2 * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of Libav.
6 * Libav 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.
11 * Libav 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.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 #ifndef AVUTIL_MATHEMATICS_H
22 #define AVUTIL_MATHEMATICS_H
26 #include "attributes.h"
30 #define M_LOG2_10 3.32192809488736234787 /* log_2 10 */
33 #define M_PHI 1.61803398874989484820 /* phi / golden ratio */
39 #define INFINITY (1.0/0.0)
43 * @addtogroup lavu_math
49 AV_ROUND_ZERO = 0, ///< Round toward zero.
50 AV_ROUND_INF = 1, ///< Round away from zero.
51 AV_ROUND_DOWN = 2, ///< Round toward -infinity.
52 AV_ROUND_UP = 3, ///< Round toward +infinity.
53 AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero.
57 * Return the greatest common divisor of a and b.
58 * If both a and b are 0 or either or both are <0 then behavior is
61 int64_t av_const av_gcd(int64_t a, int64_t b);
64 * Rescale a 64-bit integer with rounding to nearest.
65 * A simple a*b/c isn't possible as it can overflow.
67 int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;
70 * Rescale a 64-bit integer with specified rounding.
71 * A simple a*b/c isn't possible as it can overflow.
73 int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;
76 * Rescale a 64-bit integer by 2 rational numbers.
78 int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
81 * Rescale a 64-bit integer by 2 rational numbers with specified rounding.
83 int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
84 enum AVRounding) av_const;
87 * Compare 2 timestamps each in its own timebases.
88 * The result of the function is undefined if one of the timestamps
89 * is outside the int64_t range when represented in the others timebase.
90 * @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
92 int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
95 * Compare 2 integers modulo mod.
96 * That is we compare integers a and b for which only the least
97 * significant log2(mod) bits are known.
99 * @param mod must be a power of 2
100 * @return a negative value if a is smaller than b
101 * a positive value if a is greater than b
104 int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);
110 #endif /* AVUTIL_MATHEMATICS_H */