0f8110612a2a6f8e02daa70a0ce1ed74402694d1
[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 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 } 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 #ifndef BITSTREAM_WRITER_LE
127 s->bit_buf<<= s->bit_left;
128 #endif
129 while (s->bit_left < 32) {
130 /* XXX: should test end of buffer */
131 #ifdef BITSTREAM_WRITER_LE
132 *s->buf_ptr++=s->bit_buf;
133 s->bit_buf>>=8;
134 #else
135 *s->buf_ptr++=s->bit_buf >> 24;
136 s->bit_buf<<=8;
137 #endif
138 s->bit_left+=8;
139 }
140 s->bit_left=32;
141 s->bit_buf=0;
142 #endif
143 }
144
145 void align_put_bits(PutBitContext *s);
146 void ff_put_string(PutBitContext * pbc, const char *s, int put_zero);
147 void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length);
148
149 /* bit input */
150 /* buffer, buffer_end and size_in_bits must be present and used by every reader */
151 typedef struct GetBitContext {
152 const uint8_t *buffer, *buffer_end;
153 #ifdef ALT_BITSTREAM_READER
154 int index;
155 #elif defined LIBMPEG2_BITSTREAM_READER
156 uint8_t *buffer_ptr;
157 uint32_t cache;
158 int bit_count;
159 #elif defined A32_BITSTREAM_READER
160 uint32_t *buffer_ptr;
161 uint32_t cache0;
162 uint32_t cache1;
163 int bit_count;
164 #endif
165 int size_in_bits;
166 } GetBitContext;
167
168 #define VLC_TYPE int16_t
169
170 typedef struct VLC {
171 int bits;
172 VLC_TYPE (*table)[2]; ///< code, bits
173 int table_size, table_allocated;
174 } VLC;
175
176 typedef struct RL_VLC_ELEM {
177 int16_t level;
178 int8_t len;
179 uint8_t run;
180 } RL_VLC_ELEM;
181
182 #ifndef ALT_BITSTREAM_WRITER
183 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
184 {
185 unsigned int bit_buf;
186 int bit_left;
187
188 // printf("put_bits=%d %x\n", n, value);
189 assert(n == 32 || value < (1U << n));
190
191 bit_buf = s->bit_buf;
192 bit_left = s->bit_left;
193
194 // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
195 /* XXX: optimize */
196 #ifdef BITSTREAM_WRITER_LE
197 bit_buf |= value << (32 - bit_left);
198 if (n >= bit_left) {
199 #if !HAVE_FAST_UNALIGNED
200 if (3 & (intptr_t) s->buf_ptr) {
201 s->buf_ptr[0] = bit_buf ;
202 s->buf_ptr[1] = bit_buf >> 8;
203 s->buf_ptr[2] = bit_buf >> 16;
204 s->buf_ptr[3] = bit_buf >> 24;
205 } else
206 #endif
207 *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
208 s->buf_ptr+=4;
209 bit_buf = (bit_left==32)?0:value >> bit_left;
210 bit_left+=32;
211 }
212 bit_left-=n;
213 #else
214 if (n < bit_left) {
215 bit_buf = (bit_buf<<n) | value;
216 bit_left-=n;
217 } else {
218 bit_buf<<=bit_left;
219 bit_buf |= value >> (n - bit_left);
220 #if !HAVE_FAST_UNALIGNED
221 if (3 & (intptr_t) s->buf_ptr) {
222 s->buf_ptr[0] = bit_buf >> 24;
223 s->buf_ptr[1] = bit_buf >> 16;
224 s->buf_ptr[2] = bit_buf >> 8;
225 s->buf_ptr[3] = bit_buf ;
226 } else
227 #endif
228 *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
229 //printf("bitbuf = %08x\n", bit_buf);
230 s->buf_ptr+=4;
231 bit_left+=32 - n;
232 bit_buf = value;
233 }
234 #endif
235
236 s->bit_buf = bit_buf;
237 s->bit_left = bit_left;
238 }
239 #endif
240
241
242 #ifdef ALT_BITSTREAM_WRITER
243 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
244 {
245 # ifdef ALIGNED_BITSTREAM_WRITER
246 # if ARCH_X86
247 __asm__ volatile(
248 "movl %0, %%ecx \n\t"
249 "xorl %%eax, %%eax \n\t"
250 "shrdl %%cl, %1, %%eax \n\t"
251 "shrl %%cl, %1 \n\t"
252 "movl %0, %%ecx \n\t"
253 "shrl $3, %%ecx \n\t"
254 "andl $0xFFFFFFFC, %%ecx \n\t"
255 "bswapl %1 \n\t"
256 "orl %1, (%2, %%ecx) \n\t"
257 "bswapl %%eax \n\t"
258 "addl %3, %0 \n\t"
259 "movl %%eax, 4(%2, %%ecx) \n\t"
260 : "=&r" (s->index), "=&r" (value)
261 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
262 : "%eax", "%ecx"
263 );
264 # else
265 int index= s->index;
266 uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
267
268 value<<= 32-n;
269
270 ptr[0] |= be2me_32(value>>(index&31));
271 ptr[1] = be2me_32(value<<(32-(index&31)));
272 //if(n>24) printf("%d %d\n", n, value);
273 index+= n;
274 s->index= index;
275 # endif
276 # else //ALIGNED_BITSTREAM_WRITER
277 # if ARCH_X86
278 __asm__ volatile(
279 "movl $7, %%ecx \n\t"
280 "andl %0, %%ecx \n\t"
281 "addl %3, %%ecx \n\t"
282 "negl %%ecx \n\t"
283 "shll %%cl, %1 \n\t"
284 "bswapl %1 \n\t"
285 "movl %0, %%ecx \n\t"
286 "shrl $3, %%ecx \n\t"
287 "orl %1, (%%ecx, %2) \n\t"
288 "addl %3, %0 \n\t"
289 "movl $0, 4(%%ecx, %2) \n\t"
290 : "=&r" (s->index), "=&r" (value)
291 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
292 : "%ecx"
293 );
294 # else
295 int index= s->index;
296 uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
297
298 ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
299 ptr[1] = 0;
300 //if(n>24) printf("%d %d\n", n, value);
301 index+= n;
302 s->index= index;
303 # endif
304 # endif //!ALIGNED_BITSTREAM_WRITER
305 }
306 #endif
307
308 static inline void put_sbits(PutBitContext *pb, int bits, int32_t val)
309 {
310 assert(bits >= 0 && bits <= 31);
311
312 put_bits(pb, bits, val & ((1<<bits)-1));
313 }
314
315
316 static inline uint8_t* pbBufPtr(PutBitContext *s)
317 {
318 #ifdef ALT_BITSTREAM_WRITER
319 return s->buf + (s->index>>3);
320 #else
321 return s->buf_ptr;
322 #endif
323 }
324
325 /**
326 *
327 * PutBitContext must be flushed & aligned to a byte boundary before calling this.
328 */
329 static inline void skip_put_bytes(PutBitContext *s, int n){
330 assert((put_bits_count(s)&7)==0);
331 #ifdef ALT_BITSTREAM_WRITER
332 FIXME may need some cleaning of the buffer
333 s->index += n<<3;
334 #else
335 assert(s->bit_left==32);
336 s->buf_ptr += n;
337 #endif
338 }
339
340 /**
341 * Skips the given number of bits.
342 * Must only be used if the actual values in the bitstream do not matter.
343 */
344 static inline void skip_put_bits(PutBitContext *s, int n){
345 #ifdef ALT_BITSTREAM_WRITER
346 s->index += n;
347 #else
348 s->bit_left -= n;
349 s->buf_ptr-= s->bit_left>>5;
350 s->bit_left &= 31;
351 #endif
352 }
353
354 /**
355 * Changes the end of the buffer.
356 */
357 static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
358 s->buf_end= s->buf + size;
359 }
360
361 /* Bitstream reader API docs:
362 name
363 arbitrary name which is used as prefix for the internal variables
364
365 gb
366 getbitcontext
367
368 OPEN_READER(name, gb)
369 loads gb into local variables
370
371 CLOSE_READER(name, gb)
372 stores local vars in gb
373
374 UPDATE_CACHE(name, gb)
375 refills the internal cache from the bitstream
376 after this call at least MIN_CACHE_BITS will be available,
377
378 GET_CACHE(name, gb)
379 will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
380
381 SHOW_UBITS(name, gb, num)
382 will return the next num bits
383
384 SHOW_SBITS(name, gb, num)
385 will return the next num bits and do sign extension
386
387 SKIP_BITS(name, gb, num)
388 will skip over the next num bits
389 note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
390
391 SKIP_CACHE(name, gb, num)
392 will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
393
394 SKIP_COUNTER(name, gb, num)
395 will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
396
397 LAST_SKIP_CACHE(name, gb, num)
398 will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
399
400 LAST_SKIP_BITS(name, gb, num)
401 is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
402
403 for examples see get_bits, show_bits, skip_bits, get_vlc
404 */
405
406 #ifdef ALT_BITSTREAM_READER
407 # define MIN_CACHE_BITS 25
408
409 # define OPEN_READER(name, gb)\
410 int name##_index= (gb)->index;\
411 int name##_cache= 0;\
412
413 # define CLOSE_READER(name, gb)\
414 (gb)->index= name##_index;\
415
416 # ifdef ALT_BITSTREAM_READER_LE
417 # define UPDATE_CACHE(name, gb)\
418 name##_cache= AV_RL32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
419
420 # define SKIP_CACHE(name, gb, num)\
421 name##_cache >>= (num);
422 # else
423 # define UPDATE_CACHE(name, gb)\
424 name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
425
426 # define SKIP_CACHE(name, gb, num)\
427 name##_cache <<= (num);
428 # endif
429
430 // FIXME name?
431 # define SKIP_COUNTER(name, gb, num)\
432 name##_index += (num);\
433
434 # define SKIP_BITS(name, gb, num)\
435 {\
436 SKIP_CACHE(name, gb, num)\
437 SKIP_COUNTER(name, gb, num)\
438 }\
439
440 # define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
441 # define LAST_SKIP_CACHE(name, gb, num) ;
442
443 # ifdef ALT_BITSTREAM_READER_LE
444 # define SHOW_UBITS(name, gb, num)\
445 ((name##_cache) & (NEG_USR32(0xffffffff,num)))
446
447 # define SHOW_SBITS(name, gb, num)\
448 NEG_SSR32((name##_cache)<<(32-(num)), num)
449 # else
450 # define SHOW_UBITS(name, gb, num)\
451 NEG_USR32(name##_cache, num)
452
453 # define SHOW_SBITS(name, gb, num)\
454 NEG_SSR32(name##_cache, num)
455 # endif
456
457 # define GET_CACHE(name, gb)\
458 ((uint32_t)name##_cache)
459
460 static inline int get_bits_count(GetBitContext *s){
461 return s->index;
462 }
463
464 static inline void skip_bits_long(GetBitContext *s, int n){
465 s->index += n;
466 }
467
468 #elif defined LIBMPEG2_BITSTREAM_READER
469 //libmpeg2 like reader
470
471 # define MIN_CACHE_BITS 17
472
473 # define OPEN_READER(name, gb)\
474 int name##_bit_count=(gb)->bit_count;\
475 int name##_cache= (gb)->cache;\
476 uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
477
478 # define CLOSE_READER(name, gb)\
479 (gb)->bit_count= name##_bit_count;\
480 (gb)->cache= name##_cache;\
481 (gb)->buffer_ptr= name##_buffer_ptr;\
482
483 # define UPDATE_CACHE(name, gb)\
484 if(name##_bit_count >= 0){\
485 name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count; \
486 name##_buffer_ptr+=2;\
487 name##_bit_count-= 16;\
488 }\
489
490 # define SKIP_CACHE(name, gb, num)\
491 name##_cache <<= (num);\
492
493 # define SKIP_COUNTER(name, gb, num)\
494 name##_bit_count += (num);\
495
496 # define SKIP_BITS(name, gb, num)\
497 {\
498 SKIP_CACHE(name, gb, num)\
499 SKIP_COUNTER(name, gb, num)\
500 }\
501
502 # define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
503 # define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
504
505 # define SHOW_UBITS(name, gb, num)\
506 NEG_USR32(name##_cache, num)
507
508 # define SHOW_SBITS(name, gb, num)\
509 NEG_SSR32(name##_cache, num)
510
511 # define GET_CACHE(name, gb)\
512 ((uint32_t)name##_cache)
513
514 static inline int get_bits_count(GetBitContext *s){
515 return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
516 }
517
518 static inline void skip_bits_long(GetBitContext *s, int n){
519 OPEN_READER(re, s)
520 re_bit_count += n;
521 re_buffer_ptr += 2*(re_bit_count>>4);
522 re_bit_count &= 15;
523 re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
524 UPDATE_CACHE(re, s)
525 CLOSE_READER(re, s)
526 }
527
528 #elif defined A32_BITSTREAM_READER
529
530 # define MIN_CACHE_BITS 32
531
532 # define OPEN_READER(name, gb)\
533 int name##_bit_count=(gb)->bit_count;\
534 uint32_t name##_cache0= (gb)->cache0;\
535 uint32_t name##_cache1= (gb)->cache1;\
536 uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
537
538 # define CLOSE_READER(name, gb)\
539 (gb)->bit_count= name##_bit_count;\
540 (gb)->cache0= name##_cache0;\
541 (gb)->cache1= name##_cache1;\
542 (gb)->buffer_ptr= name##_buffer_ptr;\
543
544 # define UPDATE_CACHE(name, gb)\
545 if(name##_bit_count > 0){\
546 const uint32_t next= be2me_32( *name##_buffer_ptr );\
547 name##_cache0 |= NEG_USR32(next,name##_bit_count);\
548 name##_cache1 |= next<<name##_bit_count;\
549 name##_buffer_ptr++;\
550 name##_bit_count-= 32;\
551 }\
552
553 #if ARCH_X86
554 # define SKIP_CACHE(name, gb, num)\
555 __asm__(\
556 "shldl %2, %1, %0 \n\t"\
557 "shll %2, %1 \n\t"\
558 : "+r" (name##_cache0), "+r" (name##_cache1)\
559 : "Ic" ((uint8_t)(num))\
560 );
561 #else
562 # define SKIP_CACHE(name, gb, num)\
563 name##_cache0 <<= (num);\
564 name##_cache0 |= NEG_USR32(name##_cache1,num);\
565 name##_cache1 <<= (num);
566 #endif
567
568 # define SKIP_COUNTER(name, gb, num)\
569 name##_bit_count += (num);\
570
571 # define SKIP_BITS(name, gb, num)\
572 {\
573 SKIP_CACHE(name, gb, num)\
574 SKIP_COUNTER(name, gb, num)\
575 }\
576
577 # define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
578 # define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
579
580 # define SHOW_UBITS(name, gb, num)\
581 NEG_USR32(name##_cache0, num)
582
583 # define SHOW_SBITS(name, gb, num)\
584 NEG_SSR32(name##_cache0, num)
585
586 # define GET_CACHE(name, gb)\
587 (name##_cache0)
588
589 static inline int get_bits_count(GetBitContext *s){
590 return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
591 }
592
593 static inline void skip_bits_long(GetBitContext *s, int n){
594 OPEN_READER(re, s)
595 re_bit_count += n;
596 re_buffer_ptr += re_bit_count>>5;
597 re_bit_count &= 31;
598 re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
599 re_cache1 = 0;
600 UPDATE_CACHE(re, s)
601 CLOSE_READER(re, s)
602 }
603
604 #endif
605
606 /**
607 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
608 * if MSB not set it is negative
609 * @param n length in bits
610 * @author BERO
611 */
612 static inline int get_xbits(GetBitContext *s, int n){
613 register int sign;
614 register int32_t cache;
615 OPEN_READER(re, s)
616 UPDATE_CACHE(re, s)
617 cache = GET_CACHE(re,s);
618 sign=(~cache)>>31;
619 LAST_SKIP_BITS(re, s, n)
620 CLOSE_READER(re, s)
621 return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
622 }
623
624 static inline int get_sbits(GetBitContext *s, int n){
625 register int tmp;
626 OPEN_READER(re, s)
627 UPDATE_CACHE(re, s)
628 tmp= SHOW_SBITS(re, s, n);
629 LAST_SKIP_BITS(re, s, n)
630 CLOSE_READER(re, s)
631 return tmp;
632 }
633
634 /**
635 * reads 1-17 bits.
636 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
637 */
638 static inline unsigned int get_bits(GetBitContext *s, int n){
639 register int tmp;
640 OPEN_READER(re, s)
641 UPDATE_CACHE(re, s)
642 tmp= SHOW_UBITS(re, s, n);
643 LAST_SKIP_BITS(re, s, n)
644 CLOSE_READER(re, s)
645 return tmp;
646 }
647
648 /**
649 * shows 1-17 bits.
650 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
651 */
652 static inline unsigned int show_bits(GetBitContext *s, int n){
653 register int tmp;
654 OPEN_READER(re, s)
655 UPDATE_CACHE(re, s)
656 tmp= SHOW_UBITS(re, s, n);
657 // CLOSE_READER(re, s)
658 return tmp;
659 }
660
661 static inline void skip_bits(GetBitContext *s, int n){
662 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
663 OPEN_READER(re, s)
664 UPDATE_CACHE(re, s)
665 LAST_SKIP_BITS(re, s, n)
666 CLOSE_READER(re, s)
667 }
668
669 static inline unsigned int get_bits1(GetBitContext *s){
670 #ifdef ALT_BITSTREAM_READER
671 int index= s->index;
672 uint8_t result= s->buffer[ index>>3 ];
673 #ifdef ALT_BITSTREAM_READER_LE
674 result>>= (index&0x07);
675 result&= 1;
676 #else
677 result<<= (index&0x07);
678 result>>= 8 - 1;
679 #endif
680 index++;
681 s->index= index;
682
683 return result;
684 #else
685 return get_bits(s, 1);
686 #endif
687 }
688
689 static inline unsigned int show_bits1(GetBitContext *s){
690 return show_bits(s, 1);
691 }
692
693 static inline void skip_bits1(GetBitContext *s){
694 skip_bits(s, 1);
695 }
696
697 /**
698 * reads 0-32 bits.
699 */
700 static inline unsigned int get_bits_long(GetBitContext *s, int n){
701 if(n<=17) return get_bits(s, n);
702 else{
703 #ifdef ALT_BITSTREAM_READER_LE
704 int ret= get_bits(s, 16);
705 return ret | (get_bits(s, n-16) << 16);
706 #else
707 int ret= get_bits(s, 16) << (n-16);
708 return ret | get_bits(s, n-16);
709 #endif
710 }
711 }
712
713 /**
714 * shows 0-32 bits.
715 */
716 static inline unsigned int show_bits_long(GetBitContext *s, int n){
717 if(n<=17) return show_bits(s, n);
718 else{
719 GetBitContext gb= *s;
720 int ret= get_bits_long(s, n);
721 *s= gb;
722 return ret;
723 }
724 }
725
726 static inline int check_marker(GetBitContext *s, const char *msg)
727 {
728 int bit= get_bits1(s);
729 if(!bit)
730 av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
731
732 return bit;
733 }
734
735 /**
736 * init GetBitContext.
737 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
738 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
739 * @param bit_size the size of the buffer in bits
740 */
741 static inline void init_get_bits(GetBitContext *s,
742 const uint8_t *buffer, int bit_size)
743 {
744 int buffer_size= (bit_size+7)>>3;
745 if(buffer_size < 0 || bit_size < 0) {
746 buffer_size = bit_size = 0;
747 buffer = NULL;
748 }
749
750 s->buffer= buffer;
751 s->size_in_bits= bit_size;
752 s->buffer_end= buffer + buffer_size;
753 #ifdef ALT_BITSTREAM_READER
754 s->index=0;
755 #elif defined LIBMPEG2_BITSTREAM_READER
756 s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
757 s->bit_count = 16 + 8*((intptr_t)buffer&1);
758 skip_bits_long(s, 0);
759 #elif defined A32_BITSTREAM_READER
760 s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
761 s->bit_count = 32 + 8*((intptr_t)buffer&3);
762 skip_bits_long(s, 0);
763 #endif
764 }
765
766 static inline void align_get_bits(GetBitContext *s)
767 {
768 int n= (-get_bits_count(s)) & 7;
769 if(n) skip_bits(s, n);
770 }
771
772 #define init_vlc(vlc, nb_bits, nb_codes,\
773 bits, bits_wrap, bits_size,\
774 codes, codes_wrap, codes_size,\
775 flags)\
776 init_vlc_sparse(vlc, nb_bits, nb_codes,\
777 bits, bits_wrap, bits_size,\
778 codes, codes_wrap, codes_size,\
779 NULL, 0, 0, flags)
780
781 int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
782 const void *bits, int bits_wrap, int bits_size,
783 const void *codes, int codes_wrap, int codes_size,
784 const void *symbols, int symbols_wrap, int symbols_size,
785 int flags);
786 #define INIT_VLC_USE_STATIC 1 ///< VERY strongly deprecated and forbidden
787 #define INIT_VLC_LE 2
788 #define INIT_VLC_USE_NEW_STATIC 4
789 void free_vlc(VLC *vlc);
790
791 #define INIT_VLC_STATIC(vlc, bits, a,b,c,d,e,f,g, static_size)\
792 {\
793 static VLC_TYPE table[static_size][2];\
794 (vlc)->table= table;\
795 (vlc)->table_allocated= static_size;\
796 init_vlc(vlc, bits, a,b,c,d,e,f,g, INIT_VLC_USE_NEW_STATIC);\
797 }
798
799
800 /**
801 *
802 * if the vlc code is invalid and max_depth=1 than no bits will be removed
803 * if the vlc code is invalid and max_depth>1 than the number of bits removed
804 * is undefined
805 */
806 #define GET_VLC(code, name, gb, table, bits, max_depth)\
807 {\
808 int n, index, nb_bits;\
809 \
810 index= SHOW_UBITS(name, gb, bits);\
811 code = table[index][0];\
812 n = table[index][1];\
813 \
814 if(max_depth > 1 && n < 0){\
815 LAST_SKIP_BITS(name, gb, bits)\
816 UPDATE_CACHE(name, gb)\
817 \
818 nb_bits = -n;\
819 \
820 index= SHOW_UBITS(name, gb, nb_bits) + code;\
821 code = table[index][0];\
822 n = table[index][1];\
823 if(max_depth > 2 && n < 0){\
824 LAST_SKIP_BITS(name, gb, nb_bits)\
825 UPDATE_CACHE(name, gb)\
826 \
827 nb_bits = -n;\
828 \
829 index= SHOW_UBITS(name, gb, nb_bits) + code;\
830 code = table[index][0];\
831 n = table[index][1];\
832 }\
833 }\
834 SKIP_BITS(name, gb, n)\
835 }
836
837 #define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
838 {\
839 int n, index, nb_bits;\
840 \
841 index= SHOW_UBITS(name, gb, bits);\
842 level = table[index].level;\
843 n = table[index].len;\
844 \
845 if(max_depth > 1 && n < 0){\
846 SKIP_BITS(name, gb, bits)\
847 if(need_update){\
848 UPDATE_CACHE(name, gb)\
849 }\
850 \
851 nb_bits = -n;\
852 \
853 index= SHOW_UBITS(name, gb, nb_bits) + level;\
854 level = table[index].level;\
855 n = table[index].len;\
856 }\
857 run= table[index].run;\
858 SKIP_BITS(name, gb, n)\
859 }
860
861
862 /**
863 * parses a vlc code, faster then get_vlc()
864 * @param bits is the number of bits which will be read at once, must be
865 * identical to nb_bits in init_vlc()
866 * @param max_depth is the number of times bits bits must be read to completely
867 * read the longest vlc code
868 * = (max_vlc_length + bits - 1) / bits
869 */
870 static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
871 int bits, int max_depth)
872 {
873 int code;
874
875 OPEN_READER(re, s)
876 UPDATE_CACHE(re, s)
877
878 GET_VLC(code, re, s, table, bits, max_depth)
879
880 CLOSE_READER(re, s)
881 return code;
882 }
883
884 //#define TRACE
885
886 #ifdef TRACE
887 static inline void print_bin(int bits, int n){
888 int i;
889
890 for(i=n-1; i>=0; i--){
891 av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
892 }
893 for(i=n; i<24; i++)
894 av_log(NULL, AV_LOG_DEBUG, " ");
895 }
896
897 static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
898 int r= get_bits(s, n);
899
900 print_bin(r, n);
901 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);
902 return r;
903 }
904 static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
905 int show= show_bits(s, 24);
906 int pos= get_bits_count(s);
907 int r= get_vlc2(s, table, bits, max_depth);
908 int len= get_bits_count(s) - pos;
909 int bits2= show>>(24-len);
910
911 print_bin(bits2, len);
912
913 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
914 return r;
915 }
916 static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
917 int show= show_bits(s, n);
918 int r= get_xbits(s, n);
919
920 print_bin(show, n);
921 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);
922 return r;
923 }
924
925 #define get_bits(s, n) get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
926 #define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
927 #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
928 #define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
929 #define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
930
931 #define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
932
933 #else //TRACE
934 #define tprintf(p, ...) {}
935 #endif
936
937 static inline int decode012(GetBitContext *gb){
938 int n;
939 n = get_bits1(gb);
940 if (n == 0)
941 return 0;
942 else
943 return get_bits1(gb) + 1;
944 }
945
946 static inline int decode210(GetBitContext *gb){
947 if (get_bits1(gb))
948 return 0;
949 else
950 return 2 - get_bits1(gb);
951 }
952
953 #endif /* AVCODEC_BITSTREAM_H */