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- #ifndef BOOST_HOF_GUARD_CONSTRUCT_H
- #define BOOST_HOF_GUARD_CONSTRUCT_H
- #include <boost/hof/detail/forward.hpp>
- #include <boost/hof/detail/move.hpp>
- #include <boost/hof/detail/delegate.hpp>
- #include <boost/hof/detail/join.hpp>
- #include <boost/hof/detail/remove_rvalue_reference.hpp>
- #include <boost/hof/decay.hpp>
- #include <initializer_list>
- namespace boost { namespace hof {
- namespace detail {
- template<class T, class=void>
- struct construct_f
- {
- typedef typename std::aligned_storage<sizeof(T)>::type storage;
- struct storage_holder
- {
- storage * s;
- storage_holder(storage* x) noexcept : s(x)
- {}
- T& data() noexcept
- {
- return *reinterpret_cast<T*>(s);
- }
- ~storage_holder() noexcept(noexcept(std::declval<T>().~T()))
- {
- this->data().~T();
- }
- };
- constexpr construct_f() noexcept
- {}
- template<class... Ts, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, Ts...)>
- T operator()(Ts&&... xs) const BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(T, Ts&&...)
- {
- storage buffer{};
- new(&buffer) T(BOOST_HOF_FORWARD(Ts)(xs)...);
- storage_holder h(&buffer);
- return boost::hof::move(h.data());
- }
- template<class X, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, std::initializer_list<X>&&)>
- T operator()(std::initializer_list<X>&& x) const BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(T, std::initializer_list<X>&&)
- {
- storage buffer{};
- new(&buffer) T(static_cast<std::initializer_list<X>&&>(x));
- storage_holder h(&buffer);
- return h.data();
- }
- template<class X, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, std::initializer_list<X>&)>
- T operator()(std::initializer_list<X>& x) const BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(T, std::initializer_list<X>&)
- {
- storage buffer{};
- new(&buffer) T(x);
- storage_holder h(&buffer);
- return h.data();
- }
- template<class X, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, const std::initializer_list<X>&)>
- T operator()(const std::initializer_list<X>& x) const BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(T, const std::initializer_list<X>&)
- {
- storage buffer{};
- new(&buffer) T(x);
- storage_holder h(&buffer);
- return h.data();
- }
- };
- template<class T>
- struct construct_f<T, typename std::enable_if<BOOST_HOF_IS_LITERAL(T)>::type>
- {
- constexpr construct_f() noexcept
- {}
- template<class... Ts, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, Ts...)>
- constexpr T operator()(Ts&&... xs) const noexcept
- {
- return T(BOOST_HOF_FORWARD(Ts)(xs)...);
- }
- template<class X, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, std::initializer_list<X>&&)>
- constexpr T operator()(std::initializer_list<X>&& x) const noexcept
- {
- return T(static_cast<std::initializer_list<X>&&>(x));
- }
- template<class X, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, std::initializer_list<X>&)>
- constexpr T operator()(std::initializer_list<X>& x) const noexcept
- {
- return T(x);
- }
- template<class X, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, const std::initializer_list<X>&)>
- constexpr T operator()(const std::initializer_list<X>& x) const noexcept
- {
- return T(x);
- }
- };
- template<template<class...> class Template, template<class...> class D>
- struct construct_template_f
- {
- constexpr construct_template_f() noexcept
- {}
- template<class... Ts, class Result=BOOST_HOF_JOIN(Template, typename D<Ts>::type...),
- BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(Result, Ts...)>
- constexpr Result operator()(Ts&&... xs) const BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(Result, Ts&&...)
- {
- return construct_f<Result>()(BOOST_HOF_FORWARD(Ts)(xs)...);
- }
- };
- template<class MetafunctionClass>
- struct construct_meta_f
- {
- constexpr construct_meta_f() noexcept
- {}
- template<class... Ts>
- struct apply
- : MetafunctionClass::template apply<Ts...>
- {};
- template<class... Ts,
- class Metafunction=BOOST_HOF_JOIN(apply, Ts...),
- class Result=typename Metafunction::type,
- BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(Result, Ts...)>
- constexpr Result operator()(Ts&&... xs) const BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(Result, Ts&&...)
- {
- return construct_f<Result>()(BOOST_HOF_FORWARD(Ts)(xs)...);
- }
- };
- template<template<class...> class MetafunctionTemplate>
- struct construct_meta_template_f
- {
- constexpr construct_meta_template_f() noexcept
- {}
- template<class... Ts,
- class Metafunction=BOOST_HOF_JOIN(MetafunctionTemplate, Ts...),
- class Result=typename Metafunction::type,
- BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(Result, Ts...)>
- constexpr Result operator()(Ts&&... xs) const BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(Result, Ts&&...)
- {
- return construct_f<Result>()(BOOST_HOF_FORWARD(Ts)(xs)...);
- }
- };
- template<class T>
- struct construct_id
- {
- typedef T type;
- };
- }
- template<class T>
- constexpr detail::construct_f<T> construct() noexcept
- {
- return {};
- }
- template<class T>
- constexpr detail::construct_f<T> construct_forward() noexcept
- {
- return {};
- }
- template<class T>
- constexpr detail::construct_f<T> construct_basic() noexcept
- {
- return {};
- }
- template<template<class...> class Template>
- constexpr detail::construct_template_f<Template, detail::decay_mf> construct() noexcept
- {
- return {};
- }
- template<template<class...> class Template>
- constexpr detail::construct_template_f<Template, detail::construct_id> construct_forward() noexcept
- {
- return {};
- }
- template<template<class...> class Template>
- constexpr detail::construct_template_f<Template, detail::remove_rvalue_reference> construct_basic() noexcept
- {
- return {};
- }
- template<class T>
- constexpr detail::construct_meta_f<T> construct_meta() noexcept
- {
- return {};
- }
- template<template<class...> class Template>
- constexpr detail::construct_meta_template_f<Template> construct_meta() noexcept
- {
- return {};
- }
- }}
- #endif
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