xref: /linux/lib/decompress_unlzma.c (revision d8b762070c3fde224f8b9ea3cf59bc41a5a3eb57)
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 #ifndef MIN
41 #define	MIN(a, b) (((a) < (b)) ? (a) : (b))
42 #endif
43 
44 static long long INIT read_int(unsigned char *ptr, int size)
45 {
46 	int i;
47 	long long ret = 0;
48 
49 	for (i = 0; i < size; i++)
50 		ret = (ret << 8) | ptr[size-i-1];
51 	return ret;
52 }
53 
54 #define ENDIAN_CONVERT(x) \
55   x = (typeof(x))read_int((unsigned char *)&x, sizeof(x))
56 
57 
58 /* Small range coder implementation for lzma.
59  *Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
60  *
61  *Based on LzmaDecode.c from the LZMA SDK 4.22 (https://www.7-zip.org/)
62  *Copyright (c) 1999-2005  Igor Pavlov
63  */
64 
65 #include <linux/compiler.h>
66 
67 #define LZMA_IOBUF_SIZE	0x10000
68 
69 struct rc {
70 	long (*fill)(void*, unsigned long);
71 	uint8_t *ptr;
72 	uint8_t *buffer;
73 	uint8_t *buffer_end;
74 	long buffer_size;
75 	uint32_t code;
76 	uint32_t range;
77 	uint32_t bound;
78 	void (*error)(char *);
79 };
80 
81 
82 #define RC_TOP_BITS 24
83 #define RC_MOVE_BITS 5
84 #define RC_MODEL_TOTAL_BITS 11
85 
86 
87 static long INIT nofill(void *buffer, unsigned long len)
88 {
89 	return -1;
90 }
91 
92 /* Called twice: once at startup and once in rc_normalize() */
93 static void INIT rc_read(struct rc *rc)
94 {
95 	rc->buffer_size = rc->fill((char *)rc->buffer, LZMA_IOBUF_SIZE);
96 	if (rc->buffer_size <= 0)
97 		rc->error("unexpected EOF");
98 	rc->ptr = rc->buffer;
99 	rc->buffer_end = rc->buffer + rc->buffer_size;
100 }
101 
102 /* Called once */
103 static inline void INIT rc_init(struct rc *rc,
104 				       long (*fill)(void*, unsigned long),
105 				       char *buffer, long buffer_size)
106 {
107 	if (fill)
108 		rc->fill = fill;
109 	else
110 		rc->fill = nofill;
111 	rc->buffer = (uint8_t *)buffer;
112 	rc->buffer_size = buffer_size;
113 	rc->buffer_end = rc->buffer + rc->buffer_size;
114 	rc->ptr = rc->buffer;
115 
116 	rc->code = 0;
117 	rc->range = 0xFFFFFFFF;
118 }
119 
120 static inline void INIT rc_init_code(struct rc *rc)
121 {
122 	int i;
123 
124 	for (i = 0; i < 5; i++) {
125 		if (rc->ptr >= rc->buffer_end)
126 			rc_read(rc);
127 		rc->code = (rc->code << 8) | *rc->ptr++;
128 	}
129 }
130 
131 
132 /* Called twice, but one callsite is in inline'd rc_is_bit_0_helper() */
133 static void INIT rc_do_normalize(struct rc *rc)
134 {
135 	if (rc->ptr >= rc->buffer_end)
136 		rc_read(rc);
137 	rc->range <<= 8;
138 	rc->code = (rc->code << 8) | *rc->ptr++;
139 }
140 static inline void INIT rc_normalize(struct rc *rc)
141 {
142 	if (rc->range < (1 << RC_TOP_BITS))
143 		rc_do_normalize(rc);
144 }
145 
146 /* Called 9 times */
147 /* Why rc_is_bit_0_helper exists?
148  *Because we want to always expose (rc->code < rc->bound) to optimizer
149  */
150 static inline uint32_t INIT rc_is_bit_0_helper(struct rc *rc, uint16_t *p)
151 {
152 	rc_normalize(rc);
153 	rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
154 	return rc->bound;
155 }
156 static inline int INIT rc_is_bit_0(struct rc *rc, uint16_t *p)
157 {
158 	uint32_t t = rc_is_bit_0_helper(rc, p);
159 	return rc->code < t;
160 }
161 
162 /* Called ~10 times, but very small, thus inlined */
163 static inline void INIT rc_update_bit_0(struct rc *rc, uint16_t *p)
164 {
165 	rc->range = rc->bound;
166 	*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
167 }
168 static inline void INIT rc_update_bit_1(struct rc *rc, uint16_t *p)
169 {
170 	rc->range -= rc->bound;
171 	rc->code -= rc->bound;
172 	*p -= *p >> RC_MOVE_BITS;
173 }
174 
175 /* Called 4 times in unlzma loop */
176 static int INIT rc_get_bit(struct rc *rc, uint16_t *p, int *symbol)
177 {
178 	if (rc_is_bit_0(rc, p)) {
179 		rc_update_bit_0(rc, p);
180 		*symbol *= 2;
181 		return 0;
182 	} else {
183 		rc_update_bit_1(rc, p);
184 		*symbol = *symbol * 2 + 1;
185 		return 1;
186 	}
187 }
188 
189 /* Called once */
190 static inline int INIT rc_direct_bit(struct rc *rc)
191 {
192 	rc_normalize(rc);
193 	rc->range >>= 1;
194 	if (rc->code >= rc->range) {
195 		rc->code -= rc->range;
196 		return 1;
197 	}
198 	return 0;
199 }
200 
201 /* Called twice */
202 static inline void INIT
203 rc_bit_tree_decode(struct rc *rc, uint16_t *p, int num_levels, int *symbol)
204 {
205 	int i = num_levels;
206 
207 	*symbol = 1;
208 	while (i--)
209 		rc_get_bit(rc, p + *symbol, symbol);
210 	*symbol -= 1 << num_levels;
211 }
212 
213 
214 /*
215  * Small lzma deflate implementation.
216  * Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
217  *
218  * Based on LzmaDecode.c from the LZMA SDK 4.22 (https://www.7-zip.org/)
219  * Copyright (C) 1999-2005  Igor Pavlov
220  */
221 
222 
223 struct lzma_header {
224 	uint8_t pos;
225 	uint32_t dict_size;
226 	uint64_t dst_size;
227 } __attribute__ ((packed)) ;
228 
229 
230 #define LZMA_BASE_SIZE 1846
231 #define LZMA_LIT_SIZE 768
232 
233 #define LZMA_NUM_POS_BITS_MAX 4
234 
235 #define LZMA_LEN_NUM_LOW_BITS 3
236 #define LZMA_LEN_NUM_MID_BITS 3
237 #define LZMA_LEN_NUM_HIGH_BITS 8
238 
239 #define LZMA_LEN_CHOICE 0
240 #define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
241 #define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
242 #define LZMA_LEN_MID (LZMA_LEN_LOW \
243 		      + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
244 #define LZMA_LEN_HIGH (LZMA_LEN_MID \
245 		       +(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
246 #define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
247 
248 #define LZMA_NUM_STATES 12
249 #define LZMA_NUM_LIT_STATES 7
250 
251 #define LZMA_START_POS_MODEL_INDEX 4
252 #define LZMA_END_POS_MODEL_INDEX 14
253 #define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
254 
255 #define LZMA_NUM_POS_SLOT_BITS 6
256 #define LZMA_NUM_LEN_TO_POS_STATES 4
257 
258 #define LZMA_NUM_ALIGN_BITS 4
259 
260 #define LZMA_MATCH_MIN_LEN 2
261 
262 #define LZMA_IS_MATCH 0
263 #define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
264 #define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
265 #define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
266 #define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
267 #define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
268 #define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
269 		       + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
270 #define LZMA_SPEC_POS (LZMA_POS_SLOT \
271 		       +(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
272 #define LZMA_ALIGN (LZMA_SPEC_POS \
273 		    + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
274 #define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
275 #define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
276 #define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
277 
278 
279 struct writer {
280 	uint8_t *buffer;
281 	uint8_t previous_byte;
282 	size_t buffer_pos;
283 	int bufsize;
284 	size_t global_pos;
285 	long (*flush)(void*, unsigned long);
286 	struct lzma_header *header;
287 };
288 
289 struct cstate {
290 	int state;
291 	uint32_t rep0, rep1, rep2, rep3;
292 };
293 
294 static inline size_t INIT get_pos(struct writer *wr)
295 {
296 	return
297 		wr->global_pos + wr->buffer_pos;
298 }
299 
300 static inline uint8_t INIT peek_old_byte(struct writer *wr,
301 						uint32_t offs)
302 {
303 	if (!wr->flush) {
304 		int32_t pos;
305 		while (offs > wr->header->dict_size)
306 			offs -= wr->header->dict_size;
307 		pos = wr->buffer_pos - offs;
308 		return wr->buffer[pos];
309 	} else {
310 		uint32_t pos = wr->buffer_pos - offs;
311 		while (pos >= wr->header->dict_size)
312 			pos += wr->header->dict_size;
313 		return wr->buffer[pos];
314 	}
315 
316 }
317 
318 static inline int INIT write_byte(struct writer *wr, uint8_t byte)
319 {
320 	wr->buffer[wr->buffer_pos++] = wr->previous_byte = byte;
321 	if (wr->flush && wr->buffer_pos == wr->header->dict_size) {
322 		wr->buffer_pos = 0;
323 		wr->global_pos += wr->header->dict_size;
324 		if (wr->flush((char *)wr->buffer, wr->header->dict_size)
325 				!= wr->header->dict_size)
326 			return -1;
327 	}
328 	return 0;
329 }
330 
331 
332 static inline int INIT copy_byte(struct writer *wr, uint32_t offs)
333 {
334 	return write_byte(wr, peek_old_byte(wr, offs));
335 }
336 
337 static inline int INIT copy_bytes(struct writer *wr,
338 					 uint32_t rep0, int len)
339 {
340 	do {
341 		if (copy_byte(wr, rep0))
342 			return -1;
343 		len--;
344 	} while (len != 0 && wr->buffer_pos < wr->header->dst_size);
345 
346 	return len;
347 }
348 
349 static inline int INIT process_bit0(struct writer *wr, struct rc *rc,
350 				     struct cstate *cst, uint16_t *p,
351 				     int pos_state, uint16_t *prob,
352 				     int lc, uint32_t literal_pos_mask) {
353 	int mi = 1;
354 	rc_update_bit_0(rc, prob);
355 	prob = (p + LZMA_LITERAL +
356 		(LZMA_LIT_SIZE
357 		 * (((get_pos(wr) & literal_pos_mask) << lc)
358 		    + (wr->previous_byte >> (8 - lc))))
359 		);
360 
361 	if (cst->state >= LZMA_NUM_LIT_STATES) {
362 		int match_byte = peek_old_byte(wr, cst->rep0);
363 		do {
364 			int bit;
365 			uint16_t *prob_lit;
366 
367 			match_byte <<= 1;
368 			bit = match_byte & 0x100;
369 			prob_lit = prob + 0x100 + bit + mi;
370 			if (rc_get_bit(rc, prob_lit, &mi)) {
371 				if (!bit)
372 					break;
373 			} else {
374 				if (bit)
375 					break;
376 			}
377 		} while (mi < 0x100);
378 	}
379 	while (mi < 0x100) {
380 		uint16_t *prob_lit = prob + mi;
381 		rc_get_bit(rc, prob_lit, &mi);
382 	}
383 	if (cst->state < 4)
384 		cst->state = 0;
385 	else if (cst->state < 10)
386 		cst->state -= 3;
387 	else
388 		cst->state -= 6;
389 
390 	return write_byte(wr, mi);
391 }
392 
393 static inline int INIT process_bit1(struct writer *wr, struct rc *rc,
394 					    struct cstate *cst, uint16_t *p,
395 					    int pos_state, uint16_t *prob) {
396 	int offset;
397 	uint16_t *prob_len;
398 	int num_bits;
399 	int len;
400 
401 	rc_update_bit_1(rc, prob);
402 	prob = p + LZMA_IS_REP + cst->state;
403 	if (rc_is_bit_0(rc, prob)) {
404 		rc_update_bit_0(rc, prob);
405 		cst->rep3 = cst->rep2;
406 		cst->rep2 = cst->rep1;
407 		cst->rep1 = cst->rep0;
408 		cst->state = cst->state < LZMA_NUM_LIT_STATES ? 0 : 3;
409 		prob = p + LZMA_LEN_CODER;
410 	} else {
411 		rc_update_bit_1(rc, prob);
412 		prob = p + LZMA_IS_REP_G0 + cst->state;
413 		if (rc_is_bit_0(rc, prob)) {
414 			rc_update_bit_0(rc, prob);
415 			prob = (p + LZMA_IS_REP_0_LONG
416 				+ (cst->state <<
417 				   LZMA_NUM_POS_BITS_MAX) +
418 				pos_state);
419 			if (rc_is_bit_0(rc, prob)) {
420 				rc_update_bit_0(rc, prob);
421 
422 				cst->state = cst->state < LZMA_NUM_LIT_STATES ?
423 					9 : 11;
424 				return copy_byte(wr, cst->rep0);
425 			} else {
426 				rc_update_bit_1(rc, prob);
427 			}
428 		} else {
429 			uint32_t distance;
430 
431 			rc_update_bit_1(rc, prob);
432 			prob = p + LZMA_IS_REP_G1 + cst->state;
433 			if (rc_is_bit_0(rc, prob)) {
434 				rc_update_bit_0(rc, prob);
435 				distance = cst->rep1;
436 			} else {
437 				rc_update_bit_1(rc, prob);
438 				prob = p + LZMA_IS_REP_G2 + cst->state;
439 				if (rc_is_bit_0(rc, prob)) {
440 					rc_update_bit_0(rc, prob);
441 					distance = cst->rep2;
442 				} else {
443 					rc_update_bit_1(rc, prob);
444 					distance = cst->rep3;
445 					cst->rep3 = cst->rep2;
446 				}
447 				cst->rep2 = cst->rep1;
448 			}
449 			cst->rep1 = cst->rep0;
450 			cst->rep0 = distance;
451 		}
452 		cst->state = cst->state < LZMA_NUM_LIT_STATES ? 8 : 11;
453 		prob = p + LZMA_REP_LEN_CODER;
454 	}
455 
456 	prob_len = prob + LZMA_LEN_CHOICE;
457 	if (rc_is_bit_0(rc, prob_len)) {
458 		rc_update_bit_0(rc, prob_len);
459 		prob_len = (prob + LZMA_LEN_LOW
460 			    + (pos_state <<
461 			       LZMA_LEN_NUM_LOW_BITS));
462 		offset = 0;
463 		num_bits = LZMA_LEN_NUM_LOW_BITS;
464 	} else {
465 		rc_update_bit_1(rc, prob_len);
466 		prob_len = prob + LZMA_LEN_CHOICE_2;
467 		if (rc_is_bit_0(rc, prob_len)) {
468 			rc_update_bit_0(rc, prob_len);
469 			prob_len = (prob + LZMA_LEN_MID
470 				    + (pos_state <<
471 				       LZMA_LEN_NUM_MID_BITS));
472 			offset = 1 << LZMA_LEN_NUM_LOW_BITS;
473 			num_bits = LZMA_LEN_NUM_MID_BITS;
474 		} else {
475 			rc_update_bit_1(rc, prob_len);
476 			prob_len = prob + LZMA_LEN_HIGH;
477 			offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
478 				  + (1 << LZMA_LEN_NUM_MID_BITS));
479 			num_bits = LZMA_LEN_NUM_HIGH_BITS;
480 		}
481 	}
482 
483 	rc_bit_tree_decode(rc, prob_len, num_bits, &len);
484 	len += offset;
485 
486 	if (cst->state < 4) {
487 		int pos_slot;
488 
489 		cst->state += LZMA_NUM_LIT_STATES;
490 		prob =
491 			p + LZMA_POS_SLOT +
492 			((len <
493 			  LZMA_NUM_LEN_TO_POS_STATES ? len :
494 			  LZMA_NUM_LEN_TO_POS_STATES - 1)
495 			 << LZMA_NUM_POS_SLOT_BITS);
496 		rc_bit_tree_decode(rc, prob,
497 				   LZMA_NUM_POS_SLOT_BITS,
498 				   &pos_slot);
499 		if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
500 			int i, mi;
501 			num_bits = (pos_slot >> 1) - 1;
502 			cst->rep0 = 2 | (pos_slot & 1);
503 			if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
504 				cst->rep0 <<= num_bits;
505 				prob = p + LZMA_SPEC_POS +
506 					cst->rep0 - pos_slot - 1;
507 			} else {
508 				num_bits -= LZMA_NUM_ALIGN_BITS;
509 				while (num_bits--)
510 					cst->rep0 = (cst->rep0 << 1) |
511 						rc_direct_bit(rc);
512 				prob = p + LZMA_ALIGN;
513 				cst->rep0 <<= LZMA_NUM_ALIGN_BITS;
514 				num_bits = LZMA_NUM_ALIGN_BITS;
515 			}
516 			i = 1;
517 			mi = 1;
518 			while (num_bits--) {
519 				if (rc_get_bit(rc, prob + mi, &mi))
520 					cst->rep0 |= i;
521 				i <<= 1;
522 			}
523 		} else
524 			cst->rep0 = pos_slot;
525 		if (++(cst->rep0) == 0)
526 			return 0;
527 		if (cst->rep0 > wr->header->dict_size
528 				|| cst->rep0 > get_pos(wr))
529 			return -1;
530 	}
531 
532 	len += LZMA_MATCH_MIN_LEN;
533 
534 	return copy_bytes(wr, cst->rep0, len);
535 }
536 
537 
538 
539 STATIC inline int INIT unlzma(unsigned char *buf, long in_len,
540 			      long (*fill)(void*, unsigned long),
541 			      long (*flush)(void*, unsigned long),
542 			      unsigned char *output,
543 			      long *posp,
544 			      void(*error)(char *x)
545 	)
546 {
547 	struct lzma_header header;
548 	int lc, pb, lp;
549 	uint32_t pos_state_mask;
550 	uint32_t literal_pos_mask;
551 	uint16_t *p;
552 	int num_probs;
553 	struct rc rc;
554 	int i, mi;
555 	struct writer wr;
556 	struct cstate cst;
557 	unsigned char *inbuf;
558 	int ret = -1;
559 
560 	rc.error = error;
561 
562 	if (buf)
563 		inbuf = buf;
564 	else
565 		inbuf = malloc(LZMA_IOBUF_SIZE);
566 	if (!inbuf) {
567 		error("Could not allocate input buffer");
568 		goto exit_0;
569 	}
570 
571 	cst.state = 0;
572 	cst.rep0 = cst.rep1 = cst.rep2 = cst.rep3 = 1;
573 
574 	wr.header = &header;
575 	wr.flush = flush;
576 	wr.global_pos = 0;
577 	wr.previous_byte = 0;
578 	wr.buffer_pos = 0;
579 
580 	rc_init(&rc, fill, inbuf, in_len);
581 
582 	for (i = 0; i < sizeof(header); i++) {
583 		if (rc.ptr >= rc.buffer_end)
584 			rc_read(&rc);
585 		((unsigned char *)&header)[i] = *rc.ptr++;
586 	}
587 
588 	if (header.pos >= (9 * 5 * 5)) {
589 		error("bad header");
590 		goto exit_1;
591 	}
592 
593 	mi = 0;
594 	lc = header.pos;
595 	while (lc >= 9) {
596 		mi++;
597 		lc -= 9;
598 	}
599 	pb = 0;
600 	lp = mi;
601 	while (lp >= 5) {
602 		pb++;
603 		lp -= 5;
604 	}
605 	pos_state_mask = (1 << pb) - 1;
606 	literal_pos_mask = (1 << lp) - 1;
607 
608 	ENDIAN_CONVERT(header.dict_size);
609 	ENDIAN_CONVERT(header.dst_size);
610 
611 	if (header.dict_size == 0)
612 		header.dict_size = 1;
613 
614 	if (output)
615 		wr.buffer = output;
616 	else {
617 		wr.bufsize = MIN(header.dst_size, header.dict_size);
618 		wr.buffer = large_malloc(wr.bufsize);
619 	}
620 	if (wr.buffer == NULL)
621 		goto exit_1;
622 
623 	num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
624 	p = (uint16_t *) large_malloc(num_probs * sizeof(*p));
625 	if (p == NULL)
626 		goto exit_2;
627 	num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
628 	for (i = 0; i < num_probs; i++)
629 		p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
630 
631 	rc_init_code(&rc);
632 
633 	while (get_pos(&wr) < header.dst_size) {
634 		int pos_state =	get_pos(&wr) & pos_state_mask;
635 		uint16_t *prob = p + LZMA_IS_MATCH +
636 			(cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state;
637 		if (rc_is_bit_0(&rc, prob)) {
638 			if (process_bit0(&wr, &rc, &cst, p, pos_state, prob,
639 					lc, literal_pos_mask)) {
640 				error("LZMA data is corrupt");
641 				goto exit_3;
642 			}
643 		} else {
644 			if (process_bit1(&wr, &rc, &cst, p, pos_state, prob)) {
645 				error("LZMA data is corrupt");
646 				goto exit_3;
647 			}
648 			if (cst.rep0 == 0)
649 				break;
650 		}
651 		if (rc.buffer_size <= 0)
652 			goto exit_3;
653 	}
654 
655 	if (posp)
656 		*posp = rc.ptr-rc.buffer;
657 	if (!wr.flush || wr.flush(wr.buffer, wr.buffer_pos) == wr.buffer_pos)
658 		ret = 0;
659 exit_3:
660 	large_free(p);
661 exit_2:
662 	if (!output)
663 		large_free(wr.buffer);
664 exit_1:
665 	if (!buf)
666 		free(inbuf);
667 exit_0:
668 	return ret;
669 }
670 
671 #ifdef PREBOOT
672 STATIC int INIT __decompress(unsigned char *buf, long in_len,
673 			      long (*fill)(void*, unsigned long),
674 			      long (*flush)(void*, unsigned long),
675 			      unsigned char *output, long out_len,
676 			      long *posp,
677 			      void (*error)(char *x))
678 {
679 	return unlzma(buf, in_len - 4, fill, flush, output, posp, error);
680 }
681 #endif
682