535 lines
17 KiB
C#
535 lines
17 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using UniversalEditor.Compression.Modules.Explode.Internal;
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namespace UniversalEditor.Compression.Modules.Explode
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{
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public class ExplodeCompressionModule : CompressionModule
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{
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public override string Name
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{
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get { return "Explode"; }
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}
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protected override void CompressInternal(System.IO.Stream inputStream, System.IO.Stream outputStream)
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{
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throw new NotImplementedException();
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}
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protected override void DecompressInternal(System.IO.Stream inputStream, System.IO.Stream outputStream, int inputLength, int outputLength)
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{
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Ptr<byte> _ptrOut = new Ptr<byte>();
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_ptrOut.AutoResize = true;
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this.blast(inputStream, outputStream, _ptrOut, 0);
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}
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private uint _explodeInput(object how, ref Ptr<byte> buf)
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{
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return 0;
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}
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private int _explodeOutput(object how, Ptr<byte> buf, uint len)
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{
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return 0;
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}
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// translated to C# for Universal Editor by Michael Becker
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// modified by Luigi Auriemma because if MAXWIN is the standard 4096 then not all the data is decompressed
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/* blast.c
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* Copyright (C) 2003 Mark Adler
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* version 1.1, 16 Feb 2003
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the author be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*
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* Mark Adler madler@alumni.caltech.edu
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*
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* blast.c decompresses data compressed by the PKWare Compression Library.
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* This function provides functionality similar to the explode() function of
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* the PKWare library, hence the name "blast".
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*
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* This decompressor is based on the excellent format description provided by
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* Ben Rudiak-Gould in comp.compression on August 13, 2001. Interestingly, the
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* example Ben provided in the post is incorrect. The distance 110001 should
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* instead be 111000. When corrected, the example byte stream becomes:
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*
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* 00 04 82 24 25 8f 80 7f
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*
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* which decompresses to "AIAIAIAIAIAIA" (without the quotes).
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*/
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/*
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* Change history:
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*
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* 1.0 12 Feb 2003 - First version
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* 1.1 16 Feb 2003 - Fixed distance check for > 4 GB uncompressed data
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*/
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/// <summary>
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/// Maximum code length
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/// </summary>
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private const int MAXBITS = 13;
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/*
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* Return need bits from the input stream. This always leaves less than
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* eight bits in the buffer. bits() works properly for need == 0.
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*
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* Format notes:
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*
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* - Bits are stored in bytes from the least significant bit to the most
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* significant bit. Therefore bits are dropped from the bottom of the bit
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* buffer, using shift right, and new bytes are appended to the top of the
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* bit buffer, using shift left.
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*/
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private static int bits(ExplodeState s, int need)
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{
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// bit accumulator
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int val;
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// load at least need bits into val
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val = s.bitbuf;
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while (s.bitcnt < need)
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{
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if (s.left == 0)
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{
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readInput(ref s);
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}
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val |= (int)(s.indata.GetValueThenIncrement() << s.bitcnt); // load eight bits
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s.left--;
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s.bitcnt += 8;
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}
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// drop need bits and update buffer, always zero to seven bits left
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s.bitbuf = val >> need;
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s.bitcnt -= need;
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// return need bits, zeroing the bits above that
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return val & ((1 << need) - 1);
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}
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private static void readInput(ref ExplodeState s)
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{
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byte[] tmpBuffer = new byte[4096];
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s.left = (uint)s.inputStream.Read(tmpBuffer, 0, tmpBuffer.Length);
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byte[] buffer = s.indata.ToArray();
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if (buffer.Length < s.left)
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{
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}
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if (s.left == 0) throw new OutOfInputException();
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}
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/*
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* Format notes:
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*
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* - The codes as stored in the compressed data are bit-reversed relative to
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* a simple integer ordering of codes of the same lengths. Hence below the
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* bits are pulled from the compressed data one at a time and used to
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* build the code value reversed from what is in the stream in order to
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* permit simple integer comparisons for decoding.
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*
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* - The first code for the shortest length is all ones. Subsequent codes of
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* the same length are simply integer decrements of the previous code. When
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* moving up a length, a one bit is appended to the code. For a complete
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* code, the last code of the longest length will be all zeros. To support
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* this ordering, the bits pulled during decoding are inverted to apply the
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* more "natural" ordering starting with all zeros and incrementing.
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*/
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/// <summary>
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/// Decode a code from the stream s using huffman table h.
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/// </summary>
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/// <param name="s"></param>
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/// <param name="h"></param>
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/// <returns>
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/// The decoded symbol, or a negative value if there is an error. If all of the lengths are
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/// zero (i.e. an empty code), or if the code is incomplete and an invalid code is received,
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/// then -9 is returned after reading MAXBITS bits.
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/// </returns>
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private static int decode(ExplodeState s, ref ExplodeHuffman h)
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{
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int len; /* current number of bits in code */
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int code; /* len bits being decoded */
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int first; /* first code of length len */
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int count; /* number of codes of length len */
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int count_ptr = 0;
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int index; /* index of first code of length len in symbol table */
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int bitbuf; /* bits from stream */
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int left; /* bits left in next or left to process */
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Ptr<short> next; // next number of codes
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bitbuf = s.bitbuf;
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left = s.bitcnt;
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code = first = index = 0;
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len = 1;
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next = h.count + 1;
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while (true)
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{
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while (left-- != 0)
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{
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code |= (bitbuf & 1) ^ 1; /* invert code */
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bitbuf >>= 1;
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count = next.GetValueThenIncrement();
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if (code < first + count)
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{
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// if length len, return symbol
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s.bitbuf = bitbuf;
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s.bitcnt = (s.bitcnt - len) & 7;
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return h.symbol[index + (code - first)];
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}
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index += count; /* else update for next length */
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first += count;
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first <<= 1;
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code <<= 1;
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len++;
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}
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left = (MAXBITS+1) - len;
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if (left == 0) break;
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if (s.left == 0)
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{
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readInput(ref s);
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if (s.left == 0) throw new OutOfInputException();
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}
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bitbuf = s.indata.GetValue() + 1; // *(s.in)++;
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s.left--;
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if (left > 8) left = 8;
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}
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return -9; /* ran out of codes */
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}
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/// <summary>
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/// Given a list of repeated code lengths rep[0..n-1], where each byte is a count (high four
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/// bits + 1) and a code length (low four bits), generate the list of code lengths. This
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/// compaction reduces the size of the object code. Then given the list of code lengths
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/// length[0..n-1] representing a canonical Huffman code for n symbols, construct the
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/// tables required to decode those codes. Those tables are the number of codes of each
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/// length, and the symbols sorted by length, retaining their original order within each
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/// length.
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/// </summary>
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/// <param name="h"></param>
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/// <param name="rep"></param>
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/// <returns>
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/// Zero for a complete code set, negative for an over-subscribed code set, and positive for an incomplete code set.
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/// </returns>
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/// <remarks>
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/// The tables can be used if the return value is zero or positive, but they cannot be used
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/// if the return value is negative. If the return value is zero, it is not possible for
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/// decode() using that table to return an error--any stream of enough bits will resolve to
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/// a symbol. If the return value is positive, then it is possible for decode() using that
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/// table to return an error for received codes past the end of the incomplete lengths.
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/// </remarks>
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private static int construct(ref ExplodeHuffman h, byte[] rep)
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{
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int n = rep.Length;
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int symbol; // current symbol when stepping through length[]
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int len; // current length when stepping through h.count[]
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int left; // number of possible codes left of current length
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short[] offs = new short[MAXBITS + 1]; // offsets in symbol table for each length
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short[] length = new short[256]; // code lengths
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Ptr<byte> repP = new Ptr<byte>(rep);
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// convert compact repeat counts into symbol bit length list
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symbol = 0;
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do
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{
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len = repP.GetValueThenIncrement(); // *rep++
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left = (len >> 4) + 1;
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len &= 15;
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do
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{
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length[symbol++] = (short)len;
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}
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while (--left != 0);
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}
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while (--n != 0);
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n = symbol;
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// count number of codes of each length
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for (len = 0; len <= MAXBITS; len++)
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h.count[len] = 0;
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for (symbol = 0; symbol < n; symbol++)
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{
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(h.count[length[symbol]])++; // assumes lengths are within bounds
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}
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if (h.count[0] == n)
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{
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// no codes!
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return 0; // complete, but decode() will fail
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}
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// check for an over-subscribed or incomplete set of lengths
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left = 1; // one possible code of zero length
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for (len = 1; len <= MAXBITS; len++)
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{
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left <<= 1; // one more bit, double codes left
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left -= h.count[len]; // deduct count from possible codes
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if (left < 0) return left; // over-subscribed--return negative
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} // left > 0 means incomplete
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// generate offsets into symbol table for each length for sorting
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offs[1] = 0;
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for (len = 1; len < MAXBITS; len++)
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{
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offs[len + 1] = (short)(offs[len] + h.count[len]); // h.count[len]
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}
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// put symbols in table sorted by length, by symbol order within each length
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for (symbol = 0; symbol < n; symbol++)
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{
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if (length[symbol] != 0)
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{
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h.symbol[offs[length[symbol]]++] = (short)symbol;
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}
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}
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// return zero for complete set, positive for incomplete set
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return left;
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}
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private static bool virgin = true; // build tables once
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private static short[] litcnt = new short[MAXBITS + 1],
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litsym = new short[256]; // litcode memory
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private static short[] lencnt = new short[MAXBITS + 1],
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lensym = new short[16]; // lencode memory
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private static short[] distcnt = new short[MAXBITS + 1],
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distsym = new short[64]; // distcode memory
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/// <summary>
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/// Literal code
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/// </summary>
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private static ExplodeHuffman litcode = new ExplodeHuffman()
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{
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count = new Ptr<short>(litcnt),
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symbol = new Ptr<short>(litsym)
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};
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/// <summary>
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/// Length code
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/// </summary>
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private static ExplodeHuffman lencode = new ExplodeHuffman()
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{
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count = new Ptr<short>(lencnt),
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symbol = new Ptr<short>(lensym)
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};
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/// <summary>
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/// Distance code
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/// </summary>
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private static ExplodeHuffman distcode = new ExplodeHuffman()
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{
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count = new Ptr<short>(distcnt),
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symbol = new Ptr<short>(distsym)
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};
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// bit lengths of literal codes
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private static readonly byte[] litlen = new byte[]
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{
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11, 124, 8, 7, 28, 7, 188, 13, 76, 4, 10, 8, 12, 10, 12, 10, 8, 23, 8,
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9, 7, 6, 7, 8, 7, 6, 55, 8, 23, 24, 12, 11, 7, 9, 11, 12, 6, 7, 22, 5,
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7, 24, 6, 11, 9, 6, 7, 22, 7, 11, 38, 7, 9, 8, 25, 11, 8, 11, 9, 12,
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8, 12, 5, 38, 5, 38, 5, 11, 7, 5, 6, 21, 6, 10, 53, 8, 7, 24, 10, 27,
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44, 253, 253, 253, 252, 252, 252, 13, 12, 45, 12, 45, 12, 61, 12, 45,
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44, 173
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};
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/// <summary>
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/// Bit lengths of length codes 0..15
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/// </summary>
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private static readonly byte[] lenlen = new byte[] { 2, 35, 36, 53, 38, 23 };
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/// <summary>
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/// Bit lengths of distance codes 0..63
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/// </summary>
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private static readonly byte[] distlen = new byte[] { 2, 20, 53, 230, 247, 151, 248 };
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/// <summary>
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/// Base for length codes
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/// </summary>
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private static readonly short[] _base = new short[] { 3, 2, 4, 5, 6, 7, 8, 9, 10, 12, 16, 24, 40, 72, 136, 264 };
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/// <summary>
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/// Extra bits for length codes
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/// </summary>
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private static readonly byte[] extra = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8 };
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/*
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* Format notes:
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*
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* - First byte is 0 if literals are uncoded or 1 if they are coded. Second
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* byte is 4, 5, or 6 for the number of extra bits in the distance code.
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* This is the base-2 logarithm of the dictionary size minus six.
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*
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* - Compressed data is a combination of literals and length/distance pairs
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* terminated by an end code. Literals are either Huffman coded or
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* uncoded bytes. A length/distance pair is a coded length followed by a
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* coded distance to represent a string that occurs earlier in the
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* uncompressed data that occurs again at the current location.
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*
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* - A bit preceding a literal or length/distance pair indicates which comes
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* next, 0 for literals, 1 for length/distance.
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*
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* - If literals are uncoded, then the next eight bits are the literal, in the
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* normal bit order in th stream, i.e. no bit-reversal is needed. Similarly,
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* no bit reversal is needed for either the length extra bits or the distance
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* extra bits.
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*
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* - Literal bytes are simply written to the output. A length/distance pair is
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* an instruction to copy previously uncompressed bytes to the output. The
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* copy is from distance bytes back in the output stream, copying for length
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* bytes.
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*
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* - Distances pointing before the beginning of the output data are not
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* permitted.
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*
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* - Overlapped copies, where the length is greater than the distance, are
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* allowed and common. For example, a distance of one and a length of 518
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* simply copies the last byte 518 times. A distance of four and a length of
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* twelve copies the last four bytes three times. A simple forward copy
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* ignoring whether the length is greater than the distance or not implements
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* this correctly.
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*/
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private static object virginity = new object();
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/// <summary>
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/// Decode PKWare Compression Library stream.
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/// </summary>
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/// <param name="s"></param>
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/// <returns></returns>
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private static int decomp(ref ExplodeState s)
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{
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int lit; /* true if literals are coded */
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int dict; /* log2(dictionary size) - 6 */
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int symbol; /* decoded symbol, extra bits for distance */
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int len; /* length for copy */
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int dist; /* distance for copy */
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int copy; /* copy counter */
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Ptr<byte> from, to; /* copy pointers */
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// set up decoding tables (once--might not be thread-safe)
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lock (virginity)
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{
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if (virgin)
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{
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construct(ref litcode, litlen);
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construct(ref lencode, lenlen);
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construct(ref distcode, distlen);
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virgin = false;
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}
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}
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// read header
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lit = bits(s, 8);
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if (lit > 1) return -1;
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dict = bits(s, 8);
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if (dict < 4 || dict > 6) return -2;
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// decode literals and length/distance pairs
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do
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{
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if (bits(s, 1) != 0)
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{
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// get length
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symbol = decode(s, ref lencode);
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len = _base[symbol] + bits(s, extra[symbol]);
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if (len == 519) break; // end code
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// get distance
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symbol = len == 2 ? 2 : dict;
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dist = decode(s, ref distcode) << symbol;
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dist += bits(s, symbol);
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dist++;
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if (s.first != 0 && dist > s.next)
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{
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throw new ArgumentOutOfRangeException("distance too far back");
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}
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// copy length bytes from distance bytes back
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do
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{
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to = s.outdata + s.next;
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from = to - dist;
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copy = -1;
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if (s.next < dist)
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{
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from += copy;
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copy = dist;
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}
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copy -= s.next;
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if (copy > len) copy = len;
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len -= copy;
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s.next += copy;
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do
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{
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to.SetValueThenIncrement(from.GetValueThenIncrement());
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}
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while (--copy != 0);
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if (s.next == -1)
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{
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s.outputStream.Write(s.outdata.ToArray());
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s.next = 0;
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s.first = 0;
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}
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} while (len != 0);
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}
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else
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{
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// get literal and write it
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symbol = (lit != 0) ? decode(s, ref litcode) : bits(s, 8);
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s.outdata.SetValueThenIncrement((byte)symbol);
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if (s.next == -1)
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{
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s.outputStream.Write(s.outdata.ToArray());
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s.next = 0;
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s.first = 0;
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}
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}
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}
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while (true);
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return 0;
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}
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void blast(System.IO.Stream inputStream, System.IO.Stream outputStream, Ptr<byte> outdata, int outsz)
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{
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ExplodeState s = new ExplodeState(); // input/output state
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// initialize input state
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s.inputStream = inputStream;
|
|
s.left = 0;
|
|
s.bitbuf = 0;
|
|
s.bitcnt = 0;
|
|
s.indata = new Ptr<byte>(new byte[0]);
|
|
|
|
// initialize output state
|
|
s.outputStream = outputStream;
|
|
s.next = 0;
|
|
s.first = 1;
|
|
s.outdata = new Ptr<byte>(new byte[0]);
|
|
|
|
// decompress
|
|
decomp(ref s);
|
|
|
|
// write any leftover output
|
|
if (s.outdata.Size > 0) s.outputStream.Write(s.outdata.ToArray());
|
|
}
|
|
|
|
}
|
|
}
|