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author | Michael Niedermayer <michaelni@gmx.at> | 2012-11-05 22:51:20 +0100 |
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committer | Michael Niedermayer <michaelni@gmx.at> | 2012-11-05 22:51:20 +0100 |
commit | 7d26be63c25e715f008e8923654bdf318419dd39 (patch) | |
tree | c3d598d06854085a7e9f9474dee81e543f069cdb /libavutil/intmath.h | |
parent | e859339e7af52210c6fe84a8e6412f0c30d1c4da (diff) | |
parent | 5ff998a233d759d0de83ea6f95c383d03d25d88e (diff) | |
download | ffmpeg-7d26be63c25e715f008e8923654bdf318419dd39.tar.gz |
Merge commit '5ff998a233d759d0de83ea6f95c383d03d25d88e'
* commit '5ff998a233d759d0de83ea6f95c383d03d25d88e':
flacenc: use uint64_t for bit counts
flacenc: remove wasted trailing 0 bits
lavu: add av_ctz() for trailing zero bit count
flacenc: use a separate buffer for byte-swapping for MD5 checksum on big-endian
fate: aac: Place LATM tests and general AAC tests in different groups
build: The A64 muxer depends on rawenc.o for ff_raw_write_packet()
Conflicts:
doc/APIchanges
libavutil/version.h
tests/fate/aac.mak
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavutil/intmath.h')
-rw-r--r-- | libavutil/intmath.h | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/libavutil/intmath.h b/libavutil/intmath.h index 9002442bef..e140d822f3 100644 --- a/libavutil/intmath.h +++ b/libavutil/intmath.h @@ -92,4 +92,59 @@ 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 */ |