williamr@2: //-----------------------------------------------------------------------------
williamr@2: // boost detail/reference_content.hpp header file
williamr@2: // See http://www.boost.org for updates, documentation, and revision history.
williamr@2: //-----------------------------------------------------------------------------
williamr@2: //
williamr@2: // Copyright (c) 2003
williamr@2: // Eric Friedman
williamr@2: //
williamr@2: // Distributed under the Boost Software License, Version 1.0. (See
williamr@2: // accompanying file LICENSE_1_0.txt or copy at
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: 
williamr@2: #ifndef BOOST_DETAIL_REFERENCE_CONTENT_HPP
williamr@2: #define BOOST_DETAIL_REFERENCE_CONTENT_HPP
williamr@2: 
williamr@2: #include "boost/config.hpp"
williamr@2: 
williamr@2: #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2: #   include "boost/mpl/bool.hpp"
williamr@2: #   include "boost/type_traits/has_nothrow_copy.hpp"
williamr@2: #else
williamr@2: #   include "boost/mpl/if.hpp"
williamr@2: #   include "boost/type_traits/is_reference.hpp"
williamr@2: #endif
williamr@2: 
williamr@2: #include "boost/mpl/void.hpp"
williamr@2: 
williamr@2: namespace boost {
williamr@2: 
williamr@2: namespace detail {
williamr@2: 
williamr@2: ///////////////////////////////////////////////////////////////////////////////
williamr@2: // (detail) class template reference_content
williamr@2: //
williamr@2: // Non-Assignable wrapper for references.
williamr@2: //
williamr@2: template <typename RefT>
williamr@2: class reference_content
williamr@2: {
williamr@2: private: // representation
williamr@2: 
williamr@2:     RefT content_;
williamr@2: 
williamr@2: public: // structors
williamr@2: 
williamr@2:     ~reference_content()
williamr@2:     {
williamr@2:     }
williamr@2: 
williamr@2:     reference_content(RefT r)
williamr@2:         : content_( r )
williamr@2:     {
williamr@2:     }
williamr@2: 
williamr@2:     reference_content(const reference_content& operand)
williamr@2:         : content_( operand.content_ )
williamr@2:     {
williamr@2:     }
williamr@2: 
williamr@2: private: // non-Assignable
williamr@2: 
williamr@2:     reference_content& operator=(const reference_content&);
williamr@2: 
williamr@2: public: // queries
williamr@2: 
williamr@2:     RefT get() const
williamr@2:     {
williamr@2:         return content_;
williamr@2:     }
williamr@2: 
williamr@2: };
williamr@2: 
williamr@2: ///////////////////////////////////////////////////////////////////////////////
williamr@2: // (detail) metafunction make_reference_content
williamr@2: //
williamr@2: // Wraps with reference_content if specified type is reference.
williamr@2: //
williamr@2: 
williamr@2: template <typename T = mpl::void_> struct make_reference_content;
williamr@2: 
williamr@2: #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2: 
williamr@2: template <typename T>
williamr@2: struct make_reference_content
williamr@2: {
williamr@2:     typedef T type;
williamr@2: };
williamr@2: 
williamr@2: template <typename T>
williamr@2: struct make_reference_content< T& >
williamr@2: {
williamr@2:     typedef reference_content<T&> type;
williamr@2: };
williamr@2: 
williamr@2: #else // defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2: 
williamr@2: template <typename T>
williamr@2: struct make_reference_content
williamr@2:     : mpl::if_<
williamr@2:           is_reference<T>
williamr@2:         , reference_content<T>
williamr@2:         , T
williamr@2:         >
williamr@2: {
williamr@2: };
williamr@2: 
williamr@2: #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION workaround
williamr@2: 
williamr@2: template <>
williamr@2: struct make_reference_content< mpl::void_ >
williamr@2: {
williamr@2:     template <typename T>
williamr@2:     struct apply
williamr@2:         : make_reference_content<T>
williamr@2:     {
williamr@2:     };
williamr@2: 
williamr@2:     typedef mpl::void_ type;
williamr@2: };
williamr@2: 
williamr@2: } // namespace detail
williamr@2: 
williamr@2: ///////////////////////////////////////////////////////////////////////////////
williamr@2: // reference_content<T&> type traits specializations
williamr@2: //
williamr@2: 
williamr@2: #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2: 
williamr@2: template <typename T>
williamr@2: struct has_nothrow_copy<
williamr@2:       ::boost::detail::reference_content< T& >
williamr@2:     >
williamr@2:     : mpl::true_
williamr@2: {
williamr@2: };
williamr@2: 
williamr@2: #endif // !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #endif // BOOST_DETAIL_REFERENCE_CONTENT_HPP