ffmpeg.libavutil.mathematics source code

1 /*
2  * copyright (c) 2005 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 module ffmpeg.libavutil.mathematics;
22 
23 import std.stdint;
24 
25 import ffmpeg.libavutil.rational;
26 import ffmpeg.libavutil.intfloat;
27 
28 enum M_E          =  2.7182818284590452354;   /* e */
29 enum M_LN2        =  0.69314718055994530942;  /* log_e 2 */
30 enum M_LN10       =  2.30258509299404568402;  /* log_e 10 */
31 enum M_LOG2_10    =  3.32192809488736234787;  /* log_2 10 */
32 enum M_PHI        =  1.61803398874989484820;   /* phi / golden ratio */
33 enum M_PI         =  3.14159265358979323846;  /* pi */
34 enum M_PI_2       =  1.57079632679489661923;  /* pi/2 */
35 enum M_SQRT1_2    =  0.70710678118654752440;  /* 1/sqrt(2) */
36 enum M_SQRT2      =  1.41421356237309504880; /* sqrt(2) */
37 enum NAN          =  av_int2float(0x7fc00000);
38 enum INFINITY     =  av_int2float(0x7f800000);
39 
40 @nogc nothrow extern(C):
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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  * Compute the greatest common divisor of a and b.
81  *
82  * @return gcd of a and b up to sign; if a >= 0 and b >= 0, return value is >= 0;
83  * if a == 0 and b == 0, returns 0.
84  */
85 int64_t av_gcd(int64_t a, int64_t b);
86 
87 /**
88  * Rescale a 64-bit integer with rounding to nearest.
89  * A simple a*b/c isn't possible as it can overflow.
90  */
91 int64_t av_rescale(int64_t a, int64_t b, int64_t c);
92 
93 /**
94  * Rescale a 64-bit integer with specified rounding.
95  * A simple a*b/c isn't possible as it can overflow.
96  *
97  * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
98  *         INT64_MIN or INT64_MAX then a is passed through unchanged.
99  */
100 int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, AVRounding);
101 
102 /**
103  * Rescale a 64-bit integer by 2 rational numbers.
104  */
105 int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq);
106 
107 /**
108  * Rescale a 64-bit integer by 2 rational numbers with specified rounding.
109  *
110  * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
111  *         INT64_MIN or INT64_MAX then a is passed through unchanged.
112  */
113 int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
114                          AVRounding);
115 
116 /**
117  * Compare 2 timestamps each in its own timebases.
118  * The result of the function is undefined if one of the timestamps
119  * is outside the int64_t range when represented in the others timebase.
120  * @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
121  */
122 int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
123 
124 /**
125  * Compare 2 integers modulo mod.
126  * That is we compare integers a and b for which only the least
127  * significant log2(mod) bits are known.
128  *
129  * @param mod must be a power of 2
130  * @return a negative value if a is smaller than b
131  *         a positive value if a is greater than b
132  *         0                if a equals          b
133  */
134 int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);
135 
136 /**
137  * Rescale a timestamp while preserving known durations.
138  *
139  * @param in_ts Input timestamp
140  * @param in_tb Input timesbase
141  * @param fs_tb Duration and *last timebase
142  * @param duration duration till the next call
143  * @param out_tb Output timesbase
144  */
145 int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts,  AVRational fs_tb, int duration, int64_t *last, AVRational out_tb);
146 
147 /**
148  * Add a value to a timestamp.
149  *
150  * This function guarantees that when the same value is repeatly added that
151  * no accumulation of rounding errors occurs.
152  *
153  * @param ts Input timestamp
154  * @param ts_tb Input timestamp timebase
155  * @param inc value to add to ts
156  * @param inc_tb inc timebase
157  */
158 int64_t av_add_stable(AVRational ts_tb, int64_t ts, AVRational inc_tb, int64_t inc);
159 
160 
161 /**
162  * @}
163  */
164 
165 //#endif /* AVUTIL_MATHEMATICS_H */