190 lines
4.0 KiB
C++
190 lines
4.0 KiB
C++
#ifndef BOOST_REF_HPP_INCLUDED
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#define BOOST_REF_HPP_INCLUDED
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// MS compatible compilers support #pragma once
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#if defined(_MSC_VER) && (_MSC_VER >= 1020)
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# pragma once
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#endif
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#include <boost/config.hpp>
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#include <boost/utility/addressof.hpp>
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#include <boost/mpl/bool.hpp>
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#include <boost/detail/workaround.hpp>
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//
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// ref.hpp - ref/cref, useful helper functions
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//
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// Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
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// Copyright (C) 2001, 2002 Peter Dimov
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// Copyright (C) 2002 David Abrahams
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/bind/ref.html for documentation.
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//
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namespace boost
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{
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template<class T> class reference_wrapper
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{
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public:
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typedef T type;
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#if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, < 1300 )
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explicit reference_wrapper(T& t): t_(&t) {}
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#else
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explicit reference_wrapper(T& t): t_(boost::addressof(t)) {}
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#endif
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operator T& () const { return *t_; }
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T& get() const { return *t_; }
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T* get_pointer() const { return t_; }
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private:
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T* t_;
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};
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# if defined( __BORLANDC__ ) && BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581) )
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# define BOOST_REF_CONST
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# else
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# define BOOST_REF_CONST const
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# endif
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template<class T> inline reference_wrapper<T> BOOST_REF_CONST ref(T & t)
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{
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return reference_wrapper<T>(t);
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}
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template<class T> inline reference_wrapper<T const> BOOST_REF_CONST cref(T const & t)
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{
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return reference_wrapper<T const>(t);
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}
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# undef BOOST_REF_CONST
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# ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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template<typename T>
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class is_reference_wrapper
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: public mpl::false_
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{
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};
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template<typename T>
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class unwrap_reference
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{
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public:
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typedef T type;
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};
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# define AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(X) \
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template<typename T> \
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class is_reference_wrapper< X > \
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: public mpl::true_ \
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{ \
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}; \
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\
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template<typename T> \
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class unwrap_reference< X > \
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{ \
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public: \
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typedef T type; \
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}; \
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/**/
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AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(reference_wrapper<T>)
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#if !defined(BOOST_NO_CV_SPECIALIZATIONS)
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AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(reference_wrapper<T> const)
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AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(reference_wrapper<T> volatile)
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AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF(reference_wrapper<T> const volatile)
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#endif
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# undef AUX_REFERENCE_WRAPPER_METAFUNCTIONS_DEF
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# else // no partial specialization
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} // namespace boost
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#include <boost/type.hpp>
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namespace boost
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{
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namespace detail
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{
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typedef char (&yes_reference_wrapper_t)[1];
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typedef char (&no_reference_wrapper_t)[2];
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no_reference_wrapper_t is_reference_wrapper_test(...);
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template<typename T>
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yes_reference_wrapper_t is_reference_wrapper_test(type< reference_wrapper<T> >);
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template<bool wrapped>
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struct reference_unwrapper
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{
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template <class T>
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struct apply
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{
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typedef T type;
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};
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};
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template<>
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struct reference_unwrapper<true>
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{
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template <class T>
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struct apply
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{
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typedef typename T::type type;
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};
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};
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}
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template<typename T>
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class is_reference_wrapper
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{
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public:
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BOOST_STATIC_CONSTANT(
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bool, value = (
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sizeof(detail::is_reference_wrapper_test(type<T>()))
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== sizeof(detail::yes_reference_wrapper_t)));
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typedef ::boost::mpl::bool_<value> type;
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};
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template <typename T>
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class unwrap_reference
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: public detail::reference_unwrapper<
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is_reference_wrapper<T>::value
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>::template apply<T>
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{};
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# endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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template <class T> inline typename unwrap_reference<T>::type&
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unwrap_ref(T& t)
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{
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return t;
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}
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template<class T> inline T* get_pointer( reference_wrapper<T> const & r )
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{
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return r.get_pointer();
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}
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} // namespace boost
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#endif // #ifndef BOOST_REF_HPP_INCLUDED
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