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athena/extern/lzo/src/lzo1x_oo.ch

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/* lzo1x_oo.ch -- LZO1X compressed data optimizer
This file is part of the LZO real-time data compression library.
Copyright (C) 1996-2015 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/
*/
#define TEST_IP (ip < ip_end)
#define TEST_OP (op <= op_end)
#define TEST_IP_AND_TEST_OP (TEST_IP && TEST_OP)
#define NO_LIT LZO_UINT_MAX
/***********************************************************************
//
************************************************************************/
static void copy2(lzo_bytep ip, const lzo_bytep m_pos, lzo_uint off)
{
assert(off > 0);
ip[0] = m_pos[0];
if (off == 1)
ip[1] = m_pos[0];
else
ip[1] = m_pos[1];
}
static void copy3(lzo_bytep ip, const lzo_bytep m_pos, lzo_uint off)
{
assert(off > 0);
ip[0] = m_pos[0];
if (off == 1)
{
ip[2] = ip[1] = m_pos[0];
}
else if (off == 2)
{
ip[1] = m_pos[1];
ip[2] = m_pos[0];
}
else
{
ip[1] = m_pos[1];
ip[2] = m_pos[2];
}
}
/***********************************************************************
// optimize a block of data.
************************************************************************/
LZO_PUBLIC(int)
DO_OPTIMIZE(lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem)
{
lzo_bytep op;
lzo_bytep ip;
lzo_uint t;
lzo_bytep m_pos;
lzo_bytep const ip_end = in + in_len;
lzo_bytep const op_end = out + *out_len;
lzo_bytep litp = NULL;
lzo_uint lit = 0;
lzo_uint next_lit = NO_LIT;
lzo_uint nl;
unsigned long o_m1_a = 0, o_m1_b = 0, o_m2 = 0, o_m3_a = 0, o_m3_b = 0;
LZO_UNUSED(wrkmem);
*out_len = 0;
op = out;
ip = in;
assert(in_len >= 3);
if (*ip > 17)
{
t = *ip++ - 17;
if (t < 4)
goto match_next;
goto first_literal_run;
}
assert(*ip < 16 || (*ip == 17 && in_len == 3));
while (TEST_IP_AND_TEST_OP)
{
t = *ip++;
if (t >= 16)
goto match;
/* a literal run */
litp = ip - 1;
if (t == 0)
{
t = 15;
while (*ip == 0)
t += 255, ip++;
t += *ip++;
}
lit = t + 3;
/* copy literals */
copy_literal_run:
*op++ = *ip++;
*op++ = *ip++;
*op++ = *ip++;
first_literal_run:
do* op++ = *ip++;
while (--t > 0);
t = *ip++;
if (t >= 16)
goto match;
#if defined(LZO1X)
m_pos = op - 1 - 0x800;
#elif defined(LZO1Y)
m_pos = op - 1 - 0x400;
#endif
m_pos -= t >> 2;
m_pos -= *ip++ << 2;
*op++ = *m_pos++;
*op++ = *m_pos++;
*op++ = *m_pos++;
lit = 0;
goto match_done;
/* handle matches */
do
{
if (t < 16) /* a M1 match */
{
m_pos = op - 1;
m_pos -= t >> 2;
m_pos -= *ip++ << 2;
if (litp == NULL)
goto copy_m1;
/* assert that there was a match just before */
assert(lit >= 1 && lit <= 3);
assert(litp == ip - 2 - lit - 2);
assert((lzo_uint)(*litp & 3) == lit);
nl = ip[-2] & 3;
/* test if a match follows */
if (nl == 0 && lit == 1 && ip[0] >= 16)
{
next_lit = nl;
/* adjust length of previous short run */
lit += 2;
*litp = LZO_BYTE((*litp & ~3) | lit);
/* copy over the 2 literals that replace the match */
copy2(ip - 2, m_pos, pd(op, m_pos));
o_m1_a++;
}
/* test if a literal run follows */
else if (nl == 0 && ip[0] < 16 && ip[0] != 0 &&
(lit + 2 + ip[0] < 16))
{
t = *ip++;
/* remove short run */
*litp &= ~3;
/* copy over the 2 literals that replace the match */
copy2(ip - 3 + 1, m_pos, pd(op, m_pos));
/* move literals 1 byte ahead */
litp += 2;
if (lit > 0)
lzo_memmove(litp + 1, litp, lit);
/* insert new length of long literal run */
lit += 2 + t + 3;
assert(lit <= 18);
*litp = LZO_BYTE(lit - 3);
o_m1_b++;
*op++ = *m_pos++;
*op++ = *m_pos++;
goto copy_literal_run;
}
copy_m1:
*op++ = *m_pos++;
*op++ = *m_pos++;
}
else
{
match:
if (t >= 64) /* a M2 match */
{
m_pos = op - 1;
#if defined(LZO1X)
m_pos -= (t >> 2) & 7;
m_pos -= *ip++ << 3;
t = (t >> 5) - 1;
#elif defined(LZO1Y)
m_pos -= (t >> 2) & 3;
m_pos -= *ip++ << 2;
t = (t >> 4) - 3;
#endif
if (litp == NULL)
goto copy_m;
nl = ip[-2] & 3;
/* test if in beetween two long literal runs */
if (t == 1 && lit > 3 && nl == 0 &&
ip[0] < 16 && ip[0] != 0 && (lit + 3 + ip[0] < 16))
{
assert(*litp == lit - 3);
t = *ip++;
/* copy over the 3 literals that replace the match */
copy3(ip - 1 - 2, m_pos, pd(op, m_pos));
/* set new length of previous literal run */
lit += 3 + t + 3;
assert(lit <= 18);
*litp = LZO_BYTE(lit - 3);
o_m2++;
*op++ = *m_pos++;
*op++ = *m_pos++;
*op++ = *m_pos++;
goto copy_literal_run;
}
}
else
{
if (t >= 32) /* a M3 match */
{
t &= 31;
if (t == 0)
{
t = 31;
while (*ip == 0)
t += 255, ip++;
t += *ip++;
}
m_pos = op - 1;
m_pos -= *ip++ >> 2;
m_pos -= *ip++ << 6;
}
else /* a M4 match */
{
m_pos = op;
m_pos -= (t & 8) << 11;
t &= 7;
if (t == 0)
{
t = 7;
while (*ip == 0)
t += 255, ip++;
t += *ip++;
}
m_pos -= *ip++ >> 2;
m_pos -= *ip++ << 6;
if (m_pos == op)
goto eof_found;
m_pos -= 0x4000;
}
if (litp == NULL)
goto copy_m;
nl = ip[-2] & 3;
/* test if in beetween two matches */
if (t == 1 && lit == 0 && nl == 0 && ip[0] >= 16)
{
assert(litp == ip - 3 - lit - 2);
assert((lzo_uint)(*litp & 3) == lit);
next_lit = nl;
/* make a previous short run */
lit += 3;
*litp = LZO_BYTE((*litp & ~3) | lit);
/* copy over the 3 literals that replace the match */
copy3(ip - 3, m_pos, pd(op, m_pos));
o_m3_a++;
}
/* test if a literal run follows */
else if (t == 1 && lit <= 3 && nl == 0 &&
ip[0] < 16 && ip[0] != 0 && (lit + 3 + ip[0] < 16))
{
assert(litp == ip - 3 - lit - 2);
assert((lzo_uint)(*litp & 3) == lit);
t = *ip++;
/* remove short run */
*litp &= ~3;
/* copy over the 3 literals that replace the match */
copy3(ip - 4 + 1, m_pos, pd(op, m_pos));
/* move literals 1 byte ahead */
litp += 2;
if (lit > 0)
lzo_memmove(litp + 1, litp, lit);
/* insert new length of long literal run */
lit += 3 + t + 3;
assert(lit <= 18);
*litp = LZO_BYTE(lit - 3);
o_m3_b++;
*op++ = *m_pos++;
*op++ = *m_pos++;
*op++ = *m_pos++;
goto copy_literal_run;
}
}
copy_m:
*op++ = *m_pos++;
*op++ = *m_pos++;
do* op++ = *m_pos++;
while (--t > 0);
}
match_done:
if (next_lit == NO_LIT)
{
t = ip[-2] & 3;
lit = t;
litp = ip - 2;
}
else
t = next_lit;
assert(t <= 3);
next_lit = NO_LIT;
if (t == 0)
break;
/* copy literals */
match_next:
do* op++ = *ip++;
while (--t > 0);
t = *ip++;
}
while (TEST_IP_AND_TEST_OP);
}
/* no EOF code was found */
*out_len = pd(op, out);
return LZO_E_EOF_NOT_FOUND;
eof_found:
assert(t == 1);
#if 0
printf("optimize: %5lu %5lu %5lu %5lu %5lu\n",
o_m1_a, o_m1_b, o_m2, o_m3_a, o_m3_b);
#endif
LZO_UNUSED(o_m1_a);
LZO_UNUSED(o_m1_b);
LZO_UNUSED(o_m2);
LZO_UNUSED(o_m3_a);
LZO_UNUSED(o_m3_b);
*out_len = pd(op, out);
return (ip == ip_end ? LZO_E_OK :
(ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
}
/* vim:set ts=4 sw=4 et: */
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