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/*
* Created by Phil on 28/04/2011.
* Copyright 2010 Two Blue Cubes Ltd. All rights reserved.
*
* Distributed under the Boost Software License, Version 1.0. (See accompanying
* file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
*/
#ifndef TWOBLUECUBES_CATCH_APPROX_HPP_INCLUDED
#define TWOBLUECUBES_CATCH_APPROX_HPP_INCLUDED
#include "catch_tostring.h"
#include <cmath>
#include <limits>
#include <type_traits>
namespace Catch {
namespace Detail {
class Approx {
public:
explicit Approx ( double value )
: m_epsilon( std::numeric_limits<float>::epsilon()*100 ),
m_margin( 0.0 ),
m_scale( 1.0 ),
m_value( value )
{}
Approx( Approx const& other )
: m_epsilon( other.m_epsilon ),
m_margin( other.m_margin ),
m_scale( other.m_scale ),
m_value( other.m_value )
{}
static Approx custom() {
return Approx( 0 );
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
Approx operator()( T value ) {
Approx approx( static_cast<double>(value) );
approx.epsilon( m_epsilon );
approx.margin( m_margin );
approx.scale( m_scale );
return approx;
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
explicit Approx( T value ): Approx(static_cast<double>(value))
{}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator == ( const T& lhs, Approx const& rhs ) {
// Thanks to Richard Harris for his help refining this formula
auto lhs_v = double(lhs);
bool relativeOK = std::fabs(lhs_v - rhs.m_value) < rhs.m_epsilon * (rhs.m_scale + (std::max)(std::fabs(lhs_v), std::fabs(rhs.m_value)));
if (relativeOK) {
return true;
}
return std::fabs(lhs_v - rhs.m_value) < rhs.m_margin;
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator == ( Approx const& lhs, const T& rhs ) {
return operator==( rhs, lhs );
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator != ( T lhs, Approx const& rhs ) {
return !operator==( lhs, rhs );
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator != ( Approx const& lhs, T rhs ) {
return !operator==( rhs, lhs );
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator <= ( T lhs, Approx const& rhs ) {
return double(lhs) < rhs.m_value || lhs == rhs;
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator <= ( Approx const& lhs, T rhs ) {
return lhs.m_value < double(rhs) || lhs == rhs;
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator >= ( T lhs, Approx const& rhs ) {
return double(lhs) > rhs.m_value || lhs == rhs;
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator >= ( Approx const& lhs, T rhs ) {
return lhs.m_value > double(rhs) || lhs == rhs;
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
Approx& epsilon( T newEpsilon ) {
m_epsilon = double(newEpsilon);
return *this;
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
Approx& margin( T newMargin ) {
m_margin = double(newMargin);
return *this;
}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
Approx& scale( T newScale ) {
m_scale = double(newScale);
return *this;
}
std::string toString() const {
std::ostringstream oss;
oss << "Approx( " << Catch::toString( m_value ) << " )";
return oss.str();
}
private:
double m_epsilon;
double m_margin;
double m_scale;
double m_value;
};
}
template<>
inline std::string toString<Detail::Approx>( Detail::Approx const& value ) {
return value.toString();
}
} // end namespace Catch
#endif // TWOBLUECUBES_CATCH_APPROX_HPP_INCLUDED