| 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 | #define get_vlc_multi bits_read_vlc_multi | ||
| 97 | |||
| 98 | #define init_get_bits8_le(s, buffer, byte_size) bits_init8_le((BitstreamContextLE*)s, buffer, byte_size) | ||
| 99 | #define get_bits_le(s, n) bits_read_le((BitstreamContextLE*)s, n) | ||
| 100 | |||
| 101 | #define show_bits1(s) bits_peek(s, 1) | ||
| 102 | #define skip_bits1(s) bits_skip(s, 1) | ||
| 103 | |||
| 104 | #define skip_1stop_8data_bits bits_skip_1stop_8data | ||
| 105 | |||
| 106 | #else // CACHED_BITSTREAM_READER | ||
| 107 | |||
| 108 | typedef struct GetBitContext { | ||
| 109 | const uint8_t *buffer, *buffer_end; | ||
| 110 | int index; | ||
| 111 | int size_in_bits; | ||
| 112 | int size_in_bits_plus8; | ||
| 113 | } GetBitContext; | ||
| 114 | |||
| 115 | static inline unsigned int get_bits(GetBitContext *s, int n); | ||
| 116 | static inline void skip_bits(GetBitContext *s, int n); | ||
| 117 | static inline unsigned int show_bits(GetBitContext *s, int n); | ||
| 118 | |||
| 119 | /* Bitstream reader API docs: | ||
| 120 | * name | ||
| 121 | * arbitrary name which is used as prefix for the internal variables | ||
| 122 | * | ||
| 123 | * gb | ||
| 124 | * getbitcontext | ||
| 125 | * | ||
| 126 | * OPEN_READER(name, gb) | ||
| 127 | * load gb into local variables | ||
| 128 | * | ||
| 129 | * CLOSE_READER(name, gb) | ||
| 130 | * store local vars in gb | ||
| 131 | * | ||
| 132 | * UPDATE_CACHE(name, gb) | ||
| 133 | * Refill the internal cache from the bitstream. | ||
| 134 | * After this call at least MIN_CACHE_BITS will be available. | ||
| 135 | * | ||
| 136 | * GET_CACHE(name, gb) | ||
| 137 | * Will output the contents of the internal cache, | ||
| 138 | * next bit is MSB of 32 or 64 bits (FIXME 64 bits). | ||
| 139 | * | ||
| 140 | * SHOW_UBITS(name, gb, num) | ||
| 141 | * Will return the next num bits. | ||
| 142 | * | ||
| 143 | * SHOW_SBITS(name, gb, num) | ||
| 144 | * Will return the next num bits and do sign extension. | ||
| 145 | * | ||
| 146 | * SKIP_BITS(name, gb, num) | ||
| 147 | * Will skip over the next num bits. | ||
| 148 | * Note, this is equivalent to SKIP_CACHE; SKIP_COUNTER. | ||
| 149 | * | ||
| 150 | * SKIP_CACHE(name, gb, num) | ||
| 151 | * Will remove the next num bits from the cache (note SKIP_COUNTER | ||
| 152 | * MUST be called before UPDATE_CACHE / CLOSE_READER). | ||
| 153 | * | ||
| 154 | * SKIP_COUNTER(name, gb, num) | ||
| 155 | * Will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS). | ||
| 156 | * | ||
| 157 | * LAST_SKIP_BITS(name, gb, num) | ||
| 158 | * Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER. | ||
| 159 | * | ||
| 160 | * BITS_LEFT(name, gb) | ||
| 161 | * Return the number of bits left | ||
| 162 | * | ||
| 163 | * For examples see get_bits, show_bits, skip_bits, get_vlc. | ||
| 164 | */ | ||
| 165 | |||
| 166 | #if defined LONG_BITSTREAM_READER | ||
| 167 | # define MIN_CACHE_BITS 32 | ||
| 168 | #else | ||
| 169 | # define MIN_CACHE_BITS 25 | ||
| 170 | #endif | ||
| 171 | |||
| 172 | #define OPEN_READER_NOSIZE(name, gb) \ | ||
| 173 | unsigned int name ## _index = (gb)->index; \ | ||
| 174 | unsigned int av_unused name ## _cache | ||
| 175 | |||
| 176 | #if UNCHECKED_BITSTREAM_READER | ||
| 177 | #define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb) | ||
| 178 | |||
| 179 | #define BITS_AVAILABLE(name, gb) 1 | ||
| 180 | #else | ||
| 181 | #define OPEN_READER(name, gb) \ | ||
| 182 | OPEN_READER_NOSIZE(name, gb); \ | ||
| 183 | unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8 | ||
| 184 | |||
| 185 | #define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8 | ||
| 186 | #endif | ||
| 187 | |||
| 188 | #define CLOSE_READER(name, gb) (gb)->index = name ## _index | ||
| 189 | |||
| 190 | #define UPDATE_CACHE_BE_EXT(name, gb, bits, dst_bits) name ## _cache = \ | ||
| 191 | AV_RB ## bits((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7) >> (bits - dst_bits) | ||
| 192 | |||
| 193 | #define UPDATE_CACHE_LE_EXT(name, gb, bits, dst_bits) name ## _cache = \ | ||
| 194 | (uint ## dst_bits ## _t)(AV_RL ## bits((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)) | ||
| 195 | |||
| 196 | /* Using these two macros ensures that 32 bits are available. */ | ||
| 197 | # define UPDATE_CACHE_LE_32(name, gb) UPDATE_CACHE_LE_EXT(name, (gb), 64, 32) | ||
| 198 | |||
| 199 | # define UPDATE_CACHE_BE_32(name, gb) UPDATE_CACHE_BE_EXT(name, (gb), 64, 32) | ||
| 200 | |||
| 201 | # ifdef LONG_BITSTREAM_READER | ||
| 202 | |||
| 203 | # define UPDATE_CACHE_LE(name, gb) UPDATE_CACHE_LE_32(name, (gb)) | ||
| 204 | |||
| 205 | # define UPDATE_CACHE_BE(name, gb) UPDATE_CACHE_BE_32(name, (gb)) | ||
| 206 | |||
| 207 | #else | ||
| 208 | |||
| 209 | # define UPDATE_CACHE_LE(name, gb) UPDATE_CACHE_LE_EXT(name, (gb), 32, 32) | ||
| 210 | |||
| 211 | # define UPDATE_CACHE_BE(name, gb) UPDATE_CACHE_BE_EXT(name, (gb), 32, 32) | ||
| 212 | |||
| 213 | #endif | ||
| 214 | |||
| 215 | |||
| 216 | #ifdef BITSTREAM_READER_LE | ||
| 217 | |||
| 218 | # define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb) | ||
| 219 | # define UPDATE_CACHE_32(name, gb) UPDATE_CACHE_LE_32(name, (gb)) | ||
| 220 | |||
| 221 | # define SKIP_CACHE(name, gb, num) name ## _cache >>= (num) | ||
| 222 | |||
| 223 | #else | ||
| 224 | |||
| 225 | # define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb) | ||
| 226 | # define UPDATE_CACHE_32(name, gb) UPDATE_CACHE_BE_32(name, (gb)) | ||
| 227 | |||
| 228 | # define SKIP_CACHE(name, gb, num) name ## _cache <<= (num) | ||
| 229 | |||
| 230 | #endif | ||
| 231 | |||
| 232 | #if UNCHECKED_BITSTREAM_READER | ||
| 233 | # define SKIP_COUNTER(name, gb, num) name ## _index += (num) | ||
| 234 | #else | ||
| 235 | # define SKIP_COUNTER(name, gb, num) \ | ||
| 236 | name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num)) | ||
| 237 | #endif | ||
| 238 | |||
| 239 | #define BITS_LEFT(name, gb) ((int)((gb)->size_in_bits - name ## _index)) | ||
| 240 | |||
| 241 | #define SKIP_BITS(name, gb, num) \ | ||
| 242 | do { \ | ||
| 243 | SKIP_CACHE(name, gb, num); \ | ||
| 244 | SKIP_COUNTER(name, gb, num); \ | ||
| 245 | } while (0) | ||
| 246 | |||
| 247 | #define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num) | ||
| 248 | |||
| 249 | #define SHOW_UBITS_LE(name, gb, num) zero_extend(name ## _cache, num) | ||
| 250 | #define SHOW_SBITS_LE(name, gb, num) sign_extend(name ## _cache, num) | ||
| 251 | |||
| 252 | #define SHOW_UBITS_BE(name, gb, num) NEG_USR32(name ## _cache, num) | ||
| 253 | #define SHOW_SBITS_BE(name, gb, num) NEG_SSR32(name ## _cache, num) | ||
| 254 | |||
| 255 | #ifdef BITSTREAM_READER_LE | ||
| 256 | # define SHOW_UBITS(name, gb, num) SHOW_UBITS_LE(name, gb, num) | ||
| 257 | # define SHOW_SBITS(name, gb, num) SHOW_SBITS_LE(name, gb, num) | ||
| 258 | #else | ||
| 259 | # define SHOW_UBITS(name, gb, num) SHOW_UBITS_BE(name, gb, num) | ||
| 260 | # define SHOW_SBITS(name, gb, num) SHOW_SBITS_BE(name, gb, num) | ||
| 261 | #endif | ||
| 262 | |||
| 263 | #define GET_CACHE(name, gb) ((uint32_t) name ## _cache) | ||
| 264 | |||
| 265 | |||
| 266 | 305264420 | static inline int get_bits_count(const GetBitContext *s) | |
| 267 | { | ||
| 268 | 305264420 | return s->index; | |
| 269 | } | ||
| 270 | |||
| 271 | /** | ||
| 272 | * Skips the specified number of bits. | ||
| 273 | * @param n the number of bits to skip, | ||
| 274 | * For the UNCHECKED_BITSTREAM_READER this must not cause the distance | ||
| 275 | * from the start to overflow int32_t. Staying within the bitstream + padding | ||
| 276 | * is sufficient, too. | ||
| 277 | */ | ||
| 278 | 4700033 | static inline void skip_bits_long(GetBitContext *s, int n) | |
| 279 | { | ||
| 280 | #if UNCHECKED_BITSTREAM_READER | ||
| 281 | 2782742 | s->index += n; | |
| 282 | #else | ||
| 283 | 1917291 | s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index); | |
| 284 | #endif | ||
| 285 | 4700033 | } | |
| 286 | |||
| 287 | /** | ||
| 288 | * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB). | ||
| 289 | * if MSB not set it is negative | ||
| 290 | * @param n length in bits | ||
| 291 | */ | ||
| 292 | 26844203 | static inline int get_xbits(GetBitContext *s, int n) | |
| 293 | { | ||
| 294 | register int sign; | ||
| 295 | register int32_t cache; | ||
| 296 | 26844203 | OPEN_READER(re, s); | |
| 297 | av_assert2(n>0 && n<=25); | ||
| 298 | 26844203 | UPDATE_CACHE(re, s); | |
| 299 | 26844203 | cache = GET_CACHE(re, s); | |
| 300 | 26844203 | sign = ~cache >> 31; | |
| 301 | 26844203 | LAST_SKIP_BITS(re, s, n); | |
| 302 | 26844203 | CLOSE_READER(re, s); | |
| 303 | 26844203 | return (NEG_USR32(sign ^ cache, n) ^ sign) - sign; | |
| 304 | } | ||
| 305 | |||
| 306 | 1534760 | static inline int get_xbits_le(GetBitContext *s, int n) | |
| 307 | { | ||
| 308 | register int sign; | ||
| 309 | register int32_t cache; | ||
| 310 | 1534760 | OPEN_READER(re, s); | |
| 311 | av_assert2(n>0 && n<=25); | ||
| 312 | 1534760 | UPDATE_CACHE_LE(re, s); | |
| 313 | 1534760 | cache = GET_CACHE(re, s); | |
| 314 | 1534760 | sign = sign_extend(~cache, n) >> 31; | |
| 315 | 1534760 | LAST_SKIP_BITS(re, s, n); | |
| 316 | 1534760 | CLOSE_READER(re, s); | |
| 317 | 1534760 | return (zero_extend(sign ^ cache, n) ^ sign) - sign; | |
| 318 | } | ||
| 319 | |||
| 320 | 33301718 | static inline int get_sbits(GetBitContext *s, int n) | |
| 321 | { | ||
| 322 | register int tmp; | ||
| 323 | 33301718 | OPEN_READER(re, s); | |
| 324 | av_assert2(n>0 && n<=25); | ||
| 325 | 33301718 | UPDATE_CACHE(re, s); | |
| 326 | 33301718 | tmp = SHOW_SBITS(re, s, n); | |
| 327 | 33301718 | LAST_SKIP_BITS(re, s, n); | |
| 328 | 33301718 | CLOSE_READER(re, s); | |
| 329 | 33301718 | return tmp; | |
| 330 | } | ||
| 331 | |||
| 332 | /** | ||
| 333 | * Read 1-25 bits. | ||
| 334 | */ | ||
| 335 | 269524870 | static inline unsigned int get_bits(GetBitContext *s, int n) | |
| 336 | { | ||
| 337 | register unsigned int tmp; | ||
| 338 | 269524870 | OPEN_READER(re, s); | |
| 339 | av_assert2(n>0 && n<=25); | ||
| 340 | 269524870 | UPDATE_CACHE(re, s); | |
| 341 | 269524870 | tmp = SHOW_UBITS(re, s, n); | |
| 342 | 269524870 | LAST_SKIP_BITS(re, s, n); | |
| 343 | 269524870 | CLOSE_READER(re, s); | |
| 344 | av_assert2(tmp < UINT64_C(1) << n); | ||
| 345 | 269524870 | return tmp; | |
| 346 | } | ||
| 347 | |||
| 348 | /** | ||
| 349 | * Read 0-25 bits. | ||
| 350 | */ | ||
| 351 | 762341 | static av_always_inline int get_bitsz(GetBitContext *s, int n) | |
| 352 | { | ||
| 353 |
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762341 | return n ? get_bits(s, n) : 0; |
| 354 | } | ||
| 355 | |||
| 356 | 718813 | static inline unsigned int get_bits_le(GetBitContext *s, int n) | |
| 357 | { | ||
| 358 | register int tmp; | ||
| 359 | 718813 | OPEN_READER(re, s); | |
| 360 | av_assert2(n>0 && n<=25); | ||
| 361 | 718813 | UPDATE_CACHE_LE(re, s); | |
| 362 | 718813 | tmp = SHOW_UBITS_LE(re, s, n); | |
| 363 | 718813 | LAST_SKIP_BITS(re, s, n); | |
| 364 | 718813 | CLOSE_READER(re, s); | |
| 365 | 718813 | return tmp; | |
| 366 | } | ||
| 367 | |||
| 368 | /** | ||
| 369 | * Show 1-25 bits. | ||
| 370 | */ | ||
| 371 | 114585663 | static inline unsigned int show_bits(GetBitContext *s, int n) | |
| 372 | { | ||
| 373 | register unsigned int tmp; | ||
| 374 | 114585663 | OPEN_READER_NOSIZE(re, s); | |
| 375 | av_assert2(n>0 && n<=25); | ||
| 376 | 114585663 | UPDATE_CACHE(re, s); | |
| 377 | 114585663 | tmp = SHOW_UBITS(re, s, n); | |
| 378 | 114585663 | return tmp; | |
| 379 | } | ||
| 380 | |||
| 381 | 111775863 | static inline void skip_bits(GetBitContext *s, int n) | |
| 382 | { | ||
| 383 | 111775863 | OPEN_READER(re, s); | |
| 384 | 111775863 | LAST_SKIP_BITS(re, s, n); | |
| 385 | 111775863 | CLOSE_READER(re, s); | |
| 386 | 111775863 | } | |
| 387 | |||
| 388 | 454301302 | static inline unsigned int get_bits1(GetBitContext *s) | |
| 389 | { | ||
| 390 | 454301302 | unsigned int index = s->index; | |
| 391 | 454301302 | uint8_t result = s->buffer[index >> 3]; | |
| 392 | #ifdef BITSTREAM_READER_LE | ||
| 393 | 265246943 | result >>= index & 7; | |
| 394 | 265246943 | result &= 1; | |
| 395 | #else | ||
| 396 | 189054359 | result <<= index & 7; | |
| 397 | 189054359 | result >>= 8 - 1; | |
| 398 | #endif | ||
| 399 | #if !UNCHECKED_BITSTREAM_READER | ||
| 400 |
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411521042 | if (s->index < s->size_in_bits_plus8) |
| 401 | #endif | ||
| 402 | 454285925 | index++; | |
| 403 | 454301302 | s->index = index; | |
| 404 | |||
| 405 | 454301302 | return result; | |
| 406 | } | ||
| 407 | |||
| 408 | 43260 | static inline unsigned int show_bits1(GetBitContext *s) | |
| 409 | { | ||
| 410 | 43260 | return show_bits(s, 1); | |
| 411 | } | ||
| 412 | |||
| 413 | 297769 | static inline void skip_bits1(GetBitContext *s) | |
| 414 | { | ||
| 415 | 297769 | skip_bits(s, 1); | |
| 416 | 297769 | } | |
| 417 | |||
| 418 | /** | ||
| 419 | * Read 0-32 bits. | ||
| 420 | */ | ||
| 421 | 56981746 | static inline unsigned int get_bits_long(GetBitContext *s, int n) | |
| 422 | { | ||
| 423 | av_assert2(n>=0 && n<=32); | ||
| 424 |
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56981746 | if (!n) { |
| 425 | 3404960 | return 0; | |
| 426 | } else if ((!HAVE_FAST_64BIT || av_builtin_constant_p(n <= MIN_CACHE_BITS)) | ||
| 427 | && n <= MIN_CACHE_BITS) { | ||
| 428 | return get_bits(s, n); | ||
| 429 | } else { | ||
| 430 | #if HAVE_FAST_64BIT | ||
| 431 | unsigned tmp; | ||
| 432 | 53576786 | OPEN_READER(re, s); | |
| 433 | 53576786 | UPDATE_CACHE_32(re, s); | |
| 434 | 53576786 | tmp = SHOW_UBITS(re, s, n); | |
| 435 | 53576786 | LAST_SKIP_BITS(re, s, n); | |
| 436 | 53576786 | CLOSE_READER(re, s); | |
| 437 | 53576786 | return tmp; | |
| 438 | #else | ||
| 439 | #ifdef BITSTREAM_READER_LE | ||
| 440 | unsigned ret = get_bits(s, 16); | ||
| 441 | return ret | (get_bits(s, n - 16) << 16); | ||
| 442 | #else | ||
| 443 | unsigned ret = get_bits(s, 16) << (n - 16); | ||
| 444 | return ret | get_bits(s, n - 16); | ||
| 445 | #endif | ||
| 446 | #endif | ||
| 447 | } | ||
| 448 | } | ||
| 449 | |||
| 450 | /** | ||
| 451 | * Read 0-64 bits. | ||
| 452 | */ | ||
| 453 | 11094 | static inline uint64_t get_bits64(GetBitContext *s, int n) | |
| 454 | { | ||
| 455 |
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11094 | if (n <= 32) { |
| 456 | 6375 | return get_bits_long(s, n); | |
| 457 | } else { | ||
| 458 | #ifdef BITSTREAM_READER_LE | ||
| 459 | 1 | uint64_t ret = get_bits_long(s, 32); | |
| 460 | 1 | return ret | (uint64_t) get_bits_long(s, n - 32) << 32; | |
| 461 | #else | ||
| 462 | 4718 | uint64_t ret = (uint64_t) get_bits_long(s, n - 32) << 32; | |
| 463 | 4718 | return ret | get_bits_long(s, 32); | |
| 464 | #endif | ||
| 465 | } | ||
| 466 | } | ||
| 467 | |||
| 468 | /** | ||
| 469 | * Read 0-32 bits as a signed integer. | ||
| 470 | */ | ||
| 471 | 4766298 | static inline int get_sbits_long(GetBitContext *s, int n) | |
| 472 | { | ||
| 473 | // sign_extend(x, 0) is undefined | ||
| 474 |
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4766298 | if (!n) |
| 475 | ✗ | return 0; | |
| 476 | |||
| 477 | 4766298 | return sign_extend(get_bits_long(s, n), n); | |
| 478 | } | ||
| 479 | |||
| 480 | /** | ||
| 481 | * Read 0-64 bits as a signed integer. | ||
| 482 | */ | ||
| 483 | 4624 | static inline int64_t get_sbits64(GetBitContext *s, int n) | |
| 484 | { | ||
| 485 | // sign_extend(x, 0) is undefined | ||
| 486 |
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4624 | if (!n) |
| 487 | ✗ | return 0; | |
| 488 | |||
| 489 | 4624 | return sign_extend64(get_bits64(s, n), n); | |
| 490 | } | ||
| 491 | |||
| 492 | /** | ||
| 493 | * Show 0-32 bits. | ||
| 494 | */ | ||
| 495 | 3489286 | static inline unsigned int show_bits_long(GetBitContext *s, int n) | |
| 496 | { | ||
| 497 |
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3489286 | if (n <= MIN_CACHE_BITS) { |
| 498 | 15900 | return show_bits(s, n); | |
| 499 | } else { | ||
| 500 | 3473386 | GetBitContext gb = *s; | |
| 501 | 3473386 | return get_bits_long(&gb, n); | |
| 502 | } | ||
| 503 | } | ||
| 504 | |||
| 505 | |||
| 506 | /** | ||
| 507 | * Initialize GetBitContext. | ||
| 508 | * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes | ||
| 509 | * larger than the actual read bits because some optimized bitstream | ||
| 510 | * readers read 32 or 64 bit at once and could read over the end | ||
| 511 | * @param bit_size the size of the buffer in bits | ||
| 512 | * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. | ||
| 513 | */ | ||
| 514 | 29798850 | static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer, | |
| 515 | int bit_size) | ||
| 516 | { | ||
| 517 | int buffer_size; | ||
| 518 | 29798850 | int ret = 0; | |
| 519 | |||
| 520 |
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29798850 | if (bit_size >= INT_MAX - FFMAX(7, AV_INPUT_BUFFER_PADDING_SIZE*8) || bit_size < 0 || !buffer) { |
| 521 | 4 | bit_size = 0; | |
| 522 | 4 | buffer = NULL; | |
| 523 | 4 | ret = AVERROR_INVALIDDATA; | |
| 524 | } | ||
| 525 | |||
| 526 | 29798850 | buffer_size = (bit_size + 7) >> 3; | |
| 527 | |||
| 528 | 29798850 | s->buffer = buffer; | |
| 529 | 29798850 | s->size_in_bits = bit_size; | |
| 530 | 29798850 | s->size_in_bits_plus8 = bit_size + 8; | |
| 531 | 29798850 | s->buffer_end = buffer + buffer_size; | |
| 532 | 29798850 | s->index = 0; | |
| 533 | |||
| 534 | 29798850 | return ret; | |
| 535 | } | ||
| 536 | |||
| 537 | /** | ||
| 538 | * Initialize GetBitContext. | ||
| 539 | * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes | ||
| 540 | * larger than the actual read bits because some optimized bitstream | ||
| 541 | * readers read 32 or 64 bit at once and could read over the end | ||
| 542 | * @param byte_size the size of the buffer in bytes | ||
| 543 | * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. | ||
| 544 | */ | ||
| 545 | 610871 | static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer, | |
| 546 | int byte_size) | ||
| 547 | { | ||
| 548 |
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610871 | if (byte_size > INT_MAX / 8 || byte_size < 0) |
| 549 | ✗ | byte_size = -1; | |
| 550 | 610871 | return init_get_bits(s, buffer, byte_size * 8); | |
| 551 | } | ||
| 552 | |||
| 553 | 200 | static inline int init_get_bits8_le(GetBitContext *s, const uint8_t *buffer, | |
| 554 | int byte_size) | ||
| 555 | { | ||
| 556 |
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200 | if (byte_size > INT_MAX / 8 || byte_size < 0) |
| 557 | ✗ | byte_size = -1; | |
| 558 | 200 | return init_get_bits(s, buffer, byte_size * 8); | |
| 559 | } | ||
| 560 | |||
| 561 | 280705 | static inline const uint8_t *align_get_bits(GetBitContext *s) | |
| 562 | { | ||
| 563 | 280705 | int n = -get_bits_count(s) & 7; | |
| 564 |
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280705 | if (n) |
| 565 | 95177 | skip_bits(s, n); | |
| 566 | 280705 | return s->buffer + (s->index >> 3); | |
| 567 | } | ||
| 568 | |||
| 569 | /** | ||
| 570 | * If the vlc code is invalid and max_depth=1, then no bits will be removed. | ||
| 571 | * If the vlc code is invalid and max_depth>1, then the number of bits removed | ||
| 572 | * is undefined. | ||
| 573 | */ | ||
| 574 | #define GET_VLC(code, name, gb, table, bits, max_depth) \ | ||
| 575 | do { \ | ||
| 576 | int n, nb_bits; \ | ||
| 577 | unsigned int index; \ | ||
| 578 | \ | ||
| 579 | index = SHOW_UBITS(name, gb, bits); \ | ||
| 580 | code = table[index].sym; \ | ||
| 581 | n = table[index].len; \ | ||
| 582 | \ | ||
| 583 | if (max_depth > 1 && n < 0) { \ | ||
| 584 | LAST_SKIP_BITS(name, gb, bits); \ | ||
| 585 | UPDATE_CACHE(name, gb); \ | ||
| 586 | \ | ||
| 587 | nb_bits = -n; \ | ||
| 588 | \ | ||
| 589 | index = SHOW_UBITS(name, gb, nb_bits) + code; \ | ||
| 590 | code = table[index].sym; \ | ||
| 591 | n = table[index].len; \ | ||
| 592 | if (max_depth > 2 && n < 0) { \ | ||
| 593 | LAST_SKIP_BITS(name, gb, nb_bits); \ | ||
| 594 | UPDATE_CACHE(name, gb); \ | ||
| 595 | \ | ||
| 596 | nb_bits = -n; \ | ||
| 597 | \ | ||
| 598 | index = SHOW_UBITS(name, gb, nb_bits) + code; \ | ||
| 599 | code = table[index].sym; \ | ||
| 600 | n = table[index].len; \ | ||
| 601 | } \ | ||
| 602 | } \ | ||
| 603 | SKIP_BITS(name, gb, n); \ | ||
| 604 | } while (0) | ||
| 605 | |||
| 606 | #define GET_RL_VLC(level, run, name, gb, table, bits, \ | ||
| 607 | max_depth, need_update) \ | ||
| 608 | do { \ | ||
| 609 | int n, nb_bits; \ | ||
| 610 | unsigned int index; \ | ||
| 611 | \ | ||
| 612 | index = SHOW_UBITS(name, gb, bits); \ | ||
| 613 | level = table[index].level; \ | ||
| 614 | n = table[index].len; \ | ||
| 615 | \ | ||
| 616 | if (max_depth > 1 && n < 0) { \ | ||
| 617 | SKIP_BITS(name, gb, bits); \ | ||
| 618 | if (need_update) { \ | ||
| 619 | UPDATE_CACHE(name, gb); \ | ||
| 620 | } \ | ||
| 621 | \ | ||
| 622 | nb_bits = -n; \ | ||
| 623 | \ | ||
| 624 | index = SHOW_UBITS(name, gb, nb_bits) + level; \ | ||
| 625 | level = table[index].level; \ | ||
| 626 | n = table[index].len; \ | ||
| 627 | if (max_depth > 2 && n < 0) { \ | ||
| 628 | LAST_SKIP_BITS(name, gb, nb_bits); \ | ||
| 629 | if (need_update) { \ | ||
| 630 | UPDATE_CACHE(name, gb); \ | ||
| 631 | } \ | ||
| 632 | nb_bits = -n; \ | ||
| 633 | \ | ||
| 634 | index = SHOW_UBITS(name, gb, nb_bits) + level; \ | ||
| 635 | level = table[index].level; \ | ||
| 636 | n = table[index].len; \ | ||
| 637 | } \ | ||
| 638 | } \ | ||
| 639 | run = table[index].run; \ | ||
| 640 | SKIP_BITS(name, gb, n); \ | ||
| 641 | } while (0) | ||
| 642 | |||
| 643 | /** | ||
| 644 | * Parse a vlc code. | ||
| 645 | * @param bits is the number of bits which will be read at once, must be | ||
| 646 | * identical to nb_bits in vlc_init() | ||
| 647 | * @param max_depth is the number of times bits bits must be read to completely | ||
| 648 | * read the longest vlc code | ||
| 649 | * = (max_vlc_length + bits - 1) / bits | ||
| 650 | * @returns the code parsed or -1 if no vlc matches | ||
| 651 | */ | ||
| 652 | 289668907 | static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table, | |
| 653 | int bits, int max_depth) | ||
| 654 | { | ||
| 655 | int code; | ||
| 656 | |||
| 657 | 289668907 | OPEN_READER(re, s); | |
| 658 | 289668907 | UPDATE_CACHE(re, s); | |
| 659 | |||
| 660 |
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289668907 | GET_VLC(code, re, s, table, bits, max_depth); |
| 661 | |||
| 662 | 289668907 | CLOSE_READER(re, s); | |
| 663 | |||
| 664 | 289668907 | return code; | |
| 665 | } | ||
| 666 | |||
| 667 | static inline int get_vlc_multi(GetBitContext *s, uint8_t *dst, | ||
| 668 | const VLC_MULTI_ELEM *const Jtable, | ||
| 669 | const VLCElem *const table, | ||
| 670 | const int bits, const int max_depth) | ||
| 671 | { | ||
| 672 | dst[0] = get_vlc2(s, table, bits, max_depth); | ||
| 673 | return 1; | ||
| 674 | } | ||
| 675 | |||
| 676 | 378521 | static inline int decode012(GetBitContext *gb) | |
| 677 | { | ||
| 678 | int n; | ||
| 679 | 378521 | n = get_bits1(gb); | |
| 680 |
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378521 | if (n == 0) |
| 681 | 263666 | return 0; | |
| 682 | else | ||
| 683 | 114855 | return get_bits1(gb) + 1; | |
| 684 | } | ||
| 685 | |||
| 686 | 180374 | static inline int decode210(GetBitContext *gb) | |
| 687 | { | ||
| 688 |
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180374 | if (get_bits1(gb)) |
| 689 | 131153 | return 0; | |
| 690 | else | ||
| 691 | 49221 | return 2 - get_bits1(gb); | |
| 692 | } | ||
| 693 | |||
| 694 | 269588738 | static inline int get_bits_left(GetBitContext *gb) | |
| 695 | { | ||
| 696 | 269588738 | return gb->size_in_bits - get_bits_count(gb); | |
| 697 | } | ||
| 698 | |||
| 699 | 133246 | static inline int skip_1stop_8data_bits(GetBitContext *gb) | |
| 700 | { | ||
| 701 |
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133246 | if (get_bits_left(gb) <= 0) |
| 702 | ✗ | return AVERROR_INVALIDDATA; | |
| 703 | |||
| 704 |
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136360 | while (get_bits1(gb)) { |
| 705 | 3114 | skip_bits(gb, 8); | |
| 706 |
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3114 | if (get_bits_left(gb) <= 0) |
| 707 | ✗ | return AVERROR_INVALIDDATA; | |
| 708 | } | ||
| 709 | |||
| 710 | 133246 | return 0; | |
| 711 | } | ||
| 712 | |||
| 713 | #endif // CACHED_BITSTREAM_READER | ||
| 714 | |||
| 715 | #endif /* AVCODEC_GET_BITS_H */ | ||
| 716 |