195bcc7a18369ca5f300752ad6df9c392f8d43c4
[libav.git] / libavcodec / bitstream.h
1 /**
2 * @file bitstream.h
3 * bitstream api header.
4 */
5
6 #ifndef BITSTREAM_H
7 #define BITSTREAM_H
8
9 //#define ALT_BITSTREAM_WRITER
10 //#define ALIGNED_BITSTREAM_WRITER
11
12 #define ALT_BITSTREAM_READER
13 //#define LIBMPEG2_BITSTREAM_READER
14 //#define A32_BITSTREAM_READER
15 #define LIBMPEG2_BITSTREAM_READER_HACK //add BERO
16
17 extern const uint8_t ff_reverse[256];
18
19 #if defined(ARCH_X86) || defined(ARCH_X86_64)
20 // avoid +32 for shift optimization (gcc should do that ...)
21 static inline int32_t NEG_SSR32( int32_t a, int8_t s){
22 asm ("sarl %1, %0\n\t"
23 : "+r" (a)
24 : "ic" ((uint8_t)(-s))
25 );
26 return a;
27 }
28 static inline uint32_t NEG_USR32(uint32_t a, int8_t s){
29 asm ("shrl %1, %0\n\t"
30 : "+r" (a)
31 : "ic" ((uint8_t)(-s))
32 );
33 return a;
34 }
35 #else
36 # define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
37 # define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
38 #endif
39
40 /* bit output */
41
42 /* buf and buf_end must be present and used by every alternative writer. */
43 typedef struct PutBitContext {
44 #ifdef ALT_BITSTREAM_WRITER
45 uint8_t *buf, *buf_end;
46 int index;
47 #else
48 uint32_t bit_buf;
49 int bit_left;
50 uint8_t *buf, *buf_ptr, *buf_end;
51 #endif
52 } PutBitContext;
53
54 static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
55 {
56 if(buffer_size < 0) {
57 buffer_size = 0;
58 buffer = NULL;
59 }
60
61 s->buf = buffer;
62 s->buf_end = s->buf + buffer_size;
63 #ifdef ALT_BITSTREAM_WRITER
64 s->index=0;
65 ((uint32_t*)(s->buf))[0]=0;
66 // memset(buffer, 0, buffer_size);
67 #else
68 s->buf_ptr = s->buf;
69 s->bit_left=32;
70 s->bit_buf=0;
71 #endif
72 }
73
74 /* return the number of bits output */
75 static inline int put_bits_count(PutBitContext *s)
76 {
77 #ifdef ALT_BITSTREAM_WRITER
78 return s->index;
79 #else
80 return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
81 #endif
82 }
83
84 /* pad the end of the output stream with zeros */
85 static inline void flush_put_bits(PutBitContext *s)
86 {
87 #ifdef ALT_BITSTREAM_WRITER
88 align_put_bits(s);
89 #else
90 s->bit_buf<<= s->bit_left;
91 while (s->bit_left < 32) {
92 /* XXX: should test end of buffer */
93 *s->buf_ptr++=s->bit_buf >> 24;
94 s->bit_buf<<=8;
95 s->bit_left+=8;
96 }
97 s->bit_left=32;
98 s->bit_buf=0;
99 #endif
100 }
101
102 void align_put_bits(PutBitContext *s);
103 void ff_put_string(PutBitContext * pbc, char *s, int put_zero);
104
105 /* bit input */
106 /* buffer, buffer_end and size_in_bits must be present and used by every reader */
107 typedef struct GetBitContext {
108 const uint8_t *buffer, *buffer_end;
109 #ifdef ALT_BITSTREAM_READER
110 int index;
111 #elif defined LIBMPEG2_BITSTREAM_READER
112 uint8_t *buffer_ptr;
113 uint32_t cache;
114 int bit_count;
115 #elif defined A32_BITSTREAM_READER
116 uint32_t *buffer_ptr;
117 uint32_t cache0;
118 uint32_t cache1;
119 int bit_count;
120 #endif
121 int size_in_bits;
122 } GetBitContext;
123
124 #define VLC_TYPE int16_t
125
126 typedef struct VLC {
127 int bits;
128 VLC_TYPE (*table)[2]; ///< code, bits
129 int table_size, table_allocated;
130 } VLC;
131
132 typedef struct RL_VLC_ELEM {
133 int16_t level;
134 int8_t len;
135 uint8_t run;
136 } RL_VLC_ELEM;
137
138 #if defined(ARCH_SPARC) || defined(ARCH_ARMV4L)
139 #define UNALIGNED_STORES_ARE_BAD
140 #endif
141
142 /* used to avoid missaligned exceptions on some archs (alpha, ...) */
143 #if defined(ARCH_X86) || defined(ARCH_X86_64)
144 # define unaligned16(a) (*(const uint16_t*)(a))
145 # define unaligned32(a) (*(const uint32_t*)(a))
146 # define unaligned64(a) (*(const uint64_t*)(a))
147 #else
148 # ifdef __GNUC__
149 # define unaligned(x) \
150 static inline uint##x##_t unaligned##x(const void *v) { \
151 struct Unaligned { \
152 uint##x##_t i; \
153 } __attribute__((packed)); \
154 \
155 return ((const struct Unaligned *) v)->i; \
156 }
157 # elif defined(__DECC)
158 # define unaligned(x) \
159 static inline uint##x##_t unaligned##x##(const void *v) { \
160 return *(const __unaligned uint##x##_t *) v; \
161 }
162 # else
163 # define unaligned(x) \
164 static inline uint##x##_t unaligned##x##(const void *v) { \
165 return *(const uint##x##_t *) v; \
166 }
167 # endif
168 unaligned(16)
169 unaligned(32)
170 unaligned(64)
171 #undef unaligned
172 #endif //!ARCH_X86
173
174 #ifndef ALT_BITSTREAM_WRITER
175 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
176 {
177 unsigned int bit_buf;
178 int bit_left;
179
180 #ifdef STATS
181 st_out_bit_counts[st_current_index] += n;
182 #endif
183 // printf("put_bits=%d %x\n", n, value);
184 assert(n == 32 || value < (1U << n));
185
186 bit_buf = s->bit_buf;
187 bit_left = s->bit_left;
188
189 // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
190 /* XXX: optimize */
191 if (n < bit_left) {
192 bit_buf = (bit_buf<<n) | value;
193 bit_left-=n;
194 } else {
195 bit_buf<<=bit_left;
196 bit_buf |= value >> (n - bit_left);
197 #ifdef UNALIGNED_STORES_ARE_BAD
198 if (3 & (intptr_t) s->buf_ptr) {
199 s->buf_ptr[0] = bit_buf >> 24;
200 s->buf_ptr[1] = bit_buf >> 16;
201 s->buf_ptr[2] = bit_buf >> 8;
202 s->buf_ptr[3] = bit_buf ;
203 } else
204 #endif
205 *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
206 //printf("bitbuf = %08x\n", bit_buf);
207 s->buf_ptr+=4;
208 bit_left+=32 - n;
209 bit_buf = value;
210 }
211
212 s->bit_buf = bit_buf;
213 s->bit_left = bit_left;
214 }
215 #endif
216
217
218 #ifdef ALT_BITSTREAM_WRITER
219 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
220 {
221 # ifdef ALIGNED_BITSTREAM_WRITER
222 # if defined(ARCH_X86) || defined(ARCH_X86_64)
223 asm volatile(
224 "movl %0, %%ecx \n\t"
225 "xorl %%eax, %%eax \n\t"
226 "shrdl %%cl, %1, %%eax \n\t"
227 "shrl %%cl, %1 \n\t"
228 "movl %0, %%ecx \n\t"
229 "shrl $3, %%ecx \n\t"
230 "andl $0xFFFFFFFC, %%ecx \n\t"
231 "bswapl %1 \n\t"
232 "orl %1, (%2, %%ecx) \n\t"
233 "bswapl %%eax \n\t"
234 "addl %3, %0 \n\t"
235 "movl %%eax, 4(%2, %%ecx) \n\t"
236 : "=&r" (s->index), "=&r" (value)
237 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
238 : "%eax", "%ecx"
239 );
240 # else
241 int index= s->index;
242 uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
243
244 value<<= 32-n;
245
246 ptr[0] |= be2me_32(value>>(index&31));
247 ptr[1] = be2me_32(value<<(32-(index&31)));
248 //if(n>24) printf("%d %d\n", n, value);
249 index+= n;
250 s->index= index;
251 # endif
252 # else //ALIGNED_BITSTREAM_WRITER
253 # if defined(ARCH_X86) || defined(ARCH_X86_64)
254 asm volatile(
255 "movl $7, %%ecx \n\t"
256 "andl %0, %%ecx \n\t"
257 "addl %3, %%ecx \n\t"
258 "negl %%ecx \n\t"
259 "shll %%cl, %1 \n\t"
260 "bswapl %1 \n\t"
261 "movl %0, %%ecx \n\t"
262 "shrl $3, %%ecx \n\t"
263 "orl %1, (%%ecx, %2) \n\t"
264 "addl %3, %0 \n\t"
265 "movl $0, 4(%%ecx, %2) \n\t"
266 : "=&r" (s->index), "=&r" (value)
267 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
268 : "%ecx"
269 );
270 # else
271 int index= s->index;
272 uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
273
274 ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
275 ptr[1] = 0;
276 //if(n>24) printf("%d %d\n", n, value);
277 index+= n;
278 s->index= index;
279 # endif
280 # endif //!ALIGNED_BITSTREAM_WRITER
281 }
282 #endif
283
284
285 static inline uint8_t* pbBufPtr(PutBitContext *s)
286 {
287 #ifdef ALT_BITSTREAM_WRITER
288 return s->buf + (s->index>>3);
289 #else
290 return s->buf_ptr;
291 #endif
292 }
293
294 /**
295 *
296 * PutBitContext must be flushed & aligned to a byte boundary before calling this.
297 */
298 static inline void skip_put_bytes(PutBitContext *s, int n){
299 assert((put_bits_count(s)&7)==0);
300 #ifdef ALT_BITSTREAM_WRITER
301 FIXME may need some cleaning of the buffer
302 s->index += n<<3;
303 #else
304 assert(s->bit_left==32);
305 s->buf_ptr += n;
306 #endif
307 }
308
309 /**
310 * skips the given number of bits.
311 * must only be used if the actual values in the bitstream dont matter
312 */
313 static inline void skip_put_bits(PutBitContext *s, int n){
314 #ifdef ALT_BITSTREAM_WRITER
315 s->index += n;
316 #else
317 s->bit_left -= n;
318 s->buf_ptr-= s->bit_left>>5;
319 s->bit_left &= 31;
320 #endif
321 }
322
323 /**
324 * Changes the end of the buffer.
325 */
326 static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
327 s->buf_end= s->buf + size;
328 }
329
330 /* Bitstream reader API docs:
331 name
332 abritary name which is used as prefix for the internal variables
333
334 gb
335 getbitcontext
336
337 OPEN_READER(name, gb)
338 loads gb into local variables
339
340 CLOSE_READER(name, gb)
341 stores local vars in gb
342
343 UPDATE_CACHE(name, gb)
344 refills the internal cache from the bitstream
345 after this call at least MIN_CACHE_BITS will be available,
346
347 GET_CACHE(name, gb)
348 will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
349
350 SHOW_UBITS(name, gb, num)
351 will return the next num bits
352
353 SHOW_SBITS(name, gb, num)
354 will return the next num bits and do sign extension
355
356 SKIP_BITS(name, gb, num)
357 will skip over the next num bits
358 note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
359
360 SKIP_CACHE(name, gb, num)
361 will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
362
363 SKIP_COUNTER(name, gb, num)
364 will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
365
366 LAST_SKIP_CACHE(name, gb, num)
367 will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
368
369 LAST_SKIP_BITS(name, gb, num)
370 is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
371
372 for examples see get_bits, show_bits, skip_bits, get_vlc
373 */
374
375 static inline int unaligned32_be(const void *v)
376 {
377 #ifdef CONFIG_ALIGN
378 const uint8_t *p=v;
379 return (((p[0]<<8) | p[1])<<16) | (p[2]<<8) | (p[3]);
380 #else
381 return be2me_32( unaligned32(v)); //original
382 #endif
383 }
384
385 static inline int unaligned32_le(const void *v)
386 {
387 #ifdef CONFIG_ALIGN
388 const uint8_t *p=v;
389 return (((p[3]<<8) | p[2])<<16) | (p[1]<<8) | (p[0]);
390 #else
391 return le2me_32( unaligned32(v)); //original
392 #endif
393 }
394
395 #ifdef ALT_BITSTREAM_READER
396 # define MIN_CACHE_BITS 25
397
398 # define OPEN_READER(name, gb)\
399 int name##_index= (gb)->index;\
400 int name##_cache= 0;\
401
402 # define CLOSE_READER(name, gb)\
403 (gb)->index= name##_index;\
404
405 # ifdef ALT_BITSTREAM_READER_LE
406 # define UPDATE_CACHE(name, gb)\
407 name##_cache= unaligned32_le( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
408
409 # define SKIP_CACHE(name, gb, num)\
410 name##_cache >>= (num);
411 # else
412 # define UPDATE_CACHE(name, gb)\
413 name##_cache= unaligned32_be( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
414
415 # define SKIP_CACHE(name, gb, num)\
416 name##_cache <<= (num);
417 # endif
418
419 // FIXME name?
420 # define SKIP_COUNTER(name, gb, num)\
421 name##_index += (num);\
422
423 # define SKIP_BITS(name, gb, num)\
424 {\
425 SKIP_CACHE(name, gb, num)\
426 SKIP_COUNTER(name, gb, num)\
427 }\
428
429 # define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
430 # define LAST_SKIP_CACHE(name, gb, num) ;
431
432 # ifdef ALT_BITSTREAM_READER_LE
433 # define SHOW_UBITS(name, gb, num)\
434 ((name##_cache) & (NEG_USR32(0xffffffff,num)))
435 # else
436 # define SHOW_UBITS(name, gb, num)\
437 NEG_USR32(name##_cache, num)
438 # endif
439
440 # define SHOW_SBITS(name, gb, num)\
441 NEG_SSR32(name##_cache, num)
442
443 # define GET_CACHE(name, gb)\
444 ((uint32_t)name##_cache)
445
446 static inline int get_bits_count(GetBitContext *s){
447 return s->index;
448 }
449 #elif defined LIBMPEG2_BITSTREAM_READER
450 //libmpeg2 like reader
451
452 # define MIN_CACHE_BITS 17
453
454 # define OPEN_READER(name, gb)\
455 int name##_bit_count=(gb)->bit_count;\
456 int name##_cache= (gb)->cache;\
457 uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
458
459 # define CLOSE_READER(name, gb)\
460 (gb)->bit_count= name##_bit_count;\
461 (gb)->cache= name##_cache;\
462 (gb)->buffer_ptr= name##_buffer_ptr;\
463
464 #ifdef LIBMPEG2_BITSTREAM_READER_HACK
465
466 # define UPDATE_CACHE(name, gb)\
467 if(name##_bit_count >= 0){\
468 name##_cache+= (int)be2me_16(*(uint16_t*)name##_buffer_ptr) << name##_bit_count;\
469 name##_buffer_ptr += 2;\
470 name##_bit_count-= 16;\
471 }\
472
473 #else
474
475 # define UPDATE_CACHE(name, gb)\
476 if(name##_bit_count >= 0){\
477 name##_cache+= ((name##_buffer_ptr[0]<<8) + name##_buffer_ptr[1]) << name##_bit_count;\
478 name##_buffer_ptr+=2;\
479 name##_bit_count-= 16;\
480 }\
481
482 #endif
483
484 # define SKIP_CACHE(name, gb, num)\
485 name##_cache <<= (num);\
486
487 # define SKIP_COUNTER(name, gb, num)\
488 name##_bit_count += (num);\
489
490 # define SKIP_BITS(name, gb, num)\
491 {\
492 SKIP_CACHE(name, gb, num)\
493 SKIP_COUNTER(name, gb, num)\
494 }\
495
496 # define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
497 # define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
498
499 # define SHOW_UBITS(name, gb, num)\
500 NEG_USR32(name##_cache, num)
501
502 # define SHOW_SBITS(name, gb, num)\
503 NEG_SSR32(name##_cache, num)
504
505 # define GET_CACHE(name, gb)\
506 ((uint32_t)name##_cache)
507
508 static inline int get_bits_count(GetBitContext *s){
509 return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
510 }
511
512 #elif defined A32_BITSTREAM_READER
513
514 # define MIN_CACHE_BITS 32
515
516 # define OPEN_READER(name, gb)\
517 int name##_bit_count=(gb)->bit_count;\
518 uint32_t name##_cache0= (gb)->cache0;\
519 uint32_t name##_cache1= (gb)->cache1;\
520 uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
521
522 # define CLOSE_READER(name, gb)\
523 (gb)->bit_count= name##_bit_count;\
524 (gb)->cache0= name##_cache0;\
525 (gb)->cache1= name##_cache1;\
526 (gb)->buffer_ptr= name##_buffer_ptr;\
527
528 # define UPDATE_CACHE(name, gb)\
529 if(name##_bit_count > 0){\
530 const uint32_t next= be2me_32( *name##_buffer_ptr );\
531 name##_cache0 |= NEG_USR32(next,name##_bit_count);\
532 name##_cache1 |= next<<name##_bit_count;\
533 name##_buffer_ptr++;\
534 name##_bit_count-= 32;\
535 }\
536
537 #if defined(ARCH_X86) || defined(ARCH_X86_64)
538 # define SKIP_CACHE(name, gb, num)\
539 asm(\
540 "shldl %2, %1, %0 \n\t"\
541 "shll %2, %1 \n\t"\
542 : "+r" (name##_cache0), "+r" (name##_cache1)\
543 : "Ic" ((uint8_t)num)\
544 );
545 #else
546 # define SKIP_CACHE(name, gb, num)\
547 name##_cache0 <<= (num);\
548 name##_cache0 |= NEG_USR32(name##_cache1,num);\
549 name##_cache1 <<= (num);
550 #endif
551
552 # define SKIP_COUNTER(name, gb, num)\
553 name##_bit_count += (num);\
554
555 # define SKIP_BITS(name, gb, num)\
556 {\
557 SKIP_CACHE(name, gb, num)\
558 SKIP_COUNTER(name, gb, num)\
559 }\
560
561 # define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
562 # define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
563
564 # define SHOW_UBITS(name, gb, num)\
565 NEG_USR32(name##_cache0, num)
566
567 # define SHOW_SBITS(name, gb, num)\
568 NEG_SSR32(name##_cache0, num)
569
570 # define GET_CACHE(name, gb)\
571 (name##_cache0)
572
573 static inline int get_bits_count(GetBitContext *s){
574 return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
575 }
576
577 #endif
578
579 /**
580 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
581 * if MSB not set it is negative
582 * @param n length in bits
583 * @author BERO
584 */
585 static inline int get_xbits(GetBitContext *s, int n){
586 register int sign;
587 register int32_t cache;
588 OPEN_READER(re, s)
589 UPDATE_CACHE(re, s)
590 cache = GET_CACHE(re,s);
591 sign=(~cache)>>31;
592 LAST_SKIP_BITS(re, s, n)
593 CLOSE_READER(re, s)
594 return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
595 }
596
597 static inline int get_sbits(GetBitContext *s, int n){
598 register int tmp;
599 OPEN_READER(re, s)
600 UPDATE_CACHE(re, s)
601 tmp= SHOW_SBITS(re, s, n);
602 LAST_SKIP_BITS(re, s, n)
603 CLOSE_READER(re, s)
604 return tmp;
605 }
606
607 /**
608 * reads 0-17 bits.
609 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
610 */
611 static inline unsigned int get_bits(GetBitContext *s, int n){
612 register int tmp;
613 OPEN_READER(re, s)
614 UPDATE_CACHE(re, s)
615 tmp= SHOW_UBITS(re, s, n);
616 LAST_SKIP_BITS(re, s, n)
617 CLOSE_READER(re, s)
618 return tmp;
619 }
620
621 unsigned int get_bits_long(GetBitContext *s, int n);
622
623 /**
624 * shows 0-17 bits.
625 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
626 */
627 static inline unsigned int show_bits(GetBitContext *s, int n){
628 register int tmp;
629 OPEN_READER(re, s)
630 UPDATE_CACHE(re, s)
631 tmp= SHOW_UBITS(re, s, n);
632 // CLOSE_READER(re, s)
633 return tmp;
634 }
635
636 unsigned int show_bits_long(GetBitContext *s, int n);
637
638 static inline void skip_bits(GetBitContext *s, int n){
639 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
640 OPEN_READER(re, s)
641 UPDATE_CACHE(re, s)
642 LAST_SKIP_BITS(re, s, n)
643 CLOSE_READER(re, s)
644 }
645
646 static inline unsigned int get_bits1(GetBitContext *s){
647 #ifdef ALT_BITSTREAM_READER
648 int index= s->index;
649 uint8_t result= s->buffer[ index>>3 ];
650 #ifdef ALT_BITSTREAM_READER_LE
651 result>>= (index&0x07);
652 result&= 1;
653 #else
654 result<<= (index&0x07);
655 result>>= 8 - 1;
656 #endif
657 index++;
658 s->index= index;
659
660 return result;
661 #else
662 return get_bits(s, 1);
663 #endif
664 }
665
666 static inline unsigned int show_bits1(GetBitContext *s){
667 return show_bits(s, 1);
668 }
669
670 static inline void skip_bits1(GetBitContext *s){
671 skip_bits(s, 1);
672 }
673
674 /**
675 * init GetBitContext.
676 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
677 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
678 * @param bit_size the size of the buffer in bits
679 */
680 static inline void init_get_bits(GetBitContext *s,
681 const uint8_t *buffer, int bit_size)
682 {
683 int buffer_size= (bit_size+7)>>3;
684 if(buffer_size < 0 || bit_size < 0) {
685 buffer_size = bit_size = 0;
686 buffer = NULL;
687 }
688
689 s->buffer= buffer;
690 s->size_in_bits= bit_size;
691 s->buffer_end= buffer + buffer_size;
692 #ifdef ALT_BITSTREAM_READER
693 s->index=0;
694 #elif defined LIBMPEG2_BITSTREAM_READER
695 #ifdef LIBMPEG2_BITSTREAM_READER_HACK
696 if ((int)buffer&1) {
697 /* word alignment */
698 s->cache = (*buffer++)<<24;
699 s->buffer_ptr = buffer;
700 s->bit_count = 16-8;
701 } else
702 #endif
703 {
704 s->buffer_ptr = buffer;
705 s->bit_count = 16;
706 s->cache = 0;
707 }
708 #elif defined A32_BITSTREAM_READER
709 s->buffer_ptr = (uint32_t*)buffer;
710 s->bit_count = 32;
711 s->cache0 = 0;
712 s->cache1 = 0;
713 #endif
714 {
715 OPEN_READER(re, s)
716 UPDATE_CACHE(re, s)
717 UPDATE_CACHE(re, s)
718 CLOSE_READER(re, s)
719 }
720 #ifdef A32_BITSTREAM_READER
721 s->cache1 = 0;
722 #endif
723 }
724
725 int check_marker(GetBitContext *s, const char *msg);
726 void align_get_bits(GetBitContext *s);
727 int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
728 const void *bits, int bits_wrap, int bits_size,
729 const void *codes, int codes_wrap, int codes_size,
730 int flags);
731 #define INIT_VLC_USE_STATIC 1
732 #define INIT_VLC_LE 2
733 void free_vlc(VLC *vlc);
734
735 /**
736 *
737 * if the vlc code is invalid and max_depth=1 than no bits will be removed
738 * if the vlc code is invalid and max_depth>1 than the number of bits removed
739 * is undefined
740 */
741 #define GET_VLC(code, name, gb, table, bits, max_depth)\
742 {\
743 int n, index, nb_bits;\
744 \
745 index= SHOW_UBITS(name, gb, bits);\
746 code = table[index][0];\
747 n = table[index][1];\
748 \
749 if(max_depth > 1 && n < 0){\
750 LAST_SKIP_BITS(name, gb, bits)\
751 UPDATE_CACHE(name, gb)\
752 \
753 nb_bits = -n;\
754 \
755 index= SHOW_UBITS(name, gb, nb_bits) + code;\
756 code = table[index][0];\
757 n = table[index][1];\
758 if(max_depth > 2 && n < 0){\
759 LAST_SKIP_BITS(name, gb, nb_bits)\
760 UPDATE_CACHE(name, gb)\
761 \
762 nb_bits = -n;\
763 \
764 index= SHOW_UBITS(name, gb, nb_bits) + code;\
765 code = table[index][0];\
766 n = table[index][1];\
767 }\
768 }\
769 SKIP_BITS(name, gb, n)\
770 }
771
772 #define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
773 {\
774 int n, index, nb_bits;\
775 \
776 index= SHOW_UBITS(name, gb, bits);\
777 level = table[index].level;\
778 n = table[index].len;\
779 \
780 if(max_depth > 1 && n < 0){\
781 SKIP_BITS(name, gb, bits)\
782 if(need_update){\
783 UPDATE_CACHE(name, gb)\
784 }\
785 \
786 nb_bits = -n;\
787 \
788 index= SHOW_UBITS(name, gb, nb_bits) + level;\
789 level = table[index].level;\
790 n = table[index].len;\
791 }\
792 run= table[index].run;\
793 SKIP_BITS(name, gb, n)\
794 }
795
796
797 /**
798 * parses a vlc code, faster then get_vlc()
799 * @param bits is the number of bits which will be read at once, must be
800 * identical to nb_bits in init_vlc()
801 * @param max_depth is the number of times bits bits must be readed to completly
802 * read the longest vlc code
803 * = (max_vlc_length + bits - 1) / bits
804 */
805 static always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
806 int bits, int max_depth)
807 {
808 int code;
809
810 OPEN_READER(re, s)
811 UPDATE_CACHE(re, s)
812
813 GET_VLC(code, re, s, table, bits, max_depth)
814
815 CLOSE_READER(re, s)
816 return code;
817 }
818
819 //#define TRACE
820
821 #ifdef TRACE
822 #include "avcodec.h"
823 static inline void print_bin(int bits, int n){
824 int i;
825
826 for(i=n-1; i>=0; i--){
827 av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
828 }
829 for(i=n; i<24; i++)
830 av_log(NULL, AV_LOG_DEBUG, " ");
831 }
832
833 static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
834 int r= get_bits(s, n);
835
836 print_bin(r, n);
837 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);
838 return r;
839 }
840 static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
841 int show= show_bits(s, 24);
842 int pos= get_bits_count(s);
843 int r= get_vlc2(s, table, bits, max_depth);
844 int len= get_bits_count(s) - pos;
845 int bits2= show>>(24-len);
846
847 print_bin(bits2, len);
848
849 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
850 return r;
851 }
852 static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
853 int show= show_bits(s, n);
854 int r= get_xbits(s, n);
855
856 print_bin(show, n);
857 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);
858 return r;
859 }
860
861 #define get_bits(s, n) get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
862 #define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
863 #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
864 #define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
865 #define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
866
867 #define tprintf(...) av_log(NULL, AV_LOG_DEBUG, __VA_ARGS__)
868
869 #else //TRACE
870 #define tprintf(...) {}
871 #endif
872
873 static inline int decode012(GetBitContext *gb){
874 int n;
875 n = get_bits1(gb);
876 if (n == 0)
877 return 0;
878 else
879 return get_bits1(gb) + 1;
880 }
881
882 #endif /* BITSTREAM_H */