xref: /linux/lib/decompress_unlzma.c (revision 40d269c000bda9fcd276a0412a9cebd3f6e344c5)
1 /* Lzma decompressor for Linux kernel. Shamelessly snarfed
2  *from busybox 1.1.1
3  *
4  *Linux kernel adaptation
5  *Copyright (C) 2006  Alain < alain@knaff.lu >
6  *
7  *Based on small lzma deflate implementation/Small range coder
8  *implementation for lzma.
9  *Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
10  *
11  *Based on LzmaDecode.c from the LZMA SDK 4.22 (https://www.7-zip.org/)
12  *Copyright (C) 1999-2005  Igor Pavlov
13  *
14  *Copyrights of the parts, see headers below.
15  *
16  *
17  *This program is free software; you can redistribute it and/or
18  *modify it under the terms of the GNU Lesser General Public
19  *License as published by the Free Software Foundation; either
20  *version 2.1 of the License, or (at your option) any later version.
21  *
22  *This program is distributed in the hope that it will be useful,
23  *but WITHOUT ANY WARRANTY; without even the implied warranty of
24  *MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
25  *Lesser General Public License for more details.
26  *
27  *You should have received a copy of the GNU Lesser General Public
28  *License along with this library; if not, write to the Free Software
29  *Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
30  */
31 
32 #ifdef STATIC
33 #define PREBOOT
34 #else
35 #include <linux/decompress/unlzma.h>
36 #endif /* STATIC */
37 
38 #include <linux/decompress/mm.h>
39 
40 #define	MIN(a, b) (((a) < (b)) ? (a) : (b))
41 
42 static long long INIT read_int(unsigned char *ptr, int size)
43 {
44 	int i;
45 	long long ret = 0;
46 
47 	for (i = 0; i < size; i++)
48 		ret = (ret << 8) | ptr[size-i-1];
49 	return ret;
50 }
51 
52 #define ENDIAN_CONVERT(x) \
53   x = (typeof(x))read_int((unsigned char *)&x, sizeof(x))
54 
55 
56 /* Small range coder implementation for lzma.
57  *Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
58  *
59  *Based on LzmaDecode.c from the LZMA SDK 4.22 (https://www.7-zip.org/)
60  *Copyright (c) 1999-2005  Igor Pavlov
61  */
62 
63 #include <linux/compiler.h>
64 
65 #define LZMA_IOBUF_SIZE	0x10000
66 
67 struct rc {
68 	long (*fill)(void*, unsigned long);
69 	uint8_t *ptr;
70 	uint8_t *buffer;
71 	uint8_t *buffer_end;
72 	long buffer_size;
73 	uint32_t code;
74 	uint32_t range;
75 	uint32_t bound;
76 	void (*error)(char *);
77 };
78 
79 
80 #define RC_TOP_BITS 24
81 #define RC_MOVE_BITS 5
82 #define RC_MODEL_TOTAL_BITS 11
83 
84 
85 static long INIT nofill(void *buffer, unsigned long len)
86 {
87 	return -1;
88 }
89 
90 /* Called twice: once at startup and once in rc_normalize() */
91 static void INIT rc_read(struct rc *rc)
92 {
93 	rc->buffer_size = rc->fill((char *)rc->buffer, LZMA_IOBUF_SIZE);
94 	if (rc->buffer_size <= 0)
95 		rc->error("unexpected EOF");
96 	rc->ptr = rc->buffer;
97 	rc->buffer_end = rc->buffer + rc->buffer_size;
98 }
99 
100 /* Called once */
101 static inline void INIT rc_init(struct rc *rc,
102 				       long (*fill)(void*, unsigned long),
103 				       char *buffer, long buffer_size)
104 {
105 	if (fill)
106 		rc->fill = fill;
107 	else
108 		rc->fill = nofill;
109 	rc->buffer = (uint8_t *)buffer;
110 	rc->buffer_size = buffer_size;
111 	rc->buffer_end = rc->buffer + rc->buffer_size;
112 	rc->ptr = rc->buffer;
113 
114 	rc->code = 0;
115 	rc->range = 0xFFFFFFFF;
116 }
117 
118 static inline void INIT rc_init_code(struct rc *rc)
119 {
120 	int i;
121 
122 	for (i = 0; i < 5; i++) {
123 		if (rc->ptr >= rc->buffer_end)
124 			rc_read(rc);
125 		rc->code = (rc->code << 8) | *rc->ptr++;
126 	}
127 }
128 
129 
130 /* Called twice, but one callsite is in inline'd rc_is_bit_0_helper() */
131 static void INIT rc_do_normalize(struct rc *rc)
132 {
133 	if (rc->ptr >= rc->buffer_end)
134 		rc_read(rc);
135 	rc->range <<= 8;
136 	rc->code = (rc->code << 8) | *rc->ptr++;
137 }
138 static inline void INIT rc_normalize(struct rc *rc)
139 {
140 	if (rc->range < (1 << RC_TOP_BITS))
141 		rc_do_normalize(rc);
142 }
143 
144 /* Called 9 times */
145 /* Why rc_is_bit_0_helper exists?
146  *Because we want to always expose (rc->code < rc->bound) to optimizer
147  */
148 static inline uint32_t INIT rc_is_bit_0_helper(struct rc *rc, uint16_t *p)
149 {
150 	rc_normalize(rc);
151 	rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
152 	return rc->bound;
153 }
154 static inline int INIT rc_is_bit_0(struct rc *rc, uint16_t *p)
155 {
156 	uint32_t t = rc_is_bit_0_helper(rc, p);
157 	return rc->code < t;
158 }
159 
160 /* Called ~10 times, but very small, thus inlined */
161 static inline void INIT rc_update_bit_0(struct rc *rc, uint16_t *p)
162 {
163 	rc->range = rc->bound;
164 	*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
165 }
166 static inline void INIT rc_update_bit_1(struct rc *rc, uint16_t *p)
167 {
168 	rc->range -= rc->bound;
169 	rc->code -= rc->bound;
170 	*p -= *p >> RC_MOVE_BITS;
171 }
172 
173 /* Called 4 times in unlzma loop */
174 static int INIT rc_get_bit(struct rc *rc, uint16_t *p, int *symbol)
175 {
176 	if (rc_is_bit_0(rc, p)) {
177 		rc_update_bit_0(rc, p);
178 		*symbol *= 2;
179 		return 0;
180 	} else {
181 		rc_update_bit_1(rc, p);
182 		*symbol = *symbol * 2 + 1;
183 		return 1;
184 	}
185 }
186 
187 /* Called once */
188 static inline int INIT rc_direct_bit(struct rc *rc)
189 {
190 	rc_normalize(rc);
191 	rc->range >>= 1;
192 	if (rc->code >= rc->range) {
193 		rc->code -= rc->range;
194 		return 1;
195 	}
196 	return 0;
197 }
198 
199 /* Called twice */
200 static inline void INIT
201 rc_bit_tree_decode(struct rc *rc, uint16_t *p, int num_levels, int *symbol)
202 {
203 	int i = num_levels;
204 
205 	*symbol = 1;
206 	while (i--)
207 		rc_get_bit(rc, p + *symbol, symbol);
208 	*symbol -= 1 << num_levels;
209 }
210 
211 
212 /*
213  * Small lzma deflate implementation.
214  * Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
215  *
216  * Based on LzmaDecode.c from the LZMA SDK 4.22 (https://www.7-zip.org/)
217  * Copyright (C) 1999-2005  Igor Pavlov
218  */
219 
220 
221 struct lzma_header {
222 	uint8_t pos;
223 	uint32_t dict_size;
224 	uint64_t dst_size;
225 } __attribute__ ((packed)) ;
226 
227 
228 #define LZMA_BASE_SIZE 1846
229 #define LZMA_LIT_SIZE 768
230 
231 #define LZMA_NUM_POS_BITS_MAX 4
232 
233 #define LZMA_LEN_NUM_LOW_BITS 3
234 #define LZMA_LEN_NUM_MID_BITS 3
235 #define LZMA_LEN_NUM_HIGH_BITS 8
236 
237 #define LZMA_LEN_CHOICE 0
238 #define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
239 #define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
240 #define LZMA_LEN_MID (LZMA_LEN_LOW \
241 		      + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
242 #define LZMA_LEN_HIGH (LZMA_LEN_MID \
243 		       +(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
244 #define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
245 
246 #define LZMA_NUM_STATES 12
247 #define LZMA_NUM_LIT_STATES 7
248 
249 #define LZMA_START_POS_MODEL_INDEX 4
250 #define LZMA_END_POS_MODEL_INDEX 14
251 #define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
252 
253 #define LZMA_NUM_POS_SLOT_BITS 6
254 #define LZMA_NUM_LEN_TO_POS_STATES 4
255 
256 #define LZMA_NUM_ALIGN_BITS 4
257 
258 #define LZMA_MATCH_MIN_LEN 2
259 
260 #define LZMA_IS_MATCH 0
261 #define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
262 #define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
263 #define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
264 #define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
265 #define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
266 #define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
267 		       + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
268 #define LZMA_SPEC_POS (LZMA_POS_SLOT \
269 		       +(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
270 #define LZMA_ALIGN (LZMA_SPEC_POS \
271 		    + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
272 #define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
273 #define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
274 #define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
275 
276 
277 struct writer {
278 	uint8_t *buffer;
279 	uint8_t previous_byte;
280 	size_t buffer_pos;
281 	int bufsize;
282 	size_t global_pos;
283 	long (*flush)(void*, unsigned long);
284 	struct lzma_header *header;
285 };
286 
287 struct cstate {
288 	int state;
289 	uint32_t rep0, rep1, rep2, rep3;
290 };
291 
292 static inline size_t INIT get_pos(struct writer *wr)
293 {
294 	return
295 		wr->global_pos + wr->buffer_pos;
296 }
297 
298 static inline uint8_t INIT peek_old_byte(struct writer *wr,
299 						uint32_t offs)
300 {
301 	if (!wr->flush) {
302 		int32_t pos;
303 		while (offs > wr->header->dict_size)
304 			offs -= wr->header->dict_size;
305 		pos = wr->buffer_pos - offs;
306 		return wr->buffer[pos];
307 	} else {
308 		uint32_t pos = wr->buffer_pos - offs;
309 		while (pos >= wr->header->dict_size)
310 			pos += wr->header->dict_size;
311 		return wr->buffer[pos];
312 	}
313 
314 }
315 
316 static inline int INIT write_byte(struct writer *wr, uint8_t byte)
317 {
318 	wr->buffer[wr->buffer_pos++] = wr->previous_byte = byte;
319 	if (wr->flush && wr->buffer_pos == wr->header->dict_size) {
320 		wr->buffer_pos = 0;
321 		wr->global_pos += wr->header->dict_size;
322 		if (wr->flush((char *)wr->buffer, wr->header->dict_size)
323 				!= wr->header->dict_size)
324 			return -1;
325 	}
326 	return 0;
327 }
328 
329 
330 static inline int INIT copy_byte(struct writer *wr, uint32_t offs)
331 {
332 	return write_byte(wr, peek_old_byte(wr, offs));
333 }
334 
335 static inline int INIT copy_bytes(struct writer *wr,
336 					 uint32_t rep0, int len)
337 {
338 	do {
339 		if (copy_byte(wr, rep0))
340 			return -1;
341 		len--;
342 	} while (len != 0 && wr->buffer_pos < wr->header->dst_size);
343 
344 	return len;
345 }
346 
347 static inline int INIT process_bit0(struct writer *wr, struct rc *rc,
348 				     struct cstate *cst, uint16_t *p,
349 				     int pos_state, uint16_t *prob,
350 				     int lc, uint32_t literal_pos_mask) {
351 	int mi = 1;
352 	rc_update_bit_0(rc, prob);
353 	prob = (p + LZMA_LITERAL +
354 		(LZMA_LIT_SIZE
355 		 * (((get_pos(wr) & literal_pos_mask) << lc)
356 		    + (wr->previous_byte >> (8 - lc))))
357 		);
358 
359 	if (cst->state >= LZMA_NUM_LIT_STATES) {
360 		int match_byte = peek_old_byte(wr, cst->rep0);
361 		do {
362 			int bit;
363 			uint16_t *prob_lit;
364 
365 			match_byte <<= 1;
366 			bit = match_byte & 0x100;
367 			prob_lit = prob + 0x100 + bit + mi;
368 			if (rc_get_bit(rc, prob_lit, &mi)) {
369 				if (!bit)
370 					break;
371 			} else {
372 				if (bit)
373 					break;
374 			}
375 		} while (mi < 0x100);
376 	}
377 	while (mi < 0x100) {
378 		uint16_t *prob_lit = prob + mi;
379 		rc_get_bit(rc, prob_lit, &mi);
380 	}
381 	if (cst->state < 4)
382 		cst->state = 0;
383 	else if (cst->state < 10)
384 		cst->state -= 3;
385 	else
386 		cst->state -= 6;
387 
388 	return write_byte(wr, mi);
389 }
390 
391 static inline int INIT process_bit1(struct writer *wr, struct rc *rc,
392 					    struct cstate *cst, uint16_t *p,
393 					    int pos_state, uint16_t *prob) {
394 	int offset;
395 	uint16_t *prob_len;
396 	int num_bits;
397 	int len;
398 
399 	rc_update_bit_1(rc, prob);
400 	prob = p + LZMA_IS_REP + cst->state;
401 	if (rc_is_bit_0(rc, prob)) {
402 		rc_update_bit_0(rc, prob);
403 		cst->rep3 = cst->rep2;
404 		cst->rep2 = cst->rep1;
405 		cst->rep1 = cst->rep0;
406 		cst->state = cst->state < LZMA_NUM_LIT_STATES ? 0 : 3;
407 		prob = p + LZMA_LEN_CODER;
408 	} else {
409 		rc_update_bit_1(rc, prob);
410 		prob = p + LZMA_IS_REP_G0 + cst->state;
411 		if (rc_is_bit_0(rc, prob)) {
412 			rc_update_bit_0(rc, prob);
413 			prob = (p + LZMA_IS_REP_0_LONG
414 				+ (cst->state <<
415 				   LZMA_NUM_POS_BITS_MAX) +
416 				pos_state);
417 			if (rc_is_bit_0(rc, prob)) {
418 				rc_update_bit_0(rc, prob);
419 
420 				cst->state = cst->state < LZMA_NUM_LIT_STATES ?
421 					9 : 11;
422 				return copy_byte(wr, cst->rep0);
423 			} else {
424 				rc_update_bit_1(rc, prob);
425 			}
426 		} else {
427 			uint32_t distance;
428 
429 			rc_update_bit_1(rc, prob);
430 			prob = p + LZMA_IS_REP_G1 + cst->state;
431 			if (rc_is_bit_0(rc, prob)) {
432 				rc_update_bit_0(rc, prob);
433 				distance = cst->rep1;
434 			} else {
435 				rc_update_bit_1(rc, prob);
436 				prob = p + LZMA_IS_REP_G2 + cst->state;
437 				if (rc_is_bit_0(rc, prob)) {
438 					rc_update_bit_0(rc, prob);
439 					distance = cst->rep2;
440 				} else {
441 					rc_update_bit_1(rc, prob);
442 					distance = cst->rep3;
443 					cst->rep3 = cst->rep2;
444 				}
445 				cst->rep2 = cst->rep1;
446 			}
447 			cst->rep1 = cst->rep0;
448 			cst->rep0 = distance;
449 		}
450 		cst->state = cst->state < LZMA_NUM_LIT_STATES ? 8 : 11;
451 		prob = p + LZMA_REP_LEN_CODER;
452 	}
453 
454 	prob_len = prob + LZMA_LEN_CHOICE;
455 	if (rc_is_bit_0(rc, prob_len)) {
456 		rc_update_bit_0(rc, prob_len);
457 		prob_len = (prob + LZMA_LEN_LOW
458 			    + (pos_state <<
459 			       LZMA_LEN_NUM_LOW_BITS));
460 		offset = 0;
461 		num_bits = LZMA_LEN_NUM_LOW_BITS;
462 	} else {
463 		rc_update_bit_1(rc, prob_len);
464 		prob_len = prob + LZMA_LEN_CHOICE_2;
465 		if (rc_is_bit_0(rc, prob_len)) {
466 			rc_update_bit_0(rc, prob_len);
467 			prob_len = (prob + LZMA_LEN_MID
468 				    + (pos_state <<
469 				       LZMA_LEN_NUM_MID_BITS));
470 			offset = 1 << LZMA_LEN_NUM_LOW_BITS;
471 			num_bits = LZMA_LEN_NUM_MID_BITS;
472 		} else {
473 			rc_update_bit_1(rc, prob_len);
474 			prob_len = prob + LZMA_LEN_HIGH;
475 			offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
476 				  + (1 << LZMA_LEN_NUM_MID_BITS));
477 			num_bits = LZMA_LEN_NUM_HIGH_BITS;
478 		}
479 	}
480 
481 	rc_bit_tree_decode(rc, prob_len, num_bits, &len);
482 	len += offset;
483 
484 	if (cst->state < 4) {
485 		int pos_slot;
486 
487 		cst->state += LZMA_NUM_LIT_STATES;
488 		prob =
489 			p + LZMA_POS_SLOT +
490 			((len <
491 			  LZMA_NUM_LEN_TO_POS_STATES ? len :
492 			  LZMA_NUM_LEN_TO_POS_STATES - 1)
493 			 << LZMA_NUM_POS_SLOT_BITS);
494 		rc_bit_tree_decode(rc, prob,
495 				   LZMA_NUM_POS_SLOT_BITS,
496 				   &pos_slot);
497 		if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
498 			int i, mi;
499 			num_bits = (pos_slot >> 1) - 1;
500 			cst->rep0 = 2 | (pos_slot & 1);
501 			if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
502 				cst->rep0 <<= num_bits;
503 				prob = p + LZMA_SPEC_POS +
504 					cst->rep0 - pos_slot - 1;
505 			} else {
506 				num_bits -= LZMA_NUM_ALIGN_BITS;
507 				while (num_bits--)
508 					cst->rep0 = (cst->rep0 << 1) |
509 						rc_direct_bit(rc);
510 				prob = p + LZMA_ALIGN;
511 				cst->rep0 <<= LZMA_NUM_ALIGN_BITS;
512 				num_bits = LZMA_NUM_ALIGN_BITS;
513 			}
514 			i = 1;
515 			mi = 1;
516 			while (num_bits--) {
517 				if (rc_get_bit(rc, prob + mi, &mi))
518 					cst->rep0 |= i;
519 				i <<= 1;
520 			}
521 		} else
522 			cst->rep0 = pos_slot;
523 		if (++(cst->rep0) == 0)
524 			return 0;
525 		if (cst->rep0 > wr->header->dict_size
526 				|| cst->rep0 > get_pos(wr))
527 			return -1;
528 	}
529 
530 	len += LZMA_MATCH_MIN_LEN;
531 
532 	return copy_bytes(wr, cst->rep0, len);
533 }
534 
535 
536 
537 STATIC inline int INIT unlzma(unsigned char *buf, long in_len,
538 			      long (*fill)(void*, unsigned long),
539 			      long (*flush)(void*, unsigned long),
540 			      unsigned char *output,
541 			      long *posp,
542 			      void(*error)(char *x)
543 	)
544 {
545 	struct lzma_header header;
546 	int lc, pb, lp;
547 	uint32_t pos_state_mask;
548 	uint32_t literal_pos_mask;
549 	uint16_t *p;
550 	int num_probs;
551 	struct rc rc;
552 	int i, mi;
553 	struct writer wr;
554 	struct cstate cst;
555 	unsigned char *inbuf;
556 	int ret = -1;
557 
558 	rc.error = error;
559 
560 	if (buf)
561 		inbuf = buf;
562 	else
563 		inbuf = malloc(LZMA_IOBUF_SIZE);
564 	if (!inbuf) {
565 		error("Could not allocate input buffer");
566 		goto exit_0;
567 	}
568 
569 	cst.state = 0;
570 	cst.rep0 = cst.rep1 = cst.rep2 = cst.rep3 = 1;
571 
572 	wr.header = &header;
573 	wr.flush = flush;
574 	wr.global_pos = 0;
575 	wr.previous_byte = 0;
576 	wr.buffer_pos = 0;
577 
578 	rc_init(&rc, fill, inbuf, in_len);
579 
580 	for (i = 0; i < sizeof(header); i++) {
581 		if (rc.ptr >= rc.buffer_end)
582 			rc_read(&rc);
583 		((unsigned char *)&header)[i] = *rc.ptr++;
584 	}
585 
586 	if (header.pos >= (9 * 5 * 5)) {
587 		error("bad header");
588 		goto exit_1;
589 	}
590 
591 	mi = 0;
592 	lc = header.pos;
593 	while (lc >= 9) {
594 		mi++;
595 		lc -= 9;
596 	}
597 	pb = 0;
598 	lp = mi;
599 	while (lp >= 5) {
600 		pb++;
601 		lp -= 5;
602 	}
603 	pos_state_mask = (1 << pb) - 1;
604 	literal_pos_mask = (1 << lp) - 1;
605 
606 	ENDIAN_CONVERT(header.dict_size);
607 	ENDIAN_CONVERT(header.dst_size);
608 
609 	if (header.dict_size == 0)
610 		header.dict_size = 1;
611 
612 	if (output)
613 		wr.buffer = output;
614 	else {
615 		wr.bufsize = MIN(header.dst_size, header.dict_size);
616 		wr.buffer = large_malloc(wr.bufsize);
617 	}
618 	if (wr.buffer == NULL)
619 		goto exit_1;
620 
621 	num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
622 	p = (uint16_t *) large_malloc(num_probs * sizeof(*p));
623 	if (p == NULL)
624 		goto exit_2;
625 	num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
626 	for (i = 0; i < num_probs; i++)
627 		p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
628 
629 	rc_init_code(&rc);
630 
631 	while (get_pos(&wr) < header.dst_size) {
632 		int pos_state =	get_pos(&wr) & pos_state_mask;
633 		uint16_t *prob = p + LZMA_IS_MATCH +
634 			(cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state;
635 		if (rc_is_bit_0(&rc, prob)) {
636 			if (process_bit0(&wr, &rc, &cst, p, pos_state, prob,
637 					lc, literal_pos_mask)) {
638 				error("LZMA data is corrupt");
639 				goto exit_3;
640 			}
641 		} else {
642 			if (process_bit1(&wr, &rc, &cst, p, pos_state, prob)) {
643 				error("LZMA data is corrupt");
644 				goto exit_3;
645 			}
646 			if (cst.rep0 == 0)
647 				break;
648 		}
649 		if (rc.buffer_size <= 0)
650 			goto exit_3;
651 	}
652 
653 	if (posp)
654 		*posp = rc.ptr-rc.buffer;
655 	if (!wr.flush || wr.flush(wr.buffer, wr.buffer_pos) == wr.buffer_pos)
656 		ret = 0;
657 exit_3:
658 	large_free(p);
659 exit_2:
660 	if (!output)
661 		large_free(wr.buffer);
662 exit_1:
663 	if (!buf)
664 		free(inbuf);
665 exit_0:
666 	return ret;
667 }
668 
669 #ifdef PREBOOT
670 STATIC int INIT __decompress(unsigned char *buf, long in_len,
671 			      long (*fill)(void*, unsigned long),
672 			      long (*flush)(void*, unsigned long),
673 			      unsigned char *output, long out_len,
674 			      long *posp,
675 			      void (*error)(char *x))
676 {
677 	return unlzma(buf, in_len - 4, fill, flush, output, posp, error);
678 }
679 #endif
680