kicad/libs/kimath/src/math/util.cpp

/*
 * 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
 * Copyright (C) 2022-2023 KiCad Developers, see AUTHORS.txt for contributors.
 * @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 <limits>
#include <math/util.h>
#include <wx/log.h>
#include <wx/string.h>

#ifdef _MSC_VER
#include <windows.h>
#include <intrin.h>
#endif

// Fix compatibility with wxWidgets version < 3.1.4
#ifndef wxASCII_STR
    #define wxASCII_STR(s) wxString::FromAscii(s)
#endif

void kimathLogDebug( const char* aFormatString, ... )
{
    if( wxLog::IsLevelEnabled( wxLOG_Debug, wxString::FromAscii( wxLOG_COMPONENT ) ) )
    {
        va_list argList;
        va_start( argList, aFormatString );

        wxVLogWarning( aFormatString, argList );

        va_end( argList );
    }
}


void kimathLogOverflow( double v, const char* aTypeName )
{
    wxString typeName( aTypeName );
    wxFAIL_MSG( wxString::Format( wxT( "\n\nOverflow converting value %f to %s." ), v, typeName ) );
}


template<>
int rescale( int aNumerator, int aValue, int aDenominator )
{
    int64_t numerator = (int64_t) aNumerator * (int64_t) aValue;

    // round to nearest
    if( ( numerator < 0 ) ^ ( aDenominator < 0 ) )
        return ( numerator - aDenominator / 2 ) / aDenominator;
    else
        return ( numerator + aDenominator / 2 ) / aDenominator;

}


template<>
int64_t rescale( int64_t aNumerator, int64_t aValue, int64_t aDenominator )
{
#if defined( _M_X64 ) && ( _MSC_VER >= 1920 )
    int64_t  productHi;
    uint64_t productLo = static_cast<uint64_t>( _mul128( aNumerator, aValue, &productHi ) );

    int64_t r = ( ( productHi < 0 ) ^ ( aDenominator < 0 ) ) ? -aDenominator / 2 : aDenominator / 2;

    uint64_t rLo = static_cast<uint64_t>( r );
    int64_t  rHi = r < 0 ? -1ll : 0ll;

    productLo += rLo;
    productHi += rHi + ( productLo < rLo );

    __try
    {
        int64_t remainder;
        int64_t result = _div128( productHi, productLo, aDenominator, &remainder );

        return result;
    }
    __except( ( GetExceptionCode() == EXCEPTION_INT_OVERFLOW ) ? EXCEPTION_EXECUTE_HANDLER
                                                               : EXCEPTION_CONTINUE_SEARCH )
    {
        kimathLogDebug( "Overflow in rescale (%lld * %lld + %lld) / %lld", aNumerator, aValue, r,
                        aDenominator );
    }

    return 0;

#elif defined( __SIZEOF_INT128__ )
    __int128_t numerator = (__int128_t) aNumerator * (__int128_t) aValue;

    if( ( numerator < 0 ) ^ ( aDenominator < 0 ) )
        return ( numerator - aDenominator / 2 ) / aDenominator;
    else
        return ( numerator + aDenominator / 2 ) / aDenominator;

#else
    int64_t r = 0;
    int64_t sign = ( ( aNumerator < 0 ) ? -1 : 1 ) * ( aDenominator < 0 ? -1 : 1 ) *
                                                     ( aValue < 0 ? -1 : 1 );

    int64_t a = std::abs( aNumerator );
    int64_t b = std::abs( aValue );
    int64_t c = std::abs( aDenominator );

    r = c / 2;

    if( b <= std::numeric_limits<int>::max() && c <= std::numeric_limits<int>::max() )
    {
        if( a <= std::numeric_limits<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 < (uint64_t)r;

        for( i = 63; i >= 0; i-- )
        {
            a1  += a1 + ( ( a0 >> i ) & 1 );
            t1  += t1;

            if( (uint64_t) c <= a1 )
            {
                a1 -= c;
                t1++;
            }
        }

        return t1 * sign;
    }
#endif
}