mirror of
https://github.com/libretro/scummvm.git
synced 2024-12-15 22:28:10 +00:00
134 lines
2.7 KiB
C++
134 lines
2.7 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 "bladerunner/decompress_lzo.h"
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namespace BladeRunner {
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static inline uint32 decode_count(const uint8 **pp) {
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uint32 v = 0;
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for (; !**pp; ++(*pp))
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v += 255;
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v += **pp;
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++(*pp);
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return v;
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}
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static inline void copy(uint8 **dst, const uint8 **src, int count) {
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assert(count > 0);
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uint8 *d = *dst;
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const uint8 *s = *src;
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*dst += count;
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*src += count;
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do { *d++ = *s++; } while (--count);
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}
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int decompress_lzo1x(const uint8 *in, size_t inLen, uint8 *out, size_t *outLen) {
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uint32 t;
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uint8 *op;
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const uint8 *ip, *m_pos;
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const uint8 * const ip_end = in + inLen;
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*outLen = 0;
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op = out;
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ip = in;
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if (*ip > 17) {
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t = *ip++ - 17;
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if (t < 4)
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goto match_next;
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copy(&op, &ip, t);
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goto first_literal_run;
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}
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for (;;) {
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t = *ip++;
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if (t >= 16)
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goto match;
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if (t == 0)
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t = 15 + decode_count(&ip);
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copy(&op, &ip, t + 3);
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first_literal_run:
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t = *ip++;
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if (t >= 16)
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goto match;
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m_pos = op - 0x0801 - (t >> 2) - (*ip++ << 2);
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copy(&op, &m_pos, 3);
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goto match_done;
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for (;;) {
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match:
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if (t >= 64) {
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m_pos = op - 1 - ((t >> 2) & 7) - (*ip++ << 3);
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t = (t >> 5) - 1;
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goto copy_match;
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} else if (t >= 32) {
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t &= 31;
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if (t == 0)
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t = 31 + decode_count(&ip);
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m_pos = op - 1 - (ip[0] >> 2) - (ip[1] << 6);
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ip += 2;
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} else if (t >= 16) {
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m_pos = op - ((t & 8) << 11);
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t &= 7;
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if (t == 0)
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t = 7 + decode_count(&ip);
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m_pos -= (ip[0] >> 2) + (ip[1] << 6);
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ip += 2;
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if (m_pos == op)
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goto eof_found;
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m_pos -= 0x4000;
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} else {
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m_pos = op - 1 - (t >> 2) - (*ip++ << 2);
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copy(&op, &m_pos, 2);
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goto match_done;
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}
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copy_match:
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copy(&op, &m_pos, t + 2);
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match_done:
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t = ip[-2] & 3;
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if (t == 0)
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break;
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match_next:
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assert(t > 0 && t <= 3);
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copy(&op, &ip, t);
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t = *ip++;
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}
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}
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eof_found:
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*outLen = op - out;
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return ip != ip_end;
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}
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} // End of namespace BladeRunner
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