| Line | Branch | Exec | Source |
|---|---|---|---|
| 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/avassert.h" | ||
| 34 | |||
| 35 | #include "defs.h" | ||
| 36 | #include "mathops.h" | ||
| 37 | #include "vlc.h" | ||
| 38 | |||
| 39 | /* | ||
| 40 | * Safe bitstream reading: | ||
| 41 | * optionally, the get_bits API can check to ensure that we | ||
| 42 | * don't read past input buffer boundaries. This is protected | ||
| 43 | * with CONFIG_SAFE_BITSTREAM_READER at the global level, and | ||
| 44 | * then below that with UNCHECKED_BITSTREAM_READER at the per- | ||
| 45 | * decoder level. This means that decoders that check internally | ||
| 46 | * can "#define UNCHECKED_BITSTREAM_READER 1" to disable | ||
| 47 | * overread checks. | ||
| 48 | * Boundary checking causes a minor performance penalty so for | ||
| 49 | * applications that won't want/need this, it can be disabled | ||
| 50 | * globally using "#define CONFIG_SAFE_BITSTREAM_READER 0". | ||
| 51 | */ | ||
| 52 | #ifndef UNCHECKED_BITSTREAM_READER | ||
| 53 | #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER | ||
| 54 | #endif | ||
| 55 | |||
| 56 | #ifndef CACHED_BITSTREAM_READER | ||
| 57 | #define CACHED_BITSTREAM_READER 0 | ||
| 58 | #endif | ||
| 59 | |||
| 60 | #if CACHED_BITSTREAM_READER | ||
| 61 | |||
| 62 | // we always want the LE implementation, to provide get_bits_le() | ||
| 63 | #define BITSTREAM_LE | ||
| 64 | |||
| 65 | #ifndef BITSTREAM_READER_LE | ||
| 66 | # define BITSTREAM_BE | ||
| 67 | # define BITSTREAM_DEFAULT_BE | ||
| 68 | #endif | ||
| 69 | |||
| 70 | #include "bitstream.h" | ||
| 71 | |||
| 72 | #undef BITSTREAM_LE | ||
| 73 | #undef BITSTREAM_BE | ||
| 74 | #undef BITSTREAM_DEFAULT_BE | ||
| 75 | |||
| 76 | typedef BitstreamContext GetBitContext; | ||
| 77 | |||
| 78 | #define get_bits_count bits_tell | ||
| 79 | #define get_bits_left bits_left | ||
| 80 | #define skip_bits_long bits_skip | ||
| 81 | #define skip_bits bits_skip | ||
| 82 | #define get_bits bits_read_nz | ||
| 83 | #define get_bitsz bits_read | ||
| 84 | #define get_bits_long bits_read | ||
| 85 | #define get_bits1 bits_read_bit | ||
| 86 | #define get_bits64 bits_read_64 | ||
| 87 | #define get_xbits bits_read_xbits | ||
| 88 | #define get_sbits bits_read_signed_nz | ||
| 89 | #define get_sbits_long bits_read_signed | ||
| 90 | #define show_bits bits_peek | ||
| 91 | #define show_bits_long bits_peek | ||
| 92 | #define init_get_bits bits_init | ||
| 93 | #define init_get_bits8 bits_init8 | ||
| 94 | #define align_get_bits bits_align | ||
| 95 | #define get_vlc2 bits_read_vlc | ||
| 96 | |||
| 97 | #define init_get_bits8_le(s, buffer, byte_size) bits_init8_le((BitstreamContextLE*)s, buffer, byte_size) | ||
| 98 | #define get_bits_le(s, n) bits_read_le((BitstreamContextLE*)s, n) | ||
| 99 | |||
| 100 | #define show_bits1(s) bits_peek(s, 1) | ||
| 101 | #define skip_bits1(s) bits_skip(s, 1) | ||
| 102 | |||
| 103 | #define skip_1stop_8data_bits bits_skip_1stop_8data | ||
| 104 | |||
| 105 | #else // CACHED_BITSTREAM_READER | ||
| 106 | |||
| 107 | typedef struct GetBitContext { | ||
| 108 | const uint8_t *buffer, *buffer_end; | ||
| 109 | int index; | ||
| 110 | int size_in_bits; | ||
| 111 | int size_in_bits_plus8; | ||
| 112 | } GetBitContext; | ||
| 113 | |||
| 114 | static inline unsigned int get_bits(GetBitContext *s, int n); | ||
| 115 | static inline void skip_bits(GetBitContext *s, int n); | ||
| 116 | static inline unsigned int show_bits(GetBitContext *s, int n); | ||
| 117 | |||
| 118 | /* Bitstream reader API docs: | ||
| 119 | * name | ||
| 120 | * arbitrary name which is used as prefix for the internal variables | ||
| 121 | * | ||
| 122 | * gb | ||
| 123 | * getbitcontext | ||
| 124 | * | ||
| 125 | * OPEN_READER(name, gb) | ||
| 126 | * load gb into local variables | ||
| 127 | * | ||
| 128 | * CLOSE_READER(name, gb) | ||
| 129 | * store local vars in gb | ||
| 130 | * | ||
| 131 | * UPDATE_CACHE(name, gb) | ||
| 132 | * Refill the internal cache from the bitstream. | ||
| 133 | * After this call at least MIN_CACHE_BITS will be available. | ||
| 134 | * | ||
| 135 | * GET_CACHE(name, gb) | ||
| 136 | * Will output the contents of the internal cache, | ||
| 137 | * next bit is MSB of 32 or 64 bits (FIXME 64 bits). | ||
| 138 | * | ||
| 139 | * SHOW_UBITS(name, gb, num) | ||
| 140 | * Will return the next num bits. | ||
| 141 | * | ||
| 142 | * SHOW_SBITS(name, gb, num) | ||
| 143 | * Will return the next num bits and do sign extension. | ||
| 144 | * | ||
| 145 | * SKIP_BITS(name, gb, num) | ||
| 146 | * Will skip over the next num bits. | ||
| 147 | * Note, this is equivalent to SKIP_CACHE; SKIP_COUNTER. | ||
| 148 | * | ||
| 149 | * SKIP_CACHE(name, gb, num) | ||
| 150 | * Will remove the next num bits from the cache (note SKIP_COUNTER | ||
| 151 | * MUST be called before UPDATE_CACHE / CLOSE_READER). | ||
| 152 | * | ||
| 153 | * SKIP_COUNTER(name, gb, num) | ||
| 154 | * Will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS). | ||
| 155 | * | ||
| 156 | * LAST_SKIP_BITS(name, gb, num) | ||
| 157 | * Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER. | ||
| 158 | * | ||
| 159 | * BITS_LEFT(name, gb) | ||
| 160 | * Return the number of bits left | ||
| 161 | * | ||
| 162 | * For examples see get_bits, show_bits, skip_bits, get_vlc. | ||
| 163 | */ | ||
| 164 | |||
| 165 | #if defined LONG_BITSTREAM_READER | ||
| 166 | # define MIN_CACHE_BITS 32 | ||
| 167 | #else | ||
| 168 | # define MIN_CACHE_BITS 25 | ||
| 169 | #endif | ||
| 170 | |||
| 171 | #define OPEN_READER_NOSIZE(name, gb) \ | ||
| 172 | unsigned int name ## _index = (gb)->index; \ | ||
| 173 | unsigned int av_unused name ## _cache | ||
| 174 | |||
| 175 | #if UNCHECKED_BITSTREAM_READER | ||
| 176 | #define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb) | ||
| 177 | |||
| 178 | #define BITS_AVAILABLE(name, gb) 1 | ||
| 179 | #else | ||
| 180 | #define OPEN_READER(name, gb) \ | ||
| 181 | OPEN_READER_NOSIZE(name, gb); \ | ||
| 182 | unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8 | ||
| 183 | |||
| 184 | #define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8 | ||
| 185 | #endif | ||
| 186 | |||
| 187 | #define CLOSE_READER(name, gb) (gb)->index = name ## _index | ||
| 188 | |||
| 189 | # ifdef LONG_BITSTREAM_READER | ||
| 190 | |||
| 191 | # define UPDATE_CACHE_LE(name, gb) name ## _cache = \ | ||
| 192 | AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7) | ||
| 193 | |||
| 194 | # define UPDATE_CACHE_BE(name, gb) name ## _cache = \ | ||
| 195 | AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7)) | ||
| 196 | |||
| 197 | #else | ||
| 198 | |||
| 199 | # define UPDATE_CACHE_LE(name, gb) name ## _cache = \ | ||
| 200 | AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7) | ||
| 201 | |||
| 202 | # define UPDATE_CACHE_BE(name, gb) name ## _cache = \ | ||
| 203 | AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7) | ||
| 204 | |||
| 205 | #endif | ||
| 206 | |||
| 207 | |||
| 208 | #ifdef BITSTREAM_READER_LE | ||
| 209 | |||
| 210 | # define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb) | ||
| 211 | |||
| 212 | # define SKIP_CACHE(name, gb, num) name ## _cache >>= (num) | ||
| 213 | |||
| 214 | #else | ||
| 215 | |||
| 216 | # define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb) | ||
| 217 | |||
| 218 | # define SKIP_CACHE(name, gb, num) name ## _cache <<= (num) | ||
| 219 | |||
| 220 | #endif | ||
| 221 | |||
| 222 | #if UNCHECKED_BITSTREAM_READER | ||
| 223 | # define SKIP_COUNTER(name, gb, num) name ## _index += (num) | ||
| 224 | #else | ||
| 225 | # define SKIP_COUNTER(name, gb, num) \ | ||
| 226 | name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num)) | ||
| 227 | #endif | ||
| 228 | |||
| 229 | #define BITS_LEFT(name, gb) ((int)((gb)->size_in_bits - name ## _index)) | ||
| 230 | |||
| 231 | #define SKIP_BITS(name, gb, num) \ | ||
| 232 | do { \ | ||
| 233 | SKIP_CACHE(name, gb, num); \ | ||
| 234 | SKIP_COUNTER(name, gb, num); \ | ||
| 235 | } while (0) | ||
| 236 | |||
| 237 | #define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num) | ||
| 238 | |||
| 239 | #define SHOW_UBITS_LE(name, gb, num) zero_extend(name ## _cache, num) | ||
| 240 | #define SHOW_SBITS_LE(name, gb, num) sign_extend(name ## _cache, num) | ||
| 241 | |||
| 242 | #define SHOW_UBITS_BE(name, gb, num) NEG_USR32(name ## _cache, num) | ||
| 243 | #define SHOW_SBITS_BE(name, gb, num) NEG_SSR32(name ## _cache, num) | ||
| 244 | |||
| 245 | #ifdef BITSTREAM_READER_LE | ||
| 246 | # define SHOW_UBITS(name, gb, num) SHOW_UBITS_LE(name, gb, num) | ||
| 247 | # define SHOW_SBITS(name, gb, num) SHOW_SBITS_LE(name, gb, num) | ||
| 248 | #else | ||
| 249 | # define SHOW_UBITS(name, gb, num) SHOW_UBITS_BE(name, gb, num) | ||
| 250 | # define SHOW_SBITS(name, gb, num) SHOW_SBITS_BE(name, gb, num) | ||
| 251 | #endif | ||
| 252 | |||
| 253 | #define GET_CACHE(name, gb) ((uint32_t) name ## _cache) | ||
| 254 | |||
| 255 | |||
| 256 | 309021189 | static inline int get_bits_count(const GetBitContext *s) | |
| 257 | { | ||
| 258 | 309021189 | return s->index; | |
| 259 | } | ||
| 260 | |||
| 261 | /** | ||
| 262 | * Skips the specified number of bits. | ||
| 263 | * @param n the number of bits to skip, | ||
| 264 | * For the UNCHECKED_BITSTREAM_READER this must not cause the distance | ||
| 265 | * from the start to overflow int32_t. Staying within the bitstream + padding | ||
| 266 | * is sufficient, too. | ||
| 267 | */ | ||
| 268 | 3390151 | static inline void skip_bits_long(GetBitContext *s, int n) | |
| 269 | { | ||
| 270 | #if UNCHECKED_BITSTREAM_READER | ||
| 271 | 2755860 | s->index += n; | |
| 272 | #else | ||
| 273 | 634291 | s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index); | |
| 274 | #endif | ||
| 275 | 3390151 | } | |
| 276 | |||
| 277 | /** | ||
| 278 | * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB). | ||
| 279 | * if MSB not set it is negative | ||
| 280 | * @param n length in bits | ||
| 281 | */ | ||
| 282 | 26836244 | static inline int get_xbits(GetBitContext *s, int n) | |
| 283 | { | ||
| 284 | register int sign; | ||
| 285 | register int32_t cache; | ||
| 286 | 26836244 | OPEN_READER(re, s); | |
| 287 | av_assert2(n>0 && n<=25); | ||
| 288 | 26836244 | UPDATE_CACHE(re, s); | |
| 289 | 26836244 | cache = GET_CACHE(re, s); | |
| 290 | 26836244 | sign = ~cache >> 31; | |
| 291 | 26836244 | LAST_SKIP_BITS(re, s, n); | |
| 292 | 26836244 | CLOSE_READER(re, s); | |
| 293 | 26836244 | return (NEG_USR32(sign ^ cache, n) ^ sign) - sign; | |
| 294 | } | ||
| 295 | |||
| 296 | 1534760 | static inline int get_xbits_le(GetBitContext *s, int n) | |
| 297 | { | ||
| 298 | register int sign; | ||
| 299 | register int32_t cache; | ||
| 300 | 1534760 | OPEN_READER(re, s); | |
| 301 | av_assert2(n>0 && n<=25); | ||
| 302 | 1534760 | UPDATE_CACHE_LE(re, s); | |
| 303 | 1534760 | cache = GET_CACHE(re, s); | |
| 304 | 1534760 | sign = sign_extend(~cache, n) >> 31; | |
| 305 | 1534760 | LAST_SKIP_BITS(re, s, n); | |
| 306 | 1534760 | CLOSE_READER(re, s); | |
| 307 | 1534760 | return (zero_extend(sign ^ cache, n) ^ sign) - sign; | |
| 308 | } | ||
| 309 | |||
| 310 | 33301656 | static inline int get_sbits(GetBitContext *s, int n) | |
| 311 | { | ||
| 312 | register int tmp; | ||
| 313 | 33301656 | OPEN_READER(re, s); | |
| 314 | av_assert2(n>0 && n<=25); | ||
| 315 | 33301656 | UPDATE_CACHE(re, s); | |
| 316 | 33301656 | tmp = SHOW_SBITS(re, s, n); | |
| 317 | 33301656 | LAST_SKIP_BITS(re, s, n); | |
| 318 | 33301656 | CLOSE_READER(re, s); | |
| 319 | 33301656 | return tmp; | |
| 320 | } | ||
| 321 | |||
| 322 | /** | ||
| 323 | * Read 1-25 bits. | ||
| 324 | */ | ||
| 325 | 323780091 | static inline unsigned int get_bits(GetBitContext *s, int n) | |
| 326 | { | ||
| 327 | register unsigned int tmp; | ||
| 328 | 323780091 | OPEN_READER(re, s); | |
| 329 | av_assert2(n>0 && n<=25); | ||
| 330 | 323780091 | UPDATE_CACHE(re, s); | |
| 331 | 323780091 | tmp = SHOW_UBITS(re, s, n); | |
| 332 | 323780091 | LAST_SKIP_BITS(re, s, n); | |
| 333 | 323780091 | CLOSE_READER(re, s); | |
| 334 | av_assert2(tmp < UINT64_C(1) << n); | ||
| 335 | 323780091 | return tmp; | |
| 336 | } | ||
| 337 | |||
| 338 | /** | ||
| 339 | * Read 0-25 bits. | ||
| 340 | */ | ||
| 341 | 762341 | static av_always_inline int get_bitsz(GetBitContext *s, int n) | |
| 342 | { | ||
| 343 |
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762341 | return n ? get_bits(s, n) : 0; |
| 344 | } | ||
| 345 | |||
| 346 | 718813 | static inline unsigned int get_bits_le(GetBitContext *s, int n) | |
| 347 | { | ||
| 348 | register int tmp; | ||
| 349 | 718813 | OPEN_READER(re, s); | |
| 350 | av_assert2(n>0 && n<=25); | ||
| 351 | 718813 | UPDATE_CACHE_LE(re, s); | |
| 352 | 718813 | tmp = SHOW_UBITS_LE(re, s, n); | |
| 353 | 718813 | LAST_SKIP_BITS(re, s, n); | |
| 354 | 718813 | CLOSE_READER(re, s); | |
| 355 | 718813 | return tmp; | |
| 356 | } | ||
| 357 | |||
| 358 | /** | ||
| 359 | * Show 1-25 bits. | ||
| 360 | */ | ||
| 361 | 114200007 | static inline unsigned int show_bits(GetBitContext *s, int n) | |
| 362 | { | ||
| 363 | register unsigned int tmp; | ||
| 364 | 114200007 | OPEN_READER_NOSIZE(re, s); | |
| 365 | av_assert2(n>0 && n<=25); | ||
| 366 | 114200007 | UPDATE_CACHE(re, s); | |
| 367 | 114200007 | tmp = SHOW_UBITS(re, s, n); | |
| 368 | 114200007 | return tmp; | |
| 369 | } | ||
| 370 | |||
| 371 | 111390826 | static inline void skip_bits(GetBitContext *s, int n) | |
| 372 | { | ||
| 373 | 111390826 | OPEN_READER(re, s); | |
| 374 | 111390826 | LAST_SKIP_BITS(re, s, n); | |
| 375 | 111390826 | CLOSE_READER(re, s); | |
| 376 | 111390826 | } | |
| 377 | |||
| 378 | 446929580 | static inline unsigned int get_bits1(GetBitContext *s) | |
| 379 | { | ||
| 380 | 446929580 | unsigned int index = s->index; | |
| 381 | 446929580 | uint8_t result = s->buffer[index >> 3]; | |
| 382 | #ifdef BITSTREAM_READER_LE | ||
| 383 | 261126126 | result >>= index & 7; | |
| 384 | 261126126 | result &= 1; | |
| 385 | #else | ||
| 386 | 185803454 | result <<= index & 7; | |
| 387 | 185803454 | result >>= 8 - 1; | |
| 388 | #endif | ||
| 389 | #if !UNCHECKED_BITSTREAM_READER | ||
| 390 |
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404275062 | if (s->index < s->size_in_bits_plus8) |
| 391 | #endif | ||
| 392 | 446914203 | index++; | |
| 393 | 446929580 | s->index = index; | |
| 394 | |||
| 395 | 446929580 | return result; | |
| 396 | } | ||
| 397 | |||
| 398 | 43150 | static inline unsigned int show_bits1(GetBitContext *s) | |
| 399 | { | ||
| 400 | 43150 | return show_bits(s, 1); | |
| 401 | } | ||
| 402 | |||
| 403 | 282734 | static inline void skip_bits1(GetBitContext *s) | |
| 404 | { | ||
| 405 | 282734 | skip_bits(s, 1); | |
| 406 | 282734 | } | |
| 407 | |||
| 408 | /** | ||
| 409 | * Read 0-32 bits. | ||
| 410 | */ | ||
| 411 | 54943175 | static inline unsigned int get_bits_long(GetBitContext *s, int n) | |
| 412 | { | ||
| 413 | av_assert2(n>=0 && n<=32); | ||
| 414 |
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54943175 | if (!n) { |
| 415 | 3404960 | return 0; | |
| 416 |
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51538215 | } else if (n <= MIN_CACHE_BITS) { |
| 417 | 48140627 | return get_bits(s, n); | |
| 418 | } else { | ||
| 419 | #ifdef BITSTREAM_READER_LE | ||
| 420 | 2417 | unsigned ret = get_bits(s, 16); | |
| 421 | 2417 | return ret | (get_bits(s, n - 16) << 16); | |
| 422 | #else | ||
| 423 | 3395171 | unsigned ret = get_bits(s, 16) << (n - 16); | |
| 424 | 3395171 | return ret | get_bits(s, n - 16); | |
| 425 | #endif | ||
| 426 | } | ||
| 427 | } | ||
| 428 | |||
| 429 | /** | ||
| 430 | * Read 0-64 bits. | ||
| 431 | */ | ||
| 432 | 11094 | static inline uint64_t get_bits64(GetBitContext *s, int n) | |
| 433 | { | ||
| 434 |
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11094 | if (n <= 32) { |
| 435 | 6375 | return get_bits_long(s, n); | |
| 436 | } else { | ||
| 437 | #ifdef BITSTREAM_READER_LE | ||
| 438 | 1 | uint64_t ret = get_bits_long(s, 32); | |
| 439 | 1 | return ret | (uint64_t) get_bits_long(s, n - 32) << 32; | |
| 440 | #else | ||
| 441 | 4718 | uint64_t ret = (uint64_t) get_bits_long(s, n - 32) << 32; | |
| 442 | 4718 | return ret | get_bits_long(s, 32); | |
| 443 | #endif | ||
| 444 | } | ||
| 445 | } | ||
| 446 | |||
| 447 | /** | ||
| 448 | * Read 0-32 bits as a signed integer. | ||
| 449 | */ | ||
| 450 | 4766298 | static inline int get_sbits_long(GetBitContext *s, int n) | |
| 451 | { | ||
| 452 | // sign_extend(x, 0) is undefined | ||
| 453 |
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4766298 | if (!n) |
| 454 | ✗ | return 0; | |
| 455 | |||
| 456 | 4766298 | return sign_extend(get_bits_long(s, n), n); | |
| 457 | } | ||
| 458 | |||
| 459 | /** | ||
| 460 | * Read 0-64 bits as a signed integer. | ||
| 461 | */ | ||
| 462 | 4624 | static inline int64_t get_sbits64(GetBitContext *s, int n) | |
| 463 | { | ||
| 464 | // sign_extend(x, 0) is undefined | ||
| 465 |
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4624 | if (!n) |
| 466 | ✗ | return 0; | |
| 467 | |||
| 468 | 4624 | return sign_extend64(get_bits64(s, n), n); | |
| 469 | } | ||
| 470 | |||
| 471 | /** | ||
| 472 | * Show 0-32 bits. | ||
| 473 | */ | ||
| 474 | 3153015 | static inline unsigned int show_bits_long(GetBitContext *s, int n) | |
| 475 | { | ||
| 476 |
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3153015 | if (n <= MIN_CACHE_BITS) { |
| 477 | 6799 | return show_bits(s, n); | |
| 478 | } else { | ||
| 479 | 3146216 | GetBitContext gb = *s; | |
| 480 | 3146216 | return get_bits_long(&gb, n); | |
| 481 | } | ||
| 482 | } | ||
| 483 | |||
| 484 | |||
| 485 | /** | ||
| 486 | * Initialize GetBitContext. | ||
| 487 | * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes | ||
| 488 | * larger than the actual read bits because some optimized bitstream | ||
| 489 | * readers read 32 or 64 bit at once and could read over the end | ||
| 490 | * @param bit_size the size of the buffer in bits | ||
| 491 | * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. | ||
| 492 | */ | ||
| 493 | 28784111 | static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer, | |
| 494 | int bit_size) | ||
| 495 | { | ||
| 496 | int buffer_size; | ||
| 497 | 28784111 | int ret = 0; | |
| 498 | |||
| 499 |
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28784111 | if (bit_size >= INT_MAX - FFMAX(7, AV_INPUT_BUFFER_PADDING_SIZE*8) || bit_size < 0 || !buffer) { |
| 500 | 4 | bit_size = 0; | |
| 501 | 4 | buffer = NULL; | |
| 502 | 4 | ret = AVERROR_INVALIDDATA; | |
| 503 | } | ||
| 504 | |||
| 505 | 28784111 | buffer_size = (bit_size + 7) >> 3; | |
| 506 | |||
| 507 | 28784111 | s->buffer = buffer; | |
| 508 | 28784111 | s->size_in_bits = bit_size; | |
| 509 | 28784111 | s->size_in_bits_plus8 = bit_size + 8; | |
| 510 | 28784111 | s->buffer_end = buffer + buffer_size; | |
| 511 | 28784111 | s->index = 0; | |
| 512 | |||
| 513 | 28784111 | return ret; | |
| 514 | } | ||
| 515 | |||
| 516 | /** | ||
| 517 | * Initialize GetBitContext. | ||
| 518 | * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes | ||
| 519 | * larger than the actual read bits because some optimized bitstream | ||
| 520 | * readers read 32 or 64 bit at once and could read over the end | ||
| 521 | * @param byte_size the size of the buffer in bytes | ||
| 522 | * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. | ||
| 523 | */ | ||
| 524 | 590689 | static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer, | |
| 525 | int byte_size) | ||
| 526 | { | ||
| 527 |
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590689 | if (byte_size > INT_MAX / 8 || byte_size < 0) |
| 528 | ✗ | byte_size = -1; | |
| 529 | 590689 | return init_get_bits(s, buffer, byte_size * 8); | |
| 530 | } | ||
| 531 | |||
| 532 | 200 | static inline int init_get_bits8_le(GetBitContext *s, const uint8_t *buffer, | |
| 533 | int byte_size) | ||
| 534 | { | ||
| 535 |
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200 | if (byte_size > INT_MAX / 8 || byte_size < 0) |
| 536 | ✗ | byte_size = -1; | |
| 537 | 200 | return init_get_bits(s, buffer, byte_size * 8); | |
| 538 | } | ||
| 539 | |||
| 540 | 277905 | static inline const uint8_t *align_get_bits(GetBitContext *s) | |
| 541 | { | ||
| 542 | 277905 | int n = -get_bits_count(s) & 7; | |
| 543 |
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277905 | if (n) |
| 544 | 92549 | skip_bits(s, n); | |
| 545 | 277905 | return s->buffer + (s->index >> 3); | |
| 546 | } | ||
| 547 | |||
| 548 | /** | ||
| 549 | * If the vlc code is invalid and max_depth=1, then no bits will be removed. | ||
| 550 | * If the vlc code is invalid and max_depth>1, then the number of bits removed | ||
| 551 | * is undefined. | ||
| 552 | */ | ||
| 553 | #define GET_VLC(code, name, gb, table, bits, max_depth) \ | ||
| 554 | do { \ | ||
| 555 | int n, nb_bits; \ | ||
| 556 | unsigned int index; \ | ||
| 557 | \ | ||
| 558 | index = SHOW_UBITS(name, gb, bits); \ | ||
| 559 | code = table[index].sym; \ | ||
| 560 | n = table[index].len; \ | ||
| 561 | \ | ||
| 562 | if (max_depth > 1 && n < 0) { \ | ||
| 563 | LAST_SKIP_BITS(name, gb, bits); \ | ||
| 564 | UPDATE_CACHE(name, gb); \ | ||
| 565 | \ | ||
| 566 | nb_bits = -n; \ | ||
| 567 | \ | ||
| 568 | index = SHOW_UBITS(name, gb, nb_bits) + code; \ | ||
| 569 | code = table[index].sym; \ | ||
| 570 | n = table[index].len; \ | ||
| 571 | if (max_depth > 2 && n < 0) { \ | ||
| 572 | LAST_SKIP_BITS(name, gb, nb_bits); \ | ||
| 573 | UPDATE_CACHE(name, gb); \ | ||
| 574 | \ | ||
| 575 | nb_bits = -n; \ | ||
| 576 | \ | ||
| 577 | index = SHOW_UBITS(name, gb, nb_bits) + code; \ | ||
| 578 | code = table[index].sym; \ | ||
| 579 | n = table[index].len; \ | ||
| 580 | } \ | ||
| 581 | } \ | ||
| 582 | SKIP_BITS(name, gb, n); \ | ||
| 583 | } while (0) | ||
| 584 | |||
| 585 | #define GET_RL_VLC(level, run, name, gb, table, bits, \ | ||
| 586 | max_depth, need_update) \ | ||
| 587 | do { \ | ||
| 588 | int n, nb_bits; \ | ||
| 589 | unsigned int index; \ | ||
| 590 | \ | ||
| 591 | index = SHOW_UBITS(name, gb, bits); \ | ||
| 592 | level = table[index].level; \ | ||
| 593 | n = table[index].len; \ | ||
| 594 | \ | ||
| 595 | if (max_depth > 1 && n < 0) { \ | ||
| 596 | SKIP_BITS(name, gb, bits); \ | ||
| 597 | if (need_update) { \ | ||
| 598 | UPDATE_CACHE(name, gb); \ | ||
| 599 | } \ | ||
| 600 | \ | ||
| 601 | nb_bits = -n; \ | ||
| 602 | \ | ||
| 603 | index = SHOW_UBITS(name, gb, nb_bits) + level; \ | ||
| 604 | level = table[index].level; \ | ||
| 605 | n = table[index].len; \ | ||
| 606 | if (max_depth > 2 && n < 0) { \ | ||
| 607 | LAST_SKIP_BITS(name, gb, nb_bits); \ | ||
| 608 | if (need_update) { \ | ||
| 609 | UPDATE_CACHE(name, gb); \ | ||
| 610 | } \ | ||
| 611 | nb_bits = -n; \ | ||
| 612 | \ | ||
| 613 | index = SHOW_UBITS(name, gb, nb_bits) + level; \ | ||
| 614 | level = table[index].level; \ | ||
| 615 | n = table[index].len; \ | ||
| 616 | } \ | ||
| 617 | } \ | ||
| 618 | run = table[index].run; \ | ||
| 619 | SKIP_BITS(name, gb, n); \ | ||
| 620 | } while (0) | ||
| 621 | |||
| 622 | /** | ||
| 623 | * Parse a vlc code. | ||
| 624 | * @param bits is the number of bits which will be read at once, must be | ||
| 625 | * identical to nb_bits in init_vlc() | ||
| 626 | * @param max_depth is the number of times bits bits must be read to completely | ||
| 627 | * read the longest vlc code | ||
| 628 | * = (max_vlc_length + bits - 1) / bits | ||
| 629 | * @returns the code parsed or -1 if no vlc matches | ||
| 630 | */ | ||
| 631 | 289227123 | static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table, | |
| 632 | int bits, int max_depth) | ||
| 633 | { | ||
| 634 | int code; | ||
| 635 | |||
| 636 | 289227123 | OPEN_READER(re, s); | |
| 637 | 289227123 | UPDATE_CACHE(re, s); | |
| 638 | |||
| 639 |
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289227123 | GET_VLC(code, re, s, table, bits, max_depth); |
| 640 | |||
| 641 | 289227123 | CLOSE_READER(re, s); | |
| 642 | |||
| 643 | 289227123 | return code; | |
| 644 | } | ||
| 645 | |||
| 646 | 378513 | static inline int decode012(GetBitContext *gb) | |
| 647 | { | ||
| 648 | int n; | ||
| 649 | 378513 | n = get_bits1(gb); | |
| 650 |
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378513 | if (n == 0) |
| 651 | 263658 | return 0; | |
| 652 | else | ||
| 653 | 114855 | return get_bits1(gb) + 1; | |
| 654 | } | ||
| 655 | |||
| 656 | 180374 | static inline int decode210(GetBitContext *gb) | |
| 657 | { | ||
| 658 |
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180374 | if (get_bits1(gb)) |
| 659 | 131153 | return 0; | |
| 660 | else | ||
| 661 | 49221 | return 2 - get_bits1(gb); | |
| 662 | } | ||
| 663 | |||
| 664 | 274260151 | static inline int get_bits_left(GetBitContext *gb) | |
| 665 | { | ||
| 666 | 274260151 | return gb->size_in_bits - get_bits_count(gb); | |
| 667 | } | ||
| 668 | |||
| 669 | 130058 | static inline int skip_1stop_8data_bits(GetBitContext *gb) | |
| 670 | { | ||
| 671 |
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130058 | if (get_bits_left(gb) <= 0) |
| 672 | ✗ | return AVERROR_INVALIDDATA; | |
| 673 | |||
| 674 |
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131615 | while (get_bits1(gb)) { |
| 675 | 1557 | skip_bits(gb, 8); | |
| 676 |
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1557 | if (get_bits_left(gb) <= 0) |
| 677 | ✗ | return AVERROR_INVALIDDATA; | |
| 678 | } | ||
| 679 | |||
| 680 | 130058 | return 0; | |
| 681 | } | ||
| 682 | |||
| 683 | #endif // CACHED_BITSTREAM_READER | ||
| 684 | |||
| 685 | #endif /* AVCODEC_GET_BITS_H */ | ||
| 686 |