| /* |
| * 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 |
| * rational numbers |
| * @author Michael Niedermayer <michaelni@gmx.at> |
| */ |
| |
| #ifndef AVUTIL_RATIONAL_H |
| #define AVUTIL_RATIONAL_H |
| |
| #include <stdint.h> |
| #include <limits.h> |
| #include "attributes.h" |
| |
| /** |
| * @addtogroup lavu_math |
| * @{ |
| */ |
| |
| /** |
| * rational number numerator/denominator |
| */ |
| typedef struct AVRational{ |
| int num; ///< numerator |
| int den; ///< denominator |
| } AVRational; |
| |
| /** |
| * Create a rational. |
| * Useful for compilers that do not support compound literals. |
| * @note The return value is not reduced. |
| */ |
| static inline AVRational av_make_q(int num, int den) |
| { |
| AVRational r = { num, den }; |
| return r; |
| } |
| |
| /** |
| * Compare two rationals. |
| * @param a first rational |
| * @param b second rational |
| * @return 0 if a==b, 1 if a>b, -1 if a<b, and INT_MIN if one of the |
| * values is of the form 0/0 |
| */ |
| 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 (int)((tmp ^ a.den ^ b.den)>>63)|1; |
| else if(b.den && a.den) return 0; |
| else if(a.num && b.num) return (a.num>>31) - (b.num>>31); |
| else return INT_MIN; |
| } |
| |
| /** |
| * Convert rational to double. |
| * @param a rational to convert |
| * @return (double) a |
| */ |
| static inline double av_q2d(AVRational a){ |
| return a.num / (double) a.den; |
| } |
| |
| /** |
| * Reduce 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); |
| |
| /** |
| * Multiply two rationals. |
| * @param b first rational |
| * @param c second rational |
| * @return b*c |
| */ |
| AVRational av_mul_q(AVRational b, AVRational c) av_const; |
| |
| /** |
| * Divide 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; |
| |
| /** |
| * Add two rationals. |
| * @param b first rational |
| * @param c second rational |
| * @return b+c |
| */ |
| AVRational av_add_q(AVRational b, AVRational c) av_const; |
| |
| /** |
| * Subtract 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; |
| |
| /** |
| * Invert a rational. |
| * @param q value |
| * @return 1 / q |
| */ |
| static av_always_inline AVRational av_inv_q(AVRational q) |
| { |
| AVRational r = { q.den, q.num }; |
| return r; |
| } |
| |
| /** |
| * Convert a double precision floating point number to a rational. |
| * inf is expressed as {1,0} or {-1,0} depending on the sign. |
| * |
| * @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 q than q2, -1 if q2 is nearer |
| * than q1, 0 if they have the same distance. |
| */ |
| int av_nearer_q(AVRational q, AVRational q1, AVRational q2); |
| |
| /** |
| * Find the nearest value in q_list to 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); |
| |
| /** |
| * Converts a AVRational to a IEEE 32bit float. |
| * |
| * The float is returned in a uint32_t and its value is platform indepenant. |
| */ |
| uint32_t av_q2intfloat(AVRational q); |
| |
| /** |
| * @} |
| */ |
| |
| #endif /* AVUTIL_RATIONAL_H */ |