1/* 2 * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21#ifndef AVUTIL_MATHEMATICS_H 22#define AVUTIL_MATHEMATICS_H 23 24#include <stdint.h> 25#include <math.h> 26#include "common.h" 27#include "rational.h" 28 29#ifndef M_E 30#define M_E 2.7182818284590452354 /* e */ 31#endif 32#ifndef M_LN2 33#define M_LN2 0.69314718055994530942 /* log_e 2 */ 34#endif 35#ifndef M_LN10 36#define M_LN10 2.30258509299404568402 /* log_e 10 */ 37#endif 38#ifndef M_PI 39#define M_PI 3.14159265358979323846 /* pi */ 40#endif 41#ifndef M_SQRT1_2 42#define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */ 43#endif 44 45enum AVRounding { 46 AV_ROUND_ZERO = 0, ///< Round toward zero. 47 AV_ROUND_INF = 1, ///< Round away from zero. 48 AV_ROUND_DOWN = 2, ///< Round toward -infinity. 49 AV_ROUND_UP = 3, ///< Round toward +infinity. 50 AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero. 51}; 52 53int64_t av_const av_gcd(int64_t a, int64_t b); 54 55/** 56 * Rescales a 64-bit integer with rounding to nearest. 57 * A simple a*b/c isn't possible as it can overflow. 58 */ 59int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const; 60 61/** 62 * Rescales a 64-bit integer with specified rounding. 63 * A simple a*b/c isn't possible as it can overflow. 64 */ 65int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const; 66 67/** 68 * Rescales a 64-bit integer by 2 rational numbers. 69 */ 70int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const; 71 72#endif /* AVUTIL_MATHEMATICS_H */ 73