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- // Zlib.cs
- // ------------------------------------------------------------------
- //
- // Copyright (c) 2009 Dino Chiesa and Microsoft Corporation.
- // All rights reserved.
- //
- // This code module is part of DotNetZip, a zipfile class library.
- //
- // ------------------------------------------------------------------
- //
- // This code is licensed under the Microsoft Public License.
- // See the file License.txt for the license details.
- // More info on: http://dotnetzip.codeplex.com
- //
- // ------------------------------------------------------------------
- //
- // last saved (in emacs):
- // Time-stamp: <2009-November-07 05:26:55>
- //
- // ------------------------------------------------------------------
- //
- // This module defines classes for ZLIB compression and
- // decompression. This code is derived from the jzlib implementation of
- // zlib, but significantly modified. The object model is not the same,
- // and many of the behaviors are new or different. Nonetheless, in
- // keeping with the license for jzlib, the copyright to that code is
- // included below.
- //
- // ------------------------------------------------------------------
- //
- // Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved.
- //
- // Redistribution and use in source and binary forms, with or without
- // modification, are permitted provided that the following conditions are met:
- //
- // 1. Redistributions of source code must retain the above copyright notice,
- // this list of conditions and the following disclaimer.
- //
- // 2. Redistributions in binary form must reproduce the above copyright
- // notice, this list of conditions and the following disclaimer in
- // the documentation and/or other materials provided with the distribution.
- //
- // 3. The names of the authors may not be used to endorse or promote products
- // derived from this software without specific prior written permission.
- //
- // THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
- // INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
- // FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
- // INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
- // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
- // OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
- // EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- //
- // -----------------------------------------------------------------------
- //
- // This program is based on zlib-1.1.3; credit to authors
- // Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu)
- // and contributors of zlib.
- //
- // -----------------------------------------------------------------------
- using System;
- using System.IO;
- namespace SharpCompress.Compressors.Deflate
- {
- /// <summary>
- /// The compression level to be used when using a DeflateStream or ZlibStream with CompressionMode.Compress.
- /// </summary>
- public enum CompressionLevel
- {
- /// <summary>
- /// None means that the data will be simply stored, with no change at all.
- /// If you are producing ZIPs for use on Mac OSX, be aware that archives produced with CompressionLevel.None
- /// cannot be opened with the default zip reader. Use a different CompressionLevel.
- /// </summary>
- None = 0,
- /// <summary>
- /// Same as None.
- /// </summary>
- Level0 = 0,
- /// <summary>
- /// The fastest but least effective compression.
- /// </summary>
- BestSpeed = 1,
- /// <summary>
- /// A synonym for BestSpeed.
- /// </summary>
- Level1 = 1,
- /// <summary>
- /// A little slower, but better, than level 1.
- /// </summary>
- Level2 = 2,
- /// <summary>
- /// A little slower, but better, than level 2.
- /// </summary>
- Level3 = 3,
- /// <summary>
- /// A little slower, but better, than level 3.
- /// </summary>
- Level4 = 4,
- /// <summary>
- /// A little slower than level 4, but with better compression.
- /// </summary>
- Level5 = 5,
- /// <summary>
- /// The default compression level, with a good balance of speed and compression efficiency.
- /// </summary>
- Default = 6,
- /// <summary>
- /// A synonym for Default.
- /// </summary>
- Level6 = 6,
- /// <summary>
- /// Pretty good compression!
- /// </summary>
- Level7 = 7,
- /// <summary>
- /// Better compression than Level7!
- /// </summary>
- Level8 = 8,
- /// <summary>
- /// The "best" compression, where best means greatest reduction in size of the input data stream.
- /// This is also the slowest compression.
- /// </summary>
- BestCompression = 9,
- /// <summary>
- /// A synonym for BestCompression.
- /// </summary>
- Level9 = 9
- }
- /// <summary>
- /// Describes options for how the compression algorithm is executed. Different strategies
- /// work better on different sorts of data. The strategy parameter can affect the compression
- /// ratio and the speed of compression but not the correctness of the compresssion.
- /// </summary>
- public enum CompressionStrategy
- {
- /// <summary>
- /// The default strategy is probably the best for normal data.
- /// </summary>
- Default = 0,
- /// <summary>
- /// The <c>Filtered</c> strategy is intended to be used most effectively with data produced by a
- /// filter or predictor. By this definition, filtered data consists mostly of small
- /// values with a somewhat random distribution. In this case, the compression algorithm
- /// is tuned to compress them better. The effect of <c>Filtered</c> is to force more Huffman
- /// coding and less string matching; it is a half-step between <c>Default</c> and <c>HuffmanOnly</c>.
- /// </summary>
- Filtered = 1,
- /// <summary>
- /// Using <c>HuffmanOnly</c> will force the compressor to do Huffman encoding only, with no
- /// string matching.
- /// </summary>
- HuffmanOnly = 2
- }
- /// <summary>
- /// A general purpose exception class for exceptions in the Zlib library.
- /// </summary>
- public class ZlibException : Exception
- {
- /// <summary>
- /// The ZlibException class captures exception information generated
- /// by the Zlib library.
- /// </summary>
- public ZlibException()
- {
- }
- /// <summary>
- /// This ctor collects a message attached to the exception.
- /// </summary>
- /// <param name="s"></param>
- public ZlibException(String s)
- : base(s)
- {
- }
- }
- internal class SharedUtils
- {
- /// <summary>
- /// Performs an unsigned bitwise right shift with the specified number
- /// </summary>
- /// <param name="number">Number to operate on</param>
- /// <param name="bits">Ammount of bits to shift</param>
- /// <returns>The resulting number from the shift operation</returns>
- public static int URShift(int number, int bits)
- {
- return (int)((uint)number >> bits);
- }
- #if NOT
- /// <summary>
- /// Performs an unsigned bitwise right shift with the specified number
- /// </summary>
- /// <param name="number">Number to operate on</param>
- /// <param name="bits">Ammount of bits to shift</param>
- /// <returns>The resulting number from the shift operation</returns>
- public static long URShift(long number, int bits)
- {
- return (long) ((UInt64)number >> bits);
- }
- #endif
- /// <summary>
- /// Reads a number of characters from the current source TextReader and writes
- /// the data to the target array at the specified index.
- /// </summary>
- ///
- /// <param name="sourceTextReader">The source TextReader to read from</param>
- /// <param name="target">Contains the array of characteres read from the source TextReader.</param>
- /// <param name="start">The starting index of the target array.</param>
- /// <param name="count">The maximum number of characters to read from the source TextReader.</param>
- ///
- /// <returns>
- /// The number of characters read. The number will be less than or equal to
- /// count depending on the data available in the source TextReader. Returns -1
- /// if the end of the stream is reached.
- /// </returns>
- public static Int32 ReadInput(TextReader sourceTextReader, byte[] target, int start, int count)
- {
- // Returns 0 bytes if not enough space in target
- if (target.Length == 0)
- {
- return 0;
- }
- char[] charArray = new char[target.Length];
- int bytesRead = sourceTextReader.Read(charArray, start, count);
- // Returns -1 if EOF
- if (bytesRead == 0)
- {
- return -1;
- }
- for (int index = start; index < start + bytesRead; index++)
- {
- target[index] = (byte)charArray[index];
- }
- return bytesRead;
- }
- }
- internal static class InternalConstants
- {
- internal static readonly int MAX_BITS = 15;
- internal static readonly int BL_CODES = 19;
- internal static readonly int D_CODES = 30;
- internal static readonly int LITERALS = 256;
- internal static readonly int LENGTH_CODES = 29;
- internal static readonly int L_CODES = (LITERALS + 1 + LENGTH_CODES);
- // Bit length codes must not exceed MAX_BL_BITS bits
- internal static readonly int MAX_BL_BITS = 7;
- // repeat previous bit length 3-6 times (2 bits of repeat count)
- internal static readonly int REP_3_6 = 16;
- // repeat a zero length 3-10 times (3 bits of repeat count)
- internal static readonly int REPZ_3_10 = 17;
- // repeat a zero length 11-138 times (7 bits of repeat count)
- internal static readonly int REPZ_11_138 = 18;
- }
- internal sealed class StaticTree
- {
- internal static readonly short[] lengthAndLiteralsTreeCodes =
- {
- 12, 8, 140, 8, 76, 8, 204, 8, 44, 8, 172,
- 8, 108, 8, 236, 8,
- 28, 8, 156, 8, 92, 8, 220, 8, 60, 8, 188,
- 8, 124, 8, 252, 8,
- 2, 8, 130, 8, 66, 8, 194, 8, 34, 8, 162, 8
- , 98, 8, 226, 8,
- 18, 8, 146, 8, 82, 8, 210, 8, 50, 8, 178,
- 8, 114, 8, 242, 8,
- 10, 8, 138, 8, 74, 8, 202, 8, 42, 8, 170,
- 8, 106, 8, 234, 8,
- 26, 8, 154, 8, 90, 8, 218, 8, 58, 8, 186,
- 8, 122, 8, 250, 8,
- 6, 8, 134, 8, 70, 8, 198, 8, 38, 8, 166, 8
- , 102, 8, 230, 8,
- 22, 8, 150, 8, 86, 8, 214, 8, 54, 8, 182,
- 8, 118, 8, 246, 8,
- 14, 8, 142, 8, 78, 8, 206, 8, 46, 8, 174,
- 8, 110, 8, 238, 8,
- 30, 8, 158, 8, 94, 8, 222, 8, 62, 8, 190,
- 8, 126, 8, 254, 8,
- 1, 8, 129, 8, 65, 8, 193, 8, 33, 8, 161, 8
- , 97, 8, 225, 8,
- 17, 8, 145, 8, 81, 8, 209, 8, 49, 8, 177,
- 8, 113, 8, 241, 8,
- 9, 8, 137, 8, 73, 8, 201, 8, 41, 8, 169, 8
- , 105, 8, 233, 8,
- 25, 8, 153, 8, 89, 8, 217, 8, 57, 8, 185,
- 8, 121, 8, 249, 8,
- 5, 8, 133, 8, 69, 8, 197, 8, 37, 8, 165, 8
- , 101, 8, 229, 8,
- 21, 8, 149, 8, 85, 8, 213, 8, 53, 8, 181,
- 8, 117, 8, 245, 8,
- 13, 8, 141, 8, 77, 8, 205, 8, 45, 8, 173,
- 8, 109, 8, 237, 8,
- 29, 8, 157, 8, 93, 8, 221, 8, 61, 8, 189,
- 8, 125, 8, 253, 8,
- 19, 9, 275, 9, 147, 9, 403, 9, 83, 9, 339,
- 9, 211, 9, 467, 9,
- 51, 9, 307, 9, 179, 9, 435, 9, 115, 9, 371
- , 9, 243, 9, 499, 9,
- 11, 9, 267, 9, 139, 9, 395, 9, 75, 9, 331,
- 9, 203, 9, 459, 9,
- 43, 9, 299, 9, 171, 9, 427, 9, 107, 9, 363
- , 9, 235, 9, 491, 9,
- 27, 9, 283, 9, 155, 9, 411, 9, 91, 9, 347,
- 9, 219, 9, 475, 9,
- 59, 9, 315, 9, 187, 9, 443, 9, 123, 9, 379
- , 9, 251, 9, 507, 9,
- 7, 9, 263, 9, 135, 9, 391, 9, 71, 9, 327,
- 9, 199, 9, 455, 9,
- 39, 9, 295, 9, 167, 9, 423, 9, 103, 9, 359
- , 9, 231, 9, 487, 9,
- 23, 9, 279, 9, 151, 9, 407, 9, 87, 9, 343,
- 9, 215, 9, 471, 9,
- 55, 9, 311, 9, 183, 9, 439, 9, 119, 9, 375
- , 9, 247, 9, 503, 9,
- 15, 9, 271, 9, 143, 9, 399, 9, 79, 9, 335,
- 9, 207, 9, 463, 9,
- 47, 9, 303, 9, 175, 9, 431, 9, 111, 9, 367
- , 9, 239, 9, 495, 9,
- 31, 9, 287, 9, 159, 9, 415, 9, 95, 9, 351,
- 9, 223, 9, 479, 9,
- 63, 9, 319, 9, 191, 9, 447, 9, 127, 9, 383
- , 9, 255, 9, 511, 9,
- 0, 7, 64, 7, 32, 7, 96, 7, 16, 7, 80, 7,
- 48, 7, 112, 7,
- 8, 7, 72, 7, 40, 7, 104, 7, 24, 7, 88, 7,
- 56, 7, 120, 7,
- 4, 7, 68, 7, 36, 7, 100, 7, 20, 7, 84, 7,
- 52, 7, 116, 7,
- 3, 8, 131, 8, 67, 8, 195, 8, 35, 8, 163, 8
- , 99, 8, 227, 8
- };
- internal static readonly short[] distTreeCodes =
- {
- 0, 5, 16, 5, 8, 5, 24, 5, 4, 5, 20, 5, 12, 5, 28, 5,
- 2, 5, 18, 5, 10, 5, 26, 5, 6, 5, 22, 5, 14, 5, 30, 5,
- 1, 5, 17, 5, 9, 5, 25, 5, 5, 5, 21, 5, 13, 5, 29, 5,
- 3, 5, 19, 5, 11, 5, 27, 5, 7, 5, 23, 5
- };
- // extra bits for each bit length code
- internal static readonly int[] extra_blbits = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7};
- internal static readonly StaticTree Literals;
- internal static readonly StaticTree Distances;
- internal static readonly StaticTree BitLengths;
- internal short[] treeCodes; // static tree or null
- internal int[] extraBits; // extra bits for each code or null
- internal int extraBase; // base index for extra_bits
- internal int elems; // max number of elements in the tree
- internal int maxLength; // max bit length for the codes
- private StaticTree(short[] treeCodes, int[] extraBits, int extraBase, int elems, int maxLength)
- {
- this.treeCodes = treeCodes;
- this.extraBits = extraBits;
- this.extraBase = extraBase;
- this.elems = elems;
- this.maxLength = maxLength;
- }
- static StaticTree()
- {
- Literals = new StaticTree(lengthAndLiteralsTreeCodes, DeflateManager.ExtraLengthBits,
- InternalConstants.LITERALS + 1, InternalConstants.L_CODES,
- InternalConstants.MAX_BITS);
- Distances = new StaticTree(distTreeCodes, DeflateManager.ExtraDistanceBits, 0, InternalConstants.D_CODES,
- InternalConstants.MAX_BITS);
- BitLengths = new StaticTree(null, extra_blbits, 0, InternalConstants.BL_CODES, InternalConstants.MAX_BL_BITS);
- }
- }
- /// <summary>
- /// Computes an Adler-32 checksum.
- /// </summary>
- /// <remarks>
- /// The Adler checksum is similar to a CRC checksum, but faster to compute, though less
- /// reliable. It is used in producing RFC1950 compressed streams. The Adler checksum
- /// is a required part of the "ZLIB" standard. Applications will almost never need to
- /// use this class directly.
- /// </remarks>
- internal sealed class Adler
- {
- // largest prime smaller than 65536
- private static readonly uint BASE = 65521U;
- // NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1
- private static readonly int NMAX = 5552;
- internal static uint Adler32(uint adler, byte[] buf, int index, int len)
- {
- if (buf == null)
- {
- return 1;
- }
- uint s1 = adler & 0xffffU;
- uint s2 = (adler >> 16) & 0xffffU;
- while (len > 0)
- {
- int k = len < NMAX ? len : NMAX;
- len -= k;
- while (k >= 16)
- {
- //s1 += (buf[index++] & 0xff); s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- k -= 16;
- }
- if (k != 0)
- {
- do
- {
- s1 += buf[index++];
- s2 += s1;
- }
- while (--k != 0);
- }
- s1 %= BASE;
- s2 %= BASE;
- }
- return (s2 << 16) | s1;
- }
- }
- }
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