//----------------------------------------------------------------------------- // boost detail/reference_content.hpp header file // See http://www.boost.org for updates, documentation, and revision history. //----------------------------------------------------------------------------- // // Copyright (c) 2003 // Eric Friedman // // 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) #ifndef BOOST_DETAIL_REFERENCE_CONTENT_HPP #define BOOST_DETAIL_REFERENCE_CONTENT_HPP #include "boost/config.hpp" #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) # include "boost/mpl/bool.hpp" # include "boost/type_traits/has_nothrow_copy.hpp" #else # include "boost/mpl/if.hpp" # include "boost/type_traits/is_reference.hpp" #endif #include "boost/mpl/void.hpp" namespace boost { namespace detail { /////////////////////////////////////////////////////////////////////////////// // (detail) class template reference_content // // Non-Assignable wrapper for references. // template <typename RefT> class reference_content { private: // representation RefT content_; public: // structors ~reference_content() { } reference_content(RefT r) : content_( r ) { } reference_content(const reference_content& operand) : content_( operand.content_ ) { } private: // non-Assignable reference_content& operator=(const reference_content&); public: // queries RefT get() const { return content_; } }; /////////////////////////////////////////////////////////////////////////////// // (detail) metafunction make_reference_content // // Wraps with reference_content if specified type is reference. // template <typename T = mpl::void_> struct make_reference_content; #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) template <typename T> struct make_reference_content { typedef T type; }; template <typename T> struct make_reference_content< T& > { typedef reference_content<T&> type; }; #else // defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) template <typename T> struct make_reference_content : mpl::if_< is_reference<T> , reference_content<T> , T > { }; #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION workaround template <> struct make_reference_content< mpl::void_ > { template <typename T> struct apply : make_reference_content<T> { }; typedef mpl::void_ type; }; } // namespace detail /////////////////////////////////////////////////////////////////////////////// // reference_content<T&> type traits specializations // #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) template <typename T> struct has_nothrow_copy< ::boost::detail::reference_content< T& > > : mpl::true_ { }; #endif // !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) } // namespace boost #endif // BOOST_DETAIL_REFERENCE_CONTENT_HPP