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 #ifndef STATIC
  33 #include <linux/decompress/unlzma.h>
  34 #endif /* STATIC */
  35
  36 #include <linux/decompress/mm.h>
  37
  38 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
  39
  40 static long long INIT read_int(unsigned char *ptr, int size)
  41 {
  42         int i;
  43         long long ret = 0;
  44
  45         for (i = 0; i < size; i++)
  46                 ret = (ret << 8) | ptr[size-i-1];
  47         return ret;
  48 }
  49
  50 #define ENDIAN_CONVERT(x) \
  51   x = (typeof(x))read_int((unsigned char *)&x, sizeof(x))
  52
  53
  54 /* Small range coder implementation for lzma.
  55  *Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
  56  *
  57  *Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
  58  *Copyright (c) 1999-2005  Igor Pavlov
  59  */
  60
  61 #include <linux/compiler.h>
  62
  63 #define LZMA_IOBUF_SIZE 0x10000
  64
  65 struct rc {
  66         int (*fill)(void*, unsigned int);
  67         uint8_t *ptr;
  68         uint8_t *buffer;
  69         uint8_t *buffer_end;
  70         int buffer_size;
  71         uint32_t code;
  72         uint32_t range;
  73         uint32_t bound;
  74 };
  75
  76
  77 #define RC_TOP_BITS 24
  78 #define RC_MOVE_BITS 5
  79 #define RC_MODEL_TOTAL_BITS 11
  80
  81
  82 /* Called twice: once at startup and once in rc_normalize() */
  83 static void INIT rc_read(struct rc *rc)
  84 {
  85         rc->buffer_size = rc->fill((char *)rc->buffer, LZMA_IOBUF_SIZE);
  86         if (rc->buffer_size <= 0)
  87                 error("unexpected EOF");
  88         rc->ptr = rc->buffer;
  89         rc->buffer_end = rc->buffer + rc->buffer_size;
  90 }
  91
  92 /* Called once */
  93 static inline void INIT rc_init(struct rc *rc,
  94                                        int (*fill)(void*, unsigned int),
  95                                        char *buffer, int buffer_size)
  96 {
  97         rc->fill = fill;
  98         rc->buffer = (uint8_t *)buffer;
  99         rc->buffer_size = buffer_size;
 100         rc->buffer_end = rc->buffer + rc->buffer_size;
 101         rc->ptr = rc->buffer;
 102
 103         rc->code = 0;
 104         rc->range = 0xFFFFFFFF;
 105 }
 106
 107 static inline void INIT rc_init_code(struct rc *rc)
 108 {
 109         int i;
 110
 111         for (i = 0; i < 5; i++) {
 112                 if (rc->ptr >= rc->buffer_end)
 113                         rc_read(rc);
 114                 rc->code = (rc->code << 8) | *rc->ptr++;
 115         }
 116 }
 117
 118
 119 /* Called once. TODO: bb_maybe_free() */
 120 static inline void INIT rc_free(struct rc *rc)
 121 {
 122         free(rc->buffer);
 123 }
 124
 125 /* Called twice, but one callsite is in inline'd rc_is_bit_0_helper() */
 126 static void INIT rc_do_normalize(struct rc *rc)
 127 {
 128         if (rc->ptr >= rc->buffer_end)
 129                 rc_read(rc);
 130         rc->range <<= 8;
 131         rc->code = (rc->code << 8) | *rc->ptr++;
 132 }
 133 static inline void INIT rc_normalize(struct rc *rc)
 134 {
 135         if (rc->range < (1 << RC_TOP_BITS))
 136                 rc_do_normalize(rc);
 137 }
 138
 139 /* Called 9 times */
 140 /* Why rc_is_bit_0_helper exists?
 141  *Because we want to always expose (rc->code < rc->bound) to optimizer
 142  */
 143 static inline uint32_t INIT rc_is_bit_0_helper(struct rc *rc, uint16_t *p)
 144 {
 145         rc_normalize(rc);
 146         rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
 147         return rc->bound;
 148 }
 149 static inline int INIT rc_is_bit_0(struct rc *rc, uint16_t *p)
 150 {
 151         uint32_t t = rc_is_bit_0_helper(rc, p);
 152         return rc->code < t;
 153 }
 154
 155 /* Called ~10 times, but very small, thus inlined */
 156 static inline void INIT rc_update_bit_0(struct rc *rc, uint16_t *p)
 157 {
 158         rc->range = rc->bound;
 159         *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
 160 }
 161 static inline void rc_update_bit_1(struct rc *rc, uint16_t *p)
 162 {
 163         rc->range -= rc->bound;
 164         rc->code -= rc->bound;
 165         *p -= *p >> RC_MOVE_BITS;
 166 }
 167
 168 /* Called 4 times in unlzma loop */
 169 static int INIT rc_get_bit(struct rc *rc, uint16_t *p, int *symbol)
 170 {
 171         if (rc_is_bit_0(rc, p)) {
 172                 rc_update_bit_0(rc, p);
 173                 *symbol *= 2;
 174                 return 0;
 175         } else {
 176                 rc_update_bit_1(rc, p);
 177                 *symbol = *symbol * 2 + 1;
 178                 return 1;
 179         }
 180 }
 181
 182 /* Called once */
 183 static inline int INIT rc_direct_bit(struct rc *rc)
 184 {
 185         rc_normalize(rc);
 186         rc->range >>= 1;
 187         if (rc->code >= rc->range) {
 188                 rc->code -= rc->range;
 189                 return 1;
 190         }
 191         return 0;
 192 }
 193
 194 /* Called twice */
 195 static inline void INIT
 196 rc_bit_tree_decode(struct rc *rc, uint16_t *p, int num_levels, int *symbol)
 197 {
 198         int i = num_levels;
 199
 200         *symbol = 1;
 201         while (i--)
 202                 rc_get_bit(rc, p + *symbol, symbol);
 203         *symbol -= 1 << num_levels;
 204 }
 205
 206
 207 /*
 208  * Small lzma deflate implementation.
 209  * Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
 210  *
 211  * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
 212  * Copyright (C) 1999-2005  Igor Pavlov
 213  */
 214
 215
 216 struct lzma_header {
 217         uint8_t pos;
 218         uint32_t dict_size;
 219         uint64_t dst_size;
 220 } __attribute__ ((packed)) ;
 221
 222
 223 #define LZMA_BASE_SIZE 1846
 224 #define LZMA_LIT_SIZE 768
 225
 226 #define LZMA_NUM_POS_BITS_MAX 4
 227
 228 #define LZMA_LEN_NUM_LOW_BITS 3
 229 #define LZMA_LEN_NUM_MID_BITS 3
 230 #define LZMA_LEN_NUM_HIGH_BITS 8
 231
 232 #define LZMA_LEN_CHOICE 0
 233 #define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
 234 #define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
 235 #define LZMA_LEN_MID (LZMA_LEN_LOW \
 236                       + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
 237 #define LZMA_LEN_HIGH (LZMA_LEN_MID \
 238                        +(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
 239 #define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
 240
 241 #define LZMA_NUM_STATES 12
 242 #define LZMA_NUM_LIT_STATES 7
 243
 244 #define LZMA_START_POS_MODEL_INDEX 4
 245 #define LZMA_END_POS_MODEL_INDEX 14
 246 #define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
 247
 248 #define LZMA_NUM_POS_SLOT_BITS 6
 249 #define LZMA_NUM_LEN_TO_POS_STATES 4
 250
 251 #define LZMA_NUM_ALIGN_BITS 4
 252
 253 #define LZMA_MATCH_MIN_LEN 2
 254
 255 #define LZMA_IS_MATCH 0
 256 #define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
 257 #define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
 258 #define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
 259 #define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
 260 #define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
 261 #define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
 262                        + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
 263 #define LZMA_SPEC_POS (LZMA_POS_SLOT \
 264                        +(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
 265 #define LZMA_ALIGN (LZMA_SPEC_POS \
 266                     + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
 267 #define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
 268 #define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
 269 #define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
 270
 271
 272 struct writer {
 273         uint8_t *buffer;
 274         uint8_t previous_byte;
 275         size_t buffer_pos;
 276         int bufsize;
 277         size_t global_pos;
 278         int(*flush)(void*, unsigned int);
 279         struct lzma_header *header;
 280 };
 281
 282 struct cstate {
 283         int state;
 284         uint32_t rep0, rep1, rep2, rep3;
 285 };
 286
 287 static inline size_t INIT get_pos(struct writer *wr)
 288 {
 289         return
 290                 wr->global_pos + wr->buffer_pos;
 291 }
 292
 293 static inline uint8_t INIT peek_old_byte(struct writer *wr,
 294                                                 uint32_t offs)
 295 {
 296         if (!wr->flush) {
 297                 int32_t pos;
 298                 while (offs > wr->header->dict_size)
 299                         offs -= wr->header->dict_size;
 300                 pos = wr->buffer_pos - offs;
 301                 return wr->buffer[pos];
 302         } else {
 303                 uint32_t pos = wr->buffer_pos - offs;
 304                 while (pos >= wr->header->dict_size)
 305                         pos += wr->header->dict_size;
 306                 return wr->buffer[pos];
 307         }
 308
 309 }
 310
 311 static inline void INIT write_byte(struct writer *wr, uint8_t byte)
 312 {
 313         wr->buffer[wr->buffer_pos++] = wr->previous_byte = byte;
 314         if (wr->flush && wr->buffer_pos == wr->header->dict_size) {
 315                 wr->buffer_pos = 0;
 316                 wr->global_pos += wr->header->dict_size;
 317                 wr->flush((char *)wr->buffer, wr->header->dict_size);
 318         }
 319 }
 320
 321
 322 static inline void INIT copy_byte(struct writer *wr, uint32_t offs)
 323 {
 324         write_byte(wr, peek_old_byte(wr, offs));
 325 }
 326
 327 static inline void INIT copy_bytes(struct writer *wr,
 328                                          uint32_t rep0, int len)
 329 {
 330         do {
 331                 copy_byte(wr, rep0);
 332                 len--;
 333         } while (len != 0 && wr->buffer_pos < wr->header->dst_size);
 334 }
 335
 336 static inline void INIT process_bit0(struct writer *wr, struct rc *rc,
 337                                      struct cstate *cst, uint16_t *p,
 338                                      int pos_state, uint16_t *prob,
 339                                      int lc, uint32_t literal_pos_mask) {
 340         int mi = 1;
 341         rc_update_bit_0(rc, prob);
 342         prob = (p + LZMA_LITERAL +
 343                 (LZMA_LIT_SIZE
 344                  * (((get_pos(wr) & literal_pos_mask) << lc)
 345                     + (wr->previous_byte >> (8 - lc))))
 346                 );
 347
 348         if (cst->state >= LZMA_NUM_LIT_STATES) {
 349                 int match_byte = peek_old_byte(wr, cst->rep0);
 350                 do {
 351                         int bit;
 352                         uint16_t *prob_lit;
 353
 354                         match_byte <<= 1;
 355                         bit = match_byte & 0x100;
 356                         prob_lit = prob + 0x100 + bit + mi;
 357                         if (rc_get_bit(rc, prob_lit, &mi)) {
 358                                 if (!bit)
 359                                         break;
 360                         } else {
 361                                 if (bit)
 362                                         break;
 363                         }
 364                 } while (mi < 0x100);
 365         }
 366         while (mi < 0x100) {
 367                 uint16_t *prob_lit = prob + mi;
 368                 rc_get_bit(rc, prob_lit, &mi);
 369         }
 370         write_byte(wr, mi);
 371         if (cst->state < 4)
 372                 cst->state = 0;
 373         else if (cst->state < 10)
 374                 cst->state -= 3;
 375         else
 376                 cst->state -= 6;
 377 }
 378
 379 static inline void INIT process_bit1(struct writer *wr, struct rc *rc,
 380                                             struct cstate *cst, uint16_t *p,
 381                                             int pos_state, uint16_t *prob) {
 382   int offset;
 383         uint16_t *prob_len;
 384         int num_bits;
 385         int len;
 386
 387         rc_update_bit_1(rc, prob);
 388         prob = p + LZMA_IS_REP + cst->state;
 389         if (rc_is_bit_0(rc, prob)) {
 390                 rc_update_bit_0(rc, prob);
 391                 cst->rep3 = cst->rep2;
 392                 cst->rep2 = cst->rep1;
 393                 cst->rep1 = cst->rep0;
 394                 cst->state = cst->state < LZMA_NUM_LIT_STATES ? 0 : 3;
 395                 prob = p + LZMA_LEN_CODER;
 396         } else {
 397                 rc_update_bit_1(rc, prob);
 398                 prob = p + LZMA_IS_REP_G0 + cst->state;
 399                 if (rc_is_bit_0(rc, prob)) {
 400                         rc_update_bit_0(rc, prob);
 401                         prob = (p + LZMA_IS_REP_0_LONG
 402                                 + (cst->state <<
 403                                    LZMA_NUM_POS_BITS_MAX) +
 404                                 pos_state);
 405                         if (rc_is_bit_0(rc, prob)) {
 406                                 rc_update_bit_0(rc, prob);
 407
 408                                 cst->state = cst->state < LZMA_NUM_LIT_STATES ?
 409                                         9 : 11;
 410                                 copy_byte(wr, cst->rep0);
 411                                 return;
 412                         } else {
 413                                 rc_update_bit_1(rc, prob);
 414                         }
 415                 } else {
 416                         uint32_t distance;
 417
 418                         rc_update_bit_1(rc, prob);
 419                         prob = p + LZMA_IS_REP_G1 + cst->state;
 420                         if (rc_is_bit_0(rc, prob)) {
 421                                 rc_update_bit_0(rc, prob);
 422                                 distance = cst->rep1;
 423                         } else {
 424                                 rc_update_bit_1(rc, prob);
 425                                 prob = p + LZMA_IS_REP_G2 + cst->state;
 426                                 if (rc_is_bit_0(rc, prob)) {
 427                                         rc_update_bit_0(rc, prob);
 428                                         distance = cst->rep2;
 429                                 } else {
 430                                         rc_update_bit_1(rc, prob);
 431                                         distance = cst->rep3;
 432                                         cst->rep3 = cst->rep2;
 433                                 }
 434                                 cst->rep2 = cst->rep1;
 435                         }
 436                         cst->rep1 = cst->rep0;
 437                         cst->rep0 = distance;
 438                 }
 439                 cst->state = cst->state < LZMA_NUM_LIT_STATES ? 8 : 11;
 440                 prob = p + LZMA_REP_LEN_CODER;
 441         }
 442
 443         prob_len = prob + LZMA_LEN_CHOICE;
 444         if (rc_is_bit_0(rc, prob_len)) {
 445                 rc_update_bit_0(rc, prob_len);
 446                 prob_len = (prob + LZMA_LEN_LOW
 447                             + (pos_state <<
 448                                LZMA_LEN_NUM_LOW_BITS));
 449                 offset = 0;
 450                 num_bits = LZMA_LEN_NUM_LOW_BITS;
 451         } else {
 452                 rc_update_bit_1(rc, prob_len);
 453                 prob_len = prob + LZMA_LEN_CHOICE_2;
 454                 if (rc_is_bit_0(rc, prob_len)) {
 455                         rc_update_bit_0(rc, prob_len);
 456                         prob_len = (prob + LZMA_LEN_MID
 457                                     + (pos_state <<
 458                                        LZMA_LEN_NUM_MID_BITS));
 459                         offset = 1 << LZMA_LEN_NUM_LOW_BITS;
 460                         num_bits = LZMA_LEN_NUM_MID_BITS;
 461                 } else {
 462                         rc_update_bit_1(rc, prob_len);
 463                         prob_len = prob + LZMA_LEN_HIGH;
 464                         offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
 465                                   + (1 << LZMA_LEN_NUM_MID_BITS));
 466                         num_bits = LZMA_LEN_NUM_HIGH_BITS;
 467                 }
 468         }
 469
 470         rc_bit_tree_decode(rc, prob_len, num_bits, &len);
 471         len += offset;
 472
 473         if (cst->state < 4) {
 474                 int pos_slot;
 475
 476                 cst->state += LZMA_NUM_LIT_STATES;
 477                 prob =
 478                         p + LZMA_POS_SLOT +
 479                         ((len <
 480                           LZMA_NUM_LEN_TO_POS_STATES ? len :
 481                           LZMA_NUM_LEN_TO_POS_STATES - 1)
 482                          << LZMA_NUM_POS_SLOT_BITS);
 483                 rc_bit_tree_decode(rc, prob,
 484                                    LZMA_NUM_POS_SLOT_BITS,
 485                                    &pos_slot);
 486                 if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
 487                         int i, mi;
 488                         num_bits = (pos_slot >> 1) - 1;
 489                         cst->rep0 = 2 | (pos_slot & 1);
 490                         if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
 491                                 cst->rep0 <<= num_bits;
 492                                 prob = p + LZMA_SPEC_POS +
 493                                         cst->rep0 - pos_slot - 1;
 494                         } else {
 495                                 num_bits -= LZMA_NUM_ALIGN_BITS;
 496                                 while (num_bits--)
 497                                         cst->rep0 = (cst->rep0 << 1) |
 498                                                 rc_direct_bit(rc);
 499                                 prob = p + LZMA_ALIGN;
 500                                 cst->rep0 <<= LZMA_NUM_ALIGN_BITS;
 501                                 num_bits = LZMA_NUM_ALIGN_BITS;
 502                         }
 503                         i = 1;
 504                         mi = 1;
 505                         while (num_bits--) {
 506                                 if (rc_get_bit(rc, prob + mi, &mi))
 507                                         cst->rep0 |= i;
 508                                 i <<= 1;
 509                         }
 510                 } else
 511                         cst->rep0 = pos_slot;
 512                 if (++(cst->rep0) == 0)
 513                         return;
 514         }
 515
 516         len += LZMA_MATCH_MIN_LEN;
 517
 518         copy_bytes(wr, cst->rep0, len);
 519 }
 520
 521
 522
 523 STATIC inline int INIT unlzma(unsigned char *buf, int in_len,
 524                               int(*fill)(void*, unsigned int),
 525                               int(*flush)(void*, unsigned int),
 526                               unsigned char *output,
 527                               int *posp,
 528                               void(*error_fn)(char *x)
 529         )
 530 {
 531         struct lzma_header header;
 532         int lc, pb, lp;
 533         uint32_t pos_state_mask;
 534         uint32_t literal_pos_mask;
 535         uint16_t *p;
 536         int num_probs;
 537         struct rc rc;
 538         int i, mi;
 539         struct writer wr;
 540         struct cstate cst;
 541         unsigned char *inbuf;
 542         int ret = -1;
 543
 544         set_error_fn(error_fn);
 545         if (!flush)
 546                 in_len -= 4; /* Uncompressed size hack active in pre-boot
 547                                 environment */
 548         if (buf)
 549                 inbuf = buf;
 550         else
 551                 inbuf = malloc(LZMA_IOBUF_SIZE);
 552         if (!inbuf) {
 553                 error("Could not allocate input bufer");
 554                 goto exit_0;
 555         }
 556
 557         cst.state = 0;
 558         cst.rep0 = cst.rep1 = cst.rep2 = cst.rep3 = 1;
 559
 560         wr.header = &header;
 561         wr.flush = flush;
 562         wr.global_pos = 0;
 563         wr.previous_byte = 0;
 564         wr.buffer_pos = 0;
 565
 566         rc_init(&rc, fill, inbuf, in_len);
 567
 568         for (i = 0; i < sizeof(header); i++) {
 569                 if (rc.ptr >= rc.buffer_end)
 570                         rc_read(&rc);
 571                 ((unsigned char *)&header)[i] = *rc.ptr++;
 572         }
 573
 574         if (header.pos >= (9 * 5 * 5))
 575                 error("bad header");
 576
 577         mi = 0;
 578         lc = header.pos;
 579         while (lc >= 9) {
 580                 mi++;
 581                 lc -= 9;
 582         }
 583         pb = 0;
 584         lp = mi;
 585         while (lp >= 5) {
 586                 pb++;
 587                 lp -= 5;
 588         }
 589         pos_state_mask = (1 << pb) - 1;
 590         literal_pos_mask = (1 << lp) - 1;
 591
 592         ENDIAN_CONVERT(header.dict_size);
 593         ENDIAN_CONVERT(header.dst_size);
 594
 595         if (header.dict_size == 0)
 596                 header.dict_size = 1;
 597
 598         if (output)
 599                 wr.buffer = output;
 600         else {
 601                 wr.bufsize = MIN(header.dst_size, header.dict_size);
 602                 wr.buffer = large_malloc(wr.bufsize);
 603         }
 604         if (wr.buffer == NULL)
 605                 goto exit_1;
 606
 607         num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
 608         p = (uint16_t *) large_malloc(num_probs * sizeof(*p));
 609         if (p == 0)
 610                 goto exit_2;
 611         num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
 612         for (i = 0; i < num_probs; i++)
 613                 p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
 614
 615         rc_init_code(&rc);
 616
 617         while (get_pos(&wr) < header.dst_size) {
 618                 int pos_state = get_pos(&wr) & pos_state_mask;
 619                 uint16_t *prob = p + LZMA_IS_MATCH +
 620                         (cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state;
 621                 if (rc_is_bit_0(&rc, prob))
 622                         process_bit0(&wr, &rc, &cst, p, pos_state, prob,
 623                                      lc, literal_pos_mask);
 624                 else {
 625                         process_bit1(&wr, &rc, &cst, p, pos_state, prob);
 626                         if (cst.rep0 == 0)
 627                                 break;
 628                 }
 629         }
 630
 631         if (posp)
 632                 *posp = rc.ptr-rc.buffer;
 633         if (wr.flush)
 634                 wr.flush(wr.buffer, wr.buffer_pos);
 635         ret = 0;
 636         large_free(p);
 637 exit_2:
 638         if (!output)
 639                 large_free(wr.buffer);
 640 exit_1:
 641         if (!buf)
 642                 free(inbuf);
 643 exit_0:
 644         return ret;
 645 }
 646
 647 #define decompress unlzma