//-----------------------------------------------------------------------------

// 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