Statistics
| Branch: | Revision:

ffmpeg / libavutil / mathematics.h @ 65db0587

History | View | Annotate | Download (3.41 KB)

1
/*
2
 * copyright (c) 2005 Michael Niedermayer <michaelni@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

    
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
38
#ifndef M_LOG2_10
39
#define M_LOG2_10      3.32192809488736234787  /* log_2 10 */
40
#endif
41
#ifndef M_PI
42
#define M_PI           3.14159265358979323846  /* pi */
43
#endif
44
#ifndef M_SQRT1_2
45
#define M_SQRT1_2      0.70710678118654752440  /* 1/sqrt(2) */
46
#endif
47
#ifndef M_SQRT2
48
#define M_SQRT2        1.41421356237309504880  /* sqrt(2) */
49
#endif
50
#ifndef NAN
51
#define NAN            (0.0/0.0)
52
#endif
53
#ifndef INFINITY
54
#define INFINITY       (1.0/0.0)
55
#endif
56

    
57
enum AVRounding {
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.
63
};
64

    
65
/**
66
 * Returns the greatest common divisor of a and b.
67
 * If both a and b are 0 or either or both are <0 then behavior is
68
 * undefined.
69
 */
70
int64_t av_const av_gcd(int64_t a, int64_t b);
71

    
72
/**
73
 * Rescales a 64-bit integer with rounding to nearest.
74
 * A simple a*b/c isn't possible as it can overflow.
75
 */
76
int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;
77

    
78
/**
79
 * Rescales a 64-bit integer with specified rounding.
80
 * A simple a*b/c isn't possible as it can overflow.
81
 */
82
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;
83

    
84
/**
85
 * Rescales a 64-bit integer by 2 rational numbers.
86
 */
87
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
88

    
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.
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
94
 */
95
int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
96

    
97
/**
98
 * Compare 2 integers modulo mod.
99
 * That is we compare integers a and b for which only the least significant log2(mod) bits are known
100
 * @param mod must be a power of 2
101
 * @returns a negative value if a is smaller than b
102
 *          a positiv  value if a is greater than b
103
 *          0                if a equals          b
104
 */
105
int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);
106

    
107
#endif /* AVUTIL_MATHEMATICS_H */