| |
| #ifndef BOOST_MPL_MAP_AUX_AT_IMPL_HPP_INCLUDED |
| #define BOOST_MPL_MAP_AUX_AT_IMPL_HPP_INCLUDED |
| |
| // Copyright Aleksey Gurtovoy 2003-2004 |
| // Copyright David Abrahams 2003-2004 |
| // |
| // Distributed under 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/mpl for documentation. |
| |
| // $Id: at_impl.hpp 49267 2008-10-11 06:19:02Z agurtovoy $ |
| // $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $ |
| // $Revision: 49267 $ |
| |
| #include <boost/mpl/at_fwd.hpp> |
| #include <boost/mpl/long.hpp> |
| #include <boost/mpl/map/aux_/tag.hpp> |
| #include <boost/mpl/aux_/order_impl.hpp> |
| #include <boost/mpl/aux_/overload_names.hpp> |
| #include <boost/mpl/aux_/type_wrapper.hpp> |
| #include <boost/mpl/aux_/ptr_to_ref.hpp> |
| #include <boost/mpl/aux_/static_cast.hpp> |
| #include <boost/mpl/aux_/config/typeof.hpp> |
| #include <boost/mpl/aux_/config/ctps.hpp> |
| |
| #if !defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES) |
| # include <boost/mpl/eval_if.hpp> |
| # include <boost/mpl/pair.hpp> |
| # include <boost/mpl/void.hpp> |
| # include <boost/mpl/aux_/config/static_constant.hpp> |
| #endif |
| |
| namespace boost { namespace mpl { |
| |
| #if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES) |
| |
| template< typename Map, typename Key > |
| struct m_at |
| { |
| typedef aux::type_wrapper<Key> key_; |
| typedef __typeof__( BOOST_MPL_AUX_OVERLOAD_CALL_VALUE_BY_KEY( |
| Map |
| , BOOST_MPL_AUX_STATIC_CAST(key_*, 0) |
| ) ) type; |
| }; |
| |
| template<> |
| struct at_impl< aux::map_tag > |
| { |
| template< typename Map, typename Key > struct apply |
| : aux::wrapped_type< typename m_at< |
| Map |
| , Key |
| >::type > |
| { |
| }; |
| }; |
| |
| // agurt 31/jan/04: two-step implementation for the sake of GCC 3.x |
| template< typename Map, long order > |
| struct item_by_order_impl |
| { |
| typedef __typeof__( BOOST_MPL_AUX_OVERLOAD_CALL_ITEM_BY_ORDER( |
| Map |
| , BOOST_MPL_AUX_STATIC_CAST(long_<order>*, 0) |
| ) ) type; |
| }; |
| |
| template< typename Map, long order > |
| struct item_by_order |
| : aux::wrapped_type< |
| typename item_by_order_impl<Map,order>::type |
| > |
| { |
| }; |
| |
| #else // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES |
| |
| # if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
| |
| template< typename Map, long n > struct m_at |
| { |
| typedef void_ type; |
| }; |
| |
| # else |
| |
| template< long n > struct m_at_impl |
| { |
| template< typename Map > struct result_ |
| { |
| typedef void_ type; |
| }; |
| }; |
| |
| template< typename Map, long n > struct m_at |
| { |
| typedef typename m_at_impl<n>::result_<Map>::type type; |
| }; |
| |
| # endif |
| |
| |
| template<> |
| struct at_impl< aux::map_tag > |
| { |
| template< typename Map, typename Key > struct apply |
| { |
| typedef typename m_at< Map, (x_order_impl<Map,Key>::value - 2) >::type item_; |
| typedef typename eval_if< |
| is_void_<item_> |
| , void_ |
| , second<item_> |
| >::type type; |
| }; |
| }; |
| |
| template< typename Map, long order > struct is_item_masked |
| { |
| BOOST_STATIC_CONSTANT(bool, value = |
| sizeof( BOOST_MPL_AUX_OVERLOAD_CALL_IS_MASKED( |
| Map |
| , BOOST_MPL_AUX_STATIC_CAST(long_<order>*, 0) |
| ) ) == sizeof(aux::yes_tag) |
| ); |
| }; |
| |
| template< typename Map, long order > struct item_by_order |
| { |
| typedef typename eval_if_c< |
| is_item_masked<Map,order>::value |
| , void_ |
| , m_at<Map,(order - 2)> |
| >::type type; |
| }; |
| |
| #endif |
| |
| }} |
| |
| #endif // BOOST_MPL_SET_AUX_AT_IMPL_HPP_INCLUDED |