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78 lines
2.1 KiB
C
78 lines
2.1 KiB
C
/*
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* Rational numbers
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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*
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* This library 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 of the License, or (at your option) any later version.
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*
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* This library 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 this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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/**
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* @file rational.c
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* Rational numbers
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* @author Michael Niedermayer <michaelni@gmx.at>
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*/
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//#include <math.h>
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#include <limits.h>
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#include "common.h"
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#include "avcodec.h"
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#include "rational.h"
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/**
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* returns b*c.
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*/
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AVRational av_mul_q(AVRational b, AVRational c){
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av_reduce(&b.num, &b.den, b.num * (int64_t)c.num, b.den * (int64_t)c.den, INT_MAX);
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return b;
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}
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/**
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* returns b/c.
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*/
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AVRational av_div_q(AVRational b, AVRational c){
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av_reduce(&b.num, &b.den, b.num * (int64_t)c.den, b.den * (int64_t)c.num, INT_MAX);
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return b;
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}
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/**
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* returns b+c.
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*/
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AVRational av_add_q(AVRational b, AVRational c){
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av_reduce(&b.num, &b.den, b.num * (int64_t)c.den + c.num * (int64_t)b.den, b.den * (int64_t)c.den, INT_MAX);
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return b;
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}
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/**
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* returns b-c.
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*/
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AVRational av_sub_q(AVRational b, AVRational c){
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av_reduce(&b.num, &b.den, b.num * (int64_t)c.den - c.num * (int64_t)b.den, b.den * (int64_t)c.den, INT_MAX);
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return b;
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}
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/**
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* Converts a double precission floating point number to a AVRational.
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* @param max the maximum allowed numerator and denominator
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*/
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AVRational av_d2q(double d, int max){
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AVRational a;
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int exponent= FFMAX( (int)(log(ABS(d) + 1e-20)/log(2)), 0);
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int64_t den= 1LL << (61 - exponent);
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av_reduce(&a.num, &a.den, (int64_t)(d * den + 0.5), den, max);
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return a;
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}
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