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get_bits: add get_bits_le() 

Signed-off-by: Paul B Mahol <onemda@gmail.com>
This commit is contained in:
Paul B Mahol 2013-07-04 19:54:43 +00:00
parent 4e10d87f38
commit 48f2750de8
1 changed files with 43 additions and 18 deletions
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61
libavcodec/get_bits.h
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@ -139,27 +139,34 @@ typedef struct RL_VLC_ELEM {
#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
# ifdef LONG_BITSTREAM_READER
# define UPDATE_CACHE(name, gb) name ## _cache = \
AV_RL64((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)
# else
# define UPDATE_CACHE(name, gb) name ## _cache = \
AV_RL32((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7)
# endif
# define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb)
# define SKIP_CACHE(name, gb, num) name ## _cache >>= (num)
#else
# ifdef LONG_BITSTREAM_READER
# define UPDATE_CACHE(name, gb) name ## _cache = \
AV_RB64((gb)->buffer + (name ## _index >> 3)) >> (32 - (name ## _index & 7))
# else
# define UPDATE_CACHE(name, gb) name ## _cache = \
AV_RB32((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7)
# endif
# define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb)
# define SKIP_CACHE(name, gb, num) name ## _cache <<= (num)
@ -180,12 +187,18 @@ typedef struct RL_VLC_ELEM {
#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) zero_extend(name ## _cache, num)
# define SHOW_SBITS(name, gb, num) sign_extend(name ## _cache, num)
# 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) NEG_USR32(name ## _cache, num)
# define SHOW_SBITS(name, gb, num) NEG_SSR32(name ## _cache, num)
# 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)
@ -250,6 +263,18 @@ static inline unsigned int get_bits(GetBitContext *s, int n)
return tmp;
}
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.
*/