99 lines
2.8 KiB
C++
99 lines
2.8 KiB
C++
/*
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* This program source code file is part of KICAD, a free EDA CAD application.
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*
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* Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
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* Copyright (C) CERN
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* @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, you may find one here:
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* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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* or you may search the http://www.gnu.org website for the version 2 license,
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* or you may write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#ifndef __MATH_UTIL_H
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#define __MATH_UTIL_H
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#include <cmath>
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#include <cstdlib>
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#include <stdint.h>
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/**
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* Function rescale()
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*
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* Scales a number (value) by rational (numerator/denominator). Numerator must be <= denominator.
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*/
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template<typename T> static T rescale( T numerator, T value, T denominator )
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{
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return numerator * value / denominator;
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}
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// explicit specializations for integer types, taking care of overflow.
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template<> int rescale( int numerator, int value, int denominator )
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{
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return (int) ( (int64_t) numerator * (int64_t) value / (int64_t) denominator );
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}
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template<> int64_t rescale( int64_t numerator, int64_t value, int64_t denominator )
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{
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uint64_t r = 0;
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int64_t sign = ( ( numerator < 0) ? -1 : 1 ) * ( denominator < 0 ? - 1: 1 ) * (value < 0 ? - 1 : 1);
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uint64_t a = abs( numerator );
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uint64_t b = abs( value );
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uint64_t c = abs( denominator );
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r = c / 2;
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if( b <= INT_MAX && c <= INT_MAX )
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{
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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);
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} else {
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uint64_t a0 = a & 0xFFFFFFFF;
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uint64_t a1 = a >> 32;
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uint64_t b0 = b & 0xFFFFFFFF;
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uint64_t b1 = b >> 32;
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uint64_t t1 = a0 * b1 + a1 * b0;
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uint64_t t1a = t1 << 32;
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int i;
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a0 = a0 * b0 + t1a;
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a1 = a1 * b1 + (t1 >> 32) + (a0 < t1a);
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a0 += r;
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a1 += a0 < r;
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for( i = 63; i >= 0; i-- )
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{
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a1 += a1 + ( (a0 >> i) & 1 );
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t1 += t1;
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if( c <= a1 )
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{
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a1 -= c;
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t1++;
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}
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}
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return t1 * sign;
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}
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};
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#endif // __MATH_UTIL_H
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