libavcodec/get_bits.h - nest-android-app/ffmpeg - Git at Google

 /*
  * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 /**
  * @file
  * bitstream reader API header.
  */

 #ifndef AVCODEC_GET_BITS_H
 #define AVCODEC_GET_BITS_H

 #include <stdint.h>

 #include "libavutil/common.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/log.h"
 #include "libavutil/avassert.h"
 #include "mathops.h"

 /*
  * Safe bitstream reading:
  * optionally, the get_bits API can check to ensure that we
  * don't read past input buffer boundaries. This is protected
  * with CONFIG_SAFE_BITSTREAM_READER at the global level, and
  * then below that with UNCHECKED_BITSTREAM_READER at the per-
  * decoder level. This means that decoders that check internally
  * can "#define UNCHECKED_BITSTREAM_READER 1" to disable
  * overread checks.
  * Boundary checking causes a minor performance penalty so for
  * applications that won't want/need this, it can be disabled
  * globally using "#define CONFIG_SAFE_BITSTREAM_READER 0".
  */
 #ifndef UNCHECKED_BITSTREAM_READER
 #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
 #endif

 typedef struct GetBitContext {
     const uint8_t *buffer, *buffer_end;
     int index;
     int size_in_bits;
     int size_in_bits_plus8;
 } GetBitContext;

 #define VLC_TYPE int16_t

 typedef struct VLC {
     int bits;
     VLC_TYPE (*table)[2]; ///< code, bits
     int table_size, table_allocated;
 } VLC;

 typedef struct RL_VLC_ELEM {
     int16_t level;
     int8_t len;
     uint8_t run;
 } RL_VLC_ELEM;

 /* Bitstream reader API docs:
  * name
  *   arbitrary name which is used as prefix for the internal variables
  *
  * gb
  *   getbitcontext
  *
  * OPEN_READER(name, gb)
  *   load gb into local variables
  *
  * CLOSE_READER(name, gb)
  *   store local vars in gb
  *
  * UPDATE_CACHE(name, gb)
  *   Refill the internal cache from the bitstream.
  *   After this call at least MIN_CACHE_BITS will be available.
  *
  * GET_CACHE(name, gb)
  *   Will output the contents of the internal cache,
  *   next bit is MSB of 32 or 64 bit (FIXME 64bit).
  *
  * SHOW_UBITS(name, gb, num)
  *   Will return the next num bits.
  *
  * SHOW_SBITS(name, gb, num)
  *   Will return the next num bits and do sign extension.
  *
  * SKIP_BITS(name, gb, num)
  *   Will skip over the next num bits.
  *   Note, this is equivalent to SKIP_CACHE; SKIP_COUNTER.
  *
  * SKIP_CACHE(name, gb, num)
  *   Will remove the next num bits from the cache (note SKIP_COUNTER
  *   MUST be called before UPDATE_CACHE / CLOSE_READER).
  *
  * SKIP_COUNTER(name, gb, num)
  *   Will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS).
  *
  * LAST_SKIP_BITS(name, gb, num)
  *   Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER.
  *
  * BITS_LEFT(name, gb)
  *   Return the number of bits left
  *
  * For examples see get_bits, show_bits, skip_bits, get_vlc.
  */

 #ifdef LONG_BITSTREAM_READER
 #   define MIN_CACHE_BITS 32
 #else
 #   define MIN_CACHE_BITS 25
 #endif

 #define OPEN_READER_NOSIZE(name, gb)            \
     unsigned int name ## _index = (gb)->index;  \
     unsigned int av_unused name ## _cache

 #if UNCHECKED_BITSTREAM_READER
 #define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb)

 #define BITS_AVAILABLE(name, gb) 1
 #else
 #define OPEN_READER(name, gb)                   \
     OPEN_READER_NOSIZE(name, gb);               \
     unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8

 #define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8
 #endif

 #define CLOSE_READER(name, gb) (gb)->index = name ## _index

 # ifdef LONG_BITSTREAM_READER

 # define UPDATE_CACHE_LE(name, gb) name ## _cache = \
       AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)

 # define UPDATE_CACHE_BE(name, gb) name ## _cache = \
       AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7))

 #else

 # define UPDATE_CACHE_LE(name, gb) name ## _cache = \
       AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)

 # define UPDATE_CACHE_BE(name, gb) name ## _cache = \
       AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7)

 #endif


 #ifdef BITSTREAM_READER_LE

 # define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb)

 # define SKIP_CACHE(name, gb, num) name ## _cache >>= (num)

 #else

 # define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb)

 # define SKIP_CACHE(name, gb, num) name ## _cache <<= (num)

 #endif

 #if UNCHECKED_BITSTREAM_READER
 #   define SKIP_COUNTER(name, gb, num) name ## _index += (num)
 #else
 #   define SKIP_COUNTER(name, gb, num) \
     name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num))
 #endif

 #define BITS_LEFT(name, gb) ((int)((gb)->size_in_bits - name ## _index))

 #define SKIP_BITS(name, gb, num)                \
     do {                                        \
         SKIP_CACHE(name, gb, num);              \
         SKIP_COUNTER(name, gb, num);            \
     } while (0)

 #define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)

 #define SHOW_UBITS_LE(name, gb, num) zero_extend(name ## _cache, num)
 #define SHOW_SBITS_LE(name, gb, num) sign_extend(name ## _cache, num)

 #define SHOW_UBITS_BE(name, gb, num) NEG_USR32(name ## _cache, num)
 #define SHOW_SBITS_BE(name, gb, num) NEG_SSR32(name ## _cache, num)

 #ifdef BITSTREAM_READER_LE
 #   define SHOW_UBITS(name, gb, num) SHOW_UBITS_LE(name, gb, num)
 #   define SHOW_SBITS(name, gb, num) SHOW_SBITS_LE(name, gb, num)
 #else
 #   define SHOW_UBITS(name, gb, num) SHOW_UBITS_BE(name, gb, num)
 #   define SHOW_SBITS(name, gb, num) SHOW_SBITS_BE(name, gb, num)
 #endif

 #define GET_CACHE(name, gb) ((uint32_t) name ## _cache)

 static inline int get_bits_count(const GetBitContext *s)
 {
     return s->index;
 }

 static inline void skip_bits_long(GetBitContext *s, int n)
 {
 #if UNCHECKED_BITSTREAM_READER
     s->index += n;
 #else
     s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index);
 #endif
 }

 /**
  * read mpeg1 dc style vlc (sign bit + mantissa with no MSB).
  * if MSB not set it is negative
  * @param n length in bits
  */
 static inline int get_xbits(GetBitContext *s, int n)
 {
     register int sign;
     register int32_t cache;
     OPEN_READER(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE(re, s);
     cache = GET_CACHE(re, s);
     sign  = ~cache >> 31;
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
     return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
 }

 static inline int get_sbits(GetBitContext *s, int n)
 {
     register int tmp;
     OPEN_READER(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE(re, s);
     tmp = SHOW_SBITS(re, s, n);
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
     return tmp;
 }

 /**
  * Read 1-25 bits.
  */
 static inline unsigned int get_bits(GetBitContext *s, int n)
 {
     register int tmp;
     OPEN_READER(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE(re, s);
     tmp = SHOW_UBITS(re, s, n);
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
     return tmp;
 }

 /**
  * Read 0-25 bits.
  */
 static av_always_inline int get_bitsz(GetBitContext *s, int n)
 {
     return n ? get_bits(s, n) : 0;
 }

 static inline unsigned int get_bits_le(GetBitContext *s, int n)
 {
     register int tmp;
     OPEN_READER(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE_LE(re, s);
     tmp = SHOW_UBITS_LE(re, s, n);
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
     return tmp;
 }

 /**
  * Show 1-25 bits.
  */
 static inline unsigned int show_bits(GetBitContext *s, int n)
 {
     register int tmp;
     OPEN_READER_NOSIZE(re, s);
     av_assert2(n>0 && n<=25);
     UPDATE_CACHE(re, s);
     tmp = SHOW_UBITS(re, s, n);
     return tmp;
 }

 static inline void skip_bits(GetBitContext *s, int n)
 {
     OPEN_READER(re, s);
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
 }

 static inline unsigned int get_bits1(GetBitContext *s)
 {
     unsigned int index = s->index;
     uint8_t result     = s->buffer[index >> 3];
 #ifdef BITSTREAM_READER_LE
     result >>= index & 7;
     result  &= 1;
 #else
     result <<= index & 7;
     result >>= 8 - 1;
 #endif
 #if !UNCHECKED_BITSTREAM_READER
     if (s->index < s->size_in_bits_plus8)
 #endif
         index++;
     s->index = index;

     return result;
 }

 static inline unsigned int show_bits1(GetBitContext *s)
 {
     return show_bits(s, 1);
 }

 static inline void skip_bits1(GetBitContext *s)
 {
     skip_bits(s, 1);
 }

 /**
  * Read 0-32 bits.
  */
 static inline unsigned int get_bits_long(GetBitContext *s, int n)
 {
     if (!n) {
         return 0;
     } else if (n <= MIN_CACHE_BITS) {
         return get_bits(s, n);
     } else {
 #ifdef BITSTREAM_READER_LE
         unsigned ret = get_bits(s, 16);
         return ret | (get_bits(s, n - 16) << 16);
 #else
         unsigned ret = get_bits(s, 16) << (n - 16);
         return ret | get_bits(s, n - 16);
 #endif
     }
 }

 /**
  * Read 0-64 bits.
  */
 static inline uint64_t get_bits64(GetBitContext *s, int n)
 {
     if (n <= 32) {
         return get_bits_long(s, n);
     } else {
 #ifdef BITSTREAM_READER_LE
         uint64_t ret = get_bits_long(s, 32);
         return ret | (uint64_t) get_bits_long(s, n - 32) << 32;
 #else
         uint64_t ret = (uint64_t) get_bits_long(s, n - 32) << 32;
         return ret | get_bits_long(s, 32);
 #endif
     }
 }

 /**
  * Read 0-32 bits as a signed integer.
  */
 static inline int get_sbits_long(GetBitContext *s, int n)
 {
     return sign_extend(get_bits_long(s, n), n);
 }

 /**
  * Show 0-32 bits.
  */
 static inline unsigned int show_bits_long(GetBitContext *s, int n)
 {
     if (n <= MIN_CACHE_BITS) {
         return show_bits(s, n);
     } else {
         GetBitContext gb = *s;
         return get_bits_long(&gb, n);
     }
 }

 static inline int check_marker(GetBitContext *s, const char *msg)
 {
     int bit = get_bits1(s);
     if (!bit)
         av_log(NULL, AV_LOG_INFO, "Marker bit missing at %d of %d %s\n", get_bits_count(s) - 1, s->size_in_bits, msg);

     return bit;
 }

 /**
  * Initialize GetBitContext.
  * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
  *        larger than the actual read bits because some optimized bitstream
  *        readers read 32 or 64 bit at once and could read over the end
  * @param bit_size the size of the buffer in bits
  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
  */
 static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
                                 int bit_size)
 {
     int buffer_size;
     int ret = 0;

     if (bit_size >= INT_MAX - 7 || bit_size < 0 || !buffer) {
         bit_size    = 0;
         buffer      = NULL;
         ret         = AVERROR_INVALIDDATA;
     }

     buffer_size = (bit_size + 7) >> 3;

     s->buffer             = buffer;
     s->size_in_bits       = bit_size;
     s->size_in_bits_plus8 = bit_size + 8;
     s->buffer_end         = buffer + buffer_size;
     s->index              = 0;

     return ret;
 }

 /**
  * Initialize GetBitContext.
  * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
  *        larger than the actual read bits because some optimized bitstream
  *        readers read 32 or 64 bit at once and could read over the end
  * @param byte_size the size of the buffer in bytes
  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
  */
 static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer,
                                  int byte_size)
 {
     if (byte_size > INT_MAX / 8 || byte_size < 0)
         byte_size = -1;
     return init_get_bits(s, buffer, byte_size * 8);
 }

 static inline const uint8_t *align_get_bits(GetBitContext *s)
 {
     int n = -get_bits_count(s) & 7;
     if (n)
         skip_bits(s, n);
     return s->buffer + (s->index >> 3);
 }

 #define init_vlc(vlc, nb_bits, nb_codes,                \
                  bits, bits_wrap, bits_size,            \
                  codes, codes_wrap, codes_size,         \
                  flags)                                 \
     ff_init_vlc_sparse(vlc, nb_bits, nb_codes,          \
                        bits, bits_wrap, bits_size,      \
                        codes, codes_wrap, codes_size,   \
                        NULL, 0, 0, flags)

 int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
                        const void *bits, int bits_wrap, int bits_size,
                        const void *codes, int codes_wrap, int codes_size,
                        const void *symbols, int symbols_wrap, int symbols_size,
                        int flags);
 void ff_free_vlc(VLC *vlc);

 #define INIT_VLC_LE             2
 #define INIT_VLC_USE_NEW_STATIC 4

 #define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size)       \
     do {                                                                   \
         static VLC_TYPE table[static_size][2];                             \
         (vlc)->table           = table;                                    \
         (vlc)->table_allocated = static_size;                              \
         init_vlc(vlc, bits, a, b, c, d, e, f, g, INIT_VLC_USE_NEW_STATIC); \
     } while (0)

 /**
  * If the vlc code is invalid and max_depth=1, then no bits will be removed.
  * If the vlc code is invalid and max_depth>1, then the number of bits removed
  * is undefined.
  */
 #define GET_VLC(code, name, gb, table, bits, max_depth)         \
     do {                                                        \
         int n, nb_bits;                                         \
         unsigned int index;                                     \
                                                                 \
         index = SHOW_UBITS(name, gb, bits);                     \
         code  = table[index][0];                                \
         n     = table[index][1];                                \
                                                                 \
         if (max_depth > 1 && n < 0) {                           \
             LAST_SKIP_BITS(name, gb, bits);                     \
             UPDATE_CACHE(name, gb);                             \
                                                                 \
             nb_bits = -n;                                       \
                                                                 \
             index = SHOW_UBITS(name, gb, nb_bits) + code;       \
             code  = table[index][0];                            \
             n     = table[index][1];                            \
             if (max_depth > 2 && n < 0) {                       \
                 LAST_SKIP_BITS(name, gb, nb_bits);              \
                 UPDATE_CACHE(name, gb);                         \
                                                                 \
                 nb_bits = -n;                                   \
                                                                 \
                 index = SHOW_UBITS(name, gb, nb_bits) + code;   \
                 code  = table[index][0];                        \
                 n     = table[index][1];                        \
             }                                                   \
         }                                                       \
         SKIP_BITS(name, gb, n);                                 \
     } while (0)

 #define GET_RL_VLC_INTERNAL(level, run, name, gb, table, bits,  \
                    max_depth, need_update)                      \
     do {                                                        \
         int n, nb_bits;                                         \
         unsigned int index;                                     \
                                                                 \
         index = SHOW_UBITS(name, gb, bits);                     \
         level = table[index].level;                             \
         n     = table[index].len;                               \
                                                                 \
         if (max_depth > 1 && n < 0) {                           \
             SKIP_BITS(name, gb, bits);                          \
             if (need_update) {                                  \
                 UPDATE_CACHE(name, gb);                         \
             }                                                   \
                                                                 \
             nb_bits = -n;                                       \
                                                                 \
             index = SHOW_UBITS(name, gb, nb_bits) + level;      \
             level = table[index].level;                         \
             n     = table[index].len;                           \
             if (max_depth > 2 && n < 0) {                       \
                 LAST_SKIP_BITS(name, gb, nb_bits);              \
                 if (need_update) {                              \
                     UPDATE_CACHE(name, gb);                     \
                 }                                               \
                 nb_bits = -n;                                   \
                                                                 \
                 index = SHOW_UBITS(name, gb, nb_bits) + level;  \
                 level = table[index].level;                     \
                 n     = table[index].len;                       \
             }                                                   \
         }                                                       \
         run = table[index].run;                                 \
         SKIP_BITS(name, gb, n);                                 \
     } while (0)

 /**
  * Parse a vlc code.
  * @param bits is the number of bits which will be read at once, must be
  *             identical to nb_bits in init_vlc()
  * @param max_depth is the number of times bits bits must be read to completely
  *                  read the longest vlc code
  *                  = (max_vlc_length + bits - 1) / bits
  */
 static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
                                      int bits, int max_depth)
 {
     int code;

     OPEN_READER(re, s);
     UPDATE_CACHE(re, s);

     GET_VLC(code, re, s, table, bits, max_depth);

     CLOSE_READER(re, s);

     return code;
 }

 static inline int decode012(GetBitContext *gb)
 {
     int n;
     n = get_bits1(gb);
     if (n == 0)
         return 0;
     else
         return get_bits1(gb) + 1;
 }

 static inline int decode210(GetBitContext *gb)
 {
     if (get_bits1(gb))
         return 0;
     else
         return 2 - get_bits1(gb);
 }

 static inline int get_bits_left(GetBitContext *gb)
 {
     return gb->size_in_bits - get_bits_count(gb);
 }

 static inline int skip_1stop_8data_bits(GetBitContext *gb)
 {
     if (get_bits_left(gb) <= 0)
         return AVERROR_INVALIDDATA;

     while (get_bits1(gb)) {
         skip_bits(gb, 8);
         if (get_bits_left(gb) <= 0)
             return AVERROR_INVALIDDATA;
     }

     return 0;
 }

 //#define TRACE

 #ifdef TRACE
 static inline void print_bin(int bits, int n)
 {
     int i;

     for (i = n - 1; i >= 0; i--)
         av_log(NULL, AV_LOG_DEBUG, "%d", (bits >> i) & 1);
     for (i = n; i < 24; i++)
         av_log(NULL, AV_LOG_DEBUG, " ");
 }

 static inline int get_bits_trace(GetBitContext *s, int n, const char *file,
                                  const char *func, int line)
 {
     int r = get_bits(s, n);

     print_bin(r, n);
     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);

     return r;
 }

 static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2],
                                 int bits, int max_depth, const char *file,
                                 const char *func, int line)
 {
     int show  = show_bits(s, 24);
     int pos   = get_bits_count(s);
     int r     = get_vlc2(s, table, bits, max_depth);
     int len   = get_bits_count(s) - pos;
     int bits2 = show >> (24 - len);

     print_bin(bits2, len);

     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n",
            bits2, len, r, pos, file, func, line);

     return r;
 }

 #define GET_RL_VLC(level, run, name, gb, table, bits,           \
                    max_depth, need_update)                      \
     do {                                                        \
         int show  = SHOW_UBITS(name, gb, 24);                   \
         int len;                                                \
         int pos = name ## _index;                               \
                                                                 \
         GET_RL_VLC_INTERNAL(level, run, name, gb, table, bits,max_depth, need_update); \
                                                                 \
         len = name ## _index - pos + 1;                         \
         show = show >> (24 - len);                              \
                                                                 \
         print_bin(show, len);                                   \
                                                                 \
         av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d/%-3d rlv @%5d in %s %s:%d\n",\
                show, len, run-1, level, pos, __FILE__, __PRETTY_FUNCTION__, __LINE__);\
     } while (0)                                                 \


 static inline int get_xbits_trace(GetBitContext *s, int n, const char *file,
                                   const char *func, int line)
 {
     int show = show_bits(s, n);
     int r    = get_xbits(s, n);

     print_bin(show, n);
     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);

     return r;
 }

 #define get_bits(s, n)  get_bits_trace(s , n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 #define get_bits1(s)    get_bits_trace(s,  1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 #define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)

 #define get_vlc(s, vlc)             get_vlc_trace(s, (vlc)->table, (vlc)->bits,   3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 #define get_vlc2(s, tab, bits, max) get_vlc_trace(s,          tab,        bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 #else //TRACE
 #define GET_RL_VLC GET_RL_VLC_INTERNAL
 #endif

 #endif /* AVCODEC_GET_BITS_H */
	/*
	* copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
	*
	* This file is part of FFmpeg.
	*
	* FFmpeg is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* FFmpeg is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with FFmpeg; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	/**
	* @file
	* bitstream reader API header.
	*/

	#ifndef AVCODEC_GET_BITS_H
	#define AVCODEC_GET_BITS_H

	#include <stdint.h>

	#include "libavutil/common.h"
	#include "libavutil/intreadwrite.h"
	#include "libavutil/log.h"
	#include "libavutil/avassert.h"
	#include "mathops.h"

	/*
	* Safe bitstream reading:
	* optionally, the get_bits API can check to ensure that we
	* don't read past input buffer boundaries. This is protected
	* with CONFIG_SAFE_BITSTREAM_READER at the global level, and
	* then below that with UNCHECKED_BITSTREAM_READER at the per-
	* decoder level. This means that decoders that check internally
	* can "#define UNCHECKED_BITSTREAM_READER 1" to disable
	* overread checks.
	* Boundary checking causes a minor performance penalty so for
	* applications that won't want/need this, it can be disabled
	* globally using "#define CONFIG_SAFE_BITSTREAM_READER 0".
	*/
	#ifndef UNCHECKED_BITSTREAM_READER
	#define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
	#endif

	typedef struct GetBitContext {
	const uint8_t buffer, buffer_end;
	int index;
	int size_in_bits;
	int size_in_bits_plus8;
	} GetBitContext;

	#define VLC_TYPE int16_t

	typedef struct VLC {
	int bits;
	VLC_TYPE (*table)[2]; ///< code, bits
	int table_size, table_allocated;
	} VLC;

	typedef struct RL_VLC_ELEM {
	int16_t level;
	int8_t len;
	uint8_t run;
	} RL_VLC_ELEM;

	/* Bitstream reader API docs:
	* name
	* arbitrary name which is used as prefix for the internal variables
	*
	* gb
	* getbitcontext
	*
	* OPEN_READER(name, gb)
	* load gb into local variables
	*
	* CLOSE_READER(name, gb)
	* store local vars in gb
	*
	* UPDATE_CACHE(name, gb)
	* Refill the internal cache from the bitstream.
	* After this call at least MIN_CACHE_BITS will be available.
	*
	* GET_CACHE(name, gb)
	* Will output the contents of the internal cache,
	* next bit is MSB of 32 or 64 bit (FIXME 64bit).
	*
	* SHOW_UBITS(name, gb, num)
	* Will return the next num bits.
	*
	* SHOW_SBITS(name, gb, num)
	* Will return the next num bits and do sign extension.
	*
	* SKIP_BITS(name, gb, num)
	* Will skip over the next num bits.
	* Note, this is equivalent to SKIP_CACHE; SKIP_COUNTER.
	*
	* SKIP_CACHE(name, gb, num)
	* Will remove the next num bits from the cache (note SKIP_COUNTER
	* MUST be called before UPDATE_CACHE / CLOSE_READER).
	*
	* SKIP_COUNTER(name, gb, num)
	* Will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS).
	*
	* LAST_SKIP_BITS(name, gb, num)
	* Like SKIP_BITS, to be used if next call is UPDATE_CACHE or CLOSE_READER.
	*
	* BITS_LEFT(name, gb)
	* Return the number of bits left
	*
	* For examples see get_bits, show_bits, skip_bits, get_vlc.
	*/

	#ifdef LONG_BITSTREAM_READER
	# define MIN_CACHE_BITS 32
	#else
	# define MIN_CACHE_BITS 25
	#endif

	#define OPEN_READER_NOSIZE(name, gb) \
	unsigned int name ## _index = (gb)->index; \
	unsigned int av_unused name ## _cache

	#if UNCHECKED_BITSTREAM_READER
	#define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb)

	#define BITS_AVAILABLE(name, gb) 1
	#else
	#define OPEN_READER(name, gb) \
	OPEN_READER_NOSIZE(name, gb); \
	unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8

	#define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8
	#endif

	#define CLOSE_READER(name, gb) (gb)->index = name ## _index

	# ifdef LONG_BITSTREAM_READER

	# define UPDATE_CACHE_LE(name, gb) name ## _cache = \
	AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)

	# define UPDATE_CACHE_BE(name, gb) name ## _cache = \
	AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7))

	#else

	# define UPDATE_CACHE_LE(name, gb) name ## _cache = \
	AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)

	# define UPDATE_CACHE_BE(name, gb) name ## _cache = \
	AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7)

	#endif


	#ifdef BITSTREAM_READER_LE

	# define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb)

	# define SKIP_CACHE(name, gb, num) name ## _cache >>= (num)

	#else

	# define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb)

	# define SKIP_CACHE(name, gb, num) name ## _cache <<= (num)

	#endif

	#if UNCHECKED_BITSTREAM_READER
	# define SKIP_COUNTER(name, gb, num) name ## _index += (num)
	#else
	# define SKIP_COUNTER(name, gb, num) \
	name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num))
	#endif

	#define BITS_LEFT(name, gb) ((int)((gb)->size_in_bits - name ## _index))

	#define SKIP_BITS(name, gb, num) \
	do { \
	SKIP_CACHE(name, gb, num); \
	SKIP_COUNTER(name, gb, num); \
	} while (0)

	#define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)

	#define SHOW_UBITS_LE(name, gb, num) zero_extend(name ## _cache, num)
	#define SHOW_SBITS_LE(name, gb, num) sign_extend(name ## _cache, num)

	#define SHOW_UBITS_BE(name, gb, num) NEG_USR32(name ## _cache, num)
	#define SHOW_SBITS_BE(name, gb, num) NEG_SSR32(name ## _cache, num)

	#ifdef BITSTREAM_READER_LE
	# define SHOW_UBITS(name, gb, num) SHOW_UBITS_LE(name, gb, num)
	# define SHOW_SBITS(name, gb, num) SHOW_SBITS_LE(name, gb, num)
	#else
	# define SHOW_UBITS(name, gb, num) SHOW_UBITS_BE(name, gb, num)
	# define SHOW_SBITS(name, gb, num) SHOW_SBITS_BE(name, gb, num)
	#endif

	#define GET_CACHE(name, gb) ((uint32_t) name ## _cache)

	static inline int get_bits_count(const GetBitContext *s)
	{
	return s->index;
	}

	static inline void skip_bits_long(GetBitContext *s, int n)
	{
	#if UNCHECKED_BITSTREAM_READER
	s->index += n;
	#else
	s->index += av_clip(n, -s->index, s->size_in_bits_plus8 - s->index);
	#endif
	}

	/**
	* read mpeg1 dc style vlc (sign bit + mantissa with no MSB).
	* if MSB not set it is negative
	* @param n length in bits
	*/
	static inline int get_xbits(GetBitContext *s, int n)
	{
	register int sign;
	register int32_t cache;
	OPEN_READER(re, s);
	av_assert2(n>0 && n<=25);
	UPDATE_CACHE(re, s);
	cache = GET_CACHE(re, s);
	sign = ~cache >> 31;
	LAST_SKIP_BITS(re, s, n);
	CLOSE_READER(re, s);
	return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
	}

	static inline int get_sbits(GetBitContext *s, int n)
	{
	register int tmp;
	OPEN_READER(re, s);
	av_assert2(n>0 && n<=25);
	UPDATE_CACHE(re, s);
	tmp = SHOW_SBITS(re, s, n);
	LAST_SKIP_BITS(re, s, n);
	CLOSE_READER(re, s);
	return tmp;
	}

	/**
	* Read 1-25 bits.
	*/
	static inline unsigned int get_bits(GetBitContext *s, int n)
	{
	register int tmp;
	OPEN_READER(re, s);
	av_assert2(n>0 && n<=25);
	UPDATE_CACHE(re, s);
	tmp = SHOW_UBITS(re, s, n);
	LAST_SKIP_BITS(re, s, n);
	CLOSE_READER(re, s);
	return tmp;
	}

	/**
	* Read 0-25 bits.
	*/
	static av_always_inline int get_bitsz(GetBitContext *s, int n)
	{
	return n ? get_bits(s, n) : 0;
	}

	static inline unsigned int get_bits_le(GetBitContext *s, int n)
	{
	register int tmp;
	OPEN_READER(re, s);
	av_assert2(n>0 && n<=25);
	UPDATE_CACHE_LE(re, s);
	tmp = SHOW_UBITS_LE(re, s, n);
	LAST_SKIP_BITS(re, s, n);
	CLOSE_READER(re, s);
	return tmp;
	}

	/**
	* Show 1-25 bits.
	*/
	static inline unsigned int show_bits(GetBitContext *s, int n)
	{
	register int tmp;
	OPEN_READER_NOSIZE(re, s);
	av_assert2(n>0 && n<=25);
	UPDATE_CACHE(re, s);
	tmp = SHOW_UBITS(re, s, n);
	return tmp;
	}

	static inline void skip_bits(GetBitContext *s, int n)
	{
	OPEN_READER(re, s);
	LAST_SKIP_BITS(re, s, n);
	CLOSE_READER(re, s);
	}

	static inline unsigned int get_bits1(GetBitContext *s)
	{
	unsigned int index = s->index;
	uint8_t result = s->buffer[index >> 3];
	#ifdef BITSTREAM_READER_LE
	result >>= index & 7;
	result &= 1;
	#else
	result <<= index & 7;
	result >>= 8 - 1;
	#endif
	#if !UNCHECKED_BITSTREAM_READER
	if (s->index < s->size_in_bits_plus8)
	#endif
	index++;
	s->index = index;

	return result;
	}

	static inline unsigned int show_bits1(GetBitContext *s)
	{
	return show_bits(s, 1);
	}

	static inline void skip_bits1(GetBitContext *s)
	{
	skip_bits(s, 1);
	}

	/**
	* Read 0-32 bits.
	*/
	static inline unsigned int get_bits_long(GetBitContext *s, int n)
	{
	if (!n) {
	return 0;
	} else if (n <= MIN_CACHE_BITS) {
	return get_bits(s, n);
	} else {
	#ifdef BITSTREAM_READER_LE
	unsigned ret = get_bits(s, 16);
	return ret \| (get_bits(s, n - 16) << 16);
	#else
	unsigned ret = get_bits(s, 16) << (n - 16);
	return ret \| get_bits(s, n - 16);
	#endif
	}
	}

	/**
	* Read 0-64 bits.
	*/
	static inline uint64_t get_bits64(GetBitContext *s, int n)
	{
	if (n <= 32) {
	return get_bits_long(s, n);
	} else {
	#ifdef BITSTREAM_READER_LE
	uint64_t ret = get_bits_long(s, 32);
	return ret \| (uint64_t) get_bits_long(s, n - 32) << 32;
	#else
	uint64_t ret = (uint64_t) get_bits_long(s, n - 32) << 32;
	return ret \| get_bits_long(s, 32);
	#endif
	}
	}

	/**
	* Read 0-32 bits as a signed integer.
	*/
	static inline int get_sbits_long(GetBitContext *s, int n)
	{
	return sign_extend(get_bits_long(s, n), n);
	}

	/**
	* Show 0-32 bits.
	*/
	static inline unsigned int show_bits_long(GetBitContext *s, int n)
	{
	if (n <= MIN_CACHE_BITS) {
	return show_bits(s, n);
	} else {
	GetBitContext gb = *s;
	return get_bits_long(&gb, n);
	}
	}

	static inline int check_marker(GetBitContext s, const char msg)
	{
	int bit = get_bits1(s);
	if (!bit)
	av_log(NULL, AV_LOG_INFO, "Marker bit missing at %d of %d %s\n", get_bits_count(s) - 1, s->size_in_bits, msg);

	return bit;
	}

	/**
	* Initialize GetBitContext.
	* @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
	* larger than the actual read bits because some optimized bitstream
	* readers read 32 or 64 bit at once and could read over the end
	* @param bit_size the size of the buffer in bits
	* @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
	*/
	static inline int init_get_bits(GetBitContext s, const uint8_t buffer,
	int bit_size)
	{
	int buffer_size;
	int ret = 0;

	if (bit_size >= INT_MAX - 7 \|\| bit_size < 0 \|\| !buffer) {
	bit_size = 0;
	buffer = NULL;
	ret = AVERROR_INVALIDDATA;
	}

	buffer_size = (bit_size + 7) >> 3;

	s->buffer = buffer;
	s->size_in_bits = bit_size;
	s->size_in_bits_plus8 = bit_size + 8;
	s->buffer_end = buffer + buffer_size;
	s->index = 0;

	return ret;
	}

	/**
	* Initialize GetBitContext.
	* @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
	* larger than the actual read bits because some optimized bitstream
	* readers read 32 or 64 bit at once and could read over the end
	* @param byte_size the size of the buffer in bytes
	* @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
	*/
	static inline int init_get_bits8(GetBitContext s, const uint8_t buffer,
	int byte_size)
	{
	if (byte_size > INT_MAX / 8 \|\| byte_size < 0)
	byte_size = -1;
	return init_get_bits(s, buffer, byte_size * 8);
	}

	static inline const uint8_t align_get_bits(GetBitContext s)
	{
	int n = -get_bits_count(s) & 7;
	if (n)
	skip_bits(s, n);
	return s->buffer + (s->index >> 3);
	}

	#define init_vlc(vlc, nb_bits, nb_codes, \
	bits, bits_wrap, bits_size, \
	codes, codes_wrap, codes_size, \
	flags) \
	ff_init_vlc_sparse(vlc, nb_bits, nb_codes, \
	bits, bits_wrap, bits_size, \
	codes, codes_wrap, codes_size, \
	NULL, 0, 0, flags)

	int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
	const void *bits, int bits_wrap, int bits_size,
	const void *codes, int codes_wrap, int codes_size,
	const void *symbols, int symbols_wrap, int symbols_size,
	int flags);
	void ff_free_vlc(VLC *vlc);

	#define INIT_VLC_LE 2
	#define INIT_VLC_USE_NEW_STATIC 4

	#define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size) \
	do { \
	static VLC_TYPE table[static_size][2]; \
	(vlc)->table = table; \
	(vlc)->table_allocated = static_size; \
	init_vlc(vlc, bits, a, b, c, d, e, f, g, INIT_VLC_USE_NEW_STATIC); \
	} while (0)

	/**
	* If the vlc code is invalid and max_depth=1, then no bits will be removed.
	* If the vlc code is invalid and max_depth>1, then the number of bits removed
	* is undefined.
	*/
	#define GET_VLC(code, name, gb, table, bits, max_depth) \
	do { \
	int n, nb_bits; \
	unsigned int index; \
	\
	index = SHOW_UBITS(name, gb, bits); \
	code = table[index][0]; \
	n = table[index][1]; \
	\
	if (max_depth > 1 && n < 0) { \
	LAST_SKIP_BITS(name, gb, bits); \
	UPDATE_CACHE(name, gb); \
	\
	nb_bits = -n; \
	\
	index = SHOW_UBITS(name, gb, nb_bits) + code; \
	code = table[index][0]; \
	n = table[index][1]; \
	if (max_depth > 2 && n < 0) { \
	LAST_SKIP_BITS(name, gb, nb_bits); \
	UPDATE_CACHE(name, gb); \
	\
	nb_bits = -n; \
	\
	index = SHOW_UBITS(name, gb, nb_bits) + code; \
	code = table[index][0]; \
	n = table[index][1]; \
	} \
	} \
	SKIP_BITS(name, gb, n); \
	} while (0)

	#define GET_RL_VLC_INTERNAL(level, run, name, gb, table, bits, \
	max_depth, need_update) \
	do { \
	int n, nb_bits; \
	unsigned int index; \
	\
	index = SHOW_UBITS(name, gb, bits); \
	level = table[index].level; \
	n = table[index].len; \
	\
	if (max_depth > 1 && n < 0) { \
	SKIP_BITS(name, gb, bits); \
	if (need_update) { \
	UPDATE_CACHE(name, gb); \
	} \
	\
	nb_bits = -n; \
	\
	index = SHOW_UBITS(name, gb, nb_bits) + level; \
	level = table[index].level; \
	n = table[index].len; \
	if (max_depth > 2 && n < 0) { \
	LAST_SKIP_BITS(name, gb, nb_bits); \
	if (need_update) { \
	UPDATE_CACHE(name, gb); \
	} \
	nb_bits = -n; \
	\
	index = SHOW_UBITS(name, gb, nb_bits) + level; \
	level = table[index].level; \
	n = table[index].len; \
	} \
	} \
	run = table[index].run; \
	SKIP_BITS(name, gb, n); \
	} while (0)

	/**
	* Parse a vlc code.
	* @param bits is the number of bits which will be read at once, must be
	* identical to nb_bits in init_vlc()
	* @param max_depth is the number of times bits bits must be read to completely
	* read the longest vlc code
	* = (max_vlc_length + bits - 1) / bits
	*/
	static av_always_inline int get_vlc2(GetBitContext s, VLC_TYPE (table)[2],
	int bits, int max_depth)
	{
	int code;

	OPEN_READER(re, s);
	UPDATE_CACHE(re, s);

	GET_VLC(code, re, s, table, bits, max_depth);

	CLOSE_READER(re, s);

	return code;
	}

	static inline int decode012(GetBitContext *gb)
	{
	int n;
	n = get_bits1(gb);
	if (n == 0)
	return 0;
	else
	return get_bits1(gb) + 1;
	}

	static inline int decode210(GetBitContext *gb)
	{
	if (get_bits1(gb))
	return 0;
	else
	return 2 - get_bits1(gb);
	}

	static inline int get_bits_left(GetBitContext *gb)
	{
	return gb->size_in_bits - get_bits_count(gb);
	}

	static inline int skip_1stop_8data_bits(GetBitContext *gb)
	{
	if (get_bits_left(gb) <= 0)
	return AVERROR_INVALIDDATA;

	while (get_bits1(gb)) {
	skip_bits(gb, 8);
	if (get_bits_left(gb) <= 0)
	return AVERROR_INVALIDDATA;
	}

	return 0;
	}

	//#define TRACE

	#ifdef TRACE
	static inline void print_bin(int bits, int n)
	{
	int i;

	for (i = n - 1; i >= 0; i--)
	av_log(NULL, AV_LOG_DEBUG, "%d", (bits >> i) & 1);
	for (i = n; i < 24; i++)
	av_log(NULL, AV_LOG_DEBUG, " ");
	}

	static inline int get_bits_trace(GetBitContext s, int n, const char file,
	const char *func, int line)
	{
	int r = get_bits(s, n);

	print_bin(r, n);
	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);

	return r;
	}

	static inline int get_vlc_trace(GetBitContext s, VLC_TYPE (table)[2],
	int bits, int max_depth, const char *file,
	const char *func, int line)
	{
	int show = show_bits(s, 24);
	int pos = get_bits_count(s);
	int r = get_vlc2(s, table, bits, max_depth);
	int len = get_bits_count(s) - pos;
	int bits2 = show >> (24 - len);

	print_bin(bits2, len);

	av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n",
	bits2, len, r, pos, file, func, line);

	return r;
	}

	#define GET_RL_VLC(level, run, name, gb, table, bits, \
	max_depth, need_update) \
	do { \
	int show = SHOW_UBITS(name, gb, 24); \
	int len; \
	int pos = name ## _index; \
	\
	GET_RL_VLC_INTERNAL(level, run, name, gb, table, bits,max_depth, need_update); \
	\
	len = name ## _index - pos + 1; \
	show = show >> (24 - len); \
	\
	print_bin(show, len); \
	\
	av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d/%-3d rlv @%5d in %s %s:%d\n",\
	show, len, run-1, level, pos, __FILE__, __PRETTY_FUNCTION__, __LINE__);\
	} while (0) \


	static inline int get_xbits_trace(GetBitContext s, int n, const char file,
	const char *func, int line)
	{
	int show = show_bits(s, n);
	int r = get_xbits(s, n);

	print_bin(show, n);
	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);

	return r;
	}

	#define get_bits(s, n) get_bits_trace(s , n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
	#define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
	#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)

	#define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
	#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
	#else //TRACE
	#define GET_RL_VLC GET_RL_VLC_INTERNAL
	#endif

	#endif /* AVCODEC_GET_BITS_H */