yading@10: /*
yading@10:  * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * bitstream reader API header.
yading@10:  */
yading@10: 
yading@10: #ifndef AVCODEC_GET_BITS_H
yading@10: #define AVCODEC_GET_BITS_H
yading@10: 
yading@10: #include <stdint.h>
yading@10: 
yading@10: #include "libavutil/common.h"
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "libavutil/log.h"
yading@10: #include "libavutil/avassert.h"
yading@10: #include "mathops.h"
yading@10: 
yading@10: /*
yading@10:  * Safe bitstream reading:
yading@10:  * optionally, the get_bits API can check to ensure that we
yading@10:  * don't read past input buffer boundaries. This is protected
yading@10:  * with CONFIG_SAFE_BITSTREAM_READER at the global level, and
yading@10:  * then below that with UNCHECKED_BITSTREAM_READER at the per-
yading@10:  * decoder level. This means that decoders that check internally
yading@10:  * can "#define UNCHECKED_BITSTREAM_READER 1" to disable
yading@10:  * overread checks.
yading@10:  * Boundary checking causes a minor performance penalty so for
yading@10:  * applications that won't want/need this, it can be disabled
yading@10:  * globally using "#define CONFIG_SAFE_BITSTREAM_READER 0".
yading@10:  */
yading@10: #ifndef UNCHECKED_BITSTREAM_READER
yading@10: #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
yading@10: #endif
yading@10: 
yading@10: typedef struct GetBitContext {
yading@10:     const uint8_t *buffer, *buffer_end;
yading@10:     int index;
yading@10:     int size_in_bits;
yading@10:     int size_in_bits_plus8;
yading@10: } GetBitContext;
yading@10: 
yading@10: #define VLC_TYPE int16_t
yading@10: 
yading@10: typedef struct VLC {
yading@10:     int bits;
yading@10:     VLC_TYPE (*table)[2]; ///< code, bits
yading@10:     int table_size, table_allocated;
yading@10: } VLC;
yading@10: 
yading@10: typedef struct RL_VLC_ELEM {
yading@10:     int16_t level;
yading@10:     int8_t len;
yading@10:     uint8_t run;
yading@10: } RL_VLC_ELEM;
yading@10: 
yading@10: /* Bitstream reader API docs:
yading@10:  * name
yading@10:  *   arbitrary name which is used as prefix for the internal variables
yading@10:  *
yading@10:  * gb
yading@10:  *   getbitcontext
yading@10:  *
yading@10:  * OPEN_READER(name, gb)
yading@10:  *   load gb into local variables
yading@10:  *
yading@10:  * CLOSE_READER(name, gb)
yading@10:  *   store local vars in gb
yading@10:  *
yading@10:  * UPDATE_CACHE(name, gb)
yading@10:  *   Refill the internal cache from the bitstream.
yading@10:  *   After this call at least MIN_CACHE_BITS will be available.
yading@10:  *
yading@10:  * GET_CACHE(name, gb)
yading@10:  *   Will output the contents of the internal cache,
yading@10:  *   next bit is MSB of 32 or 64 bit (FIXME 64bit).
yading@10:  *
yading@10:  * SHOW_UBITS(name, gb, num)
yading@10:  *   Will return the next num bits.
yading@10:  *
yading@10:  * SHOW_SBITS(name, gb, num)
yading@10:  *   Will return the next num bits and do sign extension.
yading@10:  *
yading@10:  * SKIP_BITS(name, gb, num)
yading@10:  *   Will skip over the next num bits.
yading@10:  *   Note, this is equivalent to SKIP_CACHE; SKIP_COUNTER.
yading@10:  *
yading@10:  * SKIP_CACHE(name, gb, num)
yading@10:  *   Will remove the next num bits from the cache (note SKIP_COUNTER
yading@10:  *   MUST be called before UPDATE_CACHE / CLOSE_READER).
yading@10:  *
yading@10:  * SKIP_COUNTER(name, gb, num)
yading@10:  *   Will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS).
yading@10:  *
yading@10:  * LAST_SKIP_BITS(name, gb, num)
yading@10:  *   Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER.
yading@10:  *
yading@10:  * For examples see get_bits, show_bits, skip_bits, get_vlc.
yading@10:  */
yading@10: 
yading@10: #ifdef LONG_BITSTREAM_READER
yading@10: #   define MIN_CACHE_BITS 32
yading@10: #else
yading@10: #   define MIN_CACHE_BITS 25
yading@10: #endif
yading@10: 
yading@10: #if UNCHECKED_BITSTREAM_READER
yading@10: #define OPEN_READER(name, gb)                   \
yading@10:     unsigned int name ## _index = (gb)->index;  \
yading@10:     unsigned int av_unused name ## _cache
yading@10: 
yading@10: #define HAVE_BITS_REMAINING(name, gb) 1
yading@10: #else
yading@10: #define OPEN_READER(name, gb)                   \
yading@10:     unsigned int name ## _index = (gb)->index;  \
yading@10:     unsigned int av_unused name ## _cache = 0;  \
yading@10:     unsigned int av_unused name ## _size_plus8 = (gb)->size_in_bits_plus8
yading@10: 
yading@10: #define HAVE_BITS_REMAINING(name, gb) name ## _index < name ## _size_plus8
yading@10: #endif
yading@10: 
yading@10: #define CLOSE_READER(name, gb) (gb)->index = name ## _index
yading@10: 
yading@10: #ifdef BITSTREAM_READER_LE
yading@10: 
yading@10: # ifdef LONG_BITSTREAM_READER
yading@10: #   define UPDATE_CACHE(name, gb) name ## _cache = \
yading@10:         AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)
yading@10: # else
yading@10: #   define UPDATE_CACHE(name, gb) name ## _cache = \
yading@10:         AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)
yading@10: # endif
yading@10: 
yading@10: # define SKIP_CACHE(name, gb, num) name ## _cache >>= (num)
yading@10: 
yading@10: #else
yading@10: 
yading@10: # ifdef LONG_BITSTREAM_READER
yading@10: #   define UPDATE_CACHE(name, gb) name ## _cache = \
yading@10:         AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7))
yading@10: # else
yading@10: #   define UPDATE_CACHE(name, gb) name ## _cache = \
yading@10:         AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7)
yading@10: # endif
yading@10: 
yading@10: # define SKIP_CACHE(name, gb, num) name ## _cache <<= (num)
yading@10: 
yading@10: #endif
yading@10: 
yading@10: #if UNCHECKED_BITSTREAM_READER
yading@10: #   define SKIP_COUNTER(name, gb, num) name ## _index += (num)
yading@10: #else
yading@10: #   define SKIP_COUNTER(name, gb, num) \
yading@10:     name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num))
yading@10: #endif
yading@10: 
yading@10: #define SKIP_BITS(name, gb, num)                \
yading@10:     do {                                        \
yading@10:         SKIP_CACHE(name, gb, num);              \
yading@10:         SKIP_COUNTER(name, gb, num);            \
yading@10:     } while (0)
yading@10: 
yading@10: #define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
yading@10: 
yading@10: #ifdef BITSTREAM_READER_LE
yading@10: #   define SHOW_UBITS(name, gb, num) zero_extend(name ## _cache, num)
yading@10: #   define SHOW_SBITS(name, gb, num) sign_extend(name ## _cache, num)
yading@10: #else
yading@10: #   define SHOW_UBITS(name, gb, num) NEG_USR32(name ## _cache, num)
yading@10: #   define SHOW_SBITS(name, gb, num) NEG_SSR32(name ## _cache, num)
yading@10: #endif
yading@10: 
yading@10: #define GET_CACHE(name, gb) ((uint32_t) name ## _cache)
yading@10: 
yading@10: static inline int get_bits_count(const GetBitContext *s)
yading@10: {
yading@10:     return s->index;
yading@10: }
yading@10: 
yading@10: static inline void skip_bits_long(GetBitContext *s, int n)
yading@10: {
yading@10: #if UNCHECKED_BITSTREAM_READER
yading@10:     s->index += n;
yading@10: #else
yading@10:     s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index);
yading@10: #endif
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
yading@10:  * if MSB not set it is negative
yading@10:  * @param n length in bits
yading@10:  */
yading@10: static inline int get_xbits(GetBitContext *s, int n)
yading@10: {
yading@10:     register int sign;
yading@10:     register int32_t cache;
yading@10:     OPEN_READER(re, s);
yading@10:     UPDATE_CACHE(re, s);
yading@10:     cache = GET_CACHE(re, s);
yading@10:     sign  = ~cache >> 31;
yading@10:     LAST_SKIP_BITS(re, s, n);
yading@10:     CLOSE_READER(re, s);
yading@10:     return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
yading@10: }
yading@10: 
yading@10: static inline int get_sbits(GetBitContext *s, int n)
yading@10: {
yading@10:     register int tmp;
yading@10:     OPEN_READER(re, s);
yading@10:     av_assert2(n>0 && n<=25);
yading@10:     UPDATE_CACHE(re, s);
yading@10:     tmp = SHOW_SBITS(re, s, n);
yading@10:     LAST_SKIP_BITS(re, s, n);
yading@10:     CLOSE_READER(re, s);
yading@10:     return tmp;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Read 1-25 bits.
yading@10:  */
yading@10: static inline unsigned int get_bits(GetBitContext *s, int n)
yading@10: {
yading@10:     register int tmp;
yading@10:     OPEN_READER(re, s);
yading@10:     av_assert2(n>0 && n<=25);
yading@10:     UPDATE_CACHE(re, s);
yading@10:     tmp = SHOW_UBITS(re, s, n);
yading@10:     LAST_SKIP_BITS(re, s, n);
yading@10:     CLOSE_READER(re, s);
yading@10:     return tmp;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Show 1-25 bits.
yading@10:  */
yading@10: static inline unsigned int show_bits(GetBitContext *s, int n)
yading@10: {
yading@10:     register int tmp;
yading@10:     OPEN_READER(re, s);
yading@10:     av_assert2(n>0 && n<=25);
yading@10:     UPDATE_CACHE(re, s);
yading@10:     tmp = SHOW_UBITS(re, s, n);
yading@10:     return tmp;
yading@10: }
yading@10: 
yading@10: static inline void skip_bits(GetBitContext *s, int n)
yading@10: {
yading@10:     OPEN_READER(re, s);
yading@10:     UPDATE_CACHE(re, s);
yading@10:     LAST_SKIP_BITS(re, s, n);
yading@10:     CLOSE_READER(re, s);
yading@10: }
yading@10: 
yading@10: static inline unsigned int get_bits1(GetBitContext *s)
yading@10: {
yading@10:     unsigned int index = s->index;
yading@10:     uint8_t result     = s->buffer[index >> 3];
yading@10: #ifdef BITSTREAM_READER_LE
yading@10:     result >>= index & 7;
yading@10:     result  &= 1;
yading@10: #else
yading@10:     result <<= index & 7;
yading@10:     result >>= 8 - 1;
yading@10: #endif
yading@10: #if !UNCHECKED_BITSTREAM_READER
yading@10:     if (s->index < s->size_in_bits_plus8)
yading@10: #endif
yading@10:         index++;
yading@10:     s->index = index;
yading@10: 
yading@10:     return result;
yading@10: }
yading@10: 
yading@10: static inline unsigned int show_bits1(GetBitContext *s)
yading@10: {
yading@10:     return show_bits(s, 1);
yading@10: }
yading@10: 
yading@10: static inline void skip_bits1(GetBitContext *s)
yading@10: {
yading@10:     skip_bits(s, 1);
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Read 0-32 bits.
yading@10:  */
yading@10: static inline unsigned int get_bits_long(GetBitContext *s, int n)
yading@10: {
yading@10:     if (!n) {
yading@10:         return 0;
yading@10:     } else if (n <= MIN_CACHE_BITS) {
yading@10:         return get_bits(s, n);
yading@10:     } else {
yading@10: #ifdef BITSTREAM_READER_LE
yading@10:         unsigned ret = get_bits(s, 16);
yading@10:         return ret | (get_bits(s, n - 16) << 16);
yading@10: #else
yading@10:         unsigned ret = get_bits(s, 16) << (n - 16);
yading@10:         return ret | get_bits(s, n - 16);
yading@10: #endif
yading@10:     }
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Read 0-64 bits.
yading@10:  */
yading@10: static inline uint64_t get_bits64(GetBitContext *s, int n)
yading@10: {
yading@10:     if (n <= 32) {
yading@10:         return get_bits_long(s, n);
yading@10:     } else {
yading@10: #ifdef BITSTREAM_READER_LE
yading@10:         uint64_t ret = get_bits_long(s, 32);
yading@10:         return ret | (uint64_t) get_bits_long(s, n - 32) << 32;
yading@10: #else
yading@10:         uint64_t ret = (uint64_t) get_bits_long(s, n - 32) << 32;
yading@10:         return ret | get_bits_long(s, 32);
yading@10: #endif
yading@10:     }
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Read 0-32 bits as a signed integer.
yading@10:  */
yading@10: static inline int get_sbits_long(GetBitContext *s, int n)
yading@10: {
yading@10:     return sign_extend(get_bits_long(s, n), n);
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Show 0-32 bits.
yading@10:  */
yading@10: static inline unsigned int show_bits_long(GetBitContext *s, int n)
yading@10: {
yading@10:     if (n <= MIN_CACHE_BITS) {
yading@10:         return show_bits(s, n);
yading@10:     } else {
yading@10:         GetBitContext gb = *s;
yading@10:         return get_bits_long(&gb, n);
yading@10:     }
yading@10: }
yading@10: 
yading@10: static inline int check_marker(GetBitContext *s, const char *msg)
yading@10: {
yading@10:     int bit = get_bits1(s);
yading@10:     if (!bit)
yading@10:         av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
yading@10: 
yading@10:     return bit;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Initialize GetBitContext.
yading@10:  * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes
yading@10:  *        larger than the actual read bits because some optimized bitstream
yading@10:  *        readers read 32 or 64 bit at once and could read over the end
yading@10:  * @param bit_size the size of the buffer in bits
yading@10:  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
yading@10:  */
yading@10: static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
yading@10:                                 int bit_size)
yading@10: {
yading@10:     int buffer_size;
yading@10:     int ret = 0;
yading@10: 
yading@10:     if (bit_size >= INT_MAX - 7 || bit_size < 0 || !buffer) {
yading@10:         buffer_size = bit_size = 0;
yading@10:         buffer      = NULL;
yading@10:         ret         = AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     buffer_size = (bit_size + 7) >> 3;
yading@10: 
yading@10:     s->buffer             = buffer;
yading@10:     s->size_in_bits       = bit_size;
yading@10:     s->size_in_bits_plus8 = bit_size + 8;
yading@10:     s->buffer_end         = buffer + buffer_size;
yading@10:     s->index              = 0;
yading@10: 
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Initialize GetBitContext.
yading@10:  * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes
yading@10:  *        larger than the actual read bits because some optimized bitstream
yading@10:  *        readers read 32 or 64 bit at once and could read over the end
yading@10:  * @param byte_size the size of the buffer in bytes
yading@10:  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
yading@10:  */
yading@10: static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer,
yading@10:                                  int byte_size)
yading@10: {
yading@10:     if (byte_size > INT_MAX / 8 || byte_size < 0)
yading@10:         byte_size = -1;
yading@10:     return init_get_bits(s, buffer, byte_size * 8);
yading@10: }
yading@10: 
yading@10: static inline const uint8_t *align_get_bits(GetBitContext *s)
yading@10: {
yading@10:     int n = -get_bits_count(s) & 7;
yading@10:     if (n)
yading@10:         skip_bits(s, n);
yading@10:     return s->buffer + (s->index >> 3);
yading@10: }
yading@10: 
yading@10: #define init_vlc(vlc, nb_bits, nb_codes,                \
yading@10:                  bits, bits_wrap, bits_size,            \
yading@10:                  codes, codes_wrap, codes_size,         \
yading@10:                  flags)                                 \
yading@10:     ff_init_vlc_sparse(vlc, nb_bits, nb_codes,          \
yading@10:                        bits, bits_wrap, bits_size,      \
yading@10:                        codes, codes_wrap, codes_size,   \
yading@10:                        NULL, 0, 0, flags)
yading@10: 
yading@10: int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
yading@10:                        const void *bits, int bits_wrap, int bits_size,
yading@10:                        const void *codes, int codes_wrap, int codes_size,
yading@10:                        const void *symbols, int symbols_wrap, int symbols_size,
yading@10:                        int flags);
yading@10: void ff_free_vlc(VLC *vlc);
yading@10: 
yading@10: #define INIT_VLC_LE             2
yading@10: #define INIT_VLC_USE_NEW_STATIC 4
yading@10: 
yading@10: #define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size)       \
yading@10:     do {                                                                   \
yading@10:         static VLC_TYPE table[static_size][2];                             \
yading@10:         (vlc)->table           = table;                                    \
yading@10:         (vlc)->table_allocated = static_size;                              \
yading@10:         init_vlc(vlc, bits, a, b, c, d, e, f, g, INIT_VLC_USE_NEW_STATIC); \
yading@10:     } while (0)
yading@10: 
yading@10: /**
yading@10:  * If the vlc code is invalid and max_depth=1, then no bits will be removed.
yading@10:  * If the vlc code is invalid and max_depth>1, then the number of bits removed
yading@10:  * is undefined.
yading@10:  */
yading@10: #define GET_VLC(code, name, gb, table, bits, max_depth)         \
yading@10:     do {                                                        \
yading@10:         int n, nb_bits;                                         \
yading@10:         unsigned int index;                                     \
yading@10:                                                                 \
yading@10:         index = SHOW_UBITS(name, gb, bits);                     \
yading@10:         code  = table[index][0];                                \
yading@10:         n     = table[index][1];                                \
yading@10:                                                                 \
yading@10:         if (max_depth > 1 && n < 0) {                           \
yading@10:             LAST_SKIP_BITS(name, gb, bits);                     \
yading@10:             UPDATE_CACHE(name, gb);                             \
yading@10:                                                                 \
yading@10:             nb_bits = -n;                                       \
yading@10:                                                                 \
yading@10:             index = SHOW_UBITS(name, gb, nb_bits) + code;       \
yading@10:             code  = table[index][0];                            \
yading@10:             n     = table[index][1];                            \
yading@10:             if (max_depth > 2 && n < 0) {                       \
yading@10:                 LAST_SKIP_BITS(name, gb, nb_bits);              \
yading@10:                 UPDATE_CACHE(name, gb);                         \
yading@10:                                                                 \
yading@10:                 nb_bits = -n;                                   \
yading@10:                                                                 \
yading@10:                 index = SHOW_UBITS(name, gb, nb_bits) + code;   \
yading@10:                 code  = table[index][0];                        \
yading@10:                 n     = table[index][1];                        \
yading@10:             }                                                   \
yading@10:         }                                                       \
yading@10:         SKIP_BITS(name, gb, n);                                 \
yading@10:     } while (0)
yading@10: 
yading@10: #define GET_RL_VLC(level, run, name, gb, table, bits,           \
yading@10:                    max_depth, need_update)                      \
yading@10:     do {                                                        \
yading@10:         int n, nb_bits;                                         \
yading@10:         unsigned int index;                                     \
yading@10:                                                                 \
yading@10:         index = SHOW_UBITS(name, gb, bits);                     \
yading@10:         level = table[index].level;                             \
yading@10:         n     = table[index].len;                               \
yading@10:                                                                 \
yading@10:         if (max_depth > 1 && n < 0) {                           \
yading@10:             SKIP_BITS(name, gb, bits);                          \
yading@10:             if (need_update) {                                  \
yading@10:                 UPDATE_CACHE(name, gb);                         \
yading@10:             }                                                   \
yading@10:                                                                 \
yading@10:             nb_bits = -n;                                       \
yading@10:                                                                 \
yading@10:             index = SHOW_UBITS(name, gb, nb_bits) + level;      \
yading@10:             level = table[index].level;                         \
yading@10:             n     = table[index].len;                           \
yading@10:         }                                                       \
yading@10:         run = table[index].run;                                 \
yading@10:         SKIP_BITS(name, gb, n);                                 \
yading@10:     } while (0)
yading@10: 
yading@10: /**
yading@10:  * Parse a vlc code.
yading@10:  * @param bits is the number of bits which will be read at once, must be
yading@10:  *             identical to nb_bits in init_vlc()
yading@10:  * @param max_depth is the number of times bits bits must be read to completely
yading@10:  *                  read the longest vlc code
yading@10:  *                  = (max_vlc_length + bits - 1) / bits
yading@10:  */
yading@10: static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
yading@10:                                      int bits, int max_depth)
yading@10: {
yading@10:     int code;
yading@10: 
yading@10:     OPEN_READER(re, s);
yading@10:     UPDATE_CACHE(re, s);
yading@10: 
yading@10:     GET_VLC(code, re, s, table, bits, max_depth);
yading@10: 
yading@10:     CLOSE_READER(re, s);
yading@10: 
yading@10:     return code;
yading@10: }
yading@10: 
yading@10: static inline int decode012(GetBitContext *gb)
yading@10: {
yading@10:     int n;
yading@10:     n = get_bits1(gb);
yading@10:     if (n == 0)
yading@10:         return 0;
yading@10:     else
yading@10:         return get_bits1(gb) + 1;
yading@10: }
yading@10: 
yading@10: static inline int decode210(GetBitContext *gb)
yading@10: {
yading@10:     if (get_bits1(gb))
yading@10:         return 0;
yading@10:     else
yading@10:         return 2 - get_bits1(gb);
yading@10: }
yading@10: 
yading@10: static inline int get_bits_left(GetBitContext *gb)
yading@10: {
yading@10:     return gb->size_in_bits - get_bits_count(gb);
yading@10: }
yading@10: 
yading@10: //#define TRACE
yading@10: 
yading@10: #ifdef TRACE
yading@10: static inline void print_bin(int bits, int n)
yading@10: {
yading@10:     int i;
yading@10: 
yading@10:     for (i = n - 1; i >= 0; i--)
yading@10:         av_log(NULL, AV_LOG_DEBUG, "%d", (bits >> i) & 1);
yading@10:     for (i = n; i < 24; i++)
yading@10:         av_log(NULL, AV_LOG_DEBUG, " ");
yading@10: }
yading@10: 
yading@10: static inline int get_bits_trace(GetBitContext *s, int n, const char *file,
yading@10:                                  const char *func, int line)
yading@10: {
yading@10:     int r = get_bits(s, n);
yading@10: 
yading@10:     print_bin(r, n);
yading@10:     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d bit @%5d in %s %s:%d\n",
yading@10:            r, n, r, get_bits_count(s) - n, file, func, line);
yading@10: 
yading@10:     return r;
yading@10: }
yading@10: 
yading@10: static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2],
yading@10:                                 int bits, int max_depth, const char *file,
yading@10:                                 const char *func, int line)
yading@10: {
yading@10:     int show  = show_bits(s, 24);
yading@10:     int pos   = get_bits_count(s);
yading@10:     int r     = get_vlc2(s, table, bits, max_depth);
yading@10:     int len   = get_bits_count(s) - pos;
yading@10:     int bits2 = show >> (24 - len);
yading@10: 
yading@10:     print_bin(bits2, len);
yading@10: 
yading@10:     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n",
yading@10:            bits2, len, r, pos, file, func, line);
yading@10: 
yading@10:     return r;
yading@10: }
yading@10: 
yading@10: static inline int get_xbits_trace(GetBitContext *s, int n, const char *file,
yading@10:                                   const char *func, int line)
yading@10: {
yading@10:     int show = show_bits(s, n);
yading@10:     int r    = get_xbits(s, n);
yading@10: 
yading@10:     print_bin(show, n);
yading@10:     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d xbt @%5d in %s %s:%d\n",
yading@10:            show, n, r, get_bits_count(s) - n, file, func, line);
yading@10: 
yading@10:     return r;
yading@10: }
yading@10: 
yading@10: #define get_bits(s, n)  get_bits_trace(s , n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
yading@10: #define get_bits1(s)    get_bits_trace(s,  1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
yading@10: #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
yading@10: 
yading@10: #define get_vlc(s, vlc)             get_vlc_trace(s, (vlc)->table, (vlc)->bits,   3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
yading@10: #define get_vlc2(s, tab, bits, max) get_vlc_trace(s,          tab,        bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
yading@10: 
yading@10: #define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
yading@10: 
yading@10: #else //TRACE
yading@10: #define tprintf(p, ...) { }
yading@10: #endif
yading@10: 
yading@10: #endif /* AVCODEC_GET_BITS_H */