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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 */ |