type_traits.hpp
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| text/x-c++hdr
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CppLexer
| r4 | #ifndef OPAQUE_TYPE_TRAITS_HPP | |||
| #define OPAQUE_TYPE_TRAITS_HPP | ||||
| // | ||||
| // Copyright (c) 2015 | ||||
| // Kyle Markley. All rights reserved. | ||||
| // | ||||
| // Redistribution and use in source and binary forms, with or without | ||||
| // modification, are permitted provided that the following conditions are met: | ||||
| // | ||||
| // 1. Redistributions of source code must retain the above copyright notice, | ||||
| // this list of conditions and the following disclaimer. | ||||
| // 2. Redistributions in binary form must reproduce the above copyright notice, | ||||
| // this list of conditions and the following disclaimer in the documentation | ||||
| // and/or other materials provided with the distribution. | ||||
| // 3. Neither the name of the author nor the names of any contributors may be | ||||
| // used to endorse or promote products derived from this software without | ||||
| // specific prior written permission. | ||||
| // | ||||
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | ||||
| // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||||
| // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | ||||
| // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE | ||||
| // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | ||||
| // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | ||||
| // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | ||||
| // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | ||||
| // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | ||||
| // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | ||||
| // POSSIBILITY OF SUCH DAMAGE. | ||||
| // | ||||
| #include <type_traits> | ||||
| namespace opaque { | ||||
| /// \addtogroup internal | ||||
| /// @{ | ||||
| #ifdef __cpp_lib_void_t | ||||
| using std::void_t; | ||||
| #else | ||||
| // CWG 1558 | ||||
| template <typename...> struct voider { using type = void; }; | ||||
| template <typename... T> using void_t = typename voider<T...>::type; | ||||
| #endif | ||||
| namespace detail { | ||||
| template <typename F, typename... Args> | ||||
| using functor_result_t = decltype(std::declval<F>()(std::declval<Args>()...)); | ||||
| template <typename F, typename = void, typename... Args> | ||||
| struct functor_well_formed : std::false_type { }; | ||||
| template <typename F, typename... Args> | ||||
| struct functor_well_formed<F, void_t<functor_result_t<F,Args...>>, Args...> | ||||
| : std::true_type { | ||||
| using result_type = functor_result_t<F,Args...>; | ||||
| }; | ||||
| } | ||||
| template <typename F, typename... Args> | ||||
| using is_functor_call_well_formed | ||||
| = detail::functor_well_formed<F, void, Args...>; | ||||
| /// | ||||
| /// Determine whether a type is decayed | ||||
| /// | ||||
| template <typename T> | ||||
| struct is_decayed : std::conditional< | ||||
| std::is_same<T, typename std::decay<T>::type>::value, | ||||
| std::true_type, std::false_type>::type { }; | ||||
| /// | ||||
| /// Determine whether two types are related by inheritance | ||||
| /// | ||||
| template <typename T, typename U> | ||||
| struct is_related : std::conditional< | ||||
| std::is_base_of<T,U>::value or std::is_base_of<U,T>::value, | ||||
| std::true_type, std::false_type>::type { }; | ||||
| /// | ||||
| /// Determine whether casting to T from U is free, or creates a new object | ||||
| /// | ||||
| template <typename T, typename U> | ||||
| struct is_cast_free : std::conditional< | ||||
| std::is_same<T,U>::value or is_related<T,U>::value, | ||||
| std::true_type, std::false_type>::type { }; | ||||
| /// @} | ||||
| } | ||||
| #endif | ||||
