apps/codecs/libcook/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 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 <string.h>
  33 #include <stdio.h>
  34 #include "libavutil/bswap.h"
  35
  36 /* The following 2 defines are taken from libavutil/intreadwrite.h */
  37 #define AV_RB32(x)  ((((const uint8_t*)(x))[0] << 24) | \
  38                      (((const uint8_t*)(x))[1] << 16) | \
  39                      (((const uint8_t*)(x))[2] <<  8) | \
  40                       ((const uint8_t*)(x))[3])
  41 #define AV_WB32(p, d) do { \
  42                     ((uint8_t*)(p))[3] = (d); \
  43                     ((uint8_t*)(p))[2] = (d)>>8; \
  44                     ((uint8_t*)(p))[1] = (d)>>16; \
  45                     ((uint8_t*)(p))[0] = (d)>>24; } while(0)
  46
  47 #if defined(ALT_BITSTREAM_READER_LE) && !defined(ALT_BITSTREAM_READER)
  48 #   define ALT_BITSTREAM_READER
  49 #endif
  50
  51 //#define ALT_BITSTREAM_WRITER
  52 //#define ALIGNED_BITSTREAM_WRITER
  53 #if !defined(LIBMPEG2_BITSTREAM_READER) && !defined(A32_BITSTREAM_READER) && !defined(ALT_BITSTREAM_READER)
  54 #   if ARCH_ARM
  55 #       define A32_BITSTREAM_READER
  56 #   else
  57 #       define ALT_BITSTREAM_READER
  58 //#define LIBMPEG2_BITSTREAM_READER
  59 //#define A32_BITSTREAM_READER
  60 #   endif
  61 #endif
  62
  63 extern const uint8_t ff_reverse[256];
  64
  65 #if ARCH_X86
  66 // avoid +32 for shift optimization (gcc should do that ...)
  67 static inline  int32_t NEG_SSR32( int32_t a, int8_t s){
  68     __asm__ ("sarl %1, %0\n\t"
  69          : "+r" (a)
  70          : "ic" ((uint8_t)(-s))
  71     );
  72     return a;
  73 }
  74 static inline uint32_t NEG_USR32(uint32_t a, int8_t s){
  75     __asm__ ("shrl %1, %0\n\t"
  76          : "+r" (a)
  77          : "ic" ((uint8_t)(-s))
  78     );
  79     return a;
  80 }
  81 #else
  82 #    define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
  83 #    define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
  84 #endif
  85
  86 /* bit output */
  87
  88 /* buf and buf_end must be present and used by every alternative writer. */
  89 typedef struct PutBitContext {
  90 #ifdef ALT_BITSTREAM_WRITER
  91     uint8_t *buf, *buf_end;
  92     int index;
  93 #else
  94     uint32_t bit_buf;
  95     int bit_left;
  96     uint8_t *buf, *buf_ptr, *buf_end;
  97 #endif
  98     int size_in_bits;
  99 } PutBitContext;
 100
 101 static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
 102 {
 103     if(buffer_size < 0) {
 104         buffer_size = 0;
 105         buffer = NULL;
 106     }
 107
 108     s->size_in_bits= 8*buffer_size;
 109     s->buf = buffer;
 110     s->buf_end = s->buf + buffer_size;
 111 #ifdef ALT_BITSTREAM_WRITER
 112     s->index=0;
 113     ((uint32_t*)(s->buf))[0]=0;
 114 //    memset(buffer, 0, buffer_size);
 115 #else
 116     s->buf_ptr = s->buf;
 117     s->bit_left=32;
 118     s->bit_buf=0;
 119 #endif
 120 }
 121
 122 /* return the number of bits output */
 123 static inline int put_bits_count(PutBitContext *s)
 124 {
 125 #ifdef ALT_BITSTREAM_WRITER
 126     return s->index;
 127 #else
 128     return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
 129 #endif
 130 }
 131
 132 /* pad the end of the output stream with zeros */
 133 static inline void flush_put_bits(PutBitContext *s)
 134 {
 135 #ifdef ALT_BITSTREAM_WRITER
 136     align_put_bits(s);
 137 #else
 138 #ifndef BITSTREAM_WRITER_LE
 139     s->bit_buf<<= s->bit_left;
 140 #endif
 141     while (s->bit_left < 32) {
 142         /* XXX: should test end of buffer */
 143 #ifdef BITSTREAM_WRITER_LE
 144         *s->buf_ptr++=s->bit_buf;
 145         s->bit_buf>>=8;
 146 #else
 147         *s->buf_ptr++=s->bit_buf >> 24;
 148         s->bit_buf<<=8;
 149 #endif
 150         s->bit_left+=8;
 151     }
 152     s->bit_left=32;
 153     s->bit_buf=0;
 154 #endif
 155 }
 156
 157 void align_put_bits(PutBitContext *s);
 158 void ff_put_string(PutBitContext * pbc, const char *s, int put_zero);
 159 void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length);
 160
 161 /* bit input */
 162 /* buffer, buffer_end and size_in_bits must be present and used by every reader */
 163 typedef struct GetBitContext {
 164     const uint8_t *buffer, *buffer_end;
 165 #ifdef ALT_BITSTREAM_READER
 166     int index;
 167 #elif defined LIBMPEG2_BITSTREAM_READER
 168     uint8_t *buffer_ptr;
 169     uint32_t cache;
 170     int bit_count;
 171 #elif defined A32_BITSTREAM_READER
 172     uint32_t *buffer_ptr;
 173     uint32_t cache0;
 174     uint32_t cache1;
 175     int bit_count;
 176 #endif
 177     int size_in_bits;
 178 } GetBitContext;
 179
 180 #define VLC_TYPE int16_t
 181
 182 typedef struct VLC {
 183     int bits;
 184     VLC_TYPE (*table)[2]; ///< code, bits
 185     int table_size, table_allocated;
 186 } VLC;
 187
 188 typedef struct RL_VLC_ELEM {
 189     int16_t level;
 190     int8_t len;
 191     uint8_t run;
 192 } RL_VLC_ELEM;
 193
 194 #ifndef ALT_BITSTREAM_WRITER
 195 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
 196 {
 197     unsigned int bit_buf;
 198     int bit_left;
 199
 200     //    printf("put_bits=%d %x\n", n, value);
 201     assert(n == 32 || value < (1U << n));
 202
 203     bit_buf = s->bit_buf;
 204     bit_left = s->bit_left;
 205
 206     //    printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
 207     /* XXX: optimize */
 208 #ifdef BITSTREAM_WRITER_LE
 209     bit_buf |= value << (32 - bit_left);
 210     if (n >= bit_left) {
 211 #if !HAVE_FAST_UNALIGNED
 212         if (3 & (intptr_t) s->buf_ptr) {
 213             AV_WL32(s->buf_ptr, bit_buf);
 214         } else
 215 #endif
 216         *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
 217         s->buf_ptr+=4;
 218         bit_buf = (bit_left==32)?0:value >> bit_left;
 219         bit_left+=32;
 220     }
 221     bit_left-=n;
 222 #else
 223     if (n < bit_left) {
 224         bit_buf = (bit_buf<<n) | value;
 225         bit_left-=n;
 226     } else {
 227         bit_buf<<=bit_left;
 228         bit_buf |= value >> (n - bit_left);
 229 #if !HAVE_FAST_UNALIGNED
 230         if (3 & (intptr_t) s->buf_ptr) {
 231             AV_WB32(s->buf_ptr, bit_buf);
 232         } else
 233 #endif
 234         *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
 235         //printf("bitbuf = %08x\n", bit_buf);
 236         s->buf_ptr+=4;
 237         bit_left+=32 - n;
 238         bit_buf = value;
 239     }
 240 #endif
 241
 242     s->bit_buf = bit_buf;
 243     s->bit_left = bit_left;
 244 }
 245 #endif
 246
 247
 248 #ifdef ALT_BITSTREAM_WRITER
 249 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
 250 {
 251 #    ifdef ALIGNED_BITSTREAM_WRITER
 252 #        if ARCH_X86
 253     __asm__ volatile(
 254         "movl %0, %%ecx                 \n\t"
 255         "xorl %%eax, %%eax              \n\t"
 256         "shrdl %%cl, %1, %%eax          \n\t"
 257         "shrl %%cl, %1                  \n\t"
 258         "movl %0, %%ecx                 \n\t"
 259         "shrl $3, %%ecx                 \n\t"
 260         "andl $0xFFFFFFFC, %%ecx        \n\t"
 261         "bswapl %1                      \n\t"
 262         "orl %1, (%2, %%ecx)            \n\t"
 263         "bswapl %%eax                   \n\t"
 264         "addl %3, %0                    \n\t"
 265         "movl %%eax, 4(%2, %%ecx)       \n\t"
 266         : "=&r" (s->index), "=&r" (value)
 267         : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
 268         : "%eax", "%ecx"
 269     );
 270 #        else
 271     int index= s->index;
 272     uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
 273
 274     value<<= 32-n;
 275
 276     ptr[0] |= be2me_32(value>>(index&31));
 277     ptr[1]  = be2me_32(value<<(32-(index&31)));
 278 //if(n>24) printf("%d %d\n", n, value);
 279     index+= n;
 280     s->index= index;
 281 #        endif
 282 #    else //ALIGNED_BITSTREAM_WRITER
 283 #        if ARCH_X86
 284     __asm__ volatile(
 285         "movl $7, %%ecx                 \n\t"
 286         "andl %0, %%ecx                 \n\t"
 287         "addl %3, %%ecx                 \n\t"
 288         "negl %%ecx                     \n\t"
 289         "shll %%cl, %1                  \n\t"
 290         "bswapl %1                      \n\t"
 291         "movl %0, %%ecx                 \n\t"
 292         "shrl $3, %%ecx                 \n\t"
 293         "orl %1, (%%ecx, %2)            \n\t"
 294         "addl %3, %0                    \n\t"
 295         "movl $0, 4(%%ecx, %2)          \n\t"
 296         : "=&r" (s->index), "=&r" (value)
 297         : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
 298         : "%ecx"
 299     );
 300 #        else
 301     int index= s->index;
 302     uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
 303
 304     ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
 305     ptr[1] = 0;
 306 //if(n>24) printf("%d %d\n", n, value);
 307     index+= n;
 308     s->index= index;
 309 #        endif
 310 #    endif //!ALIGNED_BITSTREAM_WRITER
 311 }
 312 #endif
 313
 314 static inline void put_sbits(PutBitContext *pb, int bits, int32_t val)
 315 {
 316     assert(bits >= 0 && bits <= 31);
 317
 318     put_bits(pb, bits, val & ((1<<bits)-1));
 319 }
 320
 321
 322 static inline uint8_t* pbBufPtr(PutBitContext *s)
 323 {
 324 #ifdef ALT_BITSTREAM_WRITER
 325         return s->buf + (s->index>>3);
 326 #else
 327         return s->buf_ptr;
 328 #endif
 329 }
 330
 331 /**
 332  *
 333  * PutBitContext must be flushed & aligned to a byte boundary before calling this.
 334  */
 335 static inline void skip_put_bytes(PutBitContext *s, int n){
 336         assert((put_bits_count(s)&7)==0);
 337 #ifdef ALT_BITSTREAM_WRITER
 338         FIXME may need some cleaning of the buffer
 339         s->index += n<<3;
 340 #else
 341         assert(s->bit_left==32);
 342         s->buf_ptr += n;
 343 #endif
 344 }
 345
 346 /**
 347  * Skips the given number of bits.
 348  * Must only be used if the actual values in the bitstream do not matter.
 349  */
 350 static inline void skip_put_bits(PutBitContext *s, int n){
 351 #ifdef ALT_BITSTREAM_WRITER
 352     s->index += n;
 353 #else
 354     s->bit_left -= n;
 355     s->buf_ptr-= s->bit_left>>5;
 356     s->bit_left &= 31;
 357 #endif
 358 }
 359
 360 /**
 361  * Changes the end of the buffer.
 362  */
 363 static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
 364     s->buf_end= s->buf + size;
 365 }
 366
 367 /* Bitstream reader API docs:
 368 name
 369     arbitrary name which is used as prefix for the internal variables
 370
 371 gb
 372     getbitcontext
 373
 374 OPEN_READER(name, gb)
 375     loads gb into local variables
 376
 377 CLOSE_READER(name, gb)
 378     stores local vars in gb
 379
 380 UPDATE_CACHE(name, gb)
 381     refills the internal cache from the bitstream
 382     after this call at least MIN_CACHE_BITS will be available,
 383
 384 GET_CACHE(name, gb)
 385     will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
 386
 387 SHOW_UBITS(name, gb, num)
 388     will return the next num bits
 389
 390 SHOW_SBITS(name, gb, num)
 391     will return the next num bits and do sign extension
 392
 393 SKIP_BITS(name, gb, num)
 394     will skip over the next num bits
 395     note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
 396
 397 SKIP_CACHE(name, gb, num)
 398     will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
 399
 400 SKIP_COUNTER(name, gb, num)
 401     will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
 402
 403 LAST_SKIP_CACHE(name, gb, num)
 404     will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
 405
 406 LAST_SKIP_BITS(name, gb, num)
 407     is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
 408
 409 for examples see get_bits, show_bits, skip_bits, get_vlc
 410 */
 411
 412 #ifdef ALT_BITSTREAM_READER
 413 #   define MIN_CACHE_BITS 25
 414
 415 #   define OPEN_READER(name, gb)\
 416         int name##_index= (gb)->index;\
 417         int name##_cache= 0;\
 418
 419 #   define CLOSE_READER(name, gb)\
 420         (gb)->index= name##_index;\
 421
 422 # ifdef ALT_BITSTREAM_READER_LE
 423 #   define UPDATE_CACHE(name, gb)\
 424         name##_cache= AV_RL32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
 425
 426 #   define SKIP_CACHE(name, gb, num)\
 427         name##_cache >>= (num);
 428 # else
 429 #   define UPDATE_CACHE(name, gb)\
 430         name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
 431
 432 #   define SKIP_CACHE(name, gb, num)\
 433         name##_cache <<= (num);
 434 # endif
 435
 436 // FIXME name?
 437 #   define SKIP_COUNTER(name, gb, num)\
 438         name##_index += (num);\
 439
 440 #   define SKIP_BITS(name, gb, num)\
 441         {\
 442             SKIP_CACHE(name, gb, num)\
 443             SKIP_COUNTER(name, gb, num)\
 444         }\
 445
 446 #   define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
 447 #   define LAST_SKIP_CACHE(name, gb, num) ;
 448
 449 # ifdef ALT_BITSTREAM_READER_LE
 450 #   define SHOW_UBITS(name, gb, num)\
 451         ((name##_cache) & (NEG_USR32(0xffffffff,num)))
 452
 453 #   define SHOW_SBITS(name, gb, num)\
 454         NEG_SSR32((name##_cache)<<(32-(num)), num)
 455 # else
 456 #   define SHOW_UBITS(name, gb, num)\
 457         NEG_USR32(name##_cache, num)
 458
 459 #   define SHOW_SBITS(name, gb, num)\
 460         NEG_SSR32(name##_cache, num)
 461 # endif
 462
 463 #   define GET_CACHE(name, gb)\
 464         ((uint32_t)name##_cache)
 465
 466 static inline int get_bits_count(GetBitContext *s){
 467     return s->index;
 468 }
 469
 470 static inline void skip_bits_long(GetBitContext *s, int n){
 471     s->index += n;
 472 }
 473
 474 #elif defined LIBMPEG2_BITSTREAM_READER
 475 //libmpeg2 like reader
 476
 477 #   define MIN_CACHE_BITS 17
 478
 479 #   define OPEN_READER(name, gb)\
 480         int name##_bit_count=(gb)->bit_count;\
 481         int name##_cache= (gb)->cache;\
 482         uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
 483
 484 #   define CLOSE_READER(name, gb)\
 485         (gb)->bit_count= name##_bit_count;\
 486         (gb)->cache= name##_cache;\
 487         (gb)->buffer_ptr= name##_buffer_ptr;\
 488
 489 #   define UPDATE_CACHE(name, gb)\
 490     if(name##_bit_count >= 0){\
 491         name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count; \
 492         name##_buffer_ptr+=2;\
 493         name##_bit_count-= 16;\
 494     }\
 495
 496 #   define SKIP_CACHE(name, gb, num)\
 497         name##_cache <<= (num);\
 498
 499 #   define SKIP_COUNTER(name, gb, num)\
 500         name##_bit_count += (num);\
 501
 502 #   define SKIP_BITS(name, gb, num)\
 503         {\
 504             SKIP_CACHE(name, gb, num)\
 505             SKIP_COUNTER(name, gb, num)\
 506         }\
 507
 508 #   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
 509 #   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
 510
 511 #   define SHOW_UBITS(name, gb, num)\
 512         NEG_USR32(name##_cache, num)
 513
 514 #   define SHOW_SBITS(name, gb, num)\
 515         NEG_SSR32(name##_cache, num)
 516
 517 #   define GET_CACHE(name, gb)\
 518         ((uint32_t)name##_cache)
 519
 520 static inline int get_bits_count(GetBitContext *s){
 521     return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
 522 }
 523
 524 static inline void skip_bits_long(GetBitContext *s, int n){
 525     OPEN_READER(re, s)
 526     re_bit_count += n;
 527     re_buffer_ptr += 2*(re_bit_count>>4);
 528     re_bit_count &= 15;
 529     re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
 530     UPDATE_CACHE(re, s)
 531     CLOSE_READER(re, s)
 532 }
 533
 534 #elif defined A32_BITSTREAM_READER
 535
 536 #   define MIN_CACHE_BITS 32
 537
 538 #   define OPEN_READER(name, gb)\
 539         int name##_bit_count=(gb)->bit_count;\
 540         uint32_t name##_cache0= (gb)->cache0;\
 541         uint32_t name##_cache1= (gb)->cache1;\
 542         uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
 543
 544 #   define CLOSE_READER(name, gb)\
 545         (gb)->bit_count= name##_bit_count;\
 546         (gb)->cache0= name##_cache0;\
 547         (gb)->cache1= name##_cache1;\
 548         (gb)->buffer_ptr= name##_buffer_ptr;\
 549
 550 #   define UPDATE_CACHE(name, gb)\
 551     if(name##_bit_count > 0){\
 552         const uint32_t next= be2me_32( *name##_buffer_ptr );\
 553         name##_cache0 |= NEG_USR32(next,name##_bit_count);\
 554         name##_cache1 |= next<<name##_bit_count;\
 555         name##_buffer_ptr++;\
 556         name##_bit_count-= 32;\
 557     }\
 558
 559 #if ARCH_X86
 560 #   define SKIP_CACHE(name, gb, num)\
 561         __asm__(\
 562             "shldl %2, %1, %0          \n\t"\
 563             "shll %2, %1               \n\t"\
 564             : "+r" (name##_cache0), "+r" (name##_cache1)\
 565             : "Ic" ((uint8_t)(num))\
 566            );
 567 #else
 568 #   define SKIP_CACHE(name, gb, num)\
 569         name##_cache0 <<= (num);\
 570         name##_cache0 |= NEG_USR32(name##_cache1,num);\
 571         name##_cache1 <<= (num);
 572 #endif
 573
 574 #   define SKIP_COUNTER(name, gb, num)\
 575         name##_bit_count += (num);\
 576
 577 #   define SKIP_BITS(name, gb, num)\
 578         {\
 579             SKIP_CACHE(name, gb, num)\
 580             SKIP_COUNTER(name, gb, num)\
 581         }\
 582
 583 #   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
 584 #   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
 585
 586 #   define SHOW_UBITS(name, gb, num)\
 587         NEG_USR32(name##_cache0, num)
 588
 589 #   define SHOW_SBITS(name, gb, num)\
 590         NEG_SSR32(name##_cache0, num)
 591
 592 #   define GET_CACHE(name, gb)\
 593         (name##_cache0)
 594
 595 static inline int get_bits_count(GetBitContext *s){
 596     return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
 597 }
 598
 599 static inline void skip_bits_long(GetBitContext *s, int n){
 600     OPEN_READER(re, s)
 601     re_bit_count += n;
 602     re_buffer_ptr += re_bit_count>>5;
 603     re_bit_count &= 31;
 604     re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
 605     re_cache1 = 0;
 606     UPDATE_CACHE(re, s)
 607     CLOSE_READER(re, s)
 608 }
 609
 610 #endif
 611
 612 /**
 613  * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
 614  * if MSB not set it is negative
 615  * @param n length in bits
 616  * @author BERO
 617  */
 618 static inline int get_xbits(GetBitContext *s, int n){
 619     register int sign;
 620     register int32_t cache;
 621     OPEN_READER(re, s)
 622     UPDATE_CACHE(re, s)
 623     cache = GET_CACHE(re,s);
 624     sign=(~cache)>>31;
 625     LAST_SKIP_BITS(re, s, n)
 626     CLOSE_READER(re, s)
 627     return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
 628 }
 629
 630 static inline int get_sbits(GetBitContext *s, int n){
 631     register int tmp;
 632     OPEN_READER(re, s)
 633     UPDATE_CACHE(re, s)
 634     tmp= SHOW_SBITS(re, s, n);
 635     LAST_SKIP_BITS(re, s, n)
 636     CLOSE_READER(re, s)
 637     return tmp;
 638 }
 639
 640 /**
 641  * reads 1-17 bits.
 642  * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
 643  */
 644 static inline unsigned int get_bits(GetBitContext *s, int n){
 645     register int tmp;
 646     OPEN_READER(re, s)
 647     UPDATE_CACHE(re, s)
 648     tmp= SHOW_UBITS(re, s, n);
 649     LAST_SKIP_BITS(re, s, n)
 650     CLOSE_READER(re, s)
 651     return tmp;
 652 }
 653
 654 /**
 655  * shows 1-17 bits.
 656  * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
 657  */
 658 static inline unsigned int show_bits(GetBitContext *s, int n){
 659     register int tmp;
 660     OPEN_READER(re, s)
 661     UPDATE_CACHE(re, s)
 662     tmp= SHOW_UBITS(re, s, n);
 663 //    CLOSE_READER(re, s)
 664     return tmp;
 665 }
 666
 667 static inline void skip_bits(GetBitContext *s, int n){
 668  //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
 669     OPEN_READER(re, s)
 670     UPDATE_CACHE(re, s)
 671     LAST_SKIP_BITS(re, s, n)
 672     CLOSE_READER(re, s)
 673 }
 674
 675 static inline unsigned int get_bits1(GetBitContext *s){
 676 #ifdef ALT_BITSTREAM_READER
 677     int index= s->index;
 678     uint8_t result= s->buffer[ index>>3 ];
 679 #ifdef ALT_BITSTREAM_READER_LE
 680     result>>= (index&0x07);
 681     result&= 1;
 682 #else
 683     result<<= (index&0x07);
 684     result>>= 8 - 1;
 685 #endif
 686     index++;
 687     s->index= index;
 688
 689     return result;
 690 #else
 691     return get_bits(s, 1);
 692 #endif
 693 }
 694
 695 static inline unsigned int show_bits1(GetBitContext *s){
 696     return show_bits(s, 1);
 697 }
 698
 699 static inline void skip_bits1(GetBitContext *s){
 700     skip_bits(s, 1);
 701 }
 702
 703 /**
 704  * reads 0-32 bits.
 705  */
 706 static inline unsigned int get_bits_long(GetBitContext *s, int n){
 707     if(n<=17) return get_bits(s, n);
 708     else{
 709 #ifdef ALT_BITSTREAM_READER_LE
 710         int ret= get_bits(s, 16);
 711         return ret | (get_bits(s, n-16) << 16);
 712 #else
 713         int ret= get_bits(s, 16) << (n-16);
 714         return ret | get_bits(s, n-16);
 715 #endif
 716     }
 717 }
 718
 719 #if 0
 720 /**
 721  * reads 0-32 bits as a signed integer.
 722  */
 723 static inline int get_sbits_long(GetBitContext *s, int n) {
 724     return sign_extend(get_bits_long(s, n), n);
 725 }
 726 #endif
 727
 728 /**
 729  * shows 0-32 bits.
 730  */
 731 static inline unsigned int show_bits_long(GetBitContext *s, int n){
 732     if(n<=17) return show_bits(s, n);
 733     else{
 734         GetBitContext gb= *s;
 735         return get_bits_long(&gb, n);
 736     }
 737 }
 738
 739 static inline int check_marker(GetBitContext *s, const char *msg)
 740 {
 741     int bit= get_bits1(s);
 742     if(!bit)
 743         printf("Marker bit missing %s\n", msg);
 744
 745     return bit;
 746 }
 747
 748 /**
 749  * init GetBitContext.
 750  * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
 751  * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
 752  * @param bit_size the size of the buffer in bits
 753  */
 754 static inline void init_get_bits(GetBitContext *s,
 755                    const uint8_t *buffer, int bit_size)
 756 {
 757     int buffer_size= (bit_size+7)>>3;
 758     if(buffer_size < 0 || bit_size < 0) {
 759         buffer_size = bit_size = 0;
 760         buffer = NULL;
 761     }
 762
 763     s->buffer= buffer;
 764     s->size_in_bits= bit_size;
 765     s->buffer_end= buffer + buffer_size;
 766 #ifdef ALT_BITSTREAM_READER
 767     s->index=0;
 768 #elif defined LIBMPEG2_BITSTREAM_READER
 769     s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
 770     s->bit_count = 16 + 8*((intptr_t)buffer&1);
 771     skip_bits_long(s, 0);
 772 #elif defined A32_BITSTREAM_READER
 773     s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
 774     s->bit_count = 32 + 8*((intptr_t)buffer&3);
 775     skip_bits_long(s, 0);
 776 #endif
 777 }
 778
 779 static inline void align_get_bits(GetBitContext *s)
 780 {
 781     int n= (-get_bits_count(s)) & 7;
 782     if(n) skip_bits(s, n);
 783 }
 784
 785 #define init_vlc(vlc, nb_bits, nb_codes,\
 786                  bits, bits_wrap, bits_size,\
 787                  codes, codes_wrap, codes_size,\
 788                  flags)\
 789         init_vlc_sparse(vlc, nb_bits, nb_codes,\
 790                  bits, bits_wrap, bits_size,\
 791                  codes, codes_wrap, codes_size,\
 792                  NULL, 0, 0, flags)
 793
 794 int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
 795              const void *bits, int bits_wrap, int bits_size,
 796              const void *codes, int codes_wrap, int codes_size,
 797              const void *symbols, int symbols_wrap, int symbols_size,
 798              int flags);
 799 #define INIT_VLC_USE_STATIC 1 ///< VERY strongly deprecated and forbidden
 800 #define INIT_VLC_LE         2
 801 #define INIT_VLC_USE_NEW_STATIC 4
 802 void free_vlc(VLC *vlc);
 803
 804 #define INIT_VLC_STATIC(vlc, bits, a,b,c,d,e,f,g, static_size)\
 805 {\
 806     static VLC_TYPE table[static_size][2];\
 807     (vlc)->table= table;\
 808     (vlc)->table_allocated= static_size;\
 809     init_vlc(vlc, bits, a,b,c,d,e,f,g, INIT_VLC_USE_NEW_STATIC);\
 810 }
 811
 812
 813 /**
 814  *
 815  * if the vlc code is invalid and max_depth=1 than no bits will be removed
 816  * if the vlc code is invalid and max_depth>1 than the number of bits removed
 817  * is undefined
 818  */
 819 #define GET_VLC(code, name, gb, table, bits, max_depth)\
 820 {\
 821     int n, index, nb_bits;\
 822 \
 823     index= SHOW_UBITS(name, gb, bits);\
 824     code = table[index][0];\
 825     n    = table[index][1];\
 826 \
 827     if(max_depth > 1 && n < 0){\
 828         LAST_SKIP_BITS(name, gb, bits)\
 829         UPDATE_CACHE(name, gb)\
 830 \
 831         nb_bits = -n;\
 832 \
 833         index= SHOW_UBITS(name, gb, nb_bits) + code;\
 834         code = table[index][0];\
 835         n    = table[index][1];\
 836         if(max_depth > 2 && n < 0){\
 837             LAST_SKIP_BITS(name, gb, nb_bits)\
 838             UPDATE_CACHE(name, gb)\
 839 \
 840             nb_bits = -n;\
 841 \
 842             index= SHOW_UBITS(name, gb, nb_bits) + code;\
 843             code = table[index][0];\
 844             n    = table[index][1];\
 845         }\
 846     }\
 847     SKIP_BITS(name, gb, n)\
 848 }
 849
 850 #define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
 851 {\
 852     int n, index, nb_bits;\
 853 \
 854     index= SHOW_UBITS(name, gb, bits);\
 855     level = table[index].level;\
 856     n     = table[index].len;\
 857 \
 858     if(max_depth > 1 && n < 0){\
 859         SKIP_BITS(name, gb, bits)\
 860         if(need_update){\
 861             UPDATE_CACHE(name, gb)\
 862         }\
 863 \
 864         nb_bits = -n;\
 865 \
 866         index= SHOW_UBITS(name, gb, nb_bits) + level;\
 867         level = table[index].level;\
 868         n     = table[index].len;\
 869     }\
 870     run= table[index].run;\
 871     SKIP_BITS(name, gb, n)\
 872 }
 873
 874
 875 /**
 876  * parses a vlc code, faster then get_vlc()
 877  * @param bits is the number of bits which will be read at once, must be
 878  *             identical to nb_bits in init_vlc()
 879  * @param max_depth is the number of times bits bits must be read to completely
 880  *                  read the longest vlc code
 881  *                  = (max_vlc_length + bits - 1) / bits
 882  */
 883 static inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
 884                                   int bits, int max_depth)
 885 {
 886     int code;
 887
 888     OPEN_READER(re, s)
 889     UPDATE_CACHE(re, s)
 890
 891     GET_VLC(code, re, s, table, bits, max_depth)
 892
 893     CLOSE_READER(re, s)
 894     return code;
 895 }
 896
 897 //#define TRACE
 898
 899 #ifdef TRACE
 900 static inline void print_bin(int bits, int n){
 901     int i;
 902
 903     for(i=n-1; i>=0; i--){
 904         printf("%d", (bits>>i)&1);
 905     }
 906     for(i=n; i<24; i++)
 907         printf(" ");
 908 }
 909
 910 static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
 911     int r= get_bits(s, n);
 912
 913     print_bin(r, n);
 914     printf("%5d %2d %3d bit @%5d in %s %s:%d\n", r, n, r, get_bits_count(s)-n, file, func, line);
 915     return r;
 916 }
 917 static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
 918     int show= show_bits(s, 24);
 919     int pos= get_bits_count(s);
 920     int r= get_vlc2(s, table, bits, max_depth);
 921     int len= get_bits_count(s) - pos;
 922     int bits2= show>>(24-len);
 923
 924     print_bin(bits2, len);
 925
 926     printf("%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
 927     return r;
 928 }
 929 static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
 930     int show= show_bits(s, n);
 931     int r= get_xbits(s, n);
 932
 933     print_bin(show, n);
 934     printf("%5d %2d %3d xbt @%5d in %s %s:%d\n", show, n, r, get_bits_count(s)-n, file, func, line);
 935     return r;
 936 }
 937
 938 #define get_bits(s, n)  get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 939 #define get_bits1(s)    get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 940 #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 941 #define get_vlc(s, vlc)            get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 942 #define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 943
 944 #define tprintf(p, ...) printf
 945
 946 #else //TRACE
 947 #define tprintf(p, ...) {}
 948 #endif
 949
 950 static inline int decode012(GetBitContext *gb){
 951     int n;
 952     n = get_bits1(gb);
 953     if (n == 0)
 954         return 0;
 955     else
 956         return get_bits1(gb) + 1;
 957 }
 958
 959 static inline int decode210(GetBitContext *gb){
 960     if (get_bits1(gb))
 961         return 0;
 962     else
 963         return 2 - get_bits1(gb);
 964 }
 965
 966 #endif /* AVCODEC_BITSTREAM_H */