File: fast_encoder.c

package info (click to toggle)
clzip 1.11-5
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, sid
  • size: 536 kB
  • sloc: ansic: 3,986; sh: 503; makefile: 118
file content (191 lines) | stat: -rw-r--r-- 6,876 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
/*  Clzip - LZMA lossless data compressor
    Copyright (C) 2010-2019 Antonio Diaz Diaz.

    This program 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.

    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#define _FILE_OFFSET_BITS 64

#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "lzip.h"
#include "encoder_base.h"
#include "fast_encoder.h"


int FLZe_longest_match_len( struct FLZ_encoder * const fe, int * const distance )
  {
  enum { len_limit = 16 };
  const uint8_t * const data = Mb_ptr_to_current_pos( &fe->eb.mb );
  int32_t * ptr0 = fe->eb.mb.pos_array + fe->eb.mb.cyclic_pos;
  const int pos1 = fe->eb.mb.pos + 1;
  int maxlen = 0, newpos1, count;
  const int available = min( Mb_available_bytes( &fe->eb.mb ), max_match_len );
  if( available < len_limit ) return 0;

  fe->key4 = ( ( fe->key4 << 4 ) ^ data[3] ) & fe->eb.mb.key4_mask;
  newpos1 = fe->eb.mb.prev_positions[fe->key4];
  fe->eb.mb.prev_positions[fe->key4] = pos1;

  for( count = 4; ; )
    {
    int32_t * newptr;
    int delta;
    if( newpos1 <= 0 || --count < 0 ||
        ( delta = pos1 - newpos1 ) > fe->eb.mb.dictionary_size )
      { *ptr0 = 0; break; }
    newptr = fe->eb.mb.pos_array +
      ( fe->eb.mb.cyclic_pos - delta +
        ( ( fe->eb.mb.cyclic_pos >= delta ) ? 0 : fe->eb.mb.dictionary_size + 1 ) );

    if( data[maxlen-delta] == data[maxlen] )
      {
      int len = 0;
      while( len < available && data[len-delta] == data[len] ) ++len;
      if( maxlen < len )
        { maxlen = len; *distance = delta - 1;
          if( maxlen >= len_limit ) { *ptr0 = *newptr; break; } }
      }

    *ptr0 = newpos1;
    ptr0 = newptr;
    newpos1 = *ptr0;
    }
  return maxlen;
  }


bool FLZe_encode_member( struct FLZ_encoder * const fe,
                         const unsigned long long member_size )
  {
  const unsigned long long member_size_limit =
    member_size - Lt_size - max_marker_size;
  int rep = 0, i;
  int reps[num_rep_distances];
  State state = 0;
  for( i = 0; i < num_rep_distances; ++i ) reps[i] = 0;

  if( Mb_data_position( &fe->eb.mb ) != 0 ||
      Re_member_position( &fe->eb.renc ) != Lh_size )
    return false;				/* can be called only once */

  if( !Mb_data_finished( &fe->eb.mb ) )		/* encode first byte */
    {
    const uint8_t prev_byte = 0;
    const uint8_t cur_byte = Mb_peek( &fe->eb.mb, 0 );
    Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][0], 0 );
    LZeb_encode_literal( &fe->eb, prev_byte, cur_byte );
    CRC32_update_byte( &fe->eb.crc, cur_byte );
    FLZe_reset_key4( fe );
    FLZe_update_and_move( fe, 1 );
    }

  while( !Mb_data_finished( &fe->eb.mb ) &&
         Re_member_position( &fe->eb.renc ) < member_size_limit )
    {
    int match_distance;
    const int main_len = FLZe_longest_match_len( fe, &match_distance );
    const int pos_state = Mb_data_position( &fe->eb.mb ) & pos_state_mask;
    int len = 0;

    for( i = 0; i < num_rep_distances; ++i )
      {
      const int tlen = Mb_true_match_len( &fe->eb.mb, 0, reps[i] + 1 );
      if( tlen > len ) { len = tlen; rep = i; }
      }
    if( len > min_match_len && len + 3 > main_len )
      {
      CRC32_update_buf( &fe->eb.crc, Mb_ptr_to_current_pos( &fe->eb.mb ), len );
      Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][pos_state], 1 );
      Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[state], 1 );
      Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep0[state], rep != 0 );
      if( rep == 0 )
        Re_encode_bit( &fe->eb.renc, &fe->eb.bm_len[state][pos_state], 1 );
      else
        {
        int distance;
        Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep1[state], rep > 1 );
        if( rep > 1 )
          Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep2[state], rep > 2 );
        distance = reps[rep];
        for( i = rep; i > 0; --i ) reps[i] = reps[i-1];
        reps[0] = distance;
        }
      state = St_set_rep( state );
      Re_encode_len( &fe->eb.renc, &fe->eb.rep_len_model, len, pos_state );
      Mb_move_pos( &fe->eb.mb );
      FLZe_update_and_move( fe, len - 1 );
      continue;
      }

    if( main_len > min_match_len )
      {
      CRC32_update_buf( &fe->eb.crc, Mb_ptr_to_current_pos( &fe->eb.mb ), main_len );
      Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][pos_state], 1 );
      Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[state], 0 );
      state = St_set_match( state );
      for( i = num_rep_distances - 1; i > 0; --i ) reps[i] = reps[i-1];
      reps[0] = match_distance;
      LZeb_encode_pair( &fe->eb, match_distance, main_len, pos_state );
      Mb_move_pos( &fe->eb.mb );
      FLZe_update_and_move( fe, main_len - 1 );
      continue;
      }

    {
    const uint8_t prev_byte = Mb_peek( &fe->eb.mb, 1 );
    const uint8_t cur_byte = Mb_peek( &fe->eb.mb, 0 );
    const uint8_t match_byte = Mb_peek( &fe->eb.mb, reps[0] + 1 );
    Mb_move_pos( &fe->eb.mb );
    CRC32_update_byte( &fe->eb.crc, cur_byte );

    if( match_byte == cur_byte )
      {
      const int short_rep_price = price1( fe->eb.bm_match[state][pos_state] ) +
                                  price1( fe->eb.bm_rep[state] ) +
                                  price0( fe->eb.bm_rep0[state] ) +
                                  price0( fe->eb.bm_len[state][pos_state] );
      int price = price0( fe->eb.bm_match[state][pos_state] );
      if( St_is_char( state ) )
        price += LZeb_price_literal( &fe->eb, prev_byte, cur_byte );
      else
        price += LZeb_price_matched( &fe->eb, prev_byte, cur_byte, match_byte );
      if( short_rep_price < price )
        {
        Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][pos_state], 1 );
        Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[state], 1 );
        Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep0[state], 0 );
        Re_encode_bit( &fe->eb.renc, &fe->eb.bm_len[state][pos_state], 0 );
        state = St_set_short_rep( state );
        continue;
        }
      }

    /* literal byte */
    Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][pos_state], 0 );
    if( St_is_char( state ) )
      LZeb_encode_literal( &fe->eb, prev_byte, cur_byte );
    else
      LZeb_encode_matched( &fe->eb, prev_byte, cur_byte, match_byte );
    state = St_set_char( state );
    }
    }

  LZeb_full_flush( &fe->eb, state );
  return true;
  }