Globally rename the header inclusion guard names.
[libav.git] / libavutil / rational.h
1 /*
2 * Rational numbers
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * 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 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file rational.h
24 * Rational numbers.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28 #ifndef AVUTIL_RATIONAL_H
29 #define AVUTIL_RATIONAL_H
30
31 #include <stdint.h>
32 #include "common.h"
33
34 /**
35 * Rational number num/den.
36 */
37 typedef struct AVRational{
38 int num; ///< numerator
39 int den; ///< denominator
40 } AVRational;
41
42 /**
43 * Compare two rationals.
44 * @param a first rational
45 * @param b second rational
46 * @return 0 if a==b, 1 if a>b and -1 if a<b.
47 */
48 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 if(tmp) return (tmp>>63)|1;
52 else return 0;
53 }
54
55 /**
56 * Rational to double conversion.
57 * @param a rational to convert
58 * @return (double) a
59 */
60 static inline double av_q2d(AVRational a){
61 return a.num / (double) a.den;
62 }
63
64 /**
65 * Reduce a fraction.
66 * This is useful for framerate calculations.
67 * @param dst_nom destination numerator
68 * @param dst_den destination denominator
69 * @param nom source numerator
70 * @param den source denominator
71 * @param max the maximum allowed for dst_nom & dst_den
72 * @return 1 if exact, 0 otherwise
73 */
74 int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max);
75
76 /**
77 * Multiplies two rationals.
78 * @param b first rational.
79 * @param c second rational.
80 * @return b*c.
81 */
82 AVRational av_mul_q(AVRational b, AVRational c) av_const;
83
84 /**
85 * Divides one rational by another.
86 * @param b first rational.
87 * @param c second rational.
88 * @return b/c.
89 */
90 AVRational av_div_q(AVRational b, AVRational c) av_const;
91
92 /**
93 * Adds two rationals.
94 * @param b first rational.
95 * @param c second rational.
96 * @return b+c.
97 */
98 AVRational av_add_q(AVRational b, AVRational c) av_const;
99
100 /**
101 * Subtracts one rational from another.
102 * @param b first rational.
103 * @param c second rational.
104 * @return b-c.
105 */
106 AVRational av_sub_q(AVRational b, AVRational c) av_const;
107
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 * @return (AVRational) d.
113 */
114 AVRational av_d2q(double d, int max) av_const;
115
116 #endif /* AVUTIL_RATIONAL_H */