williamr@2: // williamr@2: // Boost.Pointer Container williamr@2: // williamr@2: // Copyright Thorsten Ottosen 2003-2005. Use, modification and williamr@2: // distribution is subject to the Boost Software License, Version williamr@2: // 1.0. (See accompanying file LICENSE_1_0.txt or copy at williamr@2: // http://www.boost.org/LICENSE_1_0.txt) williamr@2: // williamr@2: // For more information, see http://www.boost.org/libs/ptr_container/ williamr@2: // williamr@2: williamr@2: williamr@2: #ifndef BOOST_INDIRECT_CONTAINER_NULLABLE_HPP williamr@2: #define BOOST_INDIRECT_CONTAINER_NULLABLE_HPP williamr@2: williamr@2: #if defined(_MSC_VER) && (_MSC_VER >= 1200) williamr@2: # pragma once williamr@2: #endif williamr@2: williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: #include williamr@2: williamr@2: namespace boost williamr@2: { williamr@2: williamr@2: template< class T > williamr@2: struct nullable williamr@2: { williamr@2: typedef T type; williamr@2: }; williamr@2: williamr@2: namespace ptr_container_detail williamr@2: { williamr@2: template< class T > williamr@2: type_traits::yes_type is_nullable( const nullable* ); williamr@2: williamr@2: type_traits::no_type is_nullable( ... ); williamr@2: } williamr@2: williamr@2: template< class T > williamr@2: struct is_nullable williamr@2: { williamr@2: private: williamr@2: BOOST_STATIC_CONSTANT( T*, var ); williamr@2: public: williamr@2: BOOST_STATIC_CONSTANT(bool, value = sizeof( ptr_container_detail::is_nullable( var ) ) williamr@2: == sizeof( type_traits::yes_type ) ); williamr@2: }; williamr@2: williamr@2: template< class T > williamr@2: struct remove_nullable williamr@2: { williamr@2: typedef BOOST_DEDUCED_TYPENAME mpl::eval_if< is_nullable, williamr@2: T, williamr@2: mpl::identity >::type williamr@2: type; williamr@2: }; williamr@2: williamr@2: } williamr@2: williamr@2: #endif