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a2b186a188
While these defines are not defined by the C standard they are standardized as X/Open System Interfaces Extension. We use the appropiate _XOPEN_SOURCE define to make them available. They seem to be available on all FATE configs since the constants are used in files where mathematics.h is not included.
111 lines
3.3 KiB
C
111 lines
3.3 KiB
C
/*
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* copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVUTIL_MATHEMATICS_H
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#define AVUTIL_MATHEMATICS_H
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#include <stdint.h>
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#include <math.h>
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#include "attributes.h"
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#include "rational.h"
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#ifndef M_LOG2_10
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#define M_LOG2_10 3.32192809488736234787 /* log_2 10 */
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#endif
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#ifndef M_PHI
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#define M_PHI 1.61803398874989484820 /* phi / golden ratio */
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#endif
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#ifndef NAN
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#define NAN (0.0/0.0)
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#endif
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#ifndef INFINITY
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#define INFINITY (1.0/0.0)
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#endif
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/**
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* @addtogroup lavu_math
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* @{
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*/
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enum AVRounding {
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AV_ROUND_ZERO = 0, ///< Round toward zero.
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AV_ROUND_INF = 1, ///< Round away from zero.
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AV_ROUND_DOWN = 2, ///< Round toward -infinity.
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AV_ROUND_UP = 3, ///< Round toward +infinity.
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AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero.
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};
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/**
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* Return the greatest common divisor of a and b.
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* If both a and b are 0 or either or both are <0 then behavior is
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* undefined.
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*/
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int64_t av_const av_gcd(int64_t a, int64_t b);
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/**
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* Rescale a 64-bit integer with rounding to nearest.
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* A simple a*b/c isn't possible as it can overflow.
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*/
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int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;
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/**
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* Rescale a 64-bit integer with specified rounding.
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* A simple a*b/c isn't possible as it can overflow.
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*/
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int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;
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/**
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* Rescale a 64-bit integer by 2 rational numbers.
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*/
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int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
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/**
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* Rescale a 64-bit integer by 2 rational numbers with specified rounding.
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*/
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int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
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enum AVRounding) av_const;
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/**
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* Compare 2 timestamps each in its own timebases.
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* The result of the function is undefined if one of the timestamps
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* is outside the int64_t range when represented in the others timebase.
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* @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
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*/
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int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
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/**
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* Compare 2 integers modulo mod.
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* That is we compare integers a and b for which only the least
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* significant log2(mod) bits are known.
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*
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* @param mod must be a power of 2
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* @return a negative value if a is smaller than b
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* a positive value if a is greater than b
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* 0 if a equals b
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*/
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int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);
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/**
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* @}
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*/
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#endif /* AVUTIL_MATHEMATICS_H */
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