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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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 "bladerunner/decompress_lzo.h"
namespace BladeRunner {
static inline uint32 decode_count(const uint8 **pp) {
uint32 v = 0;
for (; !**pp; (*pp)++)
v += 255;
v += **pp;
(*pp)++;
return v;
}
static inline void copy(uint8 **dst, const uint8 **src, int count) {
assert(count > 0);
uint8 *d = *dst;
const uint8 *s = *src;
*dst += count;
*src += count;
do { *d++ = *s++; } while (--count);
}
int decompress_lzo1x(const uint8 *in, size_t inLen, uint8 *out, size_t *outLen) {
uint32 t;
uint8 *op;
const uint8 *ip, *m_pos;
const uint8 * const ip_end = in + inLen;
*outLen = 0;
op = out;
ip = in;
if (*ip > 17) {
t = *ip++ - 17;
if (t < 4)
goto match_next;
copy(&op, &ip, t);
goto first_literal_run;
}
for (;;) {
t = *ip++;
if (t >= 16)
goto match;
if (t == 0)
t = 15 + decode_count(&ip);
copy(&op, &ip, t + 3);
first_literal_run:
t = *ip++;
if (t >= 16)
goto match;
m_pos = op - 0x0801 - (t >> 2) - (*ip++ << 2);
copy(&op, &m_pos, 3);
goto match_done;
for (;;) {
match:
if (t >= 64) {
m_pos = op - 1 - ((t >> 2) & 7) - (*ip++ << 3);
t = (t >> 5) - 1;
goto copy_match;
} else if (t >= 32) {
t &= 31;
if (t == 0)
t = 31 + decode_count(&ip);
m_pos = op - 1 - (ip[0] >> 2) - (ip[1] << 6);
ip += 2;
} else if (t >= 16) {
m_pos = op - ((t & 8) << 11);
t &= 7;
if (t == 0)
t = 7 + decode_count(&ip);
m_pos -= (ip[0] >> 2) + (ip[1] << 6);
ip += 2;
if (m_pos == op)
goto eof_found;
m_pos -= 0x4000;
} else {
m_pos = op - 1 - (t >> 2) - (*ip++ << 2);
copy(&op, &m_pos, 2);
goto match_done;
}
copy_match:
copy(&op, &m_pos, t + 2);
match_done:
t = ip[-2] & 3;
if (t == 0)
break;
match_next:
assert(t > 0 && t <= 3);
copy(&op, &ip, t);
t = *ip++;
}
}
eof_found:
*outLen = op - out;
return ip != ip_end;
}
} // End of namespace BladeRunner
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