/* lzo1f_d.ch -- implementation of the LZO1F decompression algorithm
This file is part of the LZO real-time data compression library.
Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 1996 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.
************************************************************************/
LZO_PUBLIC(int)
DO_DECOMPRESS ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem )
{
register lzo_bytep op;
register const lzo_bytep ip;
register lzo_uint t;
register const lzo_bytep m_pos;
const lzo_bytep const ip_end = in + in_len;
#if defined(HAVE_ANY_OP)
lzo_bytep const op_end = out + *out_len;
#endif
LZO_UNUSED(wrkmem);
*out_len = 0;
op = out;
ip = in;
while (TEST_IP && TEST_OP)
{
t = *ip++;
if (t > 31)
goto match;
/* a literal run */
if (t == 0)
{
NEED_IP(1);
while (*ip == 0)
{
t += 255;
ip++;
NEED_IP(1);
}
t += 31 + *ip++;
}
/* copy literals */
assert(t > 0); NEED_OP(t); NEED_IP(t+1);
#if defined(LZO_UNALIGNED_OK_4)
if (t >= 4)
{
do {
* (lzo_uint32p) op = * (const lzo_uint32p) ip;
op += 4; ip += 4; t -= 4;
} while (t >= 4);
if (t > 0) do *op++ = *ip++; while (--t > 0);
}
else
#endif
do *op++ = *ip++; while (--t > 0);
t = *ip++;
while (TEST_IP && TEST_OP)
{
/* handle matches */
if (t < 32)
{
m_pos = op - 1 - 0x800;
m_pos -= (t >> 2) & 7;
m_pos -= *ip++ << 3;
TEST_LB(m_pos); NEED_OP(3);
*op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++;
}
else
{
match:
if (t < M3_MARKER)
{
m_pos = op - 1;
m_pos -= (t >> 2) & 7;
m_pos -= *ip++ << 3;
t >>= 5;
TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
goto copy_match;
}
else
{
t &= 31;
if (t == 0)
{
NEED_IP(1);
while (*ip == 0)
{
t += 255;
ip++;
NEED_IP(1);
}
t += 31 + *ip++;
}
NEED_IP(2);
m_pos = op;
#if defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
m_pos -= (* (const lzo_ushortp) ip) >> 2;
ip += 2;
#else
m_pos -= *ip++ >> 2;
m_pos -= *ip++ << 6;
#endif
if (m_pos == op)
goto eof_found;
}
/* copy match */
TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
#if defined(LZO_UNALIGNED_OK_4)
if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4)
{
* (lzo_uint32p) op = * (const lzo_uint32p) m_pos;
op += 4; m_pos += 4; t -= 4 - (3 - 1);
do {
* (lzo_uint32p) op = * (const lzo_uint32p) m_pos;
op += 4; m_pos += 4; t -= 4;
} while (t >= 4);
if (t > 0) do *op++ = *m_pos++; while (--t > 0);
}
else
#endif
{
copy_match:
*op++ = *m_pos++; *op++ = *m_pos++;
do *op++ = *m_pos++; while (--t > 0);
}
}
t = ip[-2] & 3;
if (t == 0)
break;
/* copy literals */
assert(t > 0); NEED_OP(t); NEED_IP(t+1);
do *op++ = *ip++; while (--t > 0);
t = *ip++;
}
}
#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);
*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
}
/*
vi:ts=4:et
*/