summaryrefslogtreecommitdiffstats
path: root/lib/decompress_unlzma.c
blob: 0be83af62b884c3dbfa9f29f9630a5ecfd605e2f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
/* Lzma decompressor for Linux kernel. Shamelessly snarfed
 *from busybox 1.1.1
 *
 *Linux kernel adaptation
 *Copyright (C) 2006  Alain < alain@knaff.lu >
 *
 *Based on small lzma deflate implementation/Small range coder
 *implementation for lzma.
 *Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
 *
 *Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
 *Copyright (C) 1999-2005  Igor Pavlov
 *
 *Copyrights of the parts, see headers below.
 *
 *
 *This program is free software; you can redistribute it and/or
 *modify it under the terms of the GNU Lesser General Public
 *License as published by the Free Software Foundation; either
 *version 2.1 of the License, or (at your option) any later version.
 *
 *This program is distributed in the hope that it will be useful,
 *but WITHOUT ANY WARRANTY; without even the implied warranty of
 *MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *Lesser General Public License for more details.
 *
 *You should have received a copy of the GNU Lesser General Public
 *License along with this library; if not, write to the Free Software
 *Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifdef STATIC
#define PREBOOT
#else
#include <linux/decompress/unlzma.h>
#endif /* STATIC */

#include <linux/decompress/mm.h>

#define	MIN(a, b) (((a) < (b)) ? (a) : (b))

static long long INIT read_int(unsigned char *ptr, int size)
{
	int i;
	long long ret = 0;

	for (i = 0; i < size; i++)
		ret = (ret << 8) | ptr[size-i-1];
	return ret;
}

#define ENDIAN_CONVERT(x) \
  x = (typeof(x))read_int((unsigned char *)&x, sizeof(x))


/* Small range coder implementation for lzma.
 *Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
 *
 *Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
 *Copyright (c) 1999-2005  Igor Pavlov
 */

#include <linux/compiler.h>

#define LZMA_IOBUF_SIZE	0x10000

struct rc {
	long (*fill)(void*, unsigned long);
	uint8_t *ptr;
	uint8_t *buffer;
	uint8_t *buffer_end;
	long buffer_size;
	uint32_t code;
	uint32_t range;
	uint32_t bound;
	void (*error)(char *);
};


#define RC_TOP_BITS 24
#define RC_MOVE_BITS 5
#define RC_MODEL_TOTAL_BITS 11


static long INIT nofill(void *buffer, unsigned long len)
{
	return -1;
}

/* Called twice: once at startup and once in rc_normalize() */
static void INIT rc_read(struct rc *rc)
{
	rc->buffer_size = rc->fill((char *)rc->buffer, LZMA_IOBUF_SIZE);
	if (rc->buffer_size <= 0)
		rc->error("unexpected EOF");
	rc->ptr = rc->buffer;
	rc->buffer_end = rc->buffer + rc->buffer_size;
}

/* Called once */
static inline void INIT rc_init(struct rc *rc,
				       long (*fill)(void*, unsigned long),
				       char *buffer, long buffer_size)
{
	if (fill)
		rc->fill = fill;
	else
		rc->fill = nofill;
	rc->buffer = (uint8_t *)buffer;
	rc->buffer_size = buffer_size;
	rc->buffer_end = rc->buffer + rc->buffer_size;
	rc->ptr = rc->buffer;

	rc->code = 0;
	rc->range = 0xFFFFFFFF;
}

static inline void INIT rc_init_code(struct rc *rc)
{
	int i;

	for (i = 0; i < 5; i++) {
		if (rc->ptr >= rc->buffer_end)
			rc_read(rc);
		rc->code = (rc->code << 8) | *rc->ptr++;
	}
}


/* Called twice, but one callsite is in inline'd rc_is_bit_0_helper() */
static void INIT rc_do_normalize(struct rc *rc)
{
	if (rc->ptr >= rc->buffer_end)
		rc_read(rc);
	rc->range <<= 8;
	rc->code = (rc->code << 8) | *rc->ptr++;
}
static inline void INIT rc_normalize(struct rc *rc)
{
	if (rc->range < (1 << RC_TOP_BITS))
		rc_do_normalize(rc);
}

/* Called 9 times */
/* Why rc_is_bit_0_helper exists?
 *Because we want to always expose (rc->code < rc->bound) to optimizer
 */
static inline uint32_t INIT rc_is_bit_0_helper(struct rc *rc, uint16_t *p)
{
	rc_normalize(rc);
	rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
	return rc->bound;
}
static inline int INIT rc_is_bit_0(struct rc *rc, uint16_t *p)
{
	uint32_t t = rc_is_bit_0_helper(rc, p);
	return rc->code < t;
}

/* Called ~10 times, but very small, thus inlined */
static inline void INIT rc_update_bit_0(struct rc *rc, uint16_t *p)
{
	rc->range = rc->bound;
	*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
}
static inline void INIT rc_update_bit_1(struct rc *rc, uint16_t *p)
{
	rc->range -= rc->bound;
	rc->code -= rc->bound;
	*p -= *p >> RC_MOVE_BITS;
}

/* Called 4 times in unlzma loop */
static int INIT rc_get_bit(struct rc *rc, uint16_t *p, int *symbol)
{
	if (rc_is_bit_0(rc, p)) {
		rc_update_bit_0(rc, p);
		*symbol *= 2;
		return 0;
	} else {
		rc_update_bit_1(rc, p);
		*symbol = *symbol * 2 + 1;
		return 1;
	}
}

/* Called once */
static inline int INIT rc_direct_bit(struct rc *rc)
{
	rc_normalize(rc);
	rc->range >>= 1;
	if (rc->code >= rc->range) {
		rc->code -= rc->range;
		return 1;
	}
	return 0;
}

/* Called twice */
static inline void INIT
rc_bit_tree_decode(struct rc *rc, uint16_t *p, int num_levels, int *symbol)
{
	int i = num_levels;

	*symbol = 1;
	while (i--)
		rc_get_bit(rc, p + *symbol, symbol);
	*symbol -= 1 << num_levels;
}


/*
 * Small lzma deflate implementation.
 * Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
 *
 * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
 * Copyright (C) 1999-2005  Igor Pavlov
 */


struct lzma_header {
	uint8_t pos;
	uint32_t dict_size;
	uint64_t dst_size;
} __attribute__ ((packed)) ;


#define LZMA_BASE_SIZE 1846
#define LZMA_LIT_SIZE 768

#define LZMA_NUM_POS_BITS_MAX 4

#define LZMA_LEN_NUM_LOW_BITS 3
#define LZMA_LEN_NUM_MID_BITS 3
#define LZMA_LEN_NUM_HIGH_BITS 8

#define LZMA_LEN_CHOICE 0
#define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
#define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
#define LZMA_LEN_MID (LZMA_LEN_LOW \
		      + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
#define LZMA_LEN_HIGH (LZMA_LEN_MID \
		       +(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
#define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))

#define LZMA_NUM_STATES 12
#define LZMA_NUM_LIT_STATES 7

#define LZMA_START_POS_MODEL_INDEX 4
#define LZMA_END_POS_MODEL_INDEX 14
#define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))

#define LZMA_NUM_POS_SLOT_BITS 6
#define LZMA_NUM_LEN_TO_POS_STATES 4

#define LZMA_NUM_ALIGN_BITS 4

#define LZMA_MATCH_MIN_LEN 2

#define LZMA_IS_MATCH 0
#define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
#define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
#define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
#define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
#define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
#define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
		       + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
#define LZMA_SPEC_POS (LZMA_POS_SLOT \
		       +(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
#define LZMA_ALIGN (LZMA_SPEC_POS \
		    + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
#define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
#define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
#define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)


struct writer {
	uint8_t *buffer;
	uint8_t previous_byte;
	size_t buffer_pos;
	int bufsize;
	size_t global_pos;
	long (*flush)(void*, unsigned long);
	struct lzma_header *header;
};

struct cstate {
	int state;
	uint32_t rep0, rep1, rep2, rep3;
};

static inline size_t INIT get_pos(struct writer *wr)
{
	return
		wr->global_pos + wr->buffer_pos;
}

static inline uint8_t INIT peek_old_byte(struct writer *wr,
						uint32_t offs)
{
	if (!wr->flush) {
		int32_t pos;
		while (offs > wr->header->dict_size)
			offs -= wr->header->dict_size;
		pos = wr->buffer_pos - offs;
		return wr->buffer[pos];
	} else {
		uint32_t pos = wr->buffer_pos - offs;
		while (pos >= wr->header->dict_size)
			pos += wr->header->dict_size;
		return wr->buffer[pos];
	}

}

static inline int INIT write_byte(struct writer *wr, uint8_t byte)
{
	wr->buffer[wr->buffer_pos++] = wr->previous_byte = byte;
	if (wr->flush && wr->buffer_pos == wr->header->dict_size) {
		wr->buffer_pos = 0;
		wr->global_pos += wr->header->dict_size;
		if (wr->flush((char *)wr->buffer, wr->header->dict_size)
				!= wr->header->dict_size)
			return -1;
	}
	return 0;
}


static inline int INIT copy_byte(struct writer *wr, uint32_t offs)
{
	return write_byte(wr, peek_old_byte(wr, offs));
}

static inline int INIT copy_bytes(struct writer *wr,
					 uint32_t rep0, int len)
{
	do {
		if (copy_byte(wr, rep0))
			return -1;
		len--;
	} while (len != 0 && wr->buffer_pos < wr->header->dst_size);

	return len;
}

static inline int INIT process_bit0(struct writer *wr, struct rc *rc,
				     struct cstate *cst, uint16_t *p,
				     int pos_state, uint16_t *prob,
				     int lc, uint32_t literal_pos_mask) {
	int mi = 1;
	rc_update_bit_0(rc, prob);
	prob = (p + LZMA_LITERAL +
		(LZMA_LIT_SIZE
		 * (((get_pos(wr) & literal_pos_mask) << lc)
		    + (wr->previous_byte >> (8 - lc))))
		);

	if (cst->state >= LZMA_NUM_LIT_STATES) {
		int match_byte = peek_old_byte(wr, cst->rep0);
		do {
			int bit;
			uint16_t *prob_lit;

			match_byte <<= 1;
			bit = match_byte & 0x100;
			prob_lit = prob + 0x100 + bit + mi;
			if (rc_get_bit(rc, prob_lit, &mi)) {
				if (!bit)
					break;
			} else {
				if (bit)
					break;
			}
		} while (mi < 0x100);
	}
	while (mi < 0x100) {
		uint16_t *prob_lit = prob + mi;
		rc_get_bit(rc, prob_lit, &mi);
	}
	if (cst->state < 4)
		cst->state = 0;
	else if (cst->state < 10)
		cst->state -= 3;
	else
		cst->state -= 6;

	return write_byte(wr, mi);
}

static inline int INIT process_bit1(struct writer *wr, struct rc *rc,
					    struct cstate *cst, uint16_t *p,
					    int pos_state, uint16_t *prob) {
  int offset;
	uint16_t *prob_len;
	int num_bits;
	int len;

	rc_update_bit_1(rc, prob);
	prob = p + LZMA_IS_REP + cst->state;
	if (rc_is_bit_0(rc, prob)) {
		rc_update_bit_0(rc, prob);
		cst->rep3 = cst->rep2;
		cst->rep2 = cst->rep1;
		cst->rep1 = cst->rep0;
		cst->state = cst->state < LZMA_NUM_LIT_STATES ? 0 : 3;
		prob = p + LZMA_LEN_CODER;
	} else {
		rc_update_bit_1(rc, prob);
		prob = p + LZMA_IS_REP_G0 + cst->state;
		if (rc_is_bit_0(rc, prob)) {
			rc_update_bit_0(rc, prob);
			prob = (p + LZMA_IS_REP_0_LONG
				+ (cst->state <<
				   LZMA_NUM_POS_BITS_MAX) +
				pos_state);
			if (rc_is_bit_0(rc, prob)) {
				rc_update_bit_0(rc, prob);

				cst->state = cst->state < LZMA_NUM_LIT_STATES ?
					9 : 11;
				return copy_byte(wr, cst->rep0);
			} else {
				rc_update_bit_1(rc, prob);
			}
		} else {
			uint32_t distance;

			rc_update_bit_1(rc, prob);
			prob = p + LZMA_IS_REP_G1 + cst->state;
			if (rc_is_bit_0(rc, prob)) {
				rc_update_bit_0(rc, prob);
				distance = cst->rep1;
			} else {
				rc_update_bit_1(rc, prob);
				prob = p + LZMA_IS_REP_G2 + cst->state;
				if (rc_is_bit_0(rc, prob)) {
					rc_update_bit_0(rc, prob);
					distance = cst->rep2;
				} else {
					rc_update_bit_1(rc, prob);
					distance = cst->rep3;
					cst->rep3 = cst->rep2;
				}
				cst->rep2 = cst->rep1;
			}
			cst->rep1 = cst->rep0;
			cst->rep0 = distance;
		}
		cst->state = cst->state < LZMA_NUM_LIT_STATES ? 8 : 11;
		prob = p + LZMA_REP_LEN_CODER;
	}

	prob_len = prob + LZMA_LEN_CHOICE;
	if (rc_is_bit_0(rc, prob_len)) {
		rc_update_bit_0(rc, prob_len);
		prob_len = (prob + LZMA_LEN_LOW
			    + (pos_state <<
			       LZMA_LEN_NUM_LOW_BITS));
		offset = 0;
		num_bits = LZMA_LEN_NUM_LOW_BITS;
	} else {
		rc_update_bit_1(rc, prob_len);
		prob_len = prob + LZMA_LEN_CHOICE_2;
		if (rc_is_bit_0(rc, prob_len)) {
			rc_update_bit_0(rc, prob_len);
			prob_len = (prob + LZMA_LEN_MID
				    + (pos_state <<
				       LZMA_LEN_NUM_MID_BITS));
			offset = 1 << LZMA_LEN_NUM_LOW_BITS;
			num_bits = LZMA_LEN_NUM_MID_BITS;
		} else {
			rc_update_bit_1(rc, prob_len);
			prob_len = prob + LZMA_LEN_HIGH;
			offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
				  + (1 << LZMA_LEN_NUM_MID_BITS));
			num_bits = LZMA_LEN_NUM_HIGH_BITS;
		}
	}

	rc_bit_tree_decode(rc, prob_len, num_bits, &len);
	len += offset;

	if (cst->state < 4) {
		int pos_slot;

		cst->state += LZMA_NUM_LIT_STATES;
		prob =
			p + LZMA_POS_SLOT +
			((len <
			  LZMA_NUM_LEN_TO_POS_STATES ? len :
			  LZMA_NUM_LEN_TO_POS_STATES - 1)
			 << LZMA_NUM_POS_SLOT_BITS);
		rc_bit_tree_decode(rc, prob,
				   LZMA_NUM_POS_SLOT_BITS,
				   &pos_slot);
		if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
			int i, mi;
			num_bits = (pos_slot >> 1) - 1;
			cst->rep0 = 2 | (pos_slot & 1);
			if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
				cst->rep0 <<= num_bits;
				prob = p + LZMA_SPEC_POS +
					cst->rep0 - pos_slot - 1;
			} else {
				num_bits -= LZMA_NUM_ALIGN_BITS;
				while (num_bits--)
					cst->rep0 = (cst->rep0 << 1) |
						rc_direct_bit(rc);
				prob = p + LZMA_ALIGN;
				cst->rep0 <<= LZMA_NUM_ALIGN_BITS;
				num_bits = LZMA_NUM_ALIGN_BITS;
			}
			i = 1;
			mi = 1;
			while (num_bits--) {
				if (rc_get_bit(rc, prob + mi, &mi))
					cst->rep0 |= i;
				i <<= 1;
			}
		} else
			cst->rep0 = pos_slot;
		if (++(cst->rep0) == 0)
			return 0;
		if (cst->rep0 > wr->header->dict_size
				|| cst->rep0 > get_pos(wr))
			return -1;
	}

	len += LZMA_MATCH_MIN_LEN;

	return copy_bytes(wr, cst->rep0, len);
}



STATIC inline int INIT unlzma(unsigned char *buf, long in_len,
			      long (*fill)(void*, unsigned long),
			      long (*flush)(void*, unsigned long),
			      unsigned char *output,
			      long *posp,
			      void(*error)(char *x)
	)
{
	struct lzma_header header;
	int lc, pb, lp;
	uint32_t pos_state_mask;
	uint32_t literal_pos_mask;
	uint16_t *p;
	int num_probs;
	struct rc rc;
	int i, mi;
	struct writer wr;
	struct cstate cst;
	unsigned char *inbuf;
	int ret = -1;

	rc.error = error;

	if (buf)
		inbuf = buf;
	else
		inbuf = malloc(LZMA_IOBUF_SIZE);
	if (!inbuf) {
		error("Could not allocate input buffer");
		goto exit_0;
	}

	cst.state = 0;
	cst.rep0 = cst.rep1 = cst.rep2 = cst.rep3 = 1;

	wr.header = &header;
	wr.flush = flush;
	wr.global_pos = 0;
	wr.previous_byte = 0;
	wr.buffer_pos = 0;

	rc_init(&rc, fill, inbuf, in_len);

	for (i = 0; i < sizeof(header); i++) {
		if (rc.ptr >= rc.buffer_end)
			rc_read(&rc);
		((unsigned char *)&header)[i] = *rc.ptr++;
	}

	if (header.pos >= (9 * 5 * 5)) {
		error("bad header");
		goto exit_1;
	}

	mi = 0;
	lc = header.pos;
	while (lc >= 9) {
		mi++;
		lc -= 9;
	}
	pb = 0;
	lp = mi;
	while (lp >= 5) {
		pb++;
		lp -= 5;
	}
	pos_state_mask = (1 << pb) - 1;
	literal_pos_mask = (1 << lp) - 1;

	ENDIAN_CONVERT(header.dict_size);
	ENDIAN_CONVERT(header.dst_size);

	if (header.dict_size == 0)
		header.dict_size = 1;

	if (output)
		wr.buffer = output;
	else {
		wr.bufsize = MIN(header.dst_size, header.dict_size);
		wr.buffer = large_malloc(wr.bufsize);
	}
	if (wr.buffer == NULL)
		goto exit_1;

	num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
	p = (uint16_t *) large_malloc(num_probs * sizeof(*p));
	if (p == 0)
		goto exit_2;
	num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
	for (i = 0; i < num_probs; i++)
		p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;

	rc_init_code(&rc);

	while (get_pos(&wr) < header.dst_size) {
		int pos_state =	get_pos(&wr) & pos_state_mask;
		uint16_t *prob = p + LZMA_IS_MATCH +
			(cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state;
		if (rc_is_bit_0(&rc, prob)) {
			if (process_bit0(&wr, &rc, &cst, p, pos_state, prob,
					lc, literal_pos_mask)) {
				error("LZMA data is corrupt");
				goto exit_3;
			}
		} else {
			if (process_bit1(&wr, &rc, &cst, p, pos_state, prob)) {
				error("LZMA data is corrupt");
				goto exit_3;
			}
			if (cst.rep0 == 0)
				break;
		}
		if (rc.buffer_size <= 0)
			goto exit_3;
	}

	if (posp)
		*posp = rc.ptr-rc.buffer;
	if (!wr.flush || wr.flush(wr.buffer, wr.buffer_pos) == wr.buffer_pos)
		ret = 0;
exit_3:
	large_free(p);
exit_2:
	if (!output)
		large_free(wr.buffer);
exit_1:
	if (!buf)
		free(inbuf);
exit_0:
	return ret;
}

#ifdef PREBOOT
STATIC int INIT decompress(unsigned char *buf, long in_len,
			      long (*fill)(void*, unsigned long),
			      long (*flush)(void*, unsigned long),
			      unsigned char *output,
			      long *posp,
			      void(*error)(char *x)
	)
{
	return unlzma(buf, in_len - 4, fill, flush, output, posp, error);
}
#endif