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129 lines
3.4 KiB
129 lines
3.4 KiB
/* |
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* rational numbers |
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/** |
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* @file |
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* rational numbers |
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* @author Michael Niedermayer <michaelni@gmx.at> |
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*/ |
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#ifndef AVUTIL_RATIONAL_H |
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#define AVUTIL_RATIONAL_H |
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#include <msc_stdint.h> |
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#include "attributes.h" |
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/** |
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* rational number numerator/denominator |
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*/ |
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typedef struct AVRational{ |
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int num; ///< numerator |
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int den; ///< denominator |
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} AVRational; |
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/** |
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* Compares two rationals. |
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* @param a first rational |
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* @param b second rational |
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* @return 0 if a==b, 1 if a>b and -1 if a<b |
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*/ |
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static inline int av_cmp_q(AVRational a, AVRational b){ |
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const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den; |
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if(tmp) return (tmp>>63)|1; |
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else return 0; |
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} |
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/** |
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* Converts rational to double. |
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* @param a rational to convert |
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* @return (double) a |
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*/ |
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static inline double av_q2d(AVRational a){ |
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return a.num / (double) a.den; |
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} |
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/** |
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* Reduces a fraction. |
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* This is useful for framerate calculations. |
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* @param dst_num destination numerator |
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* @param dst_den destination denominator |
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* @param num source numerator |
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* @param den source denominator |
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* @param max the maximum allowed for dst_num & dst_den |
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* @return 1 if exact, 0 otherwise |
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*/ |
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int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max); |
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/** |
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* Multiplies two rationals. |
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* @param b first rational |
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* @param c second rational |
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* @return b*c |
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*/ |
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AVRational av_mul_q(AVRational b, AVRational c) av_const; |
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/** |
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* Divides one rational by another. |
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* @param b first rational |
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* @param c second rational |
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* @return b/c |
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*/ |
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AVRational av_div_q(AVRational b, AVRational c) av_const; |
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/** |
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* Adds two rationals. |
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* @param b first rational |
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* @param c second rational |
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* @return b+c |
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*/ |
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AVRational av_add_q(AVRational b, AVRational c) av_const; |
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/** |
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* Subtracts one rational from another. |
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* @param b first rational |
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* @param c second rational |
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* @return b-c |
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*/ |
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AVRational av_sub_q(AVRational b, AVRational c) av_const; |
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/** |
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* Converts a double precision floating point number to a rational. |
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* @param d double to convert |
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* @param max the maximum allowed numerator and denominator |
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* @return (AVRational) d |
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*/ |
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AVRational av_d2q(double d, int max) av_const; |
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/** |
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* @return 1 if q1 is nearer to q than q2, -1 if q2 is nearer |
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* than q1, 0 if they have the same distance. |
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*/ |
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int av_nearer_q(AVRational q, AVRational q1, AVRational q2); |
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/** |
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* Finds the nearest value in q_list to q. |
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* @param q_list an array of rationals terminated by {0, 0} |
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* @return the index of the nearest value found in the array |
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*/ |
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int av_find_nearest_q_idx(AVRational q, const AVRational* q_list); |
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#endif /* AVUTIL_RATIONAL_H */
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