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debian: Prepare for upload
[xz/debian.git] / src / liblzma / lzma / lzma_decoder.c
blobd0f29b763a3c384a6760d7f8a5d1133e8d3fd8fe
1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file lzma_decoder.c
4 /// \brief LZMA decoder
5 ///
6 // Authors: Igor Pavlov
7 // Lasse Collin
8 //
9 // This file has been put into the public domain.
10 // You can do whatever you want with this file.
11 //
12 ///////////////////////////////////////////////////////////////////////////////
13
14 #include "lz_decoder.h"
15 #include "lzma_common.h"
16 #include "lzma_decoder.h"
17 #include "range_decoder.h"
18
19 // The macros unroll loops with switch statements.
20 // Silence warnings about missing fall-through comments.
21 #if TUKLIB_GNUC_REQ(7, 0)
22 # pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
23 #endif
24
25
26 #ifdef HAVE_SMALL
27
28 // Macros for (somewhat) size-optimized code.
29 #define seq_4(seq) seq
30
31 #define seq_6(seq) seq
32
33 #define seq_8(seq) seq
34
35 #define seq_len(seq) \
36 seq ## _CHOICE, \
37 seq ## _CHOICE2, \
38 seq ## _BITTREE
39
40 #define len_decode(target, ld, pos_state, seq) \
41 do { \
42 case seq ## _CHOICE: \
43 rc_if_0(ld.choice, seq ## _CHOICE) { \
44 rc_update_0(ld.choice); \
45 probs = ld.low[pos_state];\
46 limit = LEN_LOW_SYMBOLS; \
47 target = MATCH_LEN_MIN; \
48 } else { \
49 rc_update_1(ld.choice); \
50 case seq ## _CHOICE2: \
51 rc_if_0(ld.choice2, seq ## _CHOICE2) { \
52 rc_update_0(ld.choice2); \
53 probs = ld.mid[pos_state]; \
54 limit = LEN_MID_SYMBOLS; \
55 target = MATCH_LEN_MIN + LEN_LOW_SYMBOLS; \
56 } else { \
57 rc_update_1(ld.choice2); \
58 probs = ld.high; \
59 limit = LEN_HIGH_SYMBOLS; \
60 target = MATCH_LEN_MIN + LEN_LOW_SYMBOLS \
61 + LEN_MID_SYMBOLS; \
62 } \
63 } \
64 symbol = 1; \
65 case seq ## _BITTREE: \
66 do { \
67 rc_bit(probs[symbol], , , seq ## _BITTREE); \
68 } while (symbol < limit); \
69 target += symbol - limit; \
70 } while (0)
71
72 #else // HAVE_SMALL
73
74 // Unrolled versions
75 #define seq_4(seq) \
76 seq ## 0, \
77 seq ## 1, \
78 seq ## 2, \
79 seq ## 3
80
81 #define seq_6(seq) \
82 seq ## 0, \
83 seq ## 1, \
84 seq ## 2, \
85 seq ## 3, \
86 seq ## 4, \
87 seq ## 5
88
89 #define seq_8(seq) \
90 seq ## 0, \
91 seq ## 1, \
92 seq ## 2, \
93 seq ## 3, \
94 seq ## 4, \
95 seq ## 5, \
96 seq ## 6, \
97 seq ## 7
98
99 #define seq_len(seq) \
100 seq ## _CHOICE, \
101 seq ## _LOW0, \
102 seq ## _LOW1, \
103 seq ## _LOW2, \
104 seq ## _CHOICE2, \
105 seq ## _MID0, \
106 seq ## _MID1, \
107 seq ## _MID2, \
108 seq ## _HIGH0, \
109 seq ## _HIGH1, \
110 seq ## _HIGH2, \
111 seq ## _HIGH3, \
112 seq ## _HIGH4, \
113 seq ## _HIGH5, \
114 seq ## _HIGH6, \
115 seq ## _HIGH7
116
117 #define len_decode(target, ld, pos_state, seq) \
118 do { \
119 symbol = 1; \
120 case seq ## _CHOICE: \
121 rc_if_0(ld.choice, seq ## _CHOICE) { \
122 rc_update_0(ld.choice); \
123 rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW0); \
124 rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW1); \
125 rc_bit_case(ld.low[pos_state][symbol], , , seq ## _LOW2); \
126 target = symbol - LEN_LOW_SYMBOLS + MATCH_LEN_MIN; \
127 } else { \
128 rc_update_1(ld.choice); \
129 case seq ## _CHOICE2: \
130 rc_if_0(ld.choice2, seq ## _CHOICE2) { \
131 rc_update_0(ld.choice2); \
132 rc_bit_case(ld.mid[pos_state][symbol], , , \
133 seq ## _MID0); \
134 rc_bit_case(ld.mid[pos_state][symbol], , , \
135 seq ## _MID1); \
136 rc_bit_case(ld.mid[pos_state][symbol], , , \
137 seq ## _MID2); \
138 target = symbol - LEN_MID_SYMBOLS \
139 + MATCH_LEN_MIN + LEN_LOW_SYMBOLS; \
140 } else { \
141 rc_update_1(ld.choice2); \
142 rc_bit_case(ld.high[symbol], , , seq ## _HIGH0); \
143 rc_bit_case(ld.high[symbol], , , seq ## _HIGH1); \
144 rc_bit_case(ld.high[symbol], , , seq ## _HIGH2); \
145 rc_bit_case(ld.high[symbol], , , seq ## _HIGH3); \
146 rc_bit_case(ld.high[symbol], , , seq ## _HIGH4); \
147 rc_bit_case(ld.high[symbol], , , seq ## _HIGH5); \
148 rc_bit_case(ld.high[symbol], , , seq ## _HIGH6); \
149 rc_bit_case(ld.high[symbol], , , seq ## _HIGH7); \
150 target = symbol - LEN_HIGH_SYMBOLS \
151 + MATCH_LEN_MIN \
152 + LEN_LOW_SYMBOLS + LEN_MID_SYMBOLS; \
153 } \
154 } \
155 } while (0)
156
157 #endif // HAVE_SMALL
158
159
160 /// Length decoder probabilities; see comments in lzma_common.h.
161 typedef struct {
162 probability choice;
163 probability choice2;
164 probability low[POS_STATES_MAX][LEN_LOW_SYMBOLS];
165 probability mid[POS_STATES_MAX][LEN_MID_SYMBOLS];
166 probability high[LEN_HIGH_SYMBOLS];
167 } lzma_length_decoder;
168
169
170 typedef struct {
171 ///////////////////
172 // Probabilities //
173 ///////////////////
174
175 /// Literals; see comments in lzma_common.h.
176 probability literal[LITERAL_CODERS_MAX][LITERAL_CODER_SIZE];
177
178 /// If 1, it's a match. Otherwise it's a single 8-bit literal.
179 probability is_match[STATES][POS_STATES_MAX];
180
181 /// If 1, it's a repeated match. The distance is one of rep0 .. rep3.
182 probability is_rep[STATES];
183
184 /// If 0, distance of a repeated match is rep0.
185 /// Otherwise check is_rep1.
186 probability is_rep0[STATES];
187
188 /// If 0, distance of a repeated match is rep1.
189 /// Otherwise check is_rep2.
190 probability is_rep1[STATES];
191
192 /// If 0, distance of a repeated match is rep2. Otherwise it is rep3.
193 probability is_rep2[STATES];
194
195 /// If 1, the repeated match has length of one byte. Otherwise
196 /// the length is decoded from rep_len_decoder.
197 probability is_rep0_long[STATES][POS_STATES_MAX];
198
199 /// Probability tree for the highest two bits of the match distance.
200 /// There is a separate probability tree for match lengths of
201 /// 2 (i.e. MATCH_LEN_MIN), 3, 4, and [5, 273].
202 probability dist_slot[DIST_STATES][DIST_SLOTS];
203
204 /// Probability trees for additional bits for match distance when the
205 /// distance is in the range [4, 127].
206 probability pos_special[FULL_DISTANCES - DIST_MODEL_END];
207
208 /// Probability tree for the lowest four bits of a match distance
209 /// that is equal to or greater than 128.
210 probability pos_align[ALIGN_SIZE];
211
212 /// Length of a normal match
213 lzma_length_decoder match_len_decoder;
214
215 /// Length of a repeated match
216 lzma_length_decoder rep_len_decoder;
217
218 ///////////////////
219 // Decoder state //
220 ///////////////////
221
222 // Range coder
223 lzma_range_decoder rc;
224
225 // Types of the most recently seen LZMA symbols
226 lzma_lzma_state state;
227
228 uint32_t rep0; ///< Distance of the latest match
229 uint32_t rep1; ///< Distance of second latest match
230 uint32_t rep2; ///< Distance of third latest match
231 uint32_t rep3; ///< Distance of fourth latest match
232
233 uint32_t pos_mask; // (1U << pb) - 1
234 uint32_t literal_context_bits;
235 uint32_t literal_pos_mask;
236
237 /// Uncompressed size as bytes, or LZMA_VLI_UNKNOWN if end of
238 /// payload marker is expected.
239 lzma_vli uncompressed_size;
240
241 ////////////////////////////////
242 // State of incomplete symbol //
243 ////////////////////////////////
244
245 /// Position where to continue the decoder loop
246 enum {
247 SEQ_NORMALIZE,
248 SEQ_IS_MATCH,
249 seq_8(SEQ_LITERAL),
250 seq_8(SEQ_LITERAL_MATCHED),
251 SEQ_LITERAL_WRITE,
252 SEQ_IS_REP,
253 seq_len(SEQ_MATCH_LEN),
254 seq_6(SEQ_DIST_SLOT),
255 SEQ_DIST_MODEL,
256 SEQ_DIRECT,
257 seq_4(SEQ_ALIGN),
258 SEQ_EOPM,
259 SEQ_IS_REP0,
260 SEQ_SHORTREP,
261 SEQ_IS_REP0_LONG,
262 SEQ_IS_REP1,
263 SEQ_IS_REP2,
264 seq_len(SEQ_REP_LEN),
265 SEQ_COPY,
266 } sequence;
267
268 /// Base of the current probability tree
269 probability *probs;
270
271 /// Symbol being decoded. This is also used as an index variable in
272 /// bittree decoders: probs[symbol]
273 uint32_t symbol;
274
275 /// Used as a loop termination condition on bittree decoders and
276 /// direct bits decoder.
277 uint32_t limit;
278
279 /// Matched literal decoder: 0x100 or 0 to help avoiding branches.
280 /// Bittree reverse decoders: Offset of the next bit: 1 << offset
281 uint32_t offset;
282
283 /// If decoding a literal: match byte.
284 /// If decoding a match: length of the match.
285 uint32_t len;
286 } lzma_lzma1_decoder;
287
288
289 static lzma_ret
290 lzma_decode(void *coder_ptr, lzma_dict *restrict dictptr,
291 const uint8_t *restrict in,
292 size_t *restrict in_pos, size_t in_size)
293 {
294 lzma_lzma1_decoder *restrict coder = coder_ptr;
295
296 ////////////////////
297 // Initialization //
298 ////////////////////
299
300 {
301 const lzma_ret ret = rc_read_init(
302 &coder->rc, in, in_pos, in_size);
303 if (ret != LZMA_STREAM_END)
304 return ret;
305 }
306
307 ///////////////
308 // Variables //
309 ///////////////
310
311 // Making local copies of often-used variables improves both
312 // speed and readability.
313
314 lzma_dict dict = *dictptr;
315
316 const size_t dict_start = dict.pos;
317
318 // Range decoder
319 rc_to_local(coder->rc, *in_pos);
320
321 // State
322 uint32_t state = coder->state;
323 uint32_t rep0 = coder->rep0;
324 uint32_t rep1 = coder->rep1;
325 uint32_t rep2 = coder->rep2;
326 uint32_t rep3 = coder->rep3;
327
328 const uint32_t pos_mask = coder->pos_mask;
329
330 // These variables are actually needed only if we last time ran
331 // out of input in the middle of the decoder loop.
332 probability *probs = coder->probs;
333 uint32_t symbol = coder->symbol;
334 uint32_t limit = coder->limit;
335 uint32_t offset = coder->offset;
336 uint32_t len = coder->len;
337
338 const uint32_t literal_pos_mask = coder->literal_pos_mask;
339 const uint32_t literal_context_bits = coder->literal_context_bits;
340
341 // Temporary variables
342 uint32_t pos_state = dict.pos & pos_mask;
343
344 lzma_ret ret = LZMA_OK;
345
346 // If uncompressed size is known, there must be no end of payload
347 // marker.
348 const bool no_eopm = coder->uncompressed_size
349 != LZMA_VLI_UNKNOWN;
350 if (no_eopm && coder->uncompressed_size < dict.limit - dict.pos)
351 dict.limit = dict.pos + (size_t)(coder->uncompressed_size);
352
353 // The main decoder loop. The "switch" is used to restart the decoder at
354 // correct location. Once restarted, the "switch" is no longer used.
355 switch (coder->sequence)
356 while (true) {
357 // Calculate new pos_state. This is skipped on the first loop
358 // since we already calculated it when setting up the local
359 // variables.
360 pos_state = dict.pos & pos_mask;
361
362 case SEQ_NORMALIZE:
363 case SEQ_IS_MATCH:
364 if (unlikely(no_eopm && dict.pos == dict.limit))
365 break;
366
367 rc_if_0(coder->is_match[state][pos_state], SEQ_IS_MATCH) {
368 rc_update_0(coder->is_match[state][pos_state]);
369
370 // It's a literal i.e. a single 8-bit byte.
371
372 probs = literal_subcoder(coder->literal,
373 literal_context_bits, literal_pos_mask,
374 dict.pos, dict_get(&dict, 0));
375 symbol = 1;
376
377 if (is_literal_state(state)) {
378 // Decode literal without match byte.
379 #ifdef HAVE_SMALL
380 case SEQ_LITERAL:
381 do {
382 rc_bit(probs[symbol], , , SEQ_LITERAL);
383 } while (symbol < (1 << 8));
384 #else
385 rc_bit_case(probs[symbol], , , SEQ_LITERAL0);
386 rc_bit_case(probs[symbol], , , SEQ_LITERAL1);
387 rc_bit_case(probs[symbol], , , SEQ_LITERAL2);
388 rc_bit_case(probs[symbol], , , SEQ_LITERAL3);
389 rc_bit_case(probs[symbol], , , SEQ_LITERAL4);
390 rc_bit_case(probs[symbol], , , SEQ_LITERAL5);
391 rc_bit_case(probs[symbol], , , SEQ_LITERAL6);
392 rc_bit_case(probs[symbol], , , SEQ_LITERAL7);
393 #endif
394 } else {
395 // Decode literal with match byte.
396 //
397 // We store the byte we compare against
398 // ("match byte") to "len" to minimize the
399 // number of variables we need to store
400 // between decoder calls.
401 len = dict_get(&dict, rep0) << 1;
402
403 // The usage of "offset" allows omitting some
404 // branches, which should give tiny speed
405 // improvement on some CPUs. "offset" gets
406 // set to zero if match_bit didn't match.
407 offset = 0x100;
408
409 #ifdef HAVE_SMALL
410 case SEQ_LITERAL_MATCHED:
411 do {
412 const uint32_t match_bit
413 = len & offset;
414 const uint32_t subcoder_index
415 = offset + match_bit
416 + symbol;
417
418 rc_bit(probs[subcoder_index],
419 offset &= ~match_bit,
420 offset &= match_bit,
421 SEQ_LITERAL_MATCHED);
422
423 // It seems to be faster to do this
424 // here instead of putting it to the
425 // beginning of the loop and then
426 // putting the "case" in the middle
427 // of the loop.
428 len <<= 1;
429
430 } while (symbol < (1 << 8));
431 #else
432 // Unroll the loop.
433 uint32_t match_bit;
434 uint32_t subcoder_index;
435
436 # define d(seq) \
437 case seq: \
438 match_bit = len & offset; \
439 subcoder_index = offset + match_bit + symbol; \
440 rc_bit(probs[subcoder_index], \
441 offset &= ~match_bit, \
442 offset &= match_bit, \
443 seq)
444
445 d(SEQ_LITERAL_MATCHED0);
446 len <<= 1;
447 d(SEQ_LITERAL_MATCHED1);
448 len <<= 1;
449 d(SEQ_LITERAL_MATCHED2);
450 len <<= 1;
451 d(SEQ_LITERAL_MATCHED3);
452 len <<= 1;
453 d(SEQ_LITERAL_MATCHED4);
454 len <<= 1;
455 d(SEQ_LITERAL_MATCHED5);
456 len <<= 1;
457 d(SEQ_LITERAL_MATCHED6);
458 len <<= 1;
459 d(SEQ_LITERAL_MATCHED7);
460 # undef d
461 #endif
462 }
463
464 //update_literal(state);
465 // Use a lookup table to update to literal state,
466 // since compared to other state updates, this would
467 // need two branches.
468 static const lzma_lzma_state next_state[] = {
469 STATE_LIT_LIT,
470 STATE_LIT_LIT,
471 STATE_LIT_LIT,
472 STATE_LIT_LIT,
473 STATE_MATCH_LIT_LIT,
474 STATE_REP_LIT_LIT,
475 STATE_SHORTREP_LIT_LIT,
476 STATE_MATCH_LIT,
477 STATE_REP_LIT,
478 STATE_SHORTREP_LIT,
479 STATE_MATCH_LIT,
480 STATE_REP_LIT
481 };
482 state = next_state[state];
483
484 case SEQ_LITERAL_WRITE:
485 if (unlikely(dict_put(&dict, symbol))) {
486 coder->sequence = SEQ_LITERAL_WRITE;
487 goto out;
488 }
489
490 continue;
491 }
492
493 // Instead of a new byte we are going to get a byte range
494 // (distance and length) which will be repeated from our
495 // output history.
496
497 rc_update_1(coder->is_match[state][pos_state]);
498
499 case SEQ_IS_REP:
500 rc_if_0(coder->is_rep[state], SEQ_IS_REP) {
501 // Not a repeated match
502 rc_update_0(coder->is_rep[state]);
503 update_match(state);
504
505 // The latest three match distances are kept in
506 // memory in case there are repeated matches.
507 rep3 = rep2;
508 rep2 = rep1;
509 rep1 = rep0;
510
511 // Decode the length of the match.
512 len_decode(len, coder->match_len_decoder,
513 pos_state, SEQ_MATCH_LEN);
514
515 // Prepare to decode the highest two bits of the
516 // match distance.
517 probs = coder->dist_slot[get_dist_state(len)];
518 symbol = 1;
519
520 #ifdef HAVE_SMALL
521 case SEQ_DIST_SLOT:
522 do {
523 rc_bit(probs[symbol], , , SEQ_DIST_SLOT);
524 } while (symbol < DIST_SLOTS);
525 #else
526 rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT0);
527 rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT1);
528 rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT2);
529 rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT3);
530 rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT4);
531 rc_bit_case(probs[symbol], , , SEQ_DIST_SLOT5);
532 #endif
533 // Get rid of the highest bit that was needed for
534 // indexing of the probability array.
535 symbol -= DIST_SLOTS;
536 assert(symbol <= 63);
537
538 if (symbol < DIST_MODEL_START) {
539 // Match distances [0, 3] have only two bits.
540 rep0 = symbol;
541 } else {
542 // Decode the lowest [1, 29] bits of
543 // the match distance.
544 limit = (symbol >> 1) - 1;
545 assert(limit >= 1 && limit <= 30);
546 rep0 = 2 + (symbol & 1);
547
548 if (symbol < DIST_MODEL_END) {
549 // Prepare to decode the low bits for
550 // a distance of [4, 127].
551 assert(limit <= 5);
552 rep0 <<= limit;
553 assert(rep0 <= 96);
554 // -1 is fine, because we start
555 // decoding at probs[1], not probs[0].
556 // NOTE: This violates the C standard,
557 // since we are doing pointer
558 // arithmetic past the beginning of
559 // the array.
560 assert((int32_t)(rep0 - symbol - 1)
561 >= -1);
562 assert((int32_t)(rep0 - symbol - 1)
563 <= 82);
564 probs = coder->pos_special + rep0
565 - symbol - 1;
566 symbol = 1;
567 offset = 0;
568 case SEQ_DIST_MODEL:
569 #ifdef HAVE_SMALL
570 do {
571 rc_bit(probs[symbol], ,
572 rep0 += 1 << offset,
573 SEQ_DIST_MODEL);
574 } while (++offset < limit);
575 #else
576 switch (limit) {
577 case 5:
578 assert(offset == 0);
579 rc_bit(probs[symbol], ,
580 rep0 += 1,
581 SEQ_DIST_MODEL);
582 ++offset;
583 --limit;
584 case 4:
585 rc_bit(probs[symbol], ,
586 rep0 += 1 << offset,
587 SEQ_DIST_MODEL);
588 ++offset;
589 --limit;
590 case 3:
591 rc_bit(probs[symbol], ,
592 rep0 += 1 << offset,
593 SEQ_DIST_MODEL);
594 ++offset;
595 --limit;
596 case 2:
597 rc_bit(probs[symbol], ,
598 rep0 += 1 << offset,
599 SEQ_DIST_MODEL);
600 ++offset;
601 --limit;
602 case 1:
603 // We need "symbol" only for
604 // indexing the probability
605 // array, thus we can use
606 // rc_bit_last() here to omit
607 // the unneeded updating of
608 // "symbol".
609 rc_bit_last(probs[symbol], ,
610 rep0 += 1 << offset,
611 SEQ_DIST_MODEL);
612 }
613 #endif
614 } else {
615 // The distance is >= 128. Decode the
616 // lower bits without probabilities
617 // except the lowest four bits.
618 assert(symbol >= 14);
619 assert(limit >= 6);
620 limit -= ALIGN_BITS;
621 assert(limit >= 2);
622 case SEQ_DIRECT:
623 // Not worth manual unrolling
624 do {
625 rc_direct(rep0, SEQ_DIRECT);
626 } while (--limit > 0);
627
628 // Decode the lowest four bits using
629 // probabilities.
630 rep0 <<= ALIGN_BITS;
631 symbol = 1;
632 #ifdef HAVE_SMALL
633 offset = 0;
634 case SEQ_ALIGN:
635 do {
636 rc_bit(coder->pos_align[
637 symbol], ,
638 rep0 += 1 << offset,
639 SEQ_ALIGN);
640 } while (++offset < ALIGN_BITS);
641 #else
642 case SEQ_ALIGN0:
643 rc_bit(coder->pos_align[symbol], ,
644 rep0 += 1, SEQ_ALIGN0);
645 case SEQ_ALIGN1:
646 rc_bit(coder->pos_align[symbol], ,
647 rep0 += 2, SEQ_ALIGN1);
648 case SEQ_ALIGN2:
649 rc_bit(coder->pos_align[symbol], ,
650 rep0 += 4, SEQ_ALIGN2);
651 case SEQ_ALIGN3:
652 // Like in SEQ_DIST_MODEL, we don't
653 // need "symbol" for anything else
654 // than indexing the probability array.
655 rc_bit_last(coder->pos_align[symbol], ,
656 rep0 += 8, SEQ_ALIGN3);
657 #endif
658
659 if (rep0 == UINT32_MAX) {
660 // End of payload marker was
661 // found. It must not be
662 // present if uncompressed
663 // size is known.
664 if (coder->uncompressed_size
665 != LZMA_VLI_UNKNOWN) {
666 ret = LZMA_DATA_ERROR;
667 goto out;
668 }
669
670 case SEQ_EOPM:
671 // LZMA1 stream with
672 // end-of-payload marker.
673 rc_normalize(SEQ_EOPM);
674 ret = LZMA_STREAM_END;
675 goto out;
676 }
677 }
678 }
679
680 // Validate the distance we just decoded.
681 if (unlikely(!dict_is_distance_valid(&dict, rep0))) {
682 ret = LZMA_DATA_ERROR;
683 goto out;
684 }
685
686 } else {
687 rc_update_1(coder->is_rep[state]);
688
689 // Repeated match
690 //
691 // The match distance is a value that we have had
692 // earlier. The latest four match distances are
693 // available as rep0, rep1, rep2 and rep3. We will
694 // now decode which of them is the new distance.
695 //
696 // There cannot be a match if we haven't produced
697 // any output, so check that first.
698 if (unlikely(!dict_is_distance_valid(&dict, 0))) {
699 ret = LZMA_DATA_ERROR;
700 goto out;
701 }
702
703 case SEQ_IS_REP0:
704 rc_if_0(coder->is_rep0[state], SEQ_IS_REP0) {
705 rc_update_0(coder->is_rep0[state]);
706 // The distance is rep0.
707
708 case SEQ_IS_REP0_LONG:
709 rc_if_0(coder->is_rep0_long[state][pos_state],
710 SEQ_IS_REP0_LONG) {
711 rc_update_0(coder->is_rep0_long[
712 state][pos_state]);
713
714 update_short_rep(state);
715
716 case SEQ_SHORTREP:
717 if (unlikely(dict_put(&dict, dict_get(
718 &dict, rep0)))) {
719 coder->sequence = SEQ_SHORTREP;
720 goto out;
721 }
722
723 continue;
724 }
725
726 // Repeating more than one byte at
727 // distance of rep0.
728 rc_update_1(coder->is_rep0_long[
729 state][pos_state]);
730
731 } else {
732 rc_update_1(coder->is_rep0[state]);
733
734 case SEQ_IS_REP1:
735 // The distance is rep1, rep2 or rep3. Once
736 // we find out which one of these three, it
737 // is stored to rep0 and rep1, rep2 and rep3
738 // are updated accordingly.
739 rc_if_0(coder->is_rep1[state], SEQ_IS_REP1) {
740 rc_update_0(coder->is_rep1[state]);
741
742 const uint32_t distance = rep1;
743 rep1 = rep0;
744 rep0 = distance;
745
746 } else {
747 rc_update_1(coder->is_rep1[state]);
748 case SEQ_IS_REP2:
749 rc_if_0(coder->is_rep2[state],
750 SEQ_IS_REP2) {
751 rc_update_0(coder->is_rep2[
752 state]);
753
754 const uint32_t distance = rep2;
755 rep2 = rep1;
756 rep1 = rep0;
757 rep0 = distance;
758
759 } else {
760 rc_update_1(coder->is_rep2[
761 state]);
762
763 const uint32_t distance = rep3;
764 rep3 = rep2;
765 rep2 = rep1;
766 rep1 = rep0;
767 rep0 = distance;
768 }
769 }
770 }
771
772 update_long_rep(state);
773
774 // Decode the length of the repeated match.
775 len_decode(len, coder->rep_len_decoder,
776 pos_state, SEQ_REP_LEN);
777 }
778
779 /////////////////////////////////
780 // Repeat from history buffer. //
781 /////////////////////////////////
782
783 // The length is always between these limits. There is no way
784 // to trigger the algorithm to set len outside this range.
785 assert(len >= MATCH_LEN_MIN);
786 assert(len <= MATCH_LEN_MAX);
787
788 case SEQ_COPY:
789 // Repeat len bytes from distance of rep0.
790 if (unlikely(dict_repeat(&dict, rep0, &len))) {
791 coder->sequence = SEQ_COPY;
792 goto out;
793 }
794 }
795
796 rc_normalize(SEQ_NORMALIZE);
797 coder->sequence = SEQ_IS_MATCH;
798
799 out:
800 // Save state
801
802 // NOTE: Must not copy dict.limit.
803 dictptr->pos = dict.pos;
804 dictptr->full = dict.full;
805
806 rc_from_local(coder->rc, *in_pos);
807
808 coder->state = state;
809 coder->rep0 = rep0;
810 coder->rep1 = rep1;
811 coder->rep2 = rep2;
812 coder->rep3 = rep3;
813
814 coder->probs = probs;
815 coder->symbol = symbol;
816 coder->limit = limit;
817 coder->offset = offset;
818 coder->len = len;
819
820 // Update the remaining amount of uncompressed data if uncompressed
821 // size was known.
822 if (coder->uncompressed_size != LZMA_VLI_UNKNOWN) {
823 coder->uncompressed_size -= dict.pos - dict_start;
824
825 // Since there cannot be end of payload marker if the
826 // uncompressed size was known, we check here if we
827 // finished decoding.
828 if (coder->uncompressed_size == 0 && ret == LZMA_OK
829 && coder->sequence != SEQ_NORMALIZE)
830 ret = coder->sequence == SEQ_IS_MATCH
831 ? LZMA_STREAM_END : LZMA_DATA_ERROR;
832 }
833
834 // We can do an additional check in the range decoder to catch some
835 // corrupted files.
836 if (ret == LZMA_STREAM_END) {
837 if (!rc_is_finished(coder->rc))
838 ret = LZMA_DATA_ERROR;
839
840 // Reset the range decoder so that it is ready to reinitialize
841 // for a new LZMA2 chunk.
842 rc_reset(coder->rc);
843 }
844
845 return ret;
846 }
847
848
849
850 static void
851 lzma_decoder_uncompressed(void *coder_ptr, lzma_vli uncompressed_size)
852 {
853 lzma_lzma1_decoder *coder = coder_ptr;
854 coder->uncompressed_size = uncompressed_size;
855 }
856
857
858 static void
859 lzma_decoder_reset(void *coder_ptr, const void *opt)
860 {
861 lzma_lzma1_decoder *coder = coder_ptr;
862 const lzma_options_lzma *options = opt;
863
864 // NOTE: We assume that lc/lp/pb are valid since they were
865 // successfully decoded with lzma_lzma_decode_properties().
866
867 // Calculate pos_mask. We don't need pos_bits as is for anything.
868 coder->pos_mask = (1U << options->pb) - 1;
869
870 // Initialize the literal decoder.
871 literal_init(coder->literal, options->lc, options->lp);
872
873 coder->literal_context_bits = options->lc;
874 coder->literal_pos_mask = (1U << options->lp) - 1;
875
876 // State
877 coder->state = STATE_LIT_LIT;
878 coder->rep0 = 0;
879 coder->rep1 = 0;
880 coder->rep2 = 0;
881 coder->rep3 = 0;
882 coder->pos_mask = (1U << options->pb) - 1;
883
884 // Range decoder
885 rc_reset(coder->rc);
886
887 // Bit and bittree decoders
888 for (uint32_t i = 0; i < STATES; ++i) {
889 for (uint32_t j = 0; j <= coder->pos_mask; ++j) {
890 bit_reset(coder->is_match[i][j]);
891 bit_reset(coder->is_rep0_long[i][j]);
892 }
893
894 bit_reset(coder->is_rep[i]);
895 bit_reset(coder->is_rep0[i]);
896 bit_reset(coder->is_rep1[i]);
897 bit_reset(coder->is_rep2[i]);
898 }
899
900 for (uint32_t i = 0; i < DIST_STATES; ++i)
901 bittree_reset(coder->dist_slot[i], DIST_SLOT_BITS);
902
903 for (uint32_t i = 0; i < FULL_DISTANCES - DIST_MODEL_END; ++i)
904 bit_reset(coder->pos_special[i]);
905
906 bittree_reset(coder->pos_align, ALIGN_BITS);
907
908 // Len decoders (also bit/bittree)
909 const uint32_t num_pos_states = 1U << options->pb;
910 bit_reset(coder->match_len_decoder.choice);
911 bit_reset(coder->match_len_decoder.choice2);
912 bit_reset(coder->rep_len_decoder.choice);
913 bit_reset(coder->rep_len_decoder.choice2);
914
915 for (uint32_t pos_state = 0; pos_state < num_pos_states; ++pos_state) {
916 bittree_reset(coder->match_len_decoder.low[pos_state],
917 LEN_LOW_BITS);
918 bittree_reset(coder->match_len_decoder.mid[pos_state],
919 LEN_MID_BITS);
920
921 bittree_reset(coder->rep_len_decoder.low[pos_state],
922 LEN_LOW_BITS);
923 bittree_reset(coder->rep_len_decoder.mid[pos_state],
924 LEN_MID_BITS);
925 }
926
927 bittree_reset(coder->match_len_decoder.high, LEN_HIGH_BITS);
928 bittree_reset(coder->rep_len_decoder.high, LEN_HIGH_BITS);
929
930 coder->sequence = SEQ_IS_MATCH;
931 coder->probs = NULL;
932 coder->symbol = 0;
933 coder->limit = 0;
934 coder->offset = 0;
935 coder->len = 0;
936
937 return;
938 }
939
940
941 extern lzma_ret
942 lzma_lzma_decoder_create(lzma_lz_decoder *lz, const lzma_allocator *allocator,
943 const void *opt, lzma_lz_options *lz_options)
944 {
945 if (lz->coder == NULL) {
946 lz->coder = lzma_alloc(sizeof(lzma_lzma1_decoder), allocator);
947 if (lz->coder == NULL)
948 return LZMA_MEM_ERROR;
949
950 lz->code = &lzma_decode;
951 lz->reset = &lzma_decoder_reset;
952 lz->set_uncompressed = &lzma_decoder_uncompressed;
953 }
954
955 // All dictionary sizes are OK here. LZ decoder will take care of
956 // the special cases.
957 const lzma_options_lzma *options = opt;
958 lz_options->dict_size = options->dict_size;
959 lz_options->preset_dict = options->preset_dict;
960 lz_options->preset_dict_size = options->preset_dict_size;
961
962 return LZMA_OK;
963 }
964
965
966 /// Allocate and initialize LZMA decoder. This is used only via LZ
967 /// initialization (lzma_lzma_decoder_init() passes function pointer to
968 /// the LZ initialization).
969 static lzma_ret
970 lzma_decoder_init(lzma_lz_decoder *lz, const lzma_allocator *allocator,
971 const void *options, lzma_lz_options *lz_options)
972 {
973 if (!is_lclppb_valid(options))
974 return LZMA_PROG_ERROR;
975
976 return_if_error(lzma_lzma_decoder_create(
977 lz, allocator, options, lz_options));
978
979 lzma_decoder_reset(lz->coder, options);
980 lzma_decoder_uncompressed(lz->coder, LZMA_VLI_UNKNOWN);
981
982 return LZMA_OK;
983 }
984
985
986 extern lzma_ret
987 lzma_lzma_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
988 const lzma_filter_info *filters)
989 {
990 // LZMA can only be the last filter in the chain. This is enforced
991 // by the raw_decoder initialization.
992 assert(filters[1].init == NULL);
993
994 return lzma_lz_decoder_init(next, allocator, filters,
995 &lzma_decoder_init);
996 }
997
998
999 extern bool
1000 lzma_lzma_lclppb_decode(lzma_options_lzma *options, uint8_t byte)
1001 {
1002 if (byte > (4 * 5 + 4) * 9 + 8)
1003 return true;
1004
1005 // See the file format specification to understand this.
1006 options->pb = byte / (9 * 5);
1007 byte -= options->pb * 9 * 5;
1008 options->lp = byte / 9;
1009 options->lc = byte - options->lp * 9;
1010
1011 return options->lc + options->lp > LZMA_LCLP_MAX;
1012 }
1013
1014
1015 extern uint64_t
1016 lzma_lzma_decoder_memusage_nocheck(const void *options)
1017 {
1018 const lzma_options_lzma *const opt = options;
1019 return sizeof(lzma_lzma1_decoder)
1020 + lzma_lz_decoder_memusage(opt->dict_size);
1021 }
1022
1023
1024 extern uint64_t
1025 lzma_lzma_decoder_memusage(const void *options)
1026 {
1027 if (!is_lclppb_valid(options))
1028 return UINT64_MAX;
1029
1030 return lzma_lzma_decoder_memusage_nocheck(options);
1031 }
1032
1033
1034 extern lzma_ret
1035 lzma_lzma_props_decode(void **options, const lzma_allocator *allocator,
1036 const uint8_t *props, size_t props_size)
1037 {
1038 if (props_size != 5)
1039 return LZMA_OPTIONS_ERROR;
1040
1041 lzma_options_lzma *opt
1042 = lzma_alloc(sizeof(lzma_options_lzma), allocator);
1043 if (opt == NULL)
1044 return LZMA_MEM_ERROR;
1045
1046 if (lzma_lzma_lclppb_decode(opt, props[0]))
1047 goto error;
1048
1049 // All dictionary sizes are accepted, including zero. LZ decoder
1050 // will automatically use a dictionary at least a few KiB even if
1051 // a smaller dictionary is requested.
1052 opt->dict_size = unaligned_read32le(props + 1);
1053
1054 opt->preset_dict = NULL;
1055 opt->preset_dict_size = 0;
1056
1057 *options = opt;
1058
1059 return LZMA_OK;
1060
1061 error:
1062 lzma_free(opt, allocator);
1063 return LZMA_OPTIONS_ERROR;
1064 }
XZ Utils for Debian