summaryrefslogtreecommitdiffstats
path: root/encoder.h
blob: 65c4403ed56f38dc29fb63f5481cacf1adfaf5be (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
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
/*  Clzip - LZMA lossless data compressor
    Copyright (C) 2010, 2011, 2012, 2013, 2014 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/>.
*/

enum { max_num_trials = 1 << 13,
       price_shift_bits = 6,
       price_step_bits = 2,
       price_step = 1 << price_step_bits };

typedef uint8_t Dis_slots[1<<10];

extern Dis_slots dis_slots;

static inline void Dis_slots_init( void )
  {
  int i, size, slot;
  for( slot = 0; slot < 4; ++slot ) dis_slots[slot] = slot;
  for( i = 4, size = 2, slot = 4; slot < 20; slot += 2 )
    {
    memset( &dis_slots[i], slot, size );
    memset( &dis_slots[i+size], slot + 1, size );
    size <<= 1;
    i += size;
    }
  }

static inline uint8_t get_slot( const unsigned dis )
  {
  if( dis < (1 << 10) ) return dis_slots[dis];
  if( dis < (1 << 19) ) return dis_slots[dis>> 9] + 18;
  if( dis < (1 << 28) ) return dis_slots[dis>>18] + 36;
  return dis_slots[dis>>27] + 54;
  }


typedef short Prob_prices[bit_model_total >> price_step_bits];

extern Prob_prices prob_prices;

static inline void Prob_prices_init( void )
  {
  int i, j;
  for( i = 0; i < bit_model_total >> price_step_bits; ++i )
    {
    unsigned val = ( i * price_step ) + ( price_step / 2 );
    int bits = 0;				/* base 2 logarithm of val */
    for( j = 0; j < price_shift_bits; ++j )
      {
      val = val * val;
      bits <<= 1;
      while( val >= 1 << 16 ) { val >>= 1; ++bits; }
      }
    bits += 15;					/* remaining bits in val */
    prob_prices[i] = ( bit_model_total_bits << price_shift_bits ) - bits;
    }
  }

static inline int get_price( const int probability )
  { return prob_prices[probability >> price_step_bits]; }


static inline int price0( const Bit_model probability )
  { return get_price( probability ); }

static inline int price1( const Bit_model probability )
  { return get_price( bit_model_total - probability ); }

static inline int price_bit( const Bit_model bm, const int bit )
  { if( bit ) return price1( bm ); else return price0( bm ); }


static inline int price_symbol( const Bit_model bm[], int symbol,
                                const int num_bits )
  {
  int price = 0;
  symbol |= ( 1 << num_bits );
  while( symbol > 1 )
    {
    const int bit = symbol & 1;
    symbol >>= 1;
    price += price_bit( bm[symbol], bit );
    }
  return price;
  }


static inline int price_symbol_reversed( const Bit_model bm[], int symbol,
                                         const int num_bits )
  {
  int price = 0;
  int model = 1;
  int i;
  for( i = num_bits; i > 0; --i )
    {
    const int bit = symbol & 1;
    price += price_bit( bm[model], bit );
    model = ( model << 1 ) | bit;
    symbol >>= 1;
    }
  return price;
  }


static inline int price_matched( const Bit_model bm[], int symbol,
                                 int match_byte )
  {
  int price = 0;
  int mask = 0x100;
  symbol |= mask;

  do {
    int match_bit, bit;
    match_byte <<= 1;
    match_bit = match_byte & mask;
    symbol <<= 1;
    bit = symbol & 0x100;
    price += price_bit( bm[match_bit+(symbol>>9)+mask], bit );
    mask &= ~(match_byte ^ symbol);	/* if( match_bit != bit ) mask = 0; */
    }
  while( symbol < 0x10000 );
  return price;
  }


struct Pair			/* distance-length pair */
  {
  int dis;
  int len;
  };


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

struct Matchfinder
  {
  unsigned long long partial_data_pos;
  uint8_t * buffer;		/* input buffer */
  int32_t * prev_positions;	/* 1 + last seen position of key. else 0 */
  int32_t * prev_pos_tree;	/* previous positions of key */
  int match_len_limit;
  int buffer_size;
  int dictionary_size;		/* bytes to keep in buffer before pos */
  int pos;			/* current pos in buffer */
  int cyclic_pos;		/* cycles through [0, dictionary_size] */
  int stream_pos;		/* first byte not yet read from file */
  int pos_limit;		/* when reached, a new block must be read */
  int cycles;
  int key4_mask;
  int num_prev_positions;	/* size of prev_positions */
  int infd;			/* input file descriptor */
  bool at_stream_end;		/* stream_pos shows real end of file */
  };

bool Mf_read_block( struct Matchfinder * const mf );
void Mf_normalize_pos( struct Matchfinder * const mf );

bool Mf_init( struct Matchfinder * const mf, const int dict_size,
              const int match_len_limit, const int ifd );

static inline void Mf_free( struct Matchfinder * const mf )
  {
  free( mf->prev_positions );
  free( mf->buffer );
  }

static inline uint8_t Mf_peek( const struct Matchfinder * const mf,
                               const int distance )
  { return mf->buffer[mf->pos-distance]; }

static inline int Mf_available_bytes( const struct Matchfinder * const mf )
  { return mf->stream_pos - mf->pos; }

static inline unsigned long long
Mf_data_position( const struct Matchfinder * const mf )
  { return mf->partial_data_pos + mf->pos; }

static inline bool Mf_finished( const struct Matchfinder * const mf )
  { return mf->at_stream_end && mf->pos >= mf->stream_pos; }

static inline const uint8_t *
Mf_ptr_to_current_pos( const struct Matchfinder * const mf )
  { return mf->buffer + mf->pos; }

static inline bool Mf_dec_pos( struct Matchfinder * const mf,
                               const int ahead )
  {
  if( ahead < 0 || mf->pos < ahead ) return false;
  mf->pos -= ahead;
  mf->cyclic_pos -= ahead;
  if( mf->cyclic_pos < 0 ) mf->cyclic_pos += mf->dictionary_size + 1;
  return true;
  }

static inline int Mf_true_match_len( const struct Matchfinder * const mf,
                                     const int index, const int distance,
                                     int len_limit )
  {
  const uint8_t * const data = mf->buffer + mf->pos + index;
  int i = 0;

  if( index + len_limit > Mf_available_bytes( mf ) )
    len_limit = Mf_available_bytes( mf ) - index;
  while( i < len_limit && data[i-distance] == data[i] ) ++i;
  return i;
  }

static inline void Mf_move_pos( struct Matchfinder * const mf )
  {
  if( ++mf->cyclic_pos > mf->dictionary_size ) mf->cyclic_pos = 0;
  if( ++mf->pos >= mf->pos_limit ) Mf_normalize_pos( mf );
  }

void Mf_reset( struct Matchfinder * const mf );
int Mf_get_match_pairs( struct Matchfinder * const mf, struct Pair * pairs );


enum { re_buffer_size = 65536 };

struct Range_encoder
  {
  uint64_t low;
  unsigned long long partial_member_pos;
  uint8_t * buffer;		/* output buffer */
  int pos;			/* current pos in buffer */
  uint32_t range;
  unsigned ff_count;
  int outfd;			/* output file descriptor */
  uint8_t cache;
  };

void Re_flush_data( struct Range_encoder * const renc );

static inline void Re_put_byte( struct Range_encoder * const renc,
                                const uint8_t b )
  {
  renc->buffer[renc->pos] = b;
  if( ++renc->pos >= re_buffer_size ) Re_flush_data( renc );
  }

static inline void Re_shift_low( struct Range_encoder * const renc )
  {
  const bool carry = ( renc->low > 0xFFFFFFFFU );
  if( carry || renc->low < 0xFF000000U )
    {
    Re_put_byte( renc, renc->cache + carry );
    for( ; renc->ff_count > 0; --renc->ff_count )
      Re_put_byte( renc, 0xFF + carry );
    renc->cache = renc->low >> 24;
    }
  else ++renc->ff_count;
  renc->low = ( renc->low & 0x00FFFFFFU ) << 8;
  }

static inline bool Re_init( struct Range_encoder * const renc, const int ofd )
  {
  renc->low = 0;
  renc->partial_member_pos = 0;
  renc->buffer = (uint8_t *)malloc( re_buffer_size );
  if( !renc->buffer ) return false;
  renc->pos = 0;
  renc->range = 0xFFFFFFFFU;
  renc->ff_count = 0;
  renc->outfd = ofd;
  renc->cache = 0;
  return true;
  }

static inline void Re_free( struct Range_encoder * const renc )
  { free( renc->buffer ); }

static inline unsigned long long
Re_member_position( const struct Range_encoder * const renc )
  { return renc->partial_member_pos + renc->pos + renc->ff_count; }

static inline void Re_flush( struct Range_encoder * const renc )
  { int i; for( i = 0; i < 5; ++i ) Re_shift_low( renc ); }

static inline void Re_encode( struct Range_encoder * const renc,
                              const int symbol, const int num_bits )
  {
  int i;
  for( i = num_bits - 1; i >= 0; --i )
    {
    renc->range >>= 1;
    if( (symbol >> i) & 1 ) renc->low += renc->range;
    if( renc->range <= 0x00FFFFFFU )
      { renc->range <<= 8; Re_shift_low( renc ); }
    }
  }

static inline void Re_encode_bit( struct Range_encoder * const renc,
                                  Bit_model * const probability, const int bit )
  {
  const uint32_t bound = ( renc->range >> bit_model_total_bits ) * *probability;
  if( !bit )
    {
    renc->range = bound;
    *probability += (bit_model_total - *probability) >> bit_model_move_bits;
    }
  else
    {
    renc->low += bound;
    renc->range -= bound;
    *probability -= *probability >> bit_model_move_bits;
    }
  if( renc->range <= 0x00FFFFFFU )
    { renc->range <<= 8; Re_shift_low( renc ); }
  }

static inline void Re_encode_tree( struct Range_encoder * const renc,
                                   Bit_model bm[], const int symbol, const int num_bits )
  {
  int mask = ( 1 << ( num_bits - 1 ) );
  int model = 1;
  int i;
  for( i = num_bits; i > 0; --i, mask >>= 1 )
    {
    const int bit = ( symbol & mask );
    Re_encode_bit( renc, &bm[model], bit );
    model <<= 1;
    if( bit ) model |= 1;
    }
  }

static inline void Re_encode_tree_reversed( struct Range_encoder * const renc,
                                            Bit_model bm[], int symbol, const int num_bits )
  {
  int model = 1;
  int i;
  for( i = num_bits; i > 0; --i )
    {
    const int bit = symbol & 1;
    Re_encode_bit( renc, &bm[model], bit );
    model = ( model << 1 ) | bit;
    symbol >>= 1;
    }
  }

static inline void Re_encode_matched( struct Range_encoder * const renc,
                                      Bit_model bm[], int symbol,
                                      int match_byte )
  {
  int mask = 0x100;
  symbol |= mask;

  do {
    int match_bit, bit;
    match_byte <<= 1;
    match_bit = match_byte & mask;
    symbol <<= 1;
    bit = symbol & 0x100;
    Re_encode_bit( renc, &bm[match_bit+(symbol>>9)+mask], bit );
    mask &= ~(match_byte ^ symbol);	/* if( match_bit != bit ) mask = 0; */
    }
  while( symbol < 0x10000 );
  }

static inline void Re_encode_len( struct Range_encoder * const renc,
                                  struct Len_model * const lm,
                                  int symbol, const int pos_state )
  {
  bool bit = ( ( symbol -= min_match_len ) >= len_low_symbols );
  Re_encode_bit( renc, &lm->choice1, bit );
  if( !bit )
    Re_encode_tree( renc, lm->bm_low[pos_state], symbol, len_low_bits );
  else
    {
    bit = ( symbol >= len_low_symbols + len_mid_symbols );
    Re_encode_bit( renc, &lm->choice2, bit );
    if( !bit )
      Re_encode_tree( renc, lm->bm_mid[pos_state],
                      symbol - len_low_symbols, len_mid_bits );
    else
      Re_encode_tree( renc, lm->bm_high,
                      symbol - len_low_symbols - len_mid_symbols, len_high_bits );
    }
  }


struct Len_prices
  {
  const struct Len_model * lm;
  int len_symbols;
  int count;
  int prices[pos_states][max_len_symbols];
  int counters[pos_states];
  };

static inline void Lp_update_low_mid_prices( struct Len_prices * const lp,
                                             const int pos_state )
  {
  int * const pps = lp->prices[pos_state];
  int tmp = price0( lp->lm->choice1 );
  int len = 0;
  lp->counters[pos_state] = lp->count;
  for( ; len < len_low_symbols && len < lp->len_symbols; ++len )
    pps[len] = tmp + price_symbol( lp->lm->bm_low[pos_state], len, len_low_bits );
  if( len >= lp->len_symbols ) return;
  tmp = price1( lp->lm->choice1 ) + price0( lp->lm->choice2 );
  for( ; len < len_low_symbols + len_mid_symbols && len < lp->len_symbols; ++len )
    pps[len] = tmp +
               price_symbol( lp->lm->bm_mid[pos_state], len - len_low_symbols, len_mid_bits );
    }

static inline void Lp_update_high_prices( struct Len_prices * const lp )
  {
  const int tmp = price1( lp->lm->choice1 ) + price1( lp->lm->choice2 );
  int len;
  for( len = len_low_symbols + len_mid_symbols; len < lp->len_symbols; ++len )
    /* using 4 slots per value makes "Lp_price" faster */
    lp->prices[3][len] = lp->prices[2][len] =
    lp->prices[1][len] = lp->prices[0][len] = tmp +
      price_symbol( lp->lm->bm_high, len - len_low_symbols - len_mid_symbols, len_high_bits );
  }

static inline void Lp_init( struct Len_prices * const lp,
                            const struct Len_model * const lm,
                            const int match_len_limit )
  {
  int i;
  lp->lm = lm;
  lp->len_symbols = match_len_limit + 1 - min_match_len;
  lp->count = ( match_len_limit > 12 ) ? 1 : lp->len_symbols;
  for( i = 0; i < pos_states; ++i ) lp->counters[i] = 0;
  }

static inline void Lp_decrement_counter( struct Len_prices * const lp,
                                         const int pos_state )
  { --lp->counters[pos_state]; }

static inline void Lp_update_prices( struct Len_prices * const lp )
  {
  int pos_state;
  bool high_pending = false;
  for( pos_state = 0; pos_state < pos_states; ++pos_state )
    if( lp->counters[pos_state] <= 0 )
      { Lp_update_low_mid_prices( lp, pos_state ); high_pending = true; }
  if( high_pending && lp->len_symbols > len_low_symbols + len_mid_symbols )
    Lp_update_high_prices( lp );
  }

static inline int Lp_price( const struct Len_prices * const lp,
                            const int symbol, const int pos_state )
  { return lp->prices[pos_state][symbol - min_match_len]; }


enum { infinite_price = 0x0FFFFFFF,
       max_marker_size = 16,
       num_rep_distances = 4,			/* must be 4 */
       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];
  };

static inline void Tr_update( struct Trial * const trial, const int pr,
                              const int distance, const int p_i )
  {
  if( pr < trial->price )
    {
    trial->price = pr; trial->dis = distance; trial->prev_index = p_i;
    trial->prev_index2 = single_step_trial;
    }
  }

static inline void Tr_update2( struct Trial * const trial, const int pr,
                               const int p_i )
  {
  if( pr < trial->price )
    {
    trial->price = pr; trial->dis = 0; trial->prev_index = p_i;
    trial->prev_index2 = dual_step_trial;
    }
  }

static inline void Tr_update3( struct Trial * const trial, const int pr,
                               const int distance, const int p_i,
                               const int p_i2 )
  {
  if( pr < trial->price )
    {
    trial->price = pr; trial->dis = distance; trial->prev_index = p_i;
    trial->prev_index2 = p_i2;
    }
  }


struct LZ_encoder
  {
  int pending_num_pairs;
  uint32_t crc;

  Bit_model bm_literal[1<<literal_context_bits][0x300];
  Bit_model bm_match[states][pos_states];
  Bit_model bm_rep[states];
  Bit_model bm_rep0[states];
  Bit_model bm_rep1[states];
  Bit_model bm_rep2[states];
  Bit_model bm_len[states][pos_states];
  Bit_model bm_dis_slot[len_states][1<<dis_slot_bits];
  Bit_model bm_dis[modeled_distances-end_dis_model];
  Bit_model bm_align[dis_align_size];

  struct Matchfinder * matchfinder;
  struct Range_encoder renc;
  struct Len_model match_len_model;
  struct Len_model rep_len_model;
  struct Len_prices match_len_prices;
  struct Len_prices rep_len_prices;

  struct Pair pairs[max_match_len+1];
  struct 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];
  int num_dis_slots;
  };

bool LZe_init( struct LZ_encoder * const e, struct Matchfinder * const mf,
               const File_header header, const int outfd );

static inline void LZe_free( struct LZ_encoder * const e )
  { Re_free( &e->renc ); }

static inline unsigned LZe_crc( const struct LZ_encoder * const e )
  { return e->crc ^ 0xFFFFFFFFU; }

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

static inline int LZe_price_shortrep( const struct LZ_encoder * const e,
                                      const State state, const int pos_state )
  {
  return price0( e->bm_rep0[state] ) + price0( e->bm_len[state][pos_state] );
  }

static inline int LZe_price_rep( const struct LZ_encoder * const e,
                                 const int rep,
                                 const State state, const int pos_state )
  {
  int price;
  if( rep == 0 ) return price0( e->bm_rep0[state] ) +
                        price1( e->bm_len[state][pos_state] );
  price = price1( e->bm_rep0[state] );
  if( rep == 1 )
    price += price0( e->bm_rep1[state] );
  else
    {
    price += price1( e->bm_rep1[state] );
    price += price_bit( e->bm_rep2[state], rep - 2 );
    }
  return price;
  }

static inline int LZe_price_rep0_len( const struct LZ_encoder * const e,
                                      const int len,
                                      const State state, const int pos_state )
  {
  return LZe_price_rep( e, 0, state, pos_state ) +
         Lp_price( &e->rep_len_prices, len, pos_state );
  }

static inline int LZe_price_pair( const struct LZ_encoder * const e,
                                  const int dis, const int len,
                                  const int pos_state )
  {
  const int price = Lp_price( &e->match_len_prices, len, pos_state );
  const int len_state = get_len_state( len );
  if( dis < modeled_distances )
    return price + e->dis_prices[len_state][dis];
  else
    return price + e->dis_slot_prices[len_state][get_slot( dis )] +
           e->align_prices[dis & (dis_align_size - 1)];
  }

static inline int LZe_price_literal( const struct LZ_encoder * const e,
                                     uint8_t prev_byte, uint8_t symbol )
  { return price_symbol( e->bm_literal[get_lit_state(prev_byte)], symbol, 8 ); }

static inline int LZe_price_matched( const struct LZ_encoder * const e,
                                     uint8_t prev_byte, uint8_t symbol,
                                     uint8_t match_byte )
  { return price_matched( e->bm_literal[get_lit_state(prev_byte)], symbol,
                          match_byte ); }

static inline void LZe_encode_literal( struct LZ_encoder * const e,
                                       uint8_t prev_byte, uint8_t symbol )
  { Re_encode_tree( &e->renc,
                    e->bm_literal[get_lit_state(prev_byte)], symbol, 8 ); }

static inline void LZe_encode_matched( struct LZ_encoder * const e,
                                       uint8_t prev_byte, uint8_t symbol,
                                       uint8_t match_byte )
  { Re_encode_matched( &e->renc, e->bm_literal[get_lit_state(prev_byte)],
                       symbol, match_byte ); }

static inline void LZe_encode_pair( struct LZ_encoder * const e,
                                    const unsigned dis, const int len,
                                    const int pos_state )
  {
  const int dis_slot = get_slot( dis );
  Re_encode_len( &e->renc, &e->match_len_model, len, pos_state );
  Re_encode_tree( &e->renc, e->bm_dis_slot[get_len_state(len)], dis_slot,
                  dis_slot_bits );

  if( dis_slot >= start_dis_model )
    {
    const int direct_bits = ( dis_slot >> 1 ) - 1;
    const unsigned base = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
    const unsigned direct_dis = dis - base;

    if( dis_slot < end_dis_model )
      Re_encode_tree_reversed( &e->renc, e->bm_dis + base - dis_slot - 1,
                               direct_dis, direct_bits );
    else
      {
      Re_encode( &e->renc, direct_dis >> dis_align_bits,
                 direct_bits - dis_align_bits );
      Re_encode_tree_reversed( &e->renc, e->bm_align, direct_dis, dis_align_bits );
      }
    }
  }

static inline int LZe_read_match_distances( struct LZ_encoder * const e )
  {
  const int num_pairs = Mf_get_match_pairs( e->matchfinder, e->pairs );
  if( num_pairs > 0 )
    {
    int len = e->pairs[num_pairs-1].len;
    if( len == e->matchfinder->match_len_limit && len < max_match_len )
      {
      len += Mf_true_match_len( e->matchfinder, len,
                                e->pairs[num_pairs-1].dis + 1,
                                max_match_len - len );
      e->pairs[num_pairs-1].len = len;
      }
    }
  return num_pairs;
  }

static inline void LZe_move_pos( struct LZ_encoder * const e, int n )
  {
  while( true )
    {
    Mf_move_pos( e->matchfinder );
    if( --n <= 0 ) break;
    Mf_get_match_pairs( e->matchfinder, 0 );
    }
  }

static inline void LZe_backward( struct LZ_encoder * const e, int cur )
  {
  int * const dis = &e->trials[cur].dis;
  while( cur > 0 )
    {
    const int prev_index = e->trials[cur].prev_index;
    struct Trial * const prev_trial = &e->trials[prev_index];

    if( e->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( e->trials[cur].prev_index2 >= 0 )
        {
        struct Trial * const prev_trial2 = &e->trials[prev_index-1];
        prev_trial2->dis = *dis; *dis = 0;
        prev_trial2->prev_index = e->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;
    }
  }

bool LZe_encode_member( struct LZ_encoder * const e,
                        const unsigned long long member_size );