| |
| // (C) Copyright John Maddock 2015. |
| // Use, modification and distribution are subject to the Boost Software License, |
| // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt). |
| // |
| // See http://www.boost.org/libs/type_traits for most recent version including documentation. |
| |
| #ifndef BOOST_TT_IS_CONSTRUCTIBLE_HPP_INCLUDED |
| #define BOOST_TT_IS_CONSTRUCTIBLE_HPP_INCLUDED |
| |
| #include <boost/type_traits/integral_constant.hpp> |
| #include <boost/detail/workaround.hpp> |
| |
| #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, < 1800) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40500) |
| |
| #include <boost/type_traits/is_destructible.hpp> |
| #include <boost/type_traits/is_default_constructible.hpp> |
| #include <boost/type_traits/detail/yes_no_type.hpp> |
| #include <boost/type_traits/declval.hpp> |
| |
| namespace boost{ |
| |
| namespace detail{ |
| |
| struct is_constructible_imp |
| { |
| template<typename T, typename ...TheArgs, typename = decltype(T(boost::declval<TheArgs>()...))> |
| static boost::type_traits::yes_type test(int); |
| template<typename, typename...> |
| static boost::type_traits::no_type test(...); |
| |
| template<typename T, typename Arg, typename = decltype(::new T(boost::declval<Arg>()))> |
| static boost::type_traits::yes_type test1(int); |
| template<typename, typename> |
| static boost::type_traits::no_type test1(...); |
| |
| template <typename T> |
| static boost::type_traits::yes_type ref_test(T); |
| template <typename T> |
| static boost::type_traits::no_type ref_test(...); |
| }; |
| |
| } |
| |
| template <class T, class ...Args> struct is_constructible : public integral_constant<bool, sizeof(detail::is_constructible_imp::test<T, Args...>(0)) == sizeof(boost::type_traits::yes_type)>{}; |
| template <class T, class Arg> struct is_constructible<T, Arg> : public integral_constant<bool, is_destructible<T>::value && sizeof(detail::is_constructible_imp::test1<T, Arg>(0)) == sizeof(boost::type_traits::yes_type)>{}; |
| template <class Ref, class Arg> struct is_constructible<Ref&, Arg> : public integral_constant<bool, sizeof(detail::is_constructible_imp::ref_test<Ref&>(boost::declval<Arg>())) == sizeof(boost::type_traits::yes_type)>{}; |
| template <class Ref, class Arg> struct is_constructible<Ref&&, Arg> : public integral_constant<bool, sizeof(detail::is_constructible_imp::ref_test<Ref&&>(boost::declval<Arg>())) == sizeof(boost::type_traits::yes_type)>{}; |
| |
| template <> struct is_constructible<void> : public false_type{}; |
| template <> struct is_constructible<void const> : public false_type{}; |
| template <> struct is_constructible<void const volatile> : public false_type{}; |
| template <> struct is_constructible<void volatile> : public false_type{}; |
| |
| template <class T> struct is_constructible<T> : public is_default_constructible<T>{}; |
| |
| #else |
| |
| #include <boost/type_traits/is_convertible.hpp> |
| #include <boost/type_traits/is_default_constructible.hpp> |
| |
| namespace boost{ |
| |
| // We don't know how to implement this: |
| template <class T, class U = void> struct is_constructible : public is_convertible<U, T>{}; |
| template <class T> struct is_constructible<T, void> : public is_default_constructible<T>{}; |
| template <> struct is_constructible<void, void> : public false_type{}; |
| template <> struct is_constructible<void const, void> : public false_type{}; |
| template <> struct is_constructible<void const volatile, void> : public false_type{}; |
| template <> struct is_constructible<void volatile, void> : public false_type{}; |
| template <class Ref> struct is_constructible<Ref&, void> : public false_type{}; |
| #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES |
| template <class Ref> struct is_constructible<Ref&&, void> : public false_type{}; |
| #endif |
| #endif |
| |
| } // namespace boost |
| |
| #endif // BOOST_TT_IS_CONSTRUCTIBLE_HPP_INCLUDED |