1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
/*
* 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 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);
/**
* Finds 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);
#endif /* AVUTIL_RATIONAL_H */
|
