Add M_SQRT2 to the constants in mathematics.h.
[libav.git] / libavutil / mathematics.h
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1/*
2 * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
3 *
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4 * This file is part of FFmpeg.
5 *
6 * FFmpeg 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
8 * License as published by the Free Software Foundation; either
b78e7197 9 * version 2.1 of the License, or (at your option) any later version.
04d7f601 10 *
b78e7197 11 * FFmpeg 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
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
b78e7197 17 * License along with FFmpeg; if not, write to the Free Software
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18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
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21#ifndef AVUTIL_MATHEMATICS_H
22#define AVUTIL_MATHEMATICS_H
c11c2bc2 23
6ef29128 24#include <stdint.h>
d1a12956 25#include <math.h>
2ed6f399 26#include "attributes.h"
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27#include "rational.h"
28
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29#ifndef M_E
30#define M_E 2.7182818284590452354 /* e */
31#endif
32#ifndef M_LN2
33#define M_LN2 0.69314718055994530942 /* log_e 2 */
34#endif
35#ifndef M_LN10
36#define M_LN10 2.30258509299404568402 /* log_e 10 */
37#endif
e4a35244 38#ifndef M_LOG2_10
94a5218c 39#define M_LOG2_10 3.32192809488736234787 /* log_2 10 */
e4a35244 40#endif
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41#ifndef M_PI
42#define M_PI 3.14159265358979323846 /* pi */
43#endif
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44#ifndef M_SQRT1_2
45#define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
46#endif
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47#ifndef M_SQRT2
48#define M_SQRT2 1.41421356237309504880 /* sqrt(2) */
49#endif
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50#ifndef NAN
51#define NAN (0.0/0.0)
52#endif
53#ifndef INFINITY
54#define INFINITY (1.0/0.0)
55#endif
d1a12956 56
c11c2bc2 57enum AVRounding {
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58 AV_ROUND_ZERO = 0, ///< Round toward zero.
59 AV_ROUND_INF = 1, ///< Round away from zero.
60 AV_ROUND_DOWN = 2, ///< Round toward -infinity.
61 AV_ROUND_UP = 3, ///< Round toward +infinity.
62 AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero.
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63};
64
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65/**
66 * Returns the greatest common divisor of a and b.
bac24dd2 67 * If both a and b are 0 or either or both are <0 then behavior is
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68 * undefined.
69 */
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70int64_t av_const av_gcd(int64_t a, int64_t b);
71
c11c2bc2 72/**
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73 * Rescales a 64-bit integer with rounding to nearest.
74 * A simple a*b/c isn't possible as it can overflow.
c11c2bc2 75 */
85074d3c 76int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;
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77
78/**
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79 * Rescales a 64-bit integer with specified rounding.
80 * A simple a*b/c isn't possible as it can overflow.
c11c2bc2 81 */
85074d3c 82int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;
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83
84/**
89c9ff50 85 * Rescales a 64-bit integer by 2 rational numbers.
c11c2bc2 86 */
85074d3c 87int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
c11c2bc2 88
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89/**
90 * Compares 2 timestamps each in its own timebases.
91 * The result of the function is undefined if one of the timestamps
92 * is outside the int64_t range when represented in the others timebase.
32e543f8 93 * @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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94 */
95int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
96
97
98790382 98#endif /* AVUTIL_MATHEMATICS_H */