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//
// Boost.Pointer Container
//
// Copyright Thorsten Ottosen 2003-2005. Use, modification and
// distribution is 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)
//
// For more information, see http://www.boost.org/libs/ptr_container/
//
#ifndef BOOST_INDIRECT_CONTAINER_NULLABLE_HPP
#define BOOST_INDIRECT_CONTAINER_NULLABLE_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif
#include <boost/type_traits/detail/yes_no_type.hpp>
#include <boost/mpl/eval_if.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/config.hpp>
namespace boost
{
template< class T >
struct nullable
{
typedef T type;
};
namespace ptr_container_detail
{
template< class T >
type_traits::yes_type is_nullable( const nullable<T>* );
type_traits::no_type is_nullable( ... );
}
template< class T >
struct is_nullable
{
private:
BOOST_STATIC_CONSTANT( T*, var );
public:
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(push)
#pragma warning(disable:6334)
#endif
BOOST_STATIC_CONSTANT(bool, value = sizeof( ptr_container_detail::is_nullable( var ) )
== sizeof( type_traits::yes_type ) );
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(pop)
#endif
};
template< class T >
struct remove_nullable
{
typedef BOOST_DEDUCED_TYPENAME mpl::eval_if< is_nullable<T>,
T,
mpl::identity<T> >::type
type;
};
}
#endif
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