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|
/* lzo1x_d.ch -- implementation of the LZO1X decompression algorithm
This file is part of the LZO real-time data compression library.
Copyright (C) 2011 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2010 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 2009 Markus Franz Xaver Johannes Oberhumer
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.
************************************************************************/
#if defined(DO_DECOMPRESS)
LZO_PUBLIC(int)
DO_DECOMPRESS ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem )
#endif
{
register lzo_bytep op;
register const lzo_bytep ip;
register lzo_uint t;
#if defined(COPY_DICT)
lzo_uint m_off;
const lzo_bytep dict_end;
#else
register const lzo_bytep m_pos;
#endif
const lzo_bytep const ip_end = in + in_len;
#if defined(HAVE_ANY_OP)
lzo_bytep const op_end = out + *out_len;
#endif
#if defined(LZO1Z)
lzo_uint last_m_off = 0;
#endif
LZO_UNUSED(wrkmem);
#if defined(COPY_DICT)
if (dict)
{
if (dict_len > M4_MAX_OFFSET)
{
dict += dict_len - M4_MAX_OFFSET;
dict_len = M4_MAX_OFFSET;
}
dict_end = dict + dict_len;
}
else
{
dict_len = 0;
dict_end = NULL;
}
#endif /* COPY_DICT */
*out_len = 0;
op = out;
ip = in;
if (*ip > 17)
{
t = *ip++ - 17;
if (t < 4)
goto match_next;
assert(t > 0); NEED_OP(t); NEED_IP(t+1);
do *op++ = *ip++; while (--t > 0);
goto first_literal_run;
}
while (TEST_IP && TEST_OP)
{
t = *ip++;
if (t >= 16)
goto match;
/* a literal run */
if (t == 0)
{
NEED_IP(1);
while (*ip == 0)
{
t += 255;
ip++;
NEED_IP(1);
}
t += 15 + *ip++;
}
/* copy literals */
assert(t > 0); NEED_OP(t+3); NEED_IP(t+4);
#if defined(LZO_UNALIGNED_OK_8) && defined(LZO_UNALIGNED_OK_4)
t += 3;
if (t >= 8) do
{
UA_COPY64(op,ip);
op += 8; ip += 8; t -= 8;
} while (t >= 8);
if (t >= 4)
{
UA_COPY32(op,ip);
op += 4; ip += 4; t -= 4;
}
if (t > 0)
{
*op++ = *ip++;
if (t > 1) { *op++ = *ip++; if (t > 2) { *op++ = *ip++; } }
}
#elif defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
#if !defined(LZO_UNALIGNED_OK_4)
if (PTR_ALIGNED2_4(op,ip))
{
#endif
UA_COPY32(op,ip);
op += 4; ip += 4;
if (--t > 0)
{
if (t >= 4)
{
do {
UA_COPY32(op,ip);
op += 4; ip += 4; t -= 4;
} while (t >= 4);
if (t > 0) do *op++ = *ip++; while (--t > 0);
}
else
do *op++ = *ip++; while (--t > 0);
}
#if !defined(LZO_UNALIGNED_OK_4)
}
else
#endif
#endif
#if !defined(LZO_UNALIGNED_OK_4) && !defined(LZO_UNALIGNED_OK_8)
{
*op++ = *ip++; *op++ = *ip++; *op++ = *ip++;
do *op++ = *ip++; while (--t > 0);
}
#endif
first_literal_run:
t = *ip++;
if (t >= 16)
goto match;
#if defined(COPY_DICT)
#if defined(LZO1Z)
m_off = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
last_m_off = m_off;
#else
m_off = (1 + M2_MAX_OFFSET) + (t >> 2) + (*ip++ << 2);
#endif
NEED_OP(3);
t = 3; COPY_DICT(t,m_off)
#else /* !COPY_DICT */
#if defined(LZO1Z)
t = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
m_pos = op - t;
last_m_off = t;
#else
m_pos = op - (1 + M2_MAX_OFFSET);
m_pos -= t >> 2;
m_pos -= *ip++ << 2;
#endif
TEST_LB(m_pos); NEED_OP(3);
*op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos;
#endif /* COPY_DICT */
goto match_done;
/* handle matches */
do {
match:
if (t >= 64) /* a M2 match */
{
#if defined(COPY_DICT)
#if defined(LZO1X)
m_off = 1 + ((t >> 2) & 7) + (*ip++ << 3);
t = (t >> 5) - 1;
#elif defined(LZO1Y)
m_off = 1 + ((t >> 2) & 3) + (*ip++ << 2);
t = (t >> 4) - 3;
#elif defined(LZO1Z)
m_off = t & 0x1f;
if (m_off >= 0x1c)
m_off = last_m_off;
else
{
m_off = 1 + (m_off << 6) + (*ip++ >> 2);
last_m_off = m_off;
}
t = (t >> 5) - 1;
#endif
#else /* !COPY_DICT */
#if defined(LZO1X)
m_pos = op - 1;
m_pos -= (t >> 2) & 7;
m_pos -= *ip++ << 3;
t = (t >> 5) - 1;
#elif defined(LZO1Y)
m_pos = op - 1;
m_pos -= (t >> 2) & 3;
m_pos -= *ip++ << 2;
t = (t >> 4) - 3;
#elif defined(LZO1Z)
{
lzo_uint off = t & 0x1f;
m_pos = op;
if (off >= 0x1c)
{
assert(last_m_off > 0);
m_pos -= last_m_off;
}
else
{
off = 1 + (off << 6) + (*ip++ >> 2);
m_pos -= off;
last_m_off = off;
}
}
t = (t >> 5) - 1;
#endif
TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
goto copy_match;
#endif /* COPY_DICT */
}
else if (t >= 32) /* a M3 match */
{
t &= 31;
if (t == 0)
{
NEED_IP(1);
while (*ip == 0)
{
t += 255;
ip++;
NEED_IP(1);
}
t += 31 + *ip++;
}
#if defined(COPY_DICT)
#if defined(LZO1Z)
m_off = 1 + (ip[0] << 6) + (ip[1] >> 2);
last_m_off = m_off;
#else
m_off = 1 + (ip[0] >> 2) + (ip[1] << 6);
#endif
#else /* !COPY_DICT */
#if defined(LZO1Z)
{
lzo_uint off = 1 + (ip[0] << 6) + (ip[1] >> 2);
m_pos = op - off;
last_m_off = off;
}
#elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
m_pos = op - 1;
m_pos -= UA_GET16(ip) >> 2;
#else
m_pos = op - 1;
m_pos -= (ip[0] >> 2) + (ip[1] << 6);
#endif
#endif /* COPY_DICT */
ip += 2;
}
else if (t >= 16) /* a M4 match */
{
#if defined(COPY_DICT)
m_off = (t & 8) << 11;
#else /* !COPY_DICT */
m_pos = op;
m_pos -= (t & 8) << 11;
#endif /* COPY_DICT */
t &= 7;
if (t == 0)
{
NEED_IP(1);
while (*ip == 0)
{
t += 255;
ip++;
NEED_IP(1);
}
t += 7 + *ip++;
}
#if defined(COPY_DICT)
#if defined(LZO1Z)
m_off += (ip[0] << 6) + (ip[1] >> 2);
#else
m_off += (ip[0] >> 2) + (ip[1] << 6);
#endif
ip += 2;
if (m_off == 0)
goto eof_found;
m_off += 0x4000;
#if defined(LZO1Z)
last_m_off = m_off;
#endif
#else /* !COPY_DICT */
#if defined(LZO1Z)
m_pos -= (ip[0] << 6) + (ip[1] >> 2);
#elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
m_pos -= UA_GET16(ip) >> 2;
#else
m_pos -= (ip[0] >> 2) + (ip[1] << 6);
#endif
ip += 2;
if (m_pos == op)
goto eof_found;
m_pos -= 0x4000;
#if defined(LZO1Z)
last_m_off = pd((const lzo_bytep)op, m_pos);
#endif
#endif /* COPY_DICT */
}
else /* a M1 match */
{
#if defined(COPY_DICT)
#if defined(LZO1Z)
m_off = 1 + (t << 6) + (*ip++ >> 2);
last_m_off = m_off;
#else
m_off = 1 + (t >> 2) + (*ip++ << 2);
#endif
NEED_OP(2);
t = 2; COPY_DICT(t,m_off)
#else /* !COPY_DICT */
#if defined(LZO1Z)
t = 1 + (t << 6) + (*ip++ >> 2);
m_pos = op - t;
last_m_off = t;
#else
m_pos = op - 1;
m_pos -= t >> 2;
m_pos -= *ip++ << 2;
#endif
TEST_LB(m_pos); NEED_OP(2);
*op++ = *m_pos++; *op++ = *m_pos;
#endif /* COPY_DICT */
goto match_done;
}
/* copy match */
#if defined(COPY_DICT)
NEED_OP(t+3-1);
t += 3-1; COPY_DICT(t,m_off)
#else /* !COPY_DICT */
TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
#if defined(LZO_UNALIGNED_OK_8) && defined(LZO_UNALIGNED_OK_4)
if (op - m_pos >= 8)
{
t += (3 - 1);
if (t >= 8) do
{
UA_COPY64(op,m_pos);
op += 8; m_pos += 8; t -= 8;
} while (t >= 8);
if (t >= 4)
{
UA_COPY32(op,m_pos);
op += 4; m_pos += 4; t -= 4;
}
if (t > 0)
{
*op++ = m_pos[0];
if (t > 1) { *op++ = m_pos[1]; if (t > 2) { *op++ = m_pos[2]; } }
}
}
else
#elif defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
#if !defined(LZO_UNALIGNED_OK_4)
if (t >= 2 * 4 - (3 - 1) && PTR_ALIGNED2_4(op,m_pos))
{
assert((op - m_pos) >= 4); /* both pointers are aligned */
#else
if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4)
{
#endif
UA_COPY32(op,m_pos);
op += 4; m_pos += 4; t -= 4 - (3 - 1);
do {
UA_COPY32(op,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);
}
#endif /* COPY_DICT */
match_done:
#if defined(LZO1Z)
t = ip[-1] & 3;
#else
t = ip[-2] & 3;
#endif
if (t == 0)
break;
/* copy literals */
match_next:
assert(t > 0); assert(t < 4); NEED_OP(t); NEED_IP(t+1);
#if 0
do *op++ = *ip++; while (--t > 0);
#else
*op++ = *ip++;
if (t > 1) { *op++ = *ip++; if (t > 2) { *op++ = *ip++; } }
#endif
t = *ip++;
} while (TEST_IP && TEST_OP);
}
#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
*/
|
