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/* lzo1b_c.ch -- implementation of the LZO1B 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/
*/
/***********************************************************************
//
************************************************************************/
#if !defined(LZO_HAVE_R1) && !defined(LZO_NO_R1)
# define LZO_HAVE_R1 1
#endif
#if !defined(LZO_HAVE_M3) && !defined(LZO_NO_M3)
# if (M3O_BITS < 8)
# define LZO_HAVE_M3 1
# endif
#endif
#define MI /*empty*/
#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.
************************************************************************/
#ifdef __cplusplus
extern "C" {
#endif
LZO_PRIVATE(int)
do_compress ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem )
{
const lzo_bytep ip;
#if (DD_BITS > 0)
#if defined(__LZO_HASH_INCREMENTAL)
lzo_xint dv;
#endif
unsigned drun = 0;
#endif
lzo_bytep op;
const lzo_bytep const in_end = in + in_len;
const lzo_bytep const ip_end = in + in_len - MIN_LOOKAHEAD;
const lzo_bytep ii;
#if defined(LZO_HAVE_R1)
const lzo_bytep r1 = ip_end; /* pointer for R1 match (none yet) */
#endif
#if defined(LZO_HAVE_M3)
lzo_bytep m3 = out + 1; /* pointer after last m3/m4 match */
#endif
lzo_dict_p const dict = (lzo_dict_p) wrkmem;
#if (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_PP_MACRO_EXPAND(COMPRESS_ID);
#endif
/* init dictionary */
#if (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_bytep m_pos;
#if !defined(NDEBUG)
const lzo_bytep m_pos_sav = NULL;
#endif
LZO_DEFINE_UNINITIALIZED_VAR(lzo_uint, m_off, 0);
#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 (LZO_COLLECT_STATS)
{
lzo_uint i;
const lzo_bytep 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 = pd(op, out);
return LZO_E_OK; /* compression went ok */
}
#ifdef __cplusplus
} /* extern "C" */
#endif
/*
vi:ts=4:et
*/
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