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https://github.com/libretro/scummvm.git
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84 lines
2.5 KiB
C++
84 lines
2.5 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* $URL: https://scummvm-startrek.googlecode.com/svn/trunk/lzss.cpp $
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* $Id: lzss.cpp 18 2010-12-17 01:22:54Z clone2727 $
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*
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*/
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#include "common/textconsole.h"
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#include "common/memstream.h"
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#include "common/util.h"
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#include "startrek/lzss.h"
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namespace StarTrek {
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Common::SeekableReadStream *decodeLZSS(Common::SeekableReadStream *indata, uint32 uncompressedSize) {
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uint32 N = 0x1000; /* History buffer size */
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byte *histbuff = new byte[N](); /* History buffer */
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uint32 outstreampos = 0;
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uint32 bufpos = 0;
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byte *outLzssBufData = (byte *)malloc(uncompressedSize);
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for (;;) {
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byte flagbyte = indata->readByte();
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if (indata->eos())
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break;
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for (byte i = 0; i < 8; i++) {
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if ((flagbyte & (1 << i)) == 0) {
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uint32 offsetlen = indata->readUint16LE();
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if (indata->eos())
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break;
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uint32 length = (offsetlen & 0xF) + 3;
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uint32 offset = (bufpos - (offsetlen >> 4)) & (N - 1);
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for (uint32 j = 0; j < length; j++) {
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byte tempa = histbuff[(offset + j) & (N - 1)];
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outLzssBufData[outstreampos++] = tempa;
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histbuff[bufpos] = tempa;
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bufpos = (bufpos + 1) & (N - 1);
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}
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} else {
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byte tempa = indata->readByte();
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if (indata->eos())
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break;
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outLzssBufData[outstreampos++] = tempa;
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histbuff[bufpos] = tempa;
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bufpos = (bufpos + 1) & (N - 1);
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}
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}
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}
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delete[] histbuff;
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if (outstreampos != uncompressedSize)
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error("Size mismatch in LZSS decompression; expected %d bytes, got %d bytes", uncompressedSize, outstreampos);
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return new Common::MemoryReadStream(outLzssBufData, uncompressedSize, DisposeAfterUse::YES);
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}
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} // End of namespace StarTrek
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