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/*
* Copyright (C) 2004-2012 Geometer Plus <contact@geometerplus.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include <cstring>
#include <ZLInputStream.h>
#include "DocDecompressor.h"
static unsigned char TOKEN_CODE[256] = {
0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
};
std::size_t DocDecompressor::decompress(ZLInputStream &stream, char *targetBuffer, std::size_t compressedSize, std::size_t maxUncompressedSize) {
const unsigned char *sourceBuffer = new unsigned char[compressedSize];
const unsigned char *sourceBufferEnd = sourceBuffer + compressedSize;
const unsigned char *sourcePtr = sourceBuffer;
unsigned char *targetBufferEnd = (unsigned char*)targetBuffer + maxUncompressedSize;
unsigned char *targetPtr = (unsigned char*)targetBuffer;
if (stream.read((char*)sourceBuffer, compressedSize) == compressedSize) {
unsigned char token;
unsigned short copyLength, N, shift;
unsigned char *shifted;
while ((sourcePtr < sourceBufferEnd) && (targetPtr < targetBufferEnd)) {
token = *(sourcePtr++);
switch (TOKEN_CODE[token]) {
case 0:
*(targetPtr++) = token;
break;
case 1:
if ((sourcePtr + token > sourceBufferEnd) || (targetPtr + token > targetBufferEnd)) {
goto endOfLoop;
}
std::memcpy(targetPtr, sourcePtr, token);
sourcePtr += token;
targetPtr += token;
break;
case 2:
if (targetPtr + 2 > targetBufferEnd) {
goto endOfLoop;
}
*(targetPtr++) = ' ';
*(targetPtr++) = token ^ 0x80;
break;
case 3:
if (sourcePtr + 1 > sourceBufferEnd) {
goto endOfLoop;
}
N = 256 * token + *(sourcePtr++);
copyLength = (N & 7) + 3;
if (targetPtr + copyLength > targetBufferEnd) {
goto endOfLoop;
}
shift = (N & 0x3fff) / 8;
shifted = targetPtr - shift;
if ((char*)shifted >= targetBuffer) {
for (short i = 0; i < copyLength; i++) {
*(targetPtr++) = *(shifted++);
}
}
break;
}
}
}
endOfLoop:
delete[] sourceBuffer;
return targetPtr - (unsigned char*)targetBuffer;
}
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