Mercurial > hg > forks > libbpg
diff libavutil/intmath.h @ 0:772086c29cc7
Initial import.
author | Matti Hamalainen <ccr@tnsp.org> |
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date | Wed, 16 Nov 2016 11:16:33 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libavutil/intmath.h Wed Nov 16 11:16:33 2016 +0200 @@ -0,0 +1,178 @@ +/* + * Copyright (c) 2010 Mans Rullgard <mans@mansr.com> + * + * 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 + */ + +#ifndef AVUTIL_INTMATH_H +#define AVUTIL_INTMATH_H + +#include <stdint.h> + +#include "config.h" +#include "attributes.h" + +#if ARCH_ARM +# include "arm/intmath.h" +#endif + +/** + * @addtogroup lavu_internal + * @{ + */ + +#if HAVE_FAST_CLZ +#if AV_GCC_VERSION_AT_LEAST(3,4) +#ifndef ff_log2 +# define ff_log2(x) (31 - __builtin_clz((x)|1)) +# ifndef ff_log2_16bit +# define ff_log2_16bit av_log2 +# endif +#endif /* ff_log2 */ +#elif defined( __INTEL_COMPILER ) +#ifndef ff_log2 +# define ff_log2(x) (_bit_scan_reverse(x|1)) +# ifndef ff_log2_16bit +# define ff_log2_16bit av_log2 +# endif +#endif /* ff_log2 */ +#endif +#endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ + +extern const uint8_t ff_log2_tab[256]; + +#ifndef ff_log2 +#define ff_log2 ff_log2_c +#if !defined( _MSC_VER ) +static av_always_inline av_const int ff_log2_c(unsigned int v) +{ + int n = 0; + if (v & 0xffff0000) { + v >>= 16; + n += 16; + } + if (v & 0xff00) { + v >>= 8; + n += 8; + } + n += ff_log2_tab[v]; + + return n; +} +#else +static av_always_inline av_const int ff_log2_c(unsigned int v) +{ + unsigned long n; + _BitScanReverse(&n, v|1); + return n; +} +#define ff_log2_16bit av_log2 +#endif +#endif + +#ifndef ff_log2_16bit +#define ff_log2_16bit ff_log2_16bit_c +static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) +{ + int n = 0; + if (v & 0xff00) { + v >>= 8; + n += 8; + } + n += ff_log2_tab[v]; + + return n; +} +#endif + +#define av_log2 ff_log2 +#define av_log2_16bit ff_log2_16bit + +/** + * @} + */ + +/** + * @addtogroup lavu_math + * @{ + */ + +#if HAVE_FAST_CLZ +#if AV_GCC_VERSION_AT_LEAST(3,4) +#ifndef ff_ctz +#define ff_ctz(v) __builtin_ctz(v) +#endif +#elif defined( __INTEL_COMPILER ) +#ifndef ff_ctz +#define ff_ctz(v) _bit_scan_forward(v) +#endif +#endif +#endif + +#ifndef ff_ctz +#define ff_ctz ff_ctz_c +#if !defined( _MSC_VER ) +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; +} +#else +static av_always_inline av_const int ff_ctz_c( int v ) +{ + unsigned long c; + _BitScanForward(&c, v); + return c; +} +#endif +#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 */