/* lzo2a_9x.c -- implementation of the LZO2A-999 compression 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 "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_t 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
*/