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 < [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
  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 < [email protected] >
  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 < [email protected] >
 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