lib/decompress_unlzma.c

   1 /* Lzma decompressor for Linux kernel. Shamelessly snarfed
   2  *from busybox 1.1.1
   3  *
   4  *Linux kernel adaptation
   5  *Copyright (C) 2006  Alain < alain@knaff.lu >
   6  *
   7  *Based on small lzma deflate implementation/Small range coder
   8  *implementation for lzma.
   9  *Copyright (C) 2006  Aurelien Jacobs < aurel@gnuage.org >
  10  *
  11  *Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
  12  *Copyright (C) 1999-2005  Igor Pavlov
  13  *
  14  *Copyrights of the parts, see headers below.
  15  *
  16  *
  17  *This program is free software; you can redistribute it and/or
  18  *modify it under the terms of the GNU Lesser General Public
  19  *License as published by the Free Software Foundation; either
  20  *version 2.1 of the License, or (at your option) any later version.
  21  *
  22  *This program is distributed in the hope that it will be useful,
  23  *but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  *MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25  *Lesser General Public License for more details.
  26  *
  27  *You should have received a copy of the GNU Lesser General Public
  28  *License along with this library; if not, write to the Free Software
  29  *Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  30  */
  31
  32 #ifdef STATIC
  33 #define PREBOOT
  34 #else
  35 #include <linux/decompress/unlzma.h>
  36 #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 < aurel@gnuage.org >
  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);
  69         uint8_t *ptr;
  70         uint8_t *buffer;
  71         uint8_t *buffer_end;
  72         int buffer_size;
  73         uint32_t code;
  74         uint32_t range;
  75         uint32_t bound;
  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 < aurel@gnuage.org >
 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 {
 222         uint8_t pos;
 223         uint32_t dict_size;
 224         uint64_t dst_size;
 225 } __attribute__ ((packed)) ;
 226
 227
 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 {
 278         uint8_t *buffer;
 279         uint8_t previous_byte;
 280         size_t buffer_pos;
 281         int bufsize;
 282         size_t global_pos;
 283         int(*flush)(void*, unsigned int);
 284         struct lzma_header *header;
 285 };
 286
 287 struct cstate {
 288         int state;
 289         uint32_t rep0, rep1, rep2, rep3;
 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 void 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                 wr->flush((char *)wr->buffer, wr->header->dict_size);
 323         }
 324 }
 325
 326
 327 static inline void INIT copy_byte(struct writer *wr, uint32_t offs)
 328 {
 329         write_byte(wr, peek_old_byte(wr, offs));
 330 }
 331
 332 static inline void INIT copy_bytes(struct writer *wr,
 333                                          uint32_t rep0, int len)
 334 {
 335         do {
 336                 copy_byte(wr, rep0);
 337                 len--;
 338         } while (len != 0 && wr->buffer_pos < wr->header->dst_size);
 339 }
 340
 341 static inline void INIT process_bit0(struct writer *wr, struct rc *rc,
 342                                      struct cstate *cst, uint16_t *p,
 343                                      int pos_state, uint16_t *prob,
 344                                      int lc, uint32_t literal_pos_mask) {
 345         int mi = 1;
 346         rc_update_bit_0(rc, prob);
 347         prob = (p + LZMA_LITERAL +
 348                 (LZMA_LIT_SIZE
 349                  * (((get_pos(wr) & literal_pos_mask) << lc)
 350                     + (wr->previous_byte >> (8 - lc))))
 351                 );
 352
 353         if (cst->state >= LZMA_NUM_LIT_STATES) {
 354                 int match_byte = peek_old_byte(wr, cst->rep0);
 355                 do {
 356                         int bit;
 357                         uint16_t *prob_lit;
 358
 359                         match_byte <<= 1;
 360                         bit = match_byte & 0x100;
 361                         prob_lit = prob + 0x100 + bit + mi;
 362                         if (rc_get_bit(rc, prob_lit, &mi)) {
 363                                 if (!bit)
 364                                         break;
 365                         } else {
 366                                 if (bit)
 367                                         break;
 368                         }
 369                 } while (mi < 0x100);
 370         }
 371         while (mi < 0x100) {
 372                 uint16_t *prob_lit = prob + mi;
 373                 rc_get_bit(rc, prob_lit, &mi);
 374         }
 375         write_byte(wr, mi);
 376         if (cst->state < 4)
 377                 cst->state = 0;
 378         else if (cst->state < 10)
 379                 cst->state -= 3;
 380         else
 381                 cst->state -= 6;
 382 }
 383
 384 static inline void INIT process_bit1(struct writer *wr, struct rc *rc,
 385                                             struct cstate *cst, uint16_t *p,
 386                                             int pos_state, uint16_t *prob) {
 387   int offset;
 388         uint16_t *prob_len;
 389         int num_bits;
 390         int len;
 391
 392         rc_update_bit_1(rc, prob);
 393         prob = p + LZMA_IS_REP + cst->state;
 394         if (rc_is_bit_0(rc, prob)) {
 395                 rc_update_bit_0(rc, prob);
 396                 cst->rep3 = cst->rep2;
 397                 cst->rep2 = cst->rep1;
 398                 cst->rep1 = cst->rep0;
 399                 cst->state = cst->state < LZMA_NUM_LIT_STATES ? 0 : 3;
 400                 prob = p + LZMA_LEN_CODER;
 401         } else {
 402                 rc_update_bit_1(rc, prob);
 403                 prob = p + LZMA_IS_REP_G0 + cst->state;
 404                 if (rc_is_bit_0(rc, prob)) {
 405                         rc_update_bit_0(rc, prob);
 406                         prob = (p + LZMA_IS_REP_0_LONG
 407                                 + (cst->state <<
 408                                    LZMA_NUM_POS_BITS_MAX) +
 409                                 pos_state);
 410                         if (rc_is_bit_0(rc, prob)) {
 411                                 rc_update_bit_0(rc, prob);
 412
 413                                 cst->state = cst->state < LZMA_NUM_LIT_STATES ?
 414                                         9 : 11;
 415                                 copy_byte(wr, cst->rep0);
 416                                 return;
 417                         } else {
 418                                 rc_update_bit_1(rc, prob);
 419                         }
 420                 } else {
 421                         uint32_t distance;
 422
 423                         rc_update_bit_1(rc, prob);
 424                         prob = p + LZMA_IS_REP_G1 + cst->state;
 425                         if (rc_is_bit_0(rc, prob)) {
 426                                 rc_update_bit_0(rc, prob);
 427                                 distance = cst->rep1;
 428                         } else {
 429                                 rc_update_bit_1(rc, prob);
 430                                 prob = p + LZMA_IS_REP_G2 + cst->state;
 431                                 if (rc_is_bit_0(rc, prob)) {
 432                                         rc_update_bit_0(rc, prob);
 433                                         distance = cst->rep2;
 434                                 } else {
 435                                         rc_update_bit_1(rc, prob);
 436                                         distance = cst->rep3;
 437                                         cst->rep3 = cst->rep2;
 438                                 }
 439                                 cst->rep2 = cst->rep1;
 440                         }
 441                         cst->rep1 = cst->rep0;
 442                         cst->rep0 = distance;
 443                 }
 444                 cst->state = cst->state < LZMA_NUM_LIT_STATES ? 8 : 11;
 445                 prob = p + LZMA_REP_LEN_CODER;
 446         }
 447
 448         prob_len = prob + LZMA_LEN_CHOICE;
 449         if (rc_is_bit_0(rc, prob_len)) {
 450                 rc_update_bit_0(rc, prob_len);
 451                 prob_len = (prob + LZMA_LEN_LOW
 452                             + (pos_state <<
 453                                LZMA_LEN_NUM_LOW_BITS));
 454                 offset = 0;
 455                 num_bits = LZMA_LEN_NUM_LOW_BITS;
 456         } else {
 457                 rc_update_bit_1(rc, prob_len);
 458                 prob_len = prob + LZMA_LEN_CHOICE_2;
 459                 if (rc_is_bit_0(rc, prob_len)) {
 460                         rc_update_bit_0(rc, prob_len);
 461                         prob_len = (prob + LZMA_LEN_MID
 462                                     + (pos_state <<
 463                                        LZMA_LEN_NUM_MID_BITS));
 464                         offset = 1 << LZMA_LEN_NUM_LOW_BITS;
 465                         num_bits = LZMA_LEN_NUM_MID_BITS;
 466                 } else {
 467                         rc_update_bit_1(rc, prob_len);
 468                         prob_len = prob + LZMA_LEN_HIGH;
 469                         offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
 470                                   + (1 << LZMA_LEN_NUM_MID_BITS));
 471                         num_bits = LZMA_LEN_NUM_HIGH_BITS;
 472                 }
 473         }
 474
 475         rc_bit_tree_decode(rc, prob_len, num_bits, &len);
 476         len += offset;
 477
 478         if (cst->state < 4) {
 479                 int pos_slot;
 480
 481                 cst->state += LZMA_NUM_LIT_STATES;
 482                 prob =
 483                         p + LZMA_POS_SLOT +
 484                         ((len <
 485                           LZMA_NUM_LEN_TO_POS_STATES ? len :
 486                           LZMA_NUM_LEN_TO_POS_STATES - 1)
 487                          << LZMA_NUM_POS_SLOT_BITS);
 488                 rc_bit_tree_decode(rc, prob,
 489                                    LZMA_NUM_POS_SLOT_BITS,
 490                                    &pos_slot);
 491                 if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
 492                         int i, mi;
 493                         num_bits = (pos_slot >> 1) - 1;
 494                         cst->rep0 = 2 | (pos_slot & 1);
 495                         if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
 496                                 cst->rep0 <<= num_bits;
 497                                 prob = p + LZMA_SPEC_POS +
 498                                         cst->rep0 - pos_slot - 1;
 499                         } else {
 500                                 num_bits -= LZMA_NUM_ALIGN_BITS;
 501                                 while (num_bits--)
 502                                         cst->rep0 = (cst->rep0 << 1) |
 503                                                 rc_direct_bit(rc);
 504                                 prob = p + LZMA_ALIGN;
 505                                 cst->rep0 <<= LZMA_NUM_ALIGN_BITS;
 506                                 num_bits = LZMA_NUM_ALIGN_BITS;
 507                         }
 508                         i = 1;
 509                         mi = 1;
 510                         while (num_bits--) {
 511                                 if (rc_get_bit(rc, prob + mi, &mi))
 512                                         cst->rep0 |= i;
 513                                 i <<= 1;
 514                         }
 515                 } else
 516                         cst->rep0 = pos_slot;
 517                 if (++(cst->rep0) == 0)
 518                         return;
 519         }
 520
 521         len += LZMA_MATCH_MIN_LEN;
 522
 523         copy_bytes(wr, cst->rep0, len);
 524 }
 525
 526
 527
 528 STATIC inline int INIT unlzma(unsigned char *buf, int in_len,
 529                               int(*fill)(void*, unsigned int),
 530                               int(*flush)(void*, unsigned int),
 531                               unsigned char *output,
 532                               int *posp,
 533                               void(*error)(char *x)
 534         )
 535 {
 536         struct lzma_header header;
 537         int lc, pb, lp;
 538         uint32_t pos_state_mask;
 539         uint32_t literal_pos_mask;
 540         uint16_t *p;
 541         int num_probs;
 542         struct rc rc;
 543         int i, mi;
 544         struct writer wr;
 545         struct cstate cst;
 546         unsigned char *inbuf;
 547         int ret = -1;
 548
 549         rc.error = error;
 550
 551         if (buf)
 552                 inbuf = buf;
 553         else
 554                 inbuf = malloc(LZMA_IOBUF_SIZE);
 555         if (!inbuf) {
 556                 error("Could not allocate input bufer");
 557                 goto exit_0;
 558         }
 559
 560         cst.state = 0;
 561         cst.rep0 = cst.rep1 = cst.rep2 = cst.rep3 = 1;
 562
 563         wr.header = &header;
 564         wr.flush = flush;
 565         wr.global_pos = 0;
 566         wr.previous_byte = 0;
 567         wr.buffer_pos = 0;
 568
 569         rc_init(&rc, fill, inbuf, in_len);
 570
 571         for (i = 0; i < sizeof(header); i++) {
 572                 if (rc.ptr >= rc.buffer_end)
 573                         rc_read(&rc);
 574                 ((unsigned char *)&header)[i] = *rc.ptr++;
 575         }
 576
 577         if (header.pos >= (9 * 5 * 5)) {
 578                 error("bad header");
 579                 goto exit_1;
 580         }
 581
 582         mi = 0;
 583         lc = header.pos;
 584         while (lc >= 9) {
 585                 mi++;
 586                 lc -= 9;
 587         }
 588         pb = 0;
 589         lp = mi;
 590         while (lp >= 5) {
 591                 pb++;
 592                 lp -= 5;
 593         }
 594         pos_state_mask = (1 << pb) - 1;
 595         literal_pos_mask = (1 << lp) - 1;
 596
 597         ENDIAN_CONVERT(header.dict_size);
 598         ENDIAN_CONVERT(header.dst_size);
 599
 600         if (header.dict_size == 0)
 601                 header.dict_size = 1;
 602
 603         if (output)
 604                 wr.buffer = output;
 605         else {
 606                 wr.bufsize = MIN(header.dst_size, header.dict_size);
 607                 wr.buffer = large_malloc(wr.bufsize);
 608         }
 609         if (wr.buffer == NULL)
 610                 goto exit_1;
 611
 612         num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
 613         p = (uint16_t *) large_malloc(num_probs * sizeof(*p));
 614         if (p == 0)
 615                 goto exit_2;
 616         num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
 617         for (i = 0; i < num_probs; i++)
 618                 p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
 619
 620         rc_init_code(&rc);
 621
 622         while (get_pos(&wr) < header.dst_size) {
 623                 int pos_state = get_pos(&wr) & pos_state_mask;
 624                 uint16_t *prob = p + LZMA_IS_MATCH +
 625                         (cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state;
 626                 if (rc_is_bit_0(&rc, prob))
 627                         process_bit0(&wr, &rc, &cst, p, pos_state, prob,
 628                                      lc, literal_pos_mask);
 629                 else {
 630                         process_bit1(&wr, &rc, &cst, p, pos_state, prob);
 631                         if (cst.rep0 == 0)
 632                                 break;
 633                 }
 634         }
 635
 636         if (posp)
 637                 *posp = rc.ptr-rc.buffer;
 638         if (wr.flush)
 639                 wr.flush(wr.buffer, wr.buffer_pos);
 640         ret = 0;
 641         large_free(p);
 642 exit_2:
 643         if (!output)
 644                 large_free(wr.buffer);
 645 exit_1:
 646         if (!buf)
 647                 free(inbuf);
 648 exit_0:
 649         return ret;
 650 }
 651
 652 #ifdef PREBOOT
 653 STATIC int INIT decompress(unsigned char *buf, int in_len,
 654                               int(*fill)(void*, unsigned int),
 655                               int(*flush)(void*, unsigned int),
 656                               unsigned char *output,
 657                               int *posp,
 658                               void(*error)(char *x)
 659         )
 660 {
 661         return unlzma(buf, in_len - 4, fill, flush, output, posp, error);
 662 }
 663 #endif