williamr@2: #ifndef BOOST_REF_HPP_INCLUDED
williamr@2: #define BOOST_REF_HPP_INCLUDED
williamr@2: 
williamr@2: // MS compatible compilers support #pragma once
williamr@2: 
williamr@2: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
williamr@2: # pragma once
williamr@2: #endif
williamr@2: 
williamr@2: #include <boost/config.hpp>
williamr@2: #include <boost/utility/addressof.hpp>
williamr@2: #include <boost/mpl/bool.hpp>
williamr@2: #include <boost/detail/workaround.hpp>
williamr@2: 
williamr@2: //
williamr@2: //  ref.hpp - ref/cref, useful helper functions
williamr@2: //
williamr@2: //  Copyright (C) 1999, 2000 Jaakko Järvi (jaakko.jarvi@cs.utu.fi)
williamr@2: //  Copyright (C) 2001, 2002 Peter Dimov
williamr@2: //  Copyright (C) 2002 David Abrahams
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: //  See http://www.boost.org/libs/bind/ref.html for documentation.
williamr@2: //
williamr@2: 
williamr@2: namespace boost
williamr@2: {
williamr@2: 
williamr@2: template<class T> class reference_wrapper
williamr@2: { 
williamr@2: public:
williamr@2:     typedef T type;
williamr@2: 
williamr@2: #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, < 1300 )
williamr@2: 
williamr@2:     explicit reference_wrapper(T& t): t_(&t) {}
williamr@2: 
williamr@2: #else
williamr@2: 
williamr@2:     explicit reference_wrapper(T& t): t_(boost::addressof(t)) {}
williamr@2: 
williamr@2: #endif
williamr@2: 
williamr@2:     operator T& () const { return *t_; }
williamr@2: 
williamr@2:     T& get() const { return *t_; }
williamr@2: 
williamr@2:     T* get_pointer() const { return t_; }
williamr@2: 
williamr@2: private:
williamr@2: 
williamr@2:     T* t_;
williamr@2: };
williamr@2: 
williamr@2: # if defined( __BORLANDC__ ) && BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581) )
williamr@2: #  define BOOST_REF_CONST
williamr@2: # else
williamr@2: #  define BOOST_REF_CONST const
williamr@2: # endif
williamr@2: 
williamr@2: template<class T> inline reference_wrapper<T> BOOST_REF_CONST ref(T & t)
williamr@2: { 
williamr@2:     return reference_wrapper<T>(t);
williamr@2: }
williamr@2: 
williamr@2: template<class T> inline reference_wrapper<T const> BOOST_REF_CONST cref(T const & t)
williamr@2: {
williamr@2:     return reference_wrapper<T const>(t);
williamr@2: }
williamr@2: 
williamr@2: # undef BOOST_REF_CONST
williamr@2: 
williamr@2: # ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2: 
williamr@2: template<typename T>
williamr@2: class is_reference_wrapper
williamr@2:     : public mpl::false_
williamr@2: {
williamr@2: };
williamr@2: 
williamr@2: template<typename T>
williamr@2: class unwrap_reference
williamr@2: {
williamr@2:  public:
williamr@2:     typedef T type;
williamr@2: };
williamr@2: 
williamr@2: #  define AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(X) \
williamr@2: template<typename T> \
williamr@2: class is_reference_wrapper< X > \
williamr@2:     : public mpl::true_ \
williamr@2: { \
williamr@2: }; \
williamr@2: \
williamr@2: template<typename T> \
williamr@2: class unwrap_reference< X > \
williamr@2: { \
williamr@2:  public: \
williamr@2:     typedef T type; \
williamr@2: }; \
williamr@2: /**/
williamr@2: 
williamr@2: AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(reference_wrapper<T>)
williamr@2: #if !defined(BOOST_NO_CV_SPECIALIZATIONS)
williamr@2: AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(reference_wrapper<T> const)
williamr@2: AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(reference_wrapper<T> volatile)
williamr@2: AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(reference_wrapper<T> const volatile)
williamr@2: #endif
williamr@2: 
williamr@2: #  undef AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF
williamr@2: 
williamr@2: # else // no partial specialization
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #include <boost/type.hpp>
williamr@2: 
williamr@2: namespace boost
williamr@2: {
williamr@2: 
williamr@2: namespace detail
williamr@2: {
williamr@2:   typedef char (&yes_reference_wrapper_t)[1];
williamr@2:   typedef char (&no_reference_wrapper_t)[2];
williamr@2:       
williamr@2:   no_reference_wrapper_t is_reference_wrapper_test(...);
williamr@2: 
williamr@2:   template<typename T>
williamr@2:   yes_reference_wrapper_t is_reference_wrapper_test(type< reference_wrapper<T> >);
williamr@2: 
williamr@2:   template<bool wrapped>
williamr@2:   struct reference_unwrapper
williamr@2:   {
williamr@2:       template <class T>
williamr@2:       struct apply
williamr@2:       {
williamr@2:           typedef T type;
williamr@2:       };
williamr@2:   };
williamr@2: 
williamr@2:   template<>
williamr@2:   struct reference_unwrapper<true>
williamr@2:   {
williamr@2:       template <class T>
williamr@2:       struct apply
williamr@2:       {
williamr@2:           typedef typename T::type type;
williamr@2:       };
williamr@2:   };
williamr@2: }
williamr@2: 
williamr@2: template<typename T>
williamr@2: class is_reference_wrapper
williamr@2: {
williamr@2:  public:
williamr@2:     BOOST_STATIC_CONSTANT(
williamr@2:         bool, value = (
williamr@2:              sizeof(detail::is_reference_wrapper_test(type<T>()))
williamr@2:             == sizeof(detail::yes_reference_wrapper_t)));
williamr@2:     
williamr@2:     typedef ::boost::mpl::bool_<value> type;
williamr@2: };
williamr@2: 
williamr@2: template <typename T>
williamr@2: class unwrap_reference
williamr@2:     : public detail::reference_unwrapper<
williamr@2:         is_reference_wrapper<T>::value
williamr@2:       >::template apply<T>
williamr@2: {};
williamr@2: 
williamr@2: # endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #endif // #ifndef BOOST_REF_HPP_INCLUDED