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Linux/lib/decompress_unlzma.c

Version: ~ [ linux-6.11-rc3 ] ~ [ linux-6.10.4 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.45 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.104 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.164 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.223 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.281 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.319 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
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  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 

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