Use AV_WL32/AV_WB32 in bitstream.h
[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 AV_WL32(s->buf_ptr, bit_buf);
202 } else
203 #endif
204 *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
205 s->buf_ptr+=4;
206 bit_buf = (bit_left==32)?0:value >> bit_left;
207 bit_left+=32;
208 }
209 bit_left-=n;
210 #else
211 if (n < bit_left) {
212 bit_buf = (bit_buf<<n) | value;
213 bit_left-=n;
214 } else {
215 bit_buf<<=bit_left;
216 bit_buf |= value >> (n - bit_left);
217 #if !HAVE_FAST_UNALIGNED
218 if (3 & (intptr_t) s->buf_ptr) {
219 AV_WB32(s->buf_ptr, bit_buf);
220 } else
221 #endif
222 *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
223 //printf("bitbuf = %08x\n", bit_buf);
224 s->buf_ptr+=4;
225 bit_left+=32 - n;
226 bit_buf = value;
227 }
228 #endif
229
230 s->bit_buf = bit_buf;
231 s->bit_left = bit_left;
232 }
233 #endif
234
235
236 #ifdef ALT_BITSTREAM_WRITER
237 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
238 {
239 # ifdef ALIGNED_BITSTREAM_WRITER
240 # if ARCH_X86
241 __asm__ volatile(
242 "movl %0, %%ecx \n\t"
243 "xorl %%eax, %%eax \n\t"
244 "shrdl %%cl, %1, %%eax \n\t"
245 "shrl %%cl, %1 \n\t"
246 "movl %0, %%ecx \n\t"
247 "shrl $3, %%ecx \n\t"
248 "andl $0xFFFFFFFC, %%ecx \n\t"
249 "bswapl %1 \n\t"
250 "orl %1, (%2, %%ecx) \n\t"
251 "bswapl %%eax \n\t"
252 "addl %3, %0 \n\t"
253 "movl %%eax, 4(%2, %%ecx) \n\t"
254 : "=&r" (s->index), "=&r" (value)
255 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
256 : "%eax", "%ecx"
257 );
258 # else
259 int index= s->index;
260 uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
261
262 value<<= 32-n;
263
264 ptr[0] |= be2me_32(value>>(index&31));
265 ptr[1] = be2me_32(value<<(32-(index&31)));
266 //if(n>24) printf("%d %d\n", n, value);
267 index+= n;
268 s->index= index;
269 # endif
270 # else //ALIGNED_BITSTREAM_WRITER
271 # if ARCH_X86
272 __asm__ volatile(
273 "movl $7, %%ecx \n\t"
274 "andl %0, %%ecx \n\t"
275 "addl %3, %%ecx \n\t"
276 "negl %%ecx \n\t"
277 "shll %%cl, %1 \n\t"
278 "bswapl %1 \n\t"
279 "movl %0, %%ecx \n\t"
280 "shrl $3, %%ecx \n\t"
281 "orl %1, (%%ecx, %2) \n\t"
282 "addl %3, %0 \n\t"
283 "movl $0, 4(%%ecx, %2) \n\t"
284 : "=&r" (s->index), "=&r" (value)
285 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
286 : "%ecx"
287 );
288 # else
289 int index= s->index;
290 uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
291
292 ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
293 ptr[1] = 0;
294 //if(n>24) printf("%d %d\n", n, value);
295 index+= n;
296 s->index= index;
297 # endif
298 # endif //!ALIGNED_BITSTREAM_WRITER
299 }
300 #endif
301
302 static inline void put_sbits(PutBitContext *pb, int bits, int32_t val)
303 {
304 assert(bits >= 0 && bits <= 31);
305
306 put_bits(pb, bits, val & ((1<<bits)-1));
307 }
308
309
310 static inline uint8_t* pbBufPtr(PutBitContext *s)
311 {
312 #ifdef ALT_BITSTREAM_WRITER
313 return s->buf + (s->index>>3);
314 #else
315 return s->buf_ptr;
316 #endif
317 }
318
319 /**
320 *
321 * PutBitContext must be flushed & aligned to a byte boundary before calling this.
322 */
323 static inline void skip_put_bytes(PutBitContext *s, int n){
324 assert((put_bits_count(s)&7)==0);
325 #ifdef ALT_BITSTREAM_WRITER
326 FIXME may need some cleaning of the buffer
327 s->index += n<<3;
328 #else
329 assert(s->bit_left==32);
330 s->buf_ptr += n;
331 #endif
332 }
333
334 /**
335 * Skips the given number of bits.
336 * Must only be used if the actual values in the bitstream do not matter.
337 */
338 static inline void skip_put_bits(PutBitContext *s, int n){
339 #ifdef ALT_BITSTREAM_WRITER
340 s->index += n;
341 #else
342 s->bit_left -= n;
343 s->buf_ptr-= s->bit_left>>5;
344 s->bit_left &= 31;
345 #endif
346 }
347
348 /**
349 * Changes the end of the buffer.
350 */
351 static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
352 s->buf_end= s->buf + size;
353 }
354
355 /* Bitstream reader API docs:
356 name
357 arbitrary name which is used as prefix for the internal variables
358
359 gb
360 getbitcontext
361
362 OPEN_READER(name, gb)
363 loads gb into local variables
364
365 CLOSE_READER(name, gb)
366 stores local vars in gb
367
368 UPDATE_CACHE(name, gb)
369 refills the internal cache from the bitstream
370 after this call at least MIN_CACHE_BITS will be available,
371
372 GET_CACHE(name, gb)
373 will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
374
375 SHOW_UBITS(name, gb, num)
376 will return the next num bits
377
378 SHOW_SBITS(name, gb, num)
379 will return the next num bits and do sign extension
380
381 SKIP_BITS(name, gb, num)
382 will skip over the next num bits
383 note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
384
385 SKIP_CACHE(name, gb, num)
386 will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
387
388 SKIP_COUNTER(name, gb, num)
389 will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
390
391 LAST_SKIP_CACHE(name, gb, num)
392 will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
393
394 LAST_SKIP_BITS(name, gb, num)
395 is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
396
397 for examples see get_bits, show_bits, skip_bits, get_vlc
398 */
399
400 #ifdef ALT_BITSTREAM_READER
401 # define MIN_CACHE_BITS 25
402
403 # define OPEN_READER(name, gb)\
404 int name##_index= (gb)->index;\
405 int name##_cache= 0;\
406
407 # define CLOSE_READER(name, gb)\
408 (gb)->index= name##_index;\
409
410 # ifdef ALT_BITSTREAM_READER_LE
411 # define UPDATE_CACHE(name, gb)\
412 name##_cache= AV_RL32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
413
414 # define SKIP_CACHE(name, gb, num)\
415 name##_cache >>= (num);
416 # else
417 # define UPDATE_CACHE(name, gb)\
418 name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
419
420 # define SKIP_CACHE(name, gb, num)\
421 name##_cache <<= (num);
422 # endif
423
424 // FIXME name?
425 # define SKIP_COUNTER(name, gb, num)\
426 name##_index += (num);\
427
428 # define SKIP_BITS(name, gb, num)\
429 {\
430 SKIP_CACHE(name, gb, num)\
431 SKIP_COUNTER(name, gb, num)\
432 }\
433
434 # define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
435 # define LAST_SKIP_CACHE(name, gb, num) ;
436
437 # ifdef ALT_BITSTREAM_READER_LE
438 # define SHOW_UBITS(name, gb, num)\
439 ((name##_cache) & (NEG_USR32(0xffffffff,num)))
440
441 # define SHOW_SBITS(name, gb, num)\
442 NEG_SSR32((name##_cache)<<(32-(num)), num)
443 # else
444 # define SHOW_UBITS(name, gb, num)\
445 NEG_USR32(name##_cache, num)
446
447 # define SHOW_SBITS(name, gb, num)\
448 NEG_SSR32(name##_cache, num)
449 # endif
450
451 # define GET_CACHE(name, gb)\
452 ((uint32_t)name##_cache)
453
454 static inline int get_bits_count(GetBitContext *s){
455 return s->index;
456 }
457
458 static inline void skip_bits_long(GetBitContext *s, int n){
459 s->index += n;
460 }
461
462 #elif defined LIBMPEG2_BITSTREAM_READER
463 //libmpeg2 like reader
464
465 # define MIN_CACHE_BITS 17
466
467 # define OPEN_READER(name, gb)\
468 int name##_bit_count=(gb)->bit_count;\
469 int name##_cache= (gb)->cache;\
470 uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
471
472 # define CLOSE_READER(name, gb)\
473 (gb)->bit_count= name##_bit_count;\
474 (gb)->cache= name##_cache;\
475 (gb)->buffer_ptr= name##_buffer_ptr;\
476
477 # define UPDATE_CACHE(name, gb)\
478 if(name##_bit_count >= 0){\
479 name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count; \
480 name##_buffer_ptr+=2;\
481 name##_bit_count-= 16;\
482 }\
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 static inline void skip_bits_long(GetBitContext *s, int n){
513 OPEN_READER(re, s)
514 re_bit_count += n;
515 re_buffer_ptr += 2*(re_bit_count>>4);
516 re_bit_count &= 15;
517 re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
518 UPDATE_CACHE(re, s)
519 CLOSE_READER(re, s)
520 }
521
522 #elif defined A32_BITSTREAM_READER
523
524 # define MIN_CACHE_BITS 32
525
526 # define OPEN_READER(name, gb)\
527 int name##_bit_count=(gb)->bit_count;\
528 uint32_t name##_cache0= (gb)->cache0;\
529 uint32_t name##_cache1= (gb)->cache1;\
530 uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
531
532 # define CLOSE_READER(name, gb)\
533 (gb)->bit_count= name##_bit_count;\
534 (gb)->cache0= name##_cache0;\
535 (gb)->cache1= name##_cache1;\
536 (gb)->buffer_ptr= name##_buffer_ptr;\
537
538 # define UPDATE_CACHE(name, gb)\
539 if(name##_bit_count > 0){\
540 const uint32_t next= be2me_32( *name##_buffer_ptr );\
541 name##_cache0 |= NEG_USR32(next,name##_bit_count);\
542 name##_cache1 |= next<<name##_bit_count;\
543 name##_buffer_ptr++;\
544 name##_bit_count-= 32;\
545 }\
546
547 #if ARCH_X86
548 # define SKIP_CACHE(name, gb, num)\
549 __asm__(\
550 "shldl %2, %1, %0 \n\t"\
551 "shll %2, %1 \n\t"\
552 : "+r" (name##_cache0), "+r" (name##_cache1)\
553 : "Ic" ((uint8_t)(num))\
554 );
555 #else
556 # define SKIP_CACHE(name, gb, num)\
557 name##_cache0 <<= (num);\
558 name##_cache0 |= NEG_USR32(name##_cache1,num);\
559 name##_cache1 <<= (num);
560 #endif
561
562 # define SKIP_COUNTER(name, gb, num)\
563 name##_bit_count += (num);\
564
565 # define SKIP_BITS(name, gb, num)\
566 {\
567 SKIP_CACHE(name, gb, num)\
568 SKIP_COUNTER(name, gb, num)\
569 }\
570
571 # define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
572 # define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
573
574 # define SHOW_UBITS(name, gb, num)\
575 NEG_USR32(name##_cache0, num)
576
577 # define SHOW_SBITS(name, gb, num)\
578 NEG_SSR32(name##_cache0, num)
579
580 # define GET_CACHE(name, gb)\
581 (name##_cache0)
582
583 static inline int get_bits_count(GetBitContext *s){
584 return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
585 }
586
587 static inline void skip_bits_long(GetBitContext *s, int n){
588 OPEN_READER(re, s)
589 re_bit_count += n;
590 re_buffer_ptr += re_bit_count>>5;
591 re_bit_count &= 31;
592 re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
593 re_cache1 = 0;
594 UPDATE_CACHE(re, s)
595 CLOSE_READER(re, s)
596 }
597
598 #endif
599
600 /**
601 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
602 * if MSB not set it is negative
603 * @param n length in bits
604 * @author BERO
605 */
606 static inline int get_xbits(GetBitContext *s, int n){
607 register int sign;
608 register int32_t cache;
609 OPEN_READER(re, s)
610 UPDATE_CACHE(re, s)
611 cache = GET_CACHE(re,s);
612 sign=(~cache)>>31;
613 LAST_SKIP_BITS(re, s, n)
614 CLOSE_READER(re, s)
615 return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
616 }
617
618 static inline int get_sbits(GetBitContext *s, int n){
619 register int tmp;
620 OPEN_READER(re, s)
621 UPDATE_CACHE(re, s)
622 tmp= SHOW_SBITS(re, s, n);
623 LAST_SKIP_BITS(re, s, n)
624 CLOSE_READER(re, s)
625 return tmp;
626 }
627
628 /**
629 * reads 1-17 bits.
630 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
631 */
632 static inline unsigned int get_bits(GetBitContext *s, int n){
633 register int tmp;
634 OPEN_READER(re, s)
635 UPDATE_CACHE(re, s)
636 tmp= SHOW_UBITS(re, s, n);
637 LAST_SKIP_BITS(re, s, n)
638 CLOSE_READER(re, s)
639 return tmp;
640 }
641
642 /**
643 * shows 1-17 bits.
644 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
645 */
646 static inline unsigned int show_bits(GetBitContext *s, int n){
647 register int tmp;
648 OPEN_READER(re, s)
649 UPDATE_CACHE(re, s)
650 tmp= SHOW_UBITS(re, s, n);
651 // CLOSE_READER(re, s)
652 return tmp;
653 }
654
655 static inline void skip_bits(GetBitContext *s, int n){
656 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
657 OPEN_READER(re, s)
658 UPDATE_CACHE(re, s)
659 LAST_SKIP_BITS(re, s, n)
660 CLOSE_READER(re, s)
661 }
662
663 static inline unsigned int get_bits1(GetBitContext *s){
664 #ifdef ALT_BITSTREAM_READER
665 int index= s->index;
666 uint8_t result= s->buffer[ index>>3 ];
667 #ifdef ALT_BITSTREAM_READER_LE
668 result>>= (index&0x07);
669 result&= 1;
670 #else
671 result<<= (index&0x07);
672 result>>= 8 - 1;
673 #endif
674 index++;
675 s->index= index;
676
677 return result;
678 #else
679 return get_bits(s, 1);
680 #endif
681 }
682
683 static inline unsigned int show_bits1(GetBitContext *s){
684 return show_bits(s, 1);
685 }
686
687 static inline void skip_bits1(GetBitContext *s){
688 skip_bits(s, 1);
689 }
690
691 /**
692 * reads 0-32 bits.
693 */
694 static inline unsigned int get_bits_long(GetBitContext *s, int n){
695 if(n<=17) return get_bits(s, n);
696 else{
697 #ifdef ALT_BITSTREAM_READER_LE
698 int ret= get_bits(s, 16);
699 return ret | (get_bits(s, n-16) << 16);
700 #else
701 int ret= get_bits(s, 16) << (n-16);
702 return ret | get_bits(s, n-16);
703 #endif
704 }
705 }
706
707 /**
708 * shows 0-32 bits.
709 */
710 static inline unsigned int show_bits_long(GetBitContext *s, int n){
711 if(n<=17) return show_bits(s, n);
712 else{
713 GetBitContext gb= *s;
714 int ret= get_bits_long(s, n);
715 *s= gb;
716 return ret;
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 */