| 1 | /* |
| 2 | * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at> |
| 3 | * |
| 4 | * This file is part of FFmpeg. |
| 5 | * |
| 6 | * FFmpeg is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public |
| 8 | * License as published by the Free Software Foundation; either |
| 9 | * version 2.1 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * FFmpeg is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public |
| 17 | * License along with FFmpeg; if not, write to the Free Software |
| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 19 | */ |
| 20 | |
| 21 | /** |
| 22 | * @file |
| 23 | * bitstream reader API header. |
| 24 | */ |
| 25 | |
| 26 | #ifndef AVCODEC_GET_BITS_H |
| 27 | #define AVCODEC_GET_BITS_H |
| 28 | |
| 29 | #include <stdint.h> |
| 30 | |
| 31 | #include "libavutil/common.h" |
| 32 | #include "libavutil/intreadwrite.h" |
| 33 | #include "libavutil/log.h" |
| 34 | #include "libavutil/avassert.h" |
| 35 | #include "mathops.h" |
| 36 | |
| 37 | /* |
| 38 | * Safe bitstream reading: |
| 39 | * optionally, the get_bits API can check to ensure that we |
| 40 | * don't read past input buffer boundaries. This is protected |
| 41 | * with CONFIG_SAFE_BITSTREAM_READER at the global level, and |
| 42 | * then below that with UNCHECKED_BITSTREAM_READER at the per- |
| 43 | * decoder level. This means that decoders that check internally |
| 44 | * can "#define UNCHECKED_BITSTREAM_READER 1" to disable |
| 45 | * overread checks. |
| 46 | * Boundary checking causes a minor performance penalty so for |
| 47 | * applications that won't want/need this, it can be disabled |
| 48 | * globally using "#define CONFIG_SAFE_BITSTREAM_READER 0". |
| 49 | */ |
| 50 | #ifndef UNCHECKED_BITSTREAM_READER |
| 51 | #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER |
| 52 | #endif |
| 53 | |
| 54 | typedef struct GetBitContext { |
| 55 | const uint8_t *buffer, *buffer_end; |
| 56 | int index; |
| 57 | int size_in_bits; |
| 58 | int size_in_bits_plus8; |
| 59 | } GetBitContext; |
| 60 | |
| 61 | #define VLC_TYPE int16_t |
| 62 | |
| 63 | typedef struct VLC { |
| 64 | int bits; |
| 65 | VLC_TYPE (*table)[2]; ///< code, bits |
| 66 | int table_size, table_allocated; |
| 67 | } VLC; |
| 68 | |
| 69 | typedef struct RL_VLC_ELEM { |
| 70 | int16_t level; |
| 71 | int8_t len; |
| 72 | uint8_t run; |
| 73 | } RL_VLC_ELEM; |
| 74 | |
| 75 | /* Bitstream reader API docs: |
| 76 | * name |
| 77 | * arbitrary name which is used as prefix for the internal variables |
| 78 | * |
| 79 | * gb |
| 80 | * getbitcontext |
| 81 | * |
| 82 | * OPEN_READER(name, gb) |
| 83 | * load gb into local variables |
| 84 | * |
| 85 | * CLOSE_READER(name, gb) |
| 86 | * store local vars in gb |
| 87 | * |
| 88 | * UPDATE_CACHE(name, gb) |
| 89 | * Refill the internal cache from the bitstream. |
| 90 | * After this call at least MIN_CACHE_BITS will be available. |
| 91 | * |
| 92 | * GET_CACHE(name, gb) |
| 93 | * Will output the contents of the internal cache, |
| 94 | * next bit is MSB of 32 or 64 bit (FIXME 64bit). |
| 95 | * |
| 96 | * SHOW_UBITS(name, gb, num) |
| 97 | * Will return the next num bits. |
| 98 | * |
| 99 | * SHOW_SBITS(name, gb, num) |
| 100 | * Will return the next num bits and do sign extension. |
| 101 | * |
| 102 | * SKIP_BITS(name, gb, num) |
| 103 | * Will skip over the next num bits. |
| 104 | * Note, this is equivalent to SKIP_CACHE; SKIP_COUNTER. |
| 105 | * |
| 106 | * SKIP_CACHE(name, gb, num) |
| 107 | * Will remove the next num bits from the cache (note SKIP_COUNTER |
| 108 | * MUST be called before UPDATE_CACHE / CLOSE_READER). |
| 109 | * |
| 110 | * SKIP_COUNTER(name, gb, num) |
| 111 | * Will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS). |
| 112 | * |
| 113 | * LAST_SKIP_BITS(name, gb, num) |
| 114 | * Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER. |
| 115 | * |
| 116 | * BITS_LEFT(name, gb) |
| 117 | * Return the number of bits left |
| 118 | * |
| 119 | * For examples see get_bits, show_bits, skip_bits, get_vlc. |
| 120 | */ |
| 121 | |
| 122 | #ifdef LONG_BITSTREAM_READER |
| 123 | # define MIN_CACHE_BITS 32 |
| 124 | #else |
| 125 | # define MIN_CACHE_BITS 25 |
| 126 | #endif |
| 127 | |
| 128 | #define OPEN_READER_NOSIZE(name, gb) \ |
| 129 | unsigned int name ## _index = (gb)->index; \ |
| 130 | unsigned int av_unused name ## _cache |
| 131 | |
| 132 | #if UNCHECKED_BITSTREAM_READER |
| 133 | #define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb) |
| 134 | |
| 135 | #define BITS_AVAILABLE(name, gb) 1 |
| 136 | #else |
| 137 | #define OPEN_READER(name, gb) \ |
| 138 | OPEN_READER_NOSIZE(name, gb); \ |
| 139 | unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8 |
| 140 | |
| 141 | #define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8 |
| 142 | #endif |
| 143 | |
| 144 | #define CLOSE_READER(name, gb) (gb)->index = name ## _index |
| 145 | |
| 146 | # ifdef LONG_BITSTREAM_READER |
| 147 | |
| 148 | # define UPDATE_CACHE_LE(name, gb) name ## _cache = \ |
| 149 | AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7) |
| 150 | |
| 151 | # define UPDATE_CACHE_BE(name, gb) name ## _cache = \ |
| 152 | AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7)) |
| 153 | |
| 154 | #else |
| 155 | |
| 156 | # define UPDATE_CACHE_LE(name, gb) name ## _cache = \ |
| 157 | AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7) |
| 158 | |
| 159 | # define UPDATE_CACHE_BE(name, gb) name ## _cache = \ |
| 160 | AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7) |
| 161 | |
| 162 | #endif |
| 163 | |
| 164 | |
| 165 | #ifdef BITSTREAM_READER_LE |
| 166 | |
| 167 | # define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb) |
| 168 | |
| 169 | # define SKIP_CACHE(name, gb, num) name ## _cache >>= (num) |
| 170 | |
| 171 | #else |
| 172 | |
| 173 | # define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb) |
| 174 | |
| 175 | # define SKIP_CACHE(name, gb, num) name ## _cache <<= (num) |
| 176 | |
| 177 | #endif |
| 178 | |
| 179 | #if UNCHECKED_BITSTREAM_READER |
| 180 | # define SKIP_COUNTER(name, gb, num) name ## _index += (num) |
| 181 | #else |
| 182 | # define SKIP_COUNTER(name, gb, num) \ |
| 183 | name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num)) |
| 184 | #endif |
| 185 | |
| 186 | #define BITS_LEFT(name, gb) ((int)((gb)->size_in_bits - name ## _index)) |
| 187 | |
| 188 | #define SKIP_BITS(name, gb, num) \ |
| 189 | do { \ |
| 190 | SKIP_CACHE(name, gb, num); \ |
| 191 | SKIP_COUNTER(name, gb, num); \ |
| 192 | } while (0) |
| 193 | |
| 194 | #define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num) |
| 195 | |
| 196 | #define SHOW_UBITS_LE(name, gb, num) zero_extend(name ## _cache, num) |
| 197 | #define SHOW_SBITS_LE(name, gb, num) sign_extend(name ## _cache, num) |
| 198 | |
| 199 | #define SHOW_UBITS_BE(name, gb, num) NEG_USR32(name ## _cache, num) |
| 200 | #define SHOW_SBITS_BE(name, gb, num) NEG_SSR32(name ## _cache, num) |
| 201 | |
| 202 | #ifdef BITSTREAM_READER_LE |
| 203 | # define SHOW_UBITS(name, gb, num) SHOW_UBITS_LE(name, gb, num) |
| 204 | # define SHOW_SBITS(name, gb, num) SHOW_SBITS_LE(name, gb, num) |
| 205 | #else |
| 206 | # define SHOW_UBITS(name, gb, num) SHOW_UBITS_BE(name, gb, num) |
| 207 | # define SHOW_SBITS(name, gb, num) SHOW_SBITS_BE(name, gb, num) |
| 208 | #endif |
| 209 | |
| 210 | #define GET_CACHE(name, gb) ((uint32_t) name ## _cache) |
| 211 | |
| 212 | static inline int get_bits_count(const GetBitContext *s) |
| 213 | { |
| 214 | return s->index; |
| 215 | } |
| 216 | |
| 217 | static inline void skip_bits_long(GetBitContext *s, int n) |
| 218 | { |
| 219 | #if UNCHECKED_BITSTREAM_READER |
| 220 | s->index += n; |
| 221 | #else |
| 222 | s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index); |
| 223 | #endif |
| 224 | } |
| 225 | |
| 226 | /** |
| 227 | * read mpeg1 dc style vlc (sign bit + mantissa with no MSB). |
| 228 | * if MSB not set it is negative |
| 229 | * @param n length in bits |
| 230 | */ |
| 231 | static inline int get_xbits(GetBitContext *s, int n) |
| 232 | { |
| 233 | register int sign; |
| 234 | register int32_t cache; |
| 235 | OPEN_READER(re, s); |
| 236 | av_assert2(n>0 && n<=25); |
| 237 | UPDATE_CACHE(re, s); |
| 238 | cache = GET_CACHE(re, s); |
| 239 | sign = ~cache >> 31; |
| 240 | LAST_SKIP_BITS(re, s, n); |
| 241 | CLOSE_READER(re, s); |
| 242 | return (NEG_USR32(sign ^ cache, n) ^ sign) - sign; |
| 243 | } |
| 244 | |
| 245 | static inline int get_sbits(GetBitContext *s, int n) |
| 246 | { |
| 247 | register int tmp; |
| 248 | OPEN_READER(re, s); |
| 249 | av_assert2(n>0 && n<=25); |
| 250 | UPDATE_CACHE(re, s); |
| 251 | tmp = SHOW_SBITS(re, s, n); |
| 252 | LAST_SKIP_BITS(re, s, n); |
| 253 | CLOSE_READER(re, s); |
| 254 | return tmp; |
| 255 | } |
| 256 | |
| 257 | /** |
| 258 | * Read 1-25 bits. |
| 259 | */ |
| 260 | static inline unsigned int get_bits(GetBitContext *s, int n) |
| 261 | { |
| 262 | register int tmp; |
| 263 | OPEN_READER(re, s); |
| 264 | av_assert2(n>0 && n<=25); |
| 265 | UPDATE_CACHE(re, s); |
| 266 | tmp = SHOW_UBITS(re, s, n); |
| 267 | LAST_SKIP_BITS(re, s, n); |
| 268 | CLOSE_READER(re, s); |
| 269 | return tmp; |
| 270 | } |
| 271 | |
| 272 | static inline unsigned int get_bits_le(GetBitContext *s, int n) |
| 273 | { |
| 274 | register int tmp; |
| 275 | OPEN_READER(re, s); |
| 276 | av_assert2(n>0 && n<=25); |
| 277 | UPDATE_CACHE_LE(re, s); |
| 278 | tmp = SHOW_UBITS_LE(re, s, n); |
| 279 | LAST_SKIP_BITS(re, s, n); |
| 280 | CLOSE_READER(re, s); |
| 281 | return tmp; |
| 282 | } |
| 283 | |
| 284 | /** |
| 285 | * Show 1-25 bits. |
| 286 | */ |
| 287 | static inline unsigned int show_bits(GetBitContext *s, int n) |
| 288 | { |
| 289 | register int tmp; |
| 290 | OPEN_READER_NOSIZE(re, s); |
| 291 | av_assert2(n>0 && n<=25); |
| 292 | UPDATE_CACHE(re, s); |
| 293 | tmp = SHOW_UBITS(re, s, n); |
| 294 | return tmp; |
| 295 | } |
| 296 | |
| 297 | static inline void skip_bits(GetBitContext *s, int n) |
| 298 | { |
| 299 | OPEN_READER(re, s); |
| 300 | LAST_SKIP_BITS(re, s, n); |
| 301 | CLOSE_READER(re, s); |
| 302 | } |
| 303 | |
| 304 | static inline unsigned int get_bits1(GetBitContext *s) |
| 305 | { |
| 306 | unsigned int index = s->index; |
| 307 | uint8_t result = s->buffer[index >> 3]; |
| 308 | #ifdef BITSTREAM_READER_LE |
| 309 | result >>= index & 7; |
| 310 | result &= 1; |
| 311 | #else |
| 312 | result <<= index & 7; |
| 313 | result >>= 8 - 1; |
| 314 | #endif |
| 315 | #if !UNCHECKED_BITSTREAM_READER |
| 316 | if (s->index < s->size_in_bits_plus8) |
| 317 | #endif |
| 318 | index++; |
| 319 | s->index = index; |
| 320 | |
| 321 | return result; |
| 322 | } |
| 323 | |
| 324 | static inline unsigned int show_bits1(GetBitContext *s) |
| 325 | { |
| 326 | return show_bits(s, 1); |
| 327 | } |
| 328 | |
| 329 | static inline void skip_bits1(GetBitContext *s) |
| 330 | { |
| 331 | skip_bits(s, 1); |
| 332 | } |
| 333 | |
| 334 | /** |
| 335 | * Read 0-32 bits. |
| 336 | */ |
| 337 | static inline unsigned int get_bits_long(GetBitContext *s, int n) |
| 338 | { |
| 339 | if (!n) { |
| 340 | return 0; |
| 341 | } else if (n <= MIN_CACHE_BITS) { |
| 342 | return get_bits(s, n); |
| 343 | } else { |
| 344 | #ifdef BITSTREAM_READER_LE |
| 345 | unsigned ret = get_bits(s, 16); |
| 346 | return ret | (get_bits(s, n - 16) << 16); |
| 347 | #else |
| 348 | unsigned ret = get_bits(s, 16) << (n - 16); |
| 349 | return ret | get_bits(s, n - 16); |
| 350 | #endif |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | /** |
| 355 | * Read 0-64 bits. |
| 356 | */ |
| 357 | static inline uint64_t get_bits64(GetBitContext *s, int n) |
| 358 | { |
| 359 | if (n <= 32) { |
| 360 | return get_bits_long(s, n); |
| 361 | } else { |
| 362 | #ifdef BITSTREAM_READER_LE |
| 363 | uint64_t ret = get_bits_long(s, 32); |
| 364 | return ret | (uint64_t) get_bits_long(s, n - 32) << 32; |
| 365 | #else |
| 366 | uint64_t ret = (uint64_t) get_bits_long(s, n - 32) << 32; |
| 367 | return ret | get_bits_long(s, 32); |
| 368 | #endif |
| 369 | } |
| 370 | } |
| 371 | |
| 372 | /** |
| 373 | * Read 0-32 bits as a signed integer. |
| 374 | */ |
| 375 | static inline int get_sbits_long(GetBitContext *s, int n) |
| 376 | { |
| 377 | return sign_extend(get_bits_long(s, n), n); |
| 378 | } |
| 379 | |
| 380 | /** |
| 381 | * Show 0-32 bits. |
| 382 | */ |
| 383 | static inline unsigned int show_bits_long(GetBitContext *s, int n) |
| 384 | { |
| 385 | if (n <= MIN_CACHE_BITS) { |
| 386 | return show_bits(s, n); |
| 387 | } else { |
| 388 | GetBitContext gb = *s; |
| 389 | return get_bits_long(&gb, n); |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | static inline int check_marker(GetBitContext *s, const char *msg) |
| 394 | { |
| 395 | int bit = get_bits1(s); |
| 396 | if (!bit) |
| 397 | av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg); |
| 398 | |
| 399 | return bit; |
| 400 | } |
| 401 | |
| 402 | /** |
| 403 | * Initialize GetBitContext. |
| 404 | * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes |
| 405 | * larger than the actual read bits because some optimized bitstream |
| 406 | * readers read 32 or 64 bit at once and could read over the end |
| 407 | * @param bit_size the size of the buffer in bits |
| 408 | * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. |
| 409 | */ |
| 410 | static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer, |
| 411 | int bit_size) |
| 412 | { |
| 413 | int buffer_size; |
| 414 | int ret = 0; |
| 415 | |
| 416 | if (bit_size >= INT_MAX - 7 || bit_size < 0 || !buffer) { |
| 417 | bit_size = 0; |
| 418 | buffer = NULL; |
| 419 | ret = AVERROR_INVALIDDATA; |
| 420 | } |
| 421 | |
| 422 | buffer_size = (bit_size + 7) >> 3; |
| 423 | |
| 424 | s->buffer = buffer; |
| 425 | s->size_in_bits = bit_size; |
| 426 | s->size_in_bits_plus8 = bit_size + 8; |
| 427 | s->buffer_end = buffer + buffer_size; |
| 428 | s->index = 0; |
| 429 | |
| 430 | return ret; |
| 431 | } |
| 432 | |
| 433 | /** |
| 434 | * Initialize GetBitContext. |
| 435 | * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes |
| 436 | * larger than the actual read bits because some optimized bitstream |
| 437 | * readers read 32 or 64 bit at once and could read over the end |
| 438 | * @param byte_size the size of the buffer in bytes |
| 439 | * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. |
| 440 | */ |
| 441 | static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer, |
| 442 | int byte_size) |
| 443 | { |
| 444 | if (byte_size > INT_MAX / 8 || byte_size < 0) |
| 445 | byte_size = -1; |
| 446 | return init_get_bits(s, buffer, byte_size * 8); |
| 447 | } |
| 448 | |
| 449 | static inline const uint8_t *align_get_bits(GetBitContext *s) |
| 450 | { |
| 451 | int n = -get_bits_count(s) & 7; |
| 452 | if (n) |
| 453 | skip_bits(s, n); |
| 454 | return s->buffer + (s->index >> 3); |
| 455 | } |
| 456 | |
| 457 | #define init_vlc(vlc, nb_bits, nb_codes, \ |
| 458 | bits, bits_wrap, bits_size, \ |
| 459 | codes, codes_wrap, codes_size, \ |
| 460 | flags) \ |
| 461 | ff_init_vlc_sparse(vlc, nb_bits, nb_codes, \ |
| 462 | bits, bits_wrap, bits_size, \ |
| 463 | codes, codes_wrap, codes_size, \ |
| 464 | NULL, 0, 0, flags) |
| 465 | |
| 466 | int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, |
| 467 | const void *bits, int bits_wrap, int bits_size, |
| 468 | const void *codes, int codes_wrap, int codes_size, |
| 469 | const void *symbols, int symbols_wrap, int symbols_size, |
| 470 | int flags); |
| 471 | void ff_free_vlc(VLC *vlc); |
| 472 | |
| 473 | #define INIT_VLC_LE 2 |
| 474 | #define INIT_VLC_USE_NEW_STATIC 4 |
| 475 | |
| 476 | #define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size) \ |
| 477 | do { \ |
| 478 | static VLC_TYPE table[static_size][2]; \ |
| 479 | (vlc)->table = table; \ |
| 480 | (vlc)->table_allocated = static_size; \ |
| 481 | init_vlc(vlc, bits, a, b, c, d, e, f, g, INIT_VLC_USE_NEW_STATIC); \ |
| 482 | } while (0) |
| 483 | |
| 484 | /** |
| 485 | * If the vlc code is invalid and max_depth=1, then no bits will be removed. |
| 486 | * If the vlc code is invalid and max_depth>1, then the number of bits removed |
| 487 | * is undefined. |
| 488 | */ |
| 489 | #define GET_VLC(code, name, gb, table, bits, max_depth) \ |
| 490 | do { \ |
| 491 | int n, nb_bits; \ |
| 492 | unsigned int index; \ |
| 493 | \ |
| 494 | index = SHOW_UBITS(name, gb, bits); \ |
| 495 | code = table[index][0]; \ |
| 496 | n = table[index][1]; \ |
| 497 | \ |
| 498 | if (max_depth > 1 && n < 0) { \ |
| 499 | LAST_SKIP_BITS(name, gb, bits); \ |
| 500 | UPDATE_CACHE(name, gb); \ |
| 501 | \ |
| 502 | nb_bits = -n; \ |
| 503 | \ |
| 504 | index = SHOW_UBITS(name, gb, nb_bits) + code; \ |
| 505 | code = table[index][0]; \ |
| 506 | n = table[index][1]; \ |
| 507 | if (max_depth > 2 && n < 0) { \ |
| 508 | LAST_SKIP_BITS(name, gb, nb_bits); \ |
| 509 | UPDATE_CACHE(name, gb); \ |
| 510 | \ |
| 511 | nb_bits = -n; \ |
| 512 | \ |
| 513 | index = SHOW_UBITS(name, gb, nb_bits) + code; \ |
| 514 | code = table[index][0]; \ |
| 515 | n = table[index][1]; \ |
| 516 | } \ |
| 517 | } \ |
| 518 | SKIP_BITS(name, gb, n); \ |
| 519 | } while (0) |
| 520 | |
| 521 | #define GET_RL_VLC_INTERNAL(level, run, name, gb, table, bits, \ |
| 522 | max_depth, need_update) \ |
| 523 | do { \ |
| 524 | int n, nb_bits; \ |
| 525 | unsigned int index; \ |
| 526 | \ |
| 527 | index = SHOW_UBITS(name, gb, bits); \ |
| 528 | level = table[index].level; \ |
| 529 | n = table[index].len; \ |
| 530 | \ |
| 531 | if (max_depth > 1 && n < 0) { \ |
| 532 | SKIP_BITS(name, gb, bits); \ |
| 533 | if (need_update) { \ |
| 534 | UPDATE_CACHE(name, gb); \ |
| 535 | } \ |
| 536 | \ |
| 537 | nb_bits = -n; \ |
| 538 | \ |
| 539 | index = SHOW_UBITS(name, gb, nb_bits) + level; \ |
| 540 | level = table[index].level; \ |
| 541 | n = table[index].len; \ |
| 542 | } \ |
| 543 | run = table[index].run; \ |
| 544 | SKIP_BITS(name, gb, n); \ |
| 545 | } while (0) |
| 546 | |
| 547 | /** |
| 548 | * Parse a vlc code. |
| 549 | * @param bits is the number of bits which will be read at once, must be |
| 550 | * identical to nb_bits in init_vlc() |
| 551 | * @param max_depth is the number of times bits bits must be read to completely |
| 552 | * read the longest vlc code |
| 553 | * = (max_vlc_length + bits - 1) / bits |
| 554 | */ |
| 555 | static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2], |
| 556 | int bits, int max_depth) |
| 557 | { |
| 558 | int code; |
| 559 | |
| 560 | OPEN_READER(re, s); |
| 561 | UPDATE_CACHE(re, s); |
| 562 | |
| 563 | GET_VLC(code, re, s, table, bits, max_depth); |
| 564 | |
| 565 | CLOSE_READER(re, s); |
| 566 | |
| 567 | return code; |
| 568 | } |
| 569 | |
| 570 | static inline int decode012(GetBitContext *gb) |
| 571 | { |
| 572 | int n; |
| 573 | n = get_bits1(gb); |
| 574 | if (n == 0) |
| 575 | return 0; |
| 576 | else |
| 577 | return get_bits1(gb) + 1; |
| 578 | } |
| 579 | |
| 580 | static inline int decode210(GetBitContext *gb) |
| 581 | { |
| 582 | if (get_bits1(gb)) |
| 583 | return 0; |
| 584 | else |
| 585 | return 2 - get_bits1(gb); |
| 586 | } |
| 587 | |
| 588 | static inline int get_bits_left(GetBitContext *gb) |
| 589 | { |
| 590 | return gb->size_in_bits - get_bits_count(gb); |
| 591 | } |
| 592 | |
| 593 | static inline int skip_1stop_8data_bits(GetBitContext *gb) |
| 594 | { |
| 595 | if (get_bits_left(gb) <= 0) |
| 596 | return AVERROR_INVALIDDATA; |
| 597 | |
| 598 | while (get_bits1(gb)) { |
| 599 | skip_bits(gb, 8); |
| 600 | if (get_bits_left(gb) <= 0) |
| 601 | return AVERROR_INVALIDDATA; |
| 602 | } |
| 603 | |
| 604 | return 0; |
| 605 | } |
| 606 | |
| 607 | //#define TRACE |
| 608 | |
| 609 | #ifdef TRACE |
| 610 | static inline void print_bin(int bits, int n) |
| 611 | { |
| 612 | int i; |
| 613 | |
| 614 | for (i = n - 1; i >= 0; i--) |
| 615 | av_log(NULL, AV_LOG_DEBUG, "%d", (bits >> i) & 1); |
| 616 | for (i = n; i < 24; i++) |
| 617 | av_log(NULL, AV_LOG_DEBUG, " "); |
| 618 | } |
| 619 | |
| 620 | static inline int get_bits_trace(GetBitContext *s, int n, const char *file, |
| 621 | const char *func, int line) |
| 622 | { |
| 623 | int r = get_bits(s, n); |
| 624 | |
| 625 | print_bin(r, n); |
| 626 | av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d bit @%5d in %s %s:%d\n", |
| 627 | r, n, r, get_bits_count(s) - n, file, func, line); |
| 628 | |
| 629 | return r; |
| 630 | } |
| 631 | |
| 632 | static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], |
| 633 | int bits, int max_depth, const char *file, |
| 634 | const char *func, int line) |
| 635 | { |
| 636 | int show = show_bits(s, 24); |
| 637 | int pos = get_bits_count(s); |
| 638 | int r = get_vlc2(s, table, bits, max_depth); |
| 639 | int len = get_bits_count(s) - pos; |
| 640 | int bits2 = show >> (24 - len); |
| 641 | |
| 642 | print_bin(bits2, len); |
| 643 | |
| 644 | av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", |
| 645 | bits2, len, r, pos, file, func, line); |
| 646 | |
| 647 | return r; |
| 648 | } |
| 649 | |
| 650 | #define GET_RL_VLC(level, run, name, gb, table, bits, \ |
| 651 | max_depth, need_update) \ |
| 652 | do { \ |
| 653 | int show = SHOW_UBITS(name, gb, 24); \ |
| 654 | int len; \ |
| 655 | int pos = name ## _index; \ |
| 656 | \ |
| 657 | GET_RL_VLC_INTERNAL(level, run, name, gb, table, bits,max_depth, need_update); \ |
| 658 | \ |
| 659 | len = name ## _index - pos + 1; \ |
| 660 | show = show >> (24 - len); \ |
| 661 | \ |
| 662 | print_bin(show, len); \ |
| 663 | \ |
| 664 | av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d/%-3d rlv @%5d in %s %s:%d\n",\ |
| 665 | show, len, run-1, level, pos, __FILE__, __PRETTY_FUNCTION__, __LINE__);\ |
| 666 | } while (0) \ |
| 667 | |
| 668 | |
| 669 | static inline int get_xbits_trace(GetBitContext *s, int n, const char *file, |
| 670 | const char *func, int line) |
| 671 | { |
| 672 | int show = show_bits(s, n); |
| 673 | int r = get_xbits(s, n); |
| 674 | |
| 675 | print_bin(show, n); |
| 676 | av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d xbt @%5d in %s %s:%d\n", |
| 677 | show, n, r, get_bits_count(s) - n, file, func, line); |
| 678 | |
| 679 | return r; |
| 680 | } |
| 681 | |
| 682 | #define get_bits(s, n) get_bits_trace(s , n, __FILE__, __PRETTY_FUNCTION__, __LINE__) |
| 683 | #define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__) |
| 684 | #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__) |
| 685 | |
| 686 | #define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__) |
| 687 | #define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__) |
| 688 | |
| 689 | #define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__) |
| 690 | |
| 691 | #else //TRACE |
| 692 | #define tprintf(p, ...) { } |
| 693 | #define GET_RL_VLC GET_RL_VLC_INTERNAL |
| 694 | #endif |
| 695 | |
| 696 | #endif /* AVCODEC_GET_BITS_H */ |