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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 libavutil/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 numerator/denominator | |
36 */ | |
37 typedef struct AVRational{ | |
38 int num; ///< numerator | |
39 int den; ///< denominator | |
40 } AVRational; | |
41 | |
42 /** | |
43 * Compares 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 * Converts rational to double. | |
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 * Reduces a fraction. | |
66 * This is useful for framerate calculations. | |
67 * @param dst_num destination numerator | |
68 * @param dst_den destination denominator | |
69 * @param num source numerator | |
70 * @param den source denominator | |
71 * @param max the maximum allowed for dst_num & dst_den | |
72 * @return 1 if exact, 0 otherwise | |
73 */ | |
74 int av_reduce(int *dst_num, int *dst_den, int64_t num, 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 /** | |
117 * @return 1 if \q1 is nearer to \p q than \p q2, -1 if \p q2 is nearer | |
118 * than \p q1, 0 if they have the same distance. | |
119 */ | |
120 int av_nearer_q(AVRational q, AVRational q1, AVRational q2); | |
121 | |
122 /** | |
123 * Finds the nearest value in \p q_list to \p q. | |
124 * @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 #endif /* AVUTIL_RATIONAL_H */ | |
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