kicad/common/math/math_util.cpp

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/*
* This program source code file is part of KICAD, a free EDA CAD application.
*
* Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
* Copyright (C) CERN
* @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include <cmath>
#include <cstdlib>
#include <climits>
#include <math/math_util.h>
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template <>
int rescale( int aNumerator, int aValue, int aDenominator )
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{
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return (int) ( (int64_t) aNumerator * (int64_t) aValue / (int64_t) aDenominator );
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}
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template <>
int64_t rescale( int64_t aNumerator, int64_t aValue, int64_t aDenominator )
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{
int64_t r = 0;
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int64_t sign = ( ( aNumerator < 0 ) ? -1 : 1 ) * ( aDenominator < 0 ? -1 : 1 ) *
( aValue < 0 ? -1 : 1 );
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int64_t a = std::abs( aNumerator );
int64_t b = std::abs( aValue );
int64_t c = std::abs( aDenominator );
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r = c / 2;
if( b <= INT_MAX && c <= INT_MAX )
{
if( a <= INT_MAX )
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return sign * ( ( a * b + r ) / c );
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else
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return sign * ( a / c * b + ( a % c * b + r ) / c);
}
else
{
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uint64_t a0 = a & 0xFFFFFFFF;
uint64_t a1 = a >> 32;
uint64_t b0 = b & 0xFFFFFFFF;
uint64_t b1 = b >> 32;
uint64_t t1 = a0 * b1 + a1 * b0;
uint64_t t1a = t1 << 32;
int i;
a0 = a0 * b0 + t1a;
a1 = a1 * b1 + ( t1 >> 32 ) + ( a0 < t1a );
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a0 += r;
a1 += a0 < (uint64_t)r;
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for( i = 63; i >= 0; i-- )
{
a1 += a1 + ( ( a0 >> i ) & 1 );
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t1 += t1;
if( (uint64_t) c <= a1 )
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{
a1 -= c;
t1++;
}
}
return t1 * sign;
}
}