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
130
131
|
/*
* 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 "attributes.h"
/**
* rational number numerator/denominator
*/
typedef struct AVRational{
int num; ///< numerator
int den; ///< denominator
} AVRational;
/**
* Compare 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 ^ a.den ^ b.den)>>63)|1;
else return 0;
}
/**
* 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;
/**
* 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);
#endif /* AVUTIL_RATIONAL_H */
|
