kicad/libs/kimath/include/math/util.h

156 lines
4.6 KiB
C
Raw Normal View History

/*
* 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
* Copyright (C) 2021 KiCad Developers, see AUTHORS.txt for contributors.
*
2013-04-11 08:04:38 +00:00
* @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
*
* The equals() method to compare two floating point values adapted from
* AlmostEqualRelativeAndAbs() on
* https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
* (C) Bruce Dawson subject to the Apache 2.0 license.
*
* 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 UTIL_H
#define UTIL_H
#include <config.h>
#include <cstdint>
#include <limits>
#include <typeinfo>
#include <type_traits>
/**
* Helper to avoid directly including wx/log.h for the templated functions in kimath
*/
void kimathLogDebug( const char* aFormatString, ... );
/**
* Limit @a value within the range @a lower <= @a value <= @a upper.
*
* It will work on temporary expressions, since they are evaluated only once, and it should
* work on most if not all numeric types, string types, or any type for which "operator < ()"
* is present. The arguments are accepted in this order so you can remember the expression as
* a memory aid:
* <p>
* result is: lower <= value <= upper
*</p>
*/
template <typename T> inline const T& Clamp( const T& lower, const T& value, const T& upper )
{
if( value < lower )
return lower;
else if( upper < value )
return upper;
return value;
}
// Suppress an annoying warning that the explicit rounding we do is not precise
#ifdef HAVE_WIMPLICIT_FLOAT_CONVERSION
2020-07-02 23:10:31 +00:00
_Pragma( "GCC diagnostic push" ) \
_Pragma( "GCC diagnostic ignored \"-Wimplicit-int-float-conversion\"" )
#endif
/**
* Round a floating point number to an integer using "round halfway cases away from zero".
*
* In Debug build an assert fires if will not fit into the return type.
*/
template <typename fp_type, typename ret_type = int>
constexpr ret_type KiROUND( fp_type v )
{
using max_ret = long long int;
fp_type ret = v < 0 ? v - 0.5 : v + 0.5;
if( std::numeric_limits<ret_type>::max() < ret ||
std::numeric_limits<ret_type>::lowest() > ret )
{
kimathLogDebug( "Overflow KiROUND converting value %f to %s", double( v ),
typeid( ret_type ).name() );
return 0;
}
return ret_type( max_ret( ret ) );
}
#ifdef HAVE_WIMPLICIT_FLOAT_CONVERSION
2020-07-02 23:10:31 +00:00
_Pragma( "GCC diagnostic pop" )
#endif
/**
* Scale a number (value) by rational (numerator/denominator). Numerator must be <= denominator.
*/
template <typename T>
2013-10-14 18:40:36 +00:00
T rescale( T aNumerator, T aValue, T aDenominator )
{
return aNumerator * aValue / aDenominator;
}
template <typename T>
int sign( T val )
{
return ( T( 0 ) < val) - ( val < T( 0 ) );
}
// explicit specializations for integer types, taking care of overflow.
template <>
int rescale( int aNumerator, int aValue, int aDenominator );
template <>
int64_t rescale( int64_t aNumerator, int64_t aValue, int64_t aDenominator );
/**
* Template to compare two floating point values for equality within a required epsilon.
*
* @param aFirst value to compare.
* @param aSecond value to compare.
* @param aEpsilon allowed error.
* @return true if the values considered equal within the specified epsilon, otherwise false.
*/
template <class T>
typename std::enable_if<!std::numeric_limits<T>::is_integer, bool>::type
equals( T aFirst, T aSecond, T aEpsilon = std::numeric_limits<T>::epsilon() )
{
T diff = fabs( aFirst - aSecond );
if( diff < aEpsilon )
{
return true;
}
aFirst = fabs( aFirst );
aSecond = fabs( aSecond );
T largest = aFirst > aSecond ? aFirst : aSecond;
if( diff <= largest * aEpsilon )
{
return true;
}
return false;
}
#endif // UTIL_H