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comparison lib/libavutil/mathematics.h @ 2134:992d2e6f907d

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preparation for libavcodec
author zipi
date Tue, 31 Dec 2013 14:52:14 +0000
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2133:e378232bfd36 2134:992d2e6f907d
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_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 */