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 */ |
165 | |