| 1 | /*
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| 2 | * Rational numbers
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| 3 | * Copyright (c) 2003 Michael Niedermayer <[email protected]>
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| 4 | *
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| 5 | * This file is part of FFmpeg.
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| 6 | *
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| 7 | * FFmpeg is free software; you can redistribute it and/or
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| 8 | * modify it under the terms of the GNU Lesser General Public
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| 9 | * License as published by the Free Software Foundation; either
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| 10 | * version 2.1 of the License, or (at your option) any later version.
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| 11 | *
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| 12 | * FFmpeg is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 15 | * Lesser General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU Lesser General Public
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| 18 | * License along with FFmpeg; if not, write to the Free Software
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| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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| 20 | */
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| 21 |
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| 22 | /**
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| 23 | * @file rational.h
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| 24 | * Rational numbers.
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| 25 | * @author Michael Niedermayer <[email protected]>
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| 26 | */
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| 27 |
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| 28 | #ifndef RATIONAL_H
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| 29 | #define RATIONAL_H
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| 30 |
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| 31 | #include <stdint.h>
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| 32 |
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| 33 | /**
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| 34 | * Rational number num/den.
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| 35 | */
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| 36 | typedef struct AVRational{
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| 37 | int num; ///< numerator
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| 38 | int den; ///< denominator
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| 39 | } AVRational;
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| 40 |
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| 41 | /**
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| 42 | * Compare two rationals.
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| 43 | * @param a first rational
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| 44 | * @param b second rational
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| 45 | * @return 0 if a==b, 1 if a>b and -1 if a<b.
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| 46 | */
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| 47 | static inline int av_cmp_q(AVRational a, AVRational b){
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| 48 | const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den;
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| 49 |
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| 50 | if(tmp) return (tmp>>63)|1;
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| 51 | else return 0;
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| 52 | }
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| 53 |
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| 54 | /**
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| 55 | * Rational to double conversion.
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| 56 | * @param a rational to convert
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| 57 | * @return (double) a
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| 58 | */
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| 59 | static inline double av_q2d(AVRational a){
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| 60 | return a.num / (double) a.den;
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| 61 | }
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| 62 |
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| 63 | /**
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| 64 | * Reduce a fraction.
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| 65 | * This is useful for framerate calculations.
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| 66 | * @param dst_nom destination numerator
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| 67 | * @param dst_den destination denominator
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| 68 | * @param nom source numerator
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| 69 | * @param den source denominator
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| 70 | * @param max the maximum allowed for dst_nom & dst_den
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| 71 | * @return 1 if exact, 0 otherwise
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| 72 | */
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| 73 | int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max);
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| 74 |
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| 75 | /**
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| 76 | * Multiplies two rationals.
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| 77 | * @param b first rational.
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| 78 | * @param c second rational.
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| 79 | * @return b*c.
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| 80 | */
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| 81 | AVRational av_mul_q(AVRational b, AVRational c);
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| 82 |
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| 83 | /**
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| 84 | * Divides one rational by another.
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| 85 | * @param b first rational.
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| 86 | * @param c second rational.
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| 87 | * @return b/c.
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| 88 | */
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| 89 | AVRational av_div_q(AVRational b, AVRational c);
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| 90 |
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| 91 | /**
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| 92 | * Adds two rationals.
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| 93 | * @param b first rational.
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| 94 | * @param c second rational.
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| 95 | * @return b+c.
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| 96 | */
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| 97 | AVRational av_add_q(AVRational b, AVRational c);
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| 98 |
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| 99 | /**
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| 100 | * Subtracts one rational from another.
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| 101 | * @param b first rational.
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| 102 | * @param c second rational.
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| 103 | * @return b-c.
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| 104 | */
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| 105 | AVRational av_sub_q(AVRational b, AVRational c);
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| 106 |
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| 107 | /**
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| 108 | * Converts a double precision floating point number to a rational.
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| 109 | * @param d double to convert
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| 110 | * @param max the maximum allowed numerator and denominator
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| 111 | * @return (AVRational) d.
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| 112 | */
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| 113 | AVRational av_d2q(double d, int max);
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| 114 |
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| 115 | #endif // RATIONAL_H
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