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/* lzo2a_d.ch -- implementation of the LZO2A decompression algorithm
This file is part of the LZO real-time data compression library.
Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer
All Rights Reserved.
The LZO library 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.
The LZO library 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 the LZO library; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Markus F.X.J. Oberhumer
<markus@oberhumer.com>
http://www.oberhumer.com/opensource/lzo/
*/
#include "lzo1_d.ch"
/***********************************************************************
// decompress a block of data.
************************************************************************/
#define _NEEDBYTE NEED_IP(1)
#define _NEXTBYTE (*ip++)
LZO_PUBLIC(int)
DO_DECOMPRESS ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem )
{
lzo_bytep op;
const lzo_bytep ip;
const lzo_bytep m_pos;
lzo_uint t;
const lzo_bytep const ip_end = in + in_len;
#if defined(HAVE_ANY_OP)
lzo_bytep const op_end = out + *out_len;
#endif
lzo_uint32_t b = 0; /* bit buffer */
unsigned k = 0; /* bits in bit buffer */
LZO_UNUSED(wrkmem);
op = out;
ip = in;
while (TEST_IP_AND_TEST_OP)
{
NEEDBITS(1);
if (MASKBITS(1) == 0)
{
DUMPBITS(1);
/* a literal */
NEED_IP(1); NEED_OP(1);
*op++ = *ip++;
continue;
}
DUMPBITS(1);
NEEDBITS(1);
if (MASKBITS(1) == 0)
{
DUMPBITS(1);
/* a M1 match */
NEEDBITS(2);
t = M1_MIN_LEN + (lzo_uint) MASKBITS(2);
DUMPBITS(2);
NEED_IP(1); NEED_OP(t);
m_pos = op - 1 - *ip++;
assert(m_pos >= out); assert(m_pos < op);
TEST_LB(m_pos);
MEMCPY_DS(op,m_pos,t);
continue;
}
DUMPBITS(1);
NEED_IP(2);
t = *ip++;
m_pos = op;
m_pos -= (t & 31) | (((lzo_uint) *ip++) << 5);
t >>= 5;
if (t == 0)
{
#if (SWD_N >= 8192)
NEEDBITS(1);
t = MASKBITS(1);
DUMPBITS(1);
if (t == 0)
t = 10 - 1;
else
{
/* a M3 match */
m_pos -= 8192; /* t << 13 */
t = M3_MIN_LEN - 1;
}
#else
t = 10 - 1;
#endif
NEED_IP(1);
while (*ip == 0)
{
t += 255;
ip++;
TEST_OV(t);
NEED_IP(1);
}
t += *ip++;
}
else
{
#if defined(LZO_EOF_CODE)
if (m_pos == op)
goto eof_found;
#endif
t += 2;
}
assert(m_pos >= out); assert(m_pos < op);
TEST_LB(m_pos);
NEED_OP(t);
MEMCPY_DS(op,m_pos,t);
}
#if defined(LZO_EOF_CODE)
#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
/* no EOF code was found */
*out_len = pd(op, out);
return LZO_E_EOF_NOT_FOUND;
#endif
eof_found:
assert(t == 1);
#endif
*out_len = pd(op, out);
return (ip == ip_end ? LZO_E_OK :
(ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
#if defined(HAVE_NEED_IP)
input_overrun:
*out_len = pd(op, out);
return LZO_E_INPUT_OVERRUN;
#endif
#if defined(HAVE_NEED_OP)
output_overrun:
*out_len = pd(op, out);
return LZO_E_OUTPUT_OVERRUN;
#endif
#if defined(LZO_TEST_OVERRUN_LOOKBEHIND)
lookbehind_overrun:
*out_len = pd(op, out);
return LZO_E_LOOKBEHIND_OVERRUN;
#endif
}
/* vim:set ts=4 sw=4 et: */
|
