libavcodec/bitstream.h

   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 bitstream.h
  23  * bitstream api header.
  24  */
  25
  26 #ifndef BITSTREAM_H
  27 #define BITSTREAM_H
  28
  29 #include <stdint.h>
  30 #include <stdlib.h>
  31 #include <assert.h>
  32 #include "common.h"
  33 #include "bswap.h"
  34 #include "log.h"
  35
  36 #if defined(ALT_BITSTREAM_READER_LE) && !defined(ALT_BITSTREAM_READER)
  37 #define ALT_BITSTREAM_READER
  38 #endif
  39
  40 //#define ALT_BITSTREAM_WRITER
  41 //#define ALIGNED_BITSTREAM_WRITER
  42 #if !defined(LIBMPEG2_BITSTREAM_READER) && !defined(A32_BITSTREAM_READER) && !defined(ALT_BITSTREAM_READER)
  43 #   ifdef ARCH_ARMV4L
  44 #       define A32_BITSTREAM_READER
  45 #   else
  46 #define ALT_BITSTREAM_READER
  47 //#define LIBMPEG2_BITSTREAM_READER
  48 //#define A32_BITSTREAM_READER
  49 #   endif
  50 #endif
  51 #define LIBMPEG2_BITSTREAM_READER_HACK //add BERO
  52
  53 extern const uint8_t ff_reverse[256];
  54
  55 #if defined(ARCH_X86)
  56 // avoid +32 for shift optimization (gcc should do that ...)
  57 static 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 }
  64 static 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. */
  79 typedef 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 } PutBitContext;
  89
  90 static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
  91 {
  92     if(buffer_size < 0) {
  93         buffer_size = 0;
  94         buffer = NULL;
  95     }
  96
  97     s->buf = buffer;
  98     s->buf_end = s->buf + buffer_size;
  99 #ifdef ALT_BITSTREAM_WRITER
 100     s->index=0;
 101     ((uint32_t*)(s->buf))[0]=0;
 102 //    memset(buffer, 0, buffer_size);
 103 #else
 104     s->buf_ptr = s->buf;
 105     s->bit_left=32;
 106     s->bit_buf=0;
 107 #endif
 108 }
 109
 110 /* return the number of bits output */
 111 static inline int put_bits_count(PutBitContext *s)
 112 {
 113 #ifdef ALT_BITSTREAM_WRITER
 114     return s->index;
 115 #else
 116     return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
 117 #endif
 118 }
 119
 120 /* pad the end of the output stream with zeros */
 121 static inline void flush_put_bits(PutBitContext *s)
 122 {
 123 #ifdef ALT_BITSTREAM_WRITER
 124     align_put_bits(s);
 125 #else
 126     s->bit_buf<<= s->bit_left;
 127     while (s->bit_left < 32) {
 128         /* XXX: should test end of buffer */
 129         *s->buf_ptr++=s->bit_buf >> 24;
 130         s->bit_buf<<=8;
 131         s->bit_left+=8;
 132     }
 133     s->bit_left=32;
 134     s->bit_buf=0;
 135 #endif
 136 }
 137
 138 void align_put_bits(PutBitContext *s);
 139 void ff_put_string(PutBitContext * pbc, char *s, int put_zero);
 140 void ff_copy_bits(PutBitContext *pb, uint8_t *src, int length);
 141
 142 /* bit input */
 143 /* buffer, buffer_end and size_in_bits must be present and used by every reader */
 144 typedef struct GetBitContext {
 145     const uint8_t *buffer, *buffer_end;
 146 #ifdef ALT_BITSTREAM_READER
 147     int index;
 148 #elif defined LIBMPEG2_BITSTREAM_READER
 149     uint8_t *buffer_ptr;
 150     uint32_t cache;
 151     int bit_count;
 152 #elif defined A32_BITSTREAM_READER
 153     uint32_t *buffer_ptr;
 154     uint32_t cache0;
 155     uint32_t cache1;
 156     int bit_count;
 157 #endif
 158     int size_in_bits;
 159 } GetBitContext;
 160
 161 #define VLC_TYPE int16_t
 162
 163 typedef struct VLC {
 164     int bits;
 165     VLC_TYPE (*table)[2]; ///< code, bits
 166     int table_size, table_allocated;
 167 } VLC;
 168
 169 typedef struct RL_VLC_ELEM {
 170     int16_t level;
 171     int8_t len;
 172     uint8_t run;
 173 } RL_VLC_ELEM;
 174
 175 #if defined(ARCH_SPARC) || defined(ARCH_ARMV4L) || defined(ARCH_MIPS) || defined(ARCH_BFIN)
 176 #define UNALIGNED_STORES_ARE_BAD
 177 #endif
 178
 179 /* used to avoid missaligned exceptions on some archs (alpha, ...) */
 180 #if defined(ARCH_X86)
 181 #    define unaligned16(a) (*(const uint16_t*)(a))
 182 #    define unaligned32(a) (*(const uint32_t*)(a))
 183 #    define unaligned64(a) (*(const uint64_t*)(a))
 184 #else
 185 #    ifdef __GNUC__
 186 #    define unaligned(x)                                \
 187 static inline uint##x##_t unaligned##x(const void *v) { \
 188     struct Unaligned {                                  \
 189         uint##x##_t i;                                  \
 190     } __attribute__((packed));                          \
 191                                                         \
 192     return ((const struct Unaligned *) v)->i;           \
 193 }
 194 #    elif defined(__DECC)
 195 #    define unaligned(x)                                        \
 196 static inline uint##x##_t unaligned##x(const void *v) {         \
 197     return *(const __unaligned uint##x##_t *) v;                \
 198 }
 199 #    else
 200 #    define unaligned(x)                                        \
 201 static inline uint##x##_t unaligned##x(const void *v) {         \
 202     return *(const uint##x##_t *) v;                            \
 203 }
 204 #    endif
 205 unaligned(16)
 206 unaligned(32)
 207 unaligned(64)
 208 #undef unaligned
 209 #endif /* defined(ARCH_X86) */
 210
 211 #ifndef ALT_BITSTREAM_WRITER
 212 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
 213 {
 214     unsigned int bit_buf;
 215     int bit_left;
 216
 217     //    printf("put_bits=%d %x\n", n, value);
 218     assert(n == 32 || value < (1U << n));
 219
 220     bit_buf = s->bit_buf;
 221     bit_left = s->bit_left;
 222
 223     //    printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
 224     /* XXX: optimize */
 225     if (n < bit_left) {
 226         bit_buf = (bit_buf<<n) | value;
 227         bit_left-=n;
 228     } else {
 229         bit_buf<<=bit_left;
 230         bit_buf |= value >> (n - bit_left);
 231 #ifdef UNALIGNED_STORES_ARE_BAD
 232         if (3 & (intptr_t) s->buf_ptr) {
 233             s->buf_ptr[0] = bit_buf >> 24;
 234             s->buf_ptr[1] = bit_buf >> 16;
 235             s->buf_ptr[2] = bit_buf >>  8;
 236             s->buf_ptr[3] = bit_buf      ;
 237         } else
 238 #endif
 239         *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
 240         //printf("bitbuf = %08x\n", bit_buf);
 241         s->buf_ptr+=4;
 242         bit_left+=32 - n;
 243         bit_buf = value;
 244     }
 245
 246     s->bit_buf = bit_buf;
 247     s->bit_left = bit_left;
 248 }
 249 #endif
 250
 251
 252 #ifdef ALT_BITSTREAM_WRITER
 253 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
 254 {
 255 #    ifdef ALIGNED_BITSTREAM_WRITER
 256 #        if defined(ARCH_X86)
 257     asm volatile(
 258         "movl %0, %%ecx                 \n\t"
 259         "xorl %%eax, %%eax              \n\t"
 260         "shrdl %%cl, %1, %%eax          \n\t"
 261         "shrl %%cl, %1                  \n\t"
 262         "movl %0, %%ecx                 \n\t"
 263         "shrl $3, %%ecx                 \n\t"
 264         "andl $0xFFFFFFFC, %%ecx        \n\t"
 265         "bswapl %1                      \n\t"
 266         "orl %1, (%2, %%ecx)            \n\t"
 267         "bswapl %%eax                   \n\t"
 268         "addl %3, %0                    \n\t"
 269         "movl %%eax, 4(%2, %%ecx)       \n\t"
 270         : "=&r" (s->index), "=&r" (value)
 271         : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
 272         : "%eax", "%ecx"
 273     );
 274 #        else
 275     int index= s->index;
 276     uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
 277
 278     value<<= 32-n;
 279
 280     ptr[0] |= be2me_32(value>>(index&31));
 281     ptr[1]  = be2me_32(value<<(32-(index&31)));
 282 //if(n>24) printf("%d %d\n", n, value);
 283     index+= n;
 284     s->index= index;
 285 #        endif
 286 #    else //ALIGNED_BITSTREAM_WRITER
 287 #        if defined(ARCH_X86)
 288     asm volatile(
 289         "movl $7, %%ecx                 \n\t"
 290         "andl %0, %%ecx                 \n\t"
 291         "addl %3, %%ecx                 \n\t"
 292         "negl %%ecx                     \n\t"
 293         "shll %%cl, %1                  \n\t"
 294         "bswapl %1                      \n\t"
 295         "movl %0, %%ecx                 \n\t"
 296         "shrl $3, %%ecx                 \n\t"
 297         "orl %1, (%%ecx, %2)            \n\t"
 298         "addl %3, %0                    \n\t"
 299         "movl $0, 4(%%ecx, %2)          \n\t"
 300         : "=&r" (s->index), "=&r" (value)
 301         : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
 302         : "%ecx"
 303     );
 304 #        else
 305     int index= s->index;
 306     uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
 307
 308     ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
 309     ptr[1] = 0;
 310 //if(n>24) printf("%d %d\n", n, value);
 311     index+= n;
 312     s->index= index;
 313 #        endif
 314 #    endif //!ALIGNED_BITSTREAM_WRITER
 315 }
 316 #endif
 317
 318
 319 static inline uint8_t* pbBufPtr(PutBitContext *s)
 320 {
 321 #ifdef ALT_BITSTREAM_WRITER
 322         return s->buf + (s->index>>3);
 323 #else
 324         return s->buf_ptr;
 325 #endif
 326 }
 327
 328 /**
 329  *
 330  * PutBitContext must be flushed & aligned to a byte boundary before calling this.
 331  */
 332 static inline void skip_put_bytes(PutBitContext *s, int n){
 333         assert((put_bits_count(s)&7)==0);
 334 #ifdef ALT_BITSTREAM_WRITER
 335         FIXME may need some cleaning of the buffer
 336         s->index += n<<3;
 337 #else
 338         assert(s->bit_left==32);
 339         s->buf_ptr += n;
 340 #endif
 341 }
 342
 343 /**
 344  * Skips the given number of bits.
 345  * Must only be used if the actual values in the bitstream do not matter.
 346  */
 347 static inline void skip_put_bits(PutBitContext *s, int n){
 348 #ifdef ALT_BITSTREAM_WRITER
 349     s->index += n;
 350 #else
 351     s->bit_left -= n;
 352     s->buf_ptr-= s->bit_left>>5;
 353     s->bit_left &= 31;
 354 #endif
 355 }
 356
 357 /**
 358  * Changes the end of the buffer.
 359  */
 360 static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
 361     s->buf_end= s->buf + size;
 362 }
 363
 364 /* Bitstream reader API docs:
 365 name
 366     abritary name which is used as prefix for the internal variables
 367
 368 gb
 369     getbitcontext
 370
 371 OPEN_READER(name, gb)
 372     loads gb into local variables
 373
 374 CLOSE_READER(name, gb)
 375     stores local vars in gb
 376
 377 UPDATE_CACHE(name, gb)
 378     refills the internal cache from the bitstream
 379     after this call at least MIN_CACHE_BITS will be available,
 380
 381 GET_CACHE(name, gb)
 382     will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
 383
 384 SHOW_UBITS(name, gb, num)
 385     will return the next num bits
 386
 387 SHOW_SBITS(name, gb, num)
 388     will return the next num bits and do sign extension
 389
 390 SKIP_BITS(name, gb, num)
 391     will skip over the next num bits
 392     note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
 393
 394 SKIP_CACHE(name, gb, num)
 395     will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
 396
 397 SKIP_COUNTER(name, gb, num)
 398     will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
 399
 400 LAST_SKIP_CACHE(name, gb, num)
 401     will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
 402
 403 LAST_SKIP_BITS(name, gb, num)
 404     is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
 405
 406 for examples see get_bits, show_bits, skip_bits, get_vlc
 407 */
 408
 409 static inline int unaligned32_be(const void *v)
 410 {
 411 #ifdef CONFIG_ALIGN
 412         const uint8_t *p=v;
 413         return (((p[0]<<8) | p[1])<<16) | (p[2]<<8) | (p[3]);
 414 #else
 415         return be2me_32( unaligned32(v)); //original
 416 #endif
 417 }
 418
 419 static inline int unaligned32_le(const void *v)
 420 {
 421 #ifdef CONFIG_ALIGN
 422        const uint8_t *p=v;
 423        return (((p[3]<<8) | p[2])<<16) | (p[1]<<8) | (p[0]);
 424 #else
 425        return le2me_32( unaligned32(v)); //original
 426 #endif
 427 }
 428
 429 #ifdef ALT_BITSTREAM_READER
 430 #   define MIN_CACHE_BITS 25
 431
 432 #   define OPEN_READER(name, gb)\
 433         int name##_index= (gb)->index;\
 434         int name##_cache= 0;\
 435
 436 #   define CLOSE_READER(name, gb)\
 437         (gb)->index= name##_index;\
 438
 439 # ifdef ALT_BITSTREAM_READER_LE
 440 #   define UPDATE_CACHE(name, gb)\
 441         name##_cache= unaligned32_le( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
 442
 443 #   define SKIP_CACHE(name, gb, num)\
 444         name##_cache >>= (num);
 445 # else
 446 #   define UPDATE_CACHE(name, gb)\
 447         name##_cache= unaligned32_be( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
 448
 449 #   define SKIP_CACHE(name, gb, num)\
 450         name##_cache <<= (num);
 451 # endif
 452
 453 // FIXME name?
 454 #   define SKIP_COUNTER(name, gb, num)\
 455         name##_index += (num);\
 456
 457 #   define SKIP_BITS(name, gb, num)\
 458         {\
 459             SKIP_CACHE(name, gb, num)\
 460             SKIP_COUNTER(name, gb, num)\
 461         }\
 462
 463 #   define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
 464 #   define LAST_SKIP_CACHE(name, gb, num) ;
 465
 466 # ifdef ALT_BITSTREAM_READER_LE
 467 #   define SHOW_UBITS(name, gb, num)\
 468         ((name##_cache) & (NEG_USR32(0xffffffff,num)))
 469
 470 #   define SHOW_SBITS(name, gb, num)\
 471         NEG_SSR32((name##_cache)<<(32-(num)), num)
 472 # else
 473 #   define SHOW_UBITS(name, gb, num)\
 474         NEG_USR32(name##_cache, num)
 475
 476 #   define SHOW_SBITS(name, gb, num)\
 477         NEG_SSR32(name##_cache, num)
 478 # endif
 479
 480 #   define GET_CACHE(name, gb)\
 481         ((uint32_t)name##_cache)
 482
 483 static inline int get_bits_count(GetBitContext *s){
 484     return s->index;
 485 }
 486
 487 static inline void skip_bits_long(GetBitContext *s, int n){
 488     s->index += n;
 489 }
 490
 491 #elif defined LIBMPEG2_BITSTREAM_READER
 492 //libmpeg2 like reader
 493
 494 #   define MIN_CACHE_BITS 17
 495
 496 #   define OPEN_READER(name, gb)\
 497         int name##_bit_count=(gb)->bit_count;\
 498         int name##_cache= (gb)->cache;\
 499         uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
 500
 501 #   define CLOSE_READER(name, gb)\
 502         (gb)->bit_count= name##_bit_count;\
 503         (gb)->cache= name##_cache;\
 504         (gb)->buffer_ptr= name##_buffer_ptr;\
 505
 506 #ifdef LIBMPEG2_BITSTREAM_READER_HACK
 507
 508 #   define UPDATE_CACHE(name, gb)\
 509     if(name##_bit_count >= 0){\
 510         name##_cache+= (int)be2me_16(*(uint16_t*)name##_buffer_ptr) << name##_bit_count;\
 511         name##_buffer_ptr += 2;\
 512         name##_bit_count-= 16;\
 513     }\
 514
 515 #else
 516
 517 #   define UPDATE_CACHE(name, gb)\
 518     if(name##_bit_count >= 0){\
 519         name##_cache+= ((name##_buffer_ptr[0]<<8) + name##_buffer_ptr[1]) << name##_bit_count;\
 520         name##_buffer_ptr+=2;\
 521         name##_bit_count-= 16;\
 522     }\
 523
 524 #endif
 525
 526 #   define SKIP_CACHE(name, gb, num)\
 527         name##_cache <<= (num);\
 528
 529 #   define SKIP_COUNTER(name, gb, num)\
 530         name##_bit_count += (num);\
 531
 532 #   define SKIP_BITS(name, gb, num)\
 533         {\
 534             SKIP_CACHE(name, gb, num)\
 535             SKIP_COUNTER(name, gb, num)\
 536         }\
 537
 538 #   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
 539 #   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
 540
 541 #   define SHOW_UBITS(name, gb, num)\
 542         NEG_USR32(name##_cache, num)
 543
 544 #   define SHOW_SBITS(name, gb, num)\
 545         NEG_SSR32(name##_cache, num)
 546
 547 #   define GET_CACHE(name, gb)\
 548         ((uint32_t)name##_cache)
 549
 550 static inline int get_bits_count(GetBitContext *s){
 551     return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
 552 }
 553
 554 static inline void skip_bits_long(GetBitContext *s, int n){
 555     OPEN_READER(re, s)
 556     re_bit_count += n;
 557     re_buffer_ptr += 2*(re_bit_count>>4);
 558     re_bit_count &= 15;
 559     re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
 560     UPDATE_CACHE(re, s)
 561     CLOSE_READER(re, s)
 562 }
 563
 564 #elif defined A32_BITSTREAM_READER
 565
 566 #   define MIN_CACHE_BITS 32
 567
 568 #   define OPEN_READER(name, gb)\
 569         int name##_bit_count=(gb)->bit_count;\
 570         uint32_t name##_cache0= (gb)->cache0;\
 571         uint32_t name##_cache1= (gb)->cache1;\
 572         uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
 573
 574 #   define CLOSE_READER(name, gb)\
 575         (gb)->bit_count= name##_bit_count;\
 576         (gb)->cache0= name##_cache0;\
 577         (gb)->cache1= name##_cache1;\
 578         (gb)->buffer_ptr= name##_buffer_ptr;\
 579
 580 #   define UPDATE_CACHE(name, gb)\
 581     if(name##_bit_count > 0){\
 582         const uint32_t next= be2me_32( *name##_buffer_ptr );\
 583         name##_cache0 |= NEG_USR32(next,name##_bit_count);\
 584         name##_cache1 |= next<<name##_bit_count;\
 585         name##_buffer_ptr++;\
 586         name##_bit_count-= 32;\
 587     }\
 588
 589 #if defined(ARCH_X86)
 590 #   define SKIP_CACHE(name, gb, num)\
 591         asm(\
 592             "shldl %2, %1, %0          \n\t"\
 593             "shll %2, %1               \n\t"\
 594             : "+r" (name##_cache0), "+r" (name##_cache1)\
 595             : "Ic" ((uint8_t)(num))\
 596            );
 597 #else
 598 #   define SKIP_CACHE(name, gb, num)\
 599         name##_cache0 <<= (num);\
 600         name##_cache0 |= NEG_USR32(name##_cache1,num);\
 601         name##_cache1 <<= (num);
 602 #endif
 603
 604 #   define SKIP_COUNTER(name, gb, num)\
 605         name##_bit_count += (num);\
 606
 607 #   define SKIP_BITS(name, gb, num)\
 608         {\
 609             SKIP_CACHE(name, gb, num)\
 610             SKIP_COUNTER(name, gb, num)\
 611         }\
 612
 613 #   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
 614 #   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
 615
 616 #   define SHOW_UBITS(name, gb, num)\
 617         NEG_USR32(name##_cache0, num)
 618
 619 #   define SHOW_SBITS(name, gb, num)\
 620         NEG_SSR32(name##_cache0, num)
 621
 622 #   define GET_CACHE(name, gb)\
 623         (name##_cache0)
 624
 625 static inline int get_bits_count(GetBitContext *s){
 626     return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
 627 }
 628
 629 static inline void skip_bits_long(GetBitContext *s, int n){
 630     OPEN_READER(re, s)
 631     re_bit_count += n;
 632     re_buffer_ptr += re_bit_count>>5;
 633     re_bit_count &= 31;
 634     re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
 635     re_cache1 = 0;
 636     UPDATE_CACHE(re, s)
 637     CLOSE_READER(re, s)
 638 }
 639
 640 #endif
 641
 642 /**
 643  * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
 644  * if MSB not set it is negative
 645  * @param n length in bits
 646  * @author BERO
 647  */
 648 static inline int get_xbits(GetBitContext *s, int n){
 649     register int sign;
 650     register int32_t cache;
 651     OPEN_READER(re, s)
 652     UPDATE_CACHE(re, s)
 653     cache = GET_CACHE(re,s);
 654     sign=(~cache)>>31;
 655     LAST_SKIP_BITS(re, s, n)
 656     CLOSE_READER(re, s)
 657     return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
 658 }
 659
 660 static inline int get_sbits(GetBitContext *s, int n){
 661     register int tmp;
 662     OPEN_READER(re, s)
 663     UPDATE_CACHE(re, s)
 664     tmp= SHOW_SBITS(re, s, n);
 665     LAST_SKIP_BITS(re, s, n)
 666     CLOSE_READER(re, s)
 667     return tmp;
 668 }
 669
 670 /**
 671  * reads 1-17 bits.
 672  * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
 673  */
 674 static inline unsigned int get_bits(GetBitContext *s, int n){
 675     register int tmp;
 676     OPEN_READER(re, s)
 677     UPDATE_CACHE(re, s)
 678     tmp= SHOW_UBITS(re, s, n);
 679     LAST_SKIP_BITS(re, s, n)
 680     CLOSE_READER(re, s)
 681     return tmp;
 682 }
 683
 684 /**
 685  * shows 1-17 bits.
 686  * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
 687  */
 688 static inline unsigned int show_bits(GetBitContext *s, int n){
 689     register int tmp;
 690     OPEN_READER(re, s)
 691     UPDATE_CACHE(re, s)
 692     tmp= SHOW_UBITS(re, s, n);
 693 //    CLOSE_READER(re, s)
 694     return tmp;
 695 }
 696
 697 static inline void skip_bits(GetBitContext *s, int n){
 698  //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
 699     OPEN_READER(re, s)
 700     UPDATE_CACHE(re, s)
 701     LAST_SKIP_BITS(re, s, n)
 702     CLOSE_READER(re, s)
 703 }
 704
 705 static inline unsigned int get_bits1(GetBitContext *s){
 706 #ifdef ALT_BITSTREAM_READER
 707     int index= s->index;
 708     uint8_t result= s->buffer[ index>>3 ];
 709 #ifdef ALT_BITSTREAM_READER_LE
 710     result>>= (index&0x07);
 711     result&= 1;
 712 #else
 713     result<<= (index&0x07);
 714     result>>= 8 - 1;
 715 #endif
 716     index++;
 717     s->index= index;
 718
 719     return result;
 720 #else
 721     return get_bits(s, 1);
 722 #endif
 723 }
 724
 725 static inline unsigned int show_bits1(GetBitContext *s){
 726     return show_bits(s, 1);
 727 }
 728
 729 static inline void skip_bits1(GetBitContext *s){
 730     skip_bits(s, 1);
 731 }
 732
 733 /**
 734  * reads 0-32 bits.
 735  */
 736 static inline unsigned int get_bits_long(GetBitContext *s, int n){
 737     if(n<=17) return get_bits(s, n);
 738     else{
 739 #ifdef ALT_BITSTREAM_READER_LE
 740         int ret= get_bits(s, 16);
 741         return ret | (get_bits(s, n-16) << 16);
 742 #else
 743         int ret= get_bits(s, 16) << (n-16);
 744         return ret | get_bits(s, n-16);
 745 #endif
 746     }
 747 }
 748
 749 /**
 750  * shows 0-32 bits.
 751  */
 752 static inline unsigned int show_bits_long(GetBitContext *s, int n){
 753     if(n<=17) return show_bits(s, n);
 754     else{
 755         GetBitContext gb= *s;
 756         int ret= get_bits_long(s, n);
 757         *s= gb;
 758         return ret;
 759     }
 760 }
 761
 762 static inline int check_marker(GetBitContext *s, const char *msg)
 763 {
 764     int bit= get_bits1(s);
 765     if(!bit)
 766         av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
 767
 768     return bit;
 769 }
 770
 771 /**
 772  * init GetBitContext.
 773  * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
 774  * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
 775  * @param bit_size the size of the buffer in bits
 776  */
 777 static inline void init_get_bits(GetBitContext *s,
 778                    const uint8_t *buffer, int bit_size)
 779 {
 780     int buffer_size= (bit_size+7)>>3;
 781     if(buffer_size < 0 || bit_size < 0) {
 782         buffer_size = bit_size = 0;
 783         buffer = NULL;
 784     }
 785
 786     s->buffer= buffer;
 787     s->size_in_bits= bit_size;
 788     s->buffer_end= buffer + buffer_size;
 789 #ifdef ALT_BITSTREAM_READER
 790     s->index=0;
 791 #elif defined LIBMPEG2_BITSTREAM_READER
 792     s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
 793     s->bit_count = 16 + 8*((intptr_t)buffer&1);
 794     skip_bits_long(s, 0);
 795 #elif defined A32_BITSTREAM_READER
 796     s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
 797     s->bit_count = 32 + 8*((intptr_t)buffer&3);
 798     skip_bits_long(s, 0);
 799 #endif
 800 }
 801
 802 static inline void align_get_bits(GetBitContext *s)
 803 {
 804     int n= (-get_bits_count(s)) & 7;
 805     if(n) skip_bits(s, n);
 806 }
 807
 808 #define init_vlc(vlc, nb_bits, nb_codes,\
 809                  bits, bits_wrap, bits_size,\
 810                  codes, codes_wrap, codes_size,\
 811                  flags)\
 812         init_vlc_sparse(vlc, nb_bits, nb_codes,\
 813                  bits, bits_wrap, bits_size,\
 814                  codes, codes_wrap, codes_size,\
 815                  NULL, 0, 0, flags)
 816
 817 int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
 818              const void *bits, int bits_wrap, int bits_size,
 819              const void *codes, int codes_wrap, int codes_size,
 820              const void *symbols, int symbols_wrap, int symbols_size,
 821              int flags);
 822 #define INIT_VLC_USE_STATIC 1
 823 #define INIT_VLC_LE         2
 824 void free_vlc(VLC *vlc);
 825
 826 /**
 827  *
 828  * if the vlc code is invalid and max_depth=1 than no bits will be removed
 829  * if the vlc code is invalid and max_depth>1 than the number of bits removed
 830  * is undefined
 831  */
 832 #define GET_VLC(code, name, gb, table, bits, max_depth)\
 833 {\
 834     int n, index, nb_bits;\
 835 \
 836     index= SHOW_UBITS(name, gb, bits);\
 837     code = table[index][0];\
 838     n    = table[index][1];\
 839 \
 840     if(max_depth > 1 && n < 0){\
 841         LAST_SKIP_BITS(name, gb, bits)\
 842         UPDATE_CACHE(name, gb)\
 843 \
 844         nb_bits = -n;\
 845 \
 846         index= SHOW_UBITS(name, gb, nb_bits) + code;\
 847         code = table[index][0];\
 848         n    = table[index][1];\
 849         if(max_depth > 2 && n < 0){\
 850             LAST_SKIP_BITS(name, gb, nb_bits)\
 851             UPDATE_CACHE(name, gb)\
 852 \
 853             nb_bits = -n;\
 854 \
 855             index= SHOW_UBITS(name, gb, nb_bits) + code;\
 856             code = table[index][0];\
 857             n    = table[index][1];\
 858         }\
 859     }\
 860     SKIP_BITS(name, gb, n)\
 861 }
 862
 863 #define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
 864 {\
 865     int n, index, nb_bits;\
 866 \
 867     index= SHOW_UBITS(name, gb, bits);\
 868     level = table[index].level;\
 869     n     = table[index].len;\
 870 \
 871     if(max_depth > 1 && n < 0){\
 872         SKIP_BITS(name, gb, bits)\
 873         if(need_update){\
 874             UPDATE_CACHE(name, gb)\
 875         }\
 876 \
 877         nb_bits = -n;\
 878 \
 879         index= SHOW_UBITS(name, gb, nb_bits) + level;\
 880         level = table[index].level;\
 881         n     = table[index].len;\
 882     }\
 883     run= table[index].run;\
 884     SKIP_BITS(name, gb, n)\
 885 }
 886
 887
 888 /**
 889  * parses a vlc code, faster then get_vlc()
 890  * @param bits is the number of bits which will be read at once, must be
 891  *             identical to nb_bits in init_vlc()
 892  * @param max_depth is the number of times bits bits must be read to completely
 893  *                  read the longest vlc code
 894  *                  = (max_vlc_length + bits - 1) / bits
 895  */
 896 static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
 897                                   int bits, int max_depth)
 898 {
 899     int code;
 900
 901     OPEN_READER(re, s)
 902     UPDATE_CACHE(re, s)
 903
 904     GET_VLC(code, re, s, table, bits, max_depth)
 905
 906     CLOSE_READER(re, s)
 907     return code;
 908 }
 909
 910 //#define TRACE
 911
 912 #ifdef TRACE
 913 static inline void print_bin(int bits, int n){
 914     int i;
 915
 916     for(i=n-1; i>=0; i--){
 917         av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
 918     }
 919     for(i=n; i<24; i++)
 920         av_log(NULL, AV_LOG_DEBUG, " ");
 921 }
 922
 923 static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
 924     int r= get_bits(s, n);
 925
 926     print_bin(r, n);
 927     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);
 928     return r;
 929 }
 930 static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
 931     int show= show_bits(s, 24);
 932     int pos= get_bits_count(s);
 933     int r= get_vlc2(s, table, bits, max_depth);
 934     int len= get_bits_count(s) - pos;
 935     int bits2= show>>(24-len);
 936
 937     print_bin(bits2, len);
 938
 939     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
 940     return r;
 941 }
 942 static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
 943     int show= show_bits(s, n);
 944     int r= get_xbits(s, n);
 945
 946     print_bin(show, n);
 947     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);
 948     return r;
 949 }
 950
 951 #define get_bits(s, n)  get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 952 #define get_bits1(s)    get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 953 #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 954 #define get_vlc(s, vlc)            get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 955 #define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 956
 957 #define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
 958
 959 #else //TRACE
 960 #define tprintf(p, ...) {}
 961 #endif
 962
 963 static inline int decode012(GetBitContext *gb){
 964     int n;
 965     n = get_bits1(gb);
 966     if (n == 0)
 967         return 0;
 968     else
 969         return get_bits1(gb) + 1;
 970 }
 971
 972 #endif /* BITSTREAM_H */