FFmpeg  3.4.9
get_bits.h
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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
23  * bitstream reader API header.
24  */
25 
26 #ifndef AVCODEC_GET_BITS_H
27 #define AVCODEC_GET_BITS_H
28 
29 #include <stdint.h>
30 
31 #include "libavutil/common.h"
32 #include "libavutil/intreadwrite.h"
33 #include "libavutil/log.h"
34 #include "libavutil/avassert.h"
35 #include "avcodec.h"
36 #include "mathops.h"
37 #include "vlc.h"
38 
39 /*
40  * Safe bitstream reading:
41  * optionally, the get_bits API can check to ensure that we
42  * don't read past input buffer boundaries. This is protected
43  * with CONFIG_SAFE_BITSTREAM_READER at the global level, and
44  * then below that with UNCHECKED_BITSTREAM_READER at the per-
45  * decoder level. This means that decoders that check internally
46  * can "#define UNCHECKED_BITSTREAM_READER 1" to disable
47  * overread checks.
48  * Boundary checking causes a minor performance penalty so for
49  * applications that won't want/need this, it can be disabled
50  * globally using "#define CONFIG_SAFE_BITSTREAM_READER 0".
51  */
52 #ifndef UNCHECKED_BITSTREAM_READER
53 #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
54 #endif
55 
56 typedef struct GetBitContext {
58  int index;
62 
63 /* Bitstream reader API docs:
64  * name
65  * arbitrary name which is used as prefix for the internal variables
66  *
67  * gb
68  * getbitcontext
69  *
70  * OPEN_READER(name, gb)
71  * load gb into local variables
72  *
73  * CLOSE_READER(name, gb)
74  * store local vars in gb
75  *
76  * UPDATE_CACHE(name, gb)
77  * Refill the internal cache from the bitstream.
78  * After this call at least MIN_CACHE_BITS will be available.
79  *
80  * GET_CACHE(name, gb)
81  * Will output the contents of the internal cache,
82  * next bit is MSB of 32 or 64 bits (FIXME 64 bits).
83  *
84  * SHOW_UBITS(name, gb, num)
85  * Will return the next num bits.
86  *
87  * SHOW_SBITS(name, gb, num)
88  * Will return the next num bits and do sign extension.
89  *
90  * SKIP_BITS(name, gb, num)
91  * Will skip over the next num bits.
92  * Note, this is equivalent to SKIP_CACHE; SKIP_COUNTER.
93  *
94  * SKIP_CACHE(name, gb, num)
95  * Will remove the next num bits from the cache (note SKIP_COUNTER
96  * MUST be called before UPDATE_CACHE / CLOSE_READER).
97  *
98  * SKIP_COUNTER(name, gb, num)
99  * Will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS).
100  *
101  * LAST_SKIP_BITS(name, gb, num)
102  * Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER.
103  *
104  * BITS_LEFT(name, gb)
105  * Return the number of bits left
106  *
107  * For examples see get_bits, show_bits, skip_bits, get_vlc.
108  */
109 
110 #ifdef LONG_BITSTREAM_READER
111 # define MIN_CACHE_BITS 32
112 #else
113 # define MIN_CACHE_BITS 25
114 #endif
115 
116 #define OPEN_READER_NOSIZE(name, gb) \
117  unsigned int name ## _index = (gb)->index; \
118  unsigned int av_unused name ## _cache
119 
120 #if UNCHECKED_BITSTREAM_READER
121 #define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb)
122 
123 #define BITS_AVAILABLE(name, gb) 1
124 #else
125 #define OPEN_READER(name, gb) \
126  OPEN_READER_NOSIZE(name, gb); \
127  unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8
128 
129 #define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8
130 #endif
131 
132 #define CLOSE_READER(name, gb) (gb)->index = name ## _index
133 
134 # ifdef LONG_BITSTREAM_READER
135 
136 # define UPDATE_CACHE_LE(name, gb) name ## _cache = \
137  AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)
138 
139 # define UPDATE_CACHE_BE(name, gb) name ## _cache = \
140  AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7))
141 
142 #else
143 
144 # define UPDATE_CACHE_LE(name, gb) name ## _cache = \
145  AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)
146 
147 # define UPDATE_CACHE_BE(name, gb) name ## _cache = \
148  AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7)
149 
150 #endif
151 
152 
153 #ifdef BITSTREAM_READER_LE
154 
155 # define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb)
156 
157 # define SKIP_CACHE(name, gb, num) name ## _cache >>= (num)
158 
159 #else
160 
161 # define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb)
162 
163 # define SKIP_CACHE(name, gb, num) name ## _cache <<= (num)
164 
165 #endif
166 
167 #if UNCHECKED_BITSTREAM_READER
168 # define SKIP_COUNTER(name, gb, num) name ## _index += (num)
169 #else
170 # define SKIP_COUNTER(name, gb, num) \
171  name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num))
172 #endif
173 
174 #define BITS_LEFT(name, gb) ((int)((gb)->size_in_bits - name ## _index))
175 
176 #define SKIP_BITS(name, gb, num) \
177  do { \
178  SKIP_CACHE(name, gb, num); \
179  SKIP_COUNTER(name, gb, num); \
180  } while (0)
181 
182 #define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
183 
184 #define SHOW_UBITS_LE(name, gb, num) zero_extend(name ## _cache, num)
185 #define SHOW_SBITS_LE(name, gb, num) sign_extend(name ## _cache, num)
186 
187 #define SHOW_UBITS_BE(name, gb, num) NEG_USR32(name ## _cache, num)
188 #define SHOW_SBITS_BE(name, gb, num) NEG_SSR32(name ## _cache, num)
189 
190 #ifdef BITSTREAM_READER_LE
191 # define SHOW_UBITS(name, gb, num) SHOW_UBITS_LE(name, gb, num)
192 # define SHOW_SBITS(name, gb, num) SHOW_SBITS_LE(name, gb, num)
193 #else
194 # define SHOW_UBITS(name, gb, num) SHOW_UBITS_BE(name, gb, num)
195 # define SHOW_SBITS(name, gb, num) SHOW_SBITS_BE(name, gb, num)
196 #endif
197 
198 #define GET_CACHE(name, gb) ((uint32_t) name ## _cache)
199 
200 static inline int get_bits_count(const GetBitContext *s)
201 {
202  return s->index;
203 }
204 
205 static inline void skip_bits_long(GetBitContext *s, int n)
206 {
207 #if UNCHECKED_BITSTREAM_READER
208  s->index += n;
209 #else
210  s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index);
211 #endif
212 }
213 
214 /**
215  * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
216  * if MSB not set it is negative
217  * @param n length in bits
218  */
219 static inline int get_xbits(GetBitContext *s, int n)
220 {
221  register int sign;
222  register int32_t cache;
223  OPEN_READER(re, s);
224  av_assert2(n>0 && n<=25);
225  UPDATE_CACHE(re, s);
226  cache = GET_CACHE(re, s);
227  sign = ~cache >> 31;
228  LAST_SKIP_BITS(re, s, n);
229  CLOSE_READER(re, s);
230  return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
231 }
232 
233 static inline int get_xbits_le(GetBitContext *s, int n)
234 {
235  register int sign;
236  register int32_t cache;
237  OPEN_READER(re, s);
238  av_assert2(n>0 && n<=25);
239  UPDATE_CACHE_LE(re, s);
240  cache = GET_CACHE(re, s);
241  sign = sign_extend(~cache, n) >> 31;
242  LAST_SKIP_BITS(re, s, n);
243  CLOSE_READER(re, s);
244  return (zero_extend(sign ^ cache, n) ^ sign) - sign;
245 }
246 
247 static inline int get_sbits(GetBitContext *s, int n)
248 {
249  register int tmp;
250  OPEN_READER(re, s);
251  av_assert2(n>0 && n<=25);
252  UPDATE_CACHE(re, s);
253  tmp = SHOW_SBITS(re, s, n);
254  LAST_SKIP_BITS(re, s, n);
255  CLOSE_READER(re, s);
256  return tmp;
257 }
258 
259 /**
260  * Read 1-25 bits.
261  */
262 static inline unsigned int get_bits(GetBitContext *s, int n)
263 {
264  register int tmp;
265  OPEN_READER(re, s);
266  av_assert2(n>0 && n<=25);
267  UPDATE_CACHE(re, s);
268  tmp = SHOW_UBITS(re, s, n);
269  LAST_SKIP_BITS(re, s, n);
270  CLOSE_READER(re, s);
271  return tmp;
272 }
273 
274 /**
275  * Read 0-25 bits.
276  */
278 {
279  return n ? get_bits(s, n) : 0;
280 }
281 
282 static inline unsigned int get_bits_le(GetBitContext *s, int n)
283 {
284  register int tmp;
285  OPEN_READER(re, s);
286  av_assert2(n>0 && n<=25);
287  UPDATE_CACHE_LE(re, s);
288  tmp = SHOW_UBITS_LE(re, s, n);
289  LAST_SKIP_BITS(re, s, n);
290  CLOSE_READER(re, s);
291  return tmp;
292 }
293 
294 /**
295  * Show 1-25 bits.
296  */
297 static inline unsigned int show_bits(GetBitContext *s, int n)
298 {
299  register int tmp;
301  av_assert2(n>0 && n<=25);
302  UPDATE_CACHE(re, s);
303  tmp = SHOW_UBITS(re, s, n);
304  return tmp;
305 }
306 
307 static inline void skip_bits(GetBitContext *s, int n)
308 {
309  OPEN_READER(re, s);
310  LAST_SKIP_BITS(re, s, n);
311  CLOSE_READER(re, s);
312 }
313 
314 static inline unsigned int get_bits1(GetBitContext *s)
315 {
316  unsigned int index = s->index;
317  uint8_t result = s->buffer[index >> 3];
318 #ifdef BITSTREAM_READER_LE
319  result >>= index & 7;
320  result &= 1;
321 #else
322  result <<= index & 7;
323  result >>= 8 - 1;
324 #endif
325 #if !UNCHECKED_BITSTREAM_READER
326  if (s->index < s->size_in_bits_plus8)
327 #endif
328  index++;
329  s->index = index;
330 
331  return result;
332 }
333 
334 static inline unsigned int show_bits1(GetBitContext *s)
335 {
336  return show_bits(s, 1);
337 }
338 
339 static inline void skip_bits1(GetBitContext *s)
340 {
341  skip_bits(s, 1);
342 }
343 
344 /**
345  * Read 0-32 bits.
346  */
347 static inline unsigned int get_bits_long(GetBitContext *s, int n)
348 {
349  av_assert2(n>=0 && n<=32);
350  if (!n) {
351  return 0;
352  } else if (n <= MIN_CACHE_BITS) {
353  return get_bits(s, n);
354  } else {
355 #ifdef BITSTREAM_READER_LE
356  unsigned ret = get_bits(s, 16);
357  return ret | (get_bits(s, n - 16) << 16);
358 #else
359  unsigned ret = get_bits(s, 16) << (n - 16);
360  return ret | get_bits(s, n - 16);
361 #endif
362  }
363 }
364 
365 /**
366  * Read 0-64 bits.
367  */
368 static inline uint64_t get_bits64(GetBitContext *s, int n)
369 {
370  if (n <= 32) {
371  return get_bits_long(s, n);
372  } else {
373 #ifdef BITSTREAM_READER_LE
374  uint64_t ret = get_bits_long(s, 32);
375  return ret | (uint64_t) get_bits_long(s, n - 32) << 32;
376 #else
377  uint64_t ret = (uint64_t) get_bits_long(s, n - 32) << 32;
378  return ret | get_bits_long(s, 32);
379 #endif
380  }
381 }
382 
383 /**
384  * Read 0-32 bits as a signed integer.
385  */
386 static inline int get_sbits_long(GetBitContext *s, int n)
387 {
388  // sign_extend(x, 0) is undefined
389  if (!n)
390  return 0;
391 
392  return sign_extend(get_bits_long(s, n), n);
393 }
394 
395 /**
396  * Show 0-32 bits.
397  */
398 static inline unsigned int show_bits_long(GetBitContext *s, int n)
399 {
400  if (n <= MIN_CACHE_BITS) {
401  return show_bits(s, n);
402  } else {
403  GetBitContext gb = *s;
404  return get_bits_long(&gb, n);
405  }
406 }
407 
408 static inline int check_marker(void *logctx, GetBitContext *s, const char *msg)
409 {
410  int bit = get_bits1(s);
411  if (!bit)
412  av_log(logctx, AV_LOG_INFO, "Marker bit missing at %d of %d %s\n",
413  get_bits_count(s) - 1, s->size_in_bits, msg);
414 
415  return bit;
416 }
417 
418 /**
419  * Initialize GetBitContext.
420  * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
421  * larger than the actual read bits because some optimized bitstream
422  * readers read 32 or 64 bit at once and could read over the end
423  * @param bit_size the size of the buffer in bits
424  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
425  */
426 static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
427  int bit_size)
428 {
429  int buffer_size;
430  int ret = 0;
431 
432  if (bit_size >= INT_MAX - FFMAX(7, AV_INPUT_BUFFER_PADDING_SIZE*8) || bit_size < 0 || !buffer) {
433  bit_size = 0;
434  buffer = NULL;
435  ret = AVERROR_INVALIDDATA;
436  }
437 
438  buffer_size = (bit_size + 7) >> 3;
439 
440  s->buffer = buffer;
441  s->size_in_bits = bit_size;
442  s->size_in_bits_plus8 = bit_size + 8;
443  s->buffer_end = buffer + buffer_size;
444  s->index = 0;
445 
446  return ret;
447 }
448 
449 /**
450  * Initialize GetBitContext.
451  * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
452  * larger than the actual read bits because some optimized bitstream
453  * readers read 32 or 64 bit at once and could read over the end
454  * @param byte_size the size of the buffer in bytes
455  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
456  */
457 static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer,
458  int byte_size)
459 {
460  if (byte_size > INT_MAX / 8 || byte_size < 0)
461  byte_size = -1;
462  return init_get_bits(s, buffer, byte_size * 8);
463 }
464 
465 static inline const uint8_t *align_get_bits(GetBitContext *s)
466 {
467  int n = -get_bits_count(s) & 7;
468  if (n)
469  skip_bits(s, n);
470  return s->buffer + (s->index >> 3);
471 }
472 
473 /**
474  * If the vlc code is invalid and max_depth=1, then no bits will be removed.
475  * If the vlc code is invalid and max_depth>1, then the number of bits removed
476  * is undefined.
477  */
478 #define GET_VLC(code, name, gb, table, bits, max_depth) \
479  do { \
480  int n, nb_bits; \
481  unsigned int index; \
482  \
483  index = SHOW_UBITS(name, gb, bits); \
484  code = table[index][0]; \
485  n = table[index][1]; \
486  \
487  if (max_depth > 1 && n < 0) { \
488  LAST_SKIP_BITS(name, gb, bits); \
489  UPDATE_CACHE(name, gb); \
490  \
491  nb_bits = -n; \
492  \
493  index = SHOW_UBITS(name, gb, nb_bits) + code; \
494  code = table[index][0]; \
495  n = table[index][1]; \
496  if (max_depth > 2 && n < 0) { \
497  LAST_SKIP_BITS(name, gb, nb_bits); \
498  UPDATE_CACHE(name, gb); \
499  \
500  nb_bits = -n; \
501  \
502  index = SHOW_UBITS(name, gb, nb_bits) + code; \
503  code = table[index][0]; \
504  n = table[index][1]; \
505  } \
506  } \
507  SKIP_BITS(name, gb, n); \
508  } while (0)
509 
510 #define GET_RL_VLC(level, run, name, gb, table, bits, \
511  max_depth, need_update) \
512  do { \
513  int n, nb_bits; \
514  unsigned int index; \
515  \
516  index = SHOW_UBITS(name, gb, bits); \
517  level = table[index].level; \
518  n = table[index].len; \
519  \
520  if (max_depth > 1 && n < 0) { \
521  SKIP_BITS(name, gb, bits); \
522  if (need_update) { \
523  UPDATE_CACHE(name, gb); \
524  } \
525  \
526  nb_bits = -n; \
527  \
528  index = SHOW_UBITS(name, gb, nb_bits) + level; \
529  level = table[index].level; \
530  n = table[index].len; \
531  if (max_depth > 2 && n < 0) { \
532  LAST_SKIP_BITS(name, gb, nb_bits); \
533  if (need_update) { \
534  UPDATE_CACHE(name, gb); \
535  } \
536  nb_bits = -n; \
537  \
538  index = SHOW_UBITS(name, gb, nb_bits) + level; \
539  level = table[index].level; \
540  n = table[index].len; \
541  } \
542  } \
543  run = table[index].run; \
544  SKIP_BITS(name, gb, n); \
545  } while (0)
546 
547 /**
548  * Parse a vlc code.
549  * @param bits is the number of bits which will be read at once, must be
550  * identical to nb_bits in init_vlc()
551  * @param max_depth is the number of times bits bits must be read to completely
552  * read the longest vlc code
553  * = (max_vlc_length + bits - 1) / bits
554  * @returns the code parsed or -1 if no vlc matches
555  */
557  int bits, int max_depth)
558 {
559  int code;
560 
561  OPEN_READER(re, s);
562  UPDATE_CACHE(re, s);
563 
564  GET_VLC(code, re, s, table, bits, max_depth);
565 
566  CLOSE_READER(re, s);
567 
568  return code;
569 }
570 
571 static inline int decode012(GetBitContext *gb)
572 {
573  int n;
574  n = get_bits1(gb);
575  if (n == 0)
576  return 0;
577  else
578  return get_bits1(gb) + 1;
579 }
580 
581 static inline int decode210(GetBitContext *gb)
582 {
583  if (get_bits1(gb))
584  return 0;
585  else
586  return 2 - get_bits1(gb);
587 }
588 
589 static inline int get_bits_left(GetBitContext *gb)
590 {
591  return gb->size_in_bits - get_bits_count(gb);
592 }
593 
594 static inline int skip_1stop_8data_bits(GetBitContext *gb)
595 {
596  if (get_bits_left(gb) <= 0)
597  return AVERROR_INVALIDDATA;
598 
599  while (get_bits1(gb)) {
600  skip_bits(gb, 8);
601  if (get_bits_left(gb) <= 0)
602  return AVERROR_INVALIDDATA;
603  }
604 
605  return 0;
606 }
607 
608 #endif /* AVCODEC_GET_BITS_H */
static int get_xbits_le(GetBitContext *s, int n)
Definition: get_bits.h:233
static unsigned int show_bits_long(GetBitContext *s, int n)
Show 0-32 bits.
Definition: get_bits.h:398
static unsigned int show_bits1(GetBitContext *s)
Definition: get_bits.h:334
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
float re
Definition: fft.c:82
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:262
static void skip_bits_long(GetBitContext *s, int n)
Definition: get_bits.h:205
static int check_marker(void *logctx, GetBitContext *s, const char *msg)
Definition: get_bits.h:408
const uint8_t * buffer
Definition: get_bits.h:57
static av_const unsigned zero_extend(unsigned val, unsigned bits)
Definition: mathops.h:139
static int get_sbits(GetBitContext *s, int n)
Definition: get_bits.h:247
static int get_sbits_long(GetBitContext *s, int n)
Read 0-32 bits as a signed integer.
Definition: get_bits.h:386
uint8_t bits
Definition: crc.c:296
uint8_t
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
Definition: avassert.h:64
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:200
#define SHOW_UBITS_LE(name, gb, num)
Definition: get_bits.h:184
#define av_log(a,...)
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:589
static uint64_t get_bits64(GetBitContext *s, int n)
Read 0-64 bits.
Definition: get_bits.h:368
#define UPDATE_CACHE(name, gb)
Definition: get_bits.h:161
static const struct endianess table[]
simple assert() macros that are a bit more flexible than ISO C assert().
#define CLOSE_READER(name, gb)
Definition: get_bits.h:132
#define FFMAX(a, b)
Definition: common.h:94
#define NEG_USR32(a, s)
Definition: mathops.h:166
int size_in_bits
Definition: get_bits.h:59
int32_t
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:297
#define LAST_SKIP_BITS(name, gb, num)
Definition: get_bits.h:182
static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE(*table)[2], int bits, int max_depth)
Parse a vlc code.
Definition: get_bits.h:556
int n
Definition: avisynth_c.h:684
#define GET_VLC(code, name, gb, table, bits, max_depth)
If the vlc code is invalid and max_depth=1, then no bits will be removed.
Definition: get_bits.h:478
#define SHOW_UBITS(name, gb, num)
Definition: get_bits.h:194
static int decode210(GetBitContext *gb)
Definition: get_bits.h:581
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
Libavcodec external API header.
int size_in_bits_plus8
Definition: get_bits.h:60
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:457
static int get_xbits(GetBitContext *s, int n)
Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
Definition: get_bits.h:219
#define OPEN_READER(name, gb)
Definition: get_bits.h:121
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:314
static void skip_bits1(GetBitContext *s)
Definition: get_bits.h:339
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:307
#define UPDATE_CACHE_LE(name, gb)
Definition: get_bits.h:144
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:426
#define GET_CACHE(name, gb)
Definition: get_bits.h:198
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:347
#define MIN_CACHE_BITS
Definition: get_bits.h:113
static av_const int sign_extend(int val, unsigned bits)
Definition: mathops.h:130
static unsigned int get_bits_le(GetBitContext *s, int n)
Definition: get_bits.h:282
#define SHOW_SBITS(name, gb, num)
Definition: get_bits.h:195
#define OPEN_READER_NOSIZE(name, gb)
Definition: get_bits.h:116
common internal and external API header
const uint8_t * buffer_end
Definition: get_bits.h:57
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:777
static int decode012(GetBitContext *gb)
Definition: get_bits.h:571
static const uint8_t * align_get_bits(GetBitContext *s)
Definition: get_bits.h:465
static int skip_1stop_8data_bits(GetBitContext *gb)
Definition: get_bits.h:594
#define av_always_inline
Definition: attributes.h:39
#define VLC_TYPE
Definition: vlc.h:24
static av_always_inline int get_bitsz(GetBitContext *s, int n)
Read 0-25 bits.
Definition: get_bits.h:277
static uint8_t tmp[11]
Definition: aes_ctr.c:26