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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