release/src/router/lzo/src/lzo1b_cc.c

   1 /* lzo1b_cc.c -- LZO1B compression internal entry point
   2
   3    This file is part of the LZO real-time data compression library.
   4
   5    Copyright (C) 2011 Markus Franz Xaver Johannes Oberhumer
   6    Copyright (C) 2010 Markus Franz Xaver Johannes Oberhumer
   7    Copyright (C) 2009 Markus Franz Xaver Johannes Oberhumer
   8    Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
   9    Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
  10    Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
  11    Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
  12    Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
  13    Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
  14    Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
  15    Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
  16    Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
  17    Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
  18    Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
  19    Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
  20    Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
  21    All Rights Reserved.
  22
  23    The LZO library is free software; you can redistribute it and/or
  24    modify it under the terms of the GNU General Public License as
  25    published by the Free Software Foundation; either version 2 of
  26    the License, or (at your option) any later version.
  27
  28    The LZO library is distributed in the hope that it will be useful,
  29    but WITHOUT ANY WARRANTY; without even the implied warranty of
  30    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  31    GNU General Public License for more details.
  32
  33    You should have received a copy of the GNU General Public License
  34    along with the LZO library; see the file COPYING.
  35    If not, write to the Free Software Foundation, Inc.,
  36    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  37
  38    Markus F.X.J. Oberhumer
  39    <markus@oberhumer.com>
  40    http://www.oberhumer.com/opensource/lzo/
  41  */
  42
  43
  44 #define LZO_NEED_DICT_H 1
  45 #include "config1b.h"
  46
  47
  48 /***********************************************************************
  49 // compression internal entry point.
  50 ************************************************************************/
  51
  52 int _lzo1b_do_compress   ( const lzo_bytep in,  lzo_uint  in_len,
  53                                  lzo_bytep out, lzo_uintp out_len,
  54                                  lzo_voidp wrkmem,
  55                                  lzo_compress_t func )
  56 {
  57     int r;
  58 #if defined(LZO_TEST_COMPRESS_OVERRUN)
  59     lzo_uint avail_out = *out_len;
  60 #endif
  61
  62
  63 #if (LZO_COLLECT_STATS)
  64     _lzo1b_stats_init(lzo_stats);
  65     lzo_stats->in_len = in_len;
  66 #endif
  67
  68
  69     /* don't try to compress a block that's too short */
  70     if (in_len == 0)
  71     {
  72         *out_len = 0;
  73         r = LZO_E_OK;
  74     }
  75     else if (in_len <= MIN_LOOKAHEAD + 1)
  76     {
  77 #if defined(LZO_RETURN_IF_NOT_COMPRESSIBLE)
  78         *out_len = 0;
  79         r = LZO_E_NOT_COMPRESSIBLE;
  80 #else
  81         *out_len = pd(STORE_RUN(out,in,in_len), out);
  82         r = (*out_len > in_len) ? LZO_E_OK : LZO_E_ERROR;
  83 #endif
  84     }
  85     else
  86         r = func(in,in_len,out,out_len,wrkmem);
  87
  88
  89 #if defined(LZO_EOF_CODE)
  90 #if defined(LZO_TEST_COMPRESS_OVERRUN)
  91     if (r == LZO_E_OK && avail_out - *out_len < 3)
  92         r = LZO_E_COMPRESS_OVERRUN;
  93 #endif
  94     if (r == LZO_E_OK)
  95     {
  96         lzo_bytep op = out + *out_len;
  97         op[0] = M3_MARKER | 1;
  98         op[1] = 0;
  99         op[2] = 0;
 100         *out_len += 3;
 101     }
 102 #endif
 103
 104
 105 #if (LZO_COLLECT_STATS)
 106     lzo_stats->out_len = *out_len;
 107     lzo_stats->match_bytes =
 108        1 * lzo_stats->m1_matches + 2 * lzo_stats->m2_matches +
 109        3 * lzo_stats->m3_matches + 4 * lzo_stats->m4_matches;
 110     _lzo1b_stats_calc(lzo_stats);
 111 #endif
 112
 113     return r;
 114 }
 115
 116
 117 /***********************************************************************
 118 // note: this is not thread safe, but as it is used for finetuning only
 119 //       we don't care
 120 ************************************************************************/
 121
 122 #undef lzo_stats
 123 /* lzo_stats_t is still defined */
 124
 125
 126 #if (LZO_COLLECT_STATS)
 127
 128 static lzo_stats_t lzo_statistics;
 129 lzo_stats_t * const lzo1b_stats = &lzo_statistics;
 130
 131
 132 void _lzo1b_stats_init(lzo_stats_t *lzo_stats)
 133 {
 134     lzo_memset(lzo_stats,0,sizeof(*lzo_stats));
 135 }
 136
 137
 138 void _lzo1b_stats_calc(lzo_stats_t *lzo_stats)
 139 {
 140     lzo_stats->matches =
 141        lzo_stats->m1_matches + lzo_stats->m2_matches +
 142        lzo_stats->m3_matches + lzo_stats->m4_matches;
 143
 144     lzo_stats->literal_overhead = lzo_stats->lit_runs +
 145        2 * (lzo_stats->r0short_runs + lzo_stats->r0fast_runs +
 146             lzo_stats->r0long_runs);
 147     lzo_stats->literal_bytes = lzo_stats->literals +
 148        lzo_stats->literal_overhead;
 149
 150 #if 0
 151     assert(lzo_stats->match_bytes + lzo_stats->literal_bytes ==
 152        lzo_stats->out_len);
 153 #endif
 154
 155     lzo_stats->m2_matches -= lzo_stats->r1_matches;
 156     lzo_stats->m2_match[M2_MIN_LEN] -= lzo_stats->r1_matches;
 157
 158     if (lzo_stats->literals > 0)
 159         lzo_stats->literal_overhead_percent =
 160            100.0 * lzo_stats->literal_overhead / lzo_stats->literals;
 161 }
 162
 163
 164 #endif
 165
 166
 167 /*
 168 vi:ts=4:et
 169 */
 170