharpZipBaseException("Compression Method unknown");
+			}
+
+			/* Maximum size of the backwards window in bits.
+			* We currently ignore this, but we could use it to make the
+			* inflater window more space efficient. On the other hand the
+			* full window (15 bits) is needed most times, anyway.
+			int max_wbits = ((header & 0x7000) >> 12) + 8;
+			*/
+
+			if ((header & 0x0020) == 0)
+			{ // Dictionary flag?
+				mode = DECODE_BLOCKS;
+			}
+			else
+			{
+				mode = DECODE_DICT;
+				neededBits = 32;
+			}
+			return true;
+		}
+
+		/// <summary>
+		/// Decodes the dictionary checksum after the deflate header.
+		/// </summary>
+		/// <returns>
+		/// False if more input is needed.
+		/// </returns>
+		private bool DecodeDict()
+		{
+			while (neededBits > 0)
+			{
+				int dictByte = input.PeekBits(8);
+				if (dictByte < 0)
+				{
+					return false;
+				}
+				input.DropBits(8);
+				readAdler = (readAdler << 8) | dictByte;
+				neededBits -= 8;
+			}
+			return false;
+		}
+
+		/// <summary>
+		/// Decodes the huffman encoded symbols in the input stream.
+		/// </summary>
+		/// <returns>
+		/// false if more input is needed, true if output window is
+		/// full or the current block ends.
+		/// </returns>
+		/// <exception cref="SharpZipBaseException">
+		/// if deflated stream is invalid.
+		/// </exception>
+		private bool DecodeHuffman()
+		{
+			int free = outputWindow.GetFreeSpace();
+			while (free >= 258)
+			{
+				int symbol;
+				switch (mode)
+				{
+					case DECODE_HUFFMAN:
+						// This is the inner loop so it is optimized a bit
+						while (((symbol = litlenTree.GetSymbol(input)) & ~0xff) == 0)
+						{
+							outputWindow.Write(symbol);
+							if (--free < 258)
+							{
+								return true;
+							}
+						}
+
+						if (symbol < 257)
+						{
+							if (symbol < 0)
+							{
+								return false;
+							}
+							else
+							{
+								// symbol == 256: end of block
+								distTree = null;
+								litlenTree = null;
+								mode = DECODE_BLOCKS;
+								return true;
+							}
+						}
+
+						try
+						{
+							repLength = CPLENS[symbol - 257];
+							neededBits = CPLEXT[symbol - 257];
+						}
+						catch (Exception)
+						{
+							throw new SharpZipBaseException("Illegal rep length code");
+						}
+						goto case DECODE_HUFFMAN_LENBITS; // fall through
+
+					case DECODE_HUFFMAN_LENBITS:
+						if (neededBits > 0)
+						{
+							mode = DECODE_HUFFMAN_LENBITS;
+							int i = input.PeekBits(neededBits);
+							if (i < 0)
+							{
+								return false;
+							}
+							input.DropBits(neededBits);
+							repLength += i;
+						}
+						mode = DECODE_HUFFMAN_DIST;
+						goto case DECODE_HUFFMAN_DIST; // fall through
+
+					case DECODE_HUFFMAN_DIST:
+						symbol = distTree.GetSymbol(input);
+						if (symbol < 0)
+						{
+							return false;
+						}
+
+						try
+						{
+							repDist = CPDIST[symbol];
+							neededBits = CPDEXT[symbol];
+						}
+						catch (Exception)
+						{
+							throw new SharpZipBaseException("Illegal rep dist code");
+						}
+
+						goto case DECODE_HUFFMAN_DISTBITS; // fall through
+
+					case DECODE_HUFFMAN_DISTBITS:
+						if (neededBits > 0)
+						{
+							mode = DECODE_HUFFMAN_DISTBITS;
+							int i = input.PeekBits(neededBits);
+							if (i < 0)
+							{
+								return false;
+							}
+							input.DropBits(neededBits);
+							repDist += i;
+						}
+
+						outputWindow.Repeat(repLength, repDist);
+						free -= repLength;
+						mode = DECODE_HUFFMAN;
+						break;
+
+					default:
+						throw new SharpZipBaseException("Inflater unknown mode");
+				}
+			}
+			return true;
+		}
+
+		/// <summary>
+		/// Decodes the adler checksum after the deflate stream.
+		/// </summary>
+		/// <returns>
+		/// false if more input is needed.
+		/// </returns>
+		/// <exception cref="SharpZipBaseException">
+		/// If checksum doesn't match.
+		/// </exception>
+		private bool DecodeChksum()
+		{
+			while (neededBits > 0)
+			{
+				int chkByte = input.PeekBits(8);
+				if (chkByte < 0)
+				{
+					return false;
+				}
+				input.DropBits(8);
+				readAdler = (readAdler << 8) | chkByte;
+				neededBits -= 8;
+			}
+
+			if ((int)adler?.Value != readAdler)
+			{
+				throw new SharpZipBaseException("Adler chksum doesn't match: " + (int)adler?.Value + " vs. " + readAdler);
+			}
+
+			mode = FINISHED;
+			return false;
+		}
+
+		/// <summary>
+		/// Decodes the deflated stream.
+		/// </summary>
+		/// <returns>
+		/// false if more input is needed, or if finished.
+		/// </returns>
+		/// <exception cref="SharpZipBaseException">
+		/// if deflated stream is invalid.
+		/// </exception>
+		private bool Decode()
+		{
+			switch (mode)
+			{
+				case DECODE_HEADER:
+					return DecodeHeader();
+
+				case DECODE_DICT:
+					return DecodeDict();
+
+				case DECODE_CHKSUM:
+					return DecodeChksum();
+
+				case DECODE_BLOCKS:
+					if (isLastBlock)
+					{
+						if (noHeader)
+						{
+							mode = FINISHED;
+							return false;
+						}
+						else
+						{
+							input.SkipToByteBoundary();
+							neededBits = 32;
+							mode = DECODE_CHKSUM;
+							return true;
+						}
+					}
+
+					int type = input.PeekBits(3);
+					if (type < 0)
+					{
+						return false;
+					}
+					input.DropBits(3);
+
+					isLastBlock |= (type & 1) != 0;
+					switch (type >> 1)
+					{
+						case DeflaterConstants.STORED_BLOCK:
+							input.SkipToByteBoundary();
+							mode = DECODE_STORED_LEN1;
+							break;
+
+						case DeflaterConstants.STATIC_TREES:
+							litlenTree = InflaterHuffmanTree.defLitLenTree;
+							distTree = InflaterHuffmanTree.defDistTree;
+							mode = DECODE_HUFFMAN;
+							break;
+
+						case DeflaterConstants.DYN_TREES:
+							dynHeader = new InflaterDynHeader(input);
+							mode = DECODE_DYN_HEADER;
+							break;
+
+						default:
+							throw new SharpZipBaseException("Unknown block type " + type);
+					}
+					return true;
+
+				case DECODE_STORED_LEN1:
+					{
+						if ((uncomprLen = input.PeekBits(16)) < 0)
+						{
+							return false;
+						}
+						input.DropBits(16);
+						mode = DECODE_STORED_LEN2;
+					}
+					goto case DECODE_STORED_LEN2; // fall through
+
+				case DECODE_STORED_LEN2:
+					{
+						int nlen = input.PeekBits(16);
+						if (nlen < 0)
+						{
+							return false;
+						}
+						input.DropBits(16);
+						if (nlen != (uncomprLen ^ 0xffff))
+						{
+							throw new SharpZipBaseException("broken uncompressed block");
+						}
+						mode = DECODE_STORED;
+					}
+					goto case DECODE_STORED; // fall through
+
+				case DECODE_STORED:
+					{
+						int more = outputWindow.CopyStored(input, uncomprLen);
+						uncomprLen -= more;
+						if (uncomprLen == 0)
+						{
+							mode = DECODE_BLOCKS;
+							return true;
+						}
+						return !input.IsNeedingInput;
+					}
+
+				case DECODE_DYN_HEADER:
+					if (!dynHeader.AttemptRead())
+					{
+						return false;
+					}
+
+					litlenTree = dynHeader.LiteralLengthTree;
+					distTree = dynHeader.DistanceTree;
+					mode = DECODE_HUFFMAN;
+					goto case DECODE_HUFFMAN; // fall through
+
+				case DECODE_HUFFMAN:
+				case DECODE_HUFFMAN_LENBITS:
+				case DECODE_HUFFMAN_DIST:
+				case DECODE_HUFFMAN_DISTBITS:
+					return DecodeHuffman();
+
+				case FINISHED:
+					return false;
+
+				default:
+					throw new SharpZipBaseException("Inflater.Decode unknown mode");
+			}
+		}
+
+		/// <summary>
+		/// Sets the preset dictionary.  This should only be called, if
+		/// needsDictionary() returns true and it should set the same
+		/// dictionary, that was used for deflating.  The getAdler()
+		/// function returns the checksum of the dictionary needed.
+		/// </summary>
+		/// <param name="buffer">
+		/// The dictionary.
+		/// </param>
+		public void SetDictionary(byte[] buffer)
+		{
+			SetDictionary(buffer, 0, buffer.Length);
+		}
+
+		/// <summary>
+		/// Sets the preset dictionary.  This should only be called, if
+		/// needsDictionary() returns true and it should set the same
+		/// dictionary, that was used for deflating.  The getAdler()
+		/// function returns the checksum of the dictionary needed.
+		/// </summary>
+		/// <param name="buffer">
+		/// The dictionary.
+		/// </param>
+		/// <param name="index">
+		/// The index into buffer where the dictionary starts.
+		/// </param>
+		/// <param name="count">
+		/// The number of bytes in the dictionary.
+		/// </param>
+		/// <exception cref="System.InvalidOperationException">
+		/// No dictionary is needed.
+		/// </exception>
+		/// <exception cref="SharpZipBaseException">
+		/// The adler checksum for the buffer is invalid
+		/// </exception>
+		public void SetDictionary(byte[] buffer, int index, int count)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			if (index < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(index));
+			}
+
+			if (count < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(count));
+			}
+
+			if (!IsNeedingDictionary)
+			{
+				throw new InvalidOperationException("Dictionary is not needed");
+			}
+
+			adler?.Update(new ArraySegment<byte>(buffer, index, count));
+
+			if (adler != null && (int)adler.Value != readAdler)
+			{
+				throw new SharpZipBaseException("Wrong adler checksum");
+			}
+			adler?.Reset();
+			outputWindow.CopyDict(buffer, index, count);
+			mode = DECODE_BLOCKS;
+		}
+
+		/// <summary>
+		/// Sets the input.  This should only be called, if needsInput()
+		/// returns true.
+		/// </summary>
+		/// <param name="buffer">
+		/// the input.
+		/// </param>
+		public void SetInput(byte[] buffer)
+		{
+			SetInput(buffer, 0, buffer.Length);
+		}
+
+		/// <summary>
+		/// Sets the input.  This should only be called, if needsInput()
+		/// returns true.
+		/// </summary>
+		/// <param name="buffer">
+		/// The source of input data
+		/// </param>
+		/// <param name="index">
+		/// The index into buffer where the input starts.
+		/// </param>
+		/// <param name="count">
+		/// The number of bytes of input to use.
+		/// </param>
+		/// <exception cref="System.InvalidOperationException">
+		/// No input is needed.
+		/// </exception>
+		/// <exception cref="System.ArgumentOutOfRangeException">
+		/// The index and/or count are wrong.
+		/// </exception>
+		public void SetInput(byte[] buffer, int index, int count)
+		{
+			input.SetInput(buffer, index, count);
+			totalIn += (long)count;
+		}
+
+		/// <summary>
+		/// Inflates the compressed stream to the output buffer.  If this
+		/// returns 0, you should check, whether IsNeedingDictionary(),
+		/// IsNeedingInput() or IsFinished() returns true, to determine why no
+		/// further output is produced.
+		/// </summary>
+		/// <param name="buffer">
+		/// the output buffer.
+		/// </param>
+		/// <returns>
+		/// The number of bytes written to the buffer, 0 if no further
+		/// output can be produced.
+		/// </returns>
+		/// <exception cref="System.ArgumentOutOfRangeException">
+		/// if buffer has length 0.
+		/// </exception>
+		/// <exception cref="System.FormatException">
+		/// if deflated stream is invalid.
+		/// </exception>
+		public int Inflate(byte[] buffer)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			return Inflate(buffer, 0, buffer.Length);
+		}
+
+		/// <summary>
+		/// Inflates the compressed stream to the output buffer.  If this
+		/// returns 0, you should check, whether needsDictionary(),
+		/// needsInput() or finished() returns true, to determine why no
+		/// further output is produced.
+		/// </summary>
+		/// <param name="buffer">
+		/// the output buffer.
+		/// </param>
+		/// <param name="offset">
+		/// the offset in buffer where storing starts.
+		/// </param>
+		/// <param name="count">
+		/// the maximum number of bytes to output.
+		/// </param>
+		/// <returns>
+		/// the number of bytes written to the buffer, 0 if no further output can be produced.
+		/// </returns>
+		/// <exception cref="System.ArgumentOutOfRangeException">
+		/// if count is less than 0.
+		/// </exception>
+		/// <exception cref="System.ArgumentOutOfRangeException">
+		/// if the index and / or count are wrong.
+		/// </exception>
+		/// <exception cref="System.FormatException">
+		/// if deflated stream is invalid.
+		/// </exception>
+		public int Inflate(byte[] buffer, int offset, int count)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			if (count < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(count), "count cannot be negative");
+			}
+
+			if (offset < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset), "offset cannot be negative");
+			}
+
+			if (offset + count > buffer.Length)
+			{
+				throw new ArgumentException("count exceeds buffer bounds");
+			}
+
+			// Special case: count may be zero
+			if (count == 0)
+			{
+				if (!IsFinished)
+				{ // -jr- 08-Nov-2003 INFLATE_BUG fix..
+					Decode();
+				}
+				return 0;
+			}
+
+			int bytesCopied = 0;
+
+			do
+			{
+				if (mode != DECODE_CHKSUM)
+				{
+					/* Don't give away any output, if we are waiting for the
+					* checksum in the input stream.
+					*
+					* With this trick we have always:
+					*   IsNeedingInput() and not IsFinished()
+					*   implies more output can be produced.
+					*/
+					int more = outputWindow.CopyOutput(buffer, offset, count);
+					if (more > 0)
+					{
+						adler?.Update(new ArraySegment<byte>(buffer, offset, more));
+						offset += more;
+						bytesCopied += more;
+						totalOut += (long)more;
+						count -= more;
+						if (count == 0)
+						{
+							return bytesCopied;
+						}
+					}
+				}
+			} while (Decode() || ((outputWindow.GetAvailable() > 0) && (mode != DECODE_CHKSUM)));
+			return bytesCopied;
+		}
+
+		/// <summary>
+		/// Returns true, if the input buffer is empty.
+		/// You should then call setInput().
+		/// NOTE: This method also returns true when the stream is finished.
+		/// </summary>
+		public bool IsNeedingInput
+		{
+			get
+			{
+				return input.IsNeedingInput;
+			}
+		}
+
+		/// <summary>
+		/// Returns true, if a preset dictionary is needed to inflate the input.
+		/// </summary>
+		public bool IsNeedingDictionary
+		{
+			get
+			{
+				return mode == DECODE_DICT && neededBits == 0;
+			}
+		}
+
+		/// <summary>
+		/// Returns true, if the inflater has finished.  This means, that no
+		/// input is needed and no output can be produced.
+		/// </summary>
+		public bool IsFinished
+		{
+			get
+			{
+				return mode == FINISHED && outputWindow.GetAvailable() == 0;
+			}
+		}
+
+		/// <summary>
+		/// Gets the adler checksum.  This is either the checksum of all
+		/// uncompressed bytes returned by inflate(), or if needsDictionary()
+		/// returns true (and thus no output was yet produced) this is the
+		/// adler checksum of the expected dictionary.
+		/// </summary>
+		/// <returns>
+		/// the adler checksum.
+		/// </returns>
+		public int Adler
+		{
+			get
+			{
+				if (IsNeedingDictionary)
+				{
+					return readAdler;
+				}
+				else if (adler != null)
+				{
+					return (int)adler.Value;
+				}
+				else
+				{
+					return 0;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Gets the total number of output bytes returned by Inflate().
+		/// </summary>
+		/// <returns>
+		/// the total number of output bytes.
+		/// </returns>
+		public long TotalOut
+		{
+			get
+			{
+				return totalOut;
+			}
+		}
+
+		/// <summary>
+		/// Gets the total number of processed compressed input bytes.
+		/// </summary>
+		/// <returns>
+		/// The total number of bytes of processed input bytes.
+		/// </returns>
+		public long TotalIn
+		{
+			get
+			{
+				return totalIn - (long)RemainingInput;
+			}
+		}
+
+		/// <summary>
+		/// Gets the number of unprocessed input bytes.  Useful, if the end of the
+		/// stream is reached and you want to further process the bytes after
+		/// the deflate stream.
+		/// </summary>
+		/// <returns>
+		/// The number of bytes of the input which have not been processed.
+		/// </returns>
+		public int RemainingInput
+		{
+			// TODO: This should be a long?
+			get
+			{
+				return input.AvailableBytes;
+			}
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/InflaterDynHeader.cs

@@ -0,0 +1,151 @@
+using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
+using System;
+using System.Collections.Generic;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	internal class InflaterDynHeader
+	{
+		#region Constants
+
+		// maximum number of literal/length codes
+		private const int LITLEN_MAX = 286;
+
+		// maximum number of distance codes
+		private const int DIST_MAX = 30;
+
+		// maximum data code lengths to read
+		private const int CODELEN_MAX = LITLEN_MAX + DIST_MAX;
+
+		// maximum meta code length codes to read
+		private const int META_MAX = 19;
+
+		private static readonly int[] MetaCodeLengthIndex =
+			{ 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
+
+		#endregion Constants
+
+		/// <summary>
+		/// Continue decoding header from <see cref="input"/> until more bits are needed or decoding has been completed
+		/// </summary>
+		/// <returns>Returns whether decoding could be completed</returns>
+		public bool AttemptRead()
+			=> !state.MoveNext() || state.Current;
+
+		public InflaterDynHeader(StreamManipulator input)
+		{
+			this.input = input;
+			stateMachine = CreateStateMachine();
+			state = stateMachine.GetEnumerator();
+		}
+
+		private IEnumerable<bool> CreateStateMachine()
+		{
+			// Read initial code length counts from header
+			while (!input.TryGetBits(5, ref litLenCodeCount, 257)) yield return false;
+			while (!input.TryGetBits(5, ref distanceCodeCount, 1)) yield return false;
+			while (!input.TryGetBits(4, ref metaCodeCount, 4)) yield return false;
+			var dataCodeCount = litLenCodeCount + distanceCodeCount;
+
+			if (litLenCodeCount > LITLEN_MAX) throw new ValueOutOfRangeException(nameof(litLenCodeCount));
+			if (distanceCodeCount > DIST_MAX) throw new ValueOutOfRangeException(nameof(distanceCodeCount));
+			if (metaCodeCount > META_MAX) throw new ValueOutOfRangeException(nameof(metaCodeCount));
+
+			// Load code lengths for the meta tree from the header bits
+			for (int i = 0; i < metaCodeCount; i++)
+			{
+				while (!input.TryGetBits(3, ref codeLengths, MetaCodeLengthIndex[i])) yield return false;
+			}
+
+			var metaCodeTree = new InflaterHuffmanTree(codeLengths);
+
+			// Decompress the meta tree symbols into the data table code lengths
+			int index = 0;
+			while (index < dataCodeCount)
+			{
+				byte codeLength;
+				int symbol;
+
+				while ((symbol = metaCodeTree.GetSymbol(input)) < 0) yield return false;
+
+				if (symbol < 16)
+				{
+					// append literal code length
+					codeLengths[index++] = (byte)symbol;
+				}
+				else
+				{
+					int repeatCount = 0;
+
+					if (symbol == 16) // Repeat last code length 3..6 times
+					{
+						if (index == 0)
+							throw new StreamDecodingException("Cannot repeat previous code length when no other code length has been read");
+
+						codeLength = codeLengths[index - 1];
+
+						// 2 bits + 3, [3..6]
+						while (!input.TryGetBits(2, ref repeatCount, 3)) yield return false;
+					}
+					else if (symbol == 17) // Repeat zero 3..10 times
+					{
+						codeLength = 0;
+
+						// 3 bits + 3, [3..10]
+						while (!input.TryGetBits(3, ref repeatCount, 3)) yield return false;
+					}
+					else // (symbol == 18), Repeat zero 11..138 times
+					{
+						codeLength = 0;
+
+						// 7 bits + 11, [11..138]
+						while (!input.TryGetBits(7, ref repeatCount, 11)) yield return false;
+					}
+
+					if (index + repeatCount > dataCodeCount)
+						throw new StreamDecodingException("Cannot repeat code lengths past total number of data code lengths");
+
+					while (repeatCount-- > 0)
+						codeLengths[index++] = codeLength;
+				}
+			}
+
+			if (codeLengths[256] == 0)
+				throw new StreamDecodingException("Inflater dynamic header end-of-block code missing");
+
+			litLenTree = new InflaterHuffmanTree(new ArraySegment<byte>(codeLengths, 0, litLenCodeCount));
+			distTree = new InflaterHuffmanTree(new ArraySegment<byte>(codeLengths, litLenCodeCount, distanceCodeCount));
+
+			yield return true;
+		}
+
+		/// <summary>
+		/// Get literal/length huffman tree, must not be used before <see cref="AttemptRead"/> has returned true
+		/// </summary>
+		/// <exception cref="StreamDecodingException">If hader has not been successfully read by the state machine</exception>
+		public InflaterHuffmanTree LiteralLengthTree
+			=> litLenTree ?? throw new StreamDecodingException("Header properties were accessed before header had been successfully read");
+
+		/// <summary>
+		/// Get distance huffman tree, must not be used before <see cref="AttemptRead"/> has returned true
+		/// </summary>
+		/// <exception cref="StreamDecodingException">If hader has not been successfully read by the state machine</exception>
+		public InflaterHuffmanTree DistanceTree
+			=> distTree ?? throw new StreamDecodingException("Header properties were accessed before header had been successfully read");
+
+		#region Instance Fields
+
+		private readonly StreamManipulator input;
+		private readonly IEnumerator<bool> state;
+		private readonly IEnumerable<bool> stateMachine;
+
+		private byte[] codeLengths = new byte[CODELEN_MAX];
+
+		private InflaterHuffmanTree litLenTree;
+		private InflaterHuffmanTree distTree;
+
+		private int litLenCodeCount, distanceCodeCount, metaCodeCount;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/InflaterHuffmanTree.cs

@@ -0,0 +1,237 @@
+using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
+using System;
+using System.Collections.Generic;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	/// <summary>
+	/// Huffman tree used for inflation
+	/// </summary>
+	public class InflaterHuffmanTree
+	{
+		#region Constants
+
+		private const int MAX_BITLEN = 15;
+
+		#endregion Constants
+
+		#region Instance Fields
+
+		private short[] tree;
+
+		#endregion Instance Fields
+
+		/// <summary>
+		/// Literal length tree
+		/// </summary>
+		public static InflaterHuffmanTree defLitLenTree;
+
+		/// <summary>
+		/// Distance tree
+		/// </summary>
+		public static InflaterHuffmanTree defDistTree;
+
+		static InflaterHuffmanTree()
+		{
+			try
+			{
+				byte[] codeLengths = new byte[288];
+				int i = 0;
+				while (i < 144)
+				{
+					codeLengths[i++] = 8;
+				}
+				while (i < 256)
+				{
+					codeLengths[i++] = 9;
+				}
+				while (i < 280)
+				{
+					codeLengths[i++] = 7;
+				}
+				while (i < 288)
+				{
+					codeLengths[i++] = 8;
+				}
+				defLitLenTree = new InflaterHuffmanTree(codeLengths);
+
+				codeLengths = new byte[32];
+				i = 0;
+				while (i < 32)
+				{
+					codeLengths[i++] = 5;
+				}
+				defDistTree = new InflaterHuffmanTree(codeLengths);
+			}
+			catch (Exception)
+			{
+				throw new SharpZipBaseException("InflaterHuffmanTree: static tree length illegal");
+			}
+		}
+
+		#region Constructors
+
+		/// <summary>
+		/// Constructs a Huffman tree from the array of code lengths.
+		/// </summary>
+		/// <param name = "codeLengths">
+		/// the array of code lengths
+		/// </param>
+		public InflaterHuffmanTree(IList<byte> codeLengths)
+		{
+			BuildTree(codeLengths);
+		}
+
+		#endregion Constructors
+
+		private void BuildTree(IList<byte> codeLengths)
+		{
+			int[] blCount = new int[MAX_BITLEN + 1];
+			int[] nextCode = new int[MAX_BITLEN + 1];
+
+			for (int i = 0; i < codeLengths.Count; i++)
+			{
+				int bits = codeLengths[i];
+				if (bits > 0)
+				{
+					blCount[bits]++;
+				}
+			}
+
+			int code = 0;
+			int treeSize = 512;
+			for (int bits = 1; bits <= MAX_BITLEN; bits++)
+			{
+				nextCode[bits] = code;
+				code += blCount[bits] << (16 - bits);
+				if (bits >= 10)
+				{
+					/* We need an extra table for bit lengths >= 10. */
+					int start = nextCode[bits] & 0x1ff80;
+					int end = code & 0x1ff80;
+					treeSize += (end - start) >> (16 - bits);
+				}
+			}
+
+			/* -jr comment this out! doesnt work for dynamic trees and pkzip 2.04g
+						if (code != 65536)
+						{
+							throw new SharpZipBaseException("Code lengths don't add up properly.");
+						}
+			*/
+			/* Now create and fill the extra tables from longest to shortest
+			* bit len.  This way the sub trees will be aligned.
+			*/
+			tree = new short[treeSize];
+			int treePtr = 512;
+			for (int bits = MAX_BITLEN; bits >= 10; bits--)
+			{
+				int end = code & 0x1ff80;
+				code -= blCount[bits] << (16 - bits);
+				int start = code & 0x1ff80;
+				for (int i = start; i < end; i += 1 << 7)
+				{
+					tree[DeflaterHuffman.BitReverse(i)] = (short)((-treePtr << 4) | bits);
+					treePtr += 1 << (bits - 9);
+				}
+			}
+
+			for (int i = 0; i < codeLengths.Count; i++)
+			{
+				int bits = codeLengths[i];
+				if (bits == 0)
+				{
+					continue;
+				}
+				code = nextCode[bits];
+				int revcode = DeflaterHuffman.BitReverse(code);
+				if (bits <= 9)
+				{
+					do
+					{
+						tree[revcode] = (short)((i << 4) | bits);
+						revcode += 1 << bits;
+					} while (revcode < 512);
+				}
+				else
+				{
+					int subTree = tree[revcode & 511];
+					int treeLen = 1 << (subTree & 15);
+					subTree = -(subTree >> 4);
+					do
+					{
+						tree[subTree | (revcode >> 9)] = (short)((i << 4) | bits);
+						revcode += 1 << bits;
+					} while (revcode < treeLen);
+				}
+				nextCode[bits] = code + (1 << (16 - bits));
+			}
+		}
+
+		/// <summary>
+		/// Reads the next symbol from input.  The symbol is encoded using the
+		/// huffman tree.
+		/// </summary>
+		/// <param name="input">
+		/// input the input source.
+		/// </param>
+		/// <returns>
+		/// the next symbol, or -1 if not enough input is available.
+		/// </returns>
+		public int GetSymbol(StreamManipulator input)
+		{
+			int lookahead, symbol;
+			if ((lookahead = input.PeekBits(9)) >= 0)
+			{
+                symbol = tree[lookahead];
+				int bitlen = symbol & 15;
+
+				if (symbol >= 0)
+				{
+                    if(bitlen == 0){
+                        throw new SharpZipBaseException("Encountered invalid codelength 0");
+                    } 
+					input.DropBits(bitlen);
+					return symbol >> 4;
+				}
+				int subtree = -(symbol >> 4);
+				if ((lookahead = input.PeekBits(bitlen)) >= 0)
+				{
+					symbol = tree[subtree | (lookahead >> 9)];
+					input.DropBits(symbol & 15);
+					return symbol >> 4;
+				}
+				else
+				{
+					int bits = input.AvailableBits;
+					lookahead = input.PeekBits(bits);
+					symbol = tree[subtree | (lookahead >> 9)];
+					if ((symbol & 15) <= bits)
+					{
+						input.DropBits(symbol & 15);
+						return symbol >> 4;
+					}
+					else
+					{
+						return -1;
+					}
+				}
+			}
+			else // Less than 9 bits
+			{
+				int bits = input.AvailableBits;
+				lookahead = input.PeekBits(bits);
+				symbol = tree[lookahead];
+				if (symbol >= 0 && (symbol & 15) <= bits)
+				{
+					input.DropBits(symbol & 15);
+					return symbol >> 4;
+				}
+				else
+				{
+					return -1;
+				}
+			}
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/PendingBuffer.cs

@@ -0,0 +1,268 @@
+namespace ICSharpCode.SharpZipLib.Zip.Compression
+{
+	/// <summary>
+	/// This class is general purpose class for writing data to a buffer.
+	///
+	/// It allows you to write bits as well as bytes
+	/// Based on DeflaterPending.java
+	///
+	/// author of the original java version : Jochen Hoenicke
+	/// </summary>
+	public class PendingBuffer
+	{
+		#region Instance Fields
+
+		/// <summary>
+		/// Internal work buffer
+		/// </summary>
+		private readonly byte[] buffer;
+
+		private int start;
+		private int end;
+
+		private uint bits;
+		private int bitCount;
+
+		#endregion Instance Fields
+
+		#region Constructors
+
+		/// <summary>
+		/// construct instance using default buffer size of 4096
+		/// </summary>
+		public PendingBuffer() : this(4096)
+		{
+		}
+
+		/// <summary>
+		/// construct instance using specified buffer size
+		/// </summary>
+		/// <param name="bufferSize">
+		/// size to use for internal buffer
+		/// </param>
+		public PendingBuffer(int bufferSize)
+		{
+			buffer = new byte[bufferSize];
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Clear internal state/buffers
+		/// </summary>
+		public void Reset()
+		{
+			start = end = bitCount = 0;
+		}
+
+		/// <summary>
+		/// Write a byte to buffer
+		/// </summary>
+		/// <param name="value">
+		/// The value to write
+		/// </param>
+		public void WriteByte(int value)
+		{
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING && (start != 0) )
+			{
+				throw new SharpZipBaseException("Debug check: start != 0");
+			}
+#endif
+			buffer[end++] = unchecked((byte)value);
+		}
+
+		/// <summary>
+		/// Write a short value to buffer LSB first
+		/// </summary>
+		/// <param name="value">
+		/// The value to write.
+		/// </param>
+		public void WriteShort(int value)
+		{
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING && (start != 0) )
+			{
+				throw new SharpZipBaseException("Debug check: start != 0");
+			}
+#endif
+			buffer[end++] = unchecked((byte)value);
+			buffer[end++] = unchecked((byte)(value >> 8));
+		}
+
+		/// <summary>
+		/// write an integer LSB first
+		/// </summary>
+		/// <param name="value">The value to write.</param>
+		public void WriteInt(int value)
+		{
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING && (start != 0) )
+			{
+				throw new SharpZipBaseException("Debug check: start != 0");
+			}
+#endif
+			buffer[end++] = unchecked((byte)value);
+			buffer[end++] = unchecked((byte)(value >> 8));
+			buffer[end++] = unchecked((byte)(value >> 16));
+			buffer[end++] = unchecked((byte)(value >> 24));
+		}
+
+		/// <summary>
+		/// Write a block of data to buffer
+		/// </summary>
+		/// <param name="block">data to write</param>
+		/// <param name="offset">offset of first byte to write</param>
+		/// <param name="length">number of bytes to write</param>
+		public void WriteBlock(byte[] block, int offset, int length)
+		{
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING && (start != 0) )
+			{
+				throw new SharpZipBaseException("Debug check: start != 0");
+			}
+#endif
+			System.Array.Copy(block, offset, buffer, end, length);
+			end += length;
+		}
+
+		/// <summary>
+		/// The number of bits written to the buffer
+		/// </summary>
+		public int BitCount
+		{
+			get
+			{
+				return bitCount;
+			}
+		}
+
+		/// <summary>
+		/// Align internal buffer on a byte boundary
+		/// </summary>
+		public void AlignToByte()
+		{
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING && (start != 0) )
+			{
+				throw new SharpZipBaseException("Debug check: start != 0");
+			}
+#endif
+			if (bitCount > 0)
+			{
+				buffer[end++] = unchecked((byte)bits);
+				if (bitCount > 8)
+				{
+					buffer[end++] = unchecked((byte)(bits >> 8));
+				}
+			}
+			bits = 0;
+			bitCount = 0;
+		}
+
+		/// <summary>
+		/// Write bits to internal buffer
+		/// </summary>
+		/// <param name="b">source of bits</param>
+		/// <param name="count">number of bits to write</param>
+		public void WriteBits(int b, int count)
+		{
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING && (start != 0) )
+			{
+				throw new SharpZipBaseException("Debug check: start != 0");
+			}
+
+			//			if (DeflaterConstants.DEBUGGING) {
+			//				//Console.WriteLine("writeBits("+b+","+count+")");
+			//			}
+#endif
+			bits |= (uint)(b << bitCount);
+			bitCount += count;
+			if (bitCount >= 16)
+			{
+				buffer[end++] = unchecked((byte)bits);
+				buffer[end++] = unchecked((byte)(bits >> 8));
+				bits >>= 16;
+				bitCount -= 16;
+			}
+		}
+
+		/// <summary>
+		/// Write a short value to internal buffer most significant byte first
+		/// </summary>
+		/// <param name="s">value to write</param>
+		public void WriteShortMSB(int s)
+		{
+#if DebugDeflation
+			if (DeflaterConstants.DEBUGGING && (start != 0) )
+			{
+				throw new SharpZipBaseException("Debug check: start != 0");
+			}
+#endif
+			buffer[end++] = unchecked((byte)(s >> 8));
+			buffer[end++] = unchecked((byte)s);
+		}
+
+		/// <summary>
+		/// Indicates if buffer has been flushed
+		/// </summary>
+		public bool IsFlushed
+		{
+			get
+			{
+				return end == 0;
+			}
+		}
+
+		/// <summary>
+		/// Flushes the pending buffer into the given output array.  If the
+		/// output array is to small, only a partial flush is done.
+		/// </summary>
+		/// <param name="output">The output array.</param>
+		/// <param name="offset">The offset into output array.</param>
+		/// <param name="length">The maximum number of bytes to store.</param>
+		/// <returns>The number of bytes flushed.</returns>
+		public int Flush(byte[] output, int offset, int length)
+		{
+			if (bitCount >= 8)
+			{
+				buffer[end++] = unchecked((byte)bits);
+				bits >>= 8;
+				bitCount -= 8;
+			}
+
+			if (length > end - start)
+			{
+				length = end - start;
+				System.Array.Copy(buffer, start, output, offset, length);
+				start = 0;
+				end = 0;
+			}
+			else
+			{
+				System.Array.Copy(buffer, start, output, offset, length);
+				start += length;
+			}
+			return length;
+		}
+
+		/// <summary>
+		/// Convert internal buffer to byte array.
+		/// Buffer is empty on completion
+		/// </summary>
+		/// <returns>
+		/// The internal buffer contents converted to a byte array.
+		/// </returns>
+		public byte[] ToByteArray()
+		{
+			AlignToByte();
+
+			byte[] result = new byte[end - start];
+			System.Array.Copy(buffer, start, result, 0, result.Length);
+			start = 0;
+			end = 0;
+			return result;
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/Streams/DeflaterOutputStream.cs

@@ -0,0 +1,490 @@
+using ICSharpCode.SharpZipLib.Encryption;
+using System;
+using System.IO;
+using System.Security.Cryptography;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression.Streams
+{
+	/// <summary>
+	/// A special stream deflating or compressing the bytes that are
+	/// written to it.  It uses a Deflater to perform actual deflating.<br/>
+	/// Authors of the original java version : Tom Tromey, Jochen Hoenicke
+	/// </summary>
+	public class DeflaterOutputStream : Stream
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Creates a new DeflaterOutputStream with a default Deflater and default buffer size.
+		/// </summary>
+		/// <param name="baseOutputStream">
+		/// the output stream where deflated output should be written.
+		/// </param>
+		public DeflaterOutputStream(Stream baseOutputStream)
+			: this(baseOutputStream, new Deflater(), 512)
+		{
+		}
+
+		/// <summary>
+		/// Creates a new DeflaterOutputStream with the given Deflater and
+		/// default buffer size.
+		/// </summary>
+		/// <param name="baseOutputStream">
+		/// the output stream where deflated output should be written.
+		/// </param>
+		/// <param name="deflater">
+		/// the underlying deflater.
+		/// </param>
+		public DeflaterOutputStream(Stream baseOutputStream, Deflater deflater)
+			: this(baseOutputStream, deflater, 512)
+		{
+		}
+
+		/// <summary>
+		/// Creates a new DeflaterOutputStream with the given Deflater and
+		/// buffer size.
+		/// </summary>
+		/// <param name="baseOutputStream">
+		/// The output stream where deflated output is written.
+		/// </param>
+		/// <param name="deflater">
+		/// The underlying deflater to use
+		/// </param>
+		/// <param name="bufferSize">
+		/// The buffer size in bytes to use when deflating (minimum value 512)
+		/// </param>
+		/// <exception cref="ArgumentOutOfRangeException">
+		/// bufsize is less than or equal to zero.
+		/// </exception>
+		/// <exception cref="ArgumentException">
+		/// baseOutputStream does not support writing
+		/// </exception>
+		/// <exception cref="ArgumentNullException">
+		/// deflater instance is null
+		/// </exception>
+		public DeflaterOutputStream(Stream baseOutputStream, Deflater deflater, int bufferSize)
+		{
+			if (baseOutputStream == null)
+			{
+				throw new ArgumentNullException(nameof(baseOutputStream));
+			}
+
+			if (baseOutputStream.CanWrite == false)
+			{
+				throw new ArgumentException("Must support writing", nameof(baseOutputStream));
+			}
+
+			if (bufferSize < 512)
+			{
+				throw new ArgumentOutOfRangeException(nameof(bufferSize));
+			}
+
+			baseOutputStream_ = baseOutputStream;
+			buffer_ = new byte[bufferSize];
+			deflater_ = deflater ?? throw new ArgumentNullException(nameof(deflater));
+		}
+
+		#endregion Constructors
+
+		#region Public API
+
+		/// <summary>
+		/// Finishes the stream by calling finish() on the deflater.
+		/// </summary>
+		/// <exception cref="SharpZipBaseException">
+		/// Not all input is deflated
+		/// </exception>
+		public virtual void Finish()
+		{
+			deflater_.Finish();
+			while (!deflater_.IsFinished)
+			{
+				int len = deflater_.Deflate(buffer_, 0, buffer_.Length);
+				if (len <= 0)
+				{
+					break;
+				}
+
+				if (cryptoTransform_ != null)
+				{
+					EncryptBlock(buffer_, 0, len);
+				}
+
+				baseOutputStream_.Write(buffer_, 0, len);
+			}
+
+			if (!deflater_.IsFinished)
+			{
+				throw new SharpZipBaseException("Can't deflate all input?");
+			}
+
+			baseOutputStream_.Flush();
+
+			if (cryptoTransform_ != null)
+			{
+				if (cryptoTransform_ is ZipAESTransform)
+				{
+					AESAuthCode = ((ZipAESTransform)cryptoTransform_).GetAuthCode();
+				}
+				cryptoTransform_.Dispose();
+				cryptoTransform_ = null;
+			}
+		}
+
+		/// <summary>
+		/// Gets or sets a flag indicating ownership of underlying stream.
+		/// When the flag is true <see cref="Stream.Dispose()" /> will close the underlying stream also.
+		/// </summary>
+		/// <remarks>The default value is true.</remarks>
+		public bool IsStreamOwner { get; set; } = true;
+
+		///	<summary>
+		/// Allows client to determine if an entry can be patched after its added
+		/// </summary>
+		public bool CanPatchEntries
+		{
+			get
+			{
+				return baseOutputStream_.CanSeek;
+			}
+		}
+
+		#endregion Public API
+
+		#region Encryption
+
+		private string password;
+
+		private ICryptoTransform cryptoTransform_;
+
+		/// <summary>
+		/// Returns the 10 byte AUTH CODE to be appended immediately following the AES data stream.
+		/// </summary>
+		protected byte[] AESAuthCode;
+
+		/// <summary>
+		/// Get/set the password used for encryption.
+		/// </summary>
+		/// <remarks>When set to null or if the password is empty no encryption is performed</remarks>
+		public string Password
+		{
+			get
+			{
+				return password;
+			}
+			set
+			{
+				if ((value != null) && (value.Length == 0))
+				{
+					password = null;
+				}
+				else
+				{
+					password = value;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Encrypt a block of data
+		/// </summary>
+		/// <param name="buffer">
+		/// Data to encrypt.  NOTE the original contents of the buffer are lost
+		/// </param>
+		/// <param name="offset">
+		/// Offset of first byte in buffer to encrypt
+		/// </param>
+		/// <param name="length">
+		/// Number of bytes in buffer to encrypt
+		/// </param>
+		protected void EncryptBlock(byte[] buffer, int offset, int length)
+		{
+			cryptoTransform_.TransformBlock(buffer, 0, length, buffer, 0);
+		}
+
+		/// <summary>
+		/// Initializes encryption keys based on given <paramref name="password"/>.
+		/// </summary>
+		/// <param name="password">The password.</param>
+		protected void InitializePassword(string password)
+		{
+			var pkManaged = new PkzipClassicManaged();
+			byte[] key = PkzipClassic.GenerateKeys(ZipStrings.ConvertToArray(password));
+			cryptoTransform_ = pkManaged.CreateEncryptor(key, null);
+		}
+
+		/// <summary>
+		/// Initializes encryption keys based on given password.
+		/// </summary>
+		protected void InitializeAESPassword(ZipEntry entry, string rawPassword,
+											out byte[] salt, out byte[] pwdVerifier)
+		{
+			salt = new byte[entry.AESSaltLen];
+			// Salt needs to be cryptographically random, and unique per file
+			if (_aesRnd == null)
+				_aesRnd = RandomNumberGenerator.Create();
+			_aesRnd.GetBytes(salt);
+			int blockSize = entry.AESKeySize / 8;   // bits to bytes
+
+			cryptoTransform_ = new ZipAESTransform(rawPassword, salt, blockSize, true);
+			pwdVerifier = ((ZipAESTransform)cryptoTransform_).PwdVerifier;
+		}
+
+		#endregion Encryption
+
+		#region Deflation Support
+
+		/// <summary>
+		/// Deflates everything in the input buffers.  This will call
+		/// <code>def.deflate()</code> until all bytes from the input buffers
+		/// are processed.
+		/// </summary>
+		protected void Deflate()
+		{
+			while (!deflater_.IsNeedingInput)
+			{
+				int deflateCount = deflater_.Deflate(buffer_, 0, buffer_.Length);
+
+				if (deflateCount <= 0)
+				{
+					break;
+				}
+				if (cryptoTransform_ != null)
+				{
+					EncryptBlock(buffer_, 0, deflateCount);
+				}
+
+				baseOutputStream_.Write(buffer_, 0, deflateCount);
+			}
+
+			if (!deflater_.IsNeedingInput)
+			{
+				throw new SharpZipBaseException("DeflaterOutputStream can't deflate all input?");
+			}
+		}
+
+		#endregion Deflation Support
+
+		#region Stream Overrides
+
+		/// <summary>
+		/// Gets value indicating stream can be read from
+		/// </summary>
+		public override bool CanRead
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating if seeking is supported for this stream
+		/// This property always returns false
+		/// </summary>
+		public override bool CanSeek
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// Get value indicating if this stream supports writing
+		/// </summary>
+		public override bool CanWrite
+		{
+			get
+			{
+				return baseOutputStream_.CanWrite;
+			}
+		}
+
+		/// <summary>
+		/// Get current length of stream
+		/// </summary>
+		public override long Length
+		{
+			get
+			{
+				return baseOutputStream_.Length;
+			}
+		}
+
+		/// <summary>
+		/// Gets the current position within the stream.
+		/// </summary>
+		/// <exception cref="NotSupportedException">Any attempt to set position</exception>
+		public override long Position
+		{
+			get
+			{
+				return baseOutputStream_.Position;
+			}
+			set
+			{
+				throw new NotSupportedException("Position property not supported");
+			}
+		}
+
+		/// <summary>
+		/// Sets the current position of this stream to the given value. Not supported by this class!
+		/// </summary>
+		/// <param name="offset">The offset relative to the <paramref name="origin"/> to seek.</param>
+		/// <param name="origin">The <see cref="SeekOrigin"/> to seek from.</param>
+		/// <returns>The new position in the stream.</returns>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override long Seek(long offset, SeekOrigin origin)
+		{
+			throw new NotSupportedException("DeflaterOutputStream Seek not supported");
+		}
+
+		/// <summary>
+		/// Sets the length of this stream to the given value. Not supported by this class!
+		/// </summary>
+		/// <param name="value">The new stream length.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void SetLength(long value)
+		{
+			throw new NotSupportedException("DeflaterOutputStream SetLength not supported");
+		}
+
+		/// <summary>
+		/// Read a byte from stream advancing position by one
+		/// </summary>
+		/// <returns>The byte read cast to an int.  THe value is -1 if at the end of the stream.</returns>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override int ReadByte()
+		{
+			throw new NotSupportedException("DeflaterOutputStream ReadByte not supported");
+		}
+
+		/// <summary>
+		/// Read a block of bytes from stream
+		/// </summary>
+		/// <param name="buffer">The buffer to store read data in.</param>
+		/// <param name="offset">The offset to start storing at.</param>
+		/// <param name="count">The maximum number of bytes to read.</param>
+		/// <returns>The actual number of bytes read.  Zero if end of stream is detected.</returns>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			throw new NotSupportedException("DeflaterOutputStream Read not supported");
+		}
+
+		/// <summary>
+		/// Flushes the stream by calling <see cref="DeflaterOutputStream.Flush">Flush</see> on the deflater and then
+		/// on the underlying stream.  This ensures that all bytes are flushed.
+		/// </summary>
+		public override void Flush()
+		{
+			deflater_.Flush();
+			Deflate();
+			baseOutputStream_.Flush();
+		}
+
+		/// <summary>
+		/// Calls <see cref="Finish"/> and closes the underlying
+		/// stream when <see cref="IsStreamOwner"></see> is true.
+		/// </summary>
+		protected override void Dispose(bool disposing)
+		{
+			if (!isClosed_)
+			{
+				isClosed_ = true;
+
+				try
+				{
+					Finish();
+					if (cryptoTransform_ != null)
+					{
+						GetAuthCodeIfAES();
+						cryptoTransform_.Dispose();
+						cryptoTransform_ = null;
+					}
+				}
+				finally
+				{
+					if (IsStreamOwner)
+					{
+						baseOutputStream_.Dispose();
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// Get the Auth code for AES encrypted entries
+		/// </summary>
+		protected void GetAuthCodeIfAES()
+		{
+			if (cryptoTransform_ is ZipAESTransform)
+			{
+				AESAuthCode = ((ZipAESTransform)cryptoTransform_).GetAuthCode();
+			}
+		}
+
+		/// <summary>
+		/// Writes a single byte to the compressed output stream.
+		/// </summary>
+		/// <param name="value">
+		/// The byte value.
+		/// </param>
+		public override void WriteByte(byte value)
+		{
+			byte[] b = new byte[1];
+			b[0] = value;
+			Write(b, 0, 1);
+		}
+
+		/// <summary>
+		/// Writes bytes from an array to the compressed stream.
+		/// </summary>
+		/// <param name="buffer">
+		/// The byte array
+		/// </param>
+		/// <param name="offset">
+		/// The offset into the byte array where to start.
+		/// </param>
+		/// <param name="count">
+		/// The number of bytes to write.
+		/// </param>
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			deflater_.SetInput(buffer, offset, count);
+			Deflate();
+		}
+
+		#endregion Stream Overrides
+
+		#region Instance Fields
+
+		/// <summary>
+		/// This buffer is used temporarily to retrieve the bytes from the
+		/// deflater and write them to the underlying output stream.
+		/// </summary>
+		private byte[] buffer_;
+
+		/// <summary>
+		/// The deflater which is used to deflate the stream.
+		/// </summary>
+		protected Deflater deflater_;
+
+		/// <summary>
+		/// Base stream the deflater depends on.
+		/// </summary>
+		protected Stream baseOutputStream_;
+
+		private bool isClosed_;
+
+		#endregion Instance Fields
+
+		#region Static Fields
+
+		// Static to help ensure that multiple files within a zip will get different random salt
+		private static RandomNumberGenerator _aesRnd = RandomNumberGenerator.Create();
+
+		#endregion Static Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/Streams/InflaterInputStream.cs

@@ -0,0 +1,713 @@
+using System;
+using System.IO;
+using System.Security.Cryptography;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression.Streams
+{
+	/// <summary>
+	/// An input buffer customised for use by <see cref="InflaterInputStream"/>
+	/// </summary>
+	/// <remarks>
+	/// The buffer supports decryption of incoming data.
+	/// </remarks>
+	public class InflaterInputBuffer
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="InflaterInputBuffer"/> with a default buffer size
+		/// </summary>
+		/// <param name="stream">The stream to buffer.</param>
+		public InflaterInputBuffer(Stream stream) : this(stream, 4096)
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="InflaterInputBuffer"/>
+		/// </summary>
+		/// <param name="stream">The stream to buffer.</param>
+		/// <param name="bufferSize">The size to use for the buffer</param>
+		/// <remarks>A minimum buffer size of 1KB is permitted.  Lower sizes are treated as 1KB.</remarks>
+		public InflaterInputBuffer(Stream stream, int bufferSize)
+		{
+			inputStream = stream;
+			if (bufferSize < 1024)
+			{
+				bufferSize = 1024;
+			}
+			rawData = new byte[bufferSize];
+			clearText = rawData;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Get the length of bytes bytes in the <see cref="RawData"/>
+		/// </summary>
+		public int RawLength
+		{
+			get
+			{
+				return rawLength;
+			}
+		}
+
+		/// <summary>
+		/// Get the contents of the raw data buffer.
+		/// </summary>
+		/// <remarks>This may contain encrypted data.</remarks>
+		public byte[] RawData
+		{
+			get
+			{
+				return rawData;
+			}
+		}
+
+		/// <summary>
+		/// Get the number of useable bytes in <see cref="ClearText"/>
+		/// </summary>
+		public int ClearTextLength
+		{
+			get
+			{
+				return clearTextLength;
+			}
+		}
+
+		/// <summary>
+		/// Get the contents of the clear text buffer.
+		/// </summary>
+		public byte[] ClearText
+		{
+			get
+			{
+				return clearText;
+			}
+		}
+
+		/// <summary>
+		/// Get/set the number of bytes available
+		/// </summary>
+		public int Available
+		{
+			get { return available; }
+			set { available = value; }
+		}
+
+		/// <summary>
+		/// Call <see cref="Inflater.SetInput(byte[], int, int)"/> passing the current clear text buffer contents.
+		/// </summary>
+		/// <param name="inflater">The inflater to set input for.</param>
+		public void SetInflaterInput(Inflater inflater)
+		{
+			if (available > 0)
+			{
+				inflater.SetInput(clearText, clearTextLength - available, available);
+				available = 0;
+			}
+		}
+
+		/// <summary>
+		/// Fill the buffer from the underlying input stream.
+		/// </summary>
+		public void Fill()
+		{
+			rawLength = 0;
+			int toRead = rawData.Length;
+
+			while (toRead > 0)
+			{
+				int count = inputStream.Read(rawData, rawLength, toRead);
+				if (count <= 0)
+				{
+					break;
+				}
+				rawLength += count;
+				toRead -= count;
+			}
+
+			if (cryptoTransform != null)
+			{
+				clearTextLength = cryptoTransform.TransformBlock(rawData, 0, rawLength, clearText, 0);
+			}
+			else
+			{
+				clearTextLength = rawLength;
+			}
+
+			available = clearTextLength;
+		}
+
+		/// <summary>
+		/// Read a buffer directly from the input stream
+		/// </summary>
+		/// <param name="buffer">The buffer to fill</param>
+		/// <returns>Returns the number of bytes read.</returns>
+		public int ReadRawBuffer(byte[] buffer)
+		{
+			return ReadRawBuffer(buffer, 0, buffer.Length);
+		}
+
+		/// <summary>
+		/// Read a buffer directly from the input stream
+		/// </summary>
+		/// <param name="outBuffer">The buffer to read into</param>
+		/// <param name="offset">The offset to start reading data into.</param>
+		/// <param name="length">The number of bytes to read.</param>
+		/// <returns>Returns the number of bytes read.</returns>
+		public int ReadRawBuffer(byte[] outBuffer, int offset, int length)
+		{
+			if (length < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(length));
+			}
+
+			int currentOffset = offset;
+			int currentLength = length;
+
+			while (currentLength > 0)
+			{
+				if (available <= 0)
+				{
+					Fill();
+					if (available <= 0)
+					{
+						return 0;
+					}
+				}
+				int toCopy = Math.Min(currentLength, available);
+				System.Array.Copy(rawData, rawLength - (int)available, outBuffer, currentOffset, toCopy);
+				currentOffset += toCopy;
+				currentLength -= toCopy;
+				available -= toCopy;
+			}
+			return length;
+		}
+
+		/// <summary>
+		/// Read clear text data from the input stream.
+		/// </summary>
+		/// <param name="outBuffer">The buffer to add data to.</param>
+		/// <param name="offset">The offset to start adding data at.</param>
+		/// <param name="length">The number of bytes to read.</param>
+		/// <returns>Returns the number of bytes actually read.</returns>
+		public int ReadClearTextBuffer(byte[] outBuffer, int offset, int length)
+		{
+			if (length < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(length));
+			}
+
+			int currentOffset = offset;
+			int currentLength = length;
+
+			while (currentLength > 0)
+			{
+				if (available <= 0)
+				{
+					Fill();
+					if (available <= 0)
+					{
+						return 0;
+					}
+				}
+
+				int toCopy = Math.Min(currentLength, available);
+				Array.Copy(clearText, clearTextLength - (int)available, outBuffer, currentOffset, toCopy);
+				currentOffset += toCopy;
+				currentLength -= toCopy;
+				available -= toCopy;
+			}
+			return length;
+		}
+
+		/// <summary>
+		/// Read a <see cref="byte"/> from the input stream.
+		/// </summary>
+		/// <returns>Returns the byte read.</returns>
+		public int ReadLeByte()
+		{
+			if (available <= 0)
+			{
+				Fill();
+				if (available <= 0)
+				{
+					throw new ZipException("EOF in header");
+				}
+			}
+			byte result = rawData[rawLength - available];
+			available -= 1;
+			return result;
+		}
+
+		/// <summary>
+		/// Read an <see cref="short"/> in little endian byte order.
+		/// </summary>
+		/// <returns>The short value read case to an int.</returns>
+		public int ReadLeShort()
+		{
+			return ReadLeByte() | (ReadLeByte() << 8);
+		}
+
+		/// <summary>
+		/// Read an <see cref="int"/> in little endian byte order.
+		/// </summary>
+		/// <returns>The int value read.</returns>
+		public int ReadLeInt()
+		{
+			return ReadLeShort() | (ReadLeShort() << 16);
+		}
+
+		/// <summary>
+		/// Read a <see cref="long"/> in little endian byte order.
+		/// </summary>
+		/// <returns>The long value read.</returns>
+		public long ReadLeLong()
+		{
+			return (uint)ReadLeInt() | ((long)ReadLeInt() << 32);
+		}
+
+		/// <summary>
+		/// Get/set the <see cref="ICryptoTransform"/> to apply to any data.
+		/// </summary>
+		/// <remarks>Set this value to null to have no transform applied.</remarks>
+		public ICryptoTransform CryptoTransform
+		{
+			set
+			{
+				cryptoTransform = value;
+				if (cryptoTransform != null)
+				{
+					if (rawData == clearText)
+					{
+						if (internalClearText == null)
+						{
+							internalClearText = new byte[rawData.Length];
+						}
+						clearText = internalClearText;
+					}
+					clearTextLength = rawLength;
+					if (available > 0)
+					{
+						cryptoTransform.TransformBlock(rawData, rawLength - available, available, clearText, rawLength - available);
+					}
+				}
+				else
+				{
+					clearText = rawData;
+					clearTextLength = rawLength;
+				}
+			}
+		}
+
+		#region Instance Fields
+
+		private int rawLength;
+		private byte[] rawData;
+
+		private int clearTextLength;
+		private byte[] clearText;
+		private byte[] internalClearText;
+
+		private int available;
+
+		private ICryptoTransform cryptoTransform;
+		private Stream inputStream;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// This filter stream is used to decompress data compressed using the "deflate"
+	/// format. The "deflate" format is described in RFC 1951.
+	///
+	/// This stream may form the basis for other decompression filters, such
+	/// as the <see cref="ICSharpCode.SharpZipLib.GZip.GZipInputStream">GZipInputStream</see>.
+	///
+	/// Author of the original java version : John Leuner.
+	/// </summary>
+	public class InflaterInputStream : Stream
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Create an InflaterInputStream with the default decompressor
+		/// and a default buffer size of 4KB.
+		/// </summary>
+		/// <param name = "baseInputStream">
+		/// The InputStream to read bytes from
+		/// </param>
+		public InflaterInputStream(Stream baseInputStream)
+			: this(baseInputStream, new Inflater(), 4096)
+		{
+		}
+
+		/// <summary>
+		/// Create an InflaterInputStream with the specified decompressor
+		/// and a default buffer size of 4KB.
+		/// </summary>
+		/// <param name = "baseInputStream">
+		/// The source of input data
+		/// </param>
+		/// <param name = "inf">
+		/// The decompressor used to decompress data read from baseInputStream
+		/// </param>
+		public InflaterInputStream(Stream baseInputStream, Inflater inf)
+			: this(baseInputStream, inf, 4096)
+		{
+		}
+
+		/// <summary>
+		/// Create an InflaterInputStream with the specified decompressor
+		/// and the specified buffer size.
+		/// </summary>
+		/// <param name = "baseInputStream">
+		/// The InputStream to read bytes from
+		/// </param>
+		/// <param name = "inflater">
+		/// The decompressor to use
+		/// </param>
+		/// <param name = "bufferSize">
+		/// Size of the buffer to use
+		/// </param>
+		public InflaterInputStream(Stream baseInputStream, Inflater inflater, int bufferSize)
+		{
+			if (baseInputStream == null)
+			{
+				throw new ArgumentNullException(nameof(baseInputStream));
+			}
+
+			if (inflater == null)
+			{
+				throw new ArgumentNullException(nameof(inflater));
+			}
+
+			if (bufferSize <= 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(bufferSize));
+			}
+
+			this.baseInputStream = baseInputStream;
+			this.inf = inflater;
+
+			inputBuffer = new InflaterInputBuffer(baseInputStream, bufferSize);
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Gets or sets a flag indicating ownership of underlying stream.
+		/// When the flag is true <see cref="Stream.Dispose()" /> will close the underlying stream also.
+		/// </summary>
+		/// <remarks>The default value is true.</remarks>
+		public bool IsStreamOwner { get; set; } = true;
+
+		/// <summary>
+		/// Skip specified number of bytes of uncompressed data
+		/// </summary>
+		/// <param name ="count">
+		/// Number of bytes to skip
+		/// </param>
+		/// <returns>
+		/// The number of bytes skipped, zero if the end of
+		/// stream has been reached
+		/// </returns>
+		/// <exception cref="ArgumentOutOfRangeException">
+		/// <paramref name="count">The number of bytes</paramref> to skip is less than or equal to zero.
+		/// </exception>
+		public long Skip(long count)
+		{
+			if (count <= 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(count));
+			}
+
+			// v0.80 Skip by seeking if underlying stream supports it...
+			if (baseInputStream.CanSeek)
+			{
+				baseInputStream.Seek(count, SeekOrigin.Current);
+				return count;
+			}
+			else
+			{
+				int length = 2048;
+				if (count < length)
+				{
+					length = (int)count;
+				}
+
+				byte[] tmp = new byte[length];
+				int readCount = 1;
+				long toSkip = count;
+
+				while ((toSkip > 0) && (readCount > 0))
+				{
+					if (toSkip < length)
+					{
+						length = (int)toSkip;
+					}
+
+					readCount = baseInputStream.Read(tmp, 0, length);
+					toSkip -= readCount;
+				}
+
+				return count - toSkip;
+			}
+		}
+
+		/// <summary>
+		/// Clear any cryptographic state.
+		/// </summary>
+		protected void StopDecrypting()
+		{
+			inputBuffer.CryptoTransform = null;
+		}
+
+		/// <summary>
+		/// Returns 0 once the end of the stream (EOF) has been reached.
+		/// Otherwise returns 1.
+		/// </summary>
+		public virtual int Available
+		{
+			get
+			{
+				return inf.IsFinished ? 0 : 1;
+			}
+		}
+
+		/// <summary>
+		/// Fills the buffer with more data to decompress.
+		/// </summary>
+		/// <exception cref="SharpZipBaseException">
+		/// Stream ends early
+		/// </exception>
+		protected void Fill()
+		{
+			// Protect against redundant calls
+			if (inputBuffer.Available <= 0)
+			{
+				inputBuffer.Fill();
+				if (inputBuffer.Available <= 0)
+				{
+					throw new SharpZipBaseException("Unexpected EOF");
+				}
+			}
+			inputBuffer.SetInflaterInput(inf);
+		}
+
+		#region Stream Overrides
+
+		/// <summary>
+		/// Gets a value indicating whether the current stream supports reading
+		/// </summary>
+		public override bool CanRead
+		{
+			get
+			{
+				return baseInputStream.CanRead;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value of false indicating seeking is not supported for this stream.
+		/// </summary>
+		public override bool CanSeek
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value of false indicating that this stream is not writeable.
+		/// </summary>
+		public override bool CanWrite
+		{
+			get
+			{
+				return false;
+			}
+		}
+
+		/// <summary>
+		/// A value representing the length of the stream in bytes.
+		/// </summary>
+		public override long Length
+		{
+			get
+			{
+				//return inputBuffer.RawLength;
+				throw new NotSupportedException("InflaterInputStream Length is not supported");
+			}
+		}
+
+		/// <summary>
+		/// The current position within the stream.
+		/// Throws a NotSupportedException when attempting to set the position
+		/// </summary>
+		/// <exception cref="NotSupportedException">Attempting to set the position</exception>
+		public override long Position
+		{
+			get
+			{
+				return baseInputStream.Position;
+			}
+			set
+			{
+				throw new NotSupportedException("InflaterInputStream Position not supported");
+			}
+		}
+
+		/// <summary>
+		/// Flushes the baseInputStream
+		/// </summary>
+		public override void Flush()
+		{
+			baseInputStream.Flush();
+		}
+
+		/// <summary>
+		/// Sets the position within the current stream
+		/// Always throws a NotSupportedException
+		/// </summary>
+		/// <param name="offset">The relative offset to seek to.</param>
+		/// <param name="origin">The <see cref="SeekOrigin"/> defining where to seek from.</param>
+		/// <returns>The new position in the stream.</returns>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override long Seek(long offset, SeekOrigin origin)
+		{
+			throw new NotSupportedException("Seek not supported");
+		}
+
+		/// <summary>
+		/// Set the length of the current stream
+		/// Always throws a NotSupportedException
+		/// </summary>
+		/// <param name="value">The new length value for the stream.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void SetLength(long value)
+		{
+			throw new NotSupportedException("InflaterInputStream SetLength not supported");
+		}
+
+		/// <summary>
+		/// Writes a sequence of bytes to stream and advances the current position
+		/// This method always throws a NotSupportedException
+		/// </summary>
+		/// <param name="buffer">Thew buffer containing data to write.</param>
+		/// <param name="offset">The offset of the first byte to write.</param>
+		/// <param name="count">The number of bytes to write.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			throw new NotSupportedException("InflaterInputStream Write not supported");
+		}
+
+		/// <summary>
+		/// Writes one byte to the current stream and advances the current position
+		/// Always throws a NotSupportedException
+		/// </summary>
+		/// <param name="value">The byte to write.</param>
+		/// <exception cref="NotSupportedException">Any access</exception>
+		public override void WriteByte(byte value)
+		{
+			throw new NotSupportedException("InflaterInputStream WriteByte not supported");
+		}
+
+		/// <summary>
+		/// Closes the input stream.  When <see cref="IsStreamOwner"></see>
+		/// is true the underlying stream is also closed.
+		/// </summary>
+		protected override void Dispose(bool disposing)
+		{
+			if (!isClosed)
+			{
+				isClosed = true;
+				if (IsStreamOwner)
+				{
+					baseInputStream.Dispose();
+				}
+			}
+		}
+
+		/// <summary>
+		/// Reads decompressed data into the provided buffer byte array
+		/// </summary>
+		/// <param name ="buffer">
+		/// The array to read and decompress data into
+		/// </param>
+		/// <param name ="offset">
+		/// The offset indicating where the data should be placed
+		/// </param>
+		/// <param name ="count">
+		/// The number of bytes to decompress
+		/// </param>
+		/// <returns>The number of bytes read.  Zero signals the end of stream</returns>
+		/// <exception cref="SharpZipBaseException">
+		/// Inflater needs a dictionary
+		/// </exception>
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			if (inf.IsNeedingDictionary)
+			{
+				throw new SharpZipBaseException("Need a dictionary");
+			}
+
+			int remainingBytes = count;
+			while (true)
+			{
+				int bytesRead = inf.Inflate(buffer, offset, remainingBytes);
+				offset += bytesRead;
+				remainingBytes -= bytesRead;
+
+				if (remainingBytes == 0 || inf.IsFinished)
+				{
+					break;
+				}
+
+				if (inf.IsNeedingInput)
+				{
+					Fill();
+				}
+				else if (bytesRead == 0)
+				{
+					throw new ZipException("Invalid input data");
+				}
+			}
+			return count - remainingBytes;
+		}
+
+		#endregion Stream Overrides
+
+		#region Instance Fields
+
+		/// <summary>
+		/// Decompressor for this stream
+		/// </summary>
+		protected Inflater inf;
+
+		/// <summary>
+		/// <see cref="InflaterInputBuffer">Input buffer</see> for this stream.
+		/// </summary>
+		protected InflaterInputBuffer inputBuffer;
+
+		/// <summary>
+		/// Base stream the inflater reads from.
+		/// </summary>
+		private Stream baseInputStream;
+
+		/// <summary>
+		/// The compressed size
+		/// </summary>
+		protected long csize;
+
+		/// <summary>
+		/// Flag indicating wether this instance has been closed or not.
+		/// </summary>
+		private bool isClosed;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/Streams/OutputWindow.cs

@@ -0,0 +1,220 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression.Streams
+{
+	/// <summary>
+	/// Contains the output from the Inflation process.
+	/// We need to have a window so that we can refer backwards into the output stream
+	/// to repeat stuff.<br/>
+	/// Author of the original java version : John Leuner
+	/// </summary>
+	public class OutputWindow
+	{
+		#region Constants
+
+		private const int WindowSize = 1 << 15;
+		private const int WindowMask = WindowSize - 1;
+
+		#endregion Constants
+
+		#region Instance Fields
+
+		private byte[] window = new byte[WindowSize]; //The window is 2^15 bytes
+		private int windowEnd;
+		private int windowFilled;
+
+		#endregion Instance Fields
+
+		/// <summary>
+		/// Write a byte to this output window
+		/// </summary>
+		/// <param name="value">value to write</param>
+		/// <exception cref="InvalidOperationException">
+		/// if window is full
+		/// </exception>
+		public void Write(int value)
+		{
+			if (windowFilled++ == WindowSize)
+			{
+				throw new InvalidOperationException("Window full");
+			}
+			window[windowEnd++] = (byte)value;
+			windowEnd &= WindowMask;
+		}
+
+		private void SlowRepeat(int repStart, int length, int distance)
+		{
+			while (length-- > 0)
+			{
+				window[windowEnd++] = window[repStart++];
+				windowEnd &= WindowMask;
+				repStart &= WindowMask;
+			}
+		}
+
+		/// <summary>
+		/// Append a byte pattern already in the window itself
+		/// </summary>
+		/// <param name="length">length of pattern to copy</param>
+		/// <param name="distance">distance from end of window pattern occurs</param>
+		/// <exception cref="InvalidOperationException">
+		/// If the repeated data overflows the window
+		/// </exception>
+		public void Repeat(int length, int distance)
+		{
+			if ((windowFilled += length) > WindowSize)
+			{
+				throw new InvalidOperationException("Window full");
+			}
+
+			int repStart = (windowEnd - distance) & WindowMask;
+			int border = WindowSize - length;
+			if ((repStart <= border) && (windowEnd < border))
+			{
+				if (length <= distance)
+				{
+					System.Array.Copy(window, repStart, window, windowEnd, length);
+					windowEnd += length;
+				}
+				else
+				{
+					// We have to copy manually, since the repeat pattern overlaps.
+					while (length-- > 0)
+					{
+						window[windowEnd++] = window[repStart++];
+					}
+				}
+			}
+			else
+			{
+				SlowRepeat(repStart, length, distance);
+			}
+		}
+
+		/// <summary>
+		/// Copy from input manipulator to internal window
+		/// </summary>
+		/// <param name="input">source of data</param>
+		/// <param name="length">length of data to copy</param>
+		/// <returns>the number of bytes copied</returns>
+		public int CopyStored(StreamManipulator input, int length)
+		{
+			length = Math.Min(Math.Min(length, WindowSize - windowFilled), input.AvailableBytes);
+			int copied;
+
+			int tailLen = WindowSize - windowEnd;
+			if (length > tailLen)
+			{
+				copied = input.CopyBytes(window, windowEnd, tailLen);
+				if (copied == tailLen)
+				{
+					copied += input.CopyBytes(window, 0, length - tailLen);
+				}
+			}
+			else
+			{
+				copied = input.CopyBytes(window, windowEnd, length);
+			}
+
+			windowEnd = (windowEnd + copied) & WindowMask;
+			windowFilled += copied;
+			return copied;
+		}
+
+		/// <summary>
+		/// Copy dictionary to window
+		/// </summary>
+		/// <param name="dictionary">source dictionary</param>
+		/// <param name="offset">offset of start in source dictionary</param>
+		/// <param name="length">length of dictionary</param>
+		/// <exception cref="InvalidOperationException">
+		/// If window isnt empty
+		/// </exception>
+		public void CopyDict(byte[] dictionary, int offset, int length)
+		{
+			if (dictionary == null)
+			{
+				throw new ArgumentNullException(nameof(dictionary));
+			}
+
+			if (windowFilled > 0)
+			{
+				throw new InvalidOperationException();
+			}
+
+			if (length > WindowSize)
+			{
+				offset += length - WindowSize;
+				length = WindowSize;
+			}
+			System.Array.Copy(dictionary, offset, window, 0, length);
+			windowEnd = length & WindowMask;
+		}
+
+		/// <summary>
+		/// Get remaining unfilled space in window
+		/// </summary>
+		/// <returns>Number of bytes left in window</returns>
+		public int GetFreeSpace()
+		{
+			return WindowSize - windowFilled;
+		}
+
+		/// <summary>
+		/// Get bytes available for output in window
+		/// </summary>
+		/// <returns>Number of bytes filled</returns>
+		public int GetAvailable()
+		{
+			return windowFilled;
+		}
+
+		/// <summary>
+		/// Copy contents of window to output
+		/// </summary>
+		/// <param name="output">buffer to copy to</param>
+		/// <param name="offset">offset to start at</param>
+		/// <param name="len">number of bytes to count</param>
+		/// <returns>The number of bytes copied</returns>
+		/// <exception cref="InvalidOperationException">
+		/// If a window underflow occurs
+		/// </exception>
+		public int CopyOutput(byte[] output, int offset, int len)
+		{
+			int copyEnd = windowEnd;
+			if (len > windowFilled)
+			{
+				len = windowFilled;
+			}
+			else
+			{
+				copyEnd = (windowEnd - windowFilled + len) & WindowMask;
+			}
+
+			int copied = len;
+			int tailLen = len - copyEnd;
+
+			if (tailLen > 0)
+			{
+				System.Array.Copy(window, WindowSize - tailLen, output, offset, tailLen);
+				offset += tailLen;
+				len = copyEnd;
+			}
+			System.Array.Copy(window, copyEnd - len, output, offset, len);
+			windowFilled -= copied;
+			if (windowFilled < 0)
+			{
+				throw new InvalidOperationException();
+			}
+			return copied;
+		}
+
+		/// <summary>
+		/// Reset by clearing window so <see cref="GetAvailable">GetAvailable</see> returns 0
+		/// </summary>
+		public void Reset()
+		{
+			windowFilled = windowEnd = 0;
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/Compression/Streams/StreamManipulator.cs

@@ -0,0 +1,298 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip.Compression.Streams
+{
+	/// <summary>
+	/// This class allows us to retrieve a specified number of bits from
+	/// the input buffer, as well as copy big byte blocks.
+	///
+	/// It uses an int buffer to store up to 31 bits for direct
+	/// manipulation.  This guarantees that we can get at least 16 bits,
+	/// but we only need at most 15, so this is all safe.
+	///
+	/// There are some optimizations in this class, for example, you must
+	/// never peek more than 8 bits more than needed, and you must first
+	/// peek bits before you may drop them.  This is not a general purpose
+	/// class but optimized for the behaviour of the Inflater.
+	///
+	/// authors of the original java version : John Leuner, Jochen Hoenicke
+	/// </summary>
+	public class StreamManipulator
+	{
+		/// <summary>
+		/// Get the next sequence of bits but don't increase input pointer.  bitCount must be
+		/// less or equal 16 and if this call succeeds, you must drop
+		/// at least n - 8 bits in the next call.
+		/// </summary>
+		/// <param name="bitCount">The number of bits to peek.</param>
+		/// <returns>
+		/// the value of the bits, or -1 if not enough bits available.  */
+		/// </returns>
+		public int PeekBits(int bitCount)
+		{
+			if (bitsInBuffer_ < bitCount)
+			{
+				if (windowStart_ == windowEnd_)
+				{
+					return -1; // ok
+				}
+				buffer_ |= (uint)((window_[windowStart_++] & 0xff |
+								 (window_[windowStart_++] & 0xff) << 8) << bitsInBuffer_);
+				bitsInBuffer_ += 16;
+			}
+			return (int)(buffer_ & ((1 << bitCount) - 1));
+		}
+
+		/// <summary>
+		/// Tries to grab the next <paramref name="bitCount"/> bits from the input and
+		/// sets <paramref name="output"/> to the value, adding <paramref name="outputOffset"/>.
+		/// </summary>
+		/// <returns>true if enough bits could be read, otherwise false</returns>
+		public bool TryGetBits(int bitCount, ref int output, int outputOffset = 0)
+		{
+			var bits = PeekBits(bitCount);
+			if (bits < 0)
+			{
+				return false;
+			}
+			output = bits + outputOffset;
+			DropBits(bitCount);
+			return true;
+		}
+
+		/// <summary>
+		/// Tries to grab the next <paramref name="bitCount"/> bits from the input and
+		/// sets <paramref name="index"/> of <paramref name="array"/> to the value.
+		/// </summary>
+		/// <returns>true if enough bits could be read, otherwise false</returns>
+		public bool TryGetBits(int bitCount, ref byte[] array, int index)
+		{
+			var bits = PeekBits(bitCount);
+			if (bits < 0)
+			{
+				return false;
+			}
+			array[index] = (byte)bits;
+			DropBits(bitCount);
+			return true;
+		}
+
+		/// <summary>
+		/// Drops the next n bits from the input.  You should have called PeekBits
+		/// with a bigger or equal n before, to make sure that enough bits are in
+		/// the bit buffer.
+		/// </summary>
+		/// <param name="bitCount">The number of bits to drop.</param>
+		public void DropBits(int bitCount)
+		{
+			buffer_ >>= bitCount;
+			bitsInBuffer_ -= bitCount;
+		}
+
+		/// <summary>
+		/// Gets the next n bits and increases input pointer.  This is equivalent
+		/// to <see cref="PeekBits"/> followed by <see cref="DropBits"/>, except for correct error handling.
+		/// </summary>
+		/// <param name="bitCount">The number of bits to retrieve.</param>
+		/// <returns>
+		/// the value of the bits, or -1 if not enough bits available.
+		/// </returns>
+		public int GetBits(int bitCount)
+		{
+			int bits = PeekBits(bitCount);
+			if (bits >= 0)
+			{
+				DropBits(bitCount);
+			}
+			return bits;
+		}
+
+		/// <summary>
+		/// Gets the number of bits available in the bit buffer.  This must be
+		/// only called when a previous PeekBits() returned -1.
+		/// </summary>
+		/// <returns>
+		/// the number of bits available.
+		/// </returns>
+		public int AvailableBits
+		{
+			get
+			{
+				return bitsInBuffer_;
+			}
+		}
+
+		/// <summary>
+		/// Gets the number of bytes available.
+		/// </summary>
+		/// <returns>
+		/// The number of bytes available.
+		/// </returns>
+		public int AvailableBytes
+		{
+			get
+			{
+				return windowEnd_ - windowStart_ + (bitsInBuffer_ >> 3);
+			}
+		}
+
+		/// <summary>
+		/// Skips to the next byte boundary.
+		/// </summary>
+		public void SkipToByteBoundary()
+		{
+			buffer_ >>= (bitsInBuffer_ & 7);
+			bitsInBuffer_ &= ~7;
+		}
+
+		/// <summary>
+		/// Returns true when SetInput can be called
+		/// </summary>
+		public bool IsNeedingInput
+		{
+			get
+			{
+				return windowStart_ == windowEnd_;
+			}
+		}
+
+		/// <summary>
+		/// Copies bytes from input buffer to output buffer starting
+		/// at output[offset].  You have to make sure, that the buffer is
+		/// byte aligned.  If not enough bytes are available, copies fewer
+		/// bytes.
+		/// </summary>
+		/// <param name="output">
+		/// The buffer to copy bytes to.
+		/// </param>
+		/// <param name="offset">
+		/// The offset in the buffer at which copying starts
+		/// </param>
+		/// <param name="length">
+		/// The length to copy, 0 is allowed.
+		/// </param>
+		/// <returns>
+		/// The number of bytes copied, 0 if no bytes were available.
+		/// </returns>
+		/// <exception cref="ArgumentOutOfRangeException">
+		/// Length is less than zero
+		/// </exception>
+		/// <exception cref="InvalidOperationException">
+		/// Bit buffer isnt byte aligned
+		/// </exception>
+		public int CopyBytes(byte[] output, int offset, int length)
+		{
+			if (length < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(length));
+			}
+
+			if ((bitsInBuffer_ & 7) != 0)
+			{
+				// bits_in_buffer may only be 0 or a multiple of 8
+				throw new InvalidOperationException("Bit buffer is not byte aligned!");
+			}
+
+			int count = 0;
+			while ((bitsInBuffer_ > 0) && (length > 0))
+			{
+				output[offset++] = (byte)buffer_;
+				buffer_ >>= 8;
+				bitsInBuffer_ -= 8;
+				length--;
+				count++;
+			}
+
+			if (length == 0)
+			{
+				return count;
+			}
+
+			int avail = windowEnd_ - windowStart_;
+			if (length > avail)
+			{
+				length = avail;
+			}
+			System.Array.Copy(window_, windowStart_, output, offset, length);
+			windowStart_ += length;
+
+			if (((windowStart_ - windowEnd_) & 1) != 0)
+			{
+				// We always want an even number of bytes in input, see peekBits
+				buffer_ = (uint)(window_[windowStart_++] & 0xff);
+				bitsInBuffer_ = 8;
+			}
+			return count + length;
+		}
+
+		/// <summary>
+		/// Resets state and empties internal buffers
+		/// </summary>
+		public void Reset()
+		{
+			buffer_ = 0;
+			windowStart_ = windowEnd_ = bitsInBuffer_ = 0;
+		}
+
+		/// <summary>
+		/// Add more input for consumption.
+		/// Only call when IsNeedingInput returns true
+		/// </summary>
+		/// <param name="buffer">data to be input</param>
+		/// <param name="offset">offset of first byte of input</param>
+		/// <param name="count">number of bytes of input to add.</param>
+		public void SetInput(byte[] buffer, int offset, int count)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			if (offset < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset), "Cannot be negative");
+			}
+
+			if (count < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(count), "Cannot be negative");
+			}
+
+			if (windowStart_ < windowEnd_)
+			{
+				throw new InvalidOperationException("Old input was not completely processed");
+			}
+
+			int end = offset + count;
+
+			// We want to throw an ArrayIndexOutOfBoundsException early.
+			// Note the check also handles integer wrap around.
+			if ((offset > end) || (end > buffer.Length))
+			{
+				throw new ArgumentOutOfRangeException(nameof(count));
+			}
+
+			if ((count & 1) != 0)
+			{
+				// We always want an even number of bytes in input, see PeekBits
+				buffer_ |= (uint)((buffer[offset++] & 0xff) << bitsInBuffer_);
+				bitsInBuffer_ += 8;
+			}
+
+			window_ = buffer;
+			windowStart_ = offset;
+			windowEnd_ = end;
+		}
+
+		#region Instance Fields
+
+		private byte[] window_;
+		private int windowStart_;
+		private int windowEnd_;
+
+		private uint buffer_;
+		private int bitsInBuffer_;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/FastZip.cs

@@ -0,0 +1,779 @@
+using ICSharpCode.SharpZipLib.Core;
+using ICSharpCode.SharpZipLib.Zip.Compression;
+using System;
+using System.IO;
+using static ICSharpCode.SharpZipLib.Zip.Compression.Deflater;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// FastZipEvents supports all events applicable to <see cref="FastZip">FastZip</see> operations.
+	/// </summary>
+	public class FastZipEvents
+	{
+		/// <summary>
+		/// Delegate to invoke when processing directories.
+		/// </summary>
+		public event EventHandler<DirectoryEventArgs> ProcessDirectory;
+
+		/// <summary>
+		/// Delegate to invoke when processing files.
+		/// </summary>
+		public ProcessFileHandler ProcessFile;
+
+		/// <summary>
+		/// Delegate to invoke during processing of files.
+		/// </summary>
+		public ProgressHandler Progress;
+
+		/// <summary>
+		/// Delegate to invoke when processing for a file has been completed.
+		/// </summary>
+		public CompletedFileHandler CompletedFile;
+
+		/// <summary>
+		/// Delegate to invoke when processing directory failures.
+		/// </summary>
+		public DirectoryFailureHandler DirectoryFailure;
+
+		/// <summary>
+		/// Delegate to invoke when processing file failures.
+		/// </summary>
+		public FileFailureHandler FileFailure;
+
+		/// <summary>
+		/// Raise the <see cref="DirectoryFailure">directory failure</see> event.
+		/// </summary>
+		/// <param name="directory">The directory causing the failure.</param>
+		/// <param name="e">The exception for this event.</param>
+		/// <returns>A boolean indicating if execution should continue or not.</returns>
+		public bool OnDirectoryFailure(string directory, Exception e)
+		{
+			bool result = false;
+			DirectoryFailureHandler handler = DirectoryFailure;
+
+			if (handler != null)
+			{
+				var args = new ScanFailureEventArgs(directory, e);
+				handler(this, args);
+				result = args.ContinueRunning;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Fires the <see cref="FileFailure"> file failure handler delegate</see>.
+		/// </summary>
+		/// <param name="file">The file causing the failure.</param>
+		/// <param name="e">The exception for this failure.</param>
+		/// <returns>A boolean indicating if execution should continue or not.</returns>
+		public bool OnFileFailure(string file, Exception e)
+		{
+			FileFailureHandler handler = FileFailure;
+			bool result = (handler != null);
+
+			if (result)
+			{
+				var args = new ScanFailureEventArgs(file, e);
+				handler(this, args);
+				result = args.ContinueRunning;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Fires the <see cref="ProcessFile">ProcessFile delegate</see>.
+		/// </summary>
+		/// <param name="file">The file being processed.</param>
+		/// <returns>A boolean indicating if execution should continue or not.</returns>
+		public bool OnProcessFile(string file)
+		{
+			bool result = true;
+			ProcessFileHandler handler = ProcessFile;
+
+			if (handler != null)
+			{
+				var args = new ScanEventArgs(file);
+				handler(this, args);
+				result = args.ContinueRunning;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Fires the <see cref="CompletedFile"/> delegate
+		/// </summary>
+		/// <param name="file">The file whose processing has been completed.</param>
+		/// <returns>A boolean indicating if execution should continue or not.</returns>
+		public bool OnCompletedFile(string file)
+		{
+			bool result = true;
+			CompletedFileHandler handler = CompletedFile;
+			if (handler != null)
+			{
+				var args = new ScanEventArgs(file);
+				handler(this, args);
+				result = args.ContinueRunning;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Fires the <see cref="ProcessDirectory">process directory</see> delegate.
+		/// </summary>
+		/// <param name="directory">The directory being processed.</param>
+		/// <param name="hasMatchingFiles">Flag indicating if the directory has matching files as determined by the current filter.</param>
+		/// <returns>A <see cref="bool"/> of true if the operation should continue; false otherwise.</returns>
+		public bool OnProcessDirectory(string directory, bool hasMatchingFiles)
+		{
+			bool result = true;
+			EventHandler<DirectoryEventArgs> handler = ProcessDirectory;
+			if (handler != null)
+			{
+				var args = new DirectoryEventArgs(directory, hasMatchingFiles);
+				handler(this, args);
+				result = args.ContinueRunning;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// The minimum timespan between <see cref="Progress"/> events.
+		/// </summary>
+		/// <value>The minimum period of time between <see cref="Progress"/> events.</value>
+		/// <seealso cref="Progress"/>
+		/// <remarks>The default interval is three seconds.</remarks>
+		public TimeSpan ProgressInterval
+		{
+			get { return progressInterval_; }
+			set { progressInterval_ = value; }
+		}
+
+		#region Instance Fields
+
+		private TimeSpan progressInterval_ = TimeSpan.FromSeconds(3);
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// FastZip provides facilities for creating and extracting zip files.
+	/// </summary>
+	public class FastZip
+	{
+		#region Enumerations
+
+		/// <summary>
+		/// Defines the desired handling when overwriting files during extraction.
+		/// </summary>
+		public enum Overwrite
+		{
+			/// <summary>
+			/// Prompt the user to confirm overwriting
+			/// </summary>
+			Prompt,
+
+			/// <summary>
+			/// Never overwrite files.
+			/// </summary>
+			Never,
+
+			/// <summary>
+			/// Always overwrite files.
+			/// </summary>
+			Always
+		}
+
+		#endregion Enumerations
+
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a default instance of <see cref="FastZip"/>.
+		/// </summary>
+		public FastZip()
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="FastZip"/>
+		/// </summary>
+		/// <param name="events">The <see cref="FastZipEvents">events</see> to use during operations.</param>
+		public FastZip(FastZipEvents events)
+		{
+			events_ = events;
+		}
+
+		#endregion Constructors
+
+		#region Properties
+
+		/// <summary>
+		/// Get/set a value indicating wether empty directories should be created.
+		/// </summary>
+		public bool CreateEmptyDirectories
+		{
+			get { return createEmptyDirectories_; }
+			set { createEmptyDirectories_ = value; }
+		}
+
+		/// <summary>
+		/// Get / set the password value.
+		/// </summary>
+		public string Password
+		{
+			get { return password_; }
+			set { password_ = value; }
+		}
+
+		/// <summary>
+		/// Get or set the <see cref="INameTransform"></see> active when creating Zip files.
+		/// </summary>
+		/// <seealso cref="EntryFactory"></seealso>
+		public INameTransform NameTransform
+		{
+			get { return entryFactory_.NameTransform; }
+			set
+			{
+				entryFactory_.NameTransform = value;
+			}
+		}
+
+		/// <summary>
+		/// Get or set the <see cref="IEntryFactory"></see> active when creating Zip files.
+		/// </summary>
+		public IEntryFactory EntryFactory
+		{
+			get { return entryFactory_; }
+			set
+			{
+				if (value == null)
+				{
+					entryFactory_ = new ZipEntryFactory();
+				}
+				else
+				{
+					entryFactory_ = value;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Gets or sets the setting for <see cref="UseZip64">Zip64 handling when writing.</see>
+		/// </summary>
+		/// <remarks>
+		/// The default value is dynamic which is not backwards compatible with old
+		/// programs and can cause problems with XP's built in compression which cant
+		/// read Zip64 archives. However it does avoid the situation were a large file
+		/// is added and cannot be completed correctly.
+		/// NOTE: Setting the size for entries before they are added is the best solution!
+		/// By default the EntryFactory used by FastZip will set fhe file size.
+		/// </remarks>
+		public UseZip64 UseZip64
+		{
+			get { return useZip64_; }
+			set { useZip64_ = value; }
+		}
+
+		/// <summary>
+		/// Get/set a value indicating wether file dates and times should
+		/// be restored when extracting files from an archive.
+		/// </summary>
+		/// <remarks>The default value is false.</remarks>
+		public bool RestoreDateTimeOnExtract
+		{
+			get
+			{
+				return restoreDateTimeOnExtract_;
+			}
+			set
+			{
+				restoreDateTimeOnExtract_ = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set a value indicating whether file attributes should
+		/// be restored during extract operations
+		/// </summary>
+		public bool RestoreAttributesOnExtract
+		{
+			get { return restoreAttributesOnExtract_; }
+			set { restoreAttributesOnExtract_ = value; }
+		}
+
+		/// <summary>
+		/// Get/set the Compression Level that will be used
+		/// when creating the zip
+		/// </summary>
+		public Deflater.CompressionLevel CompressionLevel
+		{
+			get { return compressionLevel_; }
+			set { compressionLevel_ = value; }
+		}
+
+		#endregion Properties
+
+		#region Delegates
+
+		/// <summary>
+		/// Delegate called when confirming overwriting of files.
+		/// </summary>
+		public delegate bool ConfirmOverwriteDelegate(string fileName);
+
+		#endregion Delegates
+
+		#region CreateZip
+
+		/// <summary>
+		/// Create a zip file.
+		/// </summary>
+		/// <param name="zipFileName">The name of the zip file to create.</param>
+		/// <param name="sourceDirectory">The directory to source files from.</param>
+		/// <param name="recurse">True to recurse directories, false for no recursion.</param>
+		/// <param name="fileFilter">The <see cref="PathFilter">file filter</see> to apply.</param>
+		/// <param name="directoryFilter">The <see cref="PathFilter">directory filter</see> to apply.</param>
+		public void CreateZip(string zipFileName, string sourceDirectory,
+			bool recurse, string fileFilter, string directoryFilter)
+		{
+			CreateZip(File.Create(zipFileName), sourceDirectory, recurse, fileFilter, directoryFilter);
+		}
+
+		/// <summary>
+		/// Create a zip file/archive.
+		/// </summary>
+		/// <param name="zipFileName">The name of the zip file to create.</param>
+		/// <param name="sourceDirectory">The directory to obtain files and directories from.</param>
+		/// <param name="recurse">True to recurse directories, false for no recursion.</param>
+		/// <param name="fileFilter">The file filter to apply.</param>
+		public void CreateZip(string zipFileName, string sourceDirectory, bool recurse, string fileFilter)
+		{
+			CreateZip(File.Create(zipFileName), sourceDirectory, recurse, fileFilter, null);
+		}
+
+		/// <summary>
+		/// Create a zip archive sending output to the <paramref name="outputStream"/> passed.
+		/// </summary>
+		/// <param name="outputStream">The stream to write archive data to.</param>
+		/// <param name="sourceDirectory">The directory to source files from.</param>
+		/// <param name="recurse">True to recurse directories, false for no recursion.</param>
+		/// <param name="fileFilter">The <see cref="PathFilter">file filter</see> to apply.</param>
+		/// <param name="directoryFilter">The <see cref="PathFilter">directory filter</see> to apply.</param>
+		/// <remarks>The <paramref name="outputStream"/> is closed after creation.</remarks>
+		public void CreateZip(Stream outputStream, string sourceDirectory, bool recurse, string fileFilter, string directoryFilter)
+		{
+			NameTransform = new ZipNameTransform(sourceDirectory);
+			sourceDirectory_ = sourceDirectory;
+
+			using (outputStream_ = new ZipOutputStream(outputStream))
+			{
+				outputStream_.SetLevel((int)CompressionLevel);
+
+				if (password_ != null)
+				{
+					outputStream_.Password = password_;
+				}
+
+				outputStream_.UseZip64 = UseZip64;
+				var scanner = new FileSystemScanner(fileFilter, directoryFilter);
+				scanner.ProcessFile += ProcessFile;
+				if (this.CreateEmptyDirectories)
+				{
+					scanner.ProcessDirectory += ProcessDirectory;
+				}
+
+				if (events_ != null)
+				{
+					if (events_.FileFailure != null)
+					{
+						scanner.FileFailure += events_.FileFailure;
+					}
+
+					if (events_.DirectoryFailure != null)
+					{
+						scanner.DirectoryFailure += events_.DirectoryFailure;
+					}
+				}
+
+				scanner.Scan(sourceDirectory, recurse);
+			}
+		}
+
+		#endregion CreateZip
+
+		#region ExtractZip
+
+		/// <summary>
+		/// Extract the contents of a zip file.
+		/// </summary>
+		/// <param name="zipFileName">The zip file to extract from.</param>
+		/// <param name="targetDirectory">The directory to save extracted information in.</param>
+		/// <param name="fileFilter">A filter to apply to files.</param>
+		public void ExtractZip(string zipFileName, string targetDirectory, string fileFilter)
+		{
+			ExtractZip(zipFileName, targetDirectory, Overwrite.Always, null, fileFilter, null, restoreDateTimeOnExtract_);
+		}
+
+		/// <summary>
+		/// Extract the contents of a zip file.
+		/// </summary>
+		/// <param name="zipFileName">The zip file to extract from.</param>
+		/// <param name="targetDirectory">The directory to save extracted information in.</param>
+		/// <param name="overwrite">The style of <see cref="Overwrite">overwriting</see> to apply.</param>
+		/// <param name="confirmDelegate">A delegate to invoke when confirming overwriting.</param>
+		/// <param name="fileFilter">A filter to apply to files.</param>
+		/// <param name="directoryFilter">A filter to apply to directories.</param>
+		/// <param name="restoreDateTime">Flag indicating whether to restore the date and time for extracted files.</param>
+		/// <param name="allowParentTraversal">Allow parent directory traversal in file paths (e.g. ../file)</param>
+		public void ExtractZip(string zipFileName, string targetDirectory,
+							   Overwrite overwrite, ConfirmOverwriteDelegate confirmDelegate,
+							   string fileFilter, string directoryFilter, bool restoreDateTime, bool allowParentTraversal = false)
+		{
+			Stream inputStream = File.Open(zipFileName, FileMode.Open, FileAccess.Read, FileShare.Read);
+			ExtractZip(inputStream, targetDirectory, overwrite, confirmDelegate, fileFilter, directoryFilter, restoreDateTime, true, allowParentTraversal);
+		}
+
+		/// <summary>
+		/// Extract the contents of a zip file held in a stream.
+		/// </summary>
+		/// <param name="inputStream">The seekable input stream containing the zip to extract from.</param>
+		/// <param name="targetDirectory">The directory to save extracted information in.</param>
+		/// <param name="overwrite">The style of <see cref="Overwrite">overwriting</see> to apply.</param>
+		/// <param name="confirmDelegate">A delegate to invoke when confirming overwriting.</param>
+		/// <param name="fileFilter">A filter to apply to files.</param>
+		/// <param name="directoryFilter">A filter to apply to directories.</param>
+		/// <param name="restoreDateTime">Flag indicating whether to restore the date and time for extracted files.</param>
+		/// <param name="isStreamOwner">Flag indicating whether the inputStream will be closed by this method.</param>
+		/// <param name="allowParentTraversal">Allow parent directory traversal in file paths (e.g. ../file)</param>
+		public void ExtractZip(Stream inputStream, string targetDirectory,
+					   Overwrite overwrite, ConfirmOverwriteDelegate confirmDelegate,
+					   string fileFilter, string directoryFilter, bool restoreDateTime,
+					   bool isStreamOwner, bool allowParentTraversal = false)
+		{
+			if ((overwrite == Overwrite.Prompt) && (confirmDelegate == null))
+			{
+				throw new ArgumentNullException(nameof(confirmDelegate));
+			}
+
+			continueRunning_ = true;
+			overwrite_ = overwrite;
+			confirmDelegate_ = confirmDelegate;
+			extractNameTransform_ = new WindowsNameTransform(targetDirectory, allowParentTraversal);
+
+			fileFilter_ = new NameFilter(fileFilter);
+			directoryFilter_ = new NameFilter(directoryFilter);
+			restoreDateTimeOnExtract_ = restoreDateTime;
+
+			using (zipFile_ = new ZipFile(inputStream, !isStreamOwner))
+			{
+				if (password_ != null)
+				{
+					zipFile_.Password = password_;
+				}
+
+				System.Collections.IEnumerator enumerator = zipFile_.GetEnumerator();
+				while (continueRunning_ && enumerator.MoveNext())
+				{
+					var entry = (ZipEntry)enumerator.Current;
+					if (entry.IsFile)
+					{
+						// TODO Path.GetDirectory can fail here on invalid characters.
+						if (directoryFilter_.IsMatch(Path.GetDirectoryName(entry.Name)) && fileFilter_.IsMatch(entry.Name))
+						{
+							ExtractEntry(entry);
+						}
+					}
+					else if (entry.IsDirectory)
+					{
+						if (directoryFilter_.IsMatch(entry.Name) && CreateEmptyDirectories)
+						{
+							ExtractEntry(entry);
+						}
+					}
+					else
+					{
+						// Do nothing for volume labels etc...
+					}
+				}
+			}
+		}
+
+		#endregion ExtractZip
+
+		#region Internal Processing
+
+		private void ProcessDirectory(object sender, DirectoryEventArgs e)
+		{
+			if (!e.HasMatchingFiles && CreateEmptyDirectories)
+			{
+				if (events_ != null)
+				{
+					events_.OnProcessDirectory(e.Name, e.HasMatchingFiles);
+				}
+
+				if (e.ContinueRunning)
+				{
+					if (e.Name != sourceDirectory_)
+					{
+						ZipEntry entry = entryFactory_.MakeDirectoryEntry(e.Name);
+						outputStream_.PutNextEntry(entry);
+					}
+				}
+			}
+		}
+
+		private void ProcessFile(object sender, ScanEventArgs e)
+		{
+			if ((events_ != null) && (events_.ProcessFile != null))
+			{
+				events_.ProcessFile(sender, e);
+			}
+
+			if (e.ContinueRunning)
+			{
+				try
+				{
+					// The open below is equivalent to OpenRead which gaurantees that if opened the
+					// file will not be changed by subsequent openers, but precludes opening in some cases
+					// were it could succeed. ie the open may fail as its already open for writing and the share mode should reflect that.
+					using (FileStream stream = File.Open(e.Name, FileMode.Open, FileAccess.Read, FileShare.Read))
+					{
+						ZipEntry entry = entryFactory_.MakeFileEntry(e.Name);
+						outputStream_.PutNextEntry(entry);
+						AddFileContents(e.Name, stream);
+					}
+				}
+				catch (Exception ex)
+				{
+					if (events_ != null)
+					{
+						continueRunning_ = events_.OnFileFailure(e.Name, ex);
+					}
+					else
+					{
+						continueRunning_ = false;
+						throw;
+					}
+				}
+			}
+		}
+
+		private void AddFileContents(string name, Stream stream)
+		{
+			if (stream == null)
+			{
+				throw new ArgumentNullException(nameof(stream));
+			}
+
+			if (buffer_ == null)
+			{
+				buffer_ = new byte[4096];
+			}
+
+			if ((events_ != null) && (events_.Progress != null))
+			{
+				StreamUtils.Copy(stream, outputStream_, buffer_,
+					events_.Progress, events_.ProgressInterval, this, name);
+			}
+			else
+			{
+				StreamUtils.Copy(stream, outputStream_, buffer_);
+			}
+
+			if (events_ != null)
+			{
+				continueRunning_ = events_.OnCompletedFile(name);
+			}
+		}
+
+		private void ExtractFileEntry(ZipEntry entry, string targetName)
+		{
+			bool proceed = true;
+			if (overwrite_ != Overwrite.Always)
+			{
+				if (File.Exists(targetName))
+				{
+					if ((overwrite_ == Overwrite.Prompt) && (confirmDelegate_ != null))
+					{
+						proceed = confirmDelegate_(targetName);
+					}
+					else
+					{
+						proceed = false;
+					}
+				}
+			}
+
+			if (proceed)
+			{
+				if (events_ != null)
+				{
+					continueRunning_ = events_.OnProcessFile(entry.Name);
+				}
+
+				if (continueRunning_)
+				{
+					try
+					{
+						using (FileStream outputStream = File.Create(targetName))
+						{
+							if (buffer_ == null)
+							{
+								buffer_ = new byte[4096];
+							}
+							if ((events_ != null) && (events_.Progress != null))
+							{
+								StreamUtils.Copy(zipFile_.GetInputStream(entry), outputStream, buffer_,
+									events_.Progress, events_.ProgressInterval, this, entry.Name, entry.Size);
+							}
+							else
+							{
+								StreamUtils.Copy(zipFile_.GetInputStream(entry), outputStream, buffer_);
+							}
+
+							if (events_ != null)
+							{
+								continueRunning_ = events_.OnCompletedFile(entry.Name);
+							}
+						}
+
+						if (restoreDateTimeOnExtract_)
+						{
+							File.SetLastWriteTime(targetName, entry.DateTime);
+						}
+
+						if (RestoreAttributesOnExtract && entry.IsDOSEntry && (entry.ExternalFileAttributes != -1))
+						{
+							var fileAttributes = (FileAttributes)entry.ExternalFileAttributes;
+							// TODO: FastZip - Setting of other file attributes on extraction is a little trickier.
+							fileAttributes &= (FileAttributes.Archive | FileAttributes.Normal | FileAttributes.ReadOnly | FileAttributes.Hidden);
+							File.SetAttributes(targetName, fileAttributes);
+						}
+					}
+					catch (Exception ex)
+					{
+						if (events_ != null)
+						{
+							continueRunning_ = events_.OnFileFailure(targetName, ex);
+						}
+						else
+						{
+							continueRunning_ = false;
+							throw;
+						}
+					}
+				}
+			}
+		}
+
+		private void ExtractEntry(ZipEntry entry)
+		{
+			bool doExtraction = entry.IsCompressionMethodSupported();
+			string targetName = entry.Name;
+
+			if (doExtraction)
+			{
+				if (entry.IsFile)
+				{
+					targetName = extractNameTransform_.TransformFile(targetName);
+				}
+				else if (entry.IsDirectory)
+				{
+					targetName = extractNameTransform_.TransformDirectory(targetName);
+				}
+
+				doExtraction = !(string.IsNullOrEmpty(targetName));
+			}
+
+			// TODO: Fire delegate/throw exception were compression method not supported, or name is invalid?
+
+			string dirName = null;
+
+			if (doExtraction)
+			{
+				if (entry.IsDirectory)
+				{
+					dirName = targetName;
+				}
+				else
+				{
+					dirName = Path.GetDirectoryName(Path.GetFullPath(targetName));
+				}
+			}
+
+			if (doExtraction && !Directory.Exists(dirName))
+			{
+				if (!entry.IsDirectory || CreateEmptyDirectories)
+				{
+					try
+					{
+						Directory.CreateDirectory(dirName);
+					}
+					catch (Exception ex)
+					{
+						doExtraction = false;
+						if (events_ != null)
+						{
+							if (entry.IsDirectory)
+							{
+								continueRunning_ = events_.OnDirectoryFailure(targetName, ex);
+							}
+							else
+							{
+								continueRunning_ = events_.OnFileFailure(targetName, ex);
+							}
+						}
+						else
+						{
+							continueRunning_ = false;
+							throw;
+						}
+					}
+				}
+			}
+
+			if (doExtraction && entry.IsFile)
+			{
+				ExtractFileEntry(entry, targetName);
+			}
+		}
+
+		private static int MakeExternalAttributes(FileInfo info)
+		{
+			return (int)info.Attributes;
+		}
+
+		private static bool NameIsValid(string name)
+		{
+			return !string.IsNullOrEmpty(name) &&
+				(name.IndexOfAny(Path.GetInvalidPathChars()) < 0);
+		}
+
+		#endregion Internal Processing
+
+		#region Instance Fields
+
+		private bool continueRunning_;
+		private byte[] buffer_;
+		private ZipOutputStream outputStream_;
+		private ZipFile zipFile_;
+		private string sourceDirectory_;
+		private NameFilter fileFilter_;
+		private NameFilter directoryFilter_;
+		private Overwrite overwrite_;
+		private ConfirmOverwriteDelegate confirmDelegate_;
+
+		private bool restoreDateTimeOnExtract_;
+		private bool restoreAttributesOnExtract_;
+		private bool createEmptyDirectories_;
+		private FastZipEvents events_;
+		private IEntryFactory entryFactory_ = new ZipEntryFactory();
+		private INameTransform extractNameTransform_;
+		private UseZip64 useZip64_ = UseZip64.Dynamic;
+		private CompressionLevel compressionLevel_ = CompressionLevel.DEFAULT_COMPRESSION;
+
+		private string password_;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/IEntryFactory.cs

@@ -0,0 +1,54 @@
+using ICSharpCode.SharpZipLib.Core;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// Defines factory methods for creating new <see cref="ZipEntry"></see> values.
+	/// </summary>
+	public interface IEntryFactory
+	{
+		/// <summary>
+		/// Create a <see cref="ZipEntry"/> for a file given its name
+		/// </summary>
+		/// <param name="fileName">The name of the file to create an entry for.</param>
+		/// <returns>Returns a <see cref="ZipEntry">file entry</see> based on the <paramref name="fileName"/> passed.</returns>
+		ZipEntry MakeFileEntry(string fileName);
+
+		/// <summary>
+		/// Create a <see cref="ZipEntry"/> for a file given its name
+		/// </summary>
+		/// <param name="fileName">The name of the file to create an entry for.</param>
+		/// <param name="useFileSystem">If true get details from the file system if the file exists.</param>
+		/// <returns>Returns a <see cref="ZipEntry">file entry</see> based on the <paramref name="fileName"/> passed.</returns>
+		ZipEntry MakeFileEntry(string fileName, bool useFileSystem);
+
+		/// <summary>
+		/// Create a <see cref="ZipEntry"/> for a file given its actual name and optional override name
+		/// </summary>
+		/// <param name="fileName">The name of the file to create an entry for.</param>
+		/// <param name="entryName">An alternative name to be used for the new entry. Null if not applicable.</param>
+		/// <param name="useFileSystem">If true get details from the file system if the file exists.</param>
+		/// <returns>Returns a <see cref="ZipEntry">file entry</see> based on the <paramref name="fileName"/> passed.</returns>
+		ZipEntry MakeFileEntry(string fileName, string entryName, bool useFileSystem);
+
+		/// <summary>
+		/// Create a <see cref="ZipEntry"/> for a directory given its name
+		/// </summary>
+		/// <param name="directoryName">The name of the directory to create an entry for.</param>
+		/// <returns>Returns a <see cref="ZipEntry">directory entry</see> based on the <paramref name="directoryName"/> passed.</returns>
+		ZipEntry MakeDirectoryEntry(string directoryName);
+
+		/// <summary>
+		/// Create a <see cref="ZipEntry"/> for a directory given its name
+		/// </summary>
+		/// <param name="directoryName">The name of the directory to create an entry for.</param>
+		/// <param name="useFileSystem">If true get details from the file system for this directory if it exists.</param>
+		/// <returns>Returns a <see cref="ZipEntry">directory entry</see> based on the <paramref name="directoryName"/> passed.</returns>
+		ZipEntry MakeDirectoryEntry(string directoryName, bool useFileSystem);
+
+		/// <summary>
+		/// Get/set the <see cref="INameTransform"></see> applicable.
+		/// </summary>
+		INameTransform NameTransform { get; set; }
+	}
+}

ICSharpCode.SharpZipLib/Zip/WindowsNameTransform.cs

@@ -0,0 +1,258 @@
+using ICSharpCode.SharpZipLib.Core;
+using System;
+using System.IO;
+using System.Text;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// WindowsNameTransform transforms <see cref="ZipFile"/> names to windows compatible ones.
+	/// </summary>
+	public class WindowsNameTransform : INameTransform
+	{
+		/// <summary>
+		///  The maximum windows path name permitted.
+		/// </summary>
+		/// <remarks>This may not valid for all windows systems - CE?, etc but I cant find the equivalent in the CLR.</remarks>
+		private const int MaxPath = 260;
+
+		private string _baseDirectory;
+		private bool _trimIncomingPaths;
+		private char _replacementChar = '_';
+		private bool _allowParentTraversal;
+
+		/// <summary>
+		/// In this case we need Windows' invalid path characters.
+		/// Path.GetInvalidPathChars() only returns a subset invalid on all platforms.
+		/// </summary>
+		private static readonly char[] InvalidEntryChars = new char[] {
+			'"', '<', '>', '|', '\0', '\u0001', '\u0002', '\u0003', '\u0004', '\u0005',
+			'\u0006', '\a', '\b', '\t', '\n', '\v', '\f', '\r', '\u000e', '\u000f',
+			'\u0010', '\u0011', '\u0012', '\u0013', '\u0014', '\u0015', '\u0016',
+			'\u0017', '\u0018', '\u0019', '\u001a', '\u001b', '\u001c', '\u001d',
+			'\u001e', '\u001f',
+			// extra characters for masks, etc.
+			'*', '?', ':'
+		};
+
+		/// <summary>
+		/// Initialises a new instance of <see cref="WindowsNameTransform"/>
+		/// </summary>
+		/// <param name="baseDirectory"></param>
+		/// <param name="allowParentTraversal">Allow parent directory traversal in file paths (e.g. ../file)</param>
+		public WindowsNameTransform(string baseDirectory, bool allowParentTraversal = false)
+		{
+			BaseDirectory = baseDirectory ?? throw new ArgumentNullException(nameof(baseDirectory), "Directory name is invalid");
+			AllowParentTraversal = allowParentTraversal;
+		}
+
+		/// <summary>
+		/// Initialise a default instance of <see cref="WindowsNameTransform"/>
+		/// </summary>
+		public WindowsNameTransform()
+		{
+			// Do nothing.
+		}
+
+		/// <summary>
+		/// Gets or sets a value containing the target directory to prefix values with.
+		/// </summary>
+		public string BaseDirectory
+		{
+			get { return _baseDirectory; }
+			set
+			{
+				if (value == null)
+				{
+					throw new ArgumentNullException(nameof(value));
+				}
+
+				_baseDirectory = Path.GetFullPath(value);
+			}
+		}
+
+		/// <summary>
+		/// Allow parent directory traversal in file paths (e.g. ../file)
+		/// </summary>
+		public bool AllowParentTraversal
+		{
+			get => _allowParentTraversal;
+			set => _allowParentTraversal = value;
+		}
+
+		/// <summary>
+		/// Gets or sets a value indicating wether paths on incoming values should be removed.
+		/// </summary>
+		public bool TrimIncomingPaths
+		{
+			get { return _trimIncomingPaths; }
+			set { _trimIncomingPaths = value; }
+		}
+
+		/// <summary>
+		/// Transform a Zip directory name to a windows directory name.
+		/// </summary>
+		/// <param name="name">The directory name to transform.</param>
+		/// <returns>The transformed name.</returns>
+		public string TransformDirectory(string name)
+		{
+			name = TransformFile(name);
+			if (name.Length > 0)
+			{
+				while (name.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal))
+				{
+					name = name.Remove(name.Length - 1, 1);
+				}
+			}
+			else
+			{
+				throw new InvalidNameException("Cannot have an empty directory name");
+			}
+			return name;
+		}
+
+		/// <summary>
+		/// Transform a Zip format file name to a windows style one.
+		/// </summary>
+		/// <param name="name">The file name to transform.</param>
+		/// <returns>The transformed name.</returns>
+		public string TransformFile(string name)
+		{
+			if (name != null)
+			{
+				name = MakeValidName(name, _replacementChar);
+
+				if (_trimIncomingPaths)
+				{
+					name = Path.GetFileName(name);
+				}
+
+				// This may exceed windows length restrictions.
+				// Combine will throw a PathTooLongException in that case.
+				if (_baseDirectory != null)
+				{
+					name = Path.Combine(_baseDirectory, name);
+
+					if (!_allowParentTraversal && !Path.GetFullPath(name).StartsWith(_baseDirectory, StringComparison.InvariantCultureIgnoreCase))
+					{
+						throw new InvalidNameException("Parent traversal in paths is not allowed");
+					}
+				}
+			}
+			else
+			{
+				name = string.Empty;
+			}
+			return name;
+		}
+
+		/// <summary>
+		/// Test a name to see if it is a valid name for a windows filename as extracted from a Zip archive.
+		/// </summary>
+		/// <param name="name">The name to test.</param>
+		/// <returns>Returns true if the name is a valid zip name; false otherwise.</returns>
+		/// <remarks>The filename isnt a true windows path in some fundamental ways like no absolute paths, no rooted paths etc.</remarks>
+		public static bool IsValidName(string name)
+		{
+			bool result =
+				(name != null) &&
+				(name.Length <= MaxPath) &&
+				(string.Compare(name, MakeValidName(name, '_'), StringComparison.Ordinal) == 0)
+				;
+
+			return result;
+		}
+
+		/// <summary>
+		/// Force a name to be valid by replacing invalid characters with a fixed value
+		/// </summary>
+		/// <param name="name">The name to make valid</param>
+		/// <param name="replacement">The replacement character to use for any invalid characters.</param>
+		/// <returns>Returns a valid name</returns>
+		public static string MakeValidName(string name, char replacement)
+		{
+			if (name == null)
+			{
+				throw new ArgumentNullException(nameof(name));
+			}
+
+			name = WindowsPathUtils.DropPathRoot(name.Replace("/", Path.DirectorySeparatorChar.ToString()));
+
+			// Drop any leading slashes.
+			while ((name.Length > 0) && (name[0] == Path.DirectorySeparatorChar))
+			{
+				name = name.Remove(0, 1);
+			}
+
+			// Drop any trailing slashes.
+			while ((name.Length > 0) && (name[name.Length - 1] == Path.DirectorySeparatorChar))
+			{
+				name = name.Remove(name.Length - 1, 1);
+			}
+
+			// Convert consecutive \\ characters to \
+			int index = name.IndexOf(string.Format("{0}{0}", Path.DirectorySeparatorChar), StringComparison.Ordinal);
+			while (index >= 0)
+			{
+				name = name.Remove(index, 1);
+				index = name.IndexOf(string.Format("{0}{0}", Path.DirectorySeparatorChar), StringComparison.Ordinal);
+			}
+
+			// Convert any invalid characters using the replacement one.
+			index = name.IndexOfAny(InvalidEntryChars);
+			if (index >= 0)
+			{
+				var builder = new StringBuilder(name);
+
+				while (index >= 0)
+				{
+					builder[index] = replacement;
+
+					if (index >= name.Length)
+					{
+						index = -1;
+					}
+					else
+					{
+						index = name.IndexOfAny(InvalidEntryChars, index + 1);
+					}
+				}
+				name = builder.ToString();
+			}
+
+			// Check for names greater than MaxPath characters.
+			// TODO: Were is CLR version of MaxPath defined?  Can't find it in Environment.
+			if (name.Length > MaxPath)
+			{
+				throw new PathTooLongException();
+			}
+
+			return name;
+		}
+
+		/// <summary>
+		/// Gets or set the character to replace invalid characters during transformations.
+		/// </summary>
+		public char Replacement
+		{
+			get { return _replacementChar; }
+			set
+			{
+				for (int i = 0; i < InvalidEntryChars.Length; ++i)
+				{
+					if (InvalidEntryChars[i] == value)
+					{
+						throw new ArgumentException("invalid path character");
+					}
+				}
+
+				if ((value == Path.DirectorySeparatorChar) || (value == Path.AltDirectorySeparatorChar))
+				{
+					throw new ArgumentException("invalid replacement character");
+				}
+
+				_replacementChar = value;
+			}
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipConstants.cs

@@ -0,0 +1,497 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	#region Enumerations
+
+	/// <summary>
+	/// Determines how entries are tested to see if they should use Zip64 extensions or not.
+	/// </summary>
+	public enum UseZip64
+	{
+		/// <summary>
+		/// Zip64 will not be forced on entries during processing.
+		/// </summary>
+		/// <remarks>An entry can have this overridden if required <see cref="ZipEntry.ForceZip64"></see></remarks>
+		Off,
+
+		/// <summary>
+		/// Zip64 should always be used.
+		/// </summary>
+		On,
+
+		/// <summary>
+		/// #ZipLib will determine use based on entry values when added to archive.
+		/// </summary>
+		Dynamic,
+	}
+
+	/// <summary>
+	/// The kind of compression used for an entry in an archive
+	/// </summary>
+	public enum CompressionMethod
+	{
+		/// <summary>
+		/// A direct copy of the file contents is held in the archive
+		/// </summary>
+		Stored = 0,
+
+		/// <summary>
+		/// Common Zip compression method using a sliding dictionary
+		/// of up to 32KB and secondary compression from Huffman/Shannon-Fano trees
+		/// </summary>
+		Deflated = 8,
+
+		/// <summary>
+		/// An extension to deflate with a 64KB window. Not supported by #Zip currently
+		/// </summary>
+		Deflate64 = 9,
+
+		/// <summary>
+		/// BZip2 compression. Not supported by #Zip.
+		/// </summary>
+		BZip2 = 12,
+
+		/// <summary>
+		/// WinZip special for AES encryption, Now supported by #Zip.
+		/// </summary>
+		WinZipAES = 99,
+	}
+
+	/// <summary>
+	/// Identifies the encryption algorithm used for an entry
+	/// </summary>
+	public enum EncryptionAlgorithm
+	{
+		/// <summary>
+		/// No encryption has been used.
+		/// </summary>
+		None = 0,
+
+		/// <summary>
+		/// Encrypted using PKZIP 2.0 or 'classic' encryption.
+		/// </summary>
+		PkzipClassic = 1,
+
+		/// <summary>
+		/// DES encryption has been used.
+		/// </summary>
+		Des = 0x6601,
+
+		/// <summary>
+		/// RC2 encryption has been used for encryption.
+		/// </summary>
+		RC2 = 0x6602,
+
+		/// <summary>
+		/// Triple DES encryption with 168 bit keys has been used for this entry.
+		/// </summary>
+		TripleDes168 = 0x6603,
+
+		/// <summary>
+		/// Triple DES with 112 bit keys has been used for this entry.
+		/// </summary>
+		TripleDes112 = 0x6609,
+
+		/// <summary>
+		/// AES 128 has been used for encryption.
+		/// </summary>
+		Aes128 = 0x660e,
+
+		/// <summary>
+		/// AES 192 has been used for encryption.
+		/// </summary>
+		Aes192 = 0x660f,
+
+		/// <summary>
+		/// AES 256 has been used for encryption.
+		/// </summary>
+		Aes256 = 0x6610,
+
+		/// <summary>
+		/// RC2 corrected has been used for encryption.
+		/// </summary>
+		RC2Corrected = 0x6702,
+
+		/// <summary>
+		/// Blowfish has been used for encryption.
+		/// </summary>
+		Blowfish = 0x6720,
+
+		/// <summary>
+		/// Twofish has been used for encryption.
+		/// </summary>
+		Twofish = 0x6721,
+
+		/// <summary>
+		/// RC4 has been used for encryption.
+		/// </summary>
+		RC4 = 0x6801,
+
+		/// <summary>
+		/// An unknown algorithm has been used for encryption.
+		/// </summary>
+		Unknown = 0xffff
+	}
+
+	/// <summary>
+	/// Defines the contents of the general bit flags field for an archive entry.
+	/// </summary>
+	[Flags]
+	public enum GeneralBitFlags
+	{
+		/// <summary>
+		/// Bit 0 if set indicates that the file is encrypted
+		/// </summary>
+		Encrypted = 0x0001,
+
+		/// <summary>
+		/// Bits 1 and 2 - Two bits defining the compression method (only for Method 6 Imploding and 8,9 Deflating)
+		/// </summary>
+		Method = 0x0006,
+
+		/// <summary>
+		/// Bit 3 if set indicates a trailing data desciptor is appended to the entry data
+		/// </summary>
+		Descriptor = 0x0008,
+
+		/// <summary>
+		/// Bit 4 is reserved for use with method 8 for enhanced deflation
+		/// </summary>
+		ReservedPKware4 = 0x0010,
+
+		/// <summary>
+		/// Bit 5 if set indicates the file contains Pkzip compressed patched data.
+		/// Requires version 2.7 or greater.
+		/// </summary>
+		Patched = 0x0020,
+
+		/// <summary>
+		/// Bit 6 if set indicates strong encryption has been used for this entry.
+		/// </summary>
+		StrongEncryption = 0x0040,
+
+		/// <summary>
+		/// Bit 7 is currently unused
+		/// </summary>
+		Unused7 = 0x0080,
+
+		/// <summary>
+		/// Bit 8 is currently unused
+		/// </summary>
+		Unused8 = 0x0100,
+
+		/// <summary>
+		/// Bit 9 is currently unused
+		/// </summary>
+		Unused9 = 0x0200,
+
+		/// <summary>
+		/// Bit 10 is currently unused
+		/// </summary>
+		Unused10 = 0x0400,
+
+		/// <summary>
+		/// Bit 11 if set indicates the filename and
+		/// comment fields for this file must be encoded using UTF-8.
+		/// </summary>
+		UnicodeText = 0x0800,
+
+		/// <summary>
+		/// Bit 12 is documented as being reserved by PKware for enhanced compression.
+		/// </summary>
+		EnhancedCompress = 0x1000,
+
+		/// <summary>
+		/// Bit 13 if set indicates that values in the local header are masked to hide
+		/// their actual values, and the central directory is encrypted.
+		/// </summary>
+		/// <remarks>
+		/// Used when encrypting the central directory contents.
+		/// </remarks>
+		HeaderMasked = 0x2000,
+
+		/// <summary>
+		/// Bit 14 is documented as being reserved for use by PKware
+		/// </summary>
+		ReservedPkware14 = 0x4000,
+
+		/// <summary>
+		/// Bit 15 is documented as being reserved for use by PKware
+		/// </summary>
+		ReservedPkware15 = 0x8000
+	}
+
+	#endregion Enumerations
+
+	/// <summary>
+	/// This class contains constants used for Zip format files
+	/// </summary>
+	public static class ZipConstants
+	{
+		#region Versions
+
+		/// <summary>
+		/// The version made by field for entries in the central header when created by this library
+		/// </summary>
+		/// <remarks>
+		/// This is also the Zip version for the library when comparing against the version required to extract
+		/// for an entry.  See <see cref="ZipEntry.CanDecompress"/>.
+		/// </remarks>
+		public const int VersionMadeBy = 51; // was 45 before AES
+
+		/// <summary>
+		/// The version made by field for entries in the central header when created by this library
+		/// </summary>
+		/// <remarks>
+		/// This is also the Zip version for the library when comparing against the version required to extract
+		/// for an entry.  See <see cref="ZipInputStream.CanDecompressEntry">ZipInputStream.CanDecompressEntry</see>.
+		/// </remarks>
+		[Obsolete("Use VersionMadeBy instead")]
+		public const int VERSION_MADE_BY = 51;
+
+		/// <summary>
+		/// The minimum version required to support strong encryption
+		/// </summary>
+		public const int VersionStrongEncryption = 50;
+
+		/// <summary>
+		/// The minimum version required to support strong encryption
+		/// </summary>
+		[Obsolete("Use VersionStrongEncryption instead")]
+		public const int VERSION_STRONG_ENCRYPTION = 50;
+
+		/// <summary>
+		/// Version indicating AES encryption
+		/// </summary>
+		public const int VERSION_AES = 51;
+
+		/// <summary>
+		/// The version required for Zip64 extensions (4.5 or higher)
+		/// </summary>
+		public const int VersionZip64 = 45;
+
+		#endregion Versions
+
+		#region Header Sizes
+
+		/// <summary>
+		/// Size of local entry header (excluding variable length fields at end)
+		/// </summary>
+		public const int LocalHeaderBaseSize = 30;
+
+		/// <summary>
+		/// Size of local entry header (excluding variable length fields at end)
+		/// </summary>
+		[Obsolete("Use LocalHeaderBaseSize instead")]
+		public const int LOCHDR = 30;
+
+		/// <summary>
+		/// Size of Zip64 data descriptor
+		/// </summary>
+		public const int Zip64DataDescriptorSize = 24;
+
+		/// <summary>
+		/// Size of data descriptor
+		/// </summary>
+		public const int DataDescriptorSize = 16;
+
+		/// <summary>
+		/// Size of data descriptor
+		/// </summary>
+		[Obsolete("Use DataDescriptorSize instead")]
+		public const int EXTHDR = 16;
+
+		/// <summary>
+		/// Size of central header entry (excluding variable fields)
+		/// </summary>
+		public const int CentralHeaderBaseSize = 46;
+
+		/// <summary>
+		/// Size of central header entry
+		/// </summary>
+		[Obsolete("Use CentralHeaderBaseSize instead")]
+		public const int CENHDR = 46;
+
+		/// <summary>
+		/// Size of end of central record (excluding variable fields)
+		/// </summary>
+		public const int EndOfCentralRecordBaseSize = 22;
+
+		/// <summary>
+		/// Size of end of central record (excluding variable fields)
+		/// </summary>
+		[Obsolete("Use EndOfCentralRecordBaseSize instead")]
+		public const int ENDHDR = 22;
+
+		/// <summary>
+		/// Size of 'classic' cryptographic header stored before any entry data
+		/// </summary>
+		public const int CryptoHeaderSize = 12;
+
+		/// <summary>
+		/// Size of cryptographic header stored before entry data
+		/// </summary>
+		[Obsolete("Use CryptoHeaderSize instead")]
+		public const int CRYPTO_HEADER_SIZE = 12;
+
+		#endregion Header Sizes
+
+		#region Header Signatures
+
+		/// <summary>
+		/// Signature for local entry header
+		/// </summary>
+		public const int LocalHeaderSignature = 'P' | ('K' << 8) | (3 << 16) | (4 << 24);
+
+		/// <summary>
+		/// Signature for local entry header
+		/// </summary>
+		[Obsolete("Use LocalHeaderSignature instead")]
+		public const int LOCSIG = 'P' | ('K' << 8) | (3 << 16) | (4 << 24);
+
+		/// <summary>
+		/// Signature for spanning entry
+		/// </summary>
+		public const int SpanningSignature = 'P' | ('K' << 8) | (7 << 16) | (8 << 24);
+
+		/// <summary>
+		/// Signature for spanning entry
+		/// </summary>
+		[Obsolete("Use SpanningSignature instead")]
+		public const int SPANNINGSIG = 'P' | ('K' << 8) | (7 << 16) | (8 << 24);
+
+		/// <summary>
+		/// Signature for temporary spanning entry
+		/// </summary>
+		public const int SpanningTempSignature = 'P' | ('K' << 8) | ('0' << 16) | ('0' << 24);
+
+		/// <summary>
+		/// Signature for temporary spanning entry
+		/// </summary>
+		[Obsolete("Use SpanningTempSignature instead")]
+		public const int SPANTEMPSIG = 'P' | ('K' << 8) | ('0' << 16) | ('0' << 24);
+
+		/// <summary>
+		/// Signature for data descriptor
+		/// </summary>
+		/// <remarks>
+		/// This is only used where the length, Crc, or compressed size isnt known when the
+		/// entry is created and the output stream doesnt support seeking.
+		/// The local entry cannot be 'patched' with the correct values in this case
+		/// so the values are recorded after the data prefixed by this header, as well as in the central directory.
+		/// </remarks>
+		public const int DataDescriptorSignature = 'P' | ('K' << 8) | (7 << 16) | (8 << 24);
+
+		/// <summary>
+		/// Signature for data descriptor
+		/// </summary>
+		/// <remarks>
+		/// This is only used where the length, Crc, or compressed size isnt known when the
+		/// entry is created and the output stream doesnt support seeking.
+		/// The local entry cannot be 'patched' with the correct values in this case
+		/// so the values are recorded after the data prefixed by this header, as well as in the central directory.
+		/// </remarks>
+		[Obsolete("Use DataDescriptorSignature instead")]
+		public const int EXTSIG = 'P' | ('K' << 8) | (7 << 16) | (8 << 24);
+
+		/// <summary>
+		/// Signature for central header
+		/// </summary>
+		[Obsolete("Use CentralHeaderSignature instead")]
+		public const int CENSIG = 'P' | ('K' << 8) | (1 << 16) | (2 << 24);
+
+		/// <summary>
+		/// Signature for central header
+		/// </summary>
+		public const int CentralHeaderSignature = 'P' | ('K' << 8) | (1 << 16) | (2 << 24);
+
+		/// <summary>
+		/// Signature for Zip64 central file header
+		/// </summary>
+		public const int Zip64CentralFileHeaderSignature = 'P' | ('K' << 8) | (6 << 16) | (6 << 24);
+
+		/// <summary>
+		/// Signature for Zip64 central file header
+		/// </summary>
+		[Obsolete("Use Zip64CentralFileHeaderSignature instead")]
+		public const int CENSIG64 = 'P' | ('K' << 8) | (6 << 16) | (6 << 24);
+
+		/// <summary>
+		/// Signature for Zip64 central directory locator
+		/// </summary>
+		public const int Zip64CentralDirLocatorSignature = 'P' | ('K' << 8) | (6 << 16) | (7 << 24);
+
+		/// <summary>
+		/// Signature for archive extra data signature (were headers are encrypted).
+		/// </summary>
+		public const int ArchiveExtraDataSignature = 'P' | ('K' << 8) | (6 << 16) | (7 << 24);
+
+		/// <summary>
+		/// Central header digitial signature
+		/// </summary>
+		public const int CentralHeaderDigitalSignature = 'P' | ('K' << 8) | (5 << 16) | (5 << 24);
+
+		/// <summary>
+		/// Central header digitial signature
+		/// </summary>
+		[Obsolete("Use CentralHeaderDigitalSignaure instead")]
+		public const int CENDIGITALSIG = 'P' | ('K' << 8) | (5 << 16) | (5 << 24);
+
+		/// <summary>
+		/// End of central directory record signature
+		/// </summary>
+		public const int EndOfCentralDirectorySignature = 'P' | ('K' << 8) | (5 << 16) | (6 << 24);
+
+		/// <summary>
+		/// End of central directory record signature
+		/// </summary>
+		[Obsolete("Use EndOfCentralDirectorySignature instead")]
+		public const int ENDSIG = 'P' | ('K' << 8) | (5 << 16) | (6 << 24);
+
+		#endregion Header Signatures
+
+		/// <summary>
+		/// Default encoding used for string conversion.  0 gives the default system OEM code page.
+		/// Using the default code page isnt the full solution neccessarily
+		/// there are many variable factors, codepage 850 is often a good choice for
+		/// European users, however be careful about compatability.
+		/// </summary>
+		[Obsolete("Use ZipStrings instead")]
+		public static int DefaultCodePage
+		{
+			get => ZipStrings.CodePage;
+			set => ZipStrings.CodePage = value;
+		}
+
+		/// <summary> Depracated wrapper for <see cref="ZipStrings.ConvertToString(byte[], int)"/></summary>
+		[Obsolete("Use ZipStrings.ConvertToString instead")]
+		public static string ConvertToString(byte[] data, int count)
+			=> ZipStrings.ConvertToString(data, count);
+
+		/// <summary> Depracated wrapper for <see cref="ZipStrings.ConvertToString(byte[])"/></summary>
+		[Obsolete("Use ZipStrings.ConvertToString instead")]
+		public static string ConvertToString(byte[] data)
+			=> ZipStrings.ConvertToString(data);
+
+		/// <summary> Depracated wrapper for <see cref="ZipStrings.ConvertToStringExt(int, byte[], int)"/></summary>
+		[Obsolete("Use ZipStrings.ConvertToStringExt instead")]
+		public static string ConvertToStringExt(int flags, byte[] data, int count)
+			=> ZipStrings.ConvertToStringExt(flags, data, count);
+
+		/// <summary> Depracated wrapper for <see cref="ZipStrings.ConvertToStringExt(int, byte[])"/></summary>
+		[Obsolete("Use ZipStrings.ConvertToStringExt instead")]
+		public static string ConvertToStringExt(int flags, byte[] data)
+			=> ZipStrings.ConvertToStringExt(flags, data);
+
+		/// <summary> Depracated wrapper for <see cref="ZipStrings.ConvertToArray(string)"/></summary>
+		[Obsolete("Use ZipStrings.ConvertToArray instead")]
+		public static byte[] ConvertToArray(string str)
+			=> ZipStrings.ConvertToArray(str);
+
+		/// <summary> Depracated wrapper for <see cref="ZipStrings.ConvertToArray(int, string)"/></summary>
+		[Obsolete("Use ZipStrings.ConvertToArray instead")]
+		public static byte[] ConvertToArray(int flags, string str)
+			=> ZipStrings.ConvertToArray(flags, str);
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipEntryFactory.cs

@@ -0,0 +1,375 @@
+using ICSharpCode.SharpZipLib.Core;
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// Basic implementation of <see cref="IEntryFactory"></see>
+	/// </summary>
+	public class ZipEntryFactory : IEntryFactory
+	{
+		#region Enumerations
+
+		/// <summary>
+		/// Defines the possible values to be used for the <see cref="ZipEntry.DateTime"/>.
+		/// </summary>
+		public enum TimeSetting
+		{
+			/// <summary>
+			/// Use the recorded LastWriteTime value for the file.
+			/// </summary>
+			LastWriteTime,
+
+			/// <summary>
+			/// Use the recorded LastWriteTimeUtc value for the file
+			/// </summary>
+			LastWriteTimeUtc,
+
+			/// <summary>
+			/// Use the recorded CreateTime value for the file.
+			/// </summary>
+			CreateTime,
+
+			/// <summary>
+			/// Use the recorded CreateTimeUtc value for the file.
+			/// </summary>
+			CreateTimeUtc,
+
+			/// <summary>
+			/// Use the recorded LastAccessTime value for the file.
+			/// </summary>
+			LastAccessTime,
+
+			/// <summary>
+			/// Use the recorded LastAccessTimeUtc value for the file.
+			/// </summary>
+			LastAccessTimeUtc,
+
+			/// <summary>
+			/// Use a fixed value.
+			/// </summary>
+			/// <remarks>The actual <see cref="DateTime"/> value used can be
+			/// specified via the <see cref="ZipEntryFactory(DateTime)"/> constructor or
+			/// using the <see cref="ZipEntryFactory(TimeSetting)"/> with the setting set
+			/// to <see cref="TimeSetting.Fixed"/> which will use the <see cref="DateTime"/> when this class was constructed.
+			/// The <see cref="FixedDateTime"/> property can also be used to set this value.</remarks>
+			Fixed,
+		}
+
+		#endregion Enumerations
+
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a new instance of the <see cref="ZipEntryFactory"/> class.
+		/// </summary>
+		/// <remarks>A default <see cref="INameTransform"/>, and the LastWriteTime for files is used.</remarks>
+		public ZipEntryFactory()
+		{
+			nameTransform_ = new ZipNameTransform();
+			isUnicodeText_ = ZipStrings.UseUnicode;
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="ZipEntryFactory"/> using the specified <see cref="TimeSetting"/>
+		/// </summary>
+		/// <param name="timeSetting">The <see cref="TimeSetting">time setting</see> to use when creating <see cref="ZipEntry">Zip entries</see>.</param>
+		public ZipEntryFactory(TimeSetting timeSetting) : this()
+		{
+			timeSetting_ = timeSetting;
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="ZipEntryFactory"/> using the specified <see cref="DateTime"/>
+		/// </summary>
+		/// <param name="time">The time to set all <see cref="ZipEntry.DateTime"/> values to.</param>
+		public ZipEntryFactory(DateTime time) : this()
+		{
+			timeSetting_ = TimeSetting.Fixed;
+			FixedDateTime = time;
+		}
+
+		#endregion Constructors
+
+		#region Properties
+
+		/// <summary>
+		/// Get / set the <see cref="INameTransform"/> to be used when creating new <see cref="ZipEntry"/> values.
+		/// </summary>
+		/// <remarks>
+		/// Setting this property to null will cause a default <see cref="ZipNameTransform">name transform</see> to be used.
+		/// </remarks>
+		public INameTransform NameTransform
+		{
+			get { return nameTransform_; }
+			set
+			{
+				if (value == null)
+				{
+					nameTransform_ = new ZipNameTransform();
+				}
+				else
+				{
+					nameTransform_ = value;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Get / set the <see cref="TimeSetting"/> in use.
+		/// </summary>
+		public TimeSetting Setting
+		{
+			get { return timeSetting_; }
+			set { timeSetting_ = value; }
+		}
+
+		/// <summary>
+		/// Get / set the <see cref="DateTime"/> value to use when <see cref="Setting"/> is set to <see cref="TimeSetting.Fixed"/>
+		/// </summary>
+		public DateTime FixedDateTime
+		{
+			get { return fixedDateTime_; }
+			set
+			{
+				if (value.Year < 1970)
+				{
+					throw new ArgumentException("Value is too old to be valid", nameof(value));
+				}
+				fixedDateTime_ = value;
+			}
+		}
+
+		/// <summary>
+		/// A bitmask defining the attributes to be retrieved from the actual file.
+		/// </summary>
+		/// <remarks>The default is to get all possible attributes from the actual file.</remarks>
+		public int GetAttributes
+		{
+			get { return getAttributes_; }
+			set { getAttributes_ = value; }
+		}
+
+		/// <summary>
+		/// A bitmask defining which attributes are to be set on.
+		/// </summary>
+		/// <remarks>By default no attributes are set on.</remarks>
+		public int SetAttributes
+		{
+			get { return setAttributes_; }
+			set { setAttributes_ = value; }
+		}
+
+		/// <summary>
+		/// Get set a value indicating wether unidoce text should be set on.
+		/// </summary>
+		public bool IsUnicodeText
+		{
+			get { return isUnicodeText_; }
+			set { isUnicodeText_ = value; }
+		}
+
+		#endregion Properties
+
+		#region IEntryFactory Members
+
+		/// <summary>
+		/// Make a new <see cref="ZipEntry"/> for a file.
+		/// </summary>
+		/// <param name="fileName">The name of the file to create a new entry for.</param>
+		/// <returns>Returns a new <see cref="ZipEntry"/> based on the <paramref name="fileName"/>.</returns>
+		public ZipEntry MakeFileEntry(string fileName)
+		{
+			return MakeFileEntry(fileName, null, true);
+		}
+
+		/// <summary>
+		/// Make a new <see cref="ZipEntry"/> for a file.
+		/// </summary>
+		/// <param name="fileName">The name of the file to create a new entry for.</param>
+		/// <param name="useFileSystem">If true entry detail is retrieved from the file system if the file exists.</param>
+		/// <returns>Returns a new <see cref="ZipEntry"/> based on the <paramref name="fileName"/>.</returns>
+		public ZipEntry MakeFileEntry(string fileName, bool useFileSystem)
+		{
+			return MakeFileEntry(fileName, null, useFileSystem);
+		}
+
+		/// <summary>
+		/// Make a new <see cref="ZipEntry"/> from a name.
+		/// </summary>
+		/// <param name="fileName">The name of the file to create a new entry for.</param>
+		/// <param name="entryName">An alternative name to be used for the new entry. Null if not applicable.</param>
+		/// <param name="useFileSystem">If true entry detail is retrieved from the file system if the file exists.</param>
+		/// <returns>Returns a new <see cref="ZipEntry"/> based on the <paramref name="fileName"/>.</returns>
+		public ZipEntry MakeFileEntry(string fileName, string entryName, bool useFileSystem)
+		{
+			var result = new ZipEntry(nameTransform_.TransformFile(!string.IsNullOrEmpty(entryName) ? entryName : fileName));
+			result.IsUnicodeText = isUnicodeText_;
+
+			int externalAttributes = 0;
+			bool useAttributes = (setAttributes_ != 0);
+
+			FileInfo fi = null;
+			if (useFileSystem)
+			{
+				fi = new FileInfo(fileName);
+			}
+
+			if ((fi != null) && fi.Exists)
+			{
+				switch (timeSetting_)
+				{
+					case TimeSetting.CreateTime:
+						result.DateTime = fi.CreationTime;
+						break;
+
+					case TimeSetting.CreateTimeUtc:
+						result.DateTime = fi.CreationTimeUtc;
+						break;
+
+					case TimeSetting.LastAccessTime:
+						result.DateTime = fi.LastAccessTime;
+						break;
+
+					case TimeSetting.LastAccessTimeUtc:
+						result.DateTime = fi.LastAccessTimeUtc;
+						break;
+
+					case TimeSetting.LastWriteTime:
+						result.DateTime = fi.LastWriteTime;
+						break;
+
+					case TimeSetting.LastWriteTimeUtc:
+						result.DateTime = fi.LastWriteTimeUtc;
+						break;
+
+					case TimeSetting.Fixed:
+						result.DateTime = fixedDateTime_;
+						break;
+
+					default:
+						throw new ZipException("Unhandled time setting in MakeFileEntry");
+				}
+
+				result.Size = fi.Length;
+
+				useAttributes = true;
+				externalAttributes = ((int)fi.Attributes & getAttributes_);
+			}
+			else
+			{
+				if (timeSetting_ == TimeSetting.Fixed)
+				{
+					result.DateTime = fixedDateTime_;
+				}
+			}
+
+			if (useAttributes)
+			{
+				externalAttributes |= setAttributes_;
+				result.ExternalFileAttributes = externalAttributes;
+			}
+
+			return result;
+		}
+
+		/// <summary>
+		/// Make a new <see cref="ZipEntry"></see> for a directory.
+		/// </summary>
+		/// <param name="directoryName">The raw untransformed name for the new directory</param>
+		/// <returns>Returns a new <see cref="ZipEntry"></see> representing a directory.</returns>
+		public ZipEntry MakeDirectoryEntry(string directoryName)
+		{
+			return MakeDirectoryEntry(directoryName, true);
+		}
+
+		/// <summary>
+		/// Make a new <see cref="ZipEntry"></see> for a directory.
+		/// </summary>
+		/// <param name="directoryName">The raw untransformed name for the new directory</param>
+		/// <param name="useFileSystem">If true entry detail is retrieved from the file system if the file exists.</param>
+		/// <returns>Returns a new <see cref="ZipEntry"></see> representing a directory.</returns>
+		public ZipEntry MakeDirectoryEntry(string directoryName, bool useFileSystem)
+		{
+			var result = new ZipEntry(nameTransform_.TransformDirectory(directoryName));
+			result.IsUnicodeText = isUnicodeText_;
+			result.Size = 0;
+
+			int externalAttributes = 0;
+
+			DirectoryInfo di = null;
+
+			if (useFileSystem)
+			{
+				di = new DirectoryInfo(directoryName);
+			}
+
+			if ((di != null) && di.Exists)
+			{
+				switch (timeSetting_)
+				{
+					case TimeSetting.CreateTime:
+						result.DateTime = di.CreationTime;
+						break;
+
+					case TimeSetting.CreateTimeUtc:
+						result.DateTime = di.CreationTimeUtc;
+						break;
+
+					case TimeSetting.LastAccessTime:
+						result.DateTime = di.LastAccessTime;
+						break;
+
+					case TimeSetting.LastAccessTimeUtc:
+						result.DateTime = di.LastAccessTimeUtc;
+						break;
+
+					case TimeSetting.LastWriteTime:
+						result.DateTime = di.LastWriteTime;
+						break;
+
+					case TimeSetting.LastWriteTimeUtc:
+						result.DateTime = di.LastWriteTimeUtc;
+						break;
+
+					case TimeSetting.Fixed:
+						result.DateTime = fixedDateTime_;
+						break;
+
+					default:
+						throw new ZipException("Unhandled time setting in MakeDirectoryEntry");
+				}
+
+				externalAttributes = ((int)di.Attributes & getAttributes_);
+			}
+			else
+			{
+				if (timeSetting_ == TimeSetting.Fixed)
+				{
+					result.DateTime = fixedDateTime_;
+				}
+			}
+
+			// Always set directory attribute on.
+			externalAttributes |= (setAttributes_ | 16);
+			result.ExternalFileAttributes = externalAttributes;
+
+			return result;
+		}
+
+		#endregion IEntryFactory Members
+
+		#region Instance Fields
+
+		private INameTransform nameTransform_;
+		private DateTime fixedDateTime_ = DateTime.Now;
+		private TimeSetting timeSetting_;
+		private bool isUnicodeText_;
+
+		private int getAttributes_ = -1;
+		private int setAttributes_;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipException.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// ZipException represents exceptions specific to Zip classes and code.
+	/// </summary>
+	public class ZipException : SharpZipBaseException
+	{
+		/// <summary>
+		/// Initialise a new instance of <see cref="ZipException" />.
+		/// </summary>
+		public ZipException()
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="ZipException" /> with its message string.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		public ZipException(string message)
+			: base(message)
+		{
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="ZipException" />.
+		/// </summary>
+		/// <param name="message">A <see cref="string"/> that describes the error.</param>
+		/// <param name="innerException">The <see cref="Exception"/> that caused this exception.</param>
+		public ZipException(string message, Exception innerException)
+			: base(message, innerException)
+		{
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipExtraData.cs

@@ -0,0 +1,979 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	// TODO: Sort out wether tagged data is useful and what a good implementation might look like.
+	// Its just a sketch of an idea at the moment.
+
+	/// <summary>
+	/// ExtraData tagged value interface.
+	/// </summary>
+	public interface ITaggedData
+	{
+		/// <summary>
+		/// Get the ID for this tagged data value.
+		/// </summary>
+		short TagID { get; }
+
+		/// <summary>
+		/// Set the contents of this instance from the data passed.
+		/// </summary>
+		/// <param name="data">The data to extract contents from.</param>
+		/// <param name="offset">The offset to begin extracting data from.</param>
+		/// <param name="count">The number of bytes to extract.</param>
+		void SetData(byte[] data, int offset, int count);
+
+		/// <summary>
+		/// Get the data representing this instance.
+		/// </summary>
+		/// <returns>Returns the data for this instance.</returns>
+		byte[] GetData();
+	}
+
+	/// <summary>
+	/// A raw binary tagged value
+	/// </summary>
+	public class RawTaggedData : ITaggedData
+	{
+		/// <summary>
+		/// Initialise a new instance.
+		/// </summary>
+		/// <param name="tag">The tag ID.</param>
+		public RawTaggedData(short tag)
+		{
+			_tag = tag;
+		}
+
+		#region ITaggedData Members
+
+		/// <summary>
+		/// Get the ID for this tagged data value.
+		/// </summary>
+		public short TagID
+		{
+			get { return _tag; }
+			set { _tag = value; }
+		}
+
+		/// <summary>
+		/// Set the data from the raw values provided.
+		/// </summary>
+		/// <param name="data">The raw data to extract values from.</param>
+		/// <param name="offset">The index to start extracting values from.</param>
+		/// <param name="count">The number of bytes available.</param>
+		public void SetData(byte[] data, int offset, int count)
+		{
+			if (data == null)
+			{
+				throw new ArgumentNullException(nameof(data));
+			}
+
+			_data = new byte[count];
+			Array.Copy(data, offset, _data, 0, count);
+		}
+
+		/// <summary>
+		/// Get the binary data representing this instance.
+		/// </summary>
+		/// <returns>The raw binary data representing this instance.</returns>
+		public byte[] GetData()
+		{
+			return _data;
+		}
+
+		#endregion ITaggedData Members
+
+		/// <summary>
+		/// Get /set the binary data representing this instance.
+		/// </summary>
+		/// <returns>The raw binary data representing this instance.</returns>
+		public byte[] Data
+		{
+			get { return _data; }
+			set { _data = value; }
+		}
+
+		#region Instance Fields
+
+		/// <summary>
+		/// The tag ID for this instance.
+		/// </summary>
+		private short _tag;
+
+		private byte[] _data;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// Class representing extended unix date time values.
+	/// </summary>
+	public class ExtendedUnixData : ITaggedData
+	{
+		/// <summary>
+		/// Flags indicate which values are included in this instance.
+		/// </summary>
+		[Flags]
+		public enum Flags : byte
+		{
+			/// <summary>
+			/// The modification time is included
+			/// </summary>
+			ModificationTime = 0x01,
+
+			/// <summary>
+			/// The access time is included
+			/// </summary>
+			AccessTime = 0x02,
+
+			/// <summary>
+			/// The create time is included.
+			/// </summary>
+			CreateTime = 0x04,
+		}
+
+		#region ITaggedData Members
+
+		/// <summary>
+		/// Get the ID
+		/// </summary>
+		public short TagID
+		{
+			get { return 0x5455; }
+		}
+
+		/// <summary>
+		/// Set the data from the raw values provided.
+		/// </summary>
+		/// <param name="data">The raw data to extract values from.</param>
+		/// <param name="index">The index to start extracting values from.</param>
+		/// <param name="count">The number of bytes available.</param>
+		public void SetData(byte[] data, int index, int count)
+		{
+			using (MemoryStream ms = new MemoryStream(data, index, count, false))
+			using (ZipHelperStream helperStream = new ZipHelperStream(ms))
+			{
+				// bit 0           if set, modification time is present
+				// bit 1           if set, access time is present
+				// bit 2           if set, creation time is present
+
+				_flags = (Flags)helperStream.ReadByte();
+				if (((_flags & Flags.ModificationTime) != 0))
+				{
+					int iTime = helperStream.ReadLEInt();
+
+					_modificationTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc) +
+						new TimeSpan(0, 0, 0, iTime, 0);
+
+					// Central-header version is truncated after modification time
+					if (count <= 5) return;
+				}
+
+				if ((_flags & Flags.AccessTime) != 0)
+				{
+					int iTime = helperStream.ReadLEInt();
+
+					_lastAccessTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc) +
+						new TimeSpan(0, 0, 0, iTime, 0);
+				}
+
+				if ((_flags & Flags.CreateTime) != 0)
+				{
+					int iTime = helperStream.ReadLEInt();
+
+					_createTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc) +
+						new TimeSpan(0, 0, 0, iTime, 0);
+				}
+			}
+		}
+
+		/// <summary>
+		/// Get the binary data representing this instance.
+		/// </summary>
+		/// <returns>The raw binary data representing this instance.</returns>
+		public byte[] GetData()
+		{
+			using (MemoryStream ms = new MemoryStream())
+			using (ZipHelperStream helperStream = new ZipHelperStream(ms))
+			{
+				helperStream.IsStreamOwner = false;
+				helperStream.WriteByte((byte)_flags);     // Flags
+				if ((_flags & Flags.ModificationTime) != 0)
+				{
+					TimeSpan span = _modificationTime - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
+					var seconds = (int)span.TotalSeconds;
+					helperStream.WriteLEInt(seconds);
+				}
+				if ((_flags & Flags.AccessTime) != 0)
+				{
+					TimeSpan span = _lastAccessTime - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
+					var seconds = (int)span.TotalSeconds;
+					helperStream.WriteLEInt(seconds);
+				}
+				if ((_flags & Flags.CreateTime) != 0)
+				{
+					TimeSpan span = _createTime - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
+					var seconds = (int)span.TotalSeconds;
+					helperStream.WriteLEInt(seconds);
+				}
+				return ms.ToArray();
+			}
+		}
+
+		#endregion ITaggedData Members
+
+		/// <summary>
+		/// Test a <see cref="DateTime"> value to see if is valid and can be represented here.</see>
+		/// </summary>
+		/// <param name="value">The <see cref="DateTime">value</see> to test.</param>
+		/// <returns>Returns true if the value is valid and can be represented; false if not.</returns>
+		/// <remarks>The standard Unix time is a signed integer data type, directly encoding the Unix time number,
+		/// which is the number of seconds since 1970-01-01.
+		/// Being 32 bits means the values here cover a range of about 136 years.
+		/// The minimum representable time is 1901-12-13 20:45:52,
+		/// and the maximum representable time is 2038-01-19 03:14:07.
+		/// </remarks>
+		public static bool IsValidValue(DateTime value)
+		{
+			return ((value >= new DateTime(1901, 12, 13, 20, 45, 52)) ||
+					(value <= new DateTime(2038, 1, 19, 03, 14, 07)));
+		}
+
+		/// <summary>
+		/// Get /set the Modification Time
+		/// </summary>
+		/// <exception cref="ArgumentOutOfRangeException"></exception>
+		/// <seealso cref="IsValidValue"></seealso>
+		public DateTime ModificationTime
+		{
+			get { return _modificationTime; }
+			set
+			{
+				if (!IsValidValue(value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+
+				_flags |= Flags.ModificationTime;
+				_modificationTime = value;
+			}
+		}
+
+		/// <summary>
+		/// Get / set the Access Time
+		/// </summary>
+		/// <exception cref="ArgumentOutOfRangeException"></exception>
+		/// <seealso cref="IsValidValue"></seealso>
+		public DateTime AccessTime
+		{
+			get { return _lastAccessTime; }
+			set
+			{
+				if (!IsValidValue(value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+
+				_flags |= Flags.AccessTime;
+				_lastAccessTime = value;
+			}
+		}
+
+		/// <summary>
+		/// Get / Set the Create Time
+		/// </summary>
+		/// <exception cref="ArgumentOutOfRangeException"></exception>
+		/// <seealso cref="IsValidValue"></seealso>
+		public DateTime CreateTime
+		{
+			get { return _createTime; }
+			set
+			{
+				if (!IsValidValue(value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+
+				_flags |= Flags.CreateTime;
+				_createTime = value;
+			}
+		}
+
+		/// <summary>
+		/// Get/set the <see cref="Flags">values</see> to include.
+		/// </summary>
+		public Flags Include
+		{
+			get { return _flags; }
+			set { _flags = value; }
+		}
+
+		#region Instance Fields
+
+		private Flags _flags;
+		private DateTime _modificationTime = new DateTime(1970, 1, 1);
+		private DateTime _lastAccessTime = new DateTime(1970, 1, 1);
+		private DateTime _createTime = new DateTime(1970, 1, 1);
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// Class handling NT date time values.
+	/// </summary>
+	public class NTTaggedData : ITaggedData
+	{
+		/// <summary>
+		/// Get the ID for this tagged data value.
+		/// </summary>
+		public short TagID
+		{
+			get { return 10; }
+		}
+
+		/// <summary>
+		/// Set the data from the raw values provided.
+		/// </summary>
+		/// <param name="data">The raw data to extract values from.</param>
+		/// <param name="index">The index to start extracting values from.</param>
+		/// <param name="count">The number of bytes available.</param>
+		public void SetData(byte[] data, int index, int count)
+		{
+			using (MemoryStream ms = new MemoryStream(data, index, count, false))
+			using (ZipHelperStream helperStream = new ZipHelperStream(ms))
+			{
+				helperStream.ReadLEInt(); // Reserved
+				while (helperStream.Position < helperStream.Length)
+				{
+					int ntfsTag = helperStream.ReadLEShort();
+					int ntfsLength = helperStream.ReadLEShort();
+					if (ntfsTag == 1)
+					{
+						if (ntfsLength >= 24)
+						{
+							long lastModificationTicks = helperStream.ReadLELong();
+							_lastModificationTime = DateTime.FromFileTimeUtc(lastModificationTicks);
+
+							long lastAccessTicks = helperStream.ReadLELong();
+							_lastAccessTime = DateTime.FromFileTimeUtc(lastAccessTicks);
+
+							long createTimeTicks = helperStream.ReadLELong();
+							_createTime = DateTime.FromFileTimeUtc(createTimeTicks);
+						}
+						break;
+					}
+					else
+					{
+						// An unknown NTFS tag so simply skip it.
+						helperStream.Seek(ntfsLength, SeekOrigin.Current);
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// Get the binary data representing this instance.
+		/// </summary>
+		/// <returns>The raw binary data representing this instance.</returns>
+		public byte[] GetData()
+		{
+			using (MemoryStream ms = new MemoryStream())
+			using (ZipHelperStream helperStream = new ZipHelperStream(ms))
+			{
+				helperStream.IsStreamOwner = false;
+				helperStream.WriteLEInt(0);       // Reserved
+				helperStream.WriteLEShort(1);     // Tag
+				helperStream.WriteLEShort(24);    // Length = 3 x 8.
+				helperStream.WriteLELong(_lastModificationTime.ToFileTimeUtc());
+				helperStream.WriteLELong(_lastAccessTime.ToFileTimeUtc());
+				helperStream.WriteLELong(_createTime.ToFileTimeUtc());
+				return ms.ToArray();
+			}
+		}
+
+		/// <summary>
+		/// Test a <see cref="DateTime"> valuie to see if is valid and can be represented here.</see>
+		/// </summary>
+		/// <param name="value">The <see cref="DateTime">value</see> to test.</param>
+		/// <returns>Returns true if the value is valid and can be represented; false if not.</returns>
+		/// <remarks>
+		/// NTFS filetimes are 64-bit unsigned integers, stored in Intel
+		/// (least significant byte first) byte order. They determine the
+		/// number of 1.0E-07 seconds (1/10th microseconds!) past WinNT "epoch",
+		/// which is "01-Jan-1601 00:00:00 UTC". 28 May 60056 is the upper limit
+		/// </remarks>
+		public static bool IsValidValue(DateTime value)
+		{
+			bool result = true;
+			try
+			{
+				value.ToFileTimeUtc();
+			}
+			catch
+			{
+				result = false;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Get/set the <see cref="DateTime">last modification time</see>.
+		/// </summary>
+		public DateTime LastModificationTime
+		{
+			get { return _lastModificationTime; }
+			set
+			{
+				if (!IsValidValue(value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+				_lastModificationTime = value;
+			}
+		}
+
+		/// <summary>
+		/// Get /set the <see cref="DateTime">create time</see>
+		/// </summary>
+		public DateTime CreateTime
+		{
+			get { return _createTime; }
+			set
+			{
+				if (!IsValidValue(value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+				_createTime = value;
+			}
+		}
+
+		/// <summary>
+		/// Get /set the <see cref="DateTime">last access time</see>.
+		/// </summary>
+		public DateTime LastAccessTime
+		{
+			get { return _lastAccessTime; }
+			set
+			{
+				if (!IsValidValue(value))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+				_lastAccessTime = value;
+			}
+		}
+
+		#region Instance Fields
+
+		private DateTime _lastAccessTime = DateTime.FromFileTimeUtc(0);
+		private DateTime _lastModificationTime = DateTime.FromFileTimeUtc(0);
+		private DateTime _createTime = DateTime.FromFileTimeUtc(0);
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// A factory that creates <see cref="ITaggedData">tagged data</see> instances.
+	/// </summary>
+	internal interface ITaggedDataFactory
+	{
+		/// <summary>
+		/// Get data for a specific tag value.
+		/// </summary>
+		/// <param name="tag">The tag ID to find.</param>
+		/// <param name="data">The data to search.</param>
+		/// <param name="offset">The offset to begin extracting data from.</param>
+		/// <param name="count">The number of bytes to extract.</param>
+		/// <returns>The located <see cref="ITaggedData">value found</see>, or null if not found.</returns>
+		ITaggedData Create(short tag, byte[] data, int offset, int count);
+	}
+
+	///
+	/// <summary>
+	/// A class to handle the extra data field for Zip entries
+	/// </summary>
+	/// <remarks>
+	/// Extra data contains 0 or more values each prefixed by a header tag and length.
+	/// They contain zero or more bytes of actual data.
+	/// The data is held internally using a copy on write strategy.  This is more efficient but
+	/// means that for extra data created by passing in data can have the values modified by the caller
+	/// in some circumstances.
+	/// </remarks>
+	sealed public class ZipExtraData : IDisposable
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise a default instance.
+		/// </summary>
+		public ZipExtraData()
+		{
+			Clear();
+		}
+
+		/// <summary>
+		/// Initialise with known extra data.
+		/// </summary>
+		/// <param name="data">The extra data.</param>
+		public ZipExtraData(byte[] data)
+		{
+			if (data == null)
+			{
+				_data = new byte[0];
+			}
+			else
+			{
+				_data = data;
+			}
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Get the raw extra data value
+		/// </summary>
+		/// <returns>Returns the raw byte[] extra data this instance represents.</returns>
+		public byte[] GetEntryData()
+		{
+			if (Length > ushort.MaxValue)
+			{
+				throw new ZipException("Data exceeds maximum length");
+			}
+
+			return (byte[])_data.Clone();
+		}
+
+		/// <summary>
+		/// Clear the stored data.
+		/// </summary>
+		public void Clear()
+		{
+			if ((_data == null) || (_data.Length != 0))
+			{
+				_data = new byte[0];
+			}
+		}
+
+		/// <summary>
+		/// Gets the current extra data length.
+		/// </summary>
+		public int Length
+		{
+			get { return _data.Length; }
+		}
+
+		/// <summary>
+		/// Get a read-only <see cref="Stream"/> for the associated tag.
+		/// </summary>
+		/// <param name="tag">The tag to locate data for.</param>
+		/// <returns>Returns a <see cref="Stream"/> containing tag data or null if no tag was found.</returns>
+		public Stream GetStreamForTag(int tag)
+		{
+			Stream result = null;
+			if (Find(tag))
+			{
+				result = new MemoryStream(_data, _index, _readValueLength, false);
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Get the <see cref="ITaggedData">tagged data</see> for a tag.
+		/// </summary>
+		/// <typeparam name="T">The tag to search for.</typeparam>
+		/// <returns>Returns a <see cref="ITaggedData">tagged value</see> or null if none found.</returns>
+		public T GetData<T>()
+			where T : class, ITaggedData, new()
+		{
+			T result = new T();
+			if (Find(result.TagID))
+			{
+				result.SetData(_data, _readValueStart, _readValueLength);
+				return result;
+			}
+			else return null;
+		}
+
+		/// <summary>
+		/// Get the length of the last value found by <see cref="Find"/>
+		/// </summary>
+		/// <remarks>This is only valid if <see cref="Find"/> has previously returned true.</remarks>
+		public int ValueLength
+		{
+			get { return _readValueLength; }
+		}
+
+		/// <summary>
+		/// Get the index for the current read value.
+		/// </summary>
+		/// <remarks>This is only valid if <see cref="Find"/> has previously returned true.
+		/// Initially the result will be the index of the first byte of actual data.  The value is updated after calls to
+		/// <see cref="ReadInt"/>, <see cref="ReadShort"/> and <see cref="ReadLong"/>. </remarks>
+		public int CurrentReadIndex
+		{
+			get { return _index; }
+		}
+
+		/// <summary>
+		/// Get the number of bytes remaining to be read for the current value;
+		/// </summary>
+		public int UnreadCount
+		{
+			get
+			{
+				if ((_readValueStart > _data.Length) ||
+					(_readValueStart < 4))
+				{
+					throw new ZipException("Find must be called before calling a Read method");
+				}
+
+				return _readValueStart + _readValueLength - _index;
+			}
+		}
+
+		/// <summary>
+		/// Find an extra data value
+		/// </summary>
+		/// <param name="headerID">The identifier for the value to find.</param>
+		/// <returns>Returns true if the value was found; false otherwise.</returns>
+		public bool Find(int headerID)
+		{
+			_readValueStart = _data.Length;
+			_readValueLength = 0;
+			_index = 0;
+
+			int localLength = _readValueStart;
+			int localTag = headerID - 1;
+
+			// Trailing bytes that cant make up an entry (as there arent enough
+			// bytes for a tag and length) are ignored!
+			while ((localTag != headerID) && (_index < _data.Length - 3))
+			{
+				localTag = ReadShortInternal();
+				localLength = ReadShortInternal();
+				if (localTag != headerID)
+				{
+					_index += localLength;
+				}
+			}
+
+			bool result = (localTag == headerID) && ((_index + localLength) <= _data.Length);
+
+			if (result)
+			{
+				_readValueStart = _index;
+				_readValueLength = localLength;
+			}
+
+			return result;
+		}
+
+		/// <summary>
+		/// Add a new entry to extra data.
+		/// </summary>
+		/// <param name="taggedData">The <see cref="ITaggedData"/> value to add.</param>
+		public void AddEntry(ITaggedData taggedData)
+		{
+			if (taggedData == null)
+			{
+				throw new ArgumentNullException(nameof(taggedData));
+			}
+			AddEntry(taggedData.TagID, taggedData.GetData());
+		}
+
+		/// <summary>
+		/// Add a new entry to extra data
+		/// </summary>
+		/// <param name="headerID">The ID for this entry.</param>
+		/// <param name="fieldData">The data to add.</param>
+		/// <remarks>If the ID already exists its contents are replaced.</remarks>
+		public void AddEntry(int headerID, byte[] fieldData)
+		{
+			if ((headerID > ushort.MaxValue) || (headerID < 0))
+			{
+				throw new ArgumentOutOfRangeException(nameof(headerID));
+			}
+
+			int addLength = (fieldData == null) ? 0 : fieldData.Length;
+
+			if (addLength > ushort.MaxValue)
+			{
+				throw new ArgumentOutOfRangeException(nameof(fieldData), "exceeds maximum length");
+			}
+
+			// Test for new length before adjusting data.
+			int newLength = _data.Length + addLength + 4;
+
+			if (Find(headerID))
+			{
+				newLength -= (ValueLength + 4);
+			}
+
+			if (newLength > ushort.MaxValue)
+			{
+				throw new ZipException("Data exceeds maximum length");
+			}
+
+			Delete(headerID);
+
+			byte[] newData = new byte[newLength];
+			_data.CopyTo(newData, 0);
+			int index = _data.Length;
+			_data = newData;
+			SetShort(ref index, headerID);
+			SetShort(ref index, addLength);
+			if (fieldData != null)
+			{
+				fieldData.CopyTo(newData, index);
+			}
+		}
+
+		/// <summary>
+		/// Start adding a new entry.
+		/// </summary>
+		/// <remarks>Add data using <see cref="AddData(byte[])"/>, <see cref="AddLeShort"/>, <see cref="AddLeInt"/>, or <see cref="AddLeLong"/>.
+		/// The new entry is completed and actually added by calling <see cref="AddNewEntry"/></remarks>
+		/// <seealso cref="AddEntry(ITaggedData)"/>
+		public void StartNewEntry()
+		{
+			_newEntry = new MemoryStream();
+		}
+
+		/// <summary>
+		/// Add entry data added since <see cref="StartNewEntry"/> using the ID passed.
+		/// </summary>
+		/// <param name="headerID">The identifier to use for this entry.</param>
+		public void AddNewEntry(int headerID)
+		{
+			byte[] newData = _newEntry.ToArray();
+			_newEntry = null;
+			AddEntry(headerID, newData);
+		}
+
+		/// <summary>
+		/// Add a byte of data to the pending new entry.
+		/// </summary>
+		/// <param name="data">The byte to add.</param>
+		/// <seealso cref="StartNewEntry"/>
+		public void AddData(byte data)
+		{
+			_newEntry.WriteByte(data);
+		}
+
+		/// <summary>
+		/// Add data to a pending new entry.
+		/// </summary>
+		/// <param name="data">The data to add.</param>
+		/// <seealso cref="StartNewEntry"/>
+		public void AddData(byte[] data)
+		{
+			if (data == null)
+			{
+				throw new ArgumentNullException(nameof(data));
+			}
+
+			_newEntry.Write(data, 0, data.Length);
+		}
+
+		/// <summary>
+		/// Add a short value in little endian order to the pending new entry.
+		/// </summary>
+		/// <param name="toAdd">The data to add.</param>
+		/// <seealso cref="StartNewEntry"/>
+		public void AddLeShort(int toAdd)
+		{
+			unchecked
+			{
+				_newEntry.WriteByte((byte)toAdd);
+				_newEntry.WriteByte((byte)(toAdd >> 8));
+			}
+		}
+
+		/// <summary>
+		/// Add an integer value in little endian order to the pending new entry.
+		/// </summary>
+		/// <param name="toAdd">The data to add.</param>
+		/// <seealso cref="StartNewEntry"/>
+		public void AddLeInt(int toAdd)
+		{
+			unchecked
+			{
+				AddLeShort((short)toAdd);
+				AddLeShort((short)(toAdd >> 16));
+			}
+		}
+
+		/// <summary>
+		/// Add a long value in little endian order to the pending new entry.
+		/// </summary>
+		/// <param name="toAdd">The data to add.</param>
+		/// <seealso cref="StartNewEntry"/>
+		public void AddLeLong(long toAdd)
+		{
+			unchecked
+			{
+				AddLeInt((int)(toAdd & 0xffffffff));
+				AddLeInt((int)(toAdd >> 32));
+			}
+		}
+
+		/// <summary>
+		/// Delete an extra data field.
+		/// </summary>
+		/// <param name="headerID">The identifier of the field to delete.</param>
+		/// <returns>Returns true if the field was found and deleted.</returns>
+		public bool Delete(int headerID)
+		{
+			bool result = false;
+
+			if (Find(headerID))
+			{
+				result = true;
+				int trueStart = _readValueStart - 4;
+
+				byte[] newData = new byte[_data.Length - (ValueLength + 4)];
+				Array.Copy(_data, 0, newData, 0, trueStart);
+
+				int trueEnd = trueStart + ValueLength + 4;
+				Array.Copy(_data, trueEnd, newData, trueStart, _data.Length - trueEnd);
+				_data = newData;
+			}
+			return result;
+		}
+
+		#region Reading Support
+
+		/// <summary>
+		/// Read a long in little endian form from the last <see cref="Find">found</see> data value
+		/// </summary>
+		/// <returns>Returns the long value read.</returns>
+		public long ReadLong()
+		{
+			ReadCheck(8);
+			return (ReadInt() & 0xffffffff) | (((long)ReadInt()) << 32);
+		}
+
+		/// <summary>
+		/// Read an integer in little endian form from the last <see cref="Find">found</see> data value.
+		/// </summary>
+		/// <returns>Returns the integer read.</returns>
+		public int ReadInt()
+		{
+			ReadCheck(4);
+
+			int result = _data[_index] + (_data[_index + 1] << 8) +
+				(_data[_index + 2] << 16) + (_data[_index + 3] << 24);
+			_index += 4;
+			return result;
+		}
+
+		/// <summary>
+		/// Read a short value in little endian form from the last <see cref="Find">found</see> data value.
+		/// </summary>
+		/// <returns>Returns the short value read.</returns>
+		public int ReadShort()
+		{
+			ReadCheck(2);
+			int result = _data[_index] + (_data[_index + 1] << 8);
+			_index += 2;
+			return result;
+		}
+
+		/// <summary>
+		/// Read a byte from an extra data
+		/// </summary>
+		/// <returns>The byte value read or -1 if the end of data has been reached.</returns>
+		public int ReadByte()
+		{
+			int result = -1;
+			if ((_index < _data.Length) && (_readValueStart + _readValueLength > _index))
+			{
+				result = _data[_index];
+				_index += 1;
+			}
+			return result;
+		}
+
+		/// <summary>
+		/// Skip data during reading.
+		/// </summary>
+		/// <param name="amount">The number of bytes to skip.</param>
+		public void Skip(int amount)
+		{
+			ReadCheck(amount);
+			_index += amount;
+		}
+
+		private void ReadCheck(int length)
+		{
+			if ((_readValueStart > _data.Length) ||
+				(_readValueStart < 4))
+			{
+				throw new ZipException("Find must be called before calling a Read method");
+			}
+
+			if (_index > _readValueStart + _readValueLength - length)
+			{
+				throw new ZipException("End of extra data");
+			}
+
+			if (_index + length < 4)
+			{
+				throw new ZipException("Cannot read before start of tag");
+			}
+		}
+
+		/// <summary>
+		/// Internal form of <see cref="ReadShort"/> that reads data at any location.
+		/// </summary>
+		/// <returns>Returns the short value read.</returns>
+		private int ReadShortInternal()
+		{
+			if (_index > _data.Length - 2)
+			{
+				throw new ZipException("End of extra data");
+			}
+
+			int result = _data[_index] + (_data[_index + 1] << 8);
+			_index += 2;
+			return result;
+		}
+
+		private void SetShort(ref int index, int source)
+		{
+			_data[index] = (byte)source;
+			_data[index + 1] = (byte)(source >> 8);
+			index += 2;
+		}
+
+		#endregion Reading Support
+
+		#region IDisposable Members
+
+		/// <summary>
+		/// Dispose of this instance.
+		/// </summary>
+		public void Dispose()
+		{
+			if (_newEntry != null)
+			{
+				_newEntry.Dispose();
+			}
+		}
+
+		#endregion IDisposable Members
+
+		#region Instance Fields
+
+		private int _index;
+		private int _readValueStart;
+		private int _readValueLength;
+
+		private MemoryStream _newEntry;
+		private byte[] _data;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipHelperStream.cs

@@ -0,0 +1,629 @@
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// Holds data pertinent to a data descriptor.
+	/// </summary>
+	public class DescriptorData
+	{
+		/// <summary>
+		/// Get /set the compressed size of data.
+		/// </summary>
+		public long CompressedSize
+		{
+			get { return compressedSize; }
+			set { compressedSize = value; }
+		}
+
+		/// <summary>
+		/// Get / set the uncompressed size of data
+		/// </summary>
+		public long Size
+		{
+			get { return size; }
+			set { size = value; }
+		}
+
+		/// <summary>
+		/// Get /set the crc value.
+		/// </summary>
+		public long Crc
+		{
+			get { return crc; }
+			set { crc = (value & 0xffffffff); }
+		}
+
+		#region Instance Fields
+
+		private long size;
+		private long compressedSize;
+		private long crc;
+
+		#endregion Instance Fields
+	}
+
+	internal class EntryPatchData
+	{
+		public long SizePatchOffset
+		{
+			get { return sizePatchOffset_; }
+			set { sizePatchOffset_ = value; }
+		}
+
+		public long CrcPatchOffset
+		{
+			get { return crcPatchOffset_; }
+			set { crcPatchOffset_ = value; }
+		}
+
+		#region Instance Fields
+
+		private long sizePatchOffset_;
+		private long crcPatchOffset_;
+
+		#endregion Instance Fields
+	}
+
+	/// <summary>
+	/// This class assists with writing/reading from Zip files.
+	/// </summary>
+	internal class ZipHelperStream : Stream
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialise an instance of this class.
+		/// </summary>
+		/// <param name="name">The name of the file to open.</param>
+		public ZipHelperStream(string name)
+		{
+			stream_ = new FileStream(name, FileMode.Open, FileAccess.ReadWrite);
+			isOwner_ = true;
+		}
+
+		/// <summary>
+		/// Initialise a new instance of <see cref="ZipHelperStream"/>.
+		/// </summary>
+		/// <param name="stream">The stream to use.</param>
+		public ZipHelperStream(Stream stream)
+		{
+			stream_ = stream;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Get / set a value indicating wether the the underlying stream is owned or not.
+		/// </summary>
+		/// <remarks>If the stream is owned it is closed when this instance is closed.</remarks>
+		public bool IsStreamOwner
+		{
+			get { return isOwner_; }
+			set { isOwner_ = value; }
+		}
+
+		#region Base Stream Methods
+
+		public override bool CanRead
+		{
+			get { return stream_.CanRead; }
+		}
+
+		public override bool CanSeek
+		{
+			get { return stream_.CanSeek; }
+		}
+
+		public override bool CanTimeout
+		{
+			get { return stream_.CanTimeout; }
+		}
+
+		public override long Length
+		{
+			get { return stream_.Length; }
+		}
+
+		public override long Position
+		{
+			get { return stream_.Position; }
+			set { stream_.Position = value; }
+		}
+
+		public override bool CanWrite
+		{
+			get { return stream_.CanWrite; }
+		}
+
+		public override void Flush()
+		{
+			stream_.Flush();
+		}
+
+		public override long Seek(long offset, SeekOrigin origin)
+		{
+			return stream_.Seek(offset, origin);
+		}
+
+		public override void SetLength(long value)
+		{
+			stream_.SetLength(value);
+		}
+
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			return stream_.Read(buffer, offset, count);
+		}
+
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			stream_.Write(buffer, offset, count);
+		}
+
+		/// <summary>
+		/// Close the stream.
+		/// </summary>
+		/// <remarks>
+		/// The underlying stream is closed only if <see cref="IsStreamOwner"/> is true.
+		/// </remarks>
+		protected override void Dispose(bool disposing)
+		{
+			Stream toClose = stream_;
+			stream_ = null;
+			if (isOwner_ && (toClose != null))
+			{
+				isOwner_ = false;
+				toClose.Dispose();
+			}
+		}
+
+		#endregion Base Stream Methods
+
+		// Write the local file header
+		// TODO: ZipHelperStream.WriteLocalHeader is not yet used and needs checking for ZipFile and ZipOuptutStream usage
+		private void WriteLocalHeader(ZipEntry entry, EntryPatchData patchData)
+		{
+			CompressionMethod method = entry.CompressionMethod;
+			bool headerInfoAvailable = true; // How to get this?
+			bool patchEntryHeader = false;
+
+			WriteLEInt(ZipConstants.LocalHeaderSignature);
+
+			WriteLEShort(entry.Version);
+			WriteLEShort(entry.Flags);
+			WriteLEShort((byte)method);
+			WriteLEInt((int)entry.DosTime);
+
+			if (headerInfoAvailable == true)
+			{
+				WriteLEInt((int)entry.Crc);
+				if (entry.LocalHeaderRequiresZip64)
+				{
+					WriteLEInt(-1);
+					WriteLEInt(-1);
+				}
+				else
+				{
+					WriteLEInt(entry.IsCrypted ? (int)entry.CompressedSize + ZipConstants.CryptoHeaderSize : (int)entry.CompressedSize);
+					WriteLEInt((int)entry.Size);
+				}
+			}
+			else
+			{
+				if (patchData != null)
+				{
+					patchData.CrcPatchOffset = stream_.Position;
+				}
+				WriteLEInt(0);  // Crc
+
+				if (patchData != null)
+				{
+					patchData.SizePatchOffset = stream_.Position;
+				}
+
+				// For local header both sizes appear in Zip64 Extended Information
+				if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
+				{
+					WriteLEInt(-1);
+					WriteLEInt(-1);
+				}
+				else
+				{
+					WriteLEInt(0);  // Compressed size
+					WriteLEInt(0);  // Uncompressed size
+				}
+			}
+
+			byte[] name = ZipStrings.ConvertToArray(entry.Flags, entry.Name);
+
+			if (name.Length > 0xFFFF)
+			{
+				throw new ZipException("Entry name too long.");
+			}
+
+			var ed = new ZipExtraData(entry.ExtraData);
+
+			if (entry.LocalHeaderRequiresZip64 && (headerInfoAvailable || patchEntryHeader))
+			{
+				ed.StartNewEntry();
+				if (headerInfoAvailable)
+				{
+					ed.AddLeLong(entry.Size);
+					ed.AddLeLong(entry.CompressedSize);
+				}
+				else
+				{
+					ed.AddLeLong(-1);
+					ed.AddLeLong(-1);
+				}
+				ed.AddNewEntry(1);
+
+				if (!ed.Find(1))
+				{
+					throw new ZipException("Internal error cant find extra data");
+				}
+
+				if (patchData != null)
+				{
+					patchData.SizePatchOffset = ed.CurrentReadIndex;
+				}
+			}
+			else
+			{
+				ed.Delete(1);
+			}
+
+			byte[] extra = ed.GetEntryData();
+
+			WriteLEShort(name.Length);
+			WriteLEShort(extra.Length);
+
+			if (name.Length > 0)
+			{
+				stream_.Write(name, 0, name.Length);
+			}
+
+			if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
+			{
+				patchData.SizePatchOffset += stream_.Position;
+			}
+
+			if (extra.Length > 0)
+			{
+				stream_.Write(extra, 0, extra.Length);
+			}
+		}
+
+		/// <summary>
+		/// Locates a block with the desired <paramref name="signature"/>.
+		/// </summary>
+		/// <param name="signature">The signature to find.</param>
+		/// <param name="endLocation">Location, marking the end of block.</param>
+		/// <param name="minimumBlockSize">Minimum size of the block.</param>
+		/// <param name="maximumVariableData">The maximum variable data.</param>
+		/// <returns>Eeturns the offset of the first byte after the signature; -1 if not found</returns>
+		public long LocateBlockWithSignature(int signature, long endLocation, int minimumBlockSize, int maximumVariableData)
+		{
+			long pos = endLocation - minimumBlockSize;
+			if (pos < 0)
+			{
+				return -1;
+			}
+
+			long giveUpMarker = Math.Max(pos - maximumVariableData, 0);
+
+			// TODO: This loop could be optimised for speed.
+			do
+			{
+				if (pos < giveUpMarker)
+				{
+					return -1;
+				}
+				Seek(pos--, SeekOrigin.Begin);
+			} while (ReadLEInt() != signature);
+
+			return Position;
+		}
+
+		/// <summary>
+		/// Write Zip64 end of central directory records (File header and locator).
+		/// </summary>
+		/// <param name="noOfEntries">The number of entries in the central directory.</param>
+		/// <param name="sizeEntries">The size of entries in the central directory.</param>
+		/// <param name="centralDirOffset">The offset of the dentral directory.</param>
+		public void WriteZip64EndOfCentralDirectory(long noOfEntries, long sizeEntries, long centralDirOffset)
+		{
+			long centralSignatureOffset = centralDirOffset + sizeEntries;
+			WriteLEInt(ZipConstants.Zip64CentralFileHeaderSignature);
+			WriteLELong(44);    // Size of this record (total size of remaining fields in header or full size - 12)
+			WriteLEShort(ZipConstants.VersionMadeBy);   // Version made by
+			WriteLEShort(ZipConstants.VersionZip64);   // Version to extract
+			WriteLEInt(0);      // Number of this disk
+			WriteLEInt(0);      // number of the disk with the start of the central directory
+			WriteLELong(noOfEntries);       // No of entries on this disk
+			WriteLELong(noOfEntries);       // Total No of entries in central directory
+			WriteLELong(sizeEntries);       // Size of the central directory
+			WriteLELong(centralDirOffset);  // offset of start of central directory
+											// zip64 extensible data sector not catered for here (variable size)
+
+			// Write the Zip64 end of central directory locator
+			WriteLEInt(ZipConstants.Zip64CentralDirLocatorSignature);
+
+			// no of the disk with the start of the zip64 end of central directory
+			WriteLEInt(0);
+
+			// relative offset of the zip64 end of central directory record
+			WriteLELong(centralSignatureOffset);
+
+			// total number of disks
+			WriteLEInt(1);
+		}
+
+		/// <summary>
+		/// Write the required records to end the central directory.
+		/// </summary>
+		/// <param name="noOfEntries">The number of entries in the directory.</param>
+		/// <param name="sizeEntries">The size of the entries in the directory.</param>
+		/// <param name="startOfCentralDirectory">The start of the central directory.</param>
+		/// <param name="comment">The archive comment.  (This can be null).</param>
+		public void WriteEndOfCentralDirectory(long noOfEntries, long sizeEntries,
+			long startOfCentralDirectory, byte[] comment)
+		{
+			if ((noOfEntries >= 0xffff) ||
+				(startOfCentralDirectory >= 0xffffffff) ||
+				(sizeEntries >= 0xffffffff))
+			{
+				WriteZip64EndOfCentralDirectory(noOfEntries, sizeEntries, startOfCentralDirectory);
+			}
+
+			WriteLEInt(ZipConstants.EndOfCentralDirectorySignature);
+
+			// TODO: ZipFile Multi disk handling not done
+			WriteLEShort(0);                    // number of this disk
+			WriteLEShort(0);                    // no of disk with start of central dir
+
+			// Number of entries
+			if (noOfEntries >= 0xffff)
+			{
+				WriteLEUshort(0xffff);  // Zip64 marker
+				WriteLEUshort(0xffff);
+			}
+			else
+			{
+				WriteLEShort((short)noOfEntries);          // entries in central dir for this disk
+				WriteLEShort((short)noOfEntries);          // total entries in central directory
+			}
+
+			// Size of the central directory
+			if (sizeEntries >= 0xffffffff)
+			{
+				WriteLEUint(0xffffffff);    // Zip64 marker
+			}
+			else
+			{
+				WriteLEInt((int)sizeEntries);
+			}
+
+			// offset of start of central directory
+			if (startOfCentralDirectory >= 0xffffffff)
+			{
+				WriteLEUint(0xffffffff);    // Zip64 marker
+			}
+			else
+			{
+				WriteLEInt((int)startOfCentralDirectory);
+			}
+
+			int commentLength = (comment != null) ? comment.Length : 0;
+
+			if (commentLength > 0xffff)
+			{
+				throw new ZipException(string.Format("Comment length({0}) is too long can only be 64K", commentLength));
+			}
+
+			WriteLEShort(commentLength);
+
+			if (commentLength > 0)
+			{
+				Write(comment, 0, comment.Length);
+			}
+		}
+
+		#region LE value reading/writing
+
+		/// <summary>
+		/// Read an unsigned short in little endian byte order.
+		/// </summary>
+		/// <returns>Returns the value read.</returns>
+		/// <exception cref="IOException">
+		/// An i/o error occurs.
+		/// </exception>
+		/// <exception cref="EndOfStreamException">
+		/// The file ends prematurely
+		/// </exception>
+		public int ReadLEShort()
+		{
+			int byteValue1 = stream_.ReadByte();
+
+			if (byteValue1 < 0)
+			{
+				throw new EndOfStreamException();
+			}
+
+			int byteValue2 = stream_.ReadByte();
+			if (byteValue2 < 0)
+			{
+				throw new EndOfStreamException();
+			}
+
+			return byteValue1 | (byteValue2 << 8);
+		}
+
+		/// <summary>
+		/// Read an int in little endian byte order.
+		/// </summary>
+		/// <returns>Returns the value read.</returns>
+		/// <exception cref="IOException">
+		/// An i/o error occurs.
+		/// </exception>
+		/// <exception cref="System.IO.EndOfStreamException">
+		/// The file ends prematurely
+		/// </exception>
+		public int ReadLEInt()
+		{
+			return ReadLEShort() | (ReadLEShort() << 16);
+		}
+
+		/// <summary>
+		/// Read a long in little endian byte order.
+		/// </summary>
+		/// <returns>The value read.</returns>
+		public long ReadLELong()
+		{
+			return (uint)ReadLEInt() | ((long)ReadLEInt() << 32);
+		}
+
+		/// <summary>
+		/// Write an unsigned short in little endian byte order.
+		/// </summary>
+		/// <param name="value">The value to write.</param>
+		public void WriteLEShort(int value)
+		{
+			stream_.WriteByte((byte)(value & 0xff));
+			stream_.WriteByte((byte)((value >> 8) & 0xff));
+		}
+
+		/// <summary>
+		/// Write a ushort in little endian byte order.
+		/// </summary>
+		/// <param name="value">The value to write.</param>
+		public void WriteLEUshort(ushort value)
+		{
+			stream_.WriteByte((byte)(value & 0xff));
+			stream_.WriteByte((byte)(value >> 8));
+		}
+
+		/// <summary>
+		/// Write an int in little endian byte order.
+		/// </summary>
+		/// <param name="value">The value to write.</param>
+		public void WriteLEInt(int value)
+		{
+			WriteLEShort(value);
+			WriteLEShort(value >> 16);
+		}
+
+		/// <summary>
+		/// Write a uint in little endian byte order.
+		/// </summary>
+		/// <param name="value">The value to write.</param>
+		public void WriteLEUint(uint value)
+		{
+			WriteLEUshort((ushort)(value & 0xffff));
+			WriteLEUshort((ushort)(value >> 16));
+		}
+
+		/// <summary>
+		/// Write a long in little endian byte order.
+		/// </summary>
+		/// <param name="value">The value to write.</param>
+		public void WriteLELong(long value)
+		{
+			WriteLEInt((int)value);
+			WriteLEInt((int)(value >> 32));
+		}
+
+		/// <summary>
+		/// Write a ulong in little endian byte order.
+		/// </summary>
+		/// <param name="value">The value to write.</param>
+		public void WriteLEUlong(ulong value)
+		{
+			WriteLEUint((uint)(value & 0xffffffff));
+			WriteLEUint((uint)(value >> 32));
+		}
+
+		#endregion LE value reading/writing
+
+		/// <summary>
+		/// Write a data descriptor.
+		/// </summary>
+		/// <param name="entry">The entry to write a descriptor for.</param>
+		/// <returns>Returns the number of descriptor bytes written.</returns>
+		public int WriteDataDescriptor(ZipEntry entry)
+		{
+			if (entry == null)
+			{
+				throw new ArgumentNullException(nameof(entry));
+			}
+
+			int result = 0;
+
+			// Add data descriptor if flagged as required
+			if ((entry.Flags & (int)GeneralBitFlags.Descriptor) != 0)
+			{
+				// The signature is not PKZIP originally but is now described as optional
+				// in the PKZIP Appnote documenting trhe format.
+				WriteLEInt(ZipConstants.DataDescriptorSignature);
+				WriteLEInt(unchecked((int)(entry.Crc)));
+
+				result += 8;
+
+				if (entry.LocalHeaderRequiresZip64)
+				{
+					WriteLELong(entry.CompressedSize);
+					WriteLELong(entry.Size);
+					result += 16;
+				}
+				else
+				{
+					WriteLEInt((int)entry.CompressedSize);
+					WriteLEInt((int)entry.Size);
+					result += 8;
+				}
+			}
+
+			return result;
+		}
+
+		/// <summary>
+		/// Read data descriptor at the end of compressed data.
+		/// </summary>
+		/// <param name="zip64">if set to <c>true</c> [zip64].</param>
+		/// <param name="data">The data to fill in.</param>
+		/// <returns>Returns the number of bytes read in the descriptor.</returns>
+		public void ReadDataDescriptor(bool zip64, DescriptorData data)
+		{
+			int intValue = ReadLEInt();
+
+			// In theory this may not be a descriptor according to PKZIP appnote.
+			// In practise its always there.
+			if (intValue != ZipConstants.DataDescriptorSignature)
+			{
+				throw new ZipException("Data descriptor signature not found");
+			}
+
+			data.Crc = ReadLEInt();
+
+			if (zip64)
+			{
+				data.CompressedSize = ReadLELong();
+				data.Size = ReadLELong();
+			}
+			else
+			{
+				data.CompressedSize = ReadLEInt();
+				data.Size = ReadLEInt();
+			}
+		}
+
+		#region Instance Fields
+
+		private bool isOwner_;
+		private Stream stream_;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipInputStream.cs

@@ -0,0 +1,694 @@
+using ICSharpCode.SharpZipLib.Checksum;
+using ICSharpCode.SharpZipLib.Encryption;
+using ICSharpCode.SharpZipLib.Zip.Compression;
+using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
+using System;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// This is an InflaterInputStream that reads the files baseInputStream an zip archive
+	/// one after another.  It has a special method to get the zip entry of
+	/// the next file.  The zip entry contains information about the file name
+	/// size, compressed size, Crc, etc.
+	/// It includes support for Stored and Deflated entries.
+	/// <br/>
+	/// <br/>Author of the original java version : Jochen Hoenicke
+	/// </summary>
+	///
+	/// <example> This sample shows how to read a zip file
+	/// <code lang="C#">
+	/// using System;
+	/// using System.Text;
+	/// using System.IO;
+	///
+	/// using ICSharpCode.SharpZipLib.Zip;
+	///
+	/// class MainClass
+	/// {
+	/// 	public static void Main(string[] args)
+	/// 	{
+	/// 		using ( ZipInputStream s = new ZipInputStream(File.OpenRead(args[0]))) {
+	///
+	/// 			ZipEntry theEntry;
+	/// 			const int size = 2048;
+	/// 			byte[] data = new byte[2048];
+	///
+	/// 			while ((theEntry = s.GetNextEntry()) != null) {
+	///                 if ( entry.IsFile ) {
+	/// 				    Console.Write("Show contents (y/n) ?");
+	/// 				    if (Console.ReadLine() == "y") {
+	/// 				    	while (true) {
+	/// 				    		size = s.Read(data, 0, data.Length);
+	/// 				    		if (size > 0) {
+	/// 				    			Console.Write(new ASCIIEncoding().GetString(data, 0, size));
+	/// 				    		} else {
+	/// 				    			break;
+	/// 				    		}
+	/// 				    	}
+	/// 				    }
+	/// 				}
+	/// 			}
+	/// 		}
+	/// 	}
+	/// }
+	/// </code>
+	/// </example>
+	public class ZipInputStream : InflaterInputStream
+	{
+		#region Instance Fields
+
+		/// <summary>
+		/// Delegate for reading bytes from a stream.
+		/// </summary>
+		private delegate int ReadDataHandler(byte[] b, int offset, int length);
+
+		/// <summary>
+		/// The current reader this instance.
+		/// </summary>
+		private ReadDataHandler internalReader;
+
+		private Crc32 crc = new Crc32();
+		private ZipEntry entry;
+
+		private long size;
+		private int method;
+		private int flags;
+		private string password;
+
+		#endregion Instance Fields
+
+		#region Constructors
+
+		/// <summary>
+		/// Creates a new Zip input stream, for reading a zip archive.
+		/// </summary>
+		/// <param name="baseInputStream">The underlying <see cref="Stream"/> providing data.</param>
+		public ZipInputStream(Stream baseInputStream)
+			: base(baseInputStream, new Inflater(true))
+		{
+			internalReader = new ReadDataHandler(ReadingNotAvailable);
+		}
+
+		/// <summary>
+		/// Creates a new Zip input stream, for reading a zip archive.
+		/// </summary>
+		/// <param name="baseInputStream">The underlying <see cref="Stream"/> providing data.</param>
+		/// <param name="bufferSize">Size of the buffer.</param>
+		public ZipInputStream(Stream baseInputStream, int bufferSize)
+			: base(baseInputStream, new Inflater(true), bufferSize)
+		{
+			internalReader = new ReadDataHandler(ReadingNotAvailable);
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Optional password used for encryption when non-null
+		/// </summary>
+		/// <value>A password for all encrypted <see cref="ZipEntry">entries </see> in this <see cref="ZipInputStream"/></value>
+		public string Password
+		{
+			get
+			{
+				return password;
+			}
+			set
+			{
+				password = value;
+			}
+		}
+
+		/// <summary>
+		/// Gets a value indicating if there is a current entry and it can be decompressed
+		/// </summary>
+		/// <remarks>
+		/// The entry can only be decompressed if the library supports the zip features required to extract it.
+		/// See the <see cref="ZipEntry.Version">ZipEntry Version</see> property for more details.
+		/// </remarks>
+		public bool CanDecompressEntry
+		{
+			get
+			{
+				return (entry != null) && entry.CanDecompress;
+			}
+		}
+
+		/// <summary>
+		/// Advances to the next entry in the archive
+		/// </summary>
+		/// <returns>
+		/// The next <see cref="ZipEntry">entry</see> in the archive or null if there are no more entries.
+		/// </returns>
+		/// <remarks>
+		/// If the previous entry is still open <see cref="CloseEntry">CloseEntry</see> is called.
+		/// </remarks>
+		/// <exception cref="InvalidOperationException">
+		/// Input stream is closed
+		/// </exception>
+		/// <exception cref="ZipException">
+		/// Password is not set, password is invalid, compression method is invalid,
+		/// version required to extract is not supported
+		/// </exception>
+		public ZipEntry GetNextEntry()
+		{
+			if (crc == null)
+			{
+				throw new InvalidOperationException("Closed.");
+			}
+
+			if (entry != null)
+			{
+				CloseEntry();
+			}
+
+			int header = inputBuffer.ReadLeInt();
+
+			if (header == ZipConstants.CentralHeaderSignature ||
+				header == ZipConstants.EndOfCentralDirectorySignature ||
+				header == ZipConstants.CentralHeaderDigitalSignature ||
+				header == ZipConstants.ArchiveExtraDataSignature ||
+				header == ZipConstants.Zip64CentralFileHeaderSignature)
+			{
+				// No more individual entries exist
+				Dispose();
+				return null;
+			}
+
+			// -jr- 07-Dec-2003 Ignore spanning temporary signatures if found
+			// Spanning signature is same as descriptor signature and is untested as yet.
+			if ((header == ZipConstants.SpanningTempSignature) || (header == ZipConstants.SpanningSignature))
+			{
+				header = inputBuffer.ReadLeInt();
+			}
+
+			if (header != ZipConstants.LocalHeaderSignature)
+			{
+				throw new ZipException("Wrong Local header signature: 0x" + String.Format("{0:X}", header));
+			}
+
+			var versionRequiredToExtract = (short)inputBuffer.ReadLeShort();
+
+			flags = inputBuffer.ReadLeShort();
+			method = inputBuffer.ReadLeShort();
+			var dostime = (uint)inputBuffer.ReadLeInt();
+			int crc2 = inputBuffer.ReadLeInt();
+			csize = inputBuffer.ReadLeInt();
+			size = inputBuffer.ReadLeInt();
+			int nameLen = inputBuffer.ReadLeShort();
+			int extraLen = inputBuffer.ReadLeShort();
+
+			bool isCrypted = (flags & 1) == 1;
+
+			byte[] buffer = new byte[nameLen];
+			inputBuffer.ReadRawBuffer(buffer);
+
+			string name = ZipStrings.ConvertToStringExt(flags, buffer);
+
+			entry = new ZipEntry(name, versionRequiredToExtract)
+			{
+				Flags = flags,
+				CompressionMethod = (CompressionMethod)method
+			};
+
+			if ((flags & 8) == 0)
+			{
+				entry.Crc = crc2 & 0xFFFFFFFFL;
+				entry.Size = size & 0xFFFFFFFFL;
+				entry.CompressedSize = csize & 0xFFFFFFFFL;
+
+				entry.CryptoCheckValue = (byte)((crc2 >> 24) & 0xff);
+			}
+			else
+			{
+				// This allows for GNU, WinZip and possibly other archives, the PKZIP spec
+				// says these values are zero under these circumstances.
+				if (crc2 != 0)
+				{
+					entry.Crc = crc2 & 0xFFFFFFFFL;
+				}
+
+				if (size != 0)
+				{
+					entry.Size = size & 0xFFFFFFFFL;
+				}
+
+				if (csize != 0)
+				{
+					entry.CompressedSize = csize & 0xFFFFFFFFL;
+				}
+
+				entry.CryptoCheckValue = (byte)((dostime >> 8) & 0xff);
+			}
+
+			entry.DosTime = dostime;
+
+			// If local header requires Zip64 is true then the extended header should contain
+			// both values.
+
+			// Handle extra data if present.  This can set/alter some fields of the entry.
+			if (extraLen > 0)
+			{
+				byte[] extra = new byte[extraLen];
+				inputBuffer.ReadRawBuffer(extra);
+				entry.ExtraData = extra;
+			}
+
+			entry.ProcessExtraData(true);
+			if (entry.CompressedSize >= 0)
+			{
+				csize = entry.CompressedSize;
+			}
+
+			if (entry.Size >= 0)
+			{
+				size = entry.Size;
+			}
+
+			if (method == (int)CompressionMethod.Stored && (!isCrypted && csize != size || (isCrypted && csize - ZipConstants.CryptoHeaderSize != size)))
+			{
+				throw new ZipException("Stored, but compressed != uncompressed");
+			}
+
+			// Determine how to handle reading of data if this is attempted.
+			if (entry.IsCompressionMethodSupported())
+			{
+				internalReader = new ReadDataHandler(InitialRead);
+			}
+			else
+			{
+				internalReader = new ReadDataHandler(ReadingNotSupported);
+			}
+
+			return entry;
+		}
+
+		/// <summary>
+		/// Read data descriptor at the end of compressed data.
+		/// </summary>
+		private void ReadDataDescriptor()
+		{
+			if (inputBuffer.ReadLeInt() != ZipConstants.DataDescriptorSignature)
+			{
+				throw new ZipException("Data descriptor signature not found");
+			}
+
+			entry.Crc = inputBuffer.ReadLeInt() & 0xFFFFFFFFL;
+
+			if (entry.LocalHeaderRequiresZip64)
+			{
+				csize = inputBuffer.ReadLeLong();
+				size = inputBuffer.ReadLeLong();
+			}
+			else
+			{
+				csize = inputBuffer.ReadLeInt();
+				size = inputBuffer.ReadLeInt();
+			}
+			entry.CompressedSize = csize;
+			entry.Size = size;
+		}
+
+		/// <summary>
+		/// Complete cleanup as the final part of closing.
+		/// </summary>
+		/// <param name="testCrc">True if the crc value should be tested</param>
+		private void CompleteCloseEntry(bool testCrc)
+		{
+			StopDecrypting();
+
+			if ((flags & 8) != 0)
+			{
+				ReadDataDescriptor();
+			}
+
+			size = 0;
+
+			if (testCrc &&
+				((crc.Value & 0xFFFFFFFFL) != entry.Crc) && (entry.Crc != -1))
+			{
+				throw new ZipException("CRC mismatch");
+			}
+
+			crc.Reset();
+
+			if (method == (int)CompressionMethod.Deflated)
+			{
+				inf.Reset();
+			}
+			entry = null;
+		}
+
+		/// <summary>
+		/// Closes the current zip entry and moves to the next one.
+		/// </summary>
+		/// <exception cref="InvalidOperationException">
+		/// The stream is closed
+		/// </exception>
+		/// <exception cref="ZipException">
+		/// The Zip stream ends early
+		/// </exception>
+		public void CloseEntry()
+		{
+			if (crc == null)
+			{
+				throw new InvalidOperationException("Closed");
+			}
+
+			if (entry == null)
+			{
+				return;
+			}
+
+			if (method == (int)CompressionMethod.Deflated)
+			{
+				if ((flags & 8) != 0)
+				{
+					// We don't know how much we must skip, read until end.
+					byte[] tmp = new byte[4096];
+
+					// Read will close this entry
+					while (Read(tmp, 0, tmp.Length) > 0)
+					{
+					}
+					return;
+				}
+
+				csize -= inf.TotalIn;
+				inputBuffer.Available += inf.RemainingInput;
+			}
+
+			if ((inputBuffer.Available > csize) && (csize >= 0))
+			{
+				inputBuffer.Available = (int)((long)inputBuffer.Available - csize);
+			}
+			else
+			{
+				csize -= inputBuffer.Available;
+				inputBuffer.Available = 0;
+				while (csize != 0)
+				{
+					long skipped = Skip(csize);
+
+					if (skipped <= 0)
+					{
+						throw new ZipException("Zip archive ends early.");
+					}
+
+					csize -= skipped;
+				}
+			}
+
+			CompleteCloseEntry(false);
+		}
+
+		/// <summary>
+		/// Returns 1 if there is an entry available
+		/// Otherwise returns 0.
+		/// </summary>
+		public override int Available
+		{
+			get
+			{
+				return entry != null ? 1 : 0;
+			}
+		}
+
+		/// <summary>
+		/// Returns the current size that can be read from the current entry if available
+		/// </summary>
+		/// <exception cref="ZipException">Thrown if the entry size is not known.</exception>
+		/// <exception cref="InvalidOperationException">Thrown if no entry is currently available.</exception>
+		public override long Length
+		{
+			get
+			{
+				if (entry != null)
+				{
+					if (entry.Size >= 0)
+					{
+						return entry.Size;
+					}
+					else
+					{
+						throw new ZipException("Length not available for the current entry");
+					}
+				}
+				else
+				{
+					throw new InvalidOperationException("No current entry");
+				}
+			}
+		}
+
+		/// <summary>
+		/// Reads a byte from the current zip entry.
+		/// </summary>
+		/// <returns>
+		/// The byte or -1 if end of stream is reached.
+		/// </returns>
+		public override int ReadByte()
+		{
+			byte[] b = new byte[1];
+			if (Read(b, 0, 1) <= 0)
+			{
+				return -1;
+			}
+			return b[0] & 0xff;
+		}
+
+		/// <summary>
+		/// Handle attempts to read by throwing an <see cref="InvalidOperationException"/>.
+		/// </summary>
+		/// <param name="destination">The destination array to store data in.</param>
+		/// <param name="offset">The offset at which data read should be stored.</param>
+		/// <param name="count">The maximum number of bytes to read.</param>
+		/// <returns>Returns the number of bytes actually read.</returns>
+		private int ReadingNotAvailable(byte[] destination, int offset, int count)
+		{
+			throw new InvalidOperationException("Unable to read from this stream");
+		}
+
+		/// <summary>
+		/// Handle attempts to read from this entry by throwing an exception
+		/// </summary>
+		private int ReadingNotSupported(byte[] destination, int offset, int count)
+		{
+			throw new ZipException("The compression method for this entry is not supported");
+		}
+
+		/// <summary>
+		/// Perform the initial read on an entry which may include
+		/// reading encryption headers and setting up inflation.
+		/// </summary>
+		/// <param name="destination">The destination to fill with data read.</param>
+		/// <param name="offset">The offset to start reading at.</param>
+		/// <param name="count">The maximum number of bytes to read.</param>
+		/// <returns>The actual number of bytes read.</returns>
+		private int InitialRead(byte[] destination, int offset, int count)
+		{
+			if (!CanDecompressEntry)
+			{
+				throw new ZipException("Library cannot extract this entry. Version required is (" + entry.Version + ")");
+			}
+
+			// Handle encryption if required.
+			if (entry.IsCrypted)
+			{
+				if (password == null)
+				{
+					throw new ZipException("No password set.");
+				}
+
+				// Generate and set crypto transform...
+				var managed = new PkzipClassicManaged();
+				byte[] key = PkzipClassic.GenerateKeys(ZipStrings.ConvertToArray(password));
+
+				inputBuffer.CryptoTransform = managed.CreateDecryptor(key, null);
+
+				byte[] cryptbuffer = new byte[ZipConstants.CryptoHeaderSize];
+				inputBuffer.ReadClearTextBuffer(cryptbuffer, 0, ZipConstants.CryptoHeaderSize);
+
+				if (cryptbuffer[ZipConstants.CryptoHeaderSize - 1] != entry.CryptoCheckValue)
+				{
+					throw new ZipException("Invalid password");
+				}
+
+				if (csize >= ZipConstants.CryptoHeaderSize)
+				{
+					csize -= ZipConstants.CryptoHeaderSize;
+				}
+				else if ((entry.Flags & (int)GeneralBitFlags.Descriptor) == 0)
+				{
+					throw new ZipException(string.Format("Entry compressed size {0} too small for encryption", csize));
+				}
+			}
+			else
+			{
+				inputBuffer.CryptoTransform = null;
+			}
+
+			if ((csize > 0) || ((flags & (int)GeneralBitFlags.Descriptor) != 0))
+			{
+				if ((method == (int)CompressionMethod.Deflated) && (inputBuffer.Available > 0))
+				{
+					inputBuffer.SetInflaterInput(inf);
+				}
+
+				internalReader = new ReadDataHandler(BodyRead);
+				return BodyRead(destination, offset, count);
+			}
+			else
+			{
+				internalReader = new ReadDataHandler(ReadingNotAvailable);
+				return 0;
+			}
+		}
+
+		/// <summary>
+		/// Read a block of bytes from the stream.
+		/// </summary>
+		/// <param name="buffer">The destination for the bytes.</param>
+		/// <param name="offset">The index to start storing data.</param>
+		/// <param name="count">The number of bytes to attempt to read.</param>
+		/// <returns>Returns the number of bytes read.</returns>
+		/// <remarks>Zero bytes read means end of stream.</remarks>
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			if (offset < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset), "Cannot be negative");
+			}
+
+			if (count < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(count), "Cannot be negative");
+			}
+
+			if ((buffer.Length - offset) < count)
+			{
+				throw new ArgumentException("Invalid offset/count combination");
+			}
+
+			return internalReader(buffer, offset, count);
+		}
+
+		/// <summary>
+		/// Reads a block of bytes from the current zip entry.
+		/// </summary>
+		/// <returns>
+		/// The number of bytes read (this may be less than the length requested, even before the end of stream), or 0 on end of stream.
+		/// </returns>
+		/// <exception name="IOException">
+		/// An i/o error occured.
+		/// </exception>
+		/// <exception cref="ZipException">
+		/// The deflated stream is corrupted.
+		/// </exception>
+		/// <exception cref="InvalidOperationException">
+		/// The stream is not open.
+		/// </exception>
+		private int BodyRead(byte[] buffer, int offset, int count)
+		{
+			if (crc == null)
+			{
+				throw new InvalidOperationException("Closed");
+			}
+
+			if ((entry == null) || (count <= 0))
+			{
+				return 0;
+			}
+
+			if (offset + count > buffer.Length)
+			{
+				throw new ArgumentException("Offset + count exceeds buffer size");
+			}
+
+			bool finished = false;
+
+			switch (method)
+			{
+				case (int)CompressionMethod.Deflated:
+					count = base.Read(buffer, offset, count);
+					if (count <= 0)
+					{
+						if (!inf.IsFinished)
+						{
+							throw new ZipException("Inflater not finished!");
+						}
+						inputBuffer.Available = inf.RemainingInput;
+
+						// A csize of -1 is from an unpatched local header
+						if ((flags & 8) == 0 &&
+							(inf.TotalIn != csize && csize != 0xFFFFFFFF && csize != -1 || inf.TotalOut != size))
+						{
+							throw new ZipException("Size mismatch: " + csize + ";" + size + " <-> " + inf.TotalIn + ";" + inf.TotalOut);
+						}
+						inf.Reset();
+						finished = true;
+					}
+					break;
+
+				case (int)CompressionMethod.Stored:
+					if ((count > csize) && (csize >= 0))
+					{
+						count = (int)csize;
+					}
+
+					if (count > 0)
+					{
+						count = inputBuffer.ReadClearTextBuffer(buffer, offset, count);
+						if (count > 0)
+						{
+							csize -= count;
+							size -= count;
+						}
+					}
+
+					if (csize == 0)
+					{
+						finished = true;
+					}
+					else
+					{
+						if (count < 0)
+						{
+							throw new ZipException("EOF in stored block");
+						}
+					}
+					break;
+			}
+
+			if (count > 0)
+			{
+				crc.Update(new ArraySegment<byte>(buffer, offset, count));
+			}
+
+			if (finished)
+			{
+				CompleteCloseEntry(true);
+			}
+
+			return count;
+		}
+
+		/// <summary>
+		/// Closes the zip input stream
+		/// </summary>
+		protected override void Dispose(bool disposing)
+		{
+			internalReader = new ReadDataHandler(ReadingNotAvailable);
+			crc = null;
+			entry = null;
+
+			base.Dispose(disposing);
+		}
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipNameTransform.cs

@@ -0,0 +1,250 @@
+using ICSharpCode.SharpZipLib.Core;
+using System;
+using System.IO;
+using System.Text;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// ZipNameTransform transforms names as per the Zip file naming convention.
+	/// </summary>
+	/// <remarks>The use of absolute names is supported although its use is not valid
+	/// according to Zip naming conventions, and should not be used if maximum compatability is desired.</remarks>
+	public class ZipNameTransform : INameTransform
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Initialize a new instance of <see cref="ZipNameTransform"></see>
+		/// </summary>
+		public ZipNameTransform()
+		{
+		}
+
+		/// <summary>
+		/// Initialize a new instance of <see cref="ZipNameTransform"></see>
+		/// </summary>
+		/// <param name="trimPrefix">The string to trim from the front of paths if found.</param>
+		public ZipNameTransform(string trimPrefix)
+		{
+			TrimPrefix = trimPrefix;
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Static constructor.
+		/// </summary>
+		static ZipNameTransform()
+		{
+			char[] invalidPathChars;
+			invalidPathChars = Path.GetInvalidPathChars();
+			int howMany = invalidPathChars.Length + 2;
+
+			InvalidEntryCharsRelaxed = new char[howMany];
+			Array.Copy(invalidPathChars, 0, InvalidEntryCharsRelaxed, 0, invalidPathChars.Length);
+			InvalidEntryCharsRelaxed[howMany - 1] = '*';
+			InvalidEntryCharsRelaxed[howMany - 2] = '?';
+
+			howMany = invalidPathChars.Length + 4;
+			InvalidEntryChars = new char[howMany];
+			Array.Copy(invalidPathChars, 0, InvalidEntryChars, 0, invalidPathChars.Length);
+			InvalidEntryChars[howMany - 1] = ':';
+			InvalidEntryChars[howMany - 2] = '\\';
+			InvalidEntryChars[howMany - 3] = '*';
+			InvalidEntryChars[howMany - 4] = '?';
+		}
+
+		/// <summary>
+		/// Transform a windows directory name according to the Zip file naming conventions.
+		/// </summary>
+		/// <param name="name">The directory name to transform.</param>
+		/// <returns>The transformed name.</returns>
+		public string TransformDirectory(string name)
+		{
+			name = TransformFile(name);
+			if (name.Length > 0)
+			{
+				if (!name.EndsWith("/", StringComparison.Ordinal))
+				{
+					name += "/";
+				}
+			}
+			else
+			{
+				throw new ZipException("Cannot have an empty directory name");
+			}
+			return name;
+		}
+
+		/// <summary>
+		/// Transform a windows file name according to the Zip file naming conventions.
+		/// </summary>
+		/// <param name="name">The file name to transform.</param>
+		/// <returns>The transformed name.</returns>
+		public string TransformFile(string name)
+		{
+			if (name != null)
+			{
+				string lowerName = name.ToLower();
+				if ((trimPrefix_ != null) && (lowerName.IndexOf(trimPrefix_, StringComparison.Ordinal) == 0))
+				{
+					name = name.Substring(trimPrefix_.Length);
+				}
+
+				name = name.Replace(@"\", "/");
+				name = WindowsPathUtils.DropPathRoot(name);
+
+				// Drop any leading slashes.
+				while ((name.Length > 0) && (name[0] == '/'))
+				{
+					name = name.Remove(0, 1);
+				}
+
+				// Drop any trailing slashes.
+				while ((name.Length > 0) && (name[name.Length - 1] == '/'))
+				{
+					name = name.Remove(name.Length - 1, 1);
+				}
+
+				// Convert consecutive // characters to /
+				int index = name.IndexOf("//", StringComparison.Ordinal);
+				while (index >= 0)
+				{
+					name = name.Remove(index, 1);
+					index = name.IndexOf("//", StringComparison.Ordinal);
+				}
+
+				name = MakeValidName(name, '_');
+			}
+			else
+			{
+				name = string.Empty;
+			}
+			return name;
+		}
+
+		/// <summary>
+		/// Get/set the path prefix to be trimmed from paths if present.
+		/// </summary>
+		/// <remarks>The prefix is trimmed before any conversion from
+		/// a windows path is done.</remarks>
+		public string TrimPrefix
+		{
+			get { return trimPrefix_; }
+			set
+			{
+				trimPrefix_ = value;
+				if (trimPrefix_ != null)
+				{
+					trimPrefix_ = trimPrefix_.ToLower();
+				}
+			}
+		}
+
+		/// <summary>
+		/// Force a name to be valid by replacing invalid characters with a fixed value
+		/// </summary>
+		/// <param name="name">The name to force valid</param>
+		/// <param name="replacement">The replacement character to use.</param>
+		/// <returns>Returns a valid name</returns>
+		private static string MakeValidName(string name, char replacement)
+		{
+			int index = name.IndexOfAny(InvalidEntryChars);
+			if (index >= 0)
+			{
+				var builder = new StringBuilder(name);
+
+				while (index >= 0)
+				{
+					builder[index] = replacement;
+
+					if (index >= name.Length)
+					{
+						index = -1;
+					}
+					else
+					{
+						index = name.IndexOfAny(InvalidEntryChars, index + 1);
+					}
+				}
+				name = builder.ToString();
+			}
+
+			if (name.Length > 0xffff)
+			{
+				throw new PathTooLongException();
+			}
+
+			return name;
+		}
+
+		/// <summary>
+		/// Test a name to see if it is a valid name for a zip entry.
+		/// </summary>
+		/// <param name="name">The name to test.</param>
+		/// <param name="relaxed">If true checking is relaxed about windows file names and absolute paths.</param>
+		/// <returns>Returns true if the name is a valid zip name; false otherwise.</returns>
+		/// <remarks>Zip path names are actually in Unix format, and should only contain relative paths.
+		/// This means that any path stored should not contain a drive or
+		/// device letter, or a leading slash.  All slashes should forward slashes '/'.
+		/// An empty name is valid for a file where the input comes from standard input.
+		/// A null name is not considered valid.
+		/// </remarks>
+		public static bool IsValidName(string name, bool relaxed)
+		{
+			bool result = (name != null);
+
+			if (result)
+			{
+				if (relaxed)
+				{
+					result = name.IndexOfAny(InvalidEntryCharsRelaxed) < 0;
+				}
+				else
+				{
+					result =
+						(name.IndexOfAny(InvalidEntryChars) < 0) &&
+						(name.IndexOf('/') != 0);
+				}
+			}
+
+			return result;
+		}
+
+		/// <summary>
+		/// Test a name to see if it is a valid name for a zip entry.
+		/// </summary>
+		/// <param name="name">The name to test.</param>
+		/// <returns>Returns true if the name is a valid zip name; false otherwise.</returns>
+		/// <remarks>Zip path names are actually in unix format,
+		/// and should only contain relative paths if a path is present.
+		/// This means that the path stored should not contain a drive or
+		/// device letter, or a leading slash.  All slashes should forward slashes '/'.
+		/// An empty name is valid where the input comes from standard input.
+		/// A null name is not considered valid.
+		/// </remarks>
+		public static bool IsValidName(string name)
+		{
+			bool result =
+				(name != null) &&
+				(name.IndexOfAny(InvalidEntryChars) < 0) &&
+				(name.IndexOf('/') != 0)
+				;
+			return result;
+		}
+
+		#region Instance Fields
+
+		private string trimPrefix_;
+
+		#endregion Instance Fields
+
+		#region Class Fields
+
+		private static readonly char[] InvalidEntryChars;
+		private static readonly char[] InvalidEntryCharsRelaxed;
+
+		#endregion Class Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipOutputStream.cs

@@ -0,0 +1,949 @@
+using ICSharpCode.SharpZipLib.Checksum;
+using ICSharpCode.SharpZipLib.Zip.Compression;
+using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// This is a DeflaterOutputStream that writes the files into a zip
+	/// archive one after another.  It has a special method to start a new
+	/// zip entry.  The zip entries contains information about the file name
+	/// size, compressed size, CRC, etc.
+	///
+	/// It includes support for Stored and Deflated entries.
+	/// This class is not thread safe.
+	/// <br/>
+	/// <br/>Author of the original java version : Jochen Hoenicke
+	/// </summary>
+	/// <example> This sample shows how to create a zip file
+	/// <code>
+	/// using System;
+	/// using System.IO;
+	///
+	/// using ICSharpCode.SharpZipLib.Core;
+	/// using ICSharpCode.SharpZipLib.Zip;
+	///
+	/// class MainClass
+	/// {
+	/// 	public static void Main(string[] args)
+	/// 	{
+	/// 		string[] filenames = Directory.GetFiles(args[0]);
+	/// 		byte[] buffer = new byte[4096];
+	///
+	/// 		using ( ZipOutputStream s = new ZipOutputStream(File.Create(args[1])) ) {
+	///
+	/// 			s.SetLevel(9); // 0 - store only to 9 - means best compression
+	///
+	/// 			foreach (string file in filenames) {
+	/// 				ZipEntry entry = new ZipEntry(file);
+	/// 				s.PutNextEntry(entry);
+	///
+	/// 				using (FileStream fs = File.OpenRead(file)) {
+	///						StreamUtils.Copy(fs, s, buffer);
+	/// 				}
+	/// 			}
+	/// 		}
+	/// 	}
+	/// }
+	/// </code>
+	/// </example>
+	public class ZipOutputStream : DeflaterOutputStream
+	{
+		#region Constructors
+
+		/// <summary>
+		/// Creates a new Zip output stream, writing a zip archive.
+		/// </summary>
+		/// <param name="baseOutputStream">
+		/// The output stream to which the archive contents are written.
+		/// </param>
+		public ZipOutputStream(Stream baseOutputStream)
+			: base(baseOutputStream, new Deflater(Deflater.DEFAULT_COMPRESSION, true))
+		{
+		}
+
+		/// <summary>
+		/// Creates a new Zip output stream, writing a zip archive.
+		/// </summary>
+		/// <param name="baseOutputStream">The output stream to which the archive contents are written.</param>
+		/// <param name="bufferSize">Size of the buffer to use.</param>
+		public ZipOutputStream(Stream baseOutputStream, int bufferSize)
+			: base(baseOutputStream, new Deflater(Deflater.DEFAULT_COMPRESSION, true), bufferSize)
+		{
+		}
+
+		#endregion Constructors
+
+		/// <summary>
+		/// Gets a flag value of true if the central header has been added for this archive; false if it has not been added.
+		/// </summary>
+		/// <remarks>No further entries can be added once this has been done.</remarks>
+		public bool IsFinished
+		{
+			get
+			{
+				return entries == null;
+			}
+		}
+
+		/// <summary>
+		/// Set the zip file comment.
+		/// </summary>
+		/// <param name="comment">
+		/// The comment text for the entire archive.
+		/// </param>
+		/// <exception name ="ArgumentOutOfRangeException">
+		/// The converted comment is longer than 0xffff bytes.
+		/// </exception>
+		public void SetComment(string comment)
+		{
+			// TODO: Its not yet clear how to handle unicode comments here.
+			byte[] commentBytes = ZipStrings.ConvertToArray(comment);
+			if (commentBytes.Length > 0xffff)
+			{
+				throw new ArgumentOutOfRangeException(nameof(comment));
+			}
+			zipComment = commentBytes;
+		}
+
+		/// <summary>
+		/// Sets the compression level.  The new level will be activated
+		/// immediately.
+		/// </summary>
+		/// <param name="level">The new compression level (1 to 9).</param>
+		/// <exception cref="ArgumentOutOfRangeException">
+		/// Level specified is not supported.
+		/// </exception>
+		/// <see cref="ICSharpCode.SharpZipLib.Zip.Compression.Deflater"/>
+		public void SetLevel(int level)
+		{
+			deflater_.SetLevel(level);
+			defaultCompressionLevel = level;
+		}
+
+		/// <summary>
+		/// Get the current deflater compression level
+		/// </summary>
+		/// <returns>The current compression level</returns>
+		public int GetLevel()
+		{
+			return deflater_.GetLevel();
+		}
+
+		/// <summary>
+		/// Get / set a value indicating how Zip64 Extension usage is determined when adding entries.
+		/// </summary>
+		/// <remarks>Older archivers may not understand Zip64 extensions.
+		/// If backwards compatability is an issue be careful when adding <see cref="ZipEntry.Size">entries</see> to an archive.
+		/// Setting this property to off is workable but less desirable as in those circumstances adding a file
+		/// larger then 4GB will fail.</remarks>
+		public UseZip64 UseZip64
+		{
+			get { return useZip64_; }
+			set { useZip64_ = value; }
+		}
+
+		/// <summary>
+		/// Write an unsigned short in little endian byte order.
+		/// </summary>
+		private void WriteLeShort(int value)
+		{
+			unchecked
+			{
+				baseOutputStream_.WriteByte((byte)(value & 0xff));
+				baseOutputStream_.WriteByte((byte)((value >> 8) & 0xff));
+			}
+		}
+
+		/// <summary>
+		/// Write an int in little endian byte order.
+		/// </summary>
+		private void WriteLeInt(int value)
+		{
+			unchecked
+			{
+				WriteLeShort(value);
+				WriteLeShort(value >> 16);
+			}
+		}
+
+		/// <summary>
+		/// Write an int in little endian byte order.
+		/// </summary>
+		private void WriteLeLong(long value)
+		{
+			unchecked
+			{
+				WriteLeInt((int)value);
+				WriteLeInt((int)(value >> 32));
+			}
+		}
+
+		/// <summary>
+		/// Starts a new Zip entry. It automatically closes the previous
+		/// entry if present.
+		/// All entry elements bar name are optional, but must be correct if present.
+		/// If the compression method is stored and the output is not patchable
+		/// the compression for that entry is automatically changed to deflate level 0
+		/// </summary>
+		/// <param name="entry">
+		/// the entry.
+		/// </param>
+		/// <exception cref="System.ArgumentNullException">
+		/// if entry passed is null.
+		/// </exception>
+		/// <exception cref="System.IO.IOException">
+		/// if an I/O error occured.
+		/// </exception>
+		/// <exception cref="System.InvalidOperationException">
+		/// if stream was finished
+		/// </exception>
+		/// <exception cref="ZipException">
+		/// Too many entries in the Zip file<br/>
+		/// Entry name is too long<br/>
+		/// Finish has already been called<br/>
+		/// </exception>
+		public void PutNextEntry(ZipEntry entry)
+		{
+			if (entry == null)
+			{
+				throw new ArgumentNullException(nameof(entry));
+			}
+
+			if (entries == null)
+			{
+				throw new InvalidOperationException("ZipOutputStream was finished");
+			}
+
+			if (curEntry != null)
+			{
+				CloseEntry();
+			}
+
+			if (entries.Count == int.MaxValue)
+			{
+				throw new ZipException("Too many entries for Zip file");
+			}
+
+			CompressionMethod method = entry.CompressionMethod;
+			int compressionLevel = defaultCompressionLevel;
+
+			// Clear flags that the library manages internally
+			entry.Flags &= (int)GeneralBitFlags.UnicodeText;
+			patchEntryHeader = false;
+
+			bool headerInfoAvailable;
+
+			// No need to compress - definitely no data.
+			if (entry.Size == 0)
+			{
+				entry.CompressedSize = entry.Size;
+				entry.Crc = 0;
+				method = CompressionMethod.Stored;
+				headerInfoAvailable = true;
+			}
+			else
+			{
+				headerInfoAvailable = (entry.Size >= 0) && entry.HasCrc && entry.CompressedSize >= 0;
+
+				// Switch to deflation if storing isnt possible.
+				if (method == CompressionMethod.Stored)
+				{
+					if (!headerInfoAvailable)
+					{
+						if (!CanPatchEntries)
+						{
+							// Can't patch entries so storing is not possible.
+							method = CompressionMethod.Deflated;
+							compressionLevel = 0;
+						}
+					}
+					else // entry.size must be > 0
+					{
+						entry.CompressedSize = entry.Size;
+						headerInfoAvailable = entry.HasCrc;
+					}
+				}
+			}
+
+			if (headerInfoAvailable == false)
+			{
+				if (CanPatchEntries == false)
+				{
+					// Only way to record size and compressed size is to append a data descriptor
+					// after compressed data.
+
+					// Stored entries of this form have already been converted to deflating.
+					entry.Flags |= 8;
+				}
+				else
+				{
+					patchEntryHeader = true;
+				}
+			}
+
+			if (Password != null)
+			{
+				entry.IsCrypted = true;
+				if (entry.Crc < 0)
+				{
+					// Need to append a data descriptor as the crc isnt available for use
+					// with encryption, the date is used instead.  Setting the flag
+					// indicates this to the decompressor.
+					entry.Flags |= 8;
+				}
+			}
+
+			entry.Offset = offset;
+			entry.CompressionMethod = (CompressionMethod)method;
+
+			curMethod = method;
+			sizePatchPos = -1;
+
+			if ((useZip64_ == UseZip64.On) || ((entry.Size < 0) && (useZip64_ == UseZip64.Dynamic)))
+			{
+				entry.ForceZip64();
+			}
+
+			// Write the local file header
+			WriteLeInt(ZipConstants.LocalHeaderSignature);
+
+			WriteLeShort(entry.Version);
+			WriteLeShort(entry.Flags);
+			WriteLeShort((byte)entry.CompressionMethodForHeader);
+			WriteLeInt((int)entry.DosTime);
+
+			// TODO: Refactor header writing.  Its done in several places.
+			if (headerInfoAvailable)
+			{
+				WriteLeInt((int)entry.Crc);
+				if (entry.LocalHeaderRequiresZip64)
+				{
+					WriteLeInt(-1);
+					WriteLeInt(-1);
+				}
+				else
+				{
+					WriteLeInt(entry.IsCrypted ? (int)entry.CompressedSize + ZipConstants.CryptoHeaderSize : (int)entry.CompressedSize);
+					WriteLeInt((int)entry.Size);
+				}
+			}
+			else
+			{
+				if (patchEntryHeader)
+				{
+					crcPatchPos = baseOutputStream_.Position;
+				}
+				WriteLeInt(0);  // Crc
+
+				if (patchEntryHeader)
+				{
+					sizePatchPos = baseOutputStream_.Position;
+				}
+
+				// For local header both sizes appear in Zip64 Extended Information
+				if (entry.LocalHeaderRequiresZip64 || patchEntryHeader)
+				{
+					WriteLeInt(-1);
+					WriteLeInt(-1);
+				}
+				else
+				{
+					WriteLeInt(0);  // Compressed size
+					WriteLeInt(0);  // Uncompressed size
+				}
+			}
+
+			byte[] name = ZipStrings.ConvertToArray(entry.Flags, entry.Name);
+
+			if (name.Length > 0xFFFF)
+			{
+				throw new ZipException("Entry name too long.");
+			}
+
+			var ed = new ZipExtraData(entry.ExtraData);
+
+			if (entry.LocalHeaderRequiresZip64)
+			{
+				ed.StartNewEntry();
+				if (headerInfoAvailable)
+				{
+					ed.AddLeLong(entry.Size);
+					ed.AddLeLong(entry.CompressedSize);
+				}
+				else
+				{
+					ed.AddLeLong(-1);
+					ed.AddLeLong(-1);
+				}
+				ed.AddNewEntry(1);
+
+				if (!ed.Find(1))
+				{
+					throw new ZipException("Internal error cant find extra data");
+				}
+
+				if (patchEntryHeader)
+				{
+					sizePatchPos = ed.CurrentReadIndex;
+				}
+			}
+			else
+			{
+				ed.Delete(1);
+			}
+
+			if (entry.AESKeySize > 0)
+			{
+				AddExtraDataAES(entry, ed);
+			}
+			byte[] extra = ed.GetEntryData();
+
+			WriteLeShort(name.Length);
+			WriteLeShort(extra.Length);
+
+			if (name.Length > 0)
+			{
+				baseOutputStream_.Write(name, 0, name.Length);
+			}
+
+			if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
+			{
+				sizePatchPos += baseOutputStream_.Position;
+			}
+
+			if (extra.Length > 0)
+			{
+				baseOutputStream_.Write(extra, 0, extra.Length);
+			}
+
+			offset += ZipConstants.LocalHeaderBaseSize + name.Length + extra.Length;
+			// Fix offsetOfCentraldir for AES
+			if (entry.AESKeySize > 0)
+				offset += entry.AESOverheadSize;
+
+			// Activate the entry.
+			curEntry = entry;
+			crc.Reset();
+			if (method == CompressionMethod.Deflated)
+			{
+				deflater_.Reset();
+				deflater_.SetLevel(compressionLevel);
+			}
+			size = 0;
+
+			if (entry.IsCrypted)
+			{
+				if (entry.AESKeySize > 0)
+				{
+					WriteAESHeader(entry);
+				}
+				else
+				{
+					if (entry.Crc < 0)
+					{            // so testing Zip will says its ok
+						WriteEncryptionHeader(entry.DosTime << 16);
+					}
+					else
+					{
+						WriteEncryptionHeader(entry.Crc);
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// Closes the current entry, updating header and footer information as required
+		/// </summary>
+		/// <exception cref="System.IO.IOException">
+		/// An I/O error occurs.
+		/// </exception>
+		/// <exception cref="System.InvalidOperationException">
+		/// No entry is active.
+		/// </exception>
+		public void CloseEntry()
+		{
+			if (curEntry == null)
+			{
+				throw new InvalidOperationException("No open entry");
+			}
+
+			long csize = size;
+
+			// First finish the deflater, if appropriate
+			if (curMethod == CompressionMethod.Deflated)
+			{
+				if (size >= 0)
+				{
+					base.Finish();
+					csize = deflater_.TotalOut;
+				}
+				else
+				{
+					deflater_.Reset();
+				}
+			}
+			else if (curMethod == CompressionMethod.Stored)
+			{
+				// This is done by Finsh() for Deflated entries, but we need to do it
+				// ourselves for Stored ones
+				base.GetAuthCodeIfAES();
+			}
+
+			// Write the AES Authentication Code (a hash of the compressed and encrypted data)
+			if (curEntry.AESKeySize > 0)
+			{
+				baseOutputStream_.Write(AESAuthCode, 0, 10);
+			}
+
+			if (curEntry.Size < 0)
+			{
+				curEntry.Size = size;
+			}
+			else if (curEntry.Size != size)
+			{
+				throw new ZipException("size was " + size + ", but I expected " + curEntry.Size);
+			}
+
+			if (curEntry.CompressedSize < 0)
+			{
+				curEntry.CompressedSize = csize;
+			}
+			else if (curEntry.CompressedSize != csize)
+			{
+				throw new ZipException("compressed size was " + csize + ", but I expected " + curEntry.CompressedSize);
+			}
+
+			if (curEntry.Crc < 0)
+			{
+				curEntry.Crc = crc.Value;
+			}
+			else if (curEntry.Crc != crc.Value)
+			{
+				throw new ZipException("crc was " + crc.Value + ", but I expected " + curEntry.Crc);
+			}
+
+			offset += csize;
+
+			if (curEntry.IsCrypted)
+			{
+				if (curEntry.AESKeySize > 0)
+				{
+					curEntry.CompressedSize += curEntry.AESOverheadSize;
+				}
+				else
+				{
+					curEntry.CompressedSize += ZipConstants.CryptoHeaderSize;
+				}
+			}
+
+			// Patch the header if possible
+			if (patchEntryHeader)
+			{
+				patchEntryHeader = false;
+
+				long curPos = baseOutputStream_.Position;
+				baseOutputStream_.Seek(crcPatchPos, SeekOrigin.Begin);
+				WriteLeInt((int)curEntry.Crc);
+
+				if (curEntry.LocalHeaderRequiresZip64)
+				{
+					if (sizePatchPos == -1)
+					{
+						throw new ZipException("Entry requires zip64 but this has been turned off");
+					}
+
+					baseOutputStream_.Seek(sizePatchPos, SeekOrigin.Begin);
+					WriteLeLong(curEntry.Size);
+					WriteLeLong(curEntry.CompressedSize);
+				}
+				else
+				{
+					WriteLeInt((int)curEntry.CompressedSize);
+					WriteLeInt((int)curEntry.Size);
+				}
+				baseOutputStream_.Seek(curPos, SeekOrigin.Begin);
+			}
+
+			// Add data descriptor if flagged as required
+			if ((curEntry.Flags & 8) != 0)
+			{
+				WriteLeInt(ZipConstants.DataDescriptorSignature);
+				WriteLeInt(unchecked((int)curEntry.Crc));
+
+				if (curEntry.LocalHeaderRequiresZip64)
+				{
+					WriteLeLong(curEntry.CompressedSize);
+					WriteLeLong(curEntry.Size);
+					offset += ZipConstants.Zip64DataDescriptorSize;
+				}
+				else
+				{
+					WriteLeInt((int)curEntry.CompressedSize);
+					WriteLeInt((int)curEntry.Size);
+					offset += ZipConstants.DataDescriptorSize;
+				}
+			}
+
+			entries.Add(curEntry);
+			curEntry = null;
+		}
+
+		private void WriteEncryptionHeader(long crcValue)
+		{
+			offset += ZipConstants.CryptoHeaderSize;
+
+			InitializePassword(Password);
+
+			byte[] cryptBuffer = new byte[ZipConstants.CryptoHeaderSize];
+			var rnd = new Random();
+			rnd.NextBytes(cryptBuffer);
+			cryptBuffer[11] = (byte)(crcValue >> 24);
+
+			EncryptBlock(cryptBuffer, 0, cryptBuffer.Length);
+			baseOutputStream_.Write(cryptBuffer, 0, cryptBuffer.Length);
+		}
+
+		private static void AddExtraDataAES(ZipEntry entry, ZipExtraData extraData)
+		{
+			// Vendor Version: AE-1 IS 1. AE-2 is 2. With AE-2 no CRC is required and 0 is stored.
+			const int VENDOR_VERSION = 2;
+			// Vendor ID is the two ASCII characters "AE".
+			const int VENDOR_ID = 0x4541; //not 6965;
+			extraData.StartNewEntry();
+			// Pack AES extra data field see http://www.winzip.com/aes_info.htm
+			//extraData.AddLeShort(7);							// Data size (currently 7)
+			extraData.AddLeShort(VENDOR_VERSION);               // 2 = AE-2
+			extraData.AddLeShort(VENDOR_ID);                    // "AE"
+			extraData.AddData(entry.AESEncryptionStrength);     //  1 = 128, 2 = 192, 3 = 256
+			extraData.AddLeShort((int)entry.CompressionMethod); // The actual compression method used to compress the file
+			extraData.AddNewEntry(0x9901);
+		}
+
+		// Replaces WriteEncryptionHeader for AES
+		//
+		private void WriteAESHeader(ZipEntry entry)
+		{
+			byte[] salt;
+			byte[] pwdVerifier;
+			InitializeAESPassword(entry, Password, out salt, out pwdVerifier);
+			// File format for AES:
+			// Size (bytes)   Content
+			// ------------   -------
+			// Variable       Salt value
+			// 2              Password verification value
+			// Variable       Encrypted file data
+			// 10             Authentication code
+			//
+			// Value in the "compressed size" fields of the local file header and the central directory entry
+			// is the total size of all the items listed above. In other words, it is the total size of the
+			// salt value, password verification value, encrypted data, and authentication code.
+			baseOutputStream_.Write(salt, 0, salt.Length);
+			baseOutputStream_.Write(pwdVerifier, 0, pwdVerifier.Length);
+		}
+
+		/// <summary>
+		/// Writes the given buffer to the current entry.
+		/// </summary>
+		/// <param name="buffer">The buffer containing data to write.</param>
+		/// <param name="offset">The offset of the first byte to write.</param>
+		/// <param name="count">The number of bytes to write.</param>
+		/// <exception cref="ZipException">Archive size is invalid</exception>
+		/// <exception cref="System.InvalidOperationException">No entry is active.</exception>
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			if (curEntry == null)
+			{
+				throw new InvalidOperationException("No open entry.");
+			}
+
+			if (buffer == null)
+			{
+				throw new ArgumentNullException(nameof(buffer));
+			}
+
+			if (offset < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(offset), "Cannot be negative");
+			}
+
+			if (count < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(count), "Cannot be negative");
+			}
+
+			if ((buffer.Length - offset) < count)
+			{
+				throw new ArgumentException("Invalid offset/count combination");
+			}
+
+			crc.Update(new ArraySegment<byte>(buffer, offset, count));
+			size += count;
+
+			switch (curMethod)
+			{
+				case CompressionMethod.Deflated:
+					base.Write(buffer, offset, count);
+					break;
+
+				case CompressionMethod.Stored:
+					if (Password != null)
+					{
+						CopyAndEncrypt(buffer, offset, count);
+					}
+					else
+					{
+						baseOutputStream_.Write(buffer, offset, count);
+					}
+					break;
+			}
+		}
+
+		private void CopyAndEncrypt(byte[] buffer, int offset, int count)
+		{
+			const int CopyBufferSize = 4096;
+			byte[] localBuffer = new byte[CopyBufferSize];
+			while (count > 0)
+			{
+				int bufferCount = (count < CopyBufferSize) ? count : CopyBufferSize;
+
+				Array.Copy(buffer, offset, localBuffer, 0, bufferCount);
+				EncryptBlock(localBuffer, 0, bufferCount);
+				baseOutputStream_.Write(localBuffer, 0, bufferCount);
+				count -= bufferCount;
+				offset += bufferCount;
+			}
+		}
+
+		/// <summary>
+		/// Finishes the stream.  This will write the central directory at the
+		/// end of the zip file and flush the stream.
+		/// </summary>
+		/// <remarks>
+		/// This is automatically called when the stream is closed.
+		/// </remarks>
+		/// <exception cref="System.IO.IOException">
+		/// An I/O error occurs.
+		/// </exception>
+		/// <exception cref="ZipException">
+		/// Comment exceeds the maximum length<br/>
+		/// Entry name exceeds the maximum length
+		/// </exception>
+		public override void Finish()
+		{
+			if (entries == null)
+			{
+				return;
+			}
+
+			if (curEntry != null)
+			{
+				CloseEntry();
+			}
+
+			long numEntries = entries.Count;
+			long sizeEntries = 0;
+
+			foreach (ZipEntry entry in entries)
+			{
+				WriteLeInt(ZipConstants.CentralHeaderSignature);
+				WriteLeShort(ZipConstants.VersionMadeBy);
+				WriteLeShort(entry.Version);
+				WriteLeShort(entry.Flags);
+				WriteLeShort((short)entry.CompressionMethodForHeader);
+				WriteLeInt((int)entry.DosTime);
+				WriteLeInt((int)entry.Crc);
+
+				if (entry.IsZip64Forced() ||
+					(entry.CompressedSize >= uint.MaxValue))
+				{
+					WriteLeInt(-1);
+				}
+				else
+				{
+					WriteLeInt((int)entry.CompressedSize);
+				}
+
+				if (entry.IsZip64Forced() ||
+					(entry.Size >= uint.MaxValue))
+				{
+					WriteLeInt(-1);
+				}
+				else
+				{
+					WriteLeInt((int)entry.Size);
+				}
+
+				byte[] name = ZipStrings.ConvertToArray(entry.Flags, entry.Name);
+
+				if (name.Length > 0xffff)
+				{
+					throw new ZipException("Name too long.");
+				}
+
+				var ed = new ZipExtraData(entry.ExtraData);
+
+				if (entry.CentralHeaderRequiresZip64)
+				{
+					ed.StartNewEntry();
+					if (entry.IsZip64Forced() ||
+						(entry.Size >= 0xffffffff))
+					{
+						ed.AddLeLong(entry.Size);
+					}
+
+					if (entry.IsZip64Forced() ||
+						(entry.CompressedSize >= 0xffffffff))
+					{
+						ed.AddLeLong(entry.CompressedSize);
+					}
+
+					if (entry.Offset >= 0xffffffff)
+					{
+						ed.AddLeLong(entry.Offset);
+					}
+
+					ed.AddNewEntry(1);
+				}
+				else
+				{
+					ed.Delete(1);
+				}
+
+				if (entry.AESKeySize > 0)
+				{
+					AddExtraDataAES(entry, ed);
+				}
+				byte[] extra = ed.GetEntryData();
+
+				byte[] entryComment =
+					(entry.Comment != null) ?
+					ZipStrings.ConvertToArray(entry.Flags, entry.Comment) :
+					new byte[0];
+
+				if (entryComment.Length > 0xffff)
+				{
+					throw new ZipException("Comment too long.");
+				}
+
+				WriteLeShort(name.Length);
+				WriteLeShort(extra.Length);
+				WriteLeShort(entryComment.Length);
+				WriteLeShort(0);    // disk number
+				WriteLeShort(0);    // internal file attributes
+									// external file attributes
+
+				if (entry.ExternalFileAttributes != -1)
+				{
+					WriteLeInt(entry.ExternalFileAttributes);
+				}
+				else
+				{
+					if (entry.IsDirectory)
+					{                         // mark entry as directory (from nikolam.AT.perfectinfo.com)
+						WriteLeInt(16);
+					}
+					else
+					{
+						WriteLeInt(0);
+					}
+				}
+
+				if (entry.Offset >= uint.MaxValue)
+				{
+					WriteLeInt(-1);
+				}
+				else
+				{
+					WriteLeInt((int)entry.Offset);
+				}
+
+				if (name.Length > 0)
+				{
+					baseOutputStream_.Write(name, 0, name.Length);
+				}
+
+				if (extra.Length > 0)
+				{
+					baseOutputStream_.Write(extra, 0, extra.Length);
+				}
+
+				if (entryComment.Length > 0)
+				{
+					baseOutputStream_.Write(entryComment, 0, entryComment.Length);
+				}
+
+				sizeEntries += ZipConstants.CentralHeaderBaseSize + name.Length + extra.Length + entryComment.Length;
+			}
+
+			using (ZipHelperStream zhs = new ZipHelperStream(baseOutputStream_))
+			{
+				zhs.WriteEndOfCentralDirectory(numEntries, sizeEntries, offset, zipComment);
+			}
+
+			entries = null;
+		}
+
+		#region Instance Fields
+
+		/// <summary>
+		/// The entries for the archive.
+		/// </summary>
+		private List<ZipEntry> entries = new List<ZipEntry>();
+
+		/// <summary>
+		/// Used to track the crc of data added to entries.
+		/// </summary>
+		private Crc32 crc = new Crc32();
+
+		/// <summary>
+		/// The current entry being added.
+		/// </summary>
+		private ZipEntry curEntry;
+
+		private int defaultCompressionLevel = Deflater.DEFAULT_COMPRESSION;
+
+		private CompressionMethod curMethod = CompressionMethod.Deflated;
+
+		/// <summary>
+		/// Used to track the size of data for an entry during writing.
+		/// </summary>
+		private long size;
+
+		/// <summary>
+		/// Offset to be recorded for each entry in the central header.
+		/// </summary>
+		private long offset;
+
+		/// <summary>
+		/// Comment for the entire archive recorded in central header.
+		/// </summary>
+		private byte[] zipComment = new byte[0];
+
+		/// <summary>
+		/// Flag indicating that header patching is required for the current entry.
+		/// </summary>
+		private bool patchEntryHeader;
+
+		/// <summary>
+		/// Position to patch crc
+		/// </summary>
+		private long crcPatchPos = -1;
+
+		/// <summary>
+		/// Position to patch size.
+		/// </summary>
+		private long sizePatchPos = -1;
+
+		// Default is dynamic which is not backwards compatible and can cause problems
+		// with XP's built in compression which cant read Zip64 archives.
+		// However it does avoid the situation were a large file is added and cannot be completed correctly.
+		// NOTE: Setting the size for entries before they are added is the best solution!
+		private UseZip64 useZip64_ = UseZip64.Dynamic;
+
+		#endregion Instance Fields
+	}
+}

ICSharpCode.SharpZipLib/Zip/ZipStrings.cs

@@ -0,0 +1,193 @@
+using System;
+using System.Text;
+
+namespace ICSharpCode.SharpZipLib.Zip
+{
+	/// <summary>
+	/// This static class contains functions for encoding and decoding zip file strings
+	/// </summary>
+	public static class ZipStrings
+	{
+		static ZipStrings()
+		{
+			try
+			{
+				var platformCodepage = Encoding.GetEncoding(0).CodePage;
+				SystemDefaultCodePage = (platformCodepage == 1 || platformCodepage == 2 || platformCodepage == 3 || platformCodepage == 42) ? FallbackCodePage : platformCodepage;
+			}
+			catch
+			{
+				SystemDefaultCodePage = FallbackCodePage;
+			}
+		}
+
+		/// <summary>Code page backing field</summary>
+		/// <remarks>
+		/// The original Zip specification (https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT) states
+		/// that file names should only be encoded with IBM Code Page 437 or UTF-8.
+		/// In practice, most zip apps use OEM or system encoding (typically cp437 on Windows).
+		/// Let's be good citizens and default to UTF-8 http://utf8everywhere.org/
+		/// </remarks>
+		private static int codePage = AutomaticCodePage;
+
+		/// Automatically select codepage while opening archive
+		/// see https://github.com/icsharpcode/SharpZipLib/pull/280#issuecomment-433608324
+		/// 
+		private const int AutomaticCodePage = -1;
+
+		/// <summary>
+		/// Encoding used for string conversion. Setting this to 65001 (UTF-8) will
+		/// also set the Language encoding flag to indicate UTF-8 encoded file names.
+		/// </summary>
+		public static int CodePage
+		{
+			get
+			{
+				return codePage == AutomaticCodePage? Encoding.UTF8.CodePage:codePage;
+			}
+			set
+			{
+				if ((value < 0) || (value > 65535) ||
+					(value == 1) || (value == 2) || (value == 3) || (value == 42))
+				{
+					throw new ArgumentOutOfRangeException(nameof(value));
+				}
+
+				codePage = value;
+			}
+		}
+
+		private const int FallbackCodePage = 437;
+
+		/// <summary>
+		/// Attempt to get the operating system default codepage, or failing that, to
+		/// the fallback code page IBM 437.
+		/// </summary>
+		public static int SystemDefaultCodePage { get; }
+
+		/// <summary>
+		/// Get wether the default codepage is set to UTF-8. Setting this property to false will
+		/// set the <see cref="CodePage"/> to <see cref="SystemDefaultCodePage"/>
+		/// </summary>
+		/// <remarks>
+		/// /// Get OEM codepage from NetFX, which parses the NLP file with culture info table etc etc.
+		/// But sometimes it yields the special value of 1 which is nicknamed <c>CodePageNoOEM</c> in <see cref="Encoding"/> sources (might also mean <c>CP_OEMCP</c>, but Encoding puts it so).
+		/// This was observed on Ukranian and Hindu systems.
+		/// Given this value, <see cref="Encoding.GetEncoding(int)"/> throws an <see cref="ArgumentException"/>.
+		/// So replace it with <see cref="FallbackCodePage"/>, (IBM 437 which is the default code page in a default Windows installation console.
+		/// </remarks>
+		public static bool UseUnicode
+		{
+			get
+			{
+				return codePage == Encoding.UTF8.CodePage;
+			}
+			set
+			{
+				if (value)
+				{
+					codePage = Encoding.UTF8.CodePage;
+				}
+				else
+				{
+					codePage = SystemDefaultCodePage;
+				}
+			}
+		}
+
+		/// <summary>
+		/// Convert a portion of a byte array to a string using <see cref="CodePage"/>
+		/// </summary>
+		/// <param name="data">
+		/// Data to convert to string
+		/// </param>
+		/// <param name="count">
+		/// Number of bytes to convert starting from index 0
+		/// </param>
+		/// <returns>
+		/// data[0]..data[count - 1] converted to a string
+		/// </returns>
+		public static string ConvertToString(byte[] data, int count)
+			=> data == null
+			? string.Empty
+			: Encoding.GetEncoding(CodePage).GetString(data, 0, count);
+
+		/// <summary>
+		/// Convert a byte array to a string using <see cref="CodePage"/>
+		/// </summary>
+		/// <param name="data">
+		/// Byte array to convert
+		/// </param>
+		/// <returns>
+		/// <paramref name="data">data</paramref>converted to a string
+		/// </returns>
+		public static string ConvertToString(byte[] data)
+			=> ConvertToString(data, data.Length);
+
+		private static Encoding EncodingFromFlag(int flags)
+			=> ((flags & (int)GeneralBitFlags.UnicodeText) != 0)
+				? Encoding.UTF8
+				: Encoding.GetEncoding(
+					// if CodePage wasn't set manually and no utf flag present
+					// then we must use SystemDefault (old behavior)
+					// otherwise, CodePage should be preferred over SystemDefault
+					// see https://github.com/icsharpcode/SharpZipLib/issues/274
+					codePage == AutomaticCodePage? 
+						SystemDefaultCodePage:
+						codePage);
+
+		/// <summary>
+		/// Convert a byte array to a string  using <see cref="CodePage"/>
+		/// </summary>
+		/// <param name="flags">The applicable general purpose bits flags</param>
+		/// <param name="data">
+		/// Byte array to convert
+		/// </param>
+		/// <param name="count">The number of bytes to convert.</param>
+		/// <returns>
+		/// <paramref name="data">data</paramref>converted to a string
+		/// </returns>
+		public static string ConvertToStringExt(int flags, byte[] data, int count)
+			=> (data == null)
+				? string.Empty
+				: EncodingFromFlag(flags).GetString(data, 0, count);
+
+		/// <summary>
+		/// Convert a byte array to a string using <see cref="CodePage"/>
+		/// </summary>
+		/// <param name="data">
+		/// Byte array to convert
+		/// </param>
+		/// <param name="flags">The applicable general purpose bits flags</param>
+		/// <returns>
+		/// <paramref name="data">data</paramref>converted to a string
+		/// </returns>
+		public static string ConvertToStringExt(int flags, byte[] data)
+			=> ConvertToStringExt(flags, data, data.Length);
+
+		/// <summary>
+		/// Convert a string to a byte array using <see cref="CodePage"/>
+		/// </summary>
+		/// <param name="str">
+		/// String to convert to an array
+		/// </param>
+		/// <returns>Converted array</returns>
+		public static byte[] ConvertToArray(string str)
+			=> str == null
+			? new byte[0]
+			: Encoding.GetEncoding(CodePage).GetBytes(str);
+
+		/// <summary>
+		/// Convert a string to a byte array using <see cref="CodePage"/>
+		/// </summary>
+		/// <param name="flags">The applicable <see cref="GeneralBitFlags">general purpose bits flags</see></param>
+		/// <param name="str">
+		/// String to convert to an array
+		/// </param>
+		/// <returns>Converted array</returns>
+		public static byte[] ConvertToArray(int flags, string str)
+			=> (string.IsNullOrEmpty(str))
+				? new byte[0]
+				: EncodingFromFlag(flags).GetBytes(str);
+	}
+}

ImportExport.cs

@@ -0,0 +1,97 @@
+using System;
+using System.IO;
+using ICSharpCode.SharpZipLib.Zip;
+
+namespace dezentrale
+{
+    public class ImportExport
+    {
+        public static bool ZipExport(string outFile, string password = null)
+        {
+            if (!Directory.Exists(Program.config.MemberDirectory))
+            {
+                Console.WriteLine($"Cannot find directory '{Program.config.MemberDirectory}'");
+                return false;
+            }
+            try
+            {
+                // Depending on the directory this could be very large and would require more attention
+                // in a commercial package.
+                string[] filenames = Directory.GetFiles(Program.config.MemberDirectory, "member-*.xml");
+
+                if (File.Exists(outFile))
+                {
+                    string backupName = $"{outFile}.bak";
+                    if (File.Exists(backupName)) File.Delete(backupName);
+                    File.Move(outFile, backupName);
+                }
+
+                // 'using' statements guarantee the stream is closed properly which is a big source
+                // of problems otherwise.  Its exception safe as well which is great.
+                using (ZipOutputStream s = new ZipOutputStream(File.Create(outFile)))
+                {
+/*#if DEBUG
+                    s.SetLevel(0); // 0 - store only to 9 - means best compression
+#else*/
+                    s.SetLevel(9); // 0 - store only to 9 - means best compression
+//#endif
+                    s.Password = password;  //null is a desired value for "no encryption"
+
+                    byte[] buffer = new byte[4096];
+
+                    foreach (string file in filenames)
+                    {
+
+                        // Using GetFileName makes the result compatible with XP
+                        // as the resulting path is not absolute.
+                        var entry = new ZipEntry(Path.GetFileName(file));
+
+                        // Setup the entry data as required.
+
+                        // Crc and size are handled by the library for seakable streams
+                        // so no need to do them here.
+
+                        // Could also use the last write time or similar for the file.
+                        entry.DateTime = DateTime.Now;
+                        s.PutNextEntry(entry);
+
+                        using (FileStream fs = File.OpenRead(file))
+                        {
+
+                            // Using a fixed size buffer here makes no noticeable difference for output
+                            // but keeps a lid on memory usage.
+                            int sourceBytes;
+                            do
+                            {
+                                sourceBytes = fs.Read(buffer, 0, buffer.Length);
+                                s.Write(buffer, 0, sourceBytes);
+                            } while (sourceBytes > 0);
+                        }
+                    }
+
+                    // Finish/Close arent needed strictly as the using statement does this automatically
+
+                    // Finish is important to ensure trailing information for a Zip file is appended.  Without this
+                    // the created file would be invalid.
+                    s.Finish();
+
+                    // Close is important to wrap things up and unlock the file.
+                    s.Close();
+                }
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine($"Exception during processing {ex.Message}");
+
+                // No need to rethrow the exception as for our purposes its handled.
+                return false;
+            }
+
+            return true;
+        }
+        public static bool ZipImport(string inFile, string password = null)
+        {
+            return false;
+        }
+    }
+}

Program.cs

@@ -10,7 +10,7 @@ namespace dezentrale
 {
     public class Program
     {
-        public static uint   VersionNumber { get; private set; } = 0x19052500;
+        public static uint   VersionNumber { get; private set; } = 0x19052700;
         public static string VersionString { get; private set; } = $"{VersionNumber:x}";
 
         public static string AppData = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
@@ -27,6 +27,7 @@ namespace dezentrale
             CommandLine = 0,
             Gui = 1,
             Cronjob = 2,
+            Export = 3,
         }
 
         public static eMode ProgramMode = eMode.Gui;
@@ -60,10 +61,11 @@ namespace dezentrale
                     case "mode":
                         switch(argv.ToLower())
                         {
-                            case "cl":    ProgramMode = eMode.CommandLine; Console.WriteLine($"Setting Mode to {ProgramMode}"); break;
-                            case "gui":   ProgramMode = eMode.Gui;         Console.WriteLine($"Setting Mode to {ProgramMode}"); break;
+                            case "cl":     ProgramMode = eMode.CommandLine; Console.WriteLine($"Setting Mode to {ProgramMode}"); break;
+                            case "gui":    ProgramMode = eMode.Gui;         Console.WriteLine($"Setting Mode to {ProgramMode}"); break;
                             case "cronjob":
-                            case "auto":  ProgramMode = eMode.Cronjob;     Console.WriteLine($"Setting Mode to {ProgramMode}"); break;
+                            case "auto":   ProgramMode = eMode.Cronjob;     Console.WriteLine($"Setting Mode to {ProgramMode}"); break;
+                            case "export": ProgramMode = eMode.Export;      Console.WriteLine($"Setting Mode to {ProgramMode}"); break;
                             default:
                                 Console.WriteLine("Invalid mode.");
                                 printHelp = true;
@@ -138,6 +140,8 @@ namespace dezentrale
                     //Console.WriteLine("Not implemented yet");
                     Cronjob.Run();
                     break;
+                case eMode.Export:
+                    return ImportExport.ZipExport(Path.Combine(DmDirectory, config.ImportExportFile), config.ImportExportPassword) != false ? 0 : 1;
             }
 
             return 0;

dezentrale-members.csproj

@@ -8,7 +8,7 @@
     <OutputType>Exe</OutputType>
     <RootNamespace>dezentrale</RootNamespace>
     <AssemblyName>dezentrale-members</AssemblyName>
-    <TargetFrameworkVersion>v3.5</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
     <TargetFrameworkProfile />
@@ -34,7 +34,7 @@
     <DebugType>full</DebugType>
     <Optimize>false</Optimize>
     <OutputPath>bin\Debug\</OutputPath>
-    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <DefineConstants>TRACE;DEBUG;NET45</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <Prefer32Bit>false</Prefer32Bit>
@@ -44,7 +44,7 @@
     <DebugType>pdbonly</DebugType>
     <Optimize>true</Optimize>
     <OutputPath>bin\Release\</OutputPath>
-    <DefineConstants>TRACE</DefineConstants>
+    <DefineConstants>TRACE;NET45</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <Prefer32Bit>false</Prefer32Bit>
@@ -61,6 +61,76 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Cronjob.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\BZip2\BZip2.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\BZip2\BZip2Constants.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\BZip2\BZip2Exception.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\BZip2\BZip2InputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\BZip2\BZip2OutputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Checksum\Adler32.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Checksum\BZip2Crc.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Checksum\Crc32.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Checksum\IChecksum.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\Exceptions\SharpZipBaseException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\Exceptions\StreamDecodingException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\Exceptions\StreamUnsupportedException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\Exceptions\UnexpectedEndOfStreamException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\Exceptions\ValueOutOfRangeException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\FileSystemScanner.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\INameTransform.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\InvalidNameException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\IScanFilter.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\NameFilter.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\PathFilter.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\StreamUtils.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Core\WindowsPathUtils.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Encryption\PkzipClassic.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Encryption\ZipAESStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Encryption\ZipAESTransform.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\GZip\GZip.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\GZip\GZipConstants.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\GZip\GZipException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\GZip\GzipInputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\GZip\GzipOutputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Lzw\LzwConstants.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Lzw\LzwException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Lzw\LzwInputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\InvalidHeaderException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\TarArchive.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\TarBuffer.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\TarEntry.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\TarException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\TarExtendedHeaderReader.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\TarHeader.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\TarInputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Tar\TarOutputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\Deflater.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\DeflaterConstants.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\DeflaterEngine.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\DeflaterHuffman.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\DeflaterPending.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\Inflater.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\InflaterDynHeader.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\InflaterHuffmanTree.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\PendingBuffer.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\Streams\DeflaterOutputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\Streams\InflaterInputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\Streams\OutputWindow.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\Compression\Streams\StreamManipulator.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\FastZip.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\IEntryFactory.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\WindowsNameTransform.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipConstants.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipEntry.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipEntryFactory.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipException.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipExtraData.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipFile.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipHelperStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipInputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipNameTransform.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipOutputStream.cs" />
+    <Compile Include="ICSharpCode.SharpZipLib\Zip\ZipStrings.cs" />
+    <Compile Include="ImportExport.cs" />
     <Compile Include="model\BankTransfer.cs" />
     <Compile Include="model\BankTransferList.cs" />
     <Compile Include="model\CsvFile.cs" />
@@ -102,5 +172,6 @@
       <Install>true</Install>
     </BootstrapperPackage>
   </ItemGroup>
+  <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
 </Project>

model/Configuration.cs

@@ -8,12 +8,14 @@ namespace dezentrale.model
 {
     public class Configuration : XmlData
     {
-        [XmlElement] public ConfigSmtp Smtp           { get; set; } = new ConfigSmtp();
-        [XmlElement] public ConfigVSMail VS           { get; set; } = new ConfigVSMail();
+        [XmlElement] public ConfigSmtp Smtp             { get; set; } = new ConfigSmtp();
+        [XmlElement] public ConfigVSMail VS             { get; set; } = new ConfigVSMail();
 
-        [XmlElement] public string MemberDirectory    { get; set; } = "member-data";
-        [XmlElement] public uint RegularPaymentAmount { get; set; } = 3200; //cents
-        [XmlElement] public string LocalUser          { get; set; } = "";
-        [XmlElement] public string KeylockCombination { get; set; } = "0000";
+        [XmlElement] public string MemberDirectory      { get; set; } = "member-data";
+        [XmlElement] public uint RegularPaymentAmount   { get; set; } = 3200; //cents
+        [XmlElement] public string LocalUser            { get; set; } = "";
+        [XmlElement] public string KeylockCombination   { get; set; } = "0000";
+        [XmlElement] public string ImportExportFile     { get; set; } = "fnord.fnord";
+        [XmlElement] public string ImportExportPassword { get; set; } = null;
     }
 }