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 /* * rational numbers * Copyright (c) 2003 Michael Niedermayer * * 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 */ /** * @file libavutil/rational.h * rational numbers * @author Michael Niedermayer */ #ifndef AVUTIL_RATIONAL_H #define AVUTIL_RATIONAL_H #include #include "common.h" /** * rational number numerator/denominator */ typedef struct AVRational{ int num; ///< numerator int den; ///< denominator } AVRational; /** * Compares two rationals. * @param a first rational * @param b second rational * @return 0 if a==b, 1 if a>b and -1 if a>63)|1; else return 0; } /** * Converts rational to double. * @param a rational to convert * @return (double) a */ static inline double av_q2d(AVRational a){ return a.num / (double) a.den; } /** * Reduces a fraction. * This is useful for framerate calculations. * @param dst_num destination numerator * @param dst_den destination denominator * @param num source numerator * @param den source denominator * @param max the maximum allowed for dst_num & dst_den * @return 1 if exact, 0 otherwise */ int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max); /** * Multiplies two rationals. * @param b first rational * @param c second rational * @return b*c */ AVRational av_mul_q(AVRational b, AVRational c) av_const; /** * Divides one rational by another. * @param b first rational * @param c second rational * @return b/c */ AVRational av_div_q(AVRational b, AVRational c) av_const; /** * Adds two rationals. * @param b first rational * @param c second rational * @return b+c */ AVRational av_add_q(AVRational b, AVRational c) av_const; /** * Subtracts one rational from another. * @param b first rational * @param c second rational * @return b-c */ AVRational av_sub_q(AVRational b, AVRational c) av_const; /** * Converts a double precision floating point number to a rational. * @param d double to convert * @param max the maximum allowed numerator and denominator * @return (AVRational) d */ AVRational av_d2q(double d, int max) av_const; /** * @return 1 if \q1 is nearer to \p q than \p q2, -1 if \p q2 is nearer * than \p q1, 0 if they have the same distance. */ int av_nearer_q(AVRational q, AVRational q1, AVRational q2); /** * Finds the nearest value in \p q_list to \p q. * @param q_list an array of rationals terminated by {0, 0} * @return the index of the nearest value found in the array */ int av_find_nearest_q_idx(AVRational q, const AVRational* q_list); #endif /* AVUTIL_RATIONAL_H */