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/* lzo2a_9x.c -- implementation of the LZO2A-999 compression 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 "config2a.h"
/***********************************************************************
//
************************************************************************/
#define SWD_THRESHOLD 1 /* lower limit for match length */
#define SWD_F 2048 /* upper limit for match length */
#define LZO2A 1
#define LZO_COMPRESS_T lzo2a_999_t
#define lzo_swd_t lzo2a_999_swd_t
#include "lzo_mchw.ch"
#if (LZO_CC_BORLANDC && LZO_MM_FLAT)
# if ((__BORLANDC__) >= 0x0450 && (__BORLANDC__) < 0x0460)
/* avoid internal compiler error */
# pragma option -Od
# endif
#endif
/***********************************************************************
//
************************************************************************/
#define putbyte(x) *op++ = LZO_BYTE(x)
#define putbits(j,x) \
if (k == 0) bitp = op++; \
SETBITS(j,x); \
if (k >= 8) { *bitp = LZO_BYTE(MASKBITS(8)); DUMPBITS(8); \
if (k > 0) bitp = op++; }
#define putbit(x) putbits(1,x)
/***********************************************************************
// this is a public function, but there is no prototype in a header file
************************************************************************/
LZO_EXTERN(int)
lzo2a_999_compress_callback ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem,
lzo_callback_p cb,
lzo_uint max_chain );
LZO_PUBLIC(int)
lzo2a_999_compress_callback ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem,
lzo_callback_p cb,
lzo_uint max_chain )
{
lzo_bytep op;
lzo_bytep bitp = 0;
lzo_uint m_len, m_off;
LZO_COMPRESS_T cc;
LZO_COMPRESS_T * const c = &cc;
lzo_swd_p const swd = (lzo_swd_p) wrkmem;
int r;
lzo_uint32 b = 0; /* bit buffer */
unsigned k = 0; /* bits in bit buffer */
/* sanity check */
LZO_COMPILE_TIME_ASSERT(LZO2A_999_MEM_COMPRESS >= SIZEOF_LZO_SWD_T)
c->init = 0;
c->ip = c->in = in;
c->in_end = in + in_len;
c->cb = cb;
c->m1 = c->m2 = c->m3 = c->m4 = 0;
op = out;
r = init_match(c,swd,NULL,0,0);
if (r != 0)
return r;
if (max_chain > 0)
swd->max_chain = max_chain;
r = find_match(c,swd,0,0);
if (r != 0)
return r;
while (c->look > 0)
{
lzo_uint lazy_match_min_gain = 0;
#if (SWD_N >= 8192)
lzo_uint extra1 = 0;
#endif
lzo_uint extra2 = 0;
lzo_uint ahead = 0;
m_len = c->m_len;
m_off = c->m_off;
#if (SWD_N >= 8192)
if (m_off >= 8192)
{
if (m_len < M3_MIN_LEN)
m_len = 0;
else
lazy_match_min_gain = 1;
}
else
#endif
if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
{
lazy_match_min_gain = 2;
#if (SWD_N >= 8192)
extra1 = 3;
#endif
extra2 = 2;
}
else if (m_len >= 10)
lazy_match_min_gain = 1;
else if (m_len >= 3)
{
lazy_match_min_gain = 1;
#if (SWD_N >= 8192)
extra1 = 1;
#endif
}
else
m_len = 0;
/* try a lazy match */
if (lazy_match_min_gain > 0 && c->look > m_len)
{
unsigned char lit = LZO_BYTE(swd->b_char);
r = find_match(c,swd,1,0);
assert(r == 0); LZO_UNUSED(r);
assert(c->look > 0);
#if (SWD_N >= 8192)
if (m_off < 8192 && c->m_off >= 8192)
lazy_match_min_gain += extra1;
else
#endif
if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
{
if (!(c->m_len >= M1_MIN_LEN &&
c->m_len <= M1_MAX_LEN && c->m_off <= 256))
lazy_match_min_gain += extra2;
}
if (c->m_len >= M1_MIN_LEN &&
c->m_len <= M1_MAX_LEN && c->m_off <= 256)
{
lazy_match_min_gain -= 1;
}
if ((lzo_int) lazy_match_min_gain < 1)
lazy_match_min_gain = 1;
if (c->m_len >= m_len + lazy_match_min_gain)
{
c->lazy++;
#if !defined(NDEBUG)
m_len = c->m_len;
m_off = c->m_off;
assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
m_len) == 0);
assert(m_len >= 3 || (m_len >= 2 && m_off <= 256));
#endif
/* code literal */
putbit(0);
putbyte(lit);
c->lit_bytes++;
continue;
}
else
ahead = 1;
assert(m_len > 0);
}
if (m_len == 0)
{
/* a literal */
putbit(0);
putbyte(swd->b_char);
c->lit_bytes++;
r = find_match(c,swd,1,0);
assert(r == 0); LZO_UNUSED(r);
}
else
{
assert(m_len >= M1_MIN_LEN);
assert(m_off > 0);
assert(m_off <= SWD_N);
/* 2 - code match */
if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
{
putbit(1);
putbit(0);
putbits(2,m_len - M1_MIN_LEN);
putbyte(m_off - 1);
c->m1++;
}
#if (SWD_N >= 8192)
else if (m_off >= 8192)
{
unsigned len = m_len;
assert(m_len >= M3_MIN_LEN);
putbit(1);
putbit(1);
putbyte(m_off & 31);
putbyte(m_off >> 5);
putbit(1);
len -= M3_MIN_LEN - 1;
while (len > 255)
{
len -= 255;
putbyte(0);
}
putbyte(len);
c->m4++;
}
#endif
else
{
assert(m_len >= 3);
putbit(1);
putbit(1);
if (m_len <= 9)
{
putbyte(((m_len - 2) << 5) | (m_off & 31));
putbyte(m_off >> 5);
c->m2++;
}
else
{
lzo_uint len = m_len;
putbyte(m_off & 31);
putbyte(m_off >> 5);
#if (SWD_N >= 8192)
putbit(0);
#endif
len -= 10 - 1;
while (len > 255)
{
len -= 255;
putbyte(0);
}
putbyte(len);
c->m3++;
}
}
r = find_match(c,swd,m_len,1+ahead);
assert(r == 0); LZO_UNUSED(r);
}
c->codesize = pd(op, out);
}
#if defined(LZO_EOF_CODE)
/* code EOF code */
putbit(1);
putbit(1);
putbyte(1 << 5);
putbyte(0);
#endif
/* flush remaining bits */
assert(k < CHAR_BIT);
if (k > 0)
{
assert(b == MASKBITS(k));
assert(op - bitp > 1);
*bitp = LZO_BYTE(MASKBITS(k));
DUMPBITS(k);
assert(b == 0);
assert(k == 0);
}
assert(c->textsize == in_len);
c->codesize = pd(op, out);
*out_len = pd(op, out);
if (c->cb && c->cb->nprogress)
(*c->cb->nprogress)(c->cb, c->textsize, c->codesize, 0);
#if 0
printf("%ld -> %ld: %ld %ld %ld %ld %ld %ld\n",
(long) c->textsize, (long) c->codesize,
c->lit_bytes, c->m1, c->m2, c->m3, c->m4, c->lazy);
#endif
return LZO_E_OK;
}
/***********************************************************************
//
************************************************************************/
LZO_PUBLIC(int)
lzo2a_999_compress ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem )
{
return lzo2a_999_compress_callback(in,in_len,out,out_len,wrkmem,
(lzo_callback_p) 0, 0);
}
/*
vi:ts=4:et
*/
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