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// Copyright Catch2 Authors
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE.txt or copy at
// https://www.boost.org/LICENSE_1_0.txt)
// SPDX-License-Identifier: BSL-1.0
#ifndef CATCH_APPROX_HPP_INCLUDED
#define CATCH_APPROX_HPP_INCLUDED
#include <catch2/catch_tostring.hpp>
#include <type_traits>
#include <limits>
namespace Catch {
class Approx {
private:
// Performs equivalent check of std::fabs(lhs - rhs) <= margin
// But without the subtraction to allow for INFINITY in comparison
constexpr bool marginComparison (double lhs, double rhs, double margin) const {
return (lhs + margin >= rhs) && (rhs + margin >= lhs);
}
constexpr double fabs(double value) const {
return (value < 0.0) ? -value : value;
}
constexpr bool isinf(double value) const {
return value == std::numeric_limits<double>::infinity() || value == -std::numeric_limits<double>::infinity();
}
constexpr bool equalityComparisonImpl(double other) const {
// First try with fixed margin, then compute margin based on epsilon, scale and Approx's value
// Thanks to Richard Harris for his help refining the scaled margin value
return marginComparison(m_value, other, m_margin)
|| marginComparison(m_value, other, m_epsilon * (m_scale + fabs(isinf(m_value)? 0 : m_value)));
}
// Sets and validates the new epsilon (0 < epsilon < 1)
constexpr void setEpsilon(double epsilon) {
if(epsilon < 0)
throw std::domain_error("Invalid Approx::epsilon. Approx::epsilon has to be in [0, 1]");
m_epsilon = epsilon;
}
// Sets and validates the new margin (margin >= 0)
constexpr void setMargin(double margin) {
if(margin < 0)
throw std::domain_error("Invalid Approx::margin. Approx::Margin has to be non-negative.");
m_margin = margin;
}
public:
constexpr inline explicit Approx ( double value )
: m_epsilon( static_cast<double>(std::numeric_limits<float>::epsilon())*100. ),
m_margin( 0.0 ),
m_scale( 0.0 ),
m_value( value )
{}
static constexpr Approx custom() {
return Approx( 0.0 );
}
constexpr Approx operator-() const {
auto temp(*this);
temp.m_value = -temp.m_value;
return temp;
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
constexpr Approx operator()( T const& value ) const {
Approx approx( static_cast<double>(value) );
approx.m_epsilon = m_epsilon;
approx.m_margin = m_margin;
approx.m_scale = m_scale;
return approx;
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
constexpr inline explicit Approx( T const& value ): Approx(static_cast<double>(value))
{}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
friend constexpr bool operator == ( const T& lhs, Approx const& rhs ) {
auto lhs_v = static_cast<double>(lhs);
return rhs.equalityComparisonImpl(lhs_v);
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
friend constexpr bool operator == ( Approx const& lhs, const T& rhs ) {
return operator==( rhs, lhs );
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
friend constexpr bool operator != ( T const& lhs, Approx const& rhs ) {
return !operator==( lhs, rhs );
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
friend constexpr bool operator != ( Approx const& lhs, T const& rhs ) {
return !operator==( rhs, lhs );
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
friend constexpr bool operator <= ( T const& lhs, Approx const& rhs ) {
return static_cast<double>(lhs) < rhs.m_value || lhs == rhs;
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
friend constexpr bool operator <= ( Approx const& lhs, T const& rhs ) {
return lhs.m_value < static_cast<double>(rhs) || lhs == rhs;
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
friend constexpr bool operator >= ( T const& lhs, Approx const& rhs ) {
return static_cast<double>(lhs) > rhs.m_value || lhs == rhs;
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
friend constexpr bool operator >= ( Approx const& lhs, T const& rhs ) {
return lhs.m_value > static_cast<double>(rhs) || lhs == rhs;
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
constexpr Approx& epsilon( T const& newEpsilon ) {
const auto epsilonAsDouble = static_cast<double>(newEpsilon);
setEpsilon(epsilonAsDouble);
return *this;
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
constexpr Approx& margin( T const& newMargin ) {
const auto marginAsDouble = static_cast<double>(newMargin);
setMargin(marginAsDouble);
return *this;
}
template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
constexpr Approx& scale( T const& newScale ) {
m_scale = static_cast<double>(newScale);
return *this;
}
std::string toString() const;
private:
double m_epsilon;
double m_margin;
double m_scale;
double m_value;
};
namespace literals {
constexpr Approx operator ""_a(long double val) {
return Approx(val);
}
constexpr Approx operator ""_a(unsigned long long val) {
return Approx(val);
}
} // end namespace literals
template<>
struct StringMaker<Catch::Approx> {
static std::string convert(Catch::Approx const& value);
};
} // end namespace Catch
#endif // CATCH_APPROX_HPP_INCLUDED
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