Metaprogramming.h

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/*
 * Copyright (c) 2018-2019 pongasoft
 *
 * Licensed under the Apache License, Version 2.0 or the MIT license,
 * at your option. You may not use this file except in compliance with
 * one of these licenses. You may obtain copies of the licenses at:
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 * https://opensource.org/licenses/MIT
 *
 * 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
 
#include <type_traits>
#include <sstream>
#include <ostream>
#include "Cpp17.h"
 
namespace pongasoft::Utils {

template<typename U>
class Cast
{
public:
  template<typename T>
  static inline U dynamic(T *iPtr)
  {
    if constexpr (std::is_polymorphic<T>::value)
    {
      return dynamic_cast<U>(iPtr);
    }
    else
    {
      return nullptr;
    }
  }
};

template<typename T>
using operator_not_eq_t = decltype(std::declval<T const&>() != std::declval<T const&>());

template<typename T>
constexpr auto is_operator_not_eq_defined = cpp17::experimental::is_detected_v<operator_not_eq_t, T>;

template<typename From, typename To>
using static_cast_t = decltype(static_cast<To>(std::declval<From>()));

template<typename From, typename To>
constexpr auto is_static_cast_defined = cpp17::experimental::is_detected_v<static_cast_t, From, To>;

template<typename T>
using operator_write_to_ostream_t = decltype(std::declval<std::ostream &>() << std::declval<T const&>());

template<typename T>
constexpr auto is_operator_write_to_ostream_defined = cpp17::experimental::is_detected_v<operator_write_to_ostream_t, T>;

template<typename T>
std::string typeString()
{
  std::stringstream s;
  s << typeid(T).name();
  if(std::is_const_v<typename std::remove_reference<T>::type>)
    s << " const";
  if(std::is_reference_v<T>)
    s << " &";
  return s.str();
}
 
}