kicad/include/math/math_util.h

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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>
2013-04-11 08:04:38 +00:00
* 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
*/
#ifndef __MATH_UTIL_H
#define __MATH_UTIL_H
#include <cmath>
#include <cstdlib>
#include <stdint.h>
/**
* Function rescale()
*
* Scales a number (value) by rational (numerator/denominator). Numerator must be <= denominator.
*/
template<typename T> static T rescale( T numerator, T value, T denominator )
{
return numerator * value / denominator;
}
// explicit specializations for integer types, taking care of overflow.
template<> int rescale( int numerator, int value, int denominator )
{
return (int) ( (int64_t) numerator * (int64_t) value / (int64_t) denominator );
}
template<> int64_t rescale( int64_t numerator, int64_t value, int64_t denominator )
{
uint64_t r = 0;
int64_t sign = ( ( numerator < 0) ? -1 : 1 ) * ( denominator < 0 ? - 1: 1 ) * (value < 0 ? - 1 : 1);
uint64_t a = abs( numerator );
uint64_t b = abs( value );
uint64_t c = abs( denominator );
r = c / 2;
if( b <= INT_MAX && c <= INT_MAX )
{
if( a <= INT_MAX )
return sign * ( (a * b + r ) / c );
else
return sign * (a / c * b + (a % c * b + r) / c);
} else {
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);
a0 += r;
a1 += a0 < r;
for( i = 63; i >= 0; i-- )
{
a1 += a1 + ( (a0 >> i) & 1 );
t1 += t1;
if( c <= a1 )
{
a1 -= c;
t1++;
}
}
return t1 * sign;
}
};
#endif // __MATH_UTIL_H