[3320] | 1 | /*
|
---|
| 2 | * LZMA2 decoder
|
---|
| 3 | *
|
---|
| 4 | * Authors: Lasse Collin <lasse.collin@tukaani.org>
|
---|
| 5 | * Igor Pavlov <http://7-zip.org/>
|
---|
| 6 | *
|
---|
| 7 | * This file has been put into the public domain.
|
---|
| 8 | * You can do whatever you want with this file.
|
---|
| 9 | */
|
---|
| 10 |
|
---|
| 11 | #include "xz_private.h"
|
---|
| 12 | #include "xz_lzma2.h"
|
---|
| 13 |
|
---|
| 14 | /*
|
---|
| 15 | * Range decoder initialization eats the first five bytes of each LZMA chunk.
|
---|
| 16 | */
|
---|
| 17 | #define RC_INIT_BYTES 5
|
---|
| 18 |
|
---|
| 19 | /*
|
---|
| 20 | * Minimum number of usable input buffer to safely decode one LZMA symbol.
|
---|
| 21 | * The worst case is that we decode 22 bits using probabilities and 26
|
---|
| 22 | * direct bits. This may decode at maximum of 20 bytes of input. However,
|
---|
| 23 | * lzma_main() does an extra normalization before returning, thus we
|
---|
| 24 | * need to put 21 here.
|
---|
| 25 | */
|
---|
| 26 | #define LZMA_IN_REQUIRED 21
|
---|
| 27 |
|
---|
| 28 | /*
|
---|
| 29 | * Dictionary (history buffer)
|
---|
| 30 | *
|
---|
| 31 | * These are always true:
|
---|
| 32 | * start <= pos <= full <= end
|
---|
| 33 | * pos <= limit <= end
|
---|
| 34 | *
|
---|
| 35 | * In multi-call mode, also these are true:
|
---|
| 36 | * end == size
|
---|
| 37 | * size <= size_max
|
---|
| 38 | * allocated <= size
|
---|
| 39 | *
|
---|
| 40 | * Most of these variables are size_t to support single-call mode,
|
---|
| 41 | * in which the dictionary variables address the actual output
|
---|
| 42 | * buffer directly.
|
---|
| 43 | */
|
---|
| 44 | struct dictionary {
|
---|
| 45 | /* Beginning of the history buffer */
|
---|
| 46 | uint8_t *buf;
|
---|
| 47 |
|
---|
| 48 | /* Old position in buf (before decoding more data) */
|
---|
| 49 | size_t start;
|
---|
| 50 |
|
---|
| 51 | /* Position in buf */
|
---|
| 52 | size_t pos;
|
---|
| 53 |
|
---|
| 54 | /*
|
---|
| 55 | * How full dictionary is. This is used to detect corrupt input that
|
---|
| 56 | * would read beyond the beginning of the uncompressed stream.
|
---|
| 57 | */
|
---|
| 58 | size_t full;
|
---|
| 59 |
|
---|
| 60 | /* Write limit; we don't write to buf[limit] or later bytes. */
|
---|
| 61 | size_t limit;
|
---|
| 62 |
|
---|
| 63 | /*
|
---|
| 64 | * End of the dictionary buffer. In multi-call mode, this is
|
---|
| 65 | * the same as the dictionary size. In single-call mode, this
|
---|
| 66 | * indicates the size of the output buffer.
|
---|
| 67 | */
|
---|
| 68 | size_t end;
|
---|
| 69 |
|
---|
| 70 | /*
|
---|
| 71 | * Size of the dictionary as specified in Block Header. This is used
|
---|
| 72 | * together with "full" to detect corrupt input that would make us
|
---|
| 73 | * read beyond the beginning of the uncompressed stream.
|
---|
| 74 | */
|
---|
| 75 | uint32_t size;
|
---|
| 76 |
|
---|
| 77 | /*
|
---|
| 78 | * Maximum allowed dictionary size in multi-call mode.
|
---|
| 79 | * This is ignored in single-call mode.
|
---|
| 80 | */
|
---|
| 81 | uint32_t size_max;
|
---|
| 82 |
|
---|
| 83 | /*
|
---|
| 84 | * Amount of memory currently allocated for the dictionary.
|
---|
| 85 | * This is used only with XZ_DYNALLOC. (With XZ_PREALLOC,
|
---|
| 86 | * size_max is always the same as the allocated size.)
|
---|
| 87 | */
|
---|
| 88 | uint32_t allocated;
|
---|
| 89 |
|
---|
| 90 | /* Operation mode */
|
---|
| 91 | enum xz_mode mode;
|
---|
| 92 | };
|
---|
| 93 |
|
---|
| 94 | /* Range decoder */
|
---|
| 95 | struct rc_dec {
|
---|
| 96 | uint32_t range;
|
---|
| 97 | uint32_t code;
|
---|
| 98 |
|
---|
| 99 | /*
|
---|
| 100 | * Number of initializing bytes remaining to be read
|
---|
| 101 | * by rc_read_init().
|
---|
| 102 | */
|
---|
| 103 | uint32_t init_bytes_left;
|
---|
| 104 |
|
---|
| 105 | /*
|
---|
| 106 | * Buffer from which we read our input. It can be either
|
---|
| 107 | * temp.buf or the caller-provided input buffer.
|
---|
| 108 | */
|
---|
| 109 | const uint8_t *in;
|
---|
| 110 | size_t in_pos;
|
---|
| 111 | size_t in_limit;
|
---|
| 112 | };
|
---|
| 113 |
|
---|
| 114 | /* Probabilities for a length decoder. */
|
---|
| 115 | struct lzma_len_dec {
|
---|
| 116 | /* Probability of match length being at least 10 */
|
---|
| 117 | uint16_t choice;
|
---|
| 118 |
|
---|
| 119 | /* Probability of match length being at least 18 */
|
---|
| 120 | uint16_t choice2;
|
---|
| 121 |
|
---|
| 122 | /* Probabilities for match lengths 2-9 */
|
---|
| 123 | uint16_t low[POS_STATES_MAX][LEN_LOW_SYMBOLS];
|
---|
| 124 |
|
---|
| 125 | /* Probabilities for match lengths 10-17 */
|
---|
| 126 | uint16_t mid[POS_STATES_MAX][LEN_MID_SYMBOLS];
|
---|
| 127 |
|
---|
| 128 | /* Probabilities for match lengths 18-273 */
|
---|
| 129 | uint16_t high[LEN_HIGH_SYMBOLS];
|
---|
| 130 | };
|
---|
| 131 |
|
---|
| 132 | struct lzma_dec {
|
---|
| 133 | /* Distances of latest four matches */
|
---|
| 134 | uint32_t rep0;
|
---|
| 135 | uint32_t rep1;
|
---|
| 136 | uint32_t rep2;
|
---|
| 137 | uint32_t rep3;
|
---|
| 138 |
|
---|
| 139 | /* Types of the most recently seen LZMA symbols */
|
---|
| 140 | enum lzma_state state;
|
---|
| 141 |
|
---|
| 142 | /*
|
---|
| 143 | * Length of a match. This is updated so that dict_repeat can
|
---|
| 144 | * be called again to finish repeating the whole match.
|
---|
| 145 | */
|
---|
| 146 | uint32_t len;
|
---|
| 147 |
|
---|
| 148 | /*
|
---|
| 149 | * LZMA properties or related bit masks (number of literal
|
---|
| 150 | * context bits, a mask dervied from the number of literal
|
---|
| 151 | * position bits, and a mask dervied from the number
|
---|
| 152 | * position bits)
|
---|
| 153 | */
|
---|
| 154 | uint32_t lc;
|
---|
| 155 | uint32_t literal_pos_mask; /* (1 << lp) - 1 */
|
---|
| 156 | uint32_t pos_mask; /* (1 << pb) - 1 */
|
---|
| 157 |
|
---|
| 158 | /* If 1, it's a match. Otherwise it's a single 8-bit literal. */
|
---|
| 159 | uint16_t is_match[STATES][POS_STATES_MAX];
|
---|
| 160 |
|
---|
| 161 | /* If 1, it's a repeated match. The distance is one of rep0 .. rep3. */
|
---|
| 162 | uint16_t is_rep[STATES];
|
---|
| 163 |
|
---|
| 164 | /*
|
---|
| 165 | * If 0, distance of a repeated match is rep0.
|
---|
| 166 | * Otherwise check is_rep1.
|
---|
| 167 | */
|
---|
| 168 | uint16_t is_rep0[STATES];
|
---|
| 169 |
|
---|
| 170 | /*
|
---|
| 171 | * If 0, distance of a repeated match is rep1.
|
---|
| 172 | * Otherwise check is_rep2.
|
---|
| 173 | */
|
---|
| 174 | uint16_t is_rep1[STATES];
|
---|
| 175 |
|
---|
| 176 | /* If 0, distance of a repeated match is rep2. Otherwise it is rep3. */
|
---|
| 177 | uint16_t is_rep2[STATES];
|
---|
| 178 |
|
---|
| 179 | /*
|
---|
| 180 | * If 1, the repeated match has length of one byte. Otherwise
|
---|
| 181 | * the length is decoded from rep_len_decoder.
|
---|
| 182 | */
|
---|
| 183 | uint16_t is_rep0_long[STATES][POS_STATES_MAX];
|
---|
| 184 |
|
---|
| 185 | /*
|
---|
| 186 | * Probability tree for the highest two bits of the match
|
---|
| 187 | * distance. There is a separate probability tree for match
|
---|
| 188 | * lengths of 2 (i.e. MATCH_LEN_MIN), 3, 4, and [5, 273].
|
---|
| 189 | */
|
---|
| 190 | uint16_t dist_slot[DIST_STATES][DIST_SLOTS];
|
---|
| 191 |
|
---|
| 192 | /*
|
---|
| 193 | * Probility trees for additional bits for match distance
|
---|
| 194 | * when the distance is in the range [4, 127].
|
---|
| 195 | */
|
---|
| 196 | uint16_t dist_special[FULL_DISTANCES - DIST_MODEL_END];
|
---|
| 197 |
|
---|
| 198 | /*
|
---|
| 199 | * Probability tree for the lowest four bits of a match
|
---|
| 200 | * distance that is equal to or greater than 128.
|
---|
| 201 | */
|
---|
| 202 | uint16_t dist_align[ALIGN_SIZE];
|
---|
| 203 |
|
---|
| 204 | /* Length of a normal match */
|
---|
| 205 | struct lzma_len_dec match_len_dec;
|
---|
| 206 |
|
---|
| 207 | /* Length of a repeated match */
|
---|
| 208 | struct lzma_len_dec rep_len_dec;
|
---|
| 209 |
|
---|
| 210 | /* Probabilities of literals */
|
---|
| 211 | uint16_t literal[LITERAL_CODERS_MAX][LITERAL_CODER_SIZE];
|
---|
| 212 | };
|
---|
| 213 |
|
---|
| 214 | struct lzma2_dec {
|
---|
| 215 | /* Position in xz_dec_lzma2_run(). */
|
---|
| 216 | enum lzma2_seq {
|
---|
| 217 | SEQ_CONTROL,
|
---|
| 218 | SEQ_UNCOMPRESSED_1,
|
---|
| 219 | SEQ_UNCOMPRESSED_2,
|
---|
| 220 | SEQ_COMPRESSED_0,
|
---|
| 221 | SEQ_COMPRESSED_1,
|
---|
| 222 | SEQ_PROPERTIES,
|
---|
| 223 | SEQ_LZMA_PREPARE,
|
---|
| 224 | SEQ_LZMA_RUN,
|
---|
| 225 | SEQ_COPY
|
---|
| 226 | } sequence;
|
---|
| 227 |
|
---|
| 228 | /* Next position after decoding the compressed size of the chunk. */
|
---|
| 229 | enum lzma2_seq next_sequence;
|
---|
| 230 |
|
---|
| 231 | /* Uncompressed size of LZMA chunk (2 MiB at maximum) */
|
---|
| 232 | uint32_t uncompressed;
|
---|
| 233 |
|
---|
| 234 | /*
|
---|
| 235 | * Compressed size of LZMA chunk or compressed/uncompressed
|
---|
| 236 | * size of uncompressed chunk (64 KiB at maximum)
|
---|
| 237 | */
|
---|
| 238 | uint32_t compressed;
|
---|
| 239 |
|
---|
| 240 | /*
|
---|
| 241 | * True if dictionary reset is needed. This is false before
|
---|
| 242 | * the first chunk (LZMA or uncompressed).
|
---|
| 243 | */
|
---|
| 244 | bool need_dict_reset;
|
---|
| 245 |
|
---|
| 246 | /*
|
---|
| 247 | * True if new LZMA properties are needed. This is false
|
---|
| 248 | * before the first LZMA chunk.
|
---|
| 249 | */
|
---|
| 250 | bool need_props;
|
---|
| 251 | };
|
---|
| 252 |
|
---|
| 253 | struct xz_dec_lzma2 {
|
---|
| 254 | /*
|
---|
| 255 | * The order below is important on x86 to reduce code size and
|
---|
| 256 | * it shouldn't hurt on other platforms. Everything up to and
|
---|
| 257 | * including lzma.pos_mask are in the first 128 bytes on x86-32,
|
---|
| 258 | * which allows using smaller instructions to access those
|
---|
| 259 | * variables. On x86-64, fewer variables fit into the first 128
|
---|
| 260 | * bytes, but this is still the best order without sacrificing
|
---|
| 261 | * the readability by splitting the structures.
|
---|
| 262 | */
|
---|
| 263 | struct rc_dec rc;
|
---|
| 264 | struct dictionary dict;
|
---|
| 265 | struct lzma2_dec lzma2;
|
---|
| 266 | struct lzma_dec lzma;
|
---|
| 267 |
|
---|
| 268 | /*
|
---|
| 269 | * Temporary buffer which holds small number of input bytes between
|
---|
| 270 | * decoder calls. See lzma2_lzma() for details.
|
---|
| 271 | */
|
---|
| 272 | struct {
|
---|
| 273 | uint32_t size;
|
---|
| 274 | uint8_t buf[3 * LZMA_IN_REQUIRED];
|
---|
| 275 | } temp;
|
---|
| 276 | };
|
---|
| 277 |
|
---|
| 278 | /**************
|
---|
| 279 | * Dictionary *
|
---|
| 280 | **************/
|
---|
| 281 |
|
---|
| 282 | /*
|
---|
| 283 | * Reset the dictionary state. When in single-call mode, set up the beginning
|
---|
| 284 | * of the dictionary to point to the actual output buffer.
|
---|
| 285 | */
|
---|
| 286 | static void XZ_FUNC dict_reset(struct dictionary *dict, struct xz_buf *b)
|
---|
| 287 | {
|
---|
| 288 | if (DEC_IS_SINGLE(dict->mode)) {
|
---|
| 289 | dict->buf = b->out + b->out_pos;
|
---|
| 290 | dict->end = b->out_size - b->out_pos;
|
---|
| 291 | }
|
---|
| 292 |
|
---|
| 293 | dict->start = 0;
|
---|
| 294 | dict->pos = 0;
|
---|
| 295 | dict->limit = 0;
|
---|
| 296 | dict->full = 0;
|
---|
| 297 | }
|
---|
| 298 |
|
---|
| 299 | /* Set dictionary write limit */
|
---|
| 300 | static void XZ_FUNC dict_limit(struct dictionary *dict, size_t out_max)
|
---|
| 301 | {
|
---|
| 302 | if (dict->end - dict->pos <= out_max)
|
---|
| 303 | dict->limit = dict->end;
|
---|
| 304 | else
|
---|
| 305 | dict->limit = dict->pos + out_max;
|
---|
| 306 | }
|
---|
| 307 |
|
---|
| 308 | /* Return true if at least one byte can be written into the dictionary. */
|
---|
| 309 | static __always_inline bool XZ_FUNC dict_has_space(const struct dictionary *dict)
|
---|
| 310 | {
|
---|
| 311 | return dict->pos < dict->limit;
|
---|
| 312 | }
|
---|
| 313 |
|
---|
| 314 | /*
|
---|
| 315 | * Get a byte from the dictionary at the given distance. The distance is
|
---|
| 316 | * assumed to valid, or as a special case, zero when the dictionary is
|
---|
| 317 | * still empty. This special case is needed for single-call decoding to
|
---|
| 318 | * avoid writing a '\0' to the end of the destination buffer.
|
---|
| 319 | */
|
---|
| 320 | static __always_inline uint32_t XZ_FUNC dict_get(
|
---|
| 321 | const struct dictionary *dict, uint32_t dist)
|
---|
| 322 | {
|
---|
| 323 | size_t offset = dict->pos - dist - 1;
|
---|
| 324 |
|
---|
| 325 | if (dist >= dict->pos)
|
---|
| 326 | offset += dict->end;
|
---|
| 327 |
|
---|
| 328 | return dict->full > 0 ? dict->buf[offset] : 0;
|
---|
| 329 | }
|
---|
| 330 |
|
---|
| 331 | /*
|
---|
| 332 | * Put one byte into the dictionary. It is assumed that there is space for it.
|
---|
| 333 | */
|
---|
| 334 | static inline void XZ_FUNC dict_put(struct dictionary *dict, uint8_t byte)
|
---|
| 335 | {
|
---|
| 336 | dict->buf[dict->pos++] = byte;
|
---|
| 337 |
|
---|
| 338 | if (dict->full < dict->pos)
|
---|
| 339 | dict->full = dict->pos;
|
---|
| 340 | }
|
---|
| 341 |
|
---|
| 342 | /*
|
---|
| 343 | * Repeat given number of bytes from the given distance. If the distance is
|
---|
| 344 | * invalid, false is returned. On success, true is returned and *len is
|
---|
| 345 | * updated to indicate how many bytes were left to be repeated.
|
---|
| 346 | */
|
---|
| 347 | static bool XZ_FUNC dict_repeat(
|
---|
| 348 | struct dictionary *dict, uint32_t *len, uint32_t dist)
|
---|
| 349 | {
|
---|
| 350 | size_t back;
|
---|
| 351 | uint32_t left;
|
---|
| 352 |
|
---|
| 353 | if (dist >= dict->full || dist >= dict->size)
|
---|
| 354 | return false;
|
---|
| 355 |
|
---|
| 356 | left = min_t(size_t, dict->limit - dict->pos, *len);
|
---|
| 357 | *len -= left;
|
---|
| 358 |
|
---|
| 359 | back = dict->pos - dist - 1;
|
---|
| 360 | if (dist >= dict->pos)
|
---|
| 361 | back += dict->end;
|
---|
| 362 |
|
---|
| 363 | do {
|
---|
| 364 | dict->buf[dict->pos++] = dict->buf[back++];
|
---|
| 365 | if (back == dict->end)
|
---|
| 366 | back = 0;
|
---|
| 367 | } while (--left > 0);
|
---|
| 368 |
|
---|
| 369 | if (dict->full < dict->pos)
|
---|
| 370 | dict->full = dict->pos;
|
---|
| 371 |
|
---|
| 372 | return true;
|
---|
| 373 | }
|
---|
| 374 |
|
---|
| 375 | /* Copy uncompressed data as is from input to dictionary and output buffers. */
|
---|
| 376 | static void XZ_FUNC dict_uncompressed(
|
---|
| 377 | struct dictionary *dict, struct xz_buf *b, uint32_t *left)
|
---|
| 378 | {
|
---|
| 379 | size_t copy_size;
|
---|
| 380 |
|
---|
| 381 | while (*left > 0 && b->in_pos < b->in_size
|
---|
| 382 | && b->out_pos < b->out_size) {
|
---|
| 383 | copy_size = min(b->in_size - b->in_pos,
|
---|
| 384 | b->out_size - b->out_pos);
|
---|
| 385 | if (copy_size > dict->end - dict->pos)
|
---|
| 386 | copy_size = dict->end - dict->pos;
|
---|
| 387 | if (copy_size > *left)
|
---|
| 388 | copy_size = *left;
|
---|
| 389 |
|
---|
| 390 | *left -= copy_size;
|
---|
| 391 |
|
---|
| 392 | memcpy(dict->buf + dict->pos, b->in + b->in_pos, copy_size);
|
---|
| 393 | dict->pos += copy_size;
|
---|
| 394 |
|
---|
| 395 | if (dict->full < dict->pos)
|
---|
| 396 | dict->full = dict->pos;
|
---|
| 397 |
|
---|
| 398 | if (DEC_IS_MULTI(dict->mode)) {
|
---|
| 399 | if (dict->pos == dict->end)
|
---|
| 400 | dict->pos = 0;
|
---|
| 401 |
|
---|
| 402 | memcpy(b->out + b->out_pos, b->in + b->in_pos,
|
---|
| 403 | copy_size);
|
---|
| 404 | }
|
---|
| 405 |
|
---|
| 406 | dict->start = dict->pos;
|
---|
| 407 |
|
---|
| 408 | b->out_pos += copy_size;
|
---|
| 409 | b->in_pos += copy_size;
|
---|
| 410 |
|
---|
| 411 | }
|
---|
| 412 | }
|
---|
| 413 |
|
---|
| 414 | /*
|
---|
| 415 | * Flush pending data from dictionary to b->out. It is assumed that there is
|
---|
| 416 | * enough space in b->out. This is guaranteed because caller uses dict_limit()
|
---|
| 417 | * before decoding data into the dictionary.
|
---|
| 418 | */
|
---|
| 419 | static uint32_t XZ_FUNC dict_flush(struct dictionary *dict, struct xz_buf *b)
|
---|
| 420 | {
|
---|
| 421 | size_t copy_size = dict->pos - dict->start;
|
---|
| 422 |
|
---|
| 423 | if (DEC_IS_MULTI(dict->mode)) {
|
---|
| 424 | if (dict->pos == dict->end)
|
---|
| 425 | dict->pos = 0;
|
---|
| 426 |
|
---|
| 427 | memcpy(b->out + b->out_pos, dict->buf + dict->start,
|
---|
| 428 | copy_size);
|
---|
| 429 | }
|
---|
| 430 |
|
---|
| 431 | dict->start = dict->pos;
|
---|
| 432 | b->out_pos += copy_size;
|
---|
| 433 | return copy_size;
|
---|
| 434 | }
|
---|
| 435 |
|
---|
| 436 | /*****************
|
---|
| 437 | * Range decoder *
|
---|
| 438 | *****************/
|
---|
| 439 |
|
---|
| 440 | /* Reset the range decoder. */
|
---|
| 441 | static void XZ_FUNC rc_reset(struct rc_dec *rc)
|
---|
| 442 | {
|
---|
| 443 | rc->range = (uint32_t)-1;
|
---|
| 444 | rc->code = 0;
|
---|
| 445 | rc->init_bytes_left = RC_INIT_BYTES;
|
---|
| 446 | }
|
---|
| 447 |
|
---|
| 448 | /*
|
---|
| 449 | * Read the first five initial bytes into rc->code if they haven't been
|
---|
| 450 | * read already. (Yes, the first byte gets completely ignored.)
|
---|
| 451 | */
|
---|
| 452 | static bool XZ_FUNC rc_read_init(struct rc_dec *rc, struct xz_buf *b)
|
---|
| 453 | {
|
---|
| 454 | while (rc->init_bytes_left > 0) {
|
---|
| 455 | if (b->in_pos == b->in_size)
|
---|
| 456 | return false;
|
---|
| 457 |
|
---|
| 458 | rc->code = (rc->code << 8) + b->in[b->in_pos++];
|
---|
| 459 | --rc->init_bytes_left;
|
---|
| 460 | }
|
---|
| 461 |
|
---|
| 462 | return true;
|
---|
| 463 | }
|
---|
| 464 |
|
---|
| 465 | /* Return true if there may not be enough input for the next decoding loop. */
|
---|
| 466 | static inline bool XZ_FUNC rc_limit_exceeded(const struct rc_dec *rc)
|
---|
| 467 | {
|
---|
| 468 | return rc->in_pos > rc->in_limit;
|
---|
| 469 | }
|
---|
| 470 |
|
---|
| 471 | /*
|
---|
| 472 | * Return true if it is possible (from point of view of range decoder) that
|
---|
| 473 | * we have reached the end of the LZMA chunk.
|
---|
| 474 | */
|
---|
| 475 | static inline bool XZ_FUNC rc_is_finished(const struct rc_dec *rc)
|
---|
| 476 | {
|
---|
| 477 | return rc->code == 0;
|
---|
| 478 | }
|
---|
| 479 |
|
---|
| 480 | /* Read the next input byte if needed. */
|
---|
| 481 | static __always_inline void XZ_FUNC rc_normalize(struct rc_dec *rc)
|
---|
| 482 | {
|
---|
| 483 | if (rc->range < RC_TOP_VALUE) {
|
---|
| 484 | rc->range <<= RC_SHIFT_BITS;
|
---|
| 485 | rc->code = (rc->code << RC_SHIFT_BITS) + rc->in[rc->in_pos++];
|
---|
| 486 | }
|
---|
| 487 | }
|
---|
| 488 |
|
---|
| 489 | /*
|
---|
| 490 | * Decode one bit. In some versions, this function has been splitted in three
|
---|
| 491 | * functions so that the compiler is supposed to be able to more easily avoid
|
---|
| 492 | * an extra branch. In this particular version of the LZMA decoder, this
|
---|
| 493 | * doesn't seem to be a good idea (tested with GCC 3.3.6, 3.4.6, and 4.3.3
|
---|
| 494 | * on x86). Using a non-splitted version results in nicer looking code too.
|
---|
| 495 | *
|
---|
| 496 | * NOTE: This must return an int. Do not make it return a bool or the speed
|
---|
| 497 | * of the code generated by GCC 3.x decreases 10-15 %. (GCC 4.3 doesn't care,
|
---|
| 498 | * and it generates 10-20 % faster code than GCC 3.x from this file anyway.)
|
---|
| 499 | */
|
---|
| 500 | static __always_inline int XZ_FUNC rc_bit(struct rc_dec *rc, uint16_t *prob)
|
---|
| 501 | {
|
---|
| 502 | uint32_t bound;
|
---|
| 503 | int bit;
|
---|
| 504 |
|
---|
| 505 | rc_normalize(rc);
|
---|
| 506 | bound = (rc->range >> RC_BIT_MODEL_TOTAL_BITS) * *prob;
|
---|
| 507 | if (rc->code < bound) {
|
---|
| 508 | rc->range = bound;
|
---|
| 509 | *prob += (RC_BIT_MODEL_TOTAL - *prob) >> RC_MOVE_BITS;
|
---|
| 510 | bit = 0;
|
---|
| 511 | } else {
|
---|
| 512 | rc->range -= bound;
|
---|
| 513 | rc->code -= bound;
|
---|
| 514 | *prob -= *prob >> RC_MOVE_BITS;
|
---|
| 515 | bit = 1;
|
---|
| 516 | }
|
---|
| 517 |
|
---|
| 518 | return bit;
|
---|
| 519 | }
|
---|
| 520 |
|
---|
| 521 | /* Decode a bittree starting from the most significant bit. */
|
---|
| 522 | static __always_inline uint32_t XZ_FUNC rc_bittree(
|
---|
| 523 | struct rc_dec *rc, uint16_t *probs, uint32_t limit)
|
---|
| 524 | {
|
---|
| 525 | uint32_t symbol = 1;
|
---|
| 526 |
|
---|
| 527 | do {
|
---|
| 528 | if (rc_bit(rc, &probs[symbol]))
|
---|
| 529 | symbol = (symbol << 1) + 1;
|
---|
| 530 | else
|
---|
| 531 | symbol <<= 1;
|
---|
| 532 | } while (symbol < limit);
|
---|
| 533 |
|
---|
| 534 | return symbol;
|
---|
| 535 | }
|
---|
| 536 |
|
---|
| 537 | /* Decode a bittree starting from the least significant bit. */
|
---|
| 538 | static __always_inline void XZ_FUNC rc_bittree_reverse(struct rc_dec *rc,
|
---|
| 539 | uint16_t *probs, uint32_t *dest, uint32_t limit)
|
---|
| 540 | {
|
---|
| 541 | uint32_t symbol = 1;
|
---|
| 542 | uint32_t i = 0;
|
---|
| 543 |
|
---|
| 544 | do {
|
---|
| 545 | if (rc_bit(rc, &probs[symbol])) {
|
---|
| 546 | symbol = (symbol << 1) + 1;
|
---|
| 547 | *dest += 1 << i;
|
---|
| 548 | } else {
|
---|
| 549 | symbol <<= 1;
|
---|
| 550 | }
|
---|
| 551 | } while (++i < limit);
|
---|
| 552 | }
|
---|
| 553 |
|
---|
| 554 | /* Decode direct bits (fixed fifty-fifty probability) */
|
---|
| 555 | static inline void XZ_FUNC rc_direct(
|
---|
| 556 | struct rc_dec *rc, uint32_t *dest, uint32_t limit)
|
---|
| 557 | {
|
---|
| 558 | uint32_t mask;
|
---|
| 559 |
|
---|
| 560 | do {
|
---|
| 561 | rc_normalize(rc);
|
---|
| 562 | rc->range >>= 1;
|
---|
| 563 | rc->code -= rc->range;
|
---|
| 564 | mask = (uint32_t)0 - (rc->code >> 31);
|
---|
| 565 | rc->code += rc->range & mask;
|
---|
| 566 | *dest = (*dest << 1) + (mask + 1);
|
---|
| 567 | } while (--limit > 0);
|
---|
| 568 | }
|
---|
| 569 |
|
---|
| 570 | /********
|
---|
| 571 | * LZMA *
|
---|
| 572 | ********/
|
---|
| 573 |
|
---|
| 574 | /* Get pointer to literal coder probability array. */
|
---|
| 575 | static uint16_t * XZ_FUNC lzma_literal_probs(struct xz_dec_lzma2 *s)
|
---|
| 576 | {
|
---|
| 577 | uint32_t prev_byte = dict_get(&s->dict, 0);
|
---|
| 578 | uint32_t low = prev_byte >> (8 - s->lzma.lc);
|
---|
| 579 | uint32_t high = (s->dict.pos & s->lzma.literal_pos_mask) << s->lzma.lc;
|
---|
| 580 | return s->lzma.literal[low + high];
|
---|
| 581 | }
|
---|
| 582 |
|
---|
| 583 | /* Decode a literal (one 8-bit byte) */
|
---|
| 584 | static void XZ_FUNC lzma_literal(struct xz_dec_lzma2 *s)
|
---|
| 585 | {
|
---|
| 586 | uint16_t *probs;
|
---|
| 587 | uint32_t symbol;
|
---|
| 588 | uint32_t match_byte;
|
---|
| 589 | uint32_t match_bit;
|
---|
| 590 | uint32_t offset;
|
---|
| 591 | uint32_t i;
|
---|
| 592 |
|
---|
| 593 | probs = lzma_literal_probs(s);
|
---|
| 594 |
|
---|
| 595 | if (lzma_state_is_literal(s->lzma.state)) {
|
---|
| 596 | symbol = rc_bittree(&s->rc, probs, 0x100);
|
---|
| 597 | } else {
|
---|
| 598 | symbol = 1;
|
---|
| 599 | match_byte = dict_get(&s->dict, s->lzma.rep0) << 1;
|
---|
| 600 | offset = 0x100;
|
---|
| 601 |
|
---|
| 602 | do {
|
---|
| 603 | match_bit = match_byte & offset;
|
---|
| 604 | match_byte <<= 1;
|
---|
| 605 | i = offset + match_bit + symbol;
|
---|
| 606 |
|
---|
| 607 | if (rc_bit(&s->rc, &probs[i])) {
|
---|
| 608 | symbol = (symbol << 1) + 1;
|
---|
| 609 | offset &= match_bit;
|
---|
| 610 | } else {
|
---|
| 611 | symbol <<= 1;
|
---|
| 612 | offset &= ~match_bit;
|
---|
| 613 | }
|
---|
| 614 | } while (symbol < 0x100);
|
---|
| 615 | }
|
---|
| 616 |
|
---|
| 617 | dict_put(&s->dict, (uint8_t)symbol);
|
---|
| 618 | lzma_state_literal(&s->lzma.state);
|
---|
| 619 | }
|
---|
| 620 |
|
---|
| 621 | /* Decode the length of the match into s->lzma.len. */
|
---|
| 622 | static void XZ_FUNC lzma_len(struct xz_dec_lzma2 *s, struct lzma_len_dec *l,
|
---|
| 623 | uint32_t pos_state)
|
---|
| 624 | {
|
---|
| 625 | uint16_t *probs;
|
---|
| 626 | uint32_t limit;
|
---|
| 627 |
|
---|
| 628 | if (!rc_bit(&s->rc, &l->choice)) {
|
---|
| 629 | probs = l->low[pos_state];
|
---|
| 630 | limit = LEN_LOW_SYMBOLS;
|
---|
| 631 | s->lzma.len = MATCH_LEN_MIN;
|
---|
| 632 | } else {
|
---|
| 633 | if (!rc_bit(&s->rc, &l->choice2)) {
|
---|
| 634 | probs = l->mid[pos_state];
|
---|
| 635 | limit = LEN_MID_SYMBOLS;
|
---|
| 636 | s->lzma.len = MATCH_LEN_MIN + LEN_LOW_SYMBOLS;
|
---|
| 637 | } else {
|
---|
| 638 | probs = l->high;
|
---|
| 639 | limit = LEN_HIGH_SYMBOLS;
|
---|
| 640 | s->lzma.len = MATCH_LEN_MIN + LEN_LOW_SYMBOLS
|
---|
| 641 | + LEN_MID_SYMBOLS;
|
---|
| 642 | }
|
---|
| 643 | }
|
---|
| 644 |
|
---|
| 645 | s->lzma.len += rc_bittree(&s->rc, probs, limit) - limit;
|
---|
| 646 | }
|
---|
| 647 |
|
---|
| 648 | /* Decode a match. The distance will be stored in s->lzma.rep0. */
|
---|
| 649 | static void XZ_FUNC lzma_match(struct xz_dec_lzma2 *s, uint32_t pos_state)
|
---|
| 650 | {
|
---|
| 651 | uint16_t *probs;
|
---|
| 652 | uint32_t dist_slot;
|
---|
| 653 | uint32_t limit;
|
---|
| 654 |
|
---|
| 655 | lzma_state_match(&s->lzma.state);
|
---|
| 656 |
|
---|
| 657 | s->lzma.rep3 = s->lzma.rep2;
|
---|
| 658 | s->lzma.rep2 = s->lzma.rep1;
|
---|
| 659 | s->lzma.rep1 = s->lzma.rep0;
|
---|
| 660 |
|
---|
| 661 | lzma_len(s, &s->lzma.match_len_dec, pos_state);
|
---|
| 662 |
|
---|
| 663 | probs = s->lzma.dist_slot[lzma_get_dist_state(s->lzma.len)];
|
---|
| 664 | dist_slot = rc_bittree(&s->rc, probs, DIST_SLOTS) - DIST_SLOTS;
|
---|
| 665 |
|
---|
| 666 | if (dist_slot < DIST_MODEL_START) {
|
---|
| 667 | s->lzma.rep0 = dist_slot;
|
---|
| 668 | } else {
|
---|
| 669 | limit = (dist_slot >> 1) - 1;
|
---|
| 670 | s->lzma.rep0 = 2 + (dist_slot & 1);
|
---|
| 671 |
|
---|
| 672 | if (dist_slot < DIST_MODEL_END) {
|
---|
| 673 | s->lzma.rep0 <<= limit;
|
---|
| 674 | probs = s->lzma.dist_special + s->lzma.rep0
|
---|
| 675 | - dist_slot - 1;
|
---|
| 676 | rc_bittree_reverse(&s->rc, probs,
|
---|
| 677 | &s->lzma.rep0, limit);
|
---|
| 678 | } else {
|
---|
| 679 | rc_direct(&s->rc, &s->lzma.rep0, limit - ALIGN_BITS);
|
---|
| 680 | s->lzma.rep0 <<= ALIGN_BITS;
|
---|
| 681 | rc_bittree_reverse(&s->rc, s->lzma.dist_align,
|
---|
| 682 | &s->lzma.rep0, ALIGN_BITS);
|
---|
| 683 | }
|
---|
| 684 | }
|
---|
| 685 | }
|
---|
| 686 |
|
---|
| 687 | /*
|
---|
| 688 | * Decode a repeated match. The distance is one of the four most recently
|
---|
| 689 | * seen matches. The distance will be stored in s->lzma.rep0.
|
---|
| 690 | */
|
---|
| 691 | static void XZ_FUNC lzma_rep_match(struct xz_dec_lzma2 *s, uint32_t pos_state)
|
---|
| 692 | {
|
---|
| 693 | uint32_t tmp;
|
---|
| 694 |
|
---|
| 695 | if (!rc_bit(&s->rc, &s->lzma.is_rep0[s->lzma.state])) {
|
---|
| 696 | if (!rc_bit(&s->rc, &s->lzma.is_rep0_long[
|
---|
| 697 | s->lzma.state][pos_state])) {
|
---|
| 698 | lzma_state_short_rep(&s->lzma.state);
|
---|
| 699 | s->lzma.len = 1;
|
---|
| 700 | return;
|
---|
| 701 | }
|
---|
| 702 | } else {
|
---|
| 703 | if (!rc_bit(&s->rc, &s->lzma.is_rep1[s->lzma.state])) {
|
---|
| 704 | tmp = s->lzma.rep1;
|
---|
| 705 | } else {
|
---|
| 706 | if (!rc_bit(&s->rc, &s->lzma.is_rep2[s->lzma.state])) {
|
---|
| 707 | tmp = s->lzma.rep2;
|
---|
| 708 | } else {
|
---|
| 709 | tmp = s->lzma.rep3;
|
---|
| 710 | s->lzma.rep3 = s->lzma.rep2;
|
---|
| 711 | }
|
---|
| 712 |
|
---|
| 713 | s->lzma.rep2 = s->lzma.rep1;
|
---|
| 714 | }
|
---|
| 715 |
|
---|
| 716 | s->lzma.rep1 = s->lzma.rep0;
|
---|
| 717 | s->lzma.rep0 = tmp;
|
---|
| 718 | }
|
---|
| 719 |
|
---|
| 720 | lzma_state_long_rep(&s->lzma.state);
|
---|
| 721 | lzma_len(s, &s->lzma.rep_len_dec, pos_state);
|
---|
| 722 | }
|
---|
| 723 |
|
---|
| 724 | /* LZMA decoder core */
|
---|
| 725 | static bool XZ_FUNC lzma_main(struct xz_dec_lzma2 *s)
|
---|
| 726 | {
|
---|
| 727 | uint32_t pos_state;
|
---|
| 728 |
|
---|
| 729 | /*
|
---|
| 730 | * If the dictionary was reached during the previous call, try to
|
---|
| 731 | * finish the possibly pending repeat in the dictionary.
|
---|
| 732 | */
|
---|
| 733 | if (dict_has_space(&s->dict) && s->lzma.len > 0)
|
---|
| 734 | dict_repeat(&s->dict, &s->lzma.len, s->lzma.rep0);
|
---|
| 735 |
|
---|
| 736 | /*
|
---|
| 737 | * Decode more LZMA symbols. One iteration may consume up to
|
---|
| 738 | * LZMA_IN_REQUIRED - 1 bytes.
|
---|
| 739 | */
|
---|
| 740 | while (dict_has_space(&s->dict) && !rc_limit_exceeded(&s->rc)) {
|
---|
| 741 | pos_state = s->dict.pos & s->lzma.pos_mask;
|
---|
| 742 |
|
---|
| 743 | if (!rc_bit(&s->rc, &s->lzma.is_match[
|
---|
| 744 | s->lzma.state][pos_state])) {
|
---|
| 745 | lzma_literal(s);
|
---|
| 746 | } else {
|
---|
| 747 | if (rc_bit(&s->rc, &s->lzma.is_rep[s->lzma.state]))
|
---|
| 748 | lzma_rep_match(s, pos_state);
|
---|
| 749 | else
|
---|
| 750 | lzma_match(s, pos_state);
|
---|
| 751 |
|
---|
| 752 | if (!dict_repeat(&s->dict, &s->lzma.len, s->lzma.rep0))
|
---|
| 753 | return false;
|
---|
| 754 | }
|
---|
| 755 | }
|
---|
| 756 |
|
---|
| 757 | /*
|
---|
| 758 | * Having the range decoder always normalized when we are outside
|
---|
| 759 | * this function makes it easier to correctly handle end of the chunk.
|
---|
| 760 | */
|
---|
| 761 | rc_normalize(&s->rc);
|
---|
| 762 |
|
---|
| 763 | return true;
|
---|
| 764 | }
|
---|
| 765 |
|
---|
| 766 | /*
|
---|
| 767 | * Reset the LZMA decoder and range decoder state. Dictionary is nore reset
|
---|
| 768 | * here, because LZMA state may be reset without resetting the dictionary.
|
---|
| 769 | */
|
---|
| 770 | static void XZ_FUNC lzma_reset(struct xz_dec_lzma2 *s)
|
---|
| 771 | {
|
---|
| 772 | uint16_t *probs;
|
---|
| 773 | size_t i;
|
---|
| 774 |
|
---|
| 775 | s->lzma.state = STATE_LIT_LIT;
|
---|
| 776 | s->lzma.rep0 = 0;
|
---|
| 777 | s->lzma.rep1 = 0;
|
---|
| 778 | s->lzma.rep2 = 0;
|
---|
| 779 | s->lzma.rep3 = 0;
|
---|
| 780 |
|
---|
| 781 | /*
|
---|
| 782 | * All probabilities are initialized to the same value. This hack
|
---|
| 783 | * makes the code smaller by avoiding a separate loop for each
|
---|
| 784 | * probability array.
|
---|
| 785 | *
|
---|
| 786 | * This could be optimized so that only that part of literal
|
---|
| 787 | * probabilities that are actually required. In the common case
|
---|
| 788 | * we would write 12 KiB less.
|
---|
| 789 | */
|
---|
| 790 | probs = s->lzma.is_match[0];
|
---|
| 791 | for (i = 0; i < PROBS_TOTAL; ++i)
|
---|
| 792 | probs[i] = RC_BIT_MODEL_TOTAL / 2;
|
---|
| 793 |
|
---|
| 794 | rc_reset(&s->rc);
|
---|
| 795 | }
|
---|
| 796 |
|
---|
| 797 | /*
|
---|
| 798 | * Decode and validate LZMA properties (lc/lp/pb) and calculate the bit masks
|
---|
| 799 | * from the decoded lp and pb values. On success, the LZMA decoder state is
|
---|
| 800 | * reset and true is returned.
|
---|
| 801 | */
|
---|
| 802 | static bool XZ_FUNC lzma_props(struct xz_dec_lzma2 *s, uint8_t props)
|
---|
| 803 | {
|
---|
| 804 | if (props > (4 * 5 + 4) * 9 + 8)
|
---|
| 805 | return false;
|
---|
| 806 |
|
---|
| 807 | s->lzma.pos_mask = 0;
|
---|
| 808 | while (props >= 9 * 5) {
|
---|
| 809 | props -= 9 * 5;
|
---|
| 810 | ++s->lzma.pos_mask;
|
---|
| 811 | }
|
---|
| 812 |
|
---|
| 813 | s->lzma.pos_mask = (1 << s->lzma.pos_mask) - 1;
|
---|
| 814 |
|
---|
| 815 | s->lzma.literal_pos_mask = 0;
|
---|
| 816 | while (props >= 9) {
|
---|
| 817 | props -= 9;
|
---|
| 818 | ++s->lzma.literal_pos_mask;
|
---|
| 819 | }
|
---|
| 820 |
|
---|
| 821 | s->lzma.lc = props;
|
---|
| 822 |
|
---|
| 823 | if (s->lzma.lc + s->lzma.literal_pos_mask > 4)
|
---|
| 824 | return false;
|
---|
| 825 |
|
---|
| 826 | s->lzma.literal_pos_mask = (1 << s->lzma.literal_pos_mask) - 1;
|
---|
| 827 |
|
---|
| 828 | lzma_reset(s);
|
---|
| 829 |
|
---|
| 830 | return true;
|
---|
| 831 | }
|
---|
| 832 |
|
---|
| 833 | /*********
|
---|
| 834 | * LZMA2 *
|
---|
| 835 | *********/
|
---|
| 836 |
|
---|
| 837 | /*
|
---|
| 838 | * The LZMA decoder assumes that if the input limit (s->rc.in_limit) hasn't
|
---|
| 839 | * been exceeded, it is safe to read up to LZMA_IN_REQUIRED bytes. This
|
---|
| 840 | * wrapper function takes care of making the LZMA decoder's assumption safe.
|
---|
| 841 | *
|
---|
| 842 | * As long as there is plenty of input left to be decoded in the current LZMA
|
---|
| 843 | * chunk, we decode directly from the caller-supplied input buffer until
|
---|
| 844 | * there's LZMA_IN_REQUIRED bytes left. Those remaining bytes are copied into
|
---|
| 845 | * s->temp.buf, which (hopefully) gets filled on the next call to this
|
---|
| 846 | * function. We decode a few bytes from the temporary buffer so that we can
|
---|
| 847 | * continue decoding from the caller-supplied input buffer again.
|
---|
| 848 | */
|
---|
| 849 | static bool XZ_FUNC lzma2_lzma(struct xz_dec_lzma2 *s, struct xz_buf *b)
|
---|
| 850 | {
|
---|
| 851 | size_t in_avail;
|
---|
| 852 | uint32_t tmp;
|
---|
| 853 |
|
---|
| 854 | in_avail = b->in_size - b->in_pos;
|
---|
| 855 | if (s->temp.size > 0 || s->lzma2.compressed == 0) {
|
---|
| 856 | tmp = 2 * LZMA_IN_REQUIRED - s->temp.size;
|
---|
| 857 | if (tmp > s->lzma2.compressed - s->temp.size)
|
---|
| 858 | tmp = s->lzma2.compressed - s->temp.size;
|
---|
| 859 | if (tmp > in_avail)
|
---|
| 860 | tmp = in_avail;
|
---|
| 861 |
|
---|
| 862 | memcpy(s->temp.buf + s->temp.size, b->in + b->in_pos, tmp);
|
---|
| 863 |
|
---|
| 864 | if (s->temp.size + tmp == s->lzma2.compressed) {
|
---|
| 865 | memzero(s->temp.buf + s->temp.size + tmp,
|
---|
| 866 | sizeof(s->temp.buf)
|
---|
| 867 | - s->temp.size - tmp);
|
---|
| 868 | s->rc.in_limit = s->temp.size + tmp;
|
---|
| 869 | } else if (s->temp.size + tmp < LZMA_IN_REQUIRED) {
|
---|
| 870 | s->temp.size += tmp;
|
---|
| 871 | b->in_pos += tmp;
|
---|
| 872 | return true;
|
---|
| 873 | } else {
|
---|
| 874 | s->rc.in_limit = s->temp.size + tmp - LZMA_IN_REQUIRED;
|
---|
| 875 | }
|
---|
| 876 |
|
---|
| 877 | s->rc.in = s->temp.buf;
|
---|
| 878 | s->rc.in_pos = 0;
|
---|
| 879 |
|
---|
| 880 | if (!lzma_main(s) || s->rc.in_pos > s->temp.size + tmp)
|
---|
| 881 | return false;
|
---|
| 882 |
|
---|
| 883 | s->lzma2.compressed -= s->rc.in_pos;
|
---|
| 884 |
|
---|
| 885 | if (s->rc.in_pos < s->temp.size) {
|
---|
| 886 | s->temp.size -= s->rc.in_pos;
|
---|
| 887 | memmove(s->temp.buf, s->temp.buf + s->rc.in_pos,
|
---|
| 888 | s->temp.size);
|
---|
| 889 | return true;
|
---|
| 890 | }
|
---|
| 891 |
|
---|
| 892 | b->in_pos += s->rc.in_pos - s->temp.size;
|
---|
| 893 | s->temp.size = 0;
|
---|
| 894 | }
|
---|
| 895 |
|
---|
| 896 | in_avail = b->in_size - b->in_pos;
|
---|
| 897 | if (in_avail >= LZMA_IN_REQUIRED) {
|
---|
| 898 | s->rc.in = b->in;
|
---|
| 899 | s->rc.in_pos = b->in_pos;
|
---|
| 900 |
|
---|
| 901 | if (in_avail >= s->lzma2.compressed + LZMA_IN_REQUIRED)
|
---|
| 902 | s->rc.in_limit = b->in_pos + s->lzma2.compressed;
|
---|
| 903 | else
|
---|
| 904 | s->rc.in_limit = b->in_size - LZMA_IN_REQUIRED;
|
---|
| 905 |
|
---|
| 906 | if (!lzma_main(s))
|
---|
| 907 | return false;
|
---|
| 908 |
|
---|
| 909 | in_avail = s->rc.in_pos - b->in_pos;
|
---|
| 910 | if (in_avail > s->lzma2.compressed)
|
---|
| 911 | return false;
|
---|
| 912 |
|
---|
| 913 | s->lzma2.compressed -= in_avail;
|
---|
| 914 | b->in_pos = s->rc.in_pos;
|
---|
| 915 | }
|
---|
| 916 |
|
---|
| 917 | in_avail = b->in_size - b->in_pos;
|
---|
| 918 | if (in_avail < LZMA_IN_REQUIRED) {
|
---|
| 919 | if (in_avail > s->lzma2.compressed)
|
---|
| 920 | in_avail = s->lzma2.compressed;
|
---|
| 921 |
|
---|
| 922 | memcpy(s->temp.buf, b->in + b->in_pos, in_avail);
|
---|
| 923 | s->temp.size = in_avail;
|
---|
| 924 | b->in_pos += in_avail;
|
---|
| 925 | }
|
---|
| 926 |
|
---|
| 927 | return true;
|
---|
| 928 | }
|
---|
| 929 |
|
---|
| 930 | /*
|
---|
| 931 | * Take care of the LZMA2 control layer, and forward the job of actual LZMA
|
---|
| 932 | * decoding or copying of uncompressed chunks to other functions.
|
---|
| 933 | */
|
---|
| 934 | XZ_EXTERN NOINLINE enum xz_ret XZ_FUNC xz_dec_lzma2_run(
|
---|
| 935 | struct xz_dec_lzma2 *s, struct xz_buf *b)
|
---|
| 936 | {
|
---|
| 937 | uint32_t tmp;
|
---|
| 938 |
|
---|
| 939 | while (b->in_pos < b->in_size || s->lzma2.sequence == SEQ_LZMA_RUN) {
|
---|
| 940 | switch (s->lzma2.sequence) {
|
---|
| 941 | case SEQ_CONTROL:
|
---|
| 942 | /*
|
---|
| 943 | * LZMA2 control byte
|
---|
| 944 | *
|
---|
| 945 | * Exact values:
|
---|
| 946 | * 0x00 End marker
|
---|
| 947 | * 0x01 Dictionary reset followed by
|
---|
| 948 | * an uncompressed chunk
|
---|
| 949 | * 0x02 Uncompressed chunk (no dictionary reset)
|
---|
| 950 | *
|
---|
| 951 | * Highest three bits (s->control & 0xE0):
|
---|
| 952 | * 0xE0 Dictionary reset, new properties and state
|
---|
| 953 | * reset, followed by LZMA compressed chunk
|
---|
| 954 | * 0xC0 New properties and state reset, followed
|
---|
| 955 | * by LZMA compressed chunk (no dictionary
|
---|
| 956 | * reset)
|
---|
| 957 | * 0xA0 State reset using old properties,
|
---|
| 958 | * followed by LZMA compressed chunk (no
|
---|
| 959 | * dictionary reset)
|
---|
| 960 | * 0x80 LZMA chunk (no dictionary or state reset)
|
---|
| 961 | *
|
---|
| 962 | * For LZMA compressed chunks, the lowest five bits
|
---|
| 963 | * (s->control & 1F) are the highest bits of the
|
---|
| 964 | * uncompressed size (bits 16-20).
|
---|
| 965 | *
|
---|
| 966 | * A new LZMA2 stream must begin with a dictionary
|
---|
| 967 | * reset. The first LZMA chunk must set new
|
---|
| 968 | * properties and reset the LZMA state.
|
---|
| 969 | *
|
---|
| 970 | * Values that don't match anything described above
|
---|
| 971 | * are invalid and we return XZ_DATA_ERROR.
|
---|
| 972 | */
|
---|
| 973 | tmp = b->in[b->in_pos++];
|
---|
| 974 |
|
---|
| 975 | if (tmp >= 0xE0 || tmp == 0x01) {
|
---|
| 976 | s->lzma2.need_props = true;
|
---|
| 977 | s->lzma2.need_dict_reset = false;
|
---|
| 978 | dict_reset(&s->dict, b);
|
---|
| 979 | } else if (s->lzma2.need_dict_reset) {
|
---|
| 980 | return XZ_DATA_ERROR;
|
---|
| 981 | }
|
---|
| 982 |
|
---|
| 983 | if (tmp >= 0x80) {
|
---|
| 984 | s->lzma2.uncompressed = (tmp & 0x1F) << 16;
|
---|
| 985 | s->lzma2.sequence = SEQ_UNCOMPRESSED_1;
|
---|
| 986 |
|
---|
| 987 | if (tmp >= 0xC0) {
|
---|
| 988 | /*
|
---|
| 989 | * When there are new properties,
|
---|
| 990 | * state reset is done at
|
---|
| 991 | * SEQ_PROPERTIES.
|
---|
| 992 | */
|
---|
| 993 | s->lzma2.need_props = false;
|
---|
| 994 | s->lzma2.next_sequence
|
---|
| 995 | = SEQ_PROPERTIES;
|
---|
| 996 |
|
---|
| 997 | } else if (s->lzma2.need_props) {
|
---|
| 998 | return XZ_DATA_ERROR;
|
---|
| 999 |
|
---|
| 1000 | } else {
|
---|
| 1001 | s->lzma2.next_sequence
|
---|
| 1002 | = SEQ_LZMA_PREPARE;
|
---|
| 1003 | if (tmp >= 0xA0)
|
---|
| 1004 | lzma_reset(s);
|
---|
| 1005 | }
|
---|
| 1006 | } else {
|
---|
| 1007 | if (tmp == 0x00)
|
---|
| 1008 | return XZ_STREAM_END;
|
---|
| 1009 |
|
---|
| 1010 | if (tmp > 0x02)
|
---|
| 1011 | return XZ_DATA_ERROR;
|
---|
| 1012 |
|
---|
| 1013 | s->lzma2.sequence = SEQ_COMPRESSED_0;
|
---|
| 1014 | s->lzma2.next_sequence = SEQ_COPY;
|
---|
| 1015 | }
|
---|
| 1016 |
|
---|
| 1017 | break;
|
---|
| 1018 |
|
---|
| 1019 | case SEQ_UNCOMPRESSED_1:
|
---|
| 1020 | s->lzma2.uncompressed
|
---|
| 1021 | += (uint32_t)b->in[b->in_pos++] << 8;
|
---|
| 1022 | s->lzma2.sequence = SEQ_UNCOMPRESSED_2;
|
---|
| 1023 | break;
|
---|
| 1024 |
|
---|
| 1025 | case SEQ_UNCOMPRESSED_2:
|
---|
| 1026 | s->lzma2.uncompressed
|
---|
| 1027 | += (uint32_t)b->in[b->in_pos++] + 1;
|
---|
| 1028 | s->lzma2.sequence = SEQ_COMPRESSED_0;
|
---|
| 1029 | break;
|
---|
| 1030 |
|
---|
| 1031 | case SEQ_COMPRESSED_0:
|
---|
| 1032 | s->lzma2.compressed
|
---|
| 1033 | = (uint32_t)b->in[b->in_pos++] << 8;
|
---|
| 1034 | s->lzma2.sequence = SEQ_COMPRESSED_1;
|
---|
| 1035 | break;
|
---|
| 1036 |
|
---|
| 1037 | case SEQ_COMPRESSED_1:
|
---|
| 1038 | s->lzma2.compressed
|
---|
| 1039 | += (uint32_t)b->in[b->in_pos++] + 1;
|
---|
| 1040 | s->lzma2.sequence = s->lzma2.next_sequence;
|
---|
| 1041 | break;
|
---|
| 1042 |
|
---|
| 1043 | case SEQ_PROPERTIES:
|
---|
| 1044 | if (!lzma_props(s, b->in[b->in_pos++]))
|
---|
| 1045 | return XZ_DATA_ERROR;
|
---|
| 1046 |
|
---|
| 1047 | s->lzma2.sequence = SEQ_LZMA_PREPARE;
|
---|
| 1048 |
|
---|
| 1049 | case SEQ_LZMA_PREPARE:
|
---|
| 1050 | if (s->lzma2.compressed < RC_INIT_BYTES)
|
---|
| 1051 | return XZ_DATA_ERROR;
|
---|
| 1052 |
|
---|
| 1053 | if (!rc_read_init(&s->rc, b))
|
---|
| 1054 | return XZ_OK;
|
---|
| 1055 |
|
---|
| 1056 | s->lzma2.compressed -= RC_INIT_BYTES;
|
---|
| 1057 | s->lzma2.sequence = SEQ_LZMA_RUN;
|
---|
| 1058 |
|
---|
| 1059 | case SEQ_LZMA_RUN:
|
---|
| 1060 | /*
|
---|
| 1061 | * Set dictionary limit to indicate how much we want
|
---|
| 1062 | * to be encoded at maximum. Decode new data into the
|
---|
| 1063 | * dictionary. Flush the new data from dictionary to
|
---|
| 1064 | * b->out. Check if we finished decoding this chunk.
|
---|
| 1065 | * In case the dictionary got full but we didn't fill
|
---|
| 1066 | * the output buffer yet, we may run this loop
|
---|
| 1067 | * multiple times without changing s->lzma2.sequence.
|
---|
| 1068 | */
|
---|
| 1069 | dict_limit(&s->dict, min_t(size_t,
|
---|
| 1070 | b->out_size - b->out_pos,
|
---|
| 1071 | s->lzma2.uncompressed));
|
---|
| 1072 | if (!lzma2_lzma(s, b))
|
---|
| 1073 | return XZ_DATA_ERROR;
|
---|
| 1074 |
|
---|
| 1075 | s->lzma2.uncompressed -= dict_flush(&s->dict, b);
|
---|
| 1076 |
|
---|
| 1077 | if (s->lzma2.uncompressed == 0) {
|
---|
| 1078 | if (s->lzma2.compressed > 0 || s->lzma.len > 0
|
---|
| 1079 | || !rc_is_finished(&s->rc))
|
---|
| 1080 | return XZ_DATA_ERROR;
|
---|
| 1081 |
|
---|
| 1082 | rc_reset(&s->rc);
|
---|
| 1083 | s->lzma2.sequence = SEQ_CONTROL;
|
---|
| 1084 |
|
---|
| 1085 | } else if (b->out_pos == b->out_size
|
---|
| 1086 | || (b->in_pos == b->in_size
|
---|
| 1087 | && s->temp.size
|
---|
| 1088 | < s->lzma2.compressed)) {
|
---|
| 1089 | return XZ_OK;
|
---|
| 1090 | }
|
---|
| 1091 |
|
---|
| 1092 | break;
|
---|
| 1093 |
|
---|
| 1094 | case SEQ_COPY:
|
---|
| 1095 | dict_uncompressed(&s->dict, b, &s->lzma2.compressed);
|
---|
| 1096 | if (s->lzma2.compressed > 0)
|
---|
| 1097 | return XZ_OK;
|
---|
| 1098 |
|
---|
| 1099 | s->lzma2.sequence = SEQ_CONTROL;
|
---|
| 1100 | break;
|
---|
| 1101 | }
|
---|
| 1102 | }
|
---|
| 1103 |
|
---|
| 1104 | return XZ_OK;
|
---|
| 1105 | }
|
---|
| 1106 |
|
---|
| 1107 | XZ_EXTERN struct xz_dec_lzma2 * XZ_FUNC xz_dec_lzma2_create(
|
---|
| 1108 | enum xz_mode mode, uint32_t dict_max)
|
---|
| 1109 | {
|
---|
| 1110 | struct xz_dec_lzma2 *s = kmalloc(sizeof(*s), GFP_KERNEL);
|
---|
| 1111 | if (s == NULL)
|
---|
| 1112 | return NULL;
|
---|
| 1113 |
|
---|
| 1114 | s->dict.mode = mode;
|
---|
| 1115 | s->dict.size_max = dict_max;
|
---|
| 1116 |
|
---|
| 1117 | if (DEC_IS_PREALLOC(mode)) {
|
---|
| 1118 | s->dict.buf = vmalloc(dict_max);
|
---|
| 1119 | if (s->dict.buf == NULL) {
|
---|
| 1120 | kfree(s);
|
---|
| 1121 | return NULL;
|
---|
| 1122 | }
|
---|
| 1123 | } else if (DEC_IS_DYNALLOC(mode)) {
|
---|
| 1124 | s->dict.buf = NULL;
|
---|
| 1125 | s->dict.allocated = 0;
|
---|
| 1126 | }
|
---|
| 1127 |
|
---|
| 1128 | return s;
|
---|
| 1129 | }
|
---|
| 1130 |
|
---|
| 1131 | XZ_EXTERN enum xz_ret XZ_FUNC xz_dec_lzma2_reset(
|
---|
| 1132 | struct xz_dec_lzma2 *s, uint8_t props)
|
---|
| 1133 | {
|
---|
| 1134 | /* This limits dictionary size to 3 GiB to keep parsing simpler. */
|
---|
| 1135 | if (props > 39)
|
---|
| 1136 | return XZ_OPTIONS_ERROR;
|
---|
| 1137 |
|
---|
| 1138 | s->dict.size = 2 + (props & 1);
|
---|
| 1139 | s->dict.size <<= (props >> 1) + 11;
|
---|
| 1140 |
|
---|
| 1141 | if (DEC_IS_MULTI(s->dict.mode)) {
|
---|
| 1142 | if (s->dict.size > s->dict.size_max)
|
---|
| 1143 | return XZ_MEMLIMIT_ERROR;
|
---|
| 1144 |
|
---|
| 1145 | s->dict.end = s->dict.size;
|
---|
| 1146 |
|
---|
| 1147 | if (DEC_IS_DYNALLOC(s->dict.mode)) {
|
---|
| 1148 | if (s->dict.allocated < s->dict.size) {
|
---|
| 1149 | vfree(s->dict.buf);
|
---|
| 1150 | s->dict.buf = vmalloc(s->dict.size);
|
---|
| 1151 | if (s->dict.buf == NULL) {
|
---|
| 1152 | s->dict.allocated = 0;
|
---|
| 1153 | return XZ_MEM_ERROR;
|
---|
| 1154 | }
|
---|
| 1155 | }
|
---|
| 1156 | }
|
---|
| 1157 | }
|
---|
| 1158 |
|
---|
| 1159 | s->lzma.len = 0;
|
---|
| 1160 |
|
---|
| 1161 | s->lzma2.sequence = SEQ_CONTROL;
|
---|
| 1162 | s->lzma2.need_dict_reset = true;
|
---|
| 1163 |
|
---|
| 1164 | s->temp.size = 0;
|
---|
| 1165 |
|
---|
| 1166 | return XZ_OK;
|
---|
| 1167 | }
|
---|
| 1168 |
|
---|
| 1169 | XZ_EXTERN void XZ_FUNC xz_dec_lzma2_end(struct xz_dec_lzma2 *s)
|
---|
| 1170 | {
|
---|
| 1171 | if (DEC_IS_MULTI(s->dict.mode))
|
---|
| 1172 | vfree(s->dict.buf);
|
---|
| 1173 |
|
---|
| 1174 | kfree(s);
|
---|
| 1175 | }
|
---|