264 lines
6.2 KiB
Plaintext
264 lines
6.2 KiB
Plaintext
/* lzo1b_c.ch -- implementation of the LZO1B compression algorithm
|
|
|
|
This file is part of the LZO real-time data compression library.
|
|
|
|
Copyright (C) 1996-2002 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.,
|
|
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
|
|
Markus F.X.J. Oberhumer
|
|
<markus@oberhumer.com>
|
|
*/
|
|
|
|
|
|
|
|
/***********************************************************************
|
|
//
|
|
************************************************************************/
|
|
|
|
#if !defined(LZO_HAVE_R1) && !defined(LZO_NO_R1)
|
|
# define LZO_HAVE_R1
|
|
#endif
|
|
|
|
#if !defined(LZO_HAVE_M3) && !defined(LZO_NO_M3)
|
|
# if (M3O_BITS < 8)
|
|
# define LZO_HAVE_M3
|
|
# endif
|
|
#endif
|
|
|
|
|
|
#define MI
|
|
#define SI MI
|
|
#if (DD_BITS > 0)
|
|
#define DI ++ii; DVAL_NEXT(dv,ii); UPDATE_D(dict,drun,dv,ii,in); MI
|
|
#define XI assert(ii < ip); ii = ip; DVAL_FIRST(dv,(ip));
|
|
#else
|
|
#define DI ++ii; DINDEX1(dindex,ii); UPDATE_I(dict,0,dindex,ii,in); MI
|
|
#define XI assert(ii < ip); ii = ip;
|
|
#endif
|
|
|
|
|
|
/***********************************************************************
|
|
// compress a block of data.
|
|
//
|
|
// I really apologize for this spaghetti code.
|
|
************************************************************************/
|
|
|
|
LZO_PRIVATE(int)
|
|
do_compress ( const lzo_byte *in , lzo_uint in_len,
|
|
lzo_byte *out, lzo_uintp out_len,
|
|
lzo_voidp wrkmem )
|
|
{
|
|
/* this seems to work with buggy gcc */
|
|
/* #if defined(LZO_OPTIMIZE_GNUC_i386) */
|
|
#if 0 && defined(__GNUC__) && defined(__i386__)
|
|
register const lzo_byte *ip __asm__("%esi");
|
|
#else
|
|
register const lzo_byte *ip;
|
|
#endif
|
|
#if (DD_BITS > 0)
|
|
#if defined(__LZO_HASH_INCREMENTAL)
|
|
lzo_uint32 dv;
|
|
#endif
|
|
unsigned drun = 0;
|
|
#endif
|
|
lzo_byte *op;
|
|
const lzo_byte * const in_end = in + in_len;
|
|
const lzo_byte * const ip_end = in + in_len - MIN_LOOKAHEAD;
|
|
const lzo_byte *ii;
|
|
#if defined(LZO_HAVE_R1)
|
|
const lzo_byte *r1 = ip_end; /* pointer for R1 match (none yet) */
|
|
#endif
|
|
#if defined(LZO_HAVE_M3)
|
|
lzo_byte *m3 = out + 1; /* pointer after last m3/m4 match */
|
|
#endif
|
|
|
|
lzo_dict_p const dict = (lzo_dict_p) wrkmem;
|
|
|
|
|
|
#if defined(LZO_COLLECT_STATS)
|
|
lzo_stats->r_bits = R_BITS;
|
|
lzo_stats->m3o_bits = M3O_BITS;
|
|
lzo_stats->dd_bits = DD_BITS;
|
|
lzo_stats->clevel = CLEVEL;
|
|
lzo_stats->d_bits = D_BITS;
|
|
lzo_stats->min_lookahead = MIN_LOOKAHEAD;
|
|
lzo_stats->max_lookbehind = MAX_LOOKBEHIND;
|
|
lzo_stats->compress_id = _LZO_MEXPAND(COMPRESS_ID);
|
|
#endif
|
|
|
|
/* init dictionary */
|
|
#if defined(LZO_DETERMINISTIC)
|
|
BZERO8_PTR(wrkmem,sizeof(lzo_dict_t),D_SIZE);
|
|
#endif
|
|
|
|
|
|
op = out;
|
|
ip = in;
|
|
ii = ip; /* point to start of current literal run */
|
|
|
|
|
|
#if (DD_BITS > 0)
|
|
DVAL_FIRST(dv,ip);
|
|
UPDATE_D(dict,drun,dv,ip,in);
|
|
ip++;
|
|
DVAL_NEXT(dv,ip);
|
|
#else
|
|
ip++;
|
|
#endif
|
|
|
|
assert(ip < ip_end);
|
|
for (;;)
|
|
{
|
|
const lzo_byte *m_pos;
|
|
#if !defined(NDEBUG)
|
|
const lzo_byte *m_pos_sav = NULL;
|
|
#endif
|
|
lzo_moff_t m_off;
|
|
#if (DD_BITS == 0)
|
|
lzo_uint dindex;
|
|
#endif
|
|
lzo_uint m_len;
|
|
|
|
|
|
/***********************************************************************
|
|
// search for a match
|
|
************************************************************************/
|
|
|
|
#if !defined(LZO_SEARCH_MATCH_INCLUDE_FILE)
|
|
# define LZO_SEARCH_MATCH_INCLUDE_FILE "lzo1b_sm.ch"
|
|
#endif
|
|
|
|
#include LZO_SEARCH_MATCH_INCLUDE_FILE
|
|
|
|
|
|
#if !defined(LZO_TEST_MATCH_INCLUDE_FILE)
|
|
# define LZO_TEST_MATCH_INCLUDE_FILE "lzo1b_tm.ch"
|
|
#endif
|
|
|
|
#include LZO_TEST_MATCH_INCLUDE_FILE
|
|
|
|
|
|
|
|
/***********************************************************************
|
|
// found a literal
|
|
************************************************************************/
|
|
|
|
|
|
/* a literal */
|
|
literal:
|
|
#if (DD_BITS == 0)
|
|
UPDATE_I(dict,0,dindex,ip,in);
|
|
#endif
|
|
if (++ip >= ip_end)
|
|
break;
|
|
#if (DD_BITS > 0)
|
|
DVAL_NEXT(dv,ip);
|
|
#endif
|
|
continue;
|
|
|
|
|
|
|
|
/***********************************************************************
|
|
// found a match
|
|
************************************************************************/
|
|
|
|
match:
|
|
#if (DD_BITS == 0)
|
|
UPDATE_I(dict,0,dindex,ip,in);
|
|
#endif
|
|
/* we have found a match of at least M2_MIN_LEN */
|
|
|
|
|
|
#if !defined(LZO_CODE_RUN_INCLUDE_FILE)
|
|
# define LZO_CODE_RUN_INCLUDE_FILE "lzo1b_cr.ch"
|
|
#endif
|
|
|
|
#include LZO_CODE_RUN_INCLUDE_FILE
|
|
|
|
|
|
/* ii now points to the start of the current match */
|
|
assert(ii == ip);
|
|
|
|
|
|
/***********************************************************************
|
|
// code the match
|
|
************************************************************************/
|
|
|
|
#if !defined(LZO_CODE_MATCH_INCLUDE_FILE)
|
|
# define LZO_CODE_MATCH_INCLUDE_FILE "lzo1b_cm.ch"
|
|
#endif
|
|
|
|
#include LZO_CODE_MATCH_INCLUDE_FILE
|
|
|
|
|
|
/* ii now points to the start of the next literal run */
|
|
assert(ii == ip);
|
|
|
|
}
|
|
|
|
|
|
/***********************************************************************
|
|
// end of block
|
|
************************************************************************/
|
|
|
|
assert(ip <= in_end);
|
|
|
|
#if defined(LZO_COLLECT_STATS)
|
|
{
|
|
lzo_uint i;
|
|
const lzo_byte *p;
|
|
|
|
for (i = 0; i < D_SIZE; i++)
|
|
{
|
|
p = dict[i];
|
|
if (BOUNDS_CHECKING_OFF_IN_EXPR(p == NULL || p < in || p > in_end))
|
|
lzo_stats->unused_dict_entries++;
|
|
}
|
|
lzo_stats->unused_dict_entries_percent =
|
|
100.0 * lzo_stats->unused_dict_entries / D_SIZE;
|
|
}
|
|
#endif
|
|
|
|
|
|
#if defined(LZO_RETURN_IF_NOT_COMPRESSIBLE)
|
|
/* return if op == out to indicate that we
|
|
* couldn't compress and didn't copy anything.
|
|
*/
|
|
if (op == out)
|
|
{
|
|
*out_len = 0;
|
|
return LZO_E_NOT_COMPRESSIBLE;
|
|
}
|
|
#endif
|
|
|
|
/* store the final literal run */
|
|
if (pd(in_end,ii) > 0)
|
|
{
|
|
lzo_uint t = pd(in_end,ii);
|
|
op = STORE_RUN(op,ii,t);
|
|
}
|
|
|
|
*out_len = op - out;
|
|
return LZO_E_OK; /* compression went ok */
|
|
}
|
|
|
|
|
|
/*
|
|
vi:ts=4:et
|
|
*/
|