summaryrefslogtreecommitdiffstats
path: root/encoder.h
blob: 351c4ccc9b184ca917d28310d0c0c0b03e272e42 (plain)
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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
/*  Lzip - LZMA lossless data compressor
    Copyright (C) 2008-2016 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/>.
*/

class Len_prices
  {
  const Len_model & lm;
  const int len_symbols;
  const int count;
  int prices[pos_states][max_len_symbols];
  int counters[pos_states];

  void update_low_mid_prices( const int pos_state )
    {
    counters[pos_state] = count;
    int * const pps = prices[pos_state];
    int tmp = price0( lm.choice1 );
    int len = 0;
    for( ; len < len_low_symbols && len < len_symbols; ++len )
      pps[len] = tmp + price_symbol3( lm.bm_low[pos_state], len );
    if( len >= len_symbols ) return;
    tmp = price1( lm.choice1 ) + price0( lm.choice2 );
    for( ; len < len_low_symbols + len_mid_symbols && len < len_symbols; ++len )
      pps[len] = tmp +
                 price_symbol3( lm.bm_mid[pos_state], len - len_low_symbols );
    }

  void update_high_prices()
    {
    const int tmp = price1( lm.choice1 ) + price1( lm.choice2 );
    for( int len = len_low_symbols + len_mid_symbols; len < len_symbols; ++len )
      // using 4 slots per value makes "price" faster
      prices[3][len] = prices[2][len] = prices[1][len] = prices[0][len] = tmp +
        price_symbol8( lm.bm_high, len - len_low_symbols - len_mid_symbols );
    }

public:
  void reset() { for( int i = 0; i < pos_states; ++i ) counters[i] = 0; }

  Len_prices( const Len_model & m, const int match_len_limit )
    :
    lm( m ),
    len_symbols( match_len_limit + 1 - min_match_len ),
    count( ( match_len_limit > 12 ) ? 1 : len_symbols )
    { reset(); }

  void decrement_counter( const int pos_state ) { --counters[pos_state]; }

  void update_prices()
    {
    bool high_pending = false;
    for( int pos_state = 0; pos_state < pos_states; ++pos_state )
      if( counters[pos_state] <= 0 )
        { update_low_mid_prices( pos_state ); high_pending = true; }
    if( high_pending && len_symbols > len_low_symbols + len_mid_symbols )
      update_high_prices();
    }

  int price( const int symbol, const int pos_state ) const
    { return prices[pos_state][symbol - min_match_len]; }
  };


class LZ_encoder : public LZ_encoder_base
  {
  struct Pair			// distance-length pair
    {
    int dis;
    int len;
    };

  enum { infinite_price = 0x0FFFFFFF,
         max_num_trials = 1 << 13,
         single_step_trial = -2,
         dual_step_trial = -1 };

  struct Trial
    {
    State state;
    int price;		// dual use var; cumulative price, match length
    int dis;		// rep index or match distance. (-1 for literal)
    int prev_index;	// index of prev trial in trials[]
    int prev_index2;	//   -2  trial is single step
			//   -1  literal + rep0
			// >= 0  ( rep or match ) + literal + rep0
    int reps[num_rep_distances];

    void update( const int pr, const int distance, const int p_i )
      {
      if( pr < price )
        { price = pr; dis = distance; prev_index = p_i;
          prev_index2 = single_step_trial; }
      }

    void update2( const int pr, const int p_i )
      {
      if( pr < price )
        { price = pr; dis = 0; prev_index = p_i;
          prev_index2 = dual_step_trial; }
      }

    void update3( const int pr, const int distance, const int p_i,
                  const int p_i2 )
      {
      if( pr < price )
        { price = pr; dis = distance; prev_index = p_i; prev_index2 = p_i2; }
      }
    };

  const int cycles;
  const int match_len_limit;
  Len_prices match_len_prices;
  Len_prices rep_len_prices;
  int pending_num_pairs;
  Pair pairs[max_match_len+1];
  Trial trials[max_num_trials];

  int dis_slot_prices[len_states][2*max_dictionary_bits];
  int dis_prices[len_states][modeled_distances];
  int align_prices[dis_align_size];
  const int num_dis_slots;

  bool dec_pos( const int ahead )
    {
    if( ahead < 0 || pos < ahead ) return false;
    pos -= ahead;
    cyclic_pos -= ahead;
    if( cyclic_pos < 0 ) cyclic_pos += dictionary_size + 1;
    return true;
    }

  int get_match_pairs( Pair * pairs = 0 );
  void update_distance_prices();

       // move-to-front dis in/into reps if( dis > 0 )
  static void mtf_reps( const int dis, int reps[num_rep_distances] )
    {
    if( dis >= num_rep_distances )
      {
      for( int i = num_rep_distances - 1; i > 0; --i ) reps[i] = reps[i-1];
      reps[0] = dis - num_rep_distances;
      }
    else if( dis > 0 )
      {
      const int distance = reps[dis];
      for( int i = dis; i > 0; --i ) reps[i] = reps[i-1];
      reps[0] = distance;
      }
    }

  int price_shortrep( const State state, const int pos_state ) const
    {
    return price0( bm_rep0[state()] ) + price0( bm_len[state()][pos_state] );
    }

  int price_rep( const int rep, const State state, const int pos_state ) const
    {
    if( rep == 0 ) return price0( bm_rep0[state()] ) +
                          price1( bm_len[state()][pos_state] );
    int price = price1( bm_rep0[state()] );
    if( rep == 1 )
      price += price0( bm_rep1[state()] );
    else
      {
      price += price1( bm_rep1[state()] );
      price += price_bit( bm_rep2[state()], rep - 2 );
      }
    return price;
    }

  int price_rep0_len( const int len, const State state, const int pos_state ) const
    {
    return price_rep( 0, state, pos_state ) +
           rep_len_prices.price( len, pos_state );
    }

  int price_pair( const int dis, const int len, const int pos_state ) const
    {
    const int price = match_len_prices.price( len, pos_state );
    const int len_state = get_len_state( len );
    if( dis < modeled_distances )
      return price + dis_prices[len_state][dis];
    else
      return price + dis_slot_prices[len_state][get_slot( dis )] +
             align_prices[dis & (dis_align_size - 1)];
    }

  int read_match_distances()
    {
    const int num_pairs = get_match_pairs( pairs );
    if( num_pairs > 0 )
      {
      int len = pairs[num_pairs-1].len;
      if( len == match_len_limit && len < max_match_len )
        {
        len += true_match_len( len, pairs[num_pairs-1].dis + 1,
                               max_match_len - len );
        pairs[num_pairs-1].len = len;
        }
      }
    return num_pairs;
    }

  void move_and_update( int n )
    {
    while( true )
      {
      move_pos();
      if( --n <= 0 ) break;
      get_match_pairs();
      }
    }

  void backward( int cur )
    {
    int & dis = trials[cur].dis;
    while( cur > 0 )
      {
      const int prev_index = trials[cur].prev_index;
      Trial & prev_trial = trials[prev_index];

      if( trials[cur].prev_index2 != single_step_trial )
        {
        prev_trial.dis = -1;
        prev_trial.prev_index = prev_index - 1;
        prev_trial.prev_index2 = single_step_trial;
        if( trials[cur].prev_index2 >= 0 )
          {
          Trial & prev_trial2 = trials[prev_index-1];
          prev_trial2.dis = dis; dis = 0;
          prev_trial2.prev_index = trials[cur].prev_index2;
          prev_trial2.prev_index2 = single_step_trial;
          }
        }
      prev_trial.price = cur - prev_index;			// len
      cur = dis; dis = prev_trial.dis; prev_trial.dis = cur;
      cur = prev_index;
      }
    }

  int sequence_optimizer( const int reps[num_rep_distances],
                          const State state );

  enum { before = max_num_trials + 1,
         // bytes to keep in buffer after pos
         after_size = ( 2 * max_match_len ) + 1,
         dict_factor = 2,
         num_prev_positions3 = 1 << 16,
         num_prev_positions2 = 1 << 10,
         num_prev_positions23 = num_prev_positions2 + num_prev_positions3,
         pos_array_factor = 2 };

public:
  LZ_encoder( const int dict_size, const int len_limit,
              const int ifd, const int outfd )
    :
    LZ_encoder_base( before, dict_size, after_size, dict_factor,
                     num_prev_positions23, pos_array_factor, ifd, outfd ),
    cycles( ( len_limit < max_match_len ) ? 16 + ( len_limit / 2 ) : 256 ),
    match_len_limit( len_limit ),
    match_len_prices( match_len_model, match_len_limit ),
    rep_len_prices( rep_len_model, match_len_limit ),
    pending_num_pairs( 0 ),
    num_dis_slots( 2 * real_bits( dictionary_size - 1 ) )
    {
    trials[1].prev_index = 0;
    trials[1].prev_index2 = single_step_trial;
    }

  void reset()
    {
    LZ_encoder_base::reset();
    match_len_prices.reset();
    rep_len_prices.reset();
    pending_num_pairs = 0;
    }

  bool encode_member( const unsigned long long member_size );
  };