Operators.h

Go to the documentation of this file.

/*
 * Copyright (c) 2020 pongasoft
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 *
 * @author Yan Pujante
 */

#pragma once

namespace pongasoft::Utils::Operators {

template<typename T>
class Dereferenceable
{
public:
  // LHS is reference, RHS is reference
  friend constexpr bool operator==(T const &lhs, T const &rhs) { return *lhs == *rhs; }

  friend constexpr bool operator!=(T const &lhs, T const &rhs) { return !(lhs == rhs); }

  friend constexpr bool operator<(T const &lhs, T const &rhs) { return *lhs < *rhs; }

  friend constexpr bool operator>(T const &lhs, T const &rhs) { return rhs < lhs; }

  friend constexpr bool operator<=(T const &lhs, T const &rhs) { return !(rhs < lhs); }

  friend constexpr bool operator>=(T const &lhs, T const &rhs) { return !(lhs < rhs); }

  // LHS is reference, RHS is value
  template<typename V>
  friend constexpr bool operator==(T const &lhs, V const &rhs) { return *lhs == rhs; }

  template<typename V>
  friend constexpr bool operator!=(T const &lhs, V const &rhs) { return !(lhs == rhs); }

  template<typename V>
  friend constexpr bool operator<(T const &lhs, V const &rhs) { return *lhs < rhs; }

  template<typename V>
  friend constexpr bool operator>(T const &lhs, V const &rhs) { return !(lhs < rhs) && lhs != rhs; }

  template<typename V>
  friend constexpr bool operator<=(T const &lhs, V const &rhs) { return !(rhs < lhs); }

  template<typename V>
  friend constexpr bool operator>=(T const &lhs, V const &rhs) { return !(lhs < rhs); }

  // LHS is value, RHS is reference
  template<typename V>
  friend constexpr bool operator==(V const &lhs, T const &rhs) { return rhs == lhs; }

  template<typename V>
  friend constexpr bool operator!=(V const &lhs, T const &rhs) { return !(lhs == rhs); }

  template<typename V>
  friend constexpr bool operator<(V const &lhs, T const &rhs) { return rhs > lhs; }

  template<typename V>
  friend constexpr bool operator>(V const &lhs, T const &rhs) { return rhs < lhs; }

  template<typename V>
  friend constexpr bool operator<=(V const &lhs, T const &rhs) { return !(rhs < lhs); }

  template<typename V>
  friend constexpr bool operator>=(V const &lhs, T const &rhs) { return !(lhs < rhs); }
};

}