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decompress_unlzma.c
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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 < [email protected] >
6  *
7  *Based on small lzma deflate implementation/Small range coder
8  *implementation for lzma.
9  *Copyright (C) 2006 Aurelien Jacobs < [email protected] >
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
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 < [email protected] >
58  *
59  *Based on LzmaDecode.c from the LZMA SDK 4.22 (http://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  int (*fill)(void*, unsigned int);
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 int INIT nofill(void *buffer, unsigned int 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  int (*fill)(void*, unsigned int),
103  char *buffer, int 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 < [email protected] >
215  *
216  * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
217  * Copyright (C) 1999-2005 Igor Pavlov
218  */
219 
220 
221 struct lzma_header {
225 } __attribute__ ((packed)) ;
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 {
280  size_t buffer_pos;
281  int bufsize;
282  size_t global_pos;
283  int(*flush)(void*, unsigned int);
285 };
286 
287 struct cstate {
288  int state;
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 +
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 <<
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 <<
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 <<
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 <
494  rc_bit_tree_decode(rc, prob,
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, int in_len,
538  int(*fill)(void*, unsigned int),
539  int(*flush)(void*, unsigned int),
540  unsigned char *output,
541  int *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 == 0)
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, int in_len,
671  int(*fill)(void*, unsigned int),
672  int(*flush)(void*, unsigned int),
673  unsigned char *output,
674  int *posp,
675  void(*error)(char *x)
676  )
677 {
678  return unlzma(buf, in_len - 4, fill, flush, output, posp, error);
679 }
680 #endif