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a1245d5ca1
Some compilers, MSVC among them, don't recognize the divisions by zero as meaning infinity/nan. These macros should, according to the standard, expand to constant expressions, but this shouldn't matter for our usage. Signed-off-by: Martin Storsjö <martin@martin.st>
112 lines
3.3 KiB
C
112 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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#include "intfloat.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 av_int2float(0x7fc00000)
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#endif
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#ifndef INFINITY
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#define INFINITY av_int2float(0x7f800000)
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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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