// | |
// 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 |