detect.h

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/*
 *    Copyright 2023 The ChampSim Contributors
 *
 * 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.
 */
 
#ifndef UTIL_DETECT_H
#define UTIL_DETECT_H
 
/*
 * This is a port of <experimental/type_traits> detection idiom
 *
 * The port is used here so as not to depend on the presence of the experimental header
 */
 
#include <type_traits>
 
namespace champsim
{
namespace detail
{
template <class Default, class AlwaysVoid, template <class...> class Op, class... Args>
struct detector {
  using value_t = std::false_type;
  using type = Default;
};
 
template <class Default, template <class...> class Op, class... Args>
struct detector<Default, std::void_t<Op<Args...>>, Op, Args...> {
  using value_t = std::true_type;
  using type = Op<Args...>;
};
 
} // namespace detail
 
struct nonesuch {
  ~nonesuch() = delete;
  nonesuch(nonesuch const&) = delete;
  void operator=(nonesuch const&) = delete;
};
 
template <template <class...> class Op, class... Args>
using is_detected = typename detail::detector<nonesuch, void, Op, Args...>::value_t;
 
template <template <class...> class Op, class... Args>
using detected_t = typename detail::detector<nonesuch, void, Op, Args...>::type;
 
template <class Default, template <class...> class Op, class... Args>
using detected_or = detail::detector<Default, void, Op, Args...>;
 
template <template <class...> class Op, class... Args>
constexpr inline bool is_detected_v = is_detected<Op, Args...>::value;
 
template <class Default, template <class...> class Op, class... Args>
using detected_or_t = typename detected_or<Default, Op, Args...>::type;
 
template <class Expected, template <class...> class Op, class... Args>
using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;
 
template <class Expected, template <class...> class Op, class... Args>
constexpr inline bool is_detected_exact_v = is_detected_exact<Expected, Op, Args...>::value;
 
template <class To, template <class...> class Op, class... Args>
using is_detected_convertible = std::is_convertible<detected_t<Op, Args...>, To>;
 
template <class To, template <class...> class Op, class... Args>
constexpr inline bool is_detected_convertible_v = is_detected_convertible<To, Op, Args...>::value;
} // namespace champsim
#endif