Imported Debian version 2.5.0~trusty1.1
[deb_ffmpeg.git] / ffmpeg / libavutil / mathematics.h
1 /*
2 * copyright (c) 2005-2012 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 #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_PI_2
49 #define M_PI_2 1.57079632679489661923 /* pi/2 */
50 #endif
51 #ifndef M_SQRT1_2
52 #define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
53 #endif
54 #ifndef M_SQRT2
55 #define M_SQRT2 1.41421356237309504880 /* sqrt(2) */
56 #endif
57 #ifndef NAN
58 #define NAN av_int2float(0x7fc00000)
59 #endif
60 #ifndef INFINITY
61 #define INFINITY av_int2float(0x7f800000)
62 #endif
63
64 /**
65 * @addtogroup lavu_math
66 * @{
67 */
68
69
70 enum AVRounding {
71 AV_ROUND_ZERO = 0, ///< Round toward zero.
72 AV_ROUND_INF = 1, ///< Round away from zero.
73 AV_ROUND_DOWN = 2, ///< Round toward -infinity.
74 AV_ROUND_UP = 3, ///< Round toward +infinity.
75 AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero.
76 AV_ROUND_PASS_MINMAX = 8192, ///< Flag to pass INT64_MIN/MAX through instead of rescaling, this avoids special cases for AV_NOPTS_VALUE
77 };
78
79 /**
80 * Return the greatest common divisor of a and b.
81 * If both a and b are 0 or either or both are <0 then behavior is
82 * undefined.
83 */
84 int64_t av_const av_gcd(int64_t a, int64_t b);
85
86 /**
87 * Rescale a 64-bit integer with rounding to nearest.
88 * A simple a*b/c isn't possible as it can overflow.
89 */
90 int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;
91
92 /**
93 * Rescale a 64-bit integer with specified rounding.
94 * A simple a*b/c isn't possible as it can overflow.
95 *
96 * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
97 * INT64_MIN or INT64_MAX then a is passed through unchanged.
98 */
99 int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;
100
101 /**
102 * Rescale a 64-bit integer by 2 rational numbers.
103 */
104 int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
105
106 /**
107 * Rescale a 64-bit integer by 2 rational numbers with specified rounding.
108 *
109 * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
110 * INT64_MIN or INT64_MAX then a is passed through unchanged.
111 */
112 int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
113 enum AVRounding) av_const;
114
115 /**
116 * Compare 2 timestamps each in its own timebases.
117 * The result of the function is undefined if one of the timestamps
118 * is outside the int64_t range when represented in the others timebase.
119 * @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
120 */
121 int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
122
123 /**
124 * Compare 2 integers modulo mod.
125 * That is we compare integers a and b for which only the least
126 * significant log2(mod) bits are known.
127 *
128 * @param mod must be a power of 2
129 * @return a negative value if a is smaller than b
130 * a positive value if a is greater than b
131 * 0 if a equals b
132 */
133 int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);
134
135 /**
136 * Rescale a timestamp while preserving known durations.
137 *
138 * @param in_ts Input timestamp
139 * @param in_tb Input timebase
140 * @param fs_tb Duration and *last timebase
141 * @param duration duration till the next call
142 * @param out_tb Output timebase
143 */
144 int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts, AVRational fs_tb, int duration, int64_t *last, AVRational out_tb);
145
146 /**
147 * Add a value to a timestamp.
148 *
149 * This function guarantees that when the same value is repeatly added that
150 * no accumulation of rounding errors occurs.
151 *
152 * @param ts Input timestamp
153 * @param ts_tb Input timestamp timebase
154 * @param inc value to add to ts
155 * @param inc_tb inc timebase
156 */
157 int64_t av_add_stable(AVRational ts_tb, int64_t ts, AVRational inc_tb, int64_t inc);
158
159
160 /**
161 * @}
162 */
163
164 #endif /* AVUTIL_MATHEMATICS_H */