Repository navigation
Expand file tree
/
Copy pathlzma_decoder.c
More file actions
1064 lines (890 loc) · 26.7 KB
/
Copy pathlzma_decoder.c
File metadata and controls
1064 lines (890 loc) · 26.7 KB
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
64
10BC8
1
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
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
///////////////////////////////////////////////////////////////////////////////
//
/// \file lzma_decoder.c
/// \brief LZMA decoder
///
// Authors: Igor Pavlov
// Lasse Collin
//
// This file has been put into the public domain.
// You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////
#include "lz_decoder.h"
#include "lzma_common.h"
#include "lzma_decoder.h"
#include "range_decoder.h"
// The macros unroll loops with switch statements.
// Silence warnings about missing fall-through comments.
#if TUKLIB_GNUC_REQ(7, 0)
# pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
#endif
#ifdef HAVE_SMALL
// Macros for (somewhat) size-optimized code.
#define seq_4(seq) seq
#define seq_6(seq) seq
#define seq_8(seq) seq
#define seq_len(seq) \
seq ## _CHOICE, \
seq ## _CHOICE2, \
seq ## _BITTREE
#define len_decode(target, ld, pos_state, seq) \
do { \
case seq ## _CHOICE: \
rc_if_0(ld.choice, seq ## _CHOICE) { \
rc_update_0(ld.choice); \
probs = ld.low[pos_state];\
limit = LEN_LOW_SYMBOLS; \
target = MATCH_LEN_MIN; \
} else { \
rc_update_1(ld.choice); \
case seq ## _CHOICE2: \
rc_if_0(ld.choice2, seq ## _CHOICE2) { \
rc_update_0(ld.choice2); \
probs = ld.mid[pos_state]; \
limit = LEN_MID_SYMBOLS; \
target = MATCH_LEN_MIN + LEN_LOW_SYMBOLS; \
} else { \
rc_update_1(ld.choice2); \
probs = ld.high; \
limit = LEN_HIGH_SYMBOLS; \
target = MATCH_LEN_MIN + LEN_LOW_SYMBOLS \
+ LEN_MID_SYMBOLS; \
} \
} \
symbol = 1; \
case seq ## _BITTREE: \
do { \
rc_bit(probs[symbol], , , seq ## _BITTREE); \
} while (symbol < limit); \
target += symbol - limit; \
} while (0)
#else // HAVE_SMALL
// Unrolled versions
#define seq_4(seq) \
seq ## 0, \
seq ## 1, \
seq ## 2, \
seq ## 3
#define seq_6(seq) \
seq ## 0, \
seq ## 1, \
seq ## 2, \
seq ## 3, \
seq ## 4, \
seq ## 5
#define seq_8(seq) \
seq ## 0, \
seq ## 1, \
seq ## 2, \
seq ## 3, \
seq ## 4, \
seq ## 5, \
seq ## 6, \
seq ## 7
#define seq_len(seq) \
seq ## _CHOICE, \
seq ## _LOW0, \
seq ## _LOW1, \
seq ## _LOW2, \
seq ## _CHOICE2, \
seq ## _MID0, \
seq ## _MID1, \
seq ## _MID2, \
seq ## _HIGH0, \
seq ## _HIGH1, \
seq ## _HIGH2, \
seq ## _HIGH3, \
seq ## _HIGH4, \
seq ## _HIGH5, \
seq ## _HIGH6, \
seq ## _HIGH7
#define len_decode(target, ld, pos_state, seq) \
do { \
symbol = 1; \
case seq ## _CHOICE: \
rc_if_0(ld.choice, seq ## _CHOICE) { \
rc_update_0(ld.choice); \
rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW0); \
rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW1); \
rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW2); \
target = symbol - LEN_LOW_SYMBOLS + MATCH_LEN_MIN; \
} else { \
rc_update_1(ld.choice); \
case seq ## _CHOICE2: \
rc_if_0(ld.choice2, seq ## _CHOICE2) { \
rc_update_0(ld.choice2); \
rc_bit_case(ld.mid[pos_state][symbol], , , \
seq ## _MID0); \
rc_bit_case(ld.mid[pos_state][symbol], , , \
seq ## _MID1); \
rc_bit_case(ld.mid[pos_state][symbol], , , \
seq ## _MID2); \
target = symbol - LEN_MID_SYMBOLS \
+ MATCH_LEN_MIN + LEN_LOW_SYMBOLS; \
} else { \
rc_update_1(ld.choice2); \
rc_bit_case(ld.high[symbol], , , seq ## _HIGH0); \
rc_bit_case(ld.high[symbol], , , seq ## _HIGH1); \
rc_bit_case(ld.high[symbol], , , seq ## _HIGH2); \
rc_bit_case(ld.high[symbol], , , seq ## _HIGH3); \
rc_bit_case(ld.high[symbol], , , seq ## _HIGH4); \
rc_bit_case(ld.high[symbol], , , seq ## _HIGH5); \
rc_bit_case(ld.high[symbol], , , seq ## _HIGH6); \
rc_bit_case(ld.high[symbol], , , seq ## _HIGH7); \
target = symbol - LEN_HIGH_SYMBOLS \
+ MATCH_LEN_MIN \
+ LEN_LOW_SYMBOLS + LEN_MID_SYMBOLS; \
} \
} \
} while (0)
#endif // HAVE_SMALL
/// Length decoder probabilities; see comments in lzma_common.h.
typedef struct {
probability choice;
probability choice2;
probability low[POS_STATES_MAX][LEN_LOW_SYMBOLS];
probability mid[POS_STATES_MAX][LEN_MID_SYMBOLS];
probability high[LEN_HIGH_SYMBOLS];
} lzma_length_decoder;
typedef struct {
///////////////////
// Probabilities //
///////////////////
/// Literals; see comments in lzma_common.h.
probability literal[LITERAL_CODERS_MAX][LITERAL_CODER_SIZE];
/// If 1, it's a match. Otherwise it's a single 8-bit literal.
probability is_match[STATES][POS_STATES_MAX];
/// If 1, it's a repeated match. The distance is one of rep0 .. rep3.
probability is_rep[STATES];
/// If 0, distance of a repeated match is rep0.
/// Otherwise check is_rep1.
probability is_rep0[STATES];
/// If 0, distance of a repeated match is rep1.
/// Otherwise check is_rep2.
probability is_rep1[STATES];
/// If 0, distance of a repeated match is rep2. Otherwise it is rep3.
probability is_rep2[STATES];
/// If 1, the repeated match has length of one byte. Otherwise
/// the length is decoded from rep_len_decoder.
probability is_rep0_long[STATES][POS_STATES_MAX];
/// Probability tree for the highest two bits of the match distance.
/// There is a separate probability tree for match lengths of
/// 2 (i.e. MATCH_LEN_MIN), 3, 4, and [5, 273].
probability dist_slot[DIST_STATES][DIST_SLOTS];
/// Probability trees for additional bits for match distance when the
/// distance is in the range [4, 127].
probability pos_special[FULL_DISTANCES - DIST_MODEL_END];
/// Probability tree for the lowest four bits of a match distance
/// that is equal to or greater than 128.
probability pos_align[ALIGN_SIZE];
/// Length of a normal match
lzma_length_decoder match_len_decoder;
/// Length of a repeated match
lzma_length_decoder rep_len_decoder;
///////////////////
// Decoder state //
///////////////////
// Range coder
lzma_range_decoder rc;
// Types of the most recently seen LZMA symbols
lzma_lzma_state state;
uint32_t rep0; ///< Distance of the latest match
uint32_t rep1; ///< Distance of second latest match
uint32_t rep2; ///< Distance of third latest match
uint32_t rep3; ///< Distance of fourth latest match
uint32_t pos_mask; // (1U << pb) - 1
uint32_t literal_context_bits;
uint32_t literal_pos_mask;
/// Uncompressed size as bytes, or LZMA_VLI_UNKNOWN if end of
/// payload marker is expected.
lzma_vli uncompressed_size;
////////////////////////////////
// State of incomplete symbol //
////////////////////////////////
/// Position where to continue the decoder loop
enum {
SEQ_NORMALIZE,
SEQ_IS_MATCH,
seq_8(SEQ_LITERAL),
seq_8(SEQ_LITERAL_MATCHED),
SEQ_LITERAL_WRITE,
SEQ_IS_REP,
seq_len(SEQ_MATCH_LEN),
seq_6(SEQ_DIST_SLOT),
SEQ_DIST_MODEL,
SEQ_DIRECT,
seq_4(SEQ_ALIGN),
SEQ_EOPM,
SEQ_IS_REP0,
SEQ_SHORTREP,
SEQ_IS_REP0_LONG,
SEQ_IS_REP1,
SEQ_IS_REP2,
seq_len(SEQ_REP_LEN),
SEQ_COPY,
} sequence;
/// Base of the current probability tree
probability *probs;
/// Symbol being decoded. This is also used as an index variable in
/// bittree decoders: probs[symbol]
uint32_t symbol;
/// Used as a loop termination condition on bittree decoders and
/// direct bits decoder.
uint32_t limit;
/// Matched literal decoder: 0x100 or 0 to help avoiding branches.
/// Bittree reverse decoders: Offset of the next bit: 1 << offset
uint32_t offset;
/// If decoding a literal: match byte.
/// If decoding a match: length of the match.
uint32_t len;
} lzma_lzma1_decoder;
static lzma_ret
lzma_decode(void *coder_ptr, lzma_dict *restrict dictptr,
const uint8_t *restrict in,
size_t *restrict in_pos, size_t in_size)
{
lzma_lzma1_decoder *restrict coder = coder_ptr;
////////////////////
// Initialization //
////////////////////
{
const lzma_ret ret = rc_read_init(
&coder->rc, in, in_pos, in_size);
if (ret != LZMA_STREAM_END)
return ret;
}
///////////////
// Variables //
///////////////
// Making local copies of often-used variables improves both
// speed and readability.
lzma_dict dict = *dictptr;
const size_t dict_start = dict.pos;
// Range decoder
rc_to_local(coder->rc, *in_pos);
// State
uint32_t state = coder->state;
uint32_t rep0 = coder->rep0;
uint32_t rep1 = coder->rep1;
uint32_t rep2 = coder->rep2;
uint32_t rep3 = coder->rep3;
const uint32_t pos_mask = coder->pos_mask;
// These variables are actually needed only if we last time ran
// out of input in the middle of the decoder loop.
probability *probs = coder->probs;
uint32_t symbol = coder->symbol;
uint32_t limit = coder->limit;
uint32_t offset = coder->offset;
uint32_t len = coder->len;
const uint32_t literal_pos_mask = coder->literal_pos_mask;
const uint32_t literal_context_bits = coder->literal_context_bits;
// Temporary variables
uint32_t pos_state = dict.pos & pos_mask;
lzma_ret ret = LZMA_OK;
// If uncompressed size is known, there must be no end of payload
// marker.
const bool no_eopm = coder->uncompressed_size
!= LZMA_VLI_UNKNOWN;
if (no_eopm && coder->uncompressed_size < dict.limit - dict.pos)
dict.limit = dict.pos + (size_t)(coder->uncompressed_size);
// The main decoder loop. The "switch" is used to restart the decoder at
// correct location. Once restarted, the "switch" is no longer used.
switch (coder->sequence)
while (true) {
// Calculate new pos_state. This is skipped on the first loop
// since we already calculated it when setting up the local
// variables.
pos_state = dict.pos & pos_mask;
case SEQ_NORMALIZE:
case SEQ_IS_MATCH:
if (unlikely(no_eopm && dict.pos == dict.limit))
break;
rc_if_0(coder->is_match[state][pos_state], SEQ_IS_MATCH) {
rc_update_0(coder->is_match[state][pos_state]);
// It's a literal i.e. a single 8-bit byte.
probs = literal_subcoder(coder->literal,
literal_context_bits, literal_pos_mask,
dict.pos, dict_get(&dict, 0));
symbol = 1;
if (is_literal_state(state)) {
// Decode literal without match byte.
#ifdef HAVE_SMALL
case SEQ_LITERAL:
do {
rc_bit(probs[symbol], , , SEQ_LITERAL);
} while (symbol < (1 << 8));
#else
rc_bit_case(probs[symbol], , , SEQ_LITERAL0);
rc_bit_case(probs[symbol], , , SEQ_LITERAL1);
rc_bit_case(probs[symbol], , , SEQ_LITERAL2);
rc_bit_case(probs[symbol], , , SEQ_LITERAL3);
rc_bit_case(probs[symbol], , , SEQ_LITERAL4);
rc_bit_case(probs[symbol], , , SEQ_LITERAL5);
rc_bit_case(probs[symbol], , , SEQ_LITERAL6);
rc_bit_case(probs[symbol], , , SEQ_LITERAL7);
#endif
} else {
// Decode literal with match byte.
//
// We store the byte we compare against
// ("
8
match by
10BC8
te") to "len" to minimize the
// number of variables we need to store
// between decoder calls.
len = dict_get(&dict, rep0) << 1;
// The usage of "offset" allows omitting some
// branches, which should give tiny speed
// improvement on some CPUs. "offset" gets
// set to zero if match_bit didn't match.
offset = 0x100;
#ifdef HAVE_SMALL
case SEQ_LITERAL_MATCHED:
do {
const uint32_t match_bit
= len & offset;
const uint32_t subcoder_index
= offset + match_bit
+ symbol;
rc_bit(probs[subcoder_index],
offset &= ~match_bit,
offset &= match_bit,
SEQ_LITERAL_MATCHED);
// It seems to be faster to do this
// here instead of putting it to the
// beginning of the loop and then
// putting the "case" in the middle
// of the loop.
len <<= 1;
} while (symbol < (1 << 8));
#else
// Unroll the loop.
uint32_t match_bit;
uint32_t subcoder_index;
# define d(seq) \
case seq: \
match_bit = len & offset; \
subcoder_index = offset + match_bit + symbol; \
rc_bit(probs[subcoder_index], \
offset &= ~match_bit, \
offset &= match_bit, \
seq)
d(SEQ_LITERAL_MATCHED0);
len <<= 1;
d(SEQ_LITERAL_MATCHED1);
len <<= 1;
d(SEQ_LITERAL_MATCHED2);
len <<= 1;
d(SEQ_LITERAL_MATCHED3);
len <<= 1;
d(SEQ_LITERAL_MATCHED4);
len <<= 1;
d(SEQ_LITERAL_MATCHED5);
len <<= 1;
d(SEQ_LITERAL_MATCHED6);
len <<= 1;
d(SEQ_LITERAL_MATCHED7);
# undef d
#endif
}
//update_literal(state);
// Use a lookup table to update to literal state,
// since compared to other state updates, this would
// need two branches.
static const lzma_lzma_state next_state[] = {
STATE_LIT_LIT,
STATE_LIT_LIT,
STATE_LIT_LIT,
STATE_LIT_LIT,
STATE_MATCH_LIT_LIT,
STATE_REP_LIT_LIT,
STATE_SHORTREP_LIT_LIT,
STATE_MATCH_LIT,
STATE_REP_LIT,
STATE_SHORTREP_LIT,
STATE_MATCH_LIT,
STATE_REP_LIT
};
state = next_state[state];
case SEQ_LITERAL_WRITE:
if (unlikely(dict_put(&dict, symbol))) {
coder->sequence = SEQ_LITERAL_WRITE;
goto out;
}
continue;
}
// Instead of a new byte we are going to get a byte range
// (distance and length) which will be repeated from our
// output history.
rc_update_1(coder->is_match[state][pos_state]);
case SEQ_IS_REP:
rc_if_0(coder->is_rep[state], SEQ_IS_REP) {
// Not a repeated match
rc_update_0(coder->is_rep[state]);
update_match(state);
// The latest three match distances are kept in
// memory in case there are repeated matches.
rep3 = rep2;
rep2 = rep1;
rep1 = rep0;
// Decode the length of the match.
len_decode(len, coder->match_len_decoder,
pos_state, SEQ_MATCH_LEN);
// Prepare to decode the highest two bits of the
// match distance.
probs = coder->dist_slot[get_dist_state(len)];
symbol = 1;
#ifdef HAVE_SMALL
case SEQ_DIST_SLOT:
do {
rc_bit(probs[symbol], , , SEQ_DIST_SLOT);
} while (symbol < DIST_SLOTS);
#else
rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT0);
rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT1);
rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT2);
rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT3);
rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT4);
rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT5);
#endif
// Get rid of the highest bit that was needed for
// indexing of the probability array.
symbol -= DIST_SLOTS;
assert(symbol <= 63);
if (symbol < DIST_MODEL_START) {
// Match distances [0, 3] have only two bits.
rep0 = symbol;
} else {
// Decode the lowest [1, 29] bits of
// the match distance.
limit = (symbol >> 1) - 1;
assert(limit >= 1 && limit <= 30);
rep0 = 2 + (symbol & 1);
if (symbol < DIST_MODEL_END) {
// Prepare to decode the low bits for
// a distance of [4, 127].
assert(limit <= 5);
rep0 <<= limit;
assert(rep0 <= 96);
// -1 is fine, because we start
// decoding at probs[1], not probs[0].
// NOTE: This violates the C standard,
// since we are doing pointer
// arithmetic past the beginning of
// the array.
assert((int32_t)(rep0 - symbol - 1)
>= -1);
assert((int32_t)(rep0 - symbol - 1)
<= 82);
probs = coder->pos_special + rep0
- symbol - 1;
symbol = 1;
offset = 0;
case SEQ_DIST_MODEL:
#ifdef HAVE_SMALL
do {
rc_bit(probs[symbol], ,
rep0 += 1 << offset,
SEQ_DIST_MODEL);
} while (++offset < limit);
#else
switch (limit) {
case 5:
assert(offset == 0);
rc_bit(probs[symbol], ,
rep0 += 1,
SEQ_DIST_MODEL);
++offset;
--limit;
case 4:
rc_bit(probs[symbol], ,
rep0 += 1 << offset,
SEQ_DIST_MODEL);
++offset;
--limit;
case 3:
rc_bit(probs[symbol], ,
rep0 += 1 << offset,
SEQ_DIST_MODEL);
++offset;
--limit;
case 2:
rc_bit(probs[symbol], ,
rep0 += 1 << offset,
SEQ_DIST_MODEL);
++offset;
--limit;
case 1:
// We need "symbol" only for
// indexing the probability
// array, thus we can use
// rc_bit_last() here to omit
// the unneeded updating of
// "symbol".
rc_bit_last(probs[symbol], ,
rep0 += 1 << offset,
SEQ_DIST_MODEL);
}
#endif
} else {
// The distance is >= 128. Decode the
// lower bits without probabilities
// except the lowest four bits.
assert(symbol >= 14);
assert(limit >= 6);
limit -= ALIGN_BITS;
assert(limit >= 2);
case SEQ_DIRECT:
// Not worth manual unrolling
do {
rc_direct(rep0, SEQ_DIRECT);
} while (--limit > 0);
// Decode the lowest four bits using
// probabilities.
rep0 <<= ALIGN_BITS;
symbol = 1;
#ifdef HAVE_SMALL
offset = 0;
case SEQ_ALIGN:
do {
rc_bit(coder->pos_align[
symbol], ,
rep0 += 1 << offset,
SEQ_ALIGN);
} while (++offset < ALIGN_BITS);
#else
case SEQ_ALIGN0:
rc_bit(coder->pos_align[symbol], ,
rep0 += 1, SEQ_ALIGN0);
case SEQ_ALIGN1:
rc_bit(coder->pos_align[symbol], ,
rep0 += 2, SEQ_ALIGN1);
case SEQ_ALIGN2:
rc_bit(coder->pos_align[symbol], ,
rep0 += 4, SEQ_ALIGN2);
case SEQ_ALIGN3:
// Like in SEQ_DIST_MODEL, we don't
// need "symbol" for anything else
// than indexing the probability array.
rc_bit_last(coder->pos_align[symbol], ,
rep0 += 8, SEQ_ALIGN3);
#endif
if (rep0 == UINT32_MAX) {
// End of payload marker was
// found. It must not be
// present if uncompressed
// size is known.
if (coder->uncompressed_size
!= LZMA_VLI_UNKNOWN) {
ret = LZMA_DATA_ERROR;
goto out;
}
case SEQ_EOPM:
// LZMA1 stream with
// end-of-payload marker.
rc_normalize(SEQ_EOPM);
ret = LZMA_STREAM_END;
goto out;
}
}
}
// Validate the distance we just decoded.
if (unlikely(!dict_is_distance_valid(&dict, rep0))) {
ret = LZMA_DATA_ERROR;
goto out;
}
} else {
rc_update_1(coder->is_rep[state]);
// Repeated match
//
// The match distance is a value that we have had
// earlier. The latest four match distances are
// available as rep0, rep1, rep2 and rep3. We will
// now decode which of them is the new distance.
//
// There cannot be a match if we haven't produced
// any output, so check that first.
if (unlikely(!dict_is_distance_valid(&dict, 0))) {
ret = LZMA_DATA_ERROR;
goto out;
}
case SEQ_IS_REP0:
rc_if_0(coder->is_rep0[state], SEQ_IS_REP0) {
rc_update_0(coder->is_rep0[state]);
// The distance is rep0.
case SEQ_IS_REP0_LONG:
rc_if_0(coder->is_rep0_long[state][pos_state],
SEQ_IS_REP0_LONG) {
rc_update_0(coder->is_rep0_long[
state][pos_state]);
update_short_rep(state);
case SEQ_SHORTREP:
if (unlikely(dict_put(&dict, dict_get(
&dict, rep0)))) {
coder->sequence = SEQ_SHORTREP;
goto out;
}
continue;
}
// Repeating more than one byte at
// distance of rep0.
rc_update_1(coder->is_rep0_long[
state][pos_state]);
} else {
rc_update_1(coder->is_rep0[state]);
case SEQ_IS_REP1:
// The distance is rep1, rep2 or rep3. Once
// we find out which one of these three, it
// is stored to rep0 and rep1, rep2 and rep3
// are updated accordingly.
rc_if_0(coder->is_rep1[state], SEQ_IS_REP1) {
rc_update_0(coder->is_rep1[state]);
const uint32_t distance = rep1;
rep1 = rep0;
rep0 = distance;
} else {
rc_update_1(coder->is_rep1[state]);
case SEQ_IS_REP2:
rc_if_0(coder->is_rep2[state],
SEQ_IS_REP2) {
rc_update_0(coder->is_rep2[
state]);
const uint32_t distance = rep2;
rep2 = rep1;
rep1 = rep0;
rep0 = distance;
} else {
rc_update_1(coder->is_rep2[
state]);
const uint32_t distance = rep3;
rep3 = rep2;
rep2 = rep1;
rep1 = rep0;
rep0 = distance;
}
}
}
update_long_rep(state);
// Decode the length of the repeated match.
len_decode(len, coder->rep_len_decoder,
pos_state, SEQ_REP_LEN);
}
/////////////////////////////////
// Repeat from history buffer. //
/////////////////////////////////
// The length is always between these limits. There is no way
// to trigger the algorithm to set len outside this range.
assert(len >= MATCH_LEN_MIN);
assert(len <= MATCH_LEN_MAX);
case SEQ_COPY:
// Repeat len bytes from distance of rep0.
if (unlikely(dict_repeat(&dict, rep0, &len))) {
coder->sequence = SEQ_COPY;
goto out;
}
}
rc_normalize(SEQ_NORMALIZE);
coder->sequence = SEQ_IS_MATCH;
out:
// Save state
// NOTE: Must not copy dict.limit.
dictptr->pos = dict.pos;
dictptr->full = dict.full;
rc_from_local(coder->rc, *in_pos);
coder->state = state;
coder->rep0 = rep0;
coder->rep1 = rep1;
coder->rep2 = rep2;
coder->rep3 = rep3;
coder->probs = probs;
coder->symbol = symbol;
coder->limit = limit;
coder->offset = offset;
coder->len = len;
// Update the remaining amount of uncompressed data if uncompressed
// size was known.
if (coder->uncompressed_size != LZMA_VLI_UNKNOWN) {
coder->uncompressed_size -= dict.pos - dict_start;
// Since there cannot be end of payload marker if the
// uncompressed size was known, we check here if we
// finished decoding.
if (coder->uncompressed_size == 0 && ret == LZMA_OK
&& coder->sequence != SEQ_NORMALIZE)
ret = coder->sequence == SEQ_IS_MATCH
? LZMA_STREAM_END : LZMA_DATA_ERROR;
}
// We can do an additional check in the range decoder to catch some
// corrupted files.
if (ret == LZMA_STREAM_END) {
if (!rc_is_finished(coder->rc))
ret = LZMA_DATA_ERROR;
// Reset the range decoder so that it is ready to reinitialize
// for a new LZMA2 chunk.
rc_reset(coder->rc);
}
return ret;
}
static void
lzma_decoder_uncompressed(void *coder_ptr, lzma_vli uncompressed_size)
{
lzma_lzma1_decoder *coder = coder_ptr;
coder->uncompressed_size = uncompressed_size;
}
static void
lzma_decoder_reset(void *coder_ptr, const void *opt)
{
lzma_lzma1_decoder *coder = coder_ptr;
const lzma_options_lzma *options = opt;
// NOTE: We assume that lc/lp/pb are valid since they were
// successfully decoded with lzma_lzma_decode_properties().
// Calculate pos_mask. We don't need pos_bits as is for anything.
coder->pos_mask = (1U << options->pb) - 1;
// Initialize the literal decoder.
literal_init(coder->literal, options->lc, options->lp);
coder->literal_context_bits = options->lc;
coder->literal_pos_mask = (1U << options->lp) - 1;
// State
coder->state = STATE_LIT_LIT;
coder->rep0 = 0;
coder->rep1 = 0;
coder->rep2 = 0;
coder->rep3 = 0;
coder->pos_mask = (1U << options->pb) - 1;
// Range decoder
rc_reset(coder->rc);
// Bit and bittree decoders
for (uint32_t i = 0; i < STATES; ++i) {
for (uint32_t j = 0; j <= coder->pos_mask; ++j) {
bit_reset(coder->is_match[i][j]);
bit_reset(coder->is_rep0_long[i][j]);
}
bit_reset(coder->is_rep[i]);
bit_reset(coder->is_rep0[i]);
bit_reset(coder->is_rep1[i]);
bit_reset(coder->is_rep2[i]);
}
for (uint32_t i = 0; i < DIST_STATES; ++i)
bittree_reset(coder->dist_slot[i], DIST_SLOT_BITS);
for (uint32_t i = 0; i < FULL_DISTANCES - DIST_MODEL_END; ++i)
bit_reset(coder->pos_special[i]);
bittree_reset(coder->pos_align, ALIGN_BITS);
// Len decoders (also bit/bittree)
const uint32_t num_pos_states = 1U << options->pb;
bit_reset(coder->match_len_decoder.choice);
bit_reset(coder->match_len_decoder.choice2);
bit_reset(coder->rep_len_decoder.choice);
bit_reset(coder->rep_len_decoder.choice2);
for (uint32_t pos_state = 0; pos_state < num_pos_states; ++pos_state) {
bittree_reset(coder->match_len_decoder.low[pos_state],
LEN_LOW_BITS);
bittree_reset(coder->match_len_decoder.mid[pos_state],
LEN_MID_BITS);
bittree_reset(coder->rep_len_decoder.low[pos_state],
LEN_LOW_BITS);
bittree_reset(coder->rep_len_decoder.mid[pos_state],
LEN_MID_BITS);
}
bittree_reset(coder->match_len_decoder.high, LEN_HIGH_BITS);
bittree_reset(coder->rep_len_decoder.high, LEN_HIGH_BITS);
coder->sequence = SEQ_IS_MATCH;
coder->probs = NULL;
coder->symbol = 0;
coder->limit = 0;
coder->offset = 0;
coder->len = 0;
return;
}
extern lzma_ret
lzma_lzma_decoder_create(lzma_lz_decoder *lz, const lzma_allocator *allocator,
const void *opt, lzma_lz_options *lz_options)
{
if (lz->coder == NULL) {
lz->coder = lzma_alloc(sizeof(lzma_lzma1_decoder), allocator);
if (lz->coder == NULL)
return LZMA_MEM_ERROR;
lz->code = &lzma_decode;
lz->reset = &lzma_decoder_reset;
lz->set_uncompressed = &lzma_decoder_uncompressed;
}
// All dictionary sizes are OK here. LZ decoder will take care of
// the special cases.
const lzma_options_lzma *options = opt;
lz_options->dict_size = options->dict_size;
lz_options->preset_dict = options->preset_dict;
lz_options->preset_dict_size = options->preset_dict_size;
return LZMA_OK;
}
/// Allocate and initialize LZMA decoder. This is used only via LZ
/// initialization (lzma_lzma_decoder_init() passes function pointer to
/// the LZ initialization).
static lzma_ret
lzma_decoder_init(lzma_lz_decoder *lz, const lzma_allocator *allocator,
const void *options, lzma_lz_options *lz_options)
{
if (!is_lclppb_valid(options))
return LZMA_PROG_ERROR;
return_if_error(lzma_lzma_decoder_create(
lz, allocator, options, lz_options));
lzma_decoder_reset(lz->coder, options);
lzma_decoder_uncompressed(lz->coder, LZMA_VLI_UNKNOWN);
return LZMA_OK;
}
extern lzma_ret
lzma_lzma_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
const lzma_filter_info *filters)
{
// LZMA can only be the last filter in the chain. This is enforced
// by the raw_decoder initialization.
assert(filters[1].init == NULL);
return lzma_lz_decoder_init(next, allocator, filters,
&lzma_decoder_init);
}
extern bool
lzma_lzma_lclppb_decode(lzma_options_lzma *options, uint8_t byte)