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Editing: constructible.hpp
// Boost.TypeErasure library // // Copyright 2011 Steven Watanabe // // Distributed under 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) // // $Id$ #if !defined(BOOST_PP_IS_ITERATING) #ifndef BOOST_TYPE_ERASURE_CONSTRUCTIBLE_HPP_INCLUDED #define BOOST_TYPE_ERASURE_CONSTRUCTIBLE_HPP_INCLUDED #include <boost/detail/workaround.hpp> #include <boost/preprocessor/iteration/iterate.hpp> #include <boost/preprocessor/repetition/enum_params.hpp> #include <boost/preprocessor/repetition/enum_binary_params.hpp> #include <boost/preprocessor/repetition/enum_trailing_params.hpp> #include <boost/type_erasure/detail/storage.hpp> #include <boost/type_erasure/call.hpp> #include <boost/type_erasure/concept_interface.hpp> #include <boost/type_erasure/config.hpp> #include <boost/type_erasure/param.hpp> namespace boost { namespace type_erasure { template<class Sig> struct constructible; namespace detail { template<class Sig> struct null_construct; template<class C> struct get_null_vtable_entry; template<class C, class Sig> struct vtable_adapter; } #ifdef BOOST_TYPE_ERASURE_DOXYGEN /** * The @ref constructible concept enables calling the * constructor of a type contained by an @ref any. * @c Sig should be a function signature. The return * type is the placeholder specifying the type to * be constructed. The arguments are the argument * types of the constructor. The arguments of * @c Sig may be placeholders. * * \note @ref constructible may not be specialized and * may not be passed to \call as it depends on the * implementation details of @ref any. */ template<class Sig> struct constructible {}; #elif !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && \ !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && \ !BOOST_WORKAROUND(BOOST_MSVC, == 1800) template<class R, class... T> struct constructible<R(T...)> { static ::boost::type_erasure::detail::storage apply(T... arg) { ::boost::type_erasure::detail::storage result; result.data = new R(::std::forward<T>(arg)...); return result; } }; /// INTERNAL ONLY template<class Base, class Tag, class... T> struct concept_interface< ::boost::type_erasure::constructible<Tag(T...)>, Base, Tag > : Base { using Base::_boost_type_erasure_deduce_constructor; ::boost::type_erasure::constructible<Tag(T...)>* _boost_type_erasure_deduce_constructor( typename ::boost::type_erasure::as_param<Base, T>::type...) const { return 0; } }; namespace detail { template<class... T> struct null_construct<void(T...)> { static ::boost::type_erasure::detail::storage value(T...) { ::boost::type_erasure::detail::storage result; result.data = 0; return result; } }; template<class T, class R, class... U> struct get_null_vtable_entry<vtable_adapter<constructible<T(const T&)>, R(U...)> > { typedef null_construct<void(U...)> type; }; } #else #define BOOST_PP_FILENAME_1 <boost/type_erasure/constructible.hpp> #define BOOST_PP_ITERATION_LIMITS (0, BOOST_TYPE_ERASURE_MAX_ARITY) #include BOOST_PP_ITERATE() #endif } } #endif #else #define N BOOST_PP_ITERATION() #define BOOST_TYPE_ERASURE_ARG_DECL(z, n, data) \ typename ::boost::type_erasure::as_param< \ Base, \ BOOST_PP_CAT(T, n) \ >::type #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES #define BOOST_TYPE_ERASURE_FORWARD_I(z, n, data) ::std::forward<BOOST_PP_CAT(T, n)>(BOOST_PP_CAT(arg, n)) #define BOOST_TYPE_ERASURE_FORWARD(n) BOOST_PP_ENUM(n, BOOST_TYPE_ERASURE_FORWARD_I, ~) #else #define BOOST_TYPE_ERASURE_FORWARD(n) BOOST_PP_ENUM_PARAMS(n, arg) #endif template<class R BOOST_PP_ENUM_TRAILING_PARAMS(N, class T)> struct constructible<R(BOOST_PP_ENUM_PARAMS(N, T))> { static ::boost::type_erasure::detail::storage apply(BOOST_PP_ENUM_BINARY_PARAMS(N, T, arg)) { ::boost::type_erasure::detail::storage result; result.data = new R(BOOST_TYPE_ERASURE_FORWARD(N)); return result; } }; template<class Base BOOST_PP_ENUM_TRAILING_PARAMS(N, class T), class Tag> struct concept_interface< ::boost::type_erasure::constructible<Tag(BOOST_PP_ENUM_PARAMS(N, T))>, Base, Tag > : Base { using Base::_boost_type_erasure_deduce_constructor; ::boost::type_erasure::constructible<Tag(BOOST_PP_ENUM_PARAMS(N, T))>* _boost_type_erasure_deduce_constructor( BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_ARG_DECL, ~)) const { return 0; } }; namespace detail { template<BOOST_PP_ENUM_PARAMS(N, class T)> struct null_construct<void(BOOST_PP_ENUM_PARAMS(N, T))> { static ::boost::type_erasure::detail::storage value(BOOST_PP_ENUM_PARAMS(N, T)) { ::boost::type_erasure::detail::storage result; result.data = 0; return result; } }; template<class T, class R BOOST_PP_ENUM_TRAILING_PARAMS(N, class T)> struct get_null_vtable_entry<vtable_adapter<constructible<T(const T&)>, R(BOOST_PP_ENUM_PARAMS(N, T))> > { typedef null_construct<void(BOOST_PP_ENUM_PARAMS(N, T))> type; }; } #undef BOOST_TYPE_ERASURE_FORWARD #undef BOOST_TYPE_ERASURE_FORWARD_I #undef BOOST_TYPE_ERASURE_ARG_DECL #undef N #endif
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