1  
  2  //              Copyright Catch2 Authors
  3  // Distributed under the Boost Software License, Version 1.0.
  4  //   (See accompanying file LICENSE.txt or copy at
  5  //        https://www.boost.org/LICENSE_1_0.txt)
  6  
  7  // SPDX-License-Identifier: BSL-1.0
  8  #ifndef CATCH_APPROX_HPP_INCLUDED
  9  #define CATCH_APPROX_HPP_INCLUDED
 10  
 11  #include <catch2/catch_tostring.hpp>
 12  
 13  #include <type_traits>
 14  
 15  namespace Catch {
 16  
 17      class Approx {
 18      private:
 19          bool equalityComparisonImpl(double other) const;
 20          // Sets and validates the new margin (margin >= 0)
 21          void setMargin(double margin);
 22          // Sets and validates the new epsilon (0 < epsilon < 1)
 23          void setEpsilon(double epsilon);
 24  
 25      public:
 26          explicit Approx ( double value );
 27  
 28          static Approx custom();
 29  
 30          Approx operator-() const;
 31  
 32          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 33          Approx operator()( T const& value ) const {
 34              Approx approx( static_cast<double>(value) );
 35              approx.m_epsilon = m_epsilon;
 36              approx.m_margin = m_margin;
 37              approx.m_scale = m_scale;
 38              return approx;
 39          }
 40  
 41          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 42          explicit Approx( T const& value ): Approx(static_cast<double>(value))
 43          {}
 44  
 45  
 46          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 47          friend bool operator == ( const T& lhs, Approx const& rhs ) {
 48              auto lhs_v = static_cast<double>(lhs);
 49              return rhs.equalityComparisonImpl(lhs_v);
 50          }
 51  
 52          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 53          friend bool operator == ( Approx const& lhs, const T& rhs ) {
 54              return operator==( rhs, lhs );
 55          }
 56  
 57          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 58          friend bool operator != ( T const& lhs, Approx const& rhs ) {
 59              return !operator==( lhs, rhs );
 60          }
 61  
 62          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 63          friend bool operator != ( Approx const& lhs, T const& rhs ) {
 64              return !operator==( rhs, lhs );
 65          }
 66  
 67          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 68          friend bool operator <= ( T const& lhs, Approx const& rhs ) {
 69              return static_cast<double>(lhs) < rhs.m_value || lhs == rhs;
 70          }
 71  
 72          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 73          friend bool operator <= ( Approx const& lhs, T const& rhs ) {
 74              return lhs.m_value < static_cast<double>(rhs) || lhs == rhs;
 75          }
 76  
 77          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 78          friend bool operator >= ( T const& lhs, Approx const& rhs ) {
 79              return static_cast<double>(lhs) > rhs.m_value || lhs == rhs;
 80          }
 81  
 82          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 83          friend bool operator >= ( Approx const& lhs, T const& rhs ) {
 84              return lhs.m_value > static_cast<double>(rhs) || lhs == rhs;
 85          }
 86  
 87          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 88          Approx& epsilon( T const& newEpsilon ) {
 89              const auto epsilonAsDouble = static_cast<double>(newEpsilon);
 90              setEpsilon(epsilonAsDouble);
 91              return *this;
 92          }
 93  
 94          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
 95          Approx& margin( T const& newMargin ) {
 96              const auto marginAsDouble = static_cast<double>(newMargin);
 97              setMargin(marginAsDouble);
 98              return *this;
 99          }
100  
101          template <typename T, typename = std::enable_if_t<std::is_constructible<double, T>::value>>
102          Approx& scale( T const& newScale ) {
103              m_scale = static_cast<double>(newScale);
104              return *this;
105          }
106  
107          std::string toString() const;
108  
109      private:
110          double m_epsilon;
111          double m_margin;
112          double m_scale;
113          double m_value;
114      };
115  
116  namespace literals {
117      Approx operator ""_a(long double val);
118      Approx operator ""_a(unsigned long long val);
119  } // end namespace literals
120  
121  template<>
122  struct StringMaker<Catch::Approx> {
123      static std::string convert(Catch::Approx const& value);
124  };
125  
126  } // end namespace Catch
127  
128  #endif // CATCH_APPROX_HPP_INCLUDED