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Diffstat (limited to 'lib/xz/xz_dec_lzma2.c')
-rw-r--r-- | lib/xz/xz_dec_lzma2.c | 1171 |
1 files changed, 1171 insertions, 0 deletions
diff --git a/lib/xz/xz_dec_lzma2.c b/lib/xz/xz_dec_lzma2.c new file mode 100644 index 000000000000..ea5fa4fe9d67 --- /dev/null +++ b/lib/xz/xz_dec_lzma2.c | |||
@@ -0,0 +1,1171 @@ | |||
1 | /* | ||
2 | * LZMA2 decoder | ||
3 | * | ||
4 | * Authors: Lasse Collin <lasse.collin@tukaani.org> | ||
5 | * Igor Pavlov <http://7-zip.org/> | ||
6 | * | ||
7 | * This file has been put into the public domain. | ||
8 | * You can do whatever you want with this file. | ||
9 | */ | ||
10 | |||
11 | #include "xz_private.h" | ||
12 | #include "xz_lzma2.h" | ||
13 | |||
14 | /* | ||
15 | * Range decoder initialization eats the first five bytes of each LZMA chunk. | ||
16 | */ | ||
17 | #define RC_INIT_BYTES 5 | ||
18 | |||
19 | /* | ||
20 | * Minimum number of usable input buffer to safely decode one LZMA symbol. | ||
21 | * The worst case is that we decode 22 bits using probabilities and 26 | ||
22 | * direct bits. This may decode at maximum of 20 bytes of input. However, | ||
23 | * lzma_main() does an extra normalization before returning, thus we | ||
24 | * need to put 21 here. | ||
25 | */ | ||
26 | #define LZMA_IN_REQUIRED 21 | ||
27 | |||
28 | /* | ||
29 | * Dictionary (history buffer) | ||
30 | * | ||
31 | * These are always true: | ||
32 | * start <= pos <= full <= end | ||
33 | * pos <= limit <= end | ||
34 | * | ||
35 | * In multi-call mode, also these are true: | ||
36 | * end == size | ||
37 | * size <= size_max | ||
38 | * allocated <= size | ||
39 | * | ||
40 | * Most of these variables are size_t to support single-call mode, | ||
41 | * in which the dictionary variables address the actual output | ||
42 | * buffer directly. | ||
43 | */ | ||
44 | struct dictionary { | ||
45 | /* Beginning of the history buffer */ | ||
46 | uint8_t *buf; | ||
47 | |||
48 | /* Old position in buf (before decoding more data) */ | ||
49 | size_t start; | ||
50 | |||
51 | /* Position in buf */ | ||
52 | size_t pos; | ||
53 | |||
54 | /* | ||
55 | * How full dictionary is. This is used to detect corrupt input that | ||
56 | * would read beyond the beginning of the uncompressed stream. | ||
57 | */ | ||
58 | size_t full; | ||
59 | |||
60 | /* Write limit; we don't write to buf[limit] or later bytes. */ | ||
61 | size_t limit; | ||
62 | |||
63 | /* | ||
64 | * End of the dictionary buffer. In multi-call mode, this is | ||
65 | * the same as the dictionary size. In single-call mode, this | ||
66 | * indicates the size of the output buffer. | ||
67 | */ | ||
68 | size_t end; | ||
69 | |||
70 | /* | ||
71 | * Size of the dictionary as specified in Block Header. This is used | ||
72 | * together with "full" to detect corrupt input that would make us | ||
73 | * read beyond the beginning of the uncompressed stream. | ||
74 | */ | ||
75 | uint32_t size; | ||
76 | |||
77 | /* | ||
78 | * Maximum allowed dictionary size in multi-call mode. | ||
79 | * This is ignored in single-call mode. | ||
80 | */ | ||
81 | uint32_t size_max; | ||
82 | |||
83 | /* | ||
84 | * Amount of memory currently allocated for the dictionary. | ||
85 | * This is used only with XZ_DYNALLOC. (With XZ_PREALLOC, | ||
86 | * size_max is always the same as the allocated size.) | ||
87 | */ | ||
88 | uint32_t allocated; | ||
89 | |||
90 | /* Operation mode */ | ||
91 | enum xz_mode mode; | ||
92 | }; | ||
93 | |||
94 | /* Range decoder */ | ||
95 | struct rc_dec { | ||
96 | uint32_t range; | ||
97 | uint32_t code; | ||
98 | |||
99 | /* | ||
100 | * Number of initializing bytes remaining to be read | ||
101 | * by rc_read_init(). | ||
102 | */ | ||
103 | uint32_t init_bytes_left; | ||
104 | |||
105 | /* | ||
106 | * Buffer from which we read our input. It can be either | ||
107 | * temp.buf or the caller-provided input buffer. | ||
108 | */ | ||
109 | const uint8_t *in; | ||
110 | size_t in_pos; | ||
111 | size_t in_limit; | ||
112 | }; | ||
113 | |||
114 | /* Probabilities for a length decoder. */ | ||
115 | struct lzma_len_dec { | ||
116 | /* Probability of match length being at least 10 */ | ||
117 | uint16_t choice; | ||
118 | |||
119 | /* Probability of match length being at least 18 */ | ||
120 | uint16_t choice2; | ||
121 | |||
122 | /* Probabilities for match lengths 2-9 */ | ||
123 | uint16_t low[POS_STATES_MAX][LEN_LOW_SYMBOLS]; | ||
124 | |||
125 | /* Probabilities for match lengths 10-17 */ | ||
126 | uint16_t mid[POS_STATES_MAX][LEN_MID_SYMBOLS]; | ||
127 | |||
128 | /* Probabilities for match lengths 18-273 */ | ||
129 | uint16_t high[LEN_HIGH_SYMBOLS]; | ||
130 | }; | ||
131 | |||
132 | struct lzma_dec { | ||
133 | /* Distances of latest four matches */ | ||
134 | uint32_t rep0; | ||
135 | uint32_t rep1; | ||
136 | uint32_t rep2; | ||
137 | uint32_t rep3; | ||
138 | |||
139 | /* Types of the most recently seen LZMA symbols */ | ||
140 | enum lzma_state state; | ||
141 | |||
142 | /* | ||
143 | * Length of a match. This is updated so that dict_repeat can | ||
144 | * be called again to finish repeating the whole match. | ||
145 | */ | ||
146 | uint32_t len; | ||
147 | |||
148 | /* | ||
149 | * LZMA properties or related bit masks (number of literal | ||
150 | * context bits, a mask dervied from the number of literal | ||
151 | * position bits, and a mask dervied from the number | ||
152 | * position bits) | ||
153 | */ | ||
154 | uint32_t lc; | ||
155 | uint32_t literal_pos_mask; /* (1 << lp) - 1 */ | ||
156 | uint32_t pos_mask; /* (1 << pb) - 1 */ | ||
157 | |||
158 | /* If 1, it's a match. Otherwise it's a single 8-bit literal. */ | ||
159 | uint16_t is_match[STATES][POS_STATES_MAX]; | ||
160 | |||
161 | /* If 1, it's a repeated match. The distance is one of rep0 .. rep3. */ | ||
162 | uint16_t is_rep[STATES]; | ||
163 | |||
164 | /* | ||
165 | * If 0, distance of a repeated match is rep0. | ||
166 | * Otherwise check is_rep1. | ||
167 | */ | ||
168 | uint16_t is_rep0[STATES]; | ||
169 | |||
170 | /* | ||
171 | * If 0, distance of a repeated match is rep1. | ||
172 | * Otherwise check is_rep2. | ||
173 | */ | ||
174 | uint16_t is_rep1[STATES]; | ||
175 | |||
176 | /* If 0, distance of a repeated match is rep2. Otherwise it is rep3. */ | ||
177 | uint16_t is_rep2[STATES]; | ||
178 | |||
179 | /* | ||
180 | * If 1, the repeated match has length of one byte. Otherwise | ||
181 | * the length is decoded from rep_len_decoder. | ||
182 | */ | ||
183 | uint16_t is_rep0_long[STATES][POS_STATES_MAX]; | ||
184 | |||
185 | /* | ||
186 | * Probability tree for the highest two bits of the match | ||
187 | * distance. There is a separate probability tree for match | ||
188 | * lengths of 2 (i.e. MATCH_LEN_MIN), 3, 4, and [5, 273]. | ||
189 | */ | ||
190 | uint16_t dist_slot[DIST_STATES][DIST_SLOTS]; | ||
191 | |||
192 | /* | ||
193 | * Probility trees for additional bits for match distance | ||
194 | * when the distance is in the range [4, 127]. | ||
195 | */ | ||
196 | uint16_t dist_special[FULL_DISTANCES - DIST_MODEL_END]; | ||
197 | |||
198 | /* | ||
199 | * Probability tree for the lowest four bits of a match | ||
200 | * distance that is equal to or greater than 128. | ||
201 | */ | ||
202 | uint16_t dist_align[ALIGN_SIZE]; | ||
203 | |||
204 | /* Length of a normal match */ | ||
205 | struct lzma_len_dec match_len_dec; | ||
206 | |||
207 | /* Length of a repeated match */ | ||
208 | struct lzma_len_dec rep_len_dec; | ||
209 | |||
210 | /* Probabilities of literals */ | ||
211 | uint16_t literal[LITERAL_CODERS_MAX][LITERAL_CODER_SIZE]; | ||
212 | }; | ||
213 | |||
214 | struct lzma2_dec { | ||
215 | /* Position in xz_dec_lzma2_run(). */ | ||
216 | enum lzma2_seq { | ||
217 | SEQ_CONTROL, | ||
218 | SEQ_UNCOMPRESSED_1, | ||
219 | SEQ_UNCOMPRESSED_2, | ||
220 | SEQ_COMPRESSED_0, | ||
221 | SEQ_COMPRESSED_1, | ||
222 | SEQ_PROPERTIES, | ||
223 | SEQ_LZMA_PREPARE, | ||
224 | SEQ_LZMA_RUN, | ||
225 | SEQ_COPY | ||
226 | } sequence; | ||
227 | |||
228 | /* Next position after decoding the compressed size of the chunk. */ | ||
229 | enum lzma2_seq next_sequence; | ||
230 | |||
231 | /* Uncompressed size of LZMA chunk (2 MiB at maximum) */ | ||
232 | uint32_t uncompressed; | ||
233 | |||
234 | /* | ||
235 | * Compressed size of LZMA chunk or compressed/uncompressed | ||
236 | * size of uncompressed chunk (64 KiB at maximum) | ||
237 | */ | ||
238 | uint32_t compressed; | ||
239 | |||
240 | /* | ||
241 | * True if dictionary reset is needed. This is false before | ||
242 | * the first chunk (LZMA or uncompressed). | ||
243 | */ | ||
244 | bool need_dict_reset; | ||
245 | |||
246 | /* | ||
247 | * True if new LZMA properties are needed. This is false | ||
248 | * before the first LZMA chunk. | ||
249 | */ | ||
250 | bool need_props; | ||
251 | }; | ||
252 | |||
253 | struct xz_dec_lzma2 { | ||
254 | /* | ||
255 | * The order below is important on x86 to reduce code size and | ||
256 | * it shouldn't hurt on other platforms. Everything up to and | ||
257 | * including lzma.pos_mask are in the first 128 bytes on x86-32, | ||
258 | * which allows using smaller instructions to access those | ||
259 | * variables. On x86-64, fewer variables fit into the first 128 | ||
260 | * bytes, but this is still the best order without sacrificing | ||
261 | * the readability by splitting the structures. | ||
262 | */ | ||
263 | struct rc_dec rc; | ||
264 | struct dictionary dict; | ||
265 | struct lzma2_dec lzma2; | ||
266 | struct lzma_dec lzma; | ||
267 | |||
268 | /* | ||
269 | * Temporary buffer which holds small number of input bytes between | ||
270 | * decoder calls. See lzma2_lzma() for details. | ||
271 | */ | ||
272 | struct { | ||
273 | uint32_t size; | ||
274 | uint8_t buf[3 * LZMA_IN_REQUIRED]; | ||
275 | } temp; | ||
276 | }; | ||
277 | |||
278 | /************** | ||
279 | * Dictionary * | ||
280 | **************/ | ||
281 | |||
282 | /* | ||
283 | * Reset the dictionary state. When in single-call mode, set up the beginning | ||
284 | * of the dictionary to point to the actual output buffer. | ||
285 | */ | ||
286 | static void dict_reset(struct dictionary *dict, struct xz_buf *b) | ||
287 | { | ||
288 | if (DEC_IS_SINGLE(dict->mode)) { | ||
289 | dict->buf = b->out + b->out_pos; | ||
290 | dict->end = b->out_size - b->out_pos; | ||
291 | } | ||
292 | |||
293 | dict->start = 0; | ||
294 | dict->pos = 0; | ||
295 | dict->limit = 0; | ||
296 | dict->full = 0; | ||
297 | } | ||
298 | |||
299 | /* Set dictionary write limit */ | ||
300 | static void dict_limit(struct dictionary *dict, size_t out_max) | ||
301 | { | ||
302 | if (dict->end - dict->pos <= out_max) | ||
303 | dict->limit = dict->end; | ||
304 | else | ||
305 | dict->limit = dict->pos + out_max; | ||
306 | } | ||
307 | |||
308 | /* Return true if at least one byte can be written into the dictionary. */ | ||
309 | static inline bool dict_has_space(const struct dictionary *dict) | ||
310 | { | ||
311 | return dict->pos < dict->limit; | ||
312 | } | ||
313 | |||
314 | /* | ||
315 | * Get a byte from the dictionary at the given distance. The distance is | ||
316 | * assumed to valid, or as a special case, zero when the dictionary is | ||
317 | * still empty. This special case is needed for single-call decoding to | ||
318 | * avoid writing a '\0' to the end of the destination buffer. | ||
319 | */ | ||
320 | static inline uint32_t dict_get(const struct dictionary *dict, uint32_t dist) | ||
321 | { | ||
322 | size_t offset = dict->pos - dist - 1; | ||
323 | |||
324 | if (dist >= dict->pos) | ||
325 | offset += dict->end; | ||
326 | |||
327 | return dict->full > 0 ? dict->buf[offset] : 0; | ||
328 | } | ||
329 | |||
330 | /* | ||
331 | * Put one byte into the dictionary. It is assumed that there is space for it. | ||
332 | */ | ||
333 | static inline void dict_put(struct dictionary *dict, uint8_t byte) | ||
334 | { | ||
335 | dict->buf[dict->pos++] = byte; | ||
336 | |||
337 | if (dict->full < dict->pos) | ||
338 | dict->full = dict->pos; | ||
339 | } | ||
340 | |||
341 | /* | ||
342 | * Repeat given number of bytes from the given distance. If the distance is | ||
343 | * invalid, false is returned. On success, true is returned and *len is | ||
344 | * updated to indicate how many bytes were left to be repeated. | ||
345 | */ | ||
346 | static bool dict_repeat(struct dictionary *dict, uint32_t *len, uint32_t dist) | ||
347 | { | ||
348 | size_t back; | ||
349 | uint32_t left; | ||
350 | |||
351 | if (dist >= dict->full || dist >= dict->size) | ||
352 | return false; | ||
353 | |||
354 | left = min_t(size_t, dict->limit - dict->pos, *len); | ||
355 | *len -= left; | ||
356 | |||
357 | back = dict->pos - dist - 1; | ||
358 | if (dist >= dict->pos) | ||
359 | back += dict->end; | ||
360 | |||
361 | do { | ||
362 | dict->buf[dict->pos++] = dict->buf[back++]; | ||
363 | if (back == dict->end) | ||
364 | back = 0; | ||
365 | } while (--left > 0); | ||
366 | |||
367 | if (dict->full < dict->pos) | ||
368 | dict->full = dict->pos; | ||
369 | |||
370 | return true; | ||
371 | } | ||
372 | |||
373 | /* Copy uncompressed data as is from input to dictionary and output buffers. */ | ||
374 | static void dict_uncompressed(struct dictionary *dict, struct xz_buf *b, | ||
375 | uint32_t *left) | ||
376 | { | ||
377 | size_t copy_size; | ||
378 | |||
379 | while (*left > 0 && b->in_pos < b->in_size | ||
380 | && b->out_pos < b->out_size) { | ||
381 | copy_size = min(b->in_size - b->in_pos, | ||
382 | b->out_size - b->out_pos); | ||
383 | if (copy_size > dict->end - dict->pos) | ||
384 | copy_size = dict->end - dict->pos; | ||
385 | if (copy_size > *left) | ||
386 | copy_size = *left; | ||
387 | |||
388 | *left -= copy_size; | ||
389 | |||
390 | memcpy(dict->buf + dict->pos, b->in + b->in_pos, copy_size); | ||
391 | dict->pos += copy_size; | ||
392 | |||
393 | if (dict->full < dict->pos) | ||
394 | dict->full = dict->pos; | ||
395 | |||
396 | if (DEC_IS_MULTI(dict->mode)) { | ||
397 | if (dict->pos == dict->end) | ||
398 | dict->pos = 0; | ||
399 | |||
400 | memcpy(b->out + b->out_pos, b->in + b->in_pos, | ||
401 | copy_size); | ||
402 | } | ||
403 | |||
404 | dict->start = dict->pos; | ||
405 | |||
406 | b->out_pos += copy_size; | ||
407 | b->in_pos += copy_size; | ||
408 | } | ||
409 | } | ||
410 | |||
411 | /* | ||
412 | * Flush pending data from dictionary to b->out. It is assumed that there is | ||
413 | * enough space in b->out. This is guaranteed because caller uses dict_limit() | ||
414 | * before decoding data into the dictionary. | ||
415 | */ | ||
416 | static uint32_t dict_flush(struct dictionary *dict, struct xz_buf *b) | ||
417 | { | ||
418 | size_t copy_size = dict->pos - dict->start; | ||
419 | |||
420 | if (DEC_IS_MULTI(dict->mode)) { | ||
421 | if (dict->pos == dict->end) | ||
422 | dict->pos = 0; | ||
423 | |||
424 | memcpy(b->out + b->out_pos, dict->buf + dict->start, | ||
425 | copy_size); | ||
426 | } | ||
427 | |||
428 | dict->start = dict->pos; | ||
429 | b->out_pos += copy_size; | ||
430 | return copy_size; | ||
431 | } | ||
432 | |||
433 | /***************** | ||
434 | * Range decoder * | ||
435 | *****************/ | ||
436 | |||
437 | /* Reset the range decoder. */ | ||
438 | static void rc_reset(struct rc_dec *rc) | ||
439 | { | ||
440 | rc->range = (uint32_t)-1; | ||
441 | rc->code = 0; | ||
442 | rc->init_bytes_left = RC_INIT_BYTES; | ||
443 | } | ||
444 | |||
445 | /* | ||
446 | * Read the first five initial bytes into rc->code if they haven't been | ||
447 | * read already. (Yes, the first byte gets completely ignored.) | ||
448 | */ | ||
449 | static bool rc_read_init(struct rc_dec *rc, struct xz_buf *b) | ||
450 | { | ||
451 | while (rc->init_bytes_left > 0) { | ||
452 | if (b->in_pos == b->in_size) | ||
453 | return false; | ||
454 | |||
455 | rc->code = (rc->code << 8) + b->in[b->in_pos++]; | ||
456 | --rc->init_bytes_left; | ||
457 | } | ||
458 | |||
459 | return true; | ||
460 | } | ||
461 | |||
462 | /* Return true if there may not be enough input for the next decoding loop. */ | ||
463 | static inline bool rc_limit_exceeded(const struct rc_dec *rc) | ||
464 | { | ||
465 | return rc->in_pos > rc->in_limit; | ||
466 | } | ||
467 | |||
468 | /* | ||
469 | * Return true if it is possible (from point of view of range decoder) that | ||
470 | * we have reached the end of the LZMA chunk. | ||
471 | */ | ||
472 | static inline bool rc_is_finished(const struct rc_dec *rc) | ||
473 | { | ||
474 | return rc->code == 0; | ||
475 | } | ||
476 | |||
477 | /* Read the next input byte if needed. */ | ||
478 | static __always_inline void rc_normalize(struct rc_dec *rc) | ||
479 | { | ||
480 | if (rc->range < RC_TOP_VALUE) { | ||
481 | rc->range <<= RC_SHIFT_BITS; | ||
482 | rc->code = (rc->code << RC_SHIFT_BITS) + rc->in[rc->in_pos++]; | ||
483 | } | ||
484 | } | ||
485 | |||
486 | /* | ||
487 | * Decode one bit. In some versions, this function has been splitted in three | ||
488 | * functions so that the compiler is supposed to be able to more easily avoid | ||
489 | * an extra branch. In this particular version of the LZMA decoder, this | ||
490 | * doesn't seem to be a good idea (tested with GCC 3.3.6, 3.4.6, and 4.3.3 | ||
491 | * on x86). Using a non-splitted version results in nicer looking code too. | ||
492 | * | ||
493 | * NOTE: This must return an int. Do not make it return a bool or the speed | ||
494 | * of the code generated by GCC 3.x decreases 10-15 %. (GCC 4.3 doesn't care, | ||
495 | * and it generates 10-20 % faster code than GCC 3.x from this file anyway.) | ||
496 | */ | ||
497 | static __always_inline int rc_bit(struct rc_dec *rc, uint16_t *prob) | ||
498 | { | ||
499 | uint32_t bound; | ||
500 | int bit; | ||
501 | |||
502 | rc_normalize(rc); | ||
503 | bound = (rc->range >> RC_BIT_MODEL_TOTAL_BITS) * *prob; | ||
504 | if (rc->code < bound) { | ||
505 | rc->range = bound; | ||
506 | *prob += (RC_BIT_MODEL_TOTAL - *prob) >> RC_MOVE_BITS; | ||
507 | bit = 0; | ||
508 | } else { | ||
509 | rc->range -= bound; | ||
510 | rc->code -= bound; | ||
511 | *prob -= *prob >> RC_MOVE_BITS; | ||
512 | bit = 1; | ||
513 | } | ||
514 | |||
515 | return bit; | ||
516 | } | ||
517 | |||
518 | /* Decode a bittree starting from the most significant bit. */ | ||
519 | static __always_inline uint32_t rc_bittree(struct rc_dec *rc, | ||
520 | uint16_t *probs, uint32_t limit) | ||
521 | { | ||
522 | uint32_t symbol = 1; | ||
523 | |||
524 | do { | ||
525 | if (rc_bit(rc, &probs[symbol])) | ||
526 | symbol = (symbol << 1) + 1; | ||
527 | else | ||
528 | symbol <<= 1; | ||
529 | } while (symbol < limit); | ||
530 | |||
531 | return symbol; | ||
532 | } | ||
533 | |||
534 | /* Decode a bittree starting from the least significant bit. */ | ||
535 | static __always_inline void rc_bittree_reverse(struct rc_dec *rc, | ||
536 | uint16_t *probs, | ||
537 | uint32_t *dest, uint32_t limit) | ||
538 | { | ||
539 | uint32_t symbol = 1; | ||
540 | uint32_t i = 0; | ||
541 | |||
542 | do { | ||
543 | if (rc_bit(rc, &probs[symbol])) { | ||
544 | symbol = (symbol << 1) + 1; | ||
545 | *dest += 1 << i; | ||
546 | } else { | ||
547 | symbol <<= 1; | ||
548 | } | ||
549 | } while (++i < limit); | ||
550 | } | ||
551 | |||
552 | /* Decode direct bits (fixed fifty-fifty probability) */ | ||
553 | static inline void rc_direct(struct rc_dec *rc, uint32_t *dest, uint32_t limit) | ||
554 | { | ||
555 | uint32_t mask; | ||
556 | |||
557 | do { | ||
558 | rc_normalize(rc); | ||
559 | rc->range >>= 1; | ||
560 | rc->code -= rc->range; | ||
561 | mask = (uint32_t)0 - (rc->code >> 31); | ||
562 | rc->code += rc->range & mask; | ||
563 | *dest = (*dest << 1) + (mask + 1); | ||
564 | } while (--limit > 0); | ||
565 | } | ||
566 | |||
567 | /******** | ||
568 | * LZMA * | ||
569 | ********/ | ||
570 | |||
571 | /* Get pointer to literal coder probability array. */ | ||
572 | static uint16_t *lzma_literal_probs(struct xz_dec_lzma2 *s) | ||
573 | { | ||
574 | uint32_t prev_byte = dict_get(&s->dict, 0); | ||
575 | uint32_t low = prev_byte >> (8 - s->lzma.lc); | ||
576 | uint32_t high = (s->dict.pos & s->lzma.literal_pos_mask) << s->lzma.lc; | ||
577 | return s->lzma.literal[low + high]; | ||
578 | } | ||
579 | |||
580 | /* Decode a literal (one 8-bit byte) */ | ||
581 | static void lzma_literal(struct xz_dec_lzma2 *s) | ||
582 | { | ||
583 | uint16_t *probs; | ||
584 | uint32_t symbol; | ||
585 | uint32_t match_byte; | ||
586 | uint32_t match_bit; | ||
587 | uint32_t offset; | ||
588 | uint32_t i; | ||
589 | |||
590 | probs = lzma_literal_probs(s); | ||
591 | |||
592 | if (lzma_state_is_literal(s->lzma.state)) { | ||
593 | symbol = rc_bittree(&s->rc, probs, 0x100); | ||
594 | } else { | ||
595 | symbol = 1; | ||
596 | match_byte = dict_get(&s->dict, s->lzma.rep0) << 1; | ||
597 | offset = 0x100; | ||
598 | |||
599 | do { | ||
600 | match_bit = match_byte & offset; | ||
601 | match_byte <<= 1; | ||
602 | i = offset + match_bit + symbol; | ||
603 | |||
604 | if (rc_bit(&s->rc, &probs[i])) { | ||
605 | symbol = (symbol << 1) + 1; | ||
606 | offset &= match_bit; | ||
607 | } else { | ||
608 | symbol <<= 1; | ||
609 | offset &= ~match_bit; | ||
610 | } | ||
611 | } while (symbol < 0x100); | ||
612 | } | ||
613 | |||
614 | dict_put(&s->dict, (uint8_t)symbol); | ||
615 | lzma_state_literal(&s->lzma.state); | ||
616 | } | ||
617 | |||
618 | /* Decode the length of the match into s->lzma.len. */ | ||
619 | static void lzma_len(struct xz_dec_lzma2 *s, struct lzma_len_dec *l, | ||
620 | uint32_t pos_state) | ||
621 | { | ||
622 | uint16_t *probs; | ||
623 | uint32_t limit; | ||
624 | |||
625 | if (!rc_bit(&s->rc, &l->choice)) { | ||
626 | probs = l->low[pos_state]; | ||
627 | limit = LEN_LOW_SYMBOLS; | ||
628 | s->lzma.len = MATCH_LEN_MIN; | ||
629 | } else { | ||
630 | if (!rc_bit(&s->rc, &l->choice2)) { | ||
631 | probs = l->mid[pos_state]; | ||
632 | limit = LEN_MID_SYMBOLS; | ||
633 | s->lzma.len = MATCH_LEN_MIN + LEN_LOW_SYMBOLS; | ||
634 | } else { | ||
635 | probs = l->high; | ||
636 | limit = LEN_HIGH_SYMBOLS; | ||
637 | s->lzma.len = MATCH_LEN_MIN + LEN_LOW_SYMBOLS | ||
638 | + LEN_MID_SYMBOLS; | ||
639 | } | ||
640 | } | ||
641 | |||
642 | s->lzma.len += rc_bittree(&s->rc, probs, limit) - limit; | ||
643 | } | ||
644 | |||
645 | /* Decode a match. The distance will be stored in s->lzma.rep0. */ | ||
646 | static void lzma_match(struct xz_dec_lzma2 *s, uint32_t pos_state) | ||
647 | { | ||
648 | uint16_t *probs; | ||
649 | uint32_t dist_slot; | ||
650 | uint32_t limit; | ||
651 | |||
652 | lzma_state_match(&s->lzma.state); | ||
653 | |||
654 | s->lzma.rep3 = s->lzma.rep2; | ||
655 | s->lzma.rep2 = s->lzma.rep1; | ||
656 | s->lzma.rep1 = s->lzma.rep0; | ||
657 | |||
658 | lzma_len(s, &s->lzma.match_len_dec, pos_state); | ||
659 | |||
660 | probs = s->lzma.dist_slot[lzma_get_dist_state(s->lzma.len)]; | ||
661 | dist_slot = rc_bittree(&s->rc, probs, DIST_SLOTS) - DIST_SLOTS; | ||
662 | |||
663 | if (dist_slot < DIST_MODEL_START) { | ||
664 | s->lzma.rep0 = dist_slot; | ||
665 | } else { | ||
666 | limit = (dist_slot >> 1) - 1; | ||
667 | s->lzma.rep0 = 2 + (dist_slot & 1); | ||
668 | |||
669 | if (dist_slot < DIST_MODEL_END) { | ||
670 | s->lzma.rep0 <<= limit; | ||
671 | probs = s->lzma.dist_special + s->lzma.rep0 | ||
672 | - dist_slot - 1; | ||
673 | rc_bittree_reverse(&s->rc, probs, | ||
674 | &s->lzma.rep0, limit); | ||
675 | } else { | ||
676 | rc_direct(&s->rc, &s->lzma.rep0, limit - ALIGN_BITS); | ||
677 | s->lzma.rep0 <<= ALIGN_BITS; | ||
678 | rc_bittree_reverse(&s->rc, s->lzma.dist_align, | ||
679 | &s->lzma.rep0, ALIGN_BITS); | ||
680 | } | ||
681 | } | ||
682 | } | ||
683 | |||
684 | /* | ||
685 | * Decode a repeated match. The distance is one of the four most recently | ||
686 | * seen matches. The distance will be stored in s->lzma.rep0. | ||
687 | */ | ||
688 | static void lzma_rep_match(struct xz_dec_lzma2 *s, uint32_t pos_state) | ||
689 | { | ||
690 | uint32_t tmp; | ||
691 | |||
692 | if (!rc_bit(&s->rc, &s->lzma.is_rep0[s->lzma.state])) { | ||
693 | if (!rc_bit(&s->rc, &s->lzma.is_rep0_long[ | ||
694 | s->lzma.state][pos_state])) { | ||
695 | lzma_state_short_rep(&s->lzma.state); | ||
696 | s->lzma.len = 1; | ||
697 | return; | ||
698 | } | ||
699 | } else { | ||
700 | if (!rc_bit(&s->rc, &s->lzma.is_rep1[s->lzma.state])) { | ||
701 | tmp = s->lzma.rep1; | ||
702 | } else { | ||
703 | if (!rc_bit(&s->rc, &s->lzma.is_rep2[s->lzma.state])) { | ||
704 | tmp = s->lzma.rep2; | ||
705 | } else { | ||
706 | tmp = s->lzma.rep3; | ||
707 | s->lzma.rep3 = s->lzma.rep2; | ||
708 | } | ||
709 | |||
710 | s->lzma.rep2 = s->lzma.rep1; | ||
711 | } | ||
712 | |||
713 | s->lzma.rep1 = s->lzma.rep0; | ||
714 | s->lzma.rep0 = tmp; | ||
715 | } | ||
716 | |||
717 | lzma_state_long_rep(&s->lzma.state); | ||
718 | lzma_len(s, &s->lzma.rep_len_dec, pos_state); | ||
719 | } | ||
720 | |||
721 | /* LZMA decoder core */ | ||
722 | static bool lzma_main(struct xz_dec_lzma2 *s) | ||
723 | { | ||
724 | uint32_t pos_state; | ||
725 | |||
726 | /* | ||
727 | * If the dictionary was reached during the previous call, try to | ||
728 | * finish the possibly pending repeat in the dictionary. | ||
729 | */ | ||
730 | if (dict_has_space(&s->dict) && s->lzma.len > 0) | ||
731 | dict_repeat(&s->dict, &s->lzma.len, s->lzma.rep0); | ||
732 | |||
733 | /* | ||
734 | * Decode more LZMA symbols. One iteration may consume up to | ||
735 | * LZMA_IN_REQUIRED - 1 bytes. | ||
736 | */ | ||
737 | while (dict_has_space(&s->dict) && !rc_limit_exceeded(&s->rc)) { | ||
738 | pos_state = s->dict.pos & s->lzma.pos_mask; | ||
739 | |||
740 | if (!rc_bit(&s->rc, &s->lzma.is_match[ | ||
741 | s->lzma.state][pos_state])) { | ||
742 | lzma_literal(s); | ||
743 | } else { | ||
744 | if (rc_bit(&s->rc, &s->lzma.is_rep[s->lzma.state])) | ||
745 | lzma_rep_match(s, pos_state); | ||
746 | else | ||
747 | lzma_match(s, pos_state); | ||
748 | |||
749 | if (!dict_repeat(&s->dict, &s->lzma.len, s->lzma.rep0)) | ||
750 | return false; | ||
751 | } | ||
752 | } | ||
753 | |||
754 | /* | ||
755 | * Having the range decoder always normalized when we are outside | ||
756 | * this function makes it easier to correctly handle end of the chunk. | ||
757 | */ | ||
758 | rc_normalize(&s->rc); | ||
759 | |||
760 | return true; | ||
761 | } | ||
762 | |||
763 | /* | ||
764 | * Reset the LZMA decoder and range decoder state. Dictionary is nore reset | ||
765 | * here, because LZMA state may be reset without resetting the dictionary. | ||
766 | */ | ||
767 | static void lzma_reset(struct xz_dec_lzma2 *s) | ||
768 | { | ||
769 | uint16_t *probs; | ||
770 | size_t i; | ||
771 | |||
772 | s->lzma.state = STATE_LIT_LIT; | ||
773 | s->lzma.rep0 = 0; | ||
774 | s->lzma.rep1 = 0; | ||
775 | s->lzma.rep2 = 0; | ||
776 | s->lzma.rep3 = 0; | ||
777 | |||
778 | /* | ||
779 | * All probabilities are initialized to the same value. This hack | ||
780 | * makes the code smaller by avoiding a separate loop for each | ||
781 | * probability array. | ||
782 | * | ||
783 | * This could be optimized so that only that part of literal | ||
784 | * probabilities that are actually required. In the common case | ||
785 | * we would write 12 KiB less. | ||
786 | */ | ||
787 | probs = s->lzma.is_match[0]; | ||
788 | for (i = 0; i < PROBS_TOTAL; ++i) | ||
789 | probs[i] = RC_BIT_MODEL_TOTAL / 2; | ||
790 | |||
791 | rc_reset(&s->rc); | ||
792 | } | ||
793 | |||
794 | /* | ||
795 | * Decode and validate LZMA properties (lc/lp/pb) and calculate the bit masks | ||
796 | * from the decoded lp and pb values. On success, the LZMA decoder state is | ||
797 | * reset and true is returned. | ||
798 | */ | ||
799 | static bool lzma_props(struct xz_dec_lzma2 *s, uint8_t props) | ||
800 | { | ||
801 | if (props > (4 * 5 + 4) * 9 + 8) | ||
802 | return false; | ||
803 | |||
804 | s->lzma.pos_mask = 0; | ||
805 | while (props >= 9 * 5) { | ||
806 | props -= 9 * 5; | ||
807 | ++s->lzma.pos_mask; | ||
808 | } | ||
809 | |||
810 | s->lzma.pos_mask = (1 << s->lzma.pos_mask) - 1; | ||
811 | |||
812 | s->lzma.literal_pos_mask = 0; | ||
813 | while (props >= 9) { | ||
814 | props -= 9; | ||
815 | ++s->lzma.literal_pos_mask; | ||
816 | } | ||
817 | |||
818 | s->lzma.lc = props; | ||
819 | |||
820 | if (s->lzma.lc + s->lzma.literal_pos_mask > 4) | ||
821 | return false; | ||
822 | |||
823 | s->lzma.literal_pos_mask = (1 << s->lzma.literal_pos_mask) - 1; | ||
824 | |||
825 | lzma_reset(s); | ||
826 | |||
827 | return true; | ||
828 | } | ||
829 | |||
830 | /********* | ||
831 | * LZMA2 * | ||
832 | *********/ | ||
833 | |||
834 | /* | ||
835 | * The LZMA decoder assumes that if the input limit (s->rc.in_limit) hasn't | ||
836 | * been exceeded, it is safe to read up to LZMA_IN_REQUIRED bytes. This | ||
837 | * wrapper function takes care of making the LZMA decoder's assumption safe. | ||
838 | * | ||
839 | * As long as there is plenty of input left to be decoded in the current LZMA | ||
840 | * chunk, we decode directly from the caller-supplied input buffer until | ||
841 | * there's LZMA_IN_REQUIRED bytes left. Those remaining bytes are copied into | ||
842 | * s->temp.buf, which (hopefully) gets filled on the next call to this | ||
843 | * function. We decode a few bytes from the temporary buffer so that we can | ||
844 | * continue decoding from the caller-supplied input buffer again. | ||
845 | */ | ||
846 | static bool lzma2_lzma(struct xz_dec_lzma2 *s, struct xz_buf *b) | ||
847 | { | ||
848 | size_t in_avail; | ||
849 | uint32_t tmp; | ||
850 | |||
851 | in_avail = b->in_size - b->in_pos; | ||
852 | if (s->temp.size > 0 || s->lzma2.compressed == 0) { | ||
853 | tmp = 2 * LZMA_IN_REQUIRED - s->temp.size; | ||
854 | if (tmp > s->lzma2.compressed - s->temp.size) | ||
855 | tmp = s->lzma2.compressed - s->temp.size; | ||
856 | if (tmp > in_avail) | ||
857 | tmp = in_avail; | ||
858 | |||
859 | memcpy(s->temp.buf + s->temp.size, b->in + b->in_pos, tmp); | ||
860 | |||
861 | if (s->temp.size + tmp == s->lzma2.compressed) { | ||
862 | memzero(s->temp.buf + s->temp.size + tmp, | ||
863 | sizeof(s->temp.buf) | ||
864 | - s->temp.size - tmp); | ||
865 | s->rc.in_limit = s->temp.size + tmp; | ||
866 | } else if (s->temp.size + tmp < LZMA_IN_REQUIRED) { | ||
867 | s->temp.size += tmp; | ||
868 | b->in_pos += tmp; | ||
869 | return true; | ||
870 | } else { | ||
871 | s->rc.in_limit = s->temp.size + tmp - LZMA_IN_REQUIRED; | ||
872 | } | ||
873 | |||
874 | s->rc.in = s->temp.buf; | ||
875 | s->rc.in_pos = 0; | ||
876 | |||
877 | if (!lzma_main(s) || s->rc.in_pos > s->temp.size + tmp) | ||
878 | return false; | ||
879 | |||
880 | s->lzma2.compressed -= s->rc.in_pos; | ||
881 | |||
882 | if (s->rc.in_pos < s->temp.size) { | ||
883 | s->temp.size -= s->rc.in_pos; | ||
884 | memmove(s->temp.buf, s->temp.buf + s->rc.in_pos, | ||
885 | s->temp.size); | ||
886 | return true; | ||
887 | } | ||
888 | |||
889 | b->in_pos += s->rc.in_pos - s->temp.size; | ||
890 | s->temp.size = 0; | ||
891 | } | ||
892 | |||
893 | in_avail = b->in_size - b->in_pos; | ||
894 | if (in_avail >= LZMA_IN_REQUIRED) { | ||
895 | s->rc.in = b->in; | ||
896 | s->rc.in_pos = b->in_pos; | ||
897 | |||
898 | if (in_avail >= s->lzma2.compressed + LZMA_IN_REQUIRED) | ||
899 | s->rc.in_limit = b->in_pos + s->lzma2.compressed; | ||
900 | else | ||
901 | s->rc.in_limit = b->in_size - LZMA_IN_REQUIRED; | ||
902 | |||
903 | if (!lzma_main(s)) | ||
904 | return false; | ||
905 | |||
906 | in_avail = s->rc.in_pos - b->in_pos; | ||
907 | if (in_avail > s->lzma2.compressed) | ||
908 | return false; | ||
909 | |||
910 | s->lzma2.compressed -= in_avail; | ||
911 | b->in_pos = s->rc.in_pos; | ||
912 | } | ||
913 | |||
914 | in_avail = b->in_size - b->in_pos; | ||
915 | if (in_avail < LZMA_IN_REQUIRED) { | ||
916 | if (in_avail > s->lzma2.compressed) | ||
917 | in_avail = s->lzma2.compressed; | ||
918 | |||
919 | memcpy(s->temp.buf, b->in + b->in_pos, in_avail); | ||
920 | s->temp.size = in_avail; | ||
921 | b->in_pos += in_avail; | ||
922 | } | ||
923 | |||
924 | return true; | ||
925 | } | ||
926 | |||
927 | /* | ||
928 | * Take care of the LZMA2 control layer, and forward the job of actual LZMA | ||
929 | * decoding or copying of uncompressed chunks to other functions. | ||
930 | */ | ||
931 | XZ_EXTERN enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s, | ||
932 | struct xz_buf *b) | ||
933 | { | ||
934 | uint32_t tmp; | ||
935 | |||
936 | while (b->in_pos < b->in_size || s->lzma2.sequence == SEQ_LZMA_RUN) { | ||
937 | switch (s->lzma2.sequence) { | ||
938 | case SEQ_CONTROL: | ||
939 | /* | ||
940 | * LZMA2 control byte | ||
941 | * | ||
942 | * Exact values: | ||
943 | * 0x00 End marker | ||
944 | * 0x01 Dictionary reset followed by | ||
945 | * an uncompressed chunk | ||
946 | * 0x02 Uncompressed chunk (no dictionary reset) | ||
947 | * | ||
948 | * Highest three bits (s->control & 0xE0): | ||
949 | * 0xE0 Dictionary reset, new properties and state | ||
950 | * reset, followed by LZMA compressed chunk | ||
951 | * 0xC0 New properties and state reset, followed | ||
952 | * by LZMA compressed chunk (no dictionary | ||
953 | * reset) | ||
954 | * 0xA0 State reset using old properties, | ||
955 | * followed by LZMA compressed chunk (no | ||
956 | * dictionary reset) | ||
957 | * 0x80 LZMA chunk (no dictionary or state reset) | ||
958 | * | ||
959 | * For LZMA compressed chunks, the lowest five bits | ||
960 | * (s->control & 1F) are the highest bits of the | ||
961 | * uncompressed size (bits 16-20). | ||
962 | * | ||
963 | * A new LZMA2 stream must begin with a dictionary | ||
964 | * reset. The first LZMA chunk must set new | ||
965 | * properties and reset the LZMA state. | ||
966 | * | ||
967 | * Values that don't match anything described above | ||
968 | * are invalid and we return XZ_DATA_ERROR. | ||
969 | */ | ||
970 | tmp = b->in[b->in_pos++]; | ||
971 | |||
972 | if (tmp >= 0xE0 || tmp == 0x01) { | ||
973 | s->lzma2.need_props = true; | ||
974 | s->lzma2.need_dict_reset = false; | ||
975 | dict_reset(&s->dict, b); | ||
976 | } else if (s->lzma2.need_dict_reset) { | ||
977 | return XZ_DATA_ERROR; | ||
978 | } | ||
979 | |||
980 | if (tmp >= 0x80) { | ||
981 | s->lzma2.uncompressed = (tmp & 0x1F) << 16; | ||
982 | s->lzma2.sequence = SEQ_UNCOMPRESSED_1; | ||
983 | |||
984 | if (tmp >= 0xC0) { | ||
985 | /* | ||
986 | * When there are new properties, | ||
987 | * state reset is done at | ||
988 | * SEQ_PROPERTIES. | ||
989 | */ | ||
990 | s->lzma2.need_props = false; | ||
991 | s->lzma2.next_sequence | ||
992 | = SEQ_PROPERTIES; | ||
993 | |||
994 | } else if (s->lzma2.need_props) { | ||
995 | return XZ_DATA_ERROR; | ||
996 | |||
997 | } else { | ||
998 | s->lzma2.next_sequence | ||
999 | = SEQ_LZMA_PREPARE; | ||
1000 | if (tmp >= 0xA0) | ||
1001 | lzma_reset(s); | ||
1002 | } | ||
1003 | } else { | ||
1004 | if (tmp == 0x00) | ||
1005 | return XZ_STREAM_END; | ||
1006 | |||
1007 | if (tmp > 0x02) | ||
1008 | return XZ_DATA_ERROR; | ||
1009 | |||
1010 | s->lzma2.sequence = SEQ_COMPRESSED_0; | ||
1011 | s->lzma2.next_sequence = SEQ_COPY; | ||
1012 | } | ||
1013 | |||
1014 | break; | ||
1015 | |||
1016 | case SEQ_UNCOMPRESSED_1: | ||
1017 | s->lzma2.uncompressed | ||
1018 | += (uint32_t)b->in[b->in_pos++] << 8; | ||
1019 | s->lzma2.sequence = SEQ_UNCOMPRESSED_2; | ||
1020 | break; | ||
1021 | |||
1022 | case SEQ_UNCOMPRESSED_2: | ||
1023 | s->lzma2.uncompressed | ||
1024 | += (uint32_t)b->in[b->in_pos++] + 1; | ||
1025 | s->lzma2.sequence = SEQ_COMPRESSED_0; | ||
1026 | break; | ||
1027 | |||
1028 | case SEQ_COMPRESSED_0: | ||
1029 | s->lzma2.compressed | ||
1030 | = (uint32_t)b->in[b->in_pos++] << 8; | ||
1031 | s->lzma2.sequence = SEQ_COMPRESSED_1; | ||
1032 | break; | ||
1033 | |||
1034 | case SEQ_COMPRESSED_1: | ||
1035 | s->lzma2.compressed | ||
1036 | += (uint32_t)b->in[b->in_pos++] + 1; | ||
1037 | s->lzma2.sequence = s->lzma2.next_sequence; | ||
1038 | break; | ||
1039 | |||
1040 | case SEQ_PROPERTIES: | ||
1041 | if (!lzma_props(s, b->in[b->in_pos++])) | ||
1042 | return XZ_DATA_ERROR; | ||
1043 | |||
1044 | s->lzma2.sequence = SEQ_LZMA_PREPARE; | ||
1045 | |||
1046 | case SEQ_LZMA_PREPARE: | ||
1047 | if (s->lzma2.compressed < RC_INIT_BYTES) | ||
1048 | return XZ_DATA_ERROR; | ||
1049 | |||
1050 | if (!rc_read_init(&s->rc, b)) | ||
1051 | return XZ_OK; | ||
1052 | |||
1053 | s->lzma2.compressed -= RC_INIT_BYTES; | ||
1054 | s->lzma2.sequence = SEQ_LZMA_RUN; | ||
1055 | |||
1056 | case SEQ_LZMA_RUN: | ||
1057 | /* | ||
1058 | * Set dictionary limit to indicate how much we want | ||
1059 | * to be encoded at maximum. Decode new data into the | ||
1060 | * dictionary. Flush the new data from dictionary to | ||
1061 | * b->out. Check if we finished decoding this chunk. | ||
1062 | * In case the dictionary got full but we didn't fill | ||
1063 | * the output buffer yet, we may run this loop | ||
1064 | * multiple times without changing s->lzma2.sequence. | ||
1065 | */ | ||
1066 | dict_limit(&s->dict, min_t(size_t, | ||
1067 | b->out_size - b->out_pos, | ||
1068 | s->lzma2.uncompressed)); | ||
1069 | if (!lzma2_lzma(s, b)) | ||
1070 | return XZ_DATA_ERROR; | ||
1071 | |||
1072 | s->lzma2.uncompressed -= dict_flush(&s->dict, b); | ||
1073 | |||
1074 | if (s->lzma2.uncompressed == 0) { | ||
1075 | if (s->lzma2.compressed > 0 || s->lzma.len > 0 | ||
1076 | || !rc_is_finished(&s->rc)) | ||
1077 | return XZ_DATA_ERROR; | ||
1078 | |||
1079 | rc_reset(&s->rc); | ||
1080 | s->lzma2.sequence = SEQ_CONTROL; | ||
1081 | |||
1082 | } else if (b->out_pos == b->out_size | ||
1083 | || (b->in_pos == b->in_size | ||
1084 | && s->temp.size | ||
1085 | < s->lzma2.compressed)) { | ||
1086 | return XZ_OK; | ||
1087 | } | ||
1088 | |||
1089 | break; | ||
1090 | |||
1091 | case SEQ_COPY: | ||
1092 | dict_uncompressed(&s->dict, b, &s->lzma2.compressed); | ||
1093 | if (s->lzma2.compressed > 0) | ||
1094 | return XZ_OK; | ||
1095 | |||
1096 | s->lzma2.sequence = SEQ_CONTROL; | ||
1097 | break; | ||
1098 | } | ||
1099 | } | ||
1100 | |||
1101 | return XZ_OK; | ||
1102 | } | ||
1103 | |||
1104 | XZ_EXTERN struct xz_dec_lzma2 *xz_dec_lzma2_create(enum xz_mode mode, | ||
1105 | uint32_t dict_max) | ||
1106 | { | ||
1107 | struct xz_dec_lzma2 *s = kmalloc(sizeof(*s), GFP_KERNEL); | ||
1108 | if (s == NULL) | ||
1109 | return NULL; | ||
1110 | |||
1111 | s->dict.mode = mode; | ||
1112 | s->dict.size_max = dict_max; | ||
1113 | |||
1114 | if (DEC_IS_PREALLOC(mode)) { | ||
1115 | s->dict.buf = vmalloc(dict_max); | ||
1116 | if (s->dict.buf == NULL) { | ||
1117 | kfree(s); | ||
1118 | return NULL; | ||
1119 | } | ||
1120 | } else if (DEC_IS_DYNALLOC(mode)) { | ||
1121 | s->dict.buf = NULL; | ||
1122 | s->dict.allocated = 0; | ||
1123 | } | ||
1124 | |||
1125 | return s; | ||
1126 | } | ||
1127 | |||
1128 | XZ_EXTERN enum xz_ret xz_dec_lzma2_reset(struct xz_dec_lzma2 *s, uint8_t props) | ||
1129 | { | ||
1130 | /* This limits dictionary size to 3 GiB to keep parsing simpler. */ | ||
1131 | if (props > 39) | ||
1132 | return XZ_OPTIONS_ERROR; | ||
1133 | |||
1134 | s->dict.size = 2 + (props & 1); | ||
1135 | s->dict.size <<= (props >> 1) + 11; | ||
1136 | |||
1137 | if (DEC_IS_MULTI(s->dict.mode)) { | ||
1138 | if (s->dict.size > s->dict.size_max) | ||
1139 | return XZ_MEMLIMIT_ERROR; | ||
1140 | |||
1141 | s->dict.end = s->dict.size; | ||
1142 | |||
1143 | if (DEC_IS_DYNALLOC(s->dict.mode)) { | ||
1144 | if (s->dict.allocated < s->dict.size) { | ||
1145 | vfree(s->dict.buf); | ||
1146 | s->dict.buf = vmalloc(s->dict.size); | ||
1147 | if (s->dict.buf == NULL) { | ||
1148 | s->dict.allocated = 0; | ||
1149 | return XZ_MEM_ERROR; | ||
1150 | } | ||
1151 | } | ||
1152 | } | ||
1153 | } | ||
1154 | |||
1155 | s->lzma.len = 0; | ||
1156 | |||
1157 | s->lzma2.sequence = SEQ_CONTROL; | ||
1158 | s->lzma2.need_dict_reset = true; | ||
1159 | |||
1160 | s->temp.size = 0; | ||
1161 | |||
1162 | return XZ_OK; | ||
1163 | } | ||
1164 | |||
1165 | XZ_EXTERN void xz_dec_lzma2_end(struct xz_dec_lzma2 *s) | ||
1166 | { | ||
1167 | if (DEC_IS_MULTI(s->dict.mode)) | ||
1168 | vfree(s->dict.buf); | ||
1169 | |||
1170 | kfree(s); | ||
1171 | } | ||