0b336f747f80ef56b46e8f8a5d1900883fca85e6
[libav.git] / 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 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
53 extern const uint8_t ff_reverse[256];
54
55 #if 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 int size_in_bits;
89 } PutBitContext;
90
91 static 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 */
113 static 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 */
123 static 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
147 void align_put_bits(PutBitContext *s);
148 void ff_put_string(PutBitContext * pbc, const char *s, int put_zero);
149 void 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 */
153 typedef 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
172 typedef struct VLC {
173 int bits;
174 VLC_TYPE (*table)[2]; ///< code, bits
175 int table_size, table_allocated;
176 } VLC;
177
178 typedef 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
185 static 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
239 static 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
304 static 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
312 static 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 */
325 static 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 */
340 static 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 */
353 static 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:
358 name
359 arbitrary name which is used as prefix for the internal variables
360
361 gb
362 getbitcontext
363
364 OPEN_READER(name, gb)
365 loads gb into local variables
366
367 CLOSE_READER(name, gb)
368 stores local vars in gb
369
370 UPDATE_CACHE(name, gb)
371 refills the internal cache from the bitstream
372 after this call at least MIN_CACHE_BITS will be available,
373
374 GET_CACHE(name, gb)
375 will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
376
377 SHOW_UBITS(name, gb, num)
378 will return the next num bits
379
380 SHOW_SBITS(name, gb, num)
381 will return the next num bits and do sign extension
382
383 SKIP_BITS(name, gb, num)
384 will skip over the next num bits
385 note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
386
387 SKIP_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
390 SKIP_COUNTER(name, gb, num)
391 will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
392
393 LAST_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
396 LAST_SKIP_BITS(name, gb, num)
397 is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
398
399 for 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
456 static inline int get_bits_count(GetBitContext *s){
457 return s->index;
458 }
459
460 static 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
510 static inline int get_bits_count(GetBitContext *s){
511 return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
512 }
513
514 static 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
585 static inline int get_bits_count(GetBitContext *s){
586 return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
587 }
588
589 static 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 */
608 static 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
620 static 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 */
634 static 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 */
648 static 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
657 static 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
665 static 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
685 static inline unsigned int show_bits1(GetBitContext *s){
686 return show_bits(s, 1);
687 }
688
689 static inline void skip_bits1(GetBitContext *s){
690 skip_bits(s, 1);
691 }
692
693 /**
694 * reads 0-32 bits.
695 */
696 static 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 */
712 static 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 return get_bits_long(&gb, n);
717 }
718 }
719
720 static inline int check_marker(GetBitContext *s, const char *msg)
721 {
722 int bit= get_bits1(s);
723 if(!bit)
724 av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
725
726 return bit;
727 }
728
729 /**
730 * init GetBitContext.
731 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
732 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
733 * @param bit_size the size of the buffer in bits
734 */
735 static inline void init_get_bits(GetBitContext *s,
736 const uint8_t *buffer, int bit_size)
737 {
738 int buffer_size= (bit_size+7)>>3;
739 if(buffer_size < 0 || bit_size < 0) {
740 buffer_size = bit_size = 0;
741 buffer = NULL;
742 }
743
744 s->buffer= buffer;
745 s->size_in_bits= bit_size;
746 s->buffer_end= buffer + buffer_size;
747 #ifdef ALT_BITSTREAM_READER
748 s->index=0;
749 #elif defined LIBMPEG2_BITSTREAM_READER
750 s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
751 s->bit_count = 16 + 8*((intptr_t)buffer&1);
752 skip_bits_long(s, 0);
753 #elif defined A32_BITSTREAM_READER
754 s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
755 s->bit_count = 32 + 8*((intptr_t)buffer&3);
756 skip_bits_long(s, 0);
757 #endif
758 }
759
760 static inline void align_get_bits(GetBitContext *s)
761 {
762 int n= (-get_bits_count(s)) & 7;
763 if(n) skip_bits(s, n);
764 }
765
766 #define init_vlc(vlc, nb_bits, nb_codes,\
767 bits, bits_wrap, bits_size,\
768 codes, codes_wrap, codes_size,\
769 flags)\
770 init_vlc_sparse(vlc, nb_bits, nb_codes,\
771 bits, bits_wrap, bits_size,\
772 codes, codes_wrap, codes_size,\
773 NULL, 0, 0, flags)
774
775 int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
776 const void *bits, int bits_wrap, int bits_size,
777 const void *codes, int codes_wrap, int codes_size,
778 const void *symbols, int symbols_wrap, int symbols_size,
779 int flags);
780 #define INIT_VLC_USE_STATIC 1 ///< VERY strongly deprecated and forbidden
781 #define INIT_VLC_LE 2
782 #define INIT_VLC_USE_NEW_STATIC 4
783 void free_vlc(VLC *vlc);
784
785 #define INIT_VLC_STATIC(vlc, bits, a,b,c,d,e,f,g, static_size)\
786 {\
787 static VLC_TYPE table[static_size][2];\
788 (vlc)->table= table;\
789 (vlc)->table_allocated= static_size;\
790 init_vlc(vlc, bits, a,b,c,d,e,f,g, INIT_VLC_USE_NEW_STATIC);\
791 }
792
793
794 /**
795 *
796 * if the vlc code is invalid and max_depth=1 than no bits will be removed
797 * if the vlc code is invalid and max_depth>1 than the number of bits removed
798 * is undefined
799 */
800 #define GET_VLC(code, name, gb, table, bits, max_depth)\
801 {\
802 int n, index, nb_bits;\
803 \
804 index= SHOW_UBITS(name, gb, bits);\
805 code = table[index][0];\
806 n = table[index][1];\
807 \
808 if(max_depth > 1 && n < 0){\
809 LAST_SKIP_BITS(name, gb, bits)\
810 UPDATE_CACHE(name, gb)\
811 \
812 nb_bits = -n;\
813 \
814 index= SHOW_UBITS(name, gb, nb_bits) + code;\
815 code = table[index][0];\
816 n = table[index][1];\
817 if(max_depth > 2 && n < 0){\
818 LAST_SKIP_BITS(name, gb, nb_bits)\
819 UPDATE_CACHE(name, gb)\
820 \
821 nb_bits = -n;\
822 \
823 index= SHOW_UBITS(name, gb, nb_bits) + code;\
824 code = table[index][0];\
825 n = table[index][1];\
826 }\
827 }\
828 SKIP_BITS(name, gb, n)\
829 }
830
831 #define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
832 {\
833 int n, index, nb_bits;\
834 \
835 index= SHOW_UBITS(name, gb, bits);\
836 level = table[index].level;\
837 n = table[index].len;\
838 \
839 if(max_depth > 1 && n < 0){\
840 SKIP_BITS(name, gb, bits)\
841 if(need_update){\
842 UPDATE_CACHE(name, gb)\
843 }\
844 \
845 nb_bits = -n;\
846 \
847 index= SHOW_UBITS(name, gb, nb_bits) + level;\
848 level = table[index].level;\
849 n = table[index].len;\
850 }\
851 run= table[index].run;\
852 SKIP_BITS(name, gb, n)\
853 }
854
855
856 /**
857 * parses a vlc code, faster then get_vlc()
858 * @param bits is the number of bits which will be read at once, must be
859 * identical to nb_bits in init_vlc()
860 * @param max_depth is the number of times bits bits must be read to completely
861 * read the longest vlc code
862 * = (max_vlc_length + bits - 1) / bits
863 */
864 static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
865 int bits, int max_depth)
866 {
867 int code;
868
869 OPEN_READER(re, s)
870 UPDATE_CACHE(re, s)
871
872 GET_VLC(code, re, s, table, bits, max_depth)
873
874 CLOSE_READER(re, s)
875 return code;
876 }
877
878 //#define TRACE
879
880 #ifdef TRACE
881 static inline void print_bin(int bits, int n){
882 int i;
883
884 for(i=n-1; i>=0; i--){
885 av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
886 }
887 for(i=n; i<24; i++)
888 av_log(NULL, AV_LOG_DEBUG, " ");
889 }
890
891 static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
892 int r= get_bits(s, n);
893
894 print_bin(r, n);
895 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);
896 return r;
897 }
898 static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
899 int show= show_bits(s, 24);
900 int pos= get_bits_count(s);
901 int r= get_vlc2(s, table, bits, max_depth);
902 int len= get_bits_count(s) - pos;
903 int bits2= show>>(24-len);
904
905 print_bin(bits2, len);
906
907 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
908 return r;
909 }
910 static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
911 int show= show_bits(s, n);
912 int r= get_xbits(s, n);
913
914 print_bin(show, n);
915 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);
916 return r;
917 }
918
919 #define get_bits(s, n) get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
920 #define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
921 #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
922 #define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
923 #define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
924
925 #define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
926
927 #else //TRACE
928 #define tprintf(p, ...) {}
929 #endif
930
931 static inline int decode012(GetBitContext *gb){
932 int n;
933 n = get_bits1(gb);
934 if (n == 0)
935 return 0;
936 else
937 return get_bits1(gb) + 1;
938 }
939
940 static inline int decode210(GetBitContext *gb){
941 if (get_bits1(gb))
942 return 0;
943 else
944 return 2 - get_bits1(gb);
945 }
946
947 #endif /* AVCODEC_BITSTREAM_H */