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 libavcodec/bitstream.h 23 * bitstream api header. 24 */ 25 26#ifndef AVCODEC_BITSTREAM_H 27#define AVCODEC_BITSTREAM_H 28 29#include <stdint.h> 30#include <stdlib.h> 31#include <assert.h> 32#include "libavutil/bswap.h" 33#include "libavutil/common.h" 34#include "libavutil/intreadwrite.h" 35#include "libavutil/log.h" 36 37#if defined(ALT_BITSTREAM_READER_LE) && !defined(ALT_BITSTREAM_READER) 38# define ALT_BITSTREAM_READER 39#endif 40 41//#define ALT_BITSTREAM_WRITER 42//#define ALIGNED_BITSTREAM_WRITER 43#if !defined(LIBMPEG2_BITSTREAM_READER) && !defined(A32_BITSTREAM_READER) && !defined(ALT_BITSTREAM_READER) 44# if ARCH_ARM 45# define A32_BITSTREAM_READER 46# else 47# define ALT_BITSTREAM_READER 48//#define LIBMPEG2_BITSTREAM_READER 49//#define A32_BITSTREAM_READER 50# endif 51#endif 52 53extern const uint8_t ff_reverse[256]; 54 55#if ARCH_X86 56// avoid +32 for shift optimization (gcc should do that ...) 57static inline int32_t NEG_SSR32( int32_t a, int8_t s){ 58 __asm__ ("sarl %1, %0\n\t" 59 : "+r" (a) 60 : "ic" ((uint8_t)(-s)) 61 ); 62 return a; 63} 64static inline uint32_t NEG_USR32(uint32_t a, int8_t s){ 65 __asm__ ("shrl %1, %0\n\t" 66 : "+r" (a) 67 : "ic" ((uint8_t)(-s)) 68 ); 69 return a; 70} 71#else 72# define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s))) 73# define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s))) 74#endif 75 76/* bit output */ 77 78/* buf and buf_end must be present and used by every alternative writer. */ 79typedef struct PutBitContext { 80#ifdef ALT_BITSTREAM_WRITER 81 uint8_t *buf, *buf_end; 82 int index; 83#else 84 uint32_t bit_buf; 85 int bit_left; 86 uint8_t *buf, *buf_ptr, *buf_end; 87#endif 88 int size_in_bits; 89} PutBitContext; 90 91static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size) 92{ 93 if(buffer_size < 0) { 94 buffer_size = 0; 95 buffer = NULL; 96 } 97 98 s->size_in_bits= 8*buffer_size; 99 s->buf = buffer; 100 s->buf_end = s->buf + buffer_size; 101#ifdef ALT_BITSTREAM_WRITER 102 s->index=0; 103 ((uint32_t*)(s->buf))[0]=0; 104// memset(buffer, 0, buffer_size); 105#else 106 s->buf_ptr = s->buf; 107 s->bit_left=32; 108 s->bit_buf=0; 109#endif 110} 111 112/* return the number of bits output */ 113static inline int put_bits_count(PutBitContext *s) 114{ 115#ifdef ALT_BITSTREAM_WRITER 116 return s->index; 117#else 118 return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left; 119#endif 120} 121 122/* pad the end of the output stream with zeros */ 123static inline void flush_put_bits(PutBitContext *s) 124{ 125#ifdef ALT_BITSTREAM_WRITER 126 align_put_bits(s); 127#else 128#ifndef BITSTREAM_WRITER_LE 129 s->bit_buf<<= s->bit_left; 130#endif 131 while (s->bit_left < 32) { 132 /* XXX: should test end of buffer */ 133#ifdef BITSTREAM_WRITER_LE 134 *s->buf_ptr++=s->bit_buf; 135 s->bit_buf>>=8; 136#else 137 *s->buf_ptr++=s->bit_buf >> 24; 138 s->bit_buf<<=8; 139#endif 140 s->bit_left+=8; 141 } 142 s->bit_left=32; 143 s->bit_buf=0; 144#endif 145} 146 147void align_put_bits(PutBitContext *s); 148void ff_put_string(PutBitContext * pbc, const char *s, int put_zero); 149void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length); 150 151/* bit input */ 152/* buffer, buffer_end and size_in_bits must be present and used by every reader */ 153typedef struct GetBitContext { 154 const uint8_t *buffer, *buffer_end; 155#ifdef ALT_BITSTREAM_READER 156 int index; 157#elif defined LIBMPEG2_BITSTREAM_READER 158 uint8_t *buffer_ptr; 159 uint32_t cache; 160 int bit_count; 161#elif defined A32_BITSTREAM_READER 162 uint32_t *buffer_ptr; 163 uint32_t cache0; 164 uint32_t cache1; 165 int bit_count; 166#endif 167 int size_in_bits; 168} GetBitContext; 169 170#define VLC_TYPE int16_t 171 172typedef struct VLC { 173 int bits; 174 VLC_TYPE (*table)[2]; ///< code, bits 175 int table_size, table_allocated; 176} VLC; 177 178typedef struct RL_VLC_ELEM { 179 int16_t level; 180 int8_t len; 181 uint8_t run; 182} RL_VLC_ELEM; 183 184#ifndef ALT_BITSTREAM_WRITER 185static inline void put_bits(PutBitContext *s, int n, unsigned int value) 186{ 187 unsigned int bit_buf; 188 int bit_left; 189 190 // printf("put_bits=%d %x\n", n, value); 191 assert(n == 32 || value < (1U << n)); 192 193 bit_buf = s->bit_buf; 194 bit_left = s->bit_left; 195 196 // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf); 197 /* XXX: optimize */ 198#ifdef BITSTREAM_WRITER_LE 199 bit_buf |= value << (32 - bit_left); 200 if (n >= bit_left) { 201#if !HAVE_FAST_UNALIGNED 202 if (3 & (intptr_t) s->buf_ptr) { 203 AV_WL32(s->buf_ptr, bit_buf); 204 } else 205#endif 206 *(uint32_t *)s->buf_ptr = le2me_32(bit_buf); 207 s->buf_ptr+=4; 208 bit_buf = (bit_left==32)?0:value >> bit_left; 209 bit_left+=32; 210 } 211 bit_left-=n; 212#else 213 if (n < bit_left) { 214 bit_buf = (bit_buf<<n) | value; 215 bit_left-=n; 216 } else { 217 bit_buf<<=bit_left; 218 bit_buf |= value >> (n - bit_left); 219#if !HAVE_FAST_UNALIGNED 220 if (3 & (intptr_t) s->buf_ptr) { 221 AV_WB32(s->buf_ptr, bit_buf); 222 } else 223#endif 224 *(uint32_t *)s->buf_ptr = be2me_32(bit_buf); 225 //printf("bitbuf = %08x\n", bit_buf); 226 s->buf_ptr+=4; 227 bit_left+=32 - n; 228 bit_buf = value; 229 } 230#endif 231 232 s->bit_buf = bit_buf; 233 s->bit_left = bit_left; 234} 235#endif 236 237 238#ifdef ALT_BITSTREAM_WRITER 239static inline void put_bits(PutBitContext *s, int n, unsigned int value) 240{ 241# ifdef ALIGNED_BITSTREAM_WRITER 242# if ARCH_X86 243 __asm__ volatile( 244 "movl %0, %%ecx \n\t" 245 "xorl %%eax, %%eax \n\t" 246 "shrdl %%cl, %1, %%eax \n\t" 247 "shrl %%cl, %1 \n\t" 248 "movl %0, %%ecx \n\t" 249 "shrl $3, %%ecx \n\t" 250 "andl $0xFFFFFFFC, %%ecx \n\t" 251 "bswapl %1 \n\t" 252 "orl %1, (%2, %%ecx) \n\t" 253 "bswapl %%eax \n\t" 254 "addl %3, %0 \n\t" 255 "movl %%eax, 4(%2, %%ecx) \n\t" 256 : "=&r" (s->index), "=&r" (value) 257 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n)) 258 : "%eax", "%ecx" 259 ); 260# else 261 int index= s->index; 262 uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5); 263 264 value<<= 32-n; 265 266 ptr[0] |= be2me_32(value>>(index&31)); 267 ptr[1] = be2me_32(value<<(32-(index&31))); 268//if(n>24) printf("%d %d\n", n, value); 269 index+= n; 270 s->index= index; 271# endif 272# else //ALIGNED_BITSTREAM_WRITER 273# if ARCH_X86 274 __asm__ volatile( 275 "movl $7, %%ecx \n\t" 276 "andl %0, %%ecx \n\t" 277 "addl %3, %%ecx \n\t" 278 "negl %%ecx \n\t" 279 "shll %%cl, %1 \n\t" 280 "bswapl %1 \n\t" 281 "movl %0, %%ecx \n\t" 282 "shrl $3, %%ecx \n\t" 283 "orl %1, (%%ecx, %2) \n\t" 284 "addl %3, %0 \n\t" 285 "movl $0, 4(%%ecx, %2) \n\t" 286 : "=&r" (s->index), "=&r" (value) 287 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value) 288 : "%ecx" 289 ); 290# else 291 int index= s->index; 292 uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3)); 293 294 ptr[0] |= be2me_32(value<<(32-n-(index&7) )); 295 ptr[1] = 0; 296//if(n>24) printf("%d %d\n", n, value); 297 index+= n; 298 s->index= index; 299# endif 300# endif //!ALIGNED_BITSTREAM_WRITER 301} 302#endif 303 304static inline void put_sbits(PutBitContext *pb, int bits, int32_t val) 305{ 306 assert(bits >= 0 && bits <= 31); 307 308 put_bits(pb, bits, val & ((1<<bits)-1)); 309} 310 311 312static inline uint8_t* pbBufPtr(PutBitContext *s) 313{ 314#ifdef ALT_BITSTREAM_WRITER 315 return s->buf + (s->index>>3); 316#else 317 return s->buf_ptr; 318#endif 319} 320 321/** 322 * 323 * PutBitContext must be flushed & aligned to a byte boundary before calling this. 324 */ 325static inline void skip_put_bytes(PutBitContext *s, int n){ 326 assert((put_bits_count(s)&7)==0); 327#ifdef ALT_BITSTREAM_WRITER 328 FIXME may need some cleaning of the buffer 329 s->index += n<<3; 330#else 331 assert(s->bit_left==32); 332 s->buf_ptr += n; 333#endif 334} 335 336/** 337 * Skips the given number of bits. 338 * Must only be used if the actual values in the bitstream do not matter. 339 */ 340static inline void skip_put_bits(PutBitContext *s, int n){ 341#ifdef ALT_BITSTREAM_WRITER 342 s->index += n; 343#else 344 s->bit_left -= n; 345 s->buf_ptr-= s->bit_left>>5; 346 s->bit_left &= 31; 347#endif 348} 349 350/** 351 * Changes the end of the buffer. 352 */ 353static inline void set_put_bits_buffer_size(PutBitContext *s, int size){ 354 s->buf_end= s->buf + size; 355} 356 357/* Bitstream reader API docs: 358name 359 arbitrary name which is used as prefix for the internal variables 360 361gb 362 getbitcontext 363 364OPEN_READER(name, gb) 365 loads gb into local variables 366 367CLOSE_READER(name, gb) 368 stores local vars in gb 369 370UPDATE_CACHE(name, gb) 371 refills the internal cache from the bitstream 372 after this call at least MIN_CACHE_BITS will be available, 373 374GET_CACHE(name, gb) 375 will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit) 376 377SHOW_UBITS(name, gb, num) 378 will return the next num bits 379 380SHOW_SBITS(name, gb, num) 381 will return the next num bits and do sign extension 382 383SKIP_BITS(name, gb, num) 384 will skip over the next num bits 385 note, this is equivalent to SKIP_CACHE; SKIP_COUNTER 386 387SKIP_CACHE(name, gb, num) 388 will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER) 389 390SKIP_COUNTER(name, gb, num) 391 will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS) 392 393LAST_SKIP_CACHE(name, gb, num) 394 will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing 395 396LAST_SKIP_BITS(name, gb, num) 397 is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER 398 399for examples see get_bits, show_bits, skip_bits, get_vlc 400*/ 401 402#ifdef ALT_BITSTREAM_READER 403# define MIN_CACHE_BITS 25 404 405# define OPEN_READER(name, gb)\ 406 int name##_index= (gb)->index;\ 407 int name##_cache= 0;\ 408 409# define CLOSE_READER(name, gb)\ 410 (gb)->index= name##_index;\ 411 412# ifdef ALT_BITSTREAM_READER_LE 413# define UPDATE_CACHE(name, gb)\ 414 name##_cache= AV_RL32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\ 415 416# define SKIP_CACHE(name, gb, num)\ 417 name##_cache >>= (num); 418# else 419# define UPDATE_CACHE(name, gb)\ 420 name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\ 421 422# define SKIP_CACHE(name, gb, num)\ 423 name##_cache <<= (num); 424# endif 425 426// FIXME name? 427# define SKIP_COUNTER(name, gb, num)\ 428 name##_index += (num);\ 429 430# define SKIP_BITS(name, gb, num)\ 431 {\ 432 SKIP_CACHE(name, gb, num)\ 433 SKIP_COUNTER(name, gb, num)\ 434 }\ 435 436# define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num) 437# define LAST_SKIP_CACHE(name, gb, num) ; 438 439# ifdef ALT_BITSTREAM_READER_LE 440# define SHOW_UBITS(name, gb, num)\ 441 ((name##_cache) & (NEG_USR32(0xffffffff,num))) 442 443# define SHOW_SBITS(name, gb, num)\ 444 NEG_SSR32((name##_cache)<<(32-(num)), num) 445# else 446# define SHOW_UBITS(name, gb, num)\ 447 NEG_USR32(name##_cache, num) 448 449# define SHOW_SBITS(name, gb, num)\ 450 NEG_SSR32(name##_cache, num) 451# endif 452 453# define GET_CACHE(name, gb)\ 454 ((uint32_t)name##_cache) 455 456static inline int get_bits_count(GetBitContext *s){ 457 return s->index; 458} 459 460static inline void skip_bits_long(GetBitContext *s, int n){ 461 s->index += n; 462} 463 464#elif defined LIBMPEG2_BITSTREAM_READER 465//libmpeg2 like reader 466 467# define MIN_CACHE_BITS 17 468 469# define OPEN_READER(name, gb)\ 470 int name##_bit_count=(gb)->bit_count;\ 471 int name##_cache= (gb)->cache;\ 472 uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\ 473 474# define CLOSE_READER(name, gb)\ 475 (gb)->bit_count= name##_bit_count;\ 476 (gb)->cache= name##_cache;\ 477 (gb)->buffer_ptr= name##_buffer_ptr;\ 478 479# define UPDATE_CACHE(name, gb)\ 480 if(name##_bit_count >= 0){\ 481 name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count; \ 482 name##_buffer_ptr+=2;\ 483 name##_bit_count-= 16;\ 484 }\ 485 486# define SKIP_CACHE(name, gb, num)\ 487 name##_cache <<= (num);\ 488 489# define SKIP_COUNTER(name, gb, num)\ 490 name##_bit_count += (num);\ 491 492# define SKIP_BITS(name, gb, num)\ 493 {\ 494 SKIP_CACHE(name, gb, num)\ 495 SKIP_COUNTER(name, gb, num)\ 496 }\ 497 498# define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num) 499# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num) 500 501# define SHOW_UBITS(name, gb, num)\ 502 NEG_USR32(name##_cache, num) 503 504# define SHOW_SBITS(name, gb, num)\ 505 NEG_SSR32(name##_cache, num) 506 507# define GET_CACHE(name, gb)\ 508 ((uint32_t)name##_cache) 509 510static inline int get_bits_count(GetBitContext *s){ 511 return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count; 512} 513 514static inline void skip_bits_long(GetBitContext *s, int n){ 515 OPEN_READER(re, s) 516 re_bit_count += n; 517 re_buffer_ptr += 2*(re_bit_count>>4); 518 re_bit_count &= 15; 519 re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count); 520 UPDATE_CACHE(re, s) 521 CLOSE_READER(re, s) 522} 523 524#elif defined A32_BITSTREAM_READER 525 526# define MIN_CACHE_BITS 32 527 528# define OPEN_READER(name, gb)\ 529 int name##_bit_count=(gb)->bit_count;\ 530 uint32_t name##_cache0= (gb)->cache0;\ 531 uint32_t name##_cache1= (gb)->cache1;\ 532 uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\ 533 534# define CLOSE_READER(name, gb)\ 535 (gb)->bit_count= name##_bit_count;\ 536 (gb)->cache0= name##_cache0;\ 537 (gb)->cache1= name##_cache1;\ 538 (gb)->buffer_ptr= name##_buffer_ptr;\ 539 540# define UPDATE_CACHE(name, gb)\ 541 if(name##_bit_count > 0){\ 542 const uint32_t next= be2me_32( *name##_buffer_ptr );\ 543 name##_cache0 |= NEG_USR32(next,name##_bit_count);\ 544 name##_cache1 |= next<<name##_bit_count;\ 545 name##_buffer_ptr++;\ 546 name##_bit_count-= 32;\ 547 }\ 548 549#if ARCH_X86 550# define SKIP_CACHE(name, gb, num)\ 551 __asm__(\ 552 "shldl %2, %1, %0 \n\t"\ 553 "shll %2, %1 \n\t"\ 554 : "+r" (name##_cache0), "+r" (name##_cache1)\ 555 : "Ic" ((uint8_t)(num))\ 556 ); 557#else 558# define SKIP_CACHE(name, gb, num)\ 559 name##_cache0 <<= (num);\ 560 name##_cache0 |= NEG_USR32(name##_cache1,num);\ 561 name##_cache1 <<= (num); 562#endif 563 564# define SKIP_COUNTER(name, gb, num)\ 565 name##_bit_count += (num);\ 566 567# define SKIP_BITS(name, gb, num)\ 568 {\ 569 SKIP_CACHE(name, gb, num)\ 570 SKIP_COUNTER(name, gb, num)\ 571 }\ 572 573# define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num) 574# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num) 575 576# define SHOW_UBITS(name, gb, num)\ 577 NEG_USR32(name##_cache0, num) 578 579# define SHOW_SBITS(name, gb, num)\ 580 NEG_SSR32(name##_cache0, num) 581 582# define GET_CACHE(name, gb)\ 583 (name##_cache0) 584 585static inline int get_bits_count(GetBitContext *s){ 586 return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count; 587} 588 589static inline void skip_bits_long(GetBitContext *s, int n){ 590 OPEN_READER(re, s) 591 re_bit_count += n; 592 re_buffer_ptr += re_bit_count>>5; 593 re_bit_count &= 31; 594 re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count; 595 re_cache1 = 0; 596 UPDATE_CACHE(re, s) 597 CLOSE_READER(re, s) 598} 599 600#endif 601 602/** 603 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB). 604 * if MSB not set it is negative 605 * @param n length in bits 606 * @author BERO 607 */ 608static inline int get_xbits(GetBitContext *s, int n){ 609 register int sign; 610 register int32_t cache; 611 OPEN_READER(re, s) 612 UPDATE_CACHE(re, s) 613 cache = GET_CACHE(re,s); 614 sign=(~cache)>>31; 615 LAST_SKIP_BITS(re, s, n) 616 CLOSE_READER(re, s) 617 return (NEG_USR32(sign ^ cache, n) ^ sign) - sign; 618} 619 620static inline int get_sbits(GetBitContext *s, int n){ 621 register int tmp; 622 OPEN_READER(re, s) 623 UPDATE_CACHE(re, s) 624 tmp= SHOW_SBITS(re, s, n); 625 LAST_SKIP_BITS(re, s, n) 626 CLOSE_READER(re, s) 627 return tmp; 628} 629 630/** 631 * reads 1-17 bits. 632 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't 633 */ 634static inline unsigned int get_bits(GetBitContext *s, int n){ 635 register int tmp; 636 OPEN_READER(re, s) 637 UPDATE_CACHE(re, s) 638 tmp= SHOW_UBITS(re, s, n); 639 LAST_SKIP_BITS(re, s, n) 640 CLOSE_READER(re, s) 641 return tmp; 642} 643 644/** 645 * shows 1-17 bits. 646 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't 647 */ 648static inline unsigned int show_bits(GetBitContext *s, int n){ 649 register int tmp; 650 OPEN_READER(re, s) 651 UPDATE_CACHE(re, s) 652 tmp= SHOW_UBITS(re, s, n); 653// CLOSE_READER(re, s) 654 return tmp; 655} 656 657static inline void skip_bits(GetBitContext *s, int n){ 658 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :)) 659 OPEN_READER(re, s) 660 UPDATE_CACHE(re, s) 661 LAST_SKIP_BITS(re, s, n) 662 CLOSE_READER(re, s) 663} 664 665static inline unsigned int get_bits1(GetBitContext *s){ 666#ifdef ALT_BITSTREAM_READER 667 int index= s->index; 668 uint8_t result= s->buffer[ index>>3 ]; 669#ifdef ALT_BITSTREAM_READER_LE 670 result>>= (index&0x07); 671 result&= 1; 672#else 673 result<<= (index&0x07); 674 result>>= 8 - 1; 675#endif 676 index++; 677 s->index= index; 678 679 return result; 680#else 681 return get_bits(s, 1); 682#endif 683} 684 685static inline unsigned int show_bits1(GetBitContext *s){ 686 return show_bits(s, 1); 687} 688 689static inline void skip_bits1(GetBitContext *s){ 690 skip_bits(s, 1); 691} 692 693/** 694 * reads 0-32 bits. 695 */ 696static inline unsigned int get_bits_long(GetBitContext *s, int n){ 697 if(n<=17) return get_bits(s, n); 698 else{ 699#ifdef ALT_BITSTREAM_READER_LE 700 int ret= get_bits(s, 16); 701 return ret | (get_bits(s, n-16) << 16); 702#else 703 int ret= get_bits(s, 16) << (n-16); 704 return ret | get_bits(s, n-16); 705#endif 706 } 707} 708 709/** 710 * shows 0-32 bits. 711 */ 712static inline unsigned int show_bits_long(GetBitContext *s, int n){ 713 if(n<=17) return show_bits(s, n); 714 else{ 715 GetBitContext gb= *s; 716 int ret= get_bits_long(s, n); 717 *s= gb; 718 return ret; 719 } 720} 721 722static inline int check_marker(GetBitContext *s, const char *msg) 723{ 724 int bit= get_bits1(s); 725 if(!bit) 726 av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg); 727 728 return bit; 729} 730 731/** 732 * init GetBitContext. 733 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits 734 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end 735 * @param bit_size the size of the buffer in bits 736 */ 737static inline void init_get_bits(GetBitContext *s, 738 const uint8_t *buffer, int bit_size) 739{ 740 int buffer_size= (bit_size+7)>>3; 741 if(buffer_size < 0 || bit_size < 0) { 742 buffer_size = bit_size = 0; 743 buffer = NULL; 744 } 745 746 s->buffer= buffer; 747 s->size_in_bits= bit_size; 748 s->buffer_end= buffer + buffer_size; 749#ifdef ALT_BITSTREAM_READER 750 s->index=0; 751#elif defined LIBMPEG2_BITSTREAM_READER 752 s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1)); 753 s->bit_count = 16 + 8*((intptr_t)buffer&1); 754 skip_bits_long(s, 0); 755#elif defined A32_BITSTREAM_READER 756 s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3)); 757 s->bit_count = 32 + 8*((intptr_t)buffer&3); 758 skip_bits_long(s, 0); 759#endif 760} 761 762static inline void align_get_bits(GetBitContext *s) 763{ 764 int n= (-get_bits_count(s)) & 7; 765 if(n) skip_bits(s, n); 766} 767 768#define init_vlc(vlc, nb_bits, nb_codes,\ 769 bits, bits_wrap, bits_size,\ 770 codes, codes_wrap, codes_size,\ 771 flags)\ 772 init_vlc_sparse(vlc, nb_bits, nb_codes,\ 773 bits, bits_wrap, bits_size,\ 774 codes, codes_wrap, codes_size,\ 775 NULL, 0, 0, flags) 776 777int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, 778 const void *bits, int bits_wrap, int bits_size, 779 const void *codes, int codes_wrap, int codes_size, 780 const void *symbols, int symbols_wrap, int symbols_size, 781 int flags); 782#define INIT_VLC_USE_STATIC 1 ///< VERY strongly deprecated and forbidden 783#define INIT_VLC_LE 2 784#define INIT_VLC_USE_NEW_STATIC 4 785void free_vlc(VLC *vlc); 786 787#define INIT_VLC_STATIC(vlc, bits, a,b,c,d,e,f,g, static_size)\ 788{\ 789 static VLC_TYPE table[static_size][2];\ 790 (vlc)->table= table;\ 791 (vlc)->table_allocated= static_size;\ 792 init_vlc(vlc, bits, a,b,c,d,e,f,g, INIT_VLC_USE_NEW_STATIC);\ 793} 794 795 796/** 797 * 798 * if the vlc code is invalid and max_depth=1 than no bits will be removed 799 * if the vlc code is invalid and max_depth>1 than the number of bits removed 800 * is undefined 801 */ 802#define GET_VLC(code, name, gb, table, bits, max_depth)\ 803{\ 804 int n, index, nb_bits;\ 805\ 806 index= SHOW_UBITS(name, gb, bits);\ 807 code = table[index][0];\ 808 n = table[index][1];\ 809\ 810 if(max_depth > 1 && n < 0){\ 811 LAST_SKIP_BITS(name, gb, bits)\ 812 UPDATE_CACHE(name, gb)\ 813\ 814 nb_bits = -n;\ 815\ 816 index= SHOW_UBITS(name, gb, nb_bits) + code;\ 817 code = table[index][0];\ 818 n = table[index][1];\ 819 if(max_depth > 2 && n < 0){\ 820 LAST_SKIP_BITS(name, gb, nb_bits)\ 821 UPDATE_CACHE(name, gb)\ 822\ 823 nb_bits = -n;\ 824\ 825 index= SHOW_UBITS(name, gb, nb_bits) + code;\ 826 code = table[index][0];\ 827 n = table[index][1];\ 828 }\ 829 }\ 830 SKIP_BITS(name, gb, n)\ 831} 832 833#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\ 834{\ 835 int n, index, nb_bits;\ 836\ 837 index= SHOW_UBITS(name, gb, bits);\ 838 level = table[index].level;\ 839 n = table[index].len;\ 840\ 841 if(max_depth > 1 && n < 0){\ 842 SKIP_BITS(name, gb, bits)\ 843 if(need_update){\ 844 UPDATE_CACHE(name, gb)\ 845 }\ 846\ 847 nb_bits = -n;\ 848\ 849 index= SHOW_UBITS(name, gb, nb_bits) + level;\ 850 level = table[index].level;\ 851 n = table[index].len;\ 852 }\ 853 run= table[index].run;\ 854 SKIP_BITS(name, gb, n)\ 855} 856 857 858/** 859 * parses a vlc code, faster then get_vlc() 860 * @param bits is the number of bits which will be read at once, must be 861 * identical to nb_bits in init_vlc() 862 * @param max_depth is the number of times bits bits must be read to completely 863 * read the longest vlc code 864 * = (max_vlc_length + bits - 1) / bits 865 */ 866static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2], 867 int bits, int max_depth) 868{ 869 int code; 870 871 OPEN_READER(re, s) 872 UPDATE_CACHE(re, s) 873 874 GET_VLC(code, re, s, table, bits, max_depth) 875 876 CLOSE_READER(re, s) 877 return code; 878} 879 880//#define TRACE 881 882#ifdef TRACE 883static inline void print_bin(int bits, int n){ 884 int i; 885 886 for(i=n-1; i>=0; i--){ 887 av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1); 888 } 889 for(i=n; i<24; i++) 890 av_log(NULL, AV_LOG_DEBUG, " "); 891} 892 893static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){ 894 int r= get_bits(s, n); 895 896 print_bin(r, n); 897 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d bit @%5d in %s %s:%d\n", r, n, r, get_bits_count(s)-n, file, func, line); 898 return r; 899} 900static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){ 901 int show= show_bits(s, 24); 902 int pos= get_bits_count(s); 903 int r= get_vlc2(s, table, bits, max_depth); 904 int len= get_bits_count(s) - pos; 905 int bits2= show>>(24-len); 906 907 print_bin(bits2, len); 908 909 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line); 910 return r; 911} 912static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){ 913 int show= show_bits(s, n); 914 int r= get_xbits(s, n); 915 916 print_bin(show, n); 917 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d xbt @%5d in %s %s:%d\n", show, n, r, get_bits_count(s)-n, file, func, line); 918 return r; 919} 920 921#define get_bits(s, n) get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__) 922#define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__) 923#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__) 924#define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__) 925#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__) 926 927#define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__) 928 929#else //TRACE 930#define tprintf(p, ...) {} 931#endif 932 933static inline int decode012(GetBitContext *gb){ 934 int n; 935 n = get_bits1(gb); 936 if (n == 0) 937 return 0; 938 else 939 return get_bits1(gb) + 1; 940} 941 942static inline int decode210(GetBitContext *gb){ 943 if (get_bits1(gb)) 944 return 0; 945 else 946 return 2 - get_bits1(gb); 947} 948 949#endif /* AVCODEC_BITSTREAM_H */ 950