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/* lzo1b_9x.c -- implementation of the LZO1B-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 "config1b.h"
/***********************************************************************
//
************************************************************************/
#define SWD_N 0xffffL /* size of ring buffer */
#define SWD_THRESHOLD 2 /* lower limit for match length */
#define SWD_F 2048 /* upper limit for match length */
#define LZO1B 1
#define LZO_COMPRESS_T lzo1b_999_t
#define lzo_swd_t lzo1b_999_swd_t
#include "lzo_mchw.ch"
/***********************************************************************
//
************************************************************************/
static lzo_bytep
code_match ( LZO_COMPRESS_T *c, lzo_bytep op, lzo_uint m_len, lzo_uint m_off )
{
if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
{
assert(m_len >= M2_MIN_LEN);
assert(m_off >= M2_MIN_OFFSET);
m_off -= M2_MIN_OFFSET;
/* code match len + low offset bits */
*op++ = LZO_BYTE(((m_len - (M2_MIN_LEN - 2)) << M2O_BITS) |
(m_off & M2O_MASK));
/* code high offset bits */
*op++ = LZO_BYTE(m_off >> M2O_BITS);
c->m2_m++;
}
else
{
assert(m_len >= M3_MIN_LEN);
assert(m_off <= M3_MAX_OFFSET);
m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET;
/* code match len */
if (m_len <= M3_MAX_LEN)
*op++ = LZO_BYTE(M3_MARKER | (m_len - (M3_MIN_LEN - 1)));
else
{
assert(m_len >= M4_MIN_LEN);
/* code M4 match len flag */
*op++ = M4_MARKER;
/* code match len */
m_len -= M4_MIN_LEN - 1;
while (m_len > 255)
{
m_len -= 255;
*op++ = 0;
}
assert(m_len > 0);
*op++ = LZO_BYTE(m_len);
}
/* code low offset bits */
*op++ = LZO_BYTE(m_off & M3O_MASK);
/* code high offset bits */
*op++ = LZO_BYTE(m_off >> M3O_BITS);
c->r1_m_len = 0;
c->m3_m++;
}
return op;
}
/***********************************************************************
// this is a public function, but there is no prototype in a header file
************************************************************************/
LZO_EXTERN(int)
lzo1b_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)
lzo1b_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;
const lzo_bytep ii;
lzo_uint lit;
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;
/* sanity check */
LZO_COMPILE_TIME_ASSERT(LZO1B_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->r1_r = c->m3_r = c->m2_m = c->m3_m = 0;
op = out;
ii = c->ip; /* point to start of literal run */
lit = 0;
c->r1_m_len = 0;
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)
{
int lazy_match_min_gain = -1;
lzo_uint ahead = 0;
m_len = c->m_len;
m_off = c->m_off;
#if 0
printf("%5ld: %5d len:%3d off:%5d\n", (c->ip-c->look)-in, c->look,
m_len, m_off);
#endif
assert(c->ip - c->look >= in);
if (lit == 0)
ii = c->ip - c->look;
assert(ii + lit == c->ip - c->look);
assert(swd->b_char == *(c->ip - c->look));
if ((m_len < M2_MIN_LEN) ||
(m_len < M3_MIN_LEN && m_off > M2_MAX_OFFSET))
{
m_len = 0;
}
else
{
assert(c->ip - c->look - m_off >= in);
assert(c->ip - c->look - m_off + m_len < c->ip);
assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
m_len) == 0);
if (lit > 0)
{
/* we have a current literal run: do not try a lazy match,
if the literal could be coded into a r1 match */
if (lit == 1 && c->r1_m_len == M2_MIN_LEN)
lazy_match_min_gain = -1;
else
lazy_match_min_gain = 1;
#if (M2_MIN_LEN == 2)
if (m_len == 2)
{
/* don't code a match of len 2 if we have to
code a literal run. Code a literal instead. */
m_len = 0;
}
#endif
#if (M2_MIN_LEN == M3_MIN_LEN)
if (m_len == M2_MIN_LEN && m_off > M2_MAX_OFFSET)
{
/* don't code a M3 match of len 3 if we have to
code a literal run. Code a literal instead. */
m_len = 0;
}
#endif
}
else
{
/* no current literal run: only try a lazy match,
if the literal could be coded into a r1 match */
if (c->r1_m_len == M2_MIN_LEN)
lazy_match_min_gain = 0;
else
lazy_match_min_gain = -1;
}
}
/* try a lazy match */
if (m_len == 0)
lazy_match_min_gain = -1;
if (lazy_match_min_gain >= 0 && c->look > m_len)
{
assert(m_len > 0);
r = find_match(c,swd,1,0);
assert(r == 0); LZO_UNUSED(r);
assert(c->look > 0);
if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET &&
c->m_off > M2_MAX_OFFSET)
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);
#endif
lit++;
assert(ii + lit == c->ip - c->look);
continue;
}
else
{
ahead = 1;
assert(ii + lit + 1 == c->ip - c->look);
}
assert(m_len > 0);
}
assert(ii + lit + ahead == c->ip - c->look);
if (m_len == 0)
{
/* a literal */
lit++;
r = find_match(c,swd,1,0);
assert(r == 0); LZO_UNUSED(r);
}
else
{
/* 1 - store run */
if (lit > 0)
{
/* code current literal run */
if (lit == 1 && c->r1_m_len == M2_MIN_LEN)
{
/* Code a context sensitive R1 match. */
assert((op[-2] >> M2O_BITS) == (M2_MARKER >> M2O_BITS));
op[-2] &= M2O_MASK;
assert((op[-2] >> M2O_BITS) == 0);
/* copy 1 literal */
*op++ = *ii++;
assert(ii + ahead == c->ip - c->look);
c->r1_r++;
}
else
{
op = STORE_RUN(op,ii,lit);
}
if (lit < R0FAST)
c->r1_m_len = m_len;
else
c->r1_m_len = 0;
lit = 0;
}
else
c->r1_m_len = 0;
/* 2 - code match */
op = code_match(c,op,m_len,m_off);
r = find_match(c,swd,m_len,1+ahead);
assert(r == 0); LZO_UNUSED(r);
}
c->codesize = pd(op, out);
}
/* store final run */
if (lit > 0)
op = STORE_RUN(op,ii,lit);
#if defined(LZO_EOF_CODE)
*op++ = M3_MARKER | 1;
*op++ = 0;
*op++ = 0;
#endif
c->codesize = pd(op, out);
assert(c->textsize == in_len);
*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)in_len, (long) c->codesize,
c->r1_r, c->m3_r, c->m2_m, c->m3_m, c->lazy);
#endif
return LZO_E_OK;
}
/***********************************************************************
//
************************************************************************/
LZO_PUBLIC(int)
lzo1b_999_compress ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem )
{
return lzo1b_999_compress_callback(in,in_len,out,out_len,wrkmem,
(lzo_callback_p) 0, 0);
}
/*
vi:ts=4:et
*/
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