Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
[linux-2.6.git] / lib / decompress_unlzma.c
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 (http://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 #include <linux/slab.h>
37 #endif /* STATIC */
38
39 #include <linux/decompress/mm.h>
40
41 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
42
43 static long long INIT read_int(unsigned char *ptr, int size)
44 {
45         int i;
46         long long ret = 0;
47
48         for (i = 0; i < size; i++)
49                 ret = (ret << 8) | ptr[size-i-1];
50         return ret;
51 }
52
53 #define ENDIAN_CONVERT(x) \
54   x = (typeof(x))read_int((unsigned char *)&x, sizeof(x))
55
56
57 /* Small range coder implementation for lzma.
58  *Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
59  *
60  *Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
61  *Copyright (c) 1999-2005  Igor Pavlov
62  */
63
64 #include <linux/compiler.h>
65
66 #define LZMA_IOBUF_SIZE 0x10000
67
68 struct rc {
69         int (*fill)(void*, unsigned int);
70         uint8_t *ptr;
71         uint8_t *buffer;
72         uint8_t *buffer_end;
73         int buffer_size;
74         uint32_t code;
75         uint32_t range;
76         uint32_t bound;
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 /* Called twice: once at startup and once in rc_normalize() */
86 static void INIT rc_read(struct rc *rc)
87 {
88         rc->buffer_size = rc->fill((char *)rc->buffer, LZMA_IOBUF_SIZE);
89         if (rc->buffer_size <= 0)
90                 error("unexpected EOF");
91         rc->ptr = rc->buffer;
92         rc->buffer_end = rc->buffer + rc->buffer_size;
93 }
94
95 /* Called once */
96 static inline void INIT rc_init(struct rc *rc,
97                                        int (*fill)(void*, unsigned int),
98                                        char *buffer, int buffer_size)
99 {
100         rc->fill = fill;
101         rc->buffer = (uint8_t *)buffer;
102         rc->buffer_size = buffer_size;
103         rc->buffer_end = rc->buffer + rc->buffer_size;
104         rc->ptr = rc->buffer;
105
106         rc->code = 0;
107         rc->range = 0xFFFFFFFF;
108 }
109
110 static inline void INIT rc_init_code(struct rc *rc)
111 {
112         int i;
113
114         for (i = 0; i < 5; i++) {
115                 if (rc->ptr >= rc->buffer_end)
116                         rc_read(rc);
117                 rc->code = (rc->code << 8) | *rc->ptr++;
118         }
119 }
120
121
122 /* Called once. TODO: bb_maybe_free() */
123 static inline void INIT rc_free(struct rc *rc)
124 {
125         free(rc->buffer);
126 }
127
128 /* Called twice, but one callsite is in inline'd rc_is_bit_0_helper() */
129 static void INIT rc_do_normalize(struct rc *rc)
130 {
131         if (rc->ptr >= rc->buffer_end)
132                 rc_read(rc);
133         rc->range <<= 8;
134         rc->code = (rc->code << 8) | *rc->ptr++;
135 }
136 static inline void INIT rc_normalize(struct rc *rc)
137 {
138         if (rc->range < (1 << RC_TOP_BITS))
139                 rc_do_normalize(rc);
140 }
141
142 /* Called 9 times */
143 /* Why rc_is_bit_0_helper exists?
144  *Because we want to always expose (rc->code < rc->bound) to optimizer
145  */
146 static inline uint32_t INIT rc_is_bit_0_helper(struct rc *rc, uint16_t *p)
147 {
148         rc_normalize(rc);
149         rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
150         return rc->bound;
151 }
152 static inline int INIT rc_is_bit_0(struct rc *rc, uint16_t *p)
153 {
154         uint32_t t = rc_is_bit_0_helper(rc, p);
155         return rc->code < t;
156 }
157
158 /* Called ~10 times, but very small, thus inlined */
159 static inline void INIT rc_update_bit_0(struct rc *rc, uint16_t *p)
160 {
161         rc->range = rc->bound;
162         *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
163 }
164 static inline void rc_update_bit_1(struct rc *rc, uint16_t *p)
165 {
166         rc->range -= rc->bound;
167         rc->code -= rc->bound;
168         *p -= *p >> RC_MOVE_BITS;
169 }
170
171 /* Called 4 times in unlzma loop */
172 static int INIT rc_get_bit(struct rc *rc, uint16_t *p, int *symbol)
173 {
174         if (rc_is_bit_0(rc, p)) {
175                 rc_update_bit_0(rc, p);
176                 *symbol *= 2;
177                 return 0;
178         } else {
179                 rc_update_bit_1(rc, p);
180                 *symbol = *symbol * 2 + 1;
181                 return 1;
182         }
183 }
184
185 /* Called once */
186 static inline int INIT rc_direct_bit(struct rc *rc)
187 {
188         rc_normalize(rc);
189         rc->range >>= 1;
190         if (rc->code >= rc->range) {
191                 rc->code -= rc->range;
192                 return 1;
193         }
194         return 0;
195 }
196
197 /* Called twice */
198 static inline void INIT
199 rc_bit_tree_decode(struct rc *rc, uint16_t *p, int num_levels, int *symbol)
200 {
201         int i = num_levels;
202
203         *symbol = 1;
204         while (i--)
205                 rc_get_bit(rc, p + *symbol, symbol);
206         *symbol -= 1 << num_levels;
207 }
208
209
210 /*
211  * Small lzma deflate implementation.
212  * Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
213  *
214  * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
215  * Copyright (C) 1999-2005  Igor Pavlov
216  */
217
218
219 struct lzma_header {
220         uint8_t pos;
221         uint32_t dict_size;
222         uint64_t dst_size;
223 } __attribute__ ((packed)) ;
224
225
226 #define LZMA_BASE_SIZE 1846
227 #define LZMA_LIT_SIZE 768
228
229 #define LZMA_NUM_POS_BITS_MAX 4
230
231 #define LZMA_LEN_NUM_LOW_BITS 3
232 #define LZMA_LEN_NUM_MID_BITS 3
233 #define LZMA_LEN_NUM_HIGH_BITS 8
234
235 #define LZMA_LEN_CHOICE 0
236 #define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
237 #define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
238 #define LZMA_LEN_MID (LZMA_LEN_LOW \
239                       + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
240 #define LZMA_LEN_HIGH (LZMA_LEN_MID \
241                        +(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
242 #define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
243
244 #define LZMA_NUM_STATES 12
245 #define LZMA_NUM_LIT_STATES 7
246
247 #define LZMA_START_POS_MODEL_INDEX 4
248 #define LZMA_END_POS_MODEL_INDEX 14
249 #define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
250
251 #define LZMA_NUM_POS_SLOT_BITS 6
252 #define LZMA_NUM_LEN_TO_POS_STATES 4
253
254 #define LZMA_NUM_ALIGN_BITS 4
255
256 #define LZMA_MATCH_MIN_LEN 2
257
258 #define LZMA_IS_MATCH 0
259 #define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
260 #define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
261 #define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
262 #define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
263 #define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
264 #define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
265                        + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
266 #define LZMA_SPEC_POS (LZMA_POS_SLOT \
267                        +(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
268 #define LZMA_ALIGN (LZMA_SPEC_POS \
269                     + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
270 #define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
271 #define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
272 #define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
273
274
275 struct writer {
276         uint8_t *buffer;
277         uint8_t previous_byte;
278         size_t buffer_pos;
279         int bufsize;
280         size_t global_pos;
281         int(*flush)(void*, unsigned int);
282         struct lzma_header *header;
283 };
284
285 struct cstate {
286         int state;
287         uint32_t rep0, rep1, rep2, rep3;
288 };
289
290 static inline size_t INIT get_pos(struct writer *wr)
291 {
292         return
293                 wr->global_pos + wr->buffer_pos;
294 }
295
296 static inline uint8_t INIT peek_old_byte(struct writer *wr,
297                                                 uint32_t offs)
298 {
299         if (!wr->flush) {
300                 int32_t pos;
301                 while (offs > wr->header->dict_size)
302                         offs -= wr->header->dict_size;
303                 pos = wr->buffer_pos - offs;
304                 return wr->buffer[pos];
305         } else {
306                 uint32_t pos = wr->buffer_pos - offs;
307                 while (pos >= wr->header->dict_size)
308                         pos += wr->header->dict_size;
309                 return wr->buffer[pos];
310         }
311
312 }
313
314 static inline void INIT write_byte(struct writer *wr, uint8_t byte)
315 {
316         wr->buffer[wr->buffer_pos++] = wr->previous_byte = byte;
317         if (wr->flush && wr->buffer_pos == wr->header->dict_size) {
318                 wr->buffer_pos = 0;
319                 wr->global_pos += wr->header->dict_size;
320                 wr->flush((char *)wr->buffer, wr->header->dict_size);
321         }
322 }
323
324
325 static inline void INIT copy_byte(struct writer *wr, uint32_t offs)
326 {
327         write_byte(wr, peek_old_byte(wr, offs));
328 }
329
330 static inline void INIT copy_bytes(struct writer *wr,
331                                          uint32_t rep0, int len)
332 {
333         do {
334                 copy_byte(wr, rep0);
335                 len--;
336         } while (len != 0 && wr->buffer_pos < wr->header->dst_size);
337 }
338
339 static inline void INIT process_bit0(struct writer *wr, struct rc *rc,
340                                      struct cstate *cst, uint16_t *p,
341                                      int pos_state, uint16_t *prob,
342                                      int lc, uint32_t literal_pos_mask) {
343         int mi = 1;
344         rc_update_bit_0(rc, prob);
345         prob = (p + LZMA_LITERAL +
346                 (LZMA_LIT_SIZE
347                  * (((get_pos(wr) & literal_pos_mask) << lc)
348                     + (wr->previous_byte >> (8 - lc))))
349                 );
350
351         if (cst->state >= LZMA_NUM_LIT_STATES) {
352                 int match_byte = peek_old_byte(wr, cst->rep0);
353                 do {
354                         int bit;
355                         uint16_t *prob_lit;
356
357                         match_byte <<= 1;
358                         bit = match_byte & 0x100;
359                         prob_lit = prob + 0x100 + bit + mi;
360                         if (rc_get_bit(rc, prob_lit, &mi)) {
361                                 if (!bit)
362                                         break;
363                         } else {
364                                 if (bit)
365                                         break;
366                         }
367                 } while (mi < 0x100);
368         }
369         while (mi < 0x100) {
370                 uint16_t *prob_lit = prob + mi;
371                 rc_get_bit(rc, prob_lit, &mi);
372         }
373         write_byte(wr, mi);
374         if (cst->state < 4)
375                 cst->state = 0;
376         else if (cst->state < 10)
377                 cst->state -= 3;
378         else
379                 cst->state -= 6;
380 }
381
382 static inline void INIT process_bit1(struct writer *wr, struct rc *rc,
383                                             struct cstate *cst, uint16_t *p,
384                                             int pos_state, uint16_t *prob) {
385   int offset;
386         uint16_t *prob_len;
387         int num_bits;
388         int len;
389
390         rc_update_bit_1(rc, prob);
391         prob = p + LZMA_IS_REP + cst->state;
392         if (rc_is_bit_0(rc, prob)) {
393                 rc_update_bit_0(rc, prob);
394                 cst->rep3 = cst->rep2;
395                 cst->rep2 = cst->rep1;
396                 cst->rep1 = cst->rep0;
397                 cst->state = cst->state < LZMA_NUM_LIT_STATES ? 0 : 3;
398                 prob = p + LZMA_LEN_CODER;
399         } else {
400                 rc_update_bit_1(rc, prob);
401                 prob = p + LZMA_IS_REP_G0 + cst->state;
402                 if (rc_is_bit_0(rc, prob)) {
403                         rc_update_bit_0(rc, prob);
404                         prob = (p + LZMA_IS_REP_0_LONG
405                                 + (cst->state <<
406                                    LZMA_NUM_POS_BITS_MAX) +
407                                 pos_state);
408                         if (rc_is_bit_0(rc, prob)) {
409                                 rc_update_bit_0(rc, prob);
410
411                                 cst->state = cst->state < LZMA_NUM_LIT_STATES ?
412                                         9 : 11;
413                                 copy_byte(wr, cst->rep0);
414                                 return;
415                         } else {
416                                 rc_update_bit_1(rc, prob);
417                         }
418                 } else {
419                         uint32_t distance;
420
421                         rc_update_bit_1(rc, prob);
422                         prob = p + LZMA_IS_REP_G1 + cst->state;
423                         if (rc_is_bit_0(rc, prob)) {
424                                 rc_update_bit_0(rc, prob);
425                                 distance = cst->rep1;
426                         } else {
427                                 rc_update_bit_1(rc, prob);
428                                 prob = p + LZMA_IS_REP_G2 + cst->state;
429                                 if (rc_is_bit_0(rc, prob)) {
430                                         rc_update_bit_0(rc, prob);
431                                         distance = cst->rep2;
432                                 } else {
433                                         rc_update_bit_1(rc, prob);
434                                         distance = cst->rep3;
435                                         cst->rep3 = cst->rep2;
436                                 }
437                                 cst->rep2 = cst->rep1;
438                         }
439                         cst->rep1 = cst->rep0;
440                         cst->rep0 = distance;
441                 }
442                 cst->state = cst->state < LZMA_NUM_LIT_STATES ? 8 : 11;
443                 prob = p + LZMA_REP_LEN_CODER;
444         }
445
446         prob_len = prob + LZMA_LEN_CHOICE;
447         if (rc_is_bit_0(rc, prob_len)) {
448                 rc_update_bit_0(rc, prob_len);
449                 prob_len = (prob + LZMA_LEN_LOW
450                             + (pos_state <<
451                                LZMA_LEN_NUM_LOW_BITS));
452                 offset = 0;
453                 num_bits = LZMA_LEN_NUM_LOW_BITS;
454         } else {
455                 rc_update_bit_1(rc, prob_len);
456                 prob_len = prob + LZMA_LEN_CHOICE_2;
457                 if (rc_is_bit_0(rc, prob_len)) {
458                         rc_update_bit_0(rc, prob_len);
459                         prob_len = (prob + LZMA_LEN_MID
460                                     + (pos_state <<
461                                        LZMA_LEN_NUM_MID_BITS));
462                         offset = 1 << LZMA_LEN_NUM_LOW_BITS;
463                         num_bits = LZMA_LEN_NUM_MID_BITS;
464                 } else {
465                         rc_update_bit_1(rc, prob_len);
466                         prob_len = prob + LZMA_LEN_HIGH;
467                         offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
468                                   + (1 << LZMA_LEN_NUM_MID_BITS));
469                         num_bits = LZMA_LEN_NUM_HIGH_BITS;
470                 }
471         }
472
473         rc_bit_tree_decode(rc, prob_len, num_bits, &len);
474         len += offset;
475
476         if (cst->state < 4) {
477                 int pos_slot;
478
479                 cst->state += LZMA_NUM_LIT_STATES;
480                 prob =
481                         p + LZMA_POS_SLOT +
482                         ((len <
483                           LZMA_NUM_LEN_TO_POS_STATES ? len :
484                           LZMA_NUM_LEN_TO_POS_STATES - 1)
485                          << LZMA_NUM_POS_SLOT_BITS);
486                 rc_bit_tree_decode(rc, prob,
487                                    LZMA_NUM_POS_SLOT_BITS,
488                                    &pos_slot);
489                 if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
490                         int i, mi;
491                         num_bits = (pos_slot >> 1) - 1;
492                         cst->rep0 = 2 | (pos_slot & 1);
493                         if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
494                                 cst->rep0 <<= num_bits;
495                                 prob = p + LZMA_SPEC_POS +
496                                         cst->rep0 - pos_slot - 1;
497                         } else {
498                                 num_bits -= LZMA_NUM_ALIGN_BITS;
499                                 while (num_bits--)
500                                         cst->rep0 = (cst->rep0 << 1) |
501                                                 rc_direct_bit(rc);
502                                 prob = p + LZMA_ALIGN;
503                                 cst->rep0 <<= LZMA_NUM_ALIGN_BITS;
504                                 num_bits = LZMA_NUM_ALIGN_BITS;
505                         }
506                         i = 1;
507                         mi = 1;
508                         while (num_bits--) {
509                                 if (rc_get_bit(rc, prob + mi, &mi))
510                                         cst->rep0 |= i;
511                                 i <<= 1;
512                         }
513                 } else
514                         cst->rep0 = pos_slot;
515                 if (++(cst->rep0) == 0)
516                         return;
517         }
518
519         len += LZMA_MATCH_MIN_LEN;
520
521         copy_bytes(wr, cst->rep0, len);
522 }
523
524
525
526 STATIC inline int INIT unlzma(unsigned char *buf, int in_len,
527                               int(*fill)(void*, unsigned int),
528                               int(*flush)(void*, unsigned int),
529                               unsigned char *output,
530                               int *posp,
531                               void(*error_fn)(char *x)
532         )
533 {
534         struct lzma_header header;
535         int lc, pb, lp;
536         uint32_t pos_state_mask;
537         uint32_t literal_pos_mask;
538         uint16_t *p;
539         int num_probs;
540         struct rc rc;
541         int i, mi;
542         struct writer wr;
543         struct cstate cst;
544         unsigned char *inbuf;
545         int ret = -1;
546
547         set_error_fn(error_fn);
548
549         if (buf)
550                 inbuf = buf;
551         else
552                 inbuf = malloc(LZMA_IOBUF_SIZE);
553         if (!inbuf) {
554                 error("Could not allocate input bufer");
555                 goto exit_0;
556         }
557
558         cst.state = 0;
559         cst.rep0 = cst.rep1 = cst.rep2 = cst.rep3 = 1;
560
561         wr.header = &header;
562         wr.flush = flush;
563         wr.global_pos = 0;
564         wr.previous_byte = 0;
565         wr.buffer_pos = 0;
566
567         rc_init(&rc, fill, inbuf, in_len);
568
569         for (i = 0; i < sizeof(header); i++) {
570                 if (rc.ptr >= rc.buffer_end)
571                         rc_read(&rc);
572                 ((unsigned char *)&header)[i] = *rc.ptr++;
573         }
574
575         if (header.pos >= (9 * 5 * 5))
576                 error("bad header");
577
578         mi = 0;
579         lc = header.pos;
580         while (lc >= 9) {
581                 mi++;
582                 lc -= 9;
583         }
584         pb = 0;
585         lp = mi;
586         while (lp >= 5) {
587                 pb++;
588                 lp -= 5;
589         }
590         pos_state_mask = (1 << pb) - 1;
591         literal_pos_mask = (1 << lp) - 1;
592
593         ENDIAN_CONVERT(header.dict_size);
594         ENDIAN_CONVERT(header.dst_size);
595
596         if (header.dict_size == 0)
597                 header.dict_size = 1;
598
599         if (output)
600                 wr.buffer = output;
601         else {
602                 wr.bufsize = MIN(header.dst_size, header.dict_size);
603                 wr.buffer = large_malloc(wr.bufsize);
604         }
605         if (wr.buffer == NULL)
606                 goto exit_1;
607
608         num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
609         p = (uint16_t *) large_malloc(num_probs * sizeof(*p));
610         if (p == 0)
611                 goto exit_2;
612         num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
613         for (i = 0; i < num_probs; i++)
614                 p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
615
616         rc_init_code(&rc);
617
618         while (get_pos(&wr) < header.dst_size) {
619                 int pos_state = get_pos(&wr) & pos_state_mask;
620                 uint16_t *prob = p + LZMA_IS_MATCH +
621                         (cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state;
622                 if (rc_is_bit_0(&rc, prob))
623                         process_bit0(&wr, &rc, &cst, p, pos_state, prob,
624                                      lc, literal_pos_mask);
625                 else {
626                         process_bit1(&wr, &rc, &cst, p, pos_state, prob);
627                         if (cst.rep0 == 0)
628                                 break;
629                 }
630         }
631
632         if (posp)
633                 *posp = rc.ptr-rc.buffer;
634         if (wr.flush)
635                 wr.flush(wr.buffer, wr.buffer_pos);
636         ret = 0;
637         large_free(p);
638 exit_2:
639         if (!output)
640                 large_free(wr.buffer);
641 exit_1:
642         if (!buf)
643                 free(inbuf);
644 exit_0:
645         return ret;
646 }
647
648 #ifdef PREBOOT
649 STATIC int INIT decompress(unsigned char *buf, int in_len,
650                               int(*fill)(void*, unsigned int),
651                               int(*flush)(void*, unsigned int),
652                               unsigned char *output,
653                               int *posp,
654                               void(*error_fn)(char *x)
655         )
656 {
657         return unlzma(buf, in_len - 4, fill, flush, output, posp, error_fn);
658 }
659 #endif