9b388532205ece87cdda9e8ac31ffe6eb6c17a6c
[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 BITSTREAM_H
27 #define BITSTREAM_H
28
29 #include <stdint.h>
30 #include <stdlib.h>
31 #include <assert.h>
32 #include "common.h"
33 #include "bswap.h"
34 #include "intreadwrite.h"
35 #include "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 # ifdef ARCH_ARMV4L
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 #define LIBMPEG2_BITSTREAM_READER_HACK //add BERO
53
54 extern const uint8_t ff_reverse[256];
55
56 #if defined(ARCH_X86)
57 // avoid +32 for shift optimization (gcc should do that ...)
58 static inline int32_t NEG_SSR32( int32_t a, int8_t s){
59 asm ("sarl %1, %0\n\t"
60 : "+r" (a)
61 : "ic" ((uint8_t)(-s))
62 );
63 return a;
64 }
65 static inline uint32_t NEG_USR32(uint32_t a, int8_t s){
66 asm ("shrl %1, %0\n\t"
67 : "+r" (a)
68 : "ic" ((uint8_t)(-s))
69 );
70 return a;
71 }
72 #else
73 # define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
74 # define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
75 #endif
76
77 /* bit output */
78
79 /* buf and buf_end must be present and used by every alternative writer. */
80 typedef struct PutBitContext {
81 #ifdef ALT_BITSTREAM_WRITER
82 uint8_t *buf, *buf_end;
83 int index;
84 #else
85 uint32_t bit_buf;
86 int bit_left;
87 uint8_t *buf, *buf_ptr, *buf_end;
88 #endif
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->buf = buffer;
99 s->buf_end = s->buf + buffer_size;
100 #ifdef ALT_BITSTREAM_WRITER
101 s->index=0;
102 ((uint32_t*)(s->buf))[0]=0;
103 // memset(buffer, 0, buffer_size);
104 #else
105 s->buf_ptr = s->buf;
106 s->bit_left=32;
107 s->bit_buf=0;
108 #endif
109 }
110
111 /* return the number of bits output */
112 static inline int put_bits_count(PutBitContext *s)
113 {
114 #ifdef ALT_BITSTREAM_WRITER
115 return s->index;
116 #else
117 return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
118 #endif
119 }
120
121 /* pad the end of the output stream with zeros */
122 static inline void flush_put_bits(PutBitContext *s)
123 {
124 #ifdef ALT_BITSTREAM_WRITER
125 align_put_bits(s);
126 #else
127 s->bit_buf<<= s->bit_left;
128 while (s->bit_left < 32) {
129 /* XXX: should test end of buffer */
130 *s->buf_ptr++=s->bit_buf >> 24;
131 s->bit_buf<<=8;
132 s->bit_left+=8;
133 }
134 s->bit_left=32;
135 s->bit_buf=0;
136 #endif
137 }
138
139 void align_put_bits(PutBitContext *s);
140 void ff_put_string(PutBitContext * pbc, char *s, int put_zero);
141 void ff_copy_bits(PutBitContext *pb, uint8_t *src, int length);
142
143 /* bit input */
144 /* buffer, buffer_end and size_in_bits must be present and used by every reader */
145 typedef struct GetBitContext {
146 const uint8_t *buffer, *buffer_end;
147 #ifdef ALT_BITSTREAM_READER
148 int index;
149 #elif defined LIBMPEG2_BITSTREAM_READER
150 uint8_t *buffer_ptr;
151 uint32_t cache;
152 int bit_count;
153 #elif defined A32_BITSTREAM_READER
154 uint32_t *buffer_ptr;
155 uint32_t cache0;
156 uint32_t cache1;
157 int bit_count;
158 #endif
159 int size_in_bits;
160 } GetBitContext;
161
162 #define VLC_TYPE int16_t
163
164 typedef struct VLC {
165 int bits;
166 VLC_TYPE (*table)[2]; ///< code, bits
167 int table_size, table_allocated;
168 } VLC;
169
170 typedef struct RL_VLC_ELEM {
171 int16_t level;
172 int8_t len;
173 uint8_t run;
174 } RL_VLC_ELEM;
175
176 #if defined(ARCH_SPARC) || defined(ARCH_ARMV4L) || defined(ARCH_MIPS) || defined(ARCH_BFIN)
177 #define UNALIGNED_STORES_ARE_BAD
178 #endif
179
180 /* used to avoid misaligned exceptions on some archs (alpha, ...) */
181 #if defined(ARCH_X86)
182 # define unaligned16(a) (*(const uint16_t*)(a))
183 # define unaligned32(a) (*(const uint32_t*)(a))
184 # define unaligned64(a) (*(const uint64_t*)(a))
185 #else
186 # ifdef __GNUC__
187 # define unaligned(x) \
188 static inline uint##x##_t unaligned##x(const void *v) { \
189 struct Unaligned { \
190 uint##x##_t i; \
191 } __attribute__((packed)); \
192 \
193 return ((const struct Unaligned *) v)->i; \
194 }
195 # elif defined(__DECC)
196 # define unaligned(x) \
197 static inline uint##x##_t unaligned##x(const void *v) { \
198 return *(const __unaligned uint##x##_t *) v; \
199 }
200 # else
201 # define unaligned(x) \
202 static inline uint##x##_t unaligned##x(const void *v) { \
203 return *(const uint##x##_t *) v; \
204 }
205 # endif
206 unaligned(16)
207 unaligned(32)
208 unaligned(64)
209 #undef unaligned
210 #endif /* defined(ARCH_X86) */
211
212 #ifndef ALT_BITSTREAM_WRITER
213 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
214 {
215 unsigned int bit_buf;
216 int bit_left;
217
218 // printf("put_bits=%d %x\n", n, value);
219 assert(n == 32 || value < (1U << n));
220
221 bit_buf = s->bit_buf;
222 bit_left = s->bit_left;
223
224 // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
225 /* XXX: optimize */
226 if (n < bit_left) {
227 bit_buf = (bit_buf<<n) | value;
228 bit_left-=n;
229 } else {
230 bit_buf<<=bit_left;
231 bit_buf |= value >> (n - bit_left);
232 #ifdef UNALIGNED_STORES_ARE_BAD
233 if (3 & (intptr_t) s->buf_ptr) {
234 s->buf_ptr[0] = bit_buf >> 24;
235 s->buf_ptr[1] = bit_buf >> 16;
236 s->buf_ptr[2] = bit_buf >> 8;
237 s->buf_ptr[3] = bit_buf ;
238 } else
239 #endif
240 *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
241 //printf("bitbuf = %08x\n", bit_buf);
242 s->buf_ptr+=4;
243 bit_left+=32 - n;
244 bit_buf = value;
245 }
246
247 s->bit_buf = bit_buf;
248 s->bit_left = bit_left;
249 }
250 #endif
251
252
253 #ifdef ALT_BITSTREAM_WRITER
254 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
255 {
256 # ifdef ALIGNED_BITSTREAM_WRITER
257 # if defined(ARCH_X86)
258 asm volatile(
259 "movl %0, %%ecx \n\t"
260 "xorl %%eax, %%eax \n\t"
261 "shrdl %%cl, %1, %%eax \n\t"
262 "shrl %%cl, %1 \n\t"
263 "movl %0, %%ecx \n\t"
264 "shrl $3, %%ecx \n\t"
265 "andl $0xFFFFFFFC, %%ecx \n\t"
266 "bswapl %1 \n\t"
267 "orl %1, (%2, %%ecx) \n\t"
268 "bswapl %%eax \n\t"
269 "addl %3, %0 \n\t"
270 "movl %%eax, 4(%2, %%ecx) \n\t"
271 : "=&r" (s->index), "=&r" (value)
272 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
273 : "%eax", "%ecx"
274 );
275 # else
276 int index= s->index;
277 uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
278
279 value<<= 32-n;
280
281 ptr[0] |= be2me_32(value>>(index&31));
282 ptr[1] = be2me_32(value<<(32-(index&31)));
283 //if(n>24) printf("%d %d\n", n, value);
284 index+= n;
285 s->index= index;
286 # endif
287 # else //ALIGNED_BITSTREAM_WRITER
288 # if defined(ARCH_X86)
289 asm volatile(
290 "movl $7, %%ecx \n\t"
291 "andl %0, %%ecx \n\t"
292 "addl %3, %%ecx \n\t"
293 "negl %%ecx \n\t"
294 "shll %%cl, %1 \n\t"
295 "bswapl %1 \n\t"
296 "movl %0, %%ecx \n\t"
297 "shrl $3, %%ecx \n\t"
298 "orl %1, (%%ecx, %2) \n\t"
299 "addl %3, %0 \n\t"
300 "movl $0, 4(%%ecx, %2) \n\t"
301 : "=&r" (s->index), "=&r" (value)
302 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
303 : "%ecx"
304 );
305 # else
306 int index= s->index;
307 uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
308
309 ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
310 ptr[1] = 0;
311 //if(n>24) printf("%d %d\n", n, value);
312 index+= n;
313 s->index= index;
314 # endif
315 # endif //!ALIGNED_BITSTREAM_WRITER
316 }
317 #endif
318
319
320 static inline uint8_t* pbBufPtr(PutBitContext *s)
321 {
322 #ifdef ALT_BITSTREAM_WRITER
323 return s->buf + (s->index>>3);
324 #else
325 return s->buf_ptr;
326 #endif
327 }
328
329 /**
330 *
331 * PutBitContext must be flushed & aligned to a byte boundary before calling this.
332 */
333 static inline void skip_put_bytes(PutBitContext *s, int n){
334 assert((put_bits_count(s)&7)==0);
335 #ifdef ALT_BITSTREAM_WRITER
336 FIXME may need some cleaning of the buffer
337 s->index += n<<3;
338 #else
339 assert(s->bit_left==32);
340 s->buf_ptr += n;
341 #endif
342 }
343
344 /**
345 * Skips the given number of bits.
346 * Must only be used if the actual values in the bitstream do not matter.
347 */
348 static inline void skip_put_bits(PutBitContext *s, int n){
349 #ifdef ALT_BITSTREAM_WRITER
350 s->index += n;
351 #else
352 s->bit_left -= n;
353 s->buf_ptr-= s->bit_left>>5;
354 s->bit_left &= 31;
355 #endif
356 }
357
358 /**
359 * Changes the end of the buffer.
360 */
361 static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
362 s->buf_end= s->buf + size;
363 }
364
365 /* Bitstream reader API docs:
366 name
367 abritary name which is used as prefix for the internal variables
368
369 gb
370 getbitcontext
371
372 OPEN_READER(name, gb)
373 loads gb into local variables
374
375 CLOSE_READER(name, gb)
376 stores local vars in gb
377
378 UPDATE_CACHE(name, gb)
379 refills the internal cache from the bitstream
380 after this call at least MIN_CACHE_BITS will be available,
381
382 GET_CACHE(name, gb)
383 will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
384
385 SHOW_UBITS(name, gb, num)
386 will return the next num bits
387
388 SHOW_SBITS(name, gb, num)
389 will return the next num bits and do sign extension
390
391 SKIP_BITS(name, gb, num)
392 will skip over the next num bits
393 note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
394
395 SKIP_CACHE(name, gb, num)
396 will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
397
398 SKIP_COUNTER(name, gb, num)
399 will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
400
401 LAST_SKIP_CACHE(name, gb, num)
402 will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
403
404 LAST_SKIP_BITS(name, gb, num)
405 is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
406
407 for examples see get_bits, show_bits, skip_bits, get_vlc
408 */
409
410 #ifdef ALT_BITSTREAM_READER
411 # define MIN_CACHE_BITS 25
412
413 # define OPEN_READER(name, gb)\
414 int name##_index= (gb)->index;\
415 int name##_cache= 0;\
416
417 # define CLOSE_READER(name, gb)\
418 (gb)->index= name##_index;\
419
420 # ifdef ALT_BITSTREAM_READER_LE
421 # define UPDATE_CACHE(name, gb)\
422 name##_cache= AV_RL32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
423
424 # define SKIP_CACHE(name, gb, num)\
425 name##_cache >>= (num);
426 # else
427 # define UPDATE_CACHE(name, gb)\
428 name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
429
430 # define SKIP_CACHE(name, gb, num)\
431 name##_cache <<= (num);
432 # endif
433
434 // FIXME name?
435 # define SKIP_COUNTER(name, gb, num)\
436 name##_index += (num);\
437
438 # define SKIP_BITS(name, gb, num)\
439 {\
440 SKIP_CACHE(name, gb, num)\
441 SKIP_COUNTER(name, gb, num)\
442 }\
443
444 # define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
445 # define LAST_SKIP_CACHE(name, gb, num) ;
446
447 # ifdef ALT_BITSTREAM_READER_LE
448 # define SHOW_UBITS(name, gb, num)\
449 ((name##_cache) & (NEG_USR32(0xffffffff,num)))
450
451 # define SHOW_SBITS(name, gb, num)\
452 NEG_SSR32((name##_cache)<<(32-(num)), num)
453 # else
454 # define SHOW_UBITS(name, gb, num)\
455 NEG_USR32(name##_cache, num)
456
457 # define SHOW_SBITS(name, gb, num)\
458 NEG_SSR32(name##_cache, num)
459 # endif
460
461 # define GET_CACHE(name, gb)\
462 ((uint32_t)name##_cache)
463
464 static inline int get_bits_count(GetBitContext *s){
465 return s->index;
466 }
467
468 static inline void skip_bits_long(GetBitContext *s, int n){
469 s->index += n;
470 }
471
472 #elif defined LIBMPEG2_BITSTREAM_READER
473 //libmpeg2 like reader
474
475 # define MIN_CACHE_BITS 17
476
477 # define OPEN_READER(name, gb)\
478 int name##_bit_count=(gb)->bit_count;\
479 int name##_cache= (gb)->cache;\
480 uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
481
482 # define CLOSE_READER(name, gb)\
483 (gb)->bit_count= name##_bit_count;\
484 (gb)->cache= name##_cache;\
485 (gb)->buffer_ptr= name##_buffer_ptr;\
486
487 #ifdef LIBMPEG2_BITSTREAM_READER_HACK
488
489 # define UPDATE_CACHE(name, gb)\
490 if(name##_bit_count >= 0){\
491 name##_cache+= (int)be2me_16(*(uint16_t*)name##_buffer_ptr) << name##_bit_count;\
492 name##_buffer_ptr += 2;\
493 name##_bit_count-= 16;\
494 }\
495
496 #else
497
498 # define UPDATE_CACHE(name, gb)\
499 if(name##_bit_count >= 0){\
500 name##_cache+= ((name##_buffer_ptr[0]<<8) + name##_buffer_ptr[1]) << name##_bit_count;\
501 name##_buffer_ptr+=2;\
502 name##_bit_count-= 16;\
503 }\
504
505 #endif
506
507 # define SKIP_CACHE(name, gb, num)\
508 name##_cache <<= (num);\
509
510 # define SKIP_COUNTER(name, gb, num)\
511 name##_bit_count += (num);\
512
513 # define SKIP_BITS(name, gb, num)\
514 {\
515 SKIP_CACHE(name, gb, num)\
516 SKIP_COUNTER(name, gb, num)\
517 }\
518
519 # define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
520 # define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
521
522 # define SHOW_UBITS(name, gb, num)\
523 NEG_USR32(name##_cache, num)
524
525 # define SHOW_SBITS(name, gb, num)\
526 NEG_SSR32(name##_cache, num)
527
528 # define GET_CACHE(name, gb)\
529 ((uint32_t)name##_cache)
530
531 static inline int get_bits_count(GetBitContext *s){
532 return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
533 }
534
535 static inline void skip_bits_long(GetBitContext *s, int n){
536 OPEN_READER(re, s)
537 re_bit_count += n;
538 re_buffer_ptr += 2*(re_bit_count>>4);
539 re_bit_count &= 15;
540 re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
541 UPDATE_CACHE(re, s)
542 CLOSE_READER(re, s)
543 }
544
545 #elif defined A32_BITSTREAM_READER
546
547 # define MIN_CACHE_BITS 32
548
549 # define OPEN_READER(name, gb)\
550 int name##_bit_count=(gb)->bit_count;\
551 uint32_t name##_cache0= (gb)->cache0;\
552 uint32_t name##_cache1= (gb)->cache1;\
553 uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
554
555 # define CLOSE_READER(name, gb)\
556 (gb)->bit_count= name##_bit_count;\
557 (gb)->cache0= name##_cache0;\
558 (gb)->cache1= name##_cache1;\
559 (gb)->buffer_ptr= name##_buffer_ptr;\
560
561 # define UPDATE_CACHE(name, gb)\
562 if(name##_bit_count > 0){\
563 const uint32_t next= be2me_32( *name##_buffer_ptr );\
564 name##_cache0 |= NEG_USR32(next,name##_bit_count);\
565 name##_cache1 |= next<<name##_bit_count;\
566 name##_buffer_ptr++;\
567 name##_bit_count-= 32;\
568 }\
569
570 #if defined(ARCH_X86)
571 # define SKIP_CACHE(name, gb, num)\
572 asm(\
573 "shldl %2, %1, %0 \n\t"\
574 "shll %2, %1 \n\t"\
575 : "+r" (name##_cache0), "+r" (name##_cache1)\
576 : "Ic" ((uint8_t)(num))\
577 );
578 #else
579 # define SKIP_CACHE(name, gb, num)\
580 name##_cache0 <<= (num);\
581 name##_cache0 |= NEG_USR32(name##_cache1,num);\
582 name##_cache1 <<= (num);
583 #endif
584
585 # define SKIP_COUNTER(name, gb, num)\
586 name##_bit_count += (num);\
587
588 # define SKIP_BITS(name, gb, num)\
589 {\
590 SKIP_CACHE(name, gb, num)\
591 SKIP_COUNTER(name, gb, num)\
592 }\
593
594 # define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
595 # define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
596
597 # define SHOW_UBITS(name, gb, num)\
598 NEG_USR32(name##_cache0, num)
599
600 # define SHOW_SBITS(name, gb, num)\
601 NEG_SSR32(name##_cache0, num)
602
603 # define GET_CACHE(name, gb)\
604 (name##_cache0)
605
606 static inline int get_bits_count(GetBitContext *s){
607 return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
608 }
609
610 static inline void skip_bits_long(GetBitContext *s, int n){
611 OPEN_READER(re, s)
612 re_bit_count += n;
613 re_buffer_ptr += re_bit_count>>5;
614 re_bit_count &= 31;
615 re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
616 re_cache1 = 0;
617 UPDATE_CACHE(re, s)
618 CLOSE_READER(re, s)
619 }
620
621 #endif
622
623 /**
624 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
625 * if MSB not set it is negative
626 * @param n length in bits
627 * @author BERO
628 */
629 static inline int get_xbits(GetBitContext *s, int n){
630 register int sign;
631 register int32_t cache;
632 OPEN_READER(re, s)
633 UPDATE_CACHE(re, s)
634 cache = GET_CACHE(re,s);
635 sign=(~cache)>>31;
636 LAST_SKIP_BITS(re, s, n)
637 CLOSE_READER(re, s)
638 return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
639 }
640
641 static inline int get_sbits(GetBitContext *s, int n){
642 register int tmp;
643 OPEN_READER(re, s)
644 UPDATE_CACHE(re, s)
645 tmp= SHOW_SBITS(re, s, n);
646 LAST_SKIP_BITS(re, s, n)
647 CLOSE_READER(re, s)
648 return tmp;
649 }
650
651 /**
652 * reads 1-17 bits.
653 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
654 */
655 static inline unsigned int get_bits(GetBitContext *s, int n){
656 register int tmp;
657 OPEN_READER(re, s)
658 UPDATE_CACHE(re, s)
659 tmp= SHOW_UBITS(re, s, n);
660 LAST_SKIP_BITS(re, s, n)
661 CLOSE_READER(re, s)
662 return tmp;
663 }
664
665 /**
666 * shows 1-17 bits.
667 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
668 */
669 static inline unsigned int show_bits(GetBitContext *s, int n){
670 register int tmp;
671 OPEN_READER(re, s)
672 UPDATE_CACHE(re, s)
673 tmp= SHOW_UBITS(re, s, n);
674 // CLOSE_READER(re, s)
675 return tmp;
676 }
677
678 static inline void skip_bits(GetBitContext *s, int n){
679 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
680 OPEN_READER(re, s)
681 UPDATE_CACHE(re, s)
682 LAST_SKIP_BITS(re, s, n)
683 CLOSE_READER(re, s)
684 }
685
686 static inline unsigned int get_bits1(GetBitContext *s){
687 #ifdef ALT_BITSTREAM_READER
688 int index= s->index;
689 uint8_t result= s->buffer[ index>>3 ];
690 #ifdef ALT_BITSTREAM_READER_LE
691 result>>= (index&0x07);
692 result&= 1;
693 #else
694 result<<= (index&0x07);
695 result>>= 8 - 1;
696 #endif
697 index++;
698 s->index= index;
699
700 return result;
701 #else
702 return get_bits(s, 1);
703 #endif
704 }
705
706 static inline unsigned int show_bits1(GetBitContext *s){
707 return show_bits(s, 1);
708 }
709
710 static inline void skip_bits1(GetBitContext *s){
711 skip_bits(s, 1);
712 }
713
714 /**
715 * reads 0-32 bits.
716 */
717 static inline unsigned int get_bits_long(GetBitContext *s, int n){
718 if(n<=17) return get_bits(s, n);
719 else{
720 #ifdef ALT_BITSTREAM_READER_LE
721 int ret= get_bits(s, 16);
722 return ret | (get_bits(s, n-16) << 16);
723 #else
724 int ret= get_bits(s, 16) << (n-16);
725 return ret | get_bits(s, n-16);
726 #endif
727 }
728 }
729
730 /**
731 * shows 0-32 bits.
732 */
733 static inline unsigned int show_bits_long(GetBitContext *s, int n){
734 if(n<=17) return show_bits(s, n);
735 else{
736 GetBitContext gb= *s;
737 int ret= get_bits_long(s, n);
738 *s= gb;
739 return ret;
740 }
741 }
742
743 static inline int check_marker(GetBitContext *s, const char *msg)
744 {
745 int bit= get_bits1(s);
746 if(!bit)
747 av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
748
749 return bit;
750 }
751
752 /**
753 * init GetBitContext.
754 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
755 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
756 * @param bit_size the size of the buffer in bits
757 */
758 static inline void init_get_bits(GetBitContext *s,
759 const uint8_t *buffer, int bit_size)
760 {
761 int buffer_size= (bit_size+7)>>3;
762 if(buffer_size < 0 || bit_size < 0) {
763 buffer_size = bit_size = 0;
764 buffer = NULL;
765 }
766
767 s->buffer= buffer;
768 s->size_in_bits= bit_size;
769 s->buffer_end= buffer + buffer_size;
770 #ifdef ALT_BITSTREAM_READER
771 s->index=0;
772 #elif defined LIBMPEG2_BITSTREAM_READER
773 s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
774 s->bit_count = 16 + 8*((intptr_t)buffer&1);
775 skip_bits_long(s, 0);
776 #elif defined A32_BITSTREAM_READER
777 s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
778 s->bit_count = 32 + 8*((intptr_t)buffer&3);
779 skip_bits_long(s, 0);
780 #endif
781 }
782
783 static inline void align_get_bits(GetBitContext *s)
784 {
785 int n= (-get_bits_count(s)) & 7;
786 if(n) skip_bits(s, n);
787 }
788
789 #define init_vlc(vlc, nb_bits, nb_codes,\
790 bits, bits_wrap, bits_size,\
791 codes, codes_wrap, codes_size,\
792 flags)\
793 init_vlc_sparse(vlc, nb_bits, nb_codes,\
794 bits, bits_wrap, bits_size,\
795 codes, codes_wrap, codes_size,\
796 NULL, 0, 0, flags)
797
798 int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
799 const void *bits, int bits_wrap, int bits_size,
800 const void *codes, int codes_wrap, int codes_size,
801 const void *symbols, int symbols_wrap, int symbols_size,
802 int flags);
803 #define INIT_VLC_USE_STATIC 1
804 #define INIT_VLC_LE 2
805 void free_vlc(VLC *vlc);
806
807 /**
808 *
809 * if the vlc code is invalid and max_depth=1 than no bits will be removed
810 * if the vlc code is invalid and max_depth>1 than the number of bits removed
811 * is undefined
812 */
813 #define GET_VLC(code, name, gb, table, bits, max_depth)\
814 {\
815 int n, index, nb_bits;\
816 \
817 index= SHOW_UBITS(name, gb, bits);\
818 code = table[index][0];\
819 n = table[index][1];\
820 \
821 if(max_depth > 1 && n < 0){\
822 LAST_SKIP_BITS(name, gb, bits)\
823 UPDATE_CACHE(name, gb)\
824 \
825 nb_bits = -n;\
826 \
827 index= SHOW_UBITS(name, gb, nb_bits) + code;\
828 code = table[index][0];\
829 n = table[index][1];\
830 if(max_depth > 2 && n < 0){\
831 LAST_SKIP_BITS(name, gb, nb_bits)\
832 UPDATE_CACHE(name, gb)\
833 \
834 nb_bits = -n;\
835 \
836 index= SHOW_UBITS(name, gb, nb_bits) + code;\
837 code = table[index][0];\
838 n = table[index][1];\
839 }\
840 }\
841 SKIP_BITS(name, gb, n)\
842 }
843
844 #define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
845 {\
846 int n, index, nb_bits;\
847 \
848 index= SHOW_UBITS(name, gb, bits);\
849 level = table[index].level;\
850 n = table[index].len;\
851 \
852 if(max_depth > 1 && n < 0){\
853 SKIP_BITS(name, gb, bits)\
854 if(need_update){\
855 UPDATE_CACHE(name, gb)\
856 }\
857 \
858 nb_bits = -n;\
859 \
860 index= SHOW_UBITS(name, gb, nb_bits) + level;\
861 level = table[index].level;\
862 n = table[index].len;\
863 }\
864 run= table[index].run;\
865 SKIP_BITS(name, gb, n)\
866 }
867
868
869 /**
870 * parses a vlc code, faster then get_vlc()
871 * @param bits is the number of bits which will be read at once, must be
872 * identical to nb_bits in init_vlc()
873 * @param max_depth is the number of times bits bits must be read to completely
874 * read the longest vlc code
875 * = (max_vlc_length + bits - 1) / bits
876 */
877 static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
878 int bits, int max_depth)
879 {
880 int code;
881
882 OPEN_READER(re, s)
883 UPDATE_CACHE(re, s)
884
885 GET_VLC(code, re, s, table, bits, max_depth)
886
887 CLOSE_READER(re, s)
888 return code;
889 }
890
891 //#define TRACE
892
893 #ifdef TRACE
894 static inline void print_bin(int bits, int n){
895 int i;
896
897 for(i=n-1; i>=0; i--){
898 av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
899 }
900 for(i=n; i<24; i++)
901 av_log(NULL, AV_LOG_DEBUG, " ");
902 }
903
904 static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
905 int r= get_bits(s, n);
906
907 print_bin(r, n);
908 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);
909 return r;
910 }
911 static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
912 int show= show_bits(s, 24);
913 int pos= get_bits_count(s);
914 int r= get_vlc2(s, table, bits, max_depth);
915 int len= get_bits_count(s) - pos;
916 int bits2= show>>(24-len);
917
918 print_bin(bits2, len);
919
920 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
921 return r;
922 }
923 static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
924 int show= show_bits(s, n);
925 int r= get_xbits(s, n);
926
927 print_bin(show, n);
928 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);
929 return r;
930 }
931
932 #define get_bits(s, n) get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
933 #define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
934 #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
935 #define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
936 #define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
937
938 #define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
939
940 #else //TRACE
941 #define tprintf(p, ...) {}
942 #endif
943
944 static inline int decode012(GetBitContext *gb){
945 int n;
946 n = get_bits1(gb);
947 if (n == 0)
948 return 0;
949 else
950 return get_bits1(gb) + 1;
951 }
952
953 #endif /* BITSTREAM_H */