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| author | Justin Ruggles <justin.ruggles@gmail.com> | 2012-10-26 14:48:40 -0400 |
|---|---|---|
| committer | Justin Ruggles <justin.ruggles@gmail.com> | 2012-11-05 15:32:29 -0500 |
| commit | dfde8a34e5419ac99265e3ecc2e82f378674128a (patch) | |
| tree | 2eeec23b9d802e26b2483815c18475c7ff2075b3 /libavutil | |
| parent | 6a744d261930f8101132bc6d207b6eac41d9cf18 (diff) | |
| download | ffmpeg-dfde8a34e5419ac99265e3ecc2e82f378674128a.tar.gz | |
lavu: add av_ctz() for trailing zero bit count
Diffstat (limited to 'libavutil')
| -rw-r--r-- | libavutil/Makefile | 2 | ||||
| -rw-r--r-- | libavutil/intmath.c (renamed from libavutil/log2.c) | 5 | ||||
| -rw-r--r-- | libavutil/intmath.h | 55 | ||||
| -rw-r--r-- | libavutil/version.h | 2 |
4 files changed, 62 insertions, 2 deletions
diff --git a/libavutil/Makefile b/libavutil/Makefile index 45f8e9076c..d4ffd5e7d6 100644 --- a/libavutil/Makefile +++ b/libavutil/Makefile @@ -67,10 +67,10 @@ OBJS = adler32.o \ float_dsp.o \ imgutils.o \ intfloat_readwrite.o \ + intmath.o \ lfg.o \ lls.o \ log.o \ - log2.o \ log2_tab.o \ mathematics.o \ md5.o \ diff --git a/libavutil/log2.c b/libavutil/intmath.c index 18c1b40aaa..8db425c6e9 100644 --- a/libavutil/log2.c +++ b/libavutil/intmath.c @@ -32,3 +32,8 @@ int av_log2_16bit(unsigned v) { return ff_log2_16bit(v); } + +int av_ctz(int v) +{ + return ff_ctz(v); +} diff --git a/libavutil/intmath.h b/libavutil/intmath.h index 2cb313240b..a5ee6525ee 100644 --- a/libavutil/intmath.h +++ b/libavutil/intmath.h @@ -88,4 +88,59 @@ static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) /** * @} */ + +/** + * @addtogroup lavu_math + * @{ + */ + +#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4) +#ifndef ff_ctz +#define ff_ctz(v) __builtin_ctz(v) +#endif +#endif + +#ifndef ff_ctz +#define ff_ctz ff_ctz_c +static av_always_inline av_const int ff_ctz_c(int v) +{ + int c; + + if (v & 0x1) + return 0; + + c = 1; + if (!(v & 0xffff)) { + v >>= 16; + c += 16; + } + if (!(v & 0xff)) { + v >>= 8; + c += 8; + } + if (!(v & 0xf)) { + v >>= 4; + c += 4; + } + if (!(v & 0x3)) { + v >>= 2; + c += 2; + } + c -= v & 0x1; + + return c; +} +#endif + +/** + * Trailing zero bit count. + * + * @param v input value. If v is 0, the result is undefined. + * @return the number of trailing 0-bits + */ +int av_ctz(int v); + +/** + * @} + */ #endif /* AVUTIL_INTMATH_H */ diff --git a/libavutil/version.h b/libavutil/version.h index ae7fa7abeb..1659dbd537 100644 --- a/libavutil/version.h +++ b/libavutil/version.h @@ -37,7 +37,7 @@ */ #define LIBAVUTIL_VERSION_MAJOR 52 -#define LIBAVUTIL_VERSION_MINOR 0 +#define LIBAVUTIL_VERSION_MINOR 1 #define LIBAVUTIL_VERSION_MICRO 0 #define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \ |