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Diffstat (limited to 'media/libav/libavutil/mathematics.h')
-rw-r--r-- | media/libav/libavutil/mathematics.h | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/media/libav/libavutil/mathematics.h b/media/libav/libavutil/mathematics.h new file mode 100644 index 000000000..043dd0faf --- /dev/null +++ b/media/libav/libavutil/mathematics.h @@ -0,0 +1,111 @@ +/* + * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> + * + * This file is part of Libav. + * + * Libav 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. + * + * Libav 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 Libav; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef AVUTIL_MATHEMATICS_H +#define AVUTIL_MATHEMATICS_H + +#include <stdint.h> +#include <math.h> +#include "attributes.h" +#include "rational.h" +#include "intfloat.h" + +#ifndef M_LOG2_10 +#define M_LOG2_10 3.32192809488736234787 /* log_2 10 */ +#endif +#ifndef M_PHI +#define M_PHI 1.61803398874989484820 /* phi / golden ratio */ +#endif +#ifndef NAN +#define NAN av_int2float(0x7fc00000) +#endif +#ifndef INFINITY +#define INFINITY av_int2float(0x7f800000) +#endif + +/** + * @addtogroup lavu_math + * @{ + */ + + +enum AVRounding { + AV_ROUND_ZERO = 0, ///< Round toward zero. + AV_ROUND_INF = 1, ///< Round away from zero. + AV_ROUND_DOWN = 2, ///< Round toward -infinity. + AV_ROUND_UP = 3, ///< Round toward +infinity. + AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero. +}; + +/** + * Return the greatest common divisor of a and b. + * If both a and b are 0 or either or both are <0 then behavior is + * undefined. + */ +int64_t av_const av_gcd(int64_t a, int64_t b); + +/** + * Rescale a 64-bit integer with rounding to nearest. + * A simple a*b/c isn't possible as it can overflow. + */ +int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const; + +/** + * Rescale a 64-bit integer with specified rounding. + * A simple a*b/c isn't possible as it can overflow. + */ +int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const; + +/** + * Rescale a 64-bit integer by 2 rational numbers. + */ +int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const; + +/** + * Rescale a 64-bit integer by 2 rational numbers with specified rounding. + */ +int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq, + enum AVRounding) av_const; + +/** + * Compare 2 timestamps each in its own timebases. + * The result of the function is undefined if one of the timestamps + * is outside the int64_t range when represented in the others timebase. + * @return -1 if ts_a is before ts_b, 1 if ts_a is after ts_b or 0 if they represent the same position + */ +int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b); + +/** + * Compare 2 integers modulo mod. + * That is we compare integers a and b for which only the least + * significant log2(mod) bits are known. + * + * @param mod must be a power of 2 + * @return a negative value if a is smaller than b + * a positive value if a is greater than b + * 0 if a equals b + */ +int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod); + +/** + * @} + */ + +#endif /* AVUTIL_MATHEMATICS_H */ |