// 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 Interop=System.Runtime.InteropServices;
namespace Ionic.Zlib
{
/// <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>
/// An enum to specify the direction of transcoding - whether to compress or decompress.
/// </summary>
public enum CompressionMode
{
/// <summary>
/// Used to specify that the stream should compress the data.
/// </summary>
Compress= 0,
/// <summary>
/// Used to specify that the stream should decompress the data.
/// </summary>
Decompress = 1,
}
/// <summary>
/// A general purpose exception class for exceptions in the Zlib library.
/// </summary>
[Interop.GuidAttribute("ebc25cf6-9120-4283-b972-0e5520d0000E")]
public class ZlibException : System.Exception
{
/// <summary>
/// The ZlibException class captures exception information generated
/// by the Zlib library.
/// </summary>
public ZlibException()
: base()
{
}
/// <summary>
/// This ctor collects a message attached to the exception.
/// </summary>
/// <param name="s"></param>
public ZlibException(System.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 System.Int32 ReadInput(System.IO.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 byte[] ToByteArray(System.String sourceString)
{
return System.Text.UTF8Encoding.UTF8.GetBytes(sourceString);
}
internal static char[] ToCharArray(byte[] byteArray)
{
return System.Text.UTF8Encoding.UTF8.GetChars(byteArray);
}
}
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 = new short[] {
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 = new short[] {
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 };
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, Tree.ExtraLengthBits, InternalConstants.LITERALS + 1, InternalConstants.L_CODES, InternalConstants.MAX_BITS);
Distances = new StaticTree(distTreeCodes, Tree.ExtraDistanceBits, 0, InternalConstants.D_CODES, InternalConstants.MAX_BITS);
BitLengths = new StaticTree(null, Tree.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 int BASE = 65521;
// NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1
private static readonly int NMAX = 5552;
static internal uint Adler32(uint adler, byte[] buf, int index, int len)
{
if (buf == null)
return 1;
int s1 = (int) (adler & 0xffff);
int s2 = (int) ((adler >> 16) & 0xffff);
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 (uint)((s2 << 16) | s1);
}
}
}
Submit an article or tip