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1	5ff85f1d	Michael Niedermayer	/*
2	89c9ff50	Diego Biurrun	* rational numbers
3	5ff85f1d	Michael Niedermayer	* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4			*
5	b78e7197	Diego Biurrun	* This file is part of FFmpeg.
6			*
7			* FFmpeg is free software; you can redistribute it and/or
8	5ff85f1d	Michael Niedermayer	* modify it under the terms of the GNU Lesser General Public
9			* License as published by the Free Software Foundation; either
10	b78e7197	Diego Biurrun	* version 2.1 of the License, or (at your option) any later version.
11	5ff85f1d	Michael Niedermayer	*
12	b78e7197	Diego Biurrun	* FFmpeg is distributed in the hope that it will be useful,
13	5ff85f1d	Michael Niedermayer	* but WITHOUT ANY WARRANTY; without even the implied warranty of
14			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15			* Lesser General Public License for more details.
16			*
17			* You should have received a copy of the GNU Lesser General Public
18	b78e7197	Diego Biurrun	* License along with FFmpeg; if not, write to the Free Software
19	5509bffa	Diego Biurrun	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20	5ff85f1d	Michael Niedermayer	*/
21	115329f1	Diego Biurrun
22	5ff85f1d	Michael Niedermayer	/**
23	bad5537e	Diego Biurrun	* @file libavutil/rational.h
24	89c9ff50	Diego Biurrun	* rational numbers
25	5ff85f1d	Michael Niedermayer	* @author Michael Niedermayer <michaelni@gmx.at>
26			*/
27
28	98790382	Stefano Sabatini	#ifndef AVUTIL_RATIONAL_H
29			#define AVUTIL_RATIONAL_H
30	5ff85f1d	Michael Niedermayer
31	99545457	Måns Rullgård	#include <stdint.h>
32	85074d3c	Zuxy Meng	#include "common.h"
33	99545457	Måns Rullgård
34	5c07b9e9	Michael Niedermayer	/**
35	89c9ff50	Diego Biurrun	* rational number numerator/denominator
36	5c07b9e9	Michael Niedermayer	*/
37	5ff85f1d	Michael Niedermayer	typedef struct AVRational{
38	5c07b9e9	Michael Niedermayer	int num; ///< numerator
39			int den; ///< denominator
40	5ff85f1d	Michael Niedermayer	} AVRational;
41
42	5c07b9e9	Michael Niedermayer	/**
43	89c9ff50	Diego Biurrun	* Compares two rationals.
44	1c95ef8b	Dujardin Bernard	* @param a first rational
45			* @param b second rational
46	89c9ff50	Diego Biurrun	* @return 0 if a==b, 1 if a>b and -1 if a<b
47	5c07b9e9	Michael Niedermayer	*/
48	5ff85f1d	Michael Niedermayer	static inline int av_cmp_q(AVRational a, AVRational b){
49			const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den;
50
51	5c07b9e9	Michael Niedermayer	if(tmp) return (tmp>>63)\|1;
52			else return 0;
53	5ff85f1d	Michael Niedermayer	}
54
55	5c07b9e9	Michael Niedermayer	/**
56	89c9ff50	Diego Biurrun	* Converts rational to double.
57	1c95ef8b	Dujardin Bernard	* @param a rational to convert
58			* @return (double) a
59	5c07b9e9	Michael Niedermayer	*/
60	5ff85f1d	Michael Niedermayer	static inline double av_q2d(AVRational a){
61			return a.num / (double) a.den;
62			}
63
64	c11c2bc2	Alexander Strasser	/**
65	89c9ff50	Diego Biurrun	* Reduces a fraction.
66	804de96a	Diego Biurrun	* This is useful for framerate calculations.
67	674bd4f6	Diego Biurrun	* @param dst_num destination numerator
68	1c95ef8b	Dujardin Bernard	* @param dst_den destination denominator
69	674bd4f6	Diego Biurrun	* @param num source numerator
70	1c95ef8b	Dujardin Bernard	* @param den source denominator
71	674bd4f6	Diego Biurrun	* @param max the maximum allowed for dst_num & dst_den
72	c11c2bc2	Alexander Strasser	* @return 1 if exact, 0 otherwise
73			*/
74	674bd4f6	Diego Biurrun	int av_reduce(int dst_num, int dst_den, int64_t num, int64_t den, int64_t max);
75	c11c2bc2	Alexander Strasser
76	0b006599	Dujardin Bernard	/**
77			* Multiplies two rationals.
78	89c9ff50	Diego Biurrun	* @param b first rational
79			* @param c second rational
80			* @return b*c
81	0b006599	Dujardin Bernard	*/
82	85074d3c	Zuxy Meng	AVRational av_mul_q(AVRational b, AVRational c) av_const;
83	0b006599	Dujardin Bernard
84			/**
85	ca9049ef	Guillaume Poirier	* Divides one rational by another.
86	89c9ff50	Diego Biurrun	* @param b first rational
87			* @param c second rational
88			* @return b/c
89	0b006599	Dujardin Bernard	*/
90	85074d3c	Zuxy Meng	AVRational av_div_q(AVRational b, AVRational c) av_const;
91	0b006599	Dujardin Bernard
92			/**
93			* Adds two rationals.
94	89c9ff50	Diego Biurrun	* @param b first rational
95			* @param c second rational
96			* @return b+c
97	0b006599	Dujardin Bernard	*/
98	85074d3c	Zuxy Meng	AVRational av_add_q(AVRational b, AVRational c) av_const;
99	0b006599	Dujardin Bernard
100			/**
101	ca9049ef	Guillaume Poirier	* Subtracts one rational from another.
102	89c9ff50	Diego Biurrun	* @param b first rational
103			* @param c second rational
104			* @return b-c
105	0b006599	Dujardin Bernard	*/
106	85074d3c	Zuxy Meng	AVRational av_sub_q(AVRational b, AVRational c) av_const;
107	0b006599	Dujardin Bernard
108			/**
109			* Converts a double precision floating point number to a rational.
110			* @param d double to convert
111			* @param max the maximum allowed numerator and denominator
112	89c9ff50	Diego Biurrun	* @return (AVRational) d
113	0b006599	Dujardin Bernard	*/
114	85074d3c	Zuxy Meng	AVRational av_d2q(double d, int max) av_const;
115	5ff85f1d	Michael Niedermayer
116	05b90fc0	Stefano Sabatini	/**
117	bf7e799c	Stefano Sabatini	* @return 1 if q1 is nearer to q than q2, -1 if q2 is nearer
118			* than q1, 0 if they have the same distance.
119	05b90fc0	Stefano Sabatini	*/
120			int av_nearer_q(AVRational q, AVRational q1, AVRational q2);
121
122			/**
123	bf7e799c	Stefano Sabatini	* Finds the nearest value in q_list to q.
124	05b90fc0	Stefano Sabatini	* @param q_list an array of rationals terminated by {0, 0}
125			* @return the index of the nearest value found in the array
126			*/
127			int av_find_nearest_q_idx(AVRational q, const AVRational* q_list);
128
129	98790382	Stefano Sabatini	#endif /* AVUTIL_RATIONAL_H */