aboutsummaryrefslogtreecommitdiffstats
path: root/libavutil/mathematics.h
blob: 71f0392218d71fdbf6fc630681949a5ecaaf9298 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/*
 * copyright (c) 2005-2012 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVUTIL_MATHEMATICS_H
#define AVUTIL_MATHEMATICS_H

#include <stdint.h>
#include <math.h>
#include "attributes.h"
#include "rational.h"
#include "intfloat.h"

#ifndef M_E
#define M_E            2.7182818284590452354   /* e */
#endif
#ifndef M_LN2
#define M_LN2          0.69314718055994530942  /* log_e 2 */
#endif
#ifndef M_LN10
#define M_LN10         2.30258509299404568402  /* log_e 10 */
#endif
#ifndef M_LOG2_10
#define M_LOG2_10      3.32192809488736234787  /* log_2 10 */
#endif
#ifndef M_PHI
#define M_PHI          1.61803398874989484820   /* phi / golden ratio */
#endif
#ifndef M_PI
#define M_PI           3.14159265358979323846  /* pi */
#endif
#ifndef M_SQRT1_2
#define M_SQRT1_2      0.70710678118654752440  /* 1/sqrt(2) */
#endif
#ifndef M_SQRT2
#define M_SQRT2        1.41421356237309504880  /* sqrt(2) */
#endif
#ifndef NAN
#define NAN            av_int2float(0x7fc00000)
#endif
#ifndef INFINITY
#define INFINITY       av_int2float(0x7f800000)
#endif

/**
 * @addtogroup lavu_math
 * @{
 */


enum AVRounding {
    AV_ROUND_ZERO     = 0, ///< Round toward zero.
    AV_ROUND_INF      = 1, ///< Round away from zero.
    AV_ROUND_DOWN     = 2, ///< Round toward -infinity.
    AV_ROUND_UP       = 3, ///< Round toward +infinity.
    AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero.
    AV_ROUND_PASS_MINMAX = 8192, ///< Flag to pass INT64_MIN/MAX through instead of rescaling, this avoids special cases for AV_NOPTS_VALUE
};

/**
 * Return the greatest common divisor of a and b.
 * If both a and b are 0 or either or both are <0 then behavior is
 * undefined.
 */
int64_t av_const av_gcd(int64_t a, int64_t b);

/**
 * Rescale a 64-bit integer with rounding to nearest.
 * A simple a*b/c isn't possible as it can overflow.
 */
int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;

/**
 * Rescale a 64-bit integer with specified rounding.
 * A simple a*b/c isn't possible as it can overflow.
 *
 * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
 *         INT64_MIN or INT64_MAX then a is passed through unchanged.
 */
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;

/**
 * Rescale a 64-bit integer by 2 rational numbers.
 */
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;

/**
 * Rescale a 64-bit integer by 2 rational numbers with specified rounding.
 *
 * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
 *         INT64_MIN or INT64_MAX then a is passed through unchanged.
 */
int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
                         enum AVRounding) av_const;

/**
 * Compare 2 timestamps each in its own timebases.
 * The result of the function is undefined if one of the timestamps
 * is outside the int64_t range when represented in the others timebase.
 * @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
 */
int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);

/**
 * Compare 2 integers modulo mod.
 * That is we compare integers a and b for which only the least
 * significant log2(mod) bits are known.
 *
 * @param mod must be a power of 2
 * @return a negative value if a is smaller than b
 *         a positive value if a is greater than b
 *         0                if a equals          b
 */
int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);

/**
 * Rescale a timestamp while preserving known durations.
 *
 * @param in_ts Input timestamp
 * @param in_tb Input timesbase
 * @param fs_tb Duration and *last timebase
 * @param duration duration till the next call
 * @param out_tb Output timesbase
 */
int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts,  AVRational fs_tb, int duration, int64_t *last, AVRational out_tb);

/**
 * @}
 */

#endif /* AVUTIL_MATHEMATICS_H */