

//  (C) Copyright Dave Abrahams, Steve Cleary, Beman Dawes, 

//      Howard Hinnant and John Maddock 2000. 

//  (C) Copyright Mat Marcus, Jesse Jones and Adobe Systems Inc 2001



//  Use, modification and distribution are subject to 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).

//

//  See http://www.boost.org/libs/type_traits for most recent version including documentation.



//    Fixed is_pointer, is_reference, is_const, is_volatile, is_same, 

//    is_member_pointer based on the Simulated Partial Specialization work 

//    of Mat Marcus and Jesse Jones. See  http://opensource.adobe.com or 

//    http://groups.yahoo.com/group/boost/message/5441 

//    Some workarounds in here use ideas suggested from "Generic<Programming>: 

//    Mappings between Types and Values" 

//    by Andrei Alexandrescu (see http://www.cuj.com/experts/1810/alexandr.html).





#ifndef BOOST_TT_IS_REFERENCE_HPP_INCLUDED

#define BOOST_TT_IS_REFERENCE_HPP_INCLUDED



#include <boost/type_traits/config.hpp>



#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

#   include <boost/type_traits/detail/yes_no_type.hpp>

#   include <boost/type_traits/detail/wrap.hpp>

#endif



// should be the last #include

#include <boost/type_traits/detail/bool_trait_def.hpp>



namespace boost {



#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION



BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_reference,T,false)

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T&,true)



#if defined(__BORLANDC__) && !defined(__COMO__) && (__BORLANDC__ < 0x600)

// these are illegal specialisations; cv-qualifies applied to

// references have no effect according to [8.3.2p1],

// C++ Builder requires them though as it treats cv-qualified

// references as distinct types...

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T& const,true)

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T& volatile,true)

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T& const volatile,true)

#endif



#if defined(__GNUC__) && (__GNUC__ < 3)

// these allow us to work around illegally cv-qualified reference

// types.

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T const ,::boost::is_reference<T>::value)

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T volatile ,::boost::is_reference<T>::value)

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_reference,T const volatile ,::boost::is_reference<T>::value)

// However, the above specializations confuse gcc 2.96 unless we also

// supply these specializations for array types

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_2(typename T,unsigned long N,is_reference,T[N],false)

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_2(typename T,unsigned long N,is_reference,const T[N],false)

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_2(typename T,unsigned long N,is_reference,volatile T[N],false)

BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_2(typename T,unsigned long N,is_reference,const volatile T[N],false)

#endif



#else



#ifdef BOOST_MSVC

#   pragma warning(push)

#   pragma warning(disable: 4181 4097)

#endif



namespace detail {



using ::boost::type_traits::yes_type;

using ::boost::type_traits::no_type;

using ::boost::type_traits::wrap;



template <class T> T&(* is_reference_helper1(wrap<T>) )(wrap<T>);

char is_reference_helper1(...);



template <class T> no_type is_reference_helper2(T&(*)(wrap<T>));

yes_type is_reference_helper2(...);



template <typename T>

struct is_reference_impl

{

    BOOST_STATIC_CONSTANT(

        bool, value = sizeof(

            ::boost::detail::is_reference_helper2(

                ::boost::detail::is_reference_helper1(::boost::type_traits::wrap<T>()))) == 1

        );

};



BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_reference,void,false)

#ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS

BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_reference,void const,false)

BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_reference,void volatile,false)

BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_reference,void const volatile,false)

#endif



} // namespace detail



BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_reference,T,::boost::detail::is_reference_impl<T>::value)



#ifdef BOOST_MSVC

#   pragma warning(pop)

#endif



#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION



} // namespace boost



#include <boost/type_traits/detail/bool_trait_undef.hpp>



#endif // BOOST_TT_IS_REFERENCE_HPP_INCLUDED



