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78 lines
1.9 KiB
C++
78 lines
1.9 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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*
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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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*
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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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*/
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#include "got/utils/compression.h"
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#include "common/algorithm.h"
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#include "common/endian.h"
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namespace Got {
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void decompressLzss(const byte *src, byte *dest, const size_t destSize) {
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byte *endP = dest + destSize;
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for (;;) {
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byte v = *src++;
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for (int bits = 8; bits > 0; --bits) {
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if (endP == dest)
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return;
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const bool bit = (v & 1) != 0;
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v >>= 1;
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if (bit) {
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*dest++ = *src++;
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} else {
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uint16 offset = READ_LE_UINT16(src);
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src += 2;
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const int count = (offset >> 12) + 2;
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offset &= 0xfff;
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Common::copy(dest - offset, dest - offset + count, dest);
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dest += count;
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}
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}
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}
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}
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void decompressRle(const byte *src, byte *dest, const size_t destSize) {
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byte *endP = dest + destSize;
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for (;;) {
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byte val = *src++;
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if ((val & 0x80) != 0) {
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const byte rep = *src++;
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val &= 0x7f;
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Common::fill(dest, dest + val, rep);
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dest += val;
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} else if (val > 0) {
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Common::copy(src, src + val, dest);
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src += val;
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dest += val;
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} else {
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break;
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}
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}
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assert(dest == endP);
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}
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} // namespace Got
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