1 /* 2 * copyright (c) 2005-2012 Michael Niedermayer <michaelni (at) gmx.at> 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21 #ifndef AVUTIL_MATHEMATICS_H 22 #define AVUTIL_MATHEMATICS_H 23 24 #include <stdint.h> 25 #include <math.h> 26 #include "attributes.h" 27 #include "rational.h" 28 #include "intfloat.h" 29 30 #ifndef M_E 31 #define M_E 2.7182818284590452354 /* e */ 32 #endif 33 #ifndef M_LN2 34 #define M_LN2 0.69314718055994530942 /* log_e 2 */ 35 #endif 36 #ifndef M_LN10 37 #define M_LN10 2.30258509299404568402 /* log_e 10 */ 38 #endif 39 #ifndef M_LOG2_10 40 #define M_LOG2_10 3.32192809488736234787 /* log_2 10 */ 41 #endif 42 #ifndef M_PHI 43 #define M_PHI 1.61803398874989484820 /* phi / golden ratio */ 44 #endif 45 #ifndef M_PI 46 #define M_PI 3.14159265358979323846 /* pi */ 47 #endif 48 #ifndef M_SQRT1_2 49 #define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */ 50 #endif 51 #ifndef M_SQRT2 52 #define M_SQRT2 1.41421356237309504880 /* sqrt(2) */ 53 #endif 54 #ifndef NAN 55 #define NAN av_int2float(0x7fc00000) 56 #endif 57 #ifndef INFINITY 58 #define INFINITY av_int2float(0x7f800000) 59 #endif 60 61 /** 62 * @addtogroup lavu_math 63 * @{ 64 */ 65 66 67 enum AVRounding { 68 AV_ROUND_ZERO = 0, ///< Round toward zero. 69 AV_ROUND_INF = 1, ///< Round away from zero. 70 AV_ROUND_DOWN = 2, ///< Round toward -infinity. 71 AV_ROUND_UP = 3, ///< Round toward +infinity. 72 AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero. 73 AV_ROUND_PASS_MINMAX = 8192, ///< Flag to pass INT64_MIN/MAX through instead of rescaling, this avoids special cases for AV_NOPTS_VALUE 74 }; 75 76 /** 77 * Return the greatest common divisor of a and b. 78 * If both a and b are 0 or either or both are <0 then behavior is 79 * undefined. 80 */ 81 int64_t av_const av_gcd(int64_t a, int64_t b); 82 83 /** 84 * Rescale a 64-bit integer with rounding to nearest. 85 * A simple a*b/c isn't possible as it can overflow. 86 */ 87 int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const; 88 89 /** 90 * Rescale a 64-bit integer with specified rounding. 91 * A simple a*b/c isn't possible as it can overflow. 92 * 93 * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is 94 * INT64_MIN or INT64_MAX then a is passed through unchanged. 95 */ 96 int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const; 97 98 /** 99 * Rescale a 64-bit integer by 2 rational numbers. 100 */ 101 int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const; 102 103 /** 104 * Rescale a 64-bit integer by 2 rational numbers with specified rounding. 105 * 106 * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is 107 * INT64_MIN or INT64_MAX then a is passed through unchanged. 108 */ 109 int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq, 110 enum AVRounding) av_const; 111 112 /** 113 * Compare 2 timestamps each in its own timebases. 114 * The result of the function is undefined if one of the timestamps 115 * is outside the int64_t range when represented in the others timebase. 116 * @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 117 */ 118 int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b); 119 120 /** 121 * Compare 2 integers modulo mod. 122 * That is we compare integers a and b for which only the least 123 * significant log2(mod) bits are known. 124 * 125 * @param mod must be a power of 2 126 * @return a negative value if a is smaller than b 127 * a positive value if a is greater than b 128 * 0 if a equals b 129 */ 130 int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod); 131 132 /** 133 * Rescale a timestamp while preserving known durations. 134 * 135 * @param in_ts Input timestamp 136 * @param in_tb Input timesbase 137 * @param fs_tb Duration and *last timebase 138 * @param duration duration till the next call 139 * @param out_tb Output timesbase 140 */ 141 int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts, AVRational fs_tb, int duration, int64_t *last, AVRational out_tb); 142 143 /** 144 * @} 145 */ 146 147 #endif /* AVUTIL_MATHEMATICS_H */ 148
