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1 /* |
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2 * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> |
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3 * |
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4 * This file is part of Libav. |
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5 * |
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6 * Libav is free software; you can redistribute it and/or |
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7 * modify it under the terms of the GNU Lesser General Public |
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8 * License as published by the Free Software Foundation; either |
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9 * version 2.1 of the License, or (at your option) any later version. |
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10 * |
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11 * Libav is distributed in the hope that it will be useful, |
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 * Lesser General Public License for more details. |
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15 * |
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16 * You should have received a copy of the GNU Lesser General Public |
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17 * License along with Libav; if not, write to the Free Software |
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18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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19 */ |
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20 |
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21 #ifndef AVUTIL_MATHEMATICS_H |
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22 #define AVUTIL_MATHEMATICS_H |
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23 |
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24 #include <stdint.h> |
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25 #include <math.h> |
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26 #include "attributes.h" |
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27 #include "rational.h" |
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28 #include "intfloat.h" |
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29 |
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30 #ifndef M_LOG2_10 |
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31 #define M_LOG2_10 3.32192809488736234787 /* log_2 10 */ |
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32 #endif |
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33 #ifndef M_PHI |
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34 #define M_PHI 1.61803398874989484820 /* phi / golden ratio */ |
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35 #endif |
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36 #ifndef NAN |
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37 #define NAN av_int2float(0x7fc00000) |
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38 #endif |
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39 #ifndef INFINITY |
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40 #define INFINITY av_int2float(0x7f800000) |
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41 #endif |
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42 |
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43 /** |
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44 * @addtogroup lavu_math |
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45 * @{ |
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46 */ |
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47 |
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48 |
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49 enum AVRounding { |
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50 AV_ROUND_ZERO = 0, ///< Round toward zero. |
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51 AV_ROUND_INF = 1, ///< Round away from zero. |
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52 AV_ROUND_DOWN = 2, ///< Round toward -infinity. |
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53 AV_ROUND_UP = 3, ///< Round toward +infinity. |
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54 AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero. |
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55 }; |
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56 |
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57 /** |
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58 * Return the greatest common divisor of a and b. |
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59 * If both a and b are 0 or either or both are <0 then behavior is |
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60 * undefined. |
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61 */ |
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62 int64_t av_const av_gcd(int64_t a, int64_t b); |
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63 |
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64 /** |
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65 * Rescale a 64-bit integer with rounding to nearest. |
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66 * A simple a*b/c isn't possible as it can overflow. |
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67 */ |
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68 int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const; |
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69 |
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70 /** |
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71 * Rescale a 64-bit integer with specified rounding. |
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72 * A simple a*b/c isn't possible as it can overflow. |
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73 */ |
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74 int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const; |
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75 |
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76 /** |
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77 * Rescale a 64-bit integer by 2 rational numbers. |
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78 */ |
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79 int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const; |
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80 |
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81 /** |
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82 * Rescale a 64-bit integer by 2 rational numbers with specified rounding. |
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83 */ |
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84 int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq, |
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85 enum AVRounding) av_const; |
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86 |
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87 /** |
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88 * Compare 2 timestamps each in its own timebases. |
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89 * The result of the function is undefined if one of the timestamps |
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90 * is outside the int64_t range when represented in the others timebase. |
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91 * @return -1 if ts_a is before ts_b, 1 if ts_a is after ts_b or 0 if they represent the same position |
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92 */ |
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93 int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b); |
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94 |
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95 /** |
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96 * Compare 2 integers modulo mod. |
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97 * That is we compare integers a and b for which only the least |
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98 * significant log2(mod) bits are known. |
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99 * |
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100 * @param mod must be a power of 2 |
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101 * @return a negative value if a is smaller than b |
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102 * a positive value if a is greater than b |
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103 * 0 if a equals b |
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104 */ |
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105 int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod); |
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106 |
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107 /** |
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108 * @} |
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109 */ |
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110 |
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111 #endif /* AVUTIL_MATHEMATICS_H */ |