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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) 1996-2014 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
{
lzo_bytep op;
const lzo_bytep ip;
lzo_uint t;
#if defined(COPY_DICT)
lzo_uint m_off;
const lzo_bytep dict_end;
#else
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;
NEED_IP(1);
if (*ip > 17)
{
t = *ip++ - 17;
if (t < 4)
goto match_next;
assert(t > 0); NEED_OP(t); NEED_IP(t+3);
do *op++ = *ip++; while (--t > 0);
goto first_literal_run;
}
for (;;)
{
NEED_IP(3);
t = *ip++;
if (t >= 16)
goto match;
/* a literal run */
if (t == 0)
{
while (*ip == 0)
{
t += 255;
ip++;
TEST_IV(t);
NEED_IP(1);
}
t += 15 + *ip++;
}
/* copy literals */
assert(t > 0); NEED_OP(t+3); NEED_IP(t+6);
#if (LZO_OPT_UNALIGNED64) && (LZO_OPT_UNALIGNED32)
t += 3;
if (t >= 8) do
{
UA_COPY8(op,ip);
op += 8; ip += 8; t -= 8;
} while (t >= 8);
if (t >= 4)
{
UA_COPY4(op,ip);
op += 4; ip += 4; t -= 4;
}
if (t > 0)
{
*op++ = *ip++;
if (t > 1) { *op++ = *ip++; if (t > 2) { *op++ = *ip++; } }
}
#elif (LZO_OPT_UNALIGNED32) || (LZO_ALIGNED_OK_4)
#if !(LZO_OPT_UNALIGNED32)
if (PTR_ALIGNED2_4(op,ip))
{
#endif
UA_COPY4(op,ip);
op += 4; ip += 4;
if (--t > 0)
{
if (t >= 4)
{
do {
UA_COPY4(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 !(LZO_OPT_UNALIGNED32)
}
else
#endif
#endif
#if !(LZO_OPT_UNALIGNED32)
{
*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 */
for (;;) {
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)
{
while (*ip == 0)
{
t += 255;
ip++;
TEST_OV(t);
NEED_IP(1);
}
t += 31 + *ip++;
NEED_IP(2);
}
#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 (LZO_OPT_UNALIGNED16) && (LZO_ABI_LITTLE_ENDIAN)
m_pos = op - 1;
m_pos -= UA_GET_LE16(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)
{
while (*ip == 0)
{
t += 255;
ip++;
TEST_OV(t);
NEED_IP(1);
}
t += 7 + *ip++;
NEED_IP(2);
}
#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 (LZO_OPT_UNALIGNED16) && (LZO_ABI_LITTLE_ENDIAN)
m_pos -= UA_GET_LE16(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 (LZO_OPT_UNALIGNED64) && (LZO_OPT_UNALIGNED32)
if (op - m_pos >= 8)
{
t += (3 - 1);
if (t >= 8) do
{
UA_COPY8(op,m_pos);
op += 8; m_pos += 8; t -= 8;
} while (t >= 8);
if (t >= 4)
{
UA_COPY4(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 (LZO_OPT_UNALIGNED32) || (LZO_ALIGNED_OK_4)
#if !(LZO_OPT_UNALIGNED32)
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_COPY4(op,m_pos);
op += 4; m_pos += 4; t -= 4 - (3 - 1);
do {
UA_COPY4(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+3);
#if 0
do *op++ = *ip++; while (--t > 0);
#else
*op++ = *ip++;
if (t > 1) { *op++ = *ip++; if (t > 2) { *op++ = *ip++; } }
#endif
t = *ip++;
}
}
eof_found:
*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
*/
|
