code / widevine-mirrored-source / 66427ffa50c9a1038998509907e91d0be9ced12a / . / ffmpeg-0.5 / libavutil / rational.h

/* | |

* rational numbers | |

* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> | |

* | |

* 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 <michaelni@gmx.at> | |

*/ | |

#ifndef AVUTIL_RATIONAL_H | |

#define AVUTIL_RATIONAL_H | |

#include <stdint.h> | |

#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<b | |

*/ | |

static inline int av_cmp_q(AVRational a, AVRational b){ | |

const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den; | |

if(tmp) return (tmp>>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 */ |