archival/libunarchive/decompress_unlzma.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Small lzma deflate implementation.
   4  * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
   5  *
   6  * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
   7  * Copyright (C) 1999-2005  Igor Pavlov
   8  *
   9  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  10  */
  11
  12 #include "libbb.h"
  13 #include "unarchive.h"
  14
  15 #ifdef CONFIG_FEATURE_LZMA_FAST
  16 #  define speed_inline ATTRIBUTE_ALWAYS_INLINE
  17 #else
  18 #  define speed_inline
  19 #endif
  20
  21
  22 typedef struct {
  23         int fd;
  24         uint8_t *ptr;
  25         uint8_t *buffer;
  26         uint8_t *buffer_end;
  27         int buffer_size;
  28         uint32_t code;
  29         uint32_t range;
  30         uint32_t bound;
  31 } rc_t;
  32
  33
  34 #define RC_TOP_BITS 24
  35 #define RC_MOVE_BITS 5
  36 #define RC_MODEL_TOTAL_BITS 11
  37
  38
  39 /* Called twice: once at startup and once in rc_normalize() */
  40 static void rc_read(rc_t * rc)
  41 {
  42         rc->buffer_size = read(rc->fd, rc->buffer, rc->buffer_size);
  43         if (rc->buffer_size <= 0)
  44                 bb_error_msg_and_die("unexpected EOF");
  45         rc->ptr = rc->buffer;
  46         rc->buffer_end = rc->buffer + rc->buffer_size;
  47 }
  48
  49 /* Called once */
  50 static void rc_init(rc_t * rc, int fd, int buffer_size)
  51 {
  52         int i;
  53
  54         rc->fd = fd;
  55         rc->buffer = xmalloc(buffer_size);
  56         rc->buffer_size = buffer_size;
  57         rc->buffer_end = rc->buffer + rc->buffer_size;
  58         rc->ptr = rc->buffer_end;
  59
  60         rc->code = 0;
  61         rc->range = 0xFFFFFFFF;
  62         for (i = 0; i < 5; i++) {
  63                 if (rc->ptr >= rc->buffer_end)
  64                         rc_read(rc);
  65                 rc->code = (rc->code << 8) | *rc->ptr++;
  66         }
  67 }
  68
  69 /* Called once. TODO: bb_maybe_free() */
  70 static ATTRIBUTE_ALWAYS_INLINE void rc_free(rc_t * rc)
  71 {
  72         if (ENABLE_FEATURE_CLEAN_UP)
  73                 free(rc->buffer);
  74 }
  75
  76 /* Called twice, but one callsite is in speed_inline'd rc_is_bit_0_helper() */
  77 static void rc_do_normalize(rc_t * rc)
  78 {
  79         if (rc->ptr >= rc->buffer_end)
  80                 rc_read(rc);
  81         rc->range <<= 8;
  82         rc->code = (rc->code << 8) | *rc->ptr++;
  83 }
  84 static ATTRIBUTE_ALWAYS_INLINE void rc_normalize(rc_t * rc)
  85 {
  86         if (rc->range < (1 << RC_TOP_BITS)) {
  87                 rc_do_normalize(rc);
  88         }
  89 }
  90
  91 /* Called 9 times */
  92 /* Why rc_is_bit_0_helper exists?
  93  * Because we want to always expose (rc->code < rc->bound) to optimizer
  94  */
  95 static speed_inline uint32_t rc_is_bit_0_helper(rc_t * rc, uint16_t * p)
  96 {
  97         rc_normalize(rc);
  98         rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
  99         return rc->bound;
 100 }
 101 static ATTRIBUTE_ALWAYS_INLINE int rc_is_bit_0(rc_t * rc, uint16_t * p)
 102 {
 103         uint32_t t = rc_is_bit_0_helper(rc, p);
 104         return rc->code < t;
 105 }
 106
 107 /* Called ~10 times, but very small, thus inlined */
 108 static speed_inline void rc_update_bit_0(rc_t * rc, uint16_t * p)
 109 {
 110         rc->range = rc->bound;
 111         *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
 112 }
 113 static speed_inline void rc_update_bit_1(rc_t * rc, uint16_t * p)
 114 {
 115         rc->range -= rc->bound;
 116         rc->code -= rc->bound;
 117         *p -= *p >> RC_MOVE_BITS;
 118 }
 119
 120 /* Called 4 times in unlzma loop */
 121 static int rc_get_bit(rc_t * rc, uint16_t * p, int *symbol)
 122 {
 123         if (rc_is_bit_0(rc, p)) {
 124                 rc_update_bit_0(rc, p);
 125                 *symbol *= 2;
 126                 return 0;
 127         } else {
 128                 rc_update_bit_1(rc, p);
 129                 *symbol = *symbol * 2 + 1;
 130                 return 1;
 131         }
 132 }
 133
 134 /* Called once */
 135 static ATTRIBUTE_ALWAYS_INLINE int rc_direct_bit(rc_t * rc)
 136 {
 137         rc_normalize(rc);
 138         rc->range >>= 1;
 139         if (rc->code >= rc->range) {
 140                 rc->code -= rc->range;
 141                 return 1;
 142         }
 143         return 0;
 144 }
 145
 146 /* Called twice */
 147 static speed_inline void
 148 rc_bit_tree_decode(rc_t * rc, uint16_t * p, int num_levels, int *symbol)
 149 {
 150         int i = num_levels;
 151
 152         *symbol = 1;
 153         while (i--)
 154                 rc_get_bit(rc, p + *symbol, symbol);
 155         *symbol -= 1 << num_levels;
 156 }
 157
 158
 159 typedef struct {
 160         uint8_t pos;
 161         uint32_t dict_size;
 162         uint64_t dst_size;
 163 } __attribute__ ((packed)) lzma_header_t;
 164
 165
 166 #define LZMA_BASE_SIZE 1846
 167 #define LZMA_LIT_SIZE 768
 168
 169 #define LZMA_NUM_POS_BITS_MAX 4
 170
 171 #define LZMA_LEN_NUM_LOW_BITS 3
 172 #define LZMA_LEN_NUM_MID_BITS 3
 173 #define LZMA_LEN_NUM_HIGH_BITS 8
 174
 175 #define LZMA_LEN_CHOICE 0
 176 #define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
 177 #define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
 178 #define LZMA_LEN_MID (LZMA_LEN_LOW \
 179                       + (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
 180 #define LZMA_LEN_HIGH (LZMA_LEN_MID \
 181                        +(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
 182 #define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
 183
 184 #define LZMA_NUM_STATES 12
 185 #define LZMA_NUM_LIT_STATES 7
 186
 187 #define LZMA_START_POS_MODEL_INDEX 4
 188 #define LZMA_END_POS_MODEL_INDEX 14
 189 #define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
 190
 191 #define LZMA_NUM_POS_SLOT_BITS 6
 192 #define LZMA_NUM_LEN_TO_POS_STATES 4
 193
 194 #define LZMA_NUM_ALIGN_BITS 4
 195
 196 #define LZMA_MATCH_MIN_LEN 2
 197
 198 #define LZMA_IS_MATCH 0
 199 #define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES <<LZMA_NUM_POS_BITS_MAX))
 200 #define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
 201 #define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
 202 #define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
 203 #define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
 204 #define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
 205                        + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
 206 #define LZMA_SPEC_POS (LZMA_POS_SLOT \
 207                        +(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
 208 #define LZMA_ALIGN (LZMA_SPEC_POS \
 209                     + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
 210 #define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
 211 #define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
 212 #define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
 213
 214
 215 int unlzma(int src_fd, int dst_fd)
 216 {
 217         lzma_header_t header;
 218         int lc, pb, lp;
 219         uint32_t pos_state_mask;
 220         uint32_t literal_pos_mask;
 221         uint32_t pos;
 222         uint16_t *p;
 223         uint16_t *prob;
 224         uint16_t *prob_lit;
 225         int num_bits;
 226         int num_probs;
 227         rc_t rc;
 228         int i, mi;
 229         uint8_t *buffer;
 230         uint8_t previous_byte = 0;
 231         size_t buffer_pos = 0, global_pos = 0;
 232         int len = 0;
 233         int state = 0;
 234         uint32_t rep0 = 1, rep1 = 1, rep2 = 1, rep3 = 1;
 235
 236         if (read(src_fd, &header, sizeof(header)) != sizeof(header))
 237                 bb_error_msg_and_die("can't read header");
 238
 239         if (header.pos >= (9 * 5 * 5))
 240                 bb_error_msg_and_die("bad header");
 241         mi = header.pos / 9;
 242         lc = header.pos % 9;
 243         pb = mi / 5;
 244         lp = mi % 5;
 245         pos_state_mask = (1 << pb) - 1;
 246         literal_pos_mask = (1 << lp) - 1;
 247
 248         header.dict_size = SWAP_LE32(header.dict_size);
 249         header.dst_size = SWAP_LE64(header.dst_size);
 250
 251         if (header.dict_size == 0)
 252                 header.dict_size = 1;
 253
 254         buffer = xmalloc(MIN(header.dst_size, header.dict_size));
 255
 256         num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
 257         p = xmalloc(num_probs * sizeof(*p));
 258         num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
 259         for (i = 0; i < num_probs; i++)
 260                 p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
 261
 262         rc_init(&rc, src_fd, 0x10000);
 263
 264         while (global_pos + buffer_pos < header.dst_size) {
 265                 int pos_state = (buffer_pos + global_pos) & pos_state_mask;
 266
 267                 prob =
 268                         p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
 269                 if (rc_is_bit_0(&rc, prob)) {
 270                         mi = 1;
 271                         rc_update_bit_0(&rc, prob);
 272                         prob = (p + LZMA_LITERAL + (LZMA_LIT_SIZE
 273                                         * ((((buffer_pos + global_pos) & literal_pos_mask) << lc)
 274                                         + (previous_byte >> (8 - lc)))));
 275
 276                         if (state >= LZMA_NUM_LIT_STATES) {
 277                                 int match_byte;
 278
 279                                 pos = buffer_pos - rep0;
 280                                 while (pos >= header.dict_size)
 281                                         pos += header.dict_size;
 282                                 match_byte = buffer[pos];
 283                                 do {
 284                                         int bit;
 285
 286                                         match_byte <<= 1;
 287                                         bit = match_byte & 0x100;
 288                                         prob_lit = prob + 0x100 + bit + mi;
 289                                         if (rc_get_bit(&rc, prob_lit, &mi)) {
 290                                                 if (!bit)
 291                                                         break;
 292                                         } else {
 293                                                 if (bit)
 294                                                         break;
 295                                         }
 296                                 } while (mi < 0x100);
 297                         }
 298                         while (mi < 0x100) {
 299                                 prob_lit = prob + mi;
 300                                 rc_get_bit(&rc, prob_lit, &mi);
 301                         }
 302                         previous_byte = (uint8_t) mi;
 303
 304                         buffer[buffer_pos++] = previous_byte;
 305                         if (buffer_pos == header.dict_size) {
 306                                 buffer_pos = 0;
 307                                 global_pos += header.dict_size;
 308                                 write(dst_fd, buffer, header.dict_size);
 309                         }
 310                         if (state < 4)
 311                                 state = 0;
 312                         else if (state < 10)
 313                                 state -= 3;
 314                         else
 315                                 state -= 6;
 316                 } else {
 317                         int offset;
 318                         uint16_t *prob_len;
 319
 320                         rc_update_bit_1(&rc, prob);
 321                         prob = p + LZMA_IS_REP + state;
 322                         if (rc_is_bit_0(&rc, prob)) {
 323                                 rc_update_bit_0(&rc, prob);
 324                                 rep3 = rep2;
 325                                 rep2 = rep1;
 326                                 rep1 = rep0;
 327                                 state = state < LZMA_NUM_LIT_STATES ? 0 : 3;
 328                                 prob = p + LZMA_LEN_CODER;
 329                         } else {
 330                                 rc_update_bit_1(&rc, prob);
 331                                 prob = p + LZMA_IS_REP_G0 + state;
 332                                 if (rc_is_bit_0(&rc, prob)) {
 333                                         rc_update_bit_0(&rc, prob);
 334                                         prob = (p + LZMA_IS_REP_0_LONG
 335                                                         + (state << LZMA_NUM_POS_BITS_MAX) + pos_state);
 336                                         if (rc_is_bit_0(&rc, prob)) {
 337                                                 rc_update_bit_0(&rc, prob);
 338
 339                                                 state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
 340                                                 pos = buffer_pos - rep0;
 341                                                 while (pos >= header.dict_size)
 342                                                         pos += header.dict_size;
 343                                                 previous_byte = buffer[pos];
 344                                                 buffer[buffer_pos++] = previous_byte;
 345                                                 if (buffer_pos == header.dict_size) {
 346                                                         buffer_pos = 0;
 347                                                         global_pos += header.dict_size;
 348                                                         write(dst_fd, buffer, header.dict_size);
 349                                                 }
 350                                                 continue;
 351                                         } else {
 352                                                 rc_update_bit_1(&rc, prob);
 353                                         }
 354                                 } else {
 355                                         uint32_t distance;
 356
 357                                         rc_update_bit_1(&rc, prob);
 358                                         prob = p + LZMA_IS_REP_G1 + state;
 359                                         if (rc_is_bit_0(&rc, prob)) {
 360                                                 rc_update_bit_0(&rc, prob);
 361                                                 distance = rep1;
 362                                         } else {
 363                                                 rc_update_bit_1(&rc, prob);
 364                                                 prob = p + LZMA_IS_REP_G2 + state;
 365                                                 if (rc_is_bit_0(&rc, prob)) {
 366                                                         rc_update_bit_0(&rc, prob);
 367                                                         distance = rep2;
 368                                                 } else {
 369                                                         rc_update_bit_1(&rc, prob);
 370                                                         distance = rep3;
 371                                                         rep3 = rep2;
 372                                                 }
 373                                                 rep2 = rep1;
 374                                         }
 375                                         rep1 = rep0;
 376                                         rep0 = distance;
 377                                 }
 378                                 state = state < LZMA_NUM_LIT_STATES ? 8 : 11;
 379                                 prob = p + LZMA_REP_LEN_CODER;
 380                         }
 381
 382                         prob_len = prob + LZMA_LEN_CHOICE;
 383                         if (rc_is_bit_0(&rc, prob_len)) {
 384                                 rc_update_bit_0(&rc, prob_len);
 385                                 prob_len = (prob + LZMA_LEN_LOW
 386                                                         + (pos_state << LZMA_LEN_NUM_LOW_BITS));
 387                                 offset = 0;
 388                                 num_bits = LZMA_LEN_NUM_LOW_BITS;
 389                         } else {
 390                                 rc_update_bit_1(&rc, prob_len);
 391                                 prob_len = prob + LZMA_LEN_CHOICE_2;
 392                                 if (rc_is_bit_0(&rc, prob_len)) {
 393                                         rc_update_bit_0(&rc, prob_len);
 394                                         prob_len = (prob + LZMA_LEN_MID
 395                                                                 + (pos_state << LZMA_LEN_NUM_MID_BITS));
 396                                         offset = 1 << LZMA_LEN_NUM_LOW_BITS;
 397                                         num_bits = LZMA_LEN_NUM_MID_BITS;
 398                                 } else {
 399                                         rc_update_bit_1(&rc, prob_len);
 400                                         prob_len = prob + LZMA_LEN_HIGH;
 401                                         offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
 402                                                           + (1 << LZMA_LEN_NUM_MID_BITS));
 403                                         num_bits = LZMA_LEN_NUM_HIGH_BITS;
 404                                 }
 405                         }
 406                         rc_bit_tree_decode(&rc, prob_len, num_bits, &len);
 407                         len += offset;
 408
 409                         if (state < 4) {
 410                                 int pos_slot;
 411
 412                                 state += LZMA_NUM_LIT_STATES;
 413                                 prob =
 414                                         p + LZMA_POS_SLOT +
 415                                         ((len <
 416                                           LZMA_NUM_LEN_TO_POS_STATES ? len :
 417                                           LZMA_NUM_LEN_TO_POS_STATES - 1)
 418                                          << LZMA_NUM_POS_SLOT_BITS);
 419                                 rc_bit_tree_decode(&rc, prob, LZMA_NUM_POS_SLOT_BITS,
 420                                                                    &pos_slot);
 421                                 if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
 422                                         num_bits = (pos_slot >> 1) - 1;
 423                                         rep0 = 2 | (pos_slot & 1);
 424                                         if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
 425                                                 rep0 <<= num_bits;
 426                                                 prob = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
 427                                         } else {
 428                                                 num_bits -= LZMA_NUM_ALIGN_BITS;
 429                                                 while (num_bits--)
 430                                                         rep0 = (rep0 << 1) | rc_direct_bit(&rc);
 431                                                 prob = p + LZMA_ALIGN;
 432                                                 rep0 <<= LZMA_NUM_ALIGN_BITS;
 433                                                 num_bits = LZMA_NUM_ALIGN_BITS;
 434                                         }
 435                                         i = 1;
 436                                         mi = 1;
 437                                         while (num_bits--) {
 438                                                 if (rc_get_bit(&rc, prob + mi, &mi))
 439                                                         rep0 |= i;
 440                                                 i <<= 1;
 441                                         }
 442                                 } else
 443                                         rep0 = pos_slot;
 444                                 if (++rep0 == 0)
 445                                         break;
 446                         }
 447
 448                         len += LZMA_MATCH_MIN_LEN;
 449
 450                         do {
 451                                 pos = buffer_pos - rep0;
 452                                 while (pos >= header.dict_size)
 453                                         pos += header.dict_size;
 454                                 previous_byte = buffer[pos];
 455                                 buffer[buffer_pos++] = previous_byte;
 456                                 if (buffer_pos == header.dict_size) {
 457                                         buffer_pos = 0;
 458                                         global_pos += header.dict_size;
 459                                         write(dst_fd, buffer, header.dict_size);
 460                                 }
 461                                 len--;
 462                         } while (len != 0 && buffer_pos < header.dst_size);
 463                 }
 464         }
 465
 466         write(dst_fd, buffer, buffer_pos);
 467         rc_free(&rc);
 468         return 0;
 469 }
 470