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e818a322ac
* Decode short codes at the end of the inflate input InflateCodes waited for as many bits as its lookup table uses before it decoded a literal, length or distance code. When the input ended with fewer bits than that, the last codes were not decoded, even though they were complete. An MS-ZIP block is a deflate stream on its own, so its last match was lost and the block came out short (#1). When no more input is there, the code is now looked up with the bits that are left and used if it is not longer than those. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> * Keep a full 32 KiB inflate dictionary SetDictionary kept only the last 32767 bytes of a 32 KiB dictionary, because the window needs one free byte between its read and write positions. MS-ZIP sets the previous 32 KiB block as the dictionary, and a match at the start of a block can copy from 32768 bytes back, which then read a byte that was not in the window. A dictionary that fills the window now starts with the read and write positions at 0, so the first byte written replaces the oldest byte of the dictionary. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
468 lines
17 KiB
C#
468 lines
17 KiB
C#
// Inflate.cs
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// ------------------------------------------------------------------
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//
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// Copyright (c) 2009 Dino Chiesa and Microsoft Corporation.
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// All rights reserved.
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//
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// This code module is part of DotNetZip, a zipfile class library.
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//
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// ------------------------------------------------------------------
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//
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// This code is licensed under the Microsoft Public License.
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// See the file License.txt for the license details.
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// More info on: http://dotnetzip.codeplex.com
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//
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// ------------------------------------------------------------------
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//
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// last saved (in emacs):
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// Time-stamp: <2010-January-08 18:32:12>
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//
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// ------------------------------------------------------------------
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//
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// This module defines classes for decompression. This code is derived
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// from the jzlib implementation of zlib, but significantly modified.
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// The object model is not the same, and many of the behaviors are
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// different. Nonetheless, in keeping with the license for jzlib, I am
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// reproducing the copyright to that code here.
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//
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// ------------------------------------------------------------------
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//
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// Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in
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// the documentation and/or other materials provided with the distribution.
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//
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// 3. The names of the authors may not be used to endorse or promote products
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// derived from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
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// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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// FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
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// INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
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// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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// OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// -----------------------------------------------------------------------
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//
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// This program is based on zlib-1.1.3; credit to authors
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// Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu)
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// and contributors of zlib.
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//
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// -----------------------------------------------------------------------
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using System;
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#nullable disable
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namespace SabreTools.IO.Compression.Deflate
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{
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#pragma warning disable IDE0047
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#pragma warning disable IDE0049
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#pragma warning disable IDE2000
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#pragma warning disable IDE2003
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internal sealed class InflateManager
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{
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// preset dictionary flag in zlib header
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private const int PRESET_DICT = 0x20;
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private const int Z_DEFLATED = 8;
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private enum InflateManagerMode
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{
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METHOD = 0, // waiting for method byte
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FLAG = 1, // waiting for flag byte
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DICT4 = 2, // four dictionary check bytes to go
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DICT3 = 3, // three dictionary check bytes to go
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DICT2 = 4, // two dictionary check bytes to go
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DICT1 = 5, // one dictionary check byte to go
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DICT0 = 6, // waiting for inflateSetDictionary
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BLOCKS = 7, // decompressing blocks
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CHECK4 = 8, // four check bytes to go
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CHECK3 = 9, // three check bytes to go
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CHECK2 = 10, // two check bytes to go
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CHECK1 = 11, // one check byte to go
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DONE = 12, // finished check, done
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BAD = 13, // got an error--stay here
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}
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private InflateManagerMode mode; // current inflate mode
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internal ZlibCodec _codec; // pointer back to this zlib stream
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// mode dependent information
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internal int method; // if FLAGS, method byte
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// if CHECK, check values to compare
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internal uint computedCheck; // computed check value
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internal uint expectedCheck; // stream check value
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// if BAD, inflateSync's marker bytes count
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internal int marker;
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// mode independent information
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//internal int nowrap; // flag for no wrapper
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private bool _handleRfc1950HeaderBytes = true;
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internal bool HandleRfc1950HeaderBytes
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{
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get { return _handleRfc1950HeaderBytes; }
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set { _handleRfc1950HeaderBytes = value; }
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}
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internal int wbits; // log2(window size) (8..15, defaults to 15)
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internal InflateBlocks blocks; // current inflate_blocks state
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public InflateManager() { }
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public InflateManager(bool expectRfc1950HeaderBytes)
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{
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_handleRfc1950HeaderBytes = expectRfc1950HeaderBytes;
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}
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internal int Reset()
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{
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_codec.TotalBytesIn = _codec.TotalBytesOut = 0;
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_codec.Message = null;
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mode = HandleRfc1950HeaderBytes ? InflateManagerMode.METHOD : InflateManagerMode.BLOCKS;
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blocks.Reset();
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return ZlibConstants.Z_OK;
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}
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internal int End()
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{
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blocks?.Free();
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blocks = null;
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return ZlibConstants.Z_OK;
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}
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internal int Initialize(ZlibCodec codec, int w)
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{
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_codec = codec;
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_codec.Message = null;
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blocks = null;
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// handle undocumented nowrap option (no zlib header or check)
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//nowrap = 0;
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//if (w < 0)
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//{
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// w = - w;
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// nowrap = 1;
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//}
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// set window size
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if (w < 8 || w > 15)
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{
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End();
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throw new ZlibException("Bad window size.");
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//return ZlibConstants.Z_STREAM_ERROR;
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}
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wbits = w;
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blocks = new InflateBlocks(codec,
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HandleRfc1950HeaderBytes ? this : null,
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1 << w);
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// reset state
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Reset();
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return ZlibConstants.Z_OK;
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}
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internal int Inflate(FlushType flush)
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{
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int b;
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if (_codec.InputBuffer is null)
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throw new ZlibException("InputBuffer is null. ");
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// int f = (flush == FlushType.Finish)
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// ? ZlibConstants.Z_BUF_ERROR
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// : ZlibConstants.Z_OK;
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// workitem 8870
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int f = ZlibConstants.Z_OK;
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int r = ZlibConstants.Z_BUF_ERROR;
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while (true)
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{
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switch (mode)
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{
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case InflateManagerMode.METHOD:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--;
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_codec.TotalBytesIn++;
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if (((method = _codec.InputBuffer[_codec.NextIn++]) & 0xf) != Z_DEFLATED)
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{
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mode = InflateManagerMode.BAD;
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_codec.Message = String.Format("unknown compression method (0x{0:X2})", method);
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marker = 5; // can't try inflateSync
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break;
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}
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if ((method >> 4) + 8 > wbits)
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{
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mode = InflateManagerMode.BAD;
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_codec.Message = String.Format("invalid window size ({0})", (method >> 4) + 8);
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marker = 5; // can't try inflateSync
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break;
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}
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mode = InflateManagerMode.FLAG;
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break;
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case InflateManagerMode.FLAG:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--;
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_codec.TotalBytesIn++;
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b = (_codec.InputBuffer[_codec.NextIn++]) & 0xff;
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if ((((method << 8) + b) % 31) != 0)
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{
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mode = InflateManagerMode.BAD;
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_codec.Message = "incorrect header check";
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marker = 5; // can't try inflateSync
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break;
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}
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mode = ((b & PRESET_DICT) == 0)
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? InflateManagerMode.BLOCKS
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: InflateManagerMode.DICT4;
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break;
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case InflateManagerMode.DICT4:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--;
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_codec.TotalBytesIn++;
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expectedCheck = (uint)((_codec.InputBuffer[_codec.NextIn++] << 24) & 0xff000000);
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mode = InflateManagerMode.DICT3;
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break;
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case InflateManagerMode.DICT3:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--;
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_codec.TotalBytesIn++;
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expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 16) & 0x00ff0000);
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mode = InflateManagerMode.DICT2;
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break;
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case InflateManagerMode.DICT2:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--;
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_codec.TotalBytesIn++;
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expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 8) & 0x0000ff00);
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mode = InflateManagerMode.DICT1;
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break;
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case InflateManagerMode.DICT1:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
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expectedCheck += (uint)(_codec.InputBuffer[_codec.NextIn++] & 0x000000ff);
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_codec._Adler32 = expectedCheck;
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mode = InflateManagerMode.DICT0;
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return ZlibConstants.Z_NEED_DICT;
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case InflateManagerMode.DICT0:
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mode = InflateManagerMode.BAD;
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_codec.Message = "need dictionary";
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marker = 0; // can try inflateSync
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return ZlibConstants.Z_STREAM_ERROR;
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case InflateManagerMode.BLOCKS:
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r = blocks.Process(r);
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if (r == ZlibConstants.Z_DATA_ERROR)
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{
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mode = InflateManagerMode.BAD;
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marker = 0; // can try inflateSync
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break;
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}
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if (r == ZlibConstants.Z_OK) r = f;
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if (r != ZlibConstants.Z_STREAM_END)
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return r;
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r = f;
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computedCheck = blocks.Reset();
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if (!HandleRfc1950HeaderBytes)
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{
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mode = InflateManagerMode.DONE;
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return ZlibConstants.Z_STREAM_END;
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}
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mode = InflateManagerMode.CHECK4;
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break;
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case InflateManagerMode.CHECK4:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--;
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_codec.TotalBytesIn++;
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expectedCheck = (uint)((_codec.InputBuffer[_codec.NextIn++] << 24) & 0xff000000);
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mode = InflateManagerMode.CHECK3;
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break;
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case InflateManagerMode.CHECK3:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
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expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 16) & 0x00ff0000);
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mode = InflateManagerMode.CHECK2;
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break;
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case InflateManagerMode.CHECK2:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--;
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_codec.TotalBytesIn++;
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expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 8) & 0x0000ff00);
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mode = InflateManagerMode.CHECK1;
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break;
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case InflateManagerMode.CHECK1:
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if (_codec.AvailableBytesIn == 0) return r;
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r = f;
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_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
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expectedCheck += (uint)(_codec.InputBuffer[_codec.NextIn++] & 0x000000ff);
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if (computedCheck != expectedCheck)
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{
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mode = InflateManagerMode.BAD;
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_codec.Message = "incorrect data check";
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marker = 5; // can't try inflateSync
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break;
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}
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mode = InflateManagerMode.DONE;
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return ZlibConstants.Z_STREAM_END;
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case InflateManagerMode.DONE:
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return ZlibConstants.Z_STREAM_END;
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case InflateManagerMode.BAD:
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throw new ZlibException(String.Format("Bad state ({0})", _codec.Message));
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default:
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throw new ZlibException("Stream error.");
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}
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}
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}
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internal int SetDictionary(byte[] dictionary, bool check = true)
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{
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int index = 0;
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int length = dictionary.Length;
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if (check)
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{
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if (mode != InflateManagerMode.DICT0)
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throw new ZlibException("Stream error.");
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if (Adler.Adler32(1, dictionary, 0, dictionary.Length) != _codec._Adler32)
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{
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return ZlibConstants.Z_DATA_ERROR;
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}
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}
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_codec._Adler32 = Adler.Adler32(0, null, 0, 0);
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if (length > (1 << wbits))
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{
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length = 1 << wbits;
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index = dictionary.Length - length;
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}
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blocks.SetDictionary(dictionary, index, length);
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mode = InflateManagerMode.BLOCKS;
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return ZlibConstants.Z_OK;
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}
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private static readonly byte[] mark = [0, 0, 0xff, 0xff];
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internal int Sync()
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{
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int n; // number of bytes to look at
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int p; // pointer to bytes
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int m; // number of marker bytes found in a row
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long r, w; // temporaries to save total_in and total_out
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// set up
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if (mode != InflateManagerMode.BAD)
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{
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mode = InflateManagerMode.BAD;
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marker = 0;
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}
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if ((n = _codec.AvailableBytesIn) == 0)
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return ZlibConstants.Z_BUF_ERROR;
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p = _codec.NextIn;
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m = marker;
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// search
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while (n != 0 && m < 4)
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{
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if (_codec.InputBuffer[p] == mark[m])
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{
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m++;
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}
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else if (_codec.InputBuffer[p] != 0)
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{
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m = 0;
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}
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else
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{
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m = 4 - m;
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}
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p++; n--;
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}
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// restore
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_codec.TotalBytesIn += p - _codec.NextIn;
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_codec.NextIn = p;
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_codec.AvailableBytesIn = n;
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marker = m;
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// return no joy or set up to restart on a new block
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if (m != 4)
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{
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return ZlibConstants.Z_DATA_ERROR;
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}
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r = _codec.TotalBytesIn;
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w = _codec.TotalBytesOut;
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Reset();
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_codec.TotalBytesIn = r;
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_codec.TotalBytesOut = w;
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mode = InflateManagerMode.BLOCKS;
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return ZlibConstants.Z_OK;
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}
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// Returns true if inflate is currently at the end of a block generated
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// by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
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// implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
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// but removes the length bytes of the resulting empty stored block. When
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// decompressing, PPP checks that at the end of input packet, inflate is
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// waiting for these length bytes.
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internal int SyncPoint(ZlibCodec z)
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{
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return blocks.SyncPoint();
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}
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}
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}
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