145 lines
3.6 KiB
C++
145 lines
3.6 KiB
C++
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#ifndef BOOST_MPL_MAP_AUX_AT_IMPL_HPP_INCLUDED
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#define BOOST_MPL_MAP_AUX_AT_IMPL_HPP_INCLUDED
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// Copyright Aleksey Gurtovoy 2003-2004
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// Copyright David Abrahams 2003-2004
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/mpl for documentation.
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// $Id: at_impl.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
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// $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $
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// $Revision: 49267 $
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#include <boost/mpl/at_fwd.hpp>
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#include <boost/mpl/long.hpp>
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#include <boost/mpl/map/aux_/tag.hpp>
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#include <boost/mpl/aux_/order_impl.hpp>
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#include <boost/mpl/aux_/overload_names.hpp>
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#include <boost/mpl/aux_/type_wrapper.hpp>
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#include <boost/mpl/aux_/ptr_to_ref.hpp>
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#include <boost/mpl/aux_/static_cast.hpp>
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#include <boost/mpl/aux_/config/typeof.hpp>
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#include <boost/mpl/aux_/config/ctps.hpp>
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#if !defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
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# include <boost/mpl/eval_if.hpp>
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# include <boost/mpl/pair.hpp>
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# include <boost/mpl/void.hpp>
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# include <boost/mpl/aux_/config/static_constant.hpp>
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#endif
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namespace boost { namespace mpl {
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#if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
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template< typename Map, typename Key >
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struct m_at
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{
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typedef aux::type_wrapper<Key> key_;
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typedef __typeof__( BOOST_MPL_AUX_OVERLOAD_CALL_VALUE_BY_KEY(
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Map
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, BOOST_MPL_AUX_STATIC_CAST(key_*, 0)
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) ) type;
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};
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template<>
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struct at_impl< aux::map_tag >
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{
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template< typename Map, typename Key > struct apply
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: aux::wrapped_type< typename m_at<
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Map
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, Key
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>::type >
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{
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};
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};
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// agurt 31/jan/04: two-step implementation for the sake of GCC 3.x
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template< typename Map, long order >
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struct item_by_order_impl
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{
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typedef __typeof__( BOOST_MPL_AUX_OVERLOAD_CALL_ITEM_BY_ORDER(
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Map
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, BOOST_MPL_AUX_STATIC_CAST(long_<order>*, 0)
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) ) type;
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};
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template< typename Map, long order >
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struct item_by_order
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: aux::wrapped_type<
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typename item_by_order_impl<Map,order>::type
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>
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{
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};
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#else // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES
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# if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
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template< typename Map, long n > struct m_at
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{
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typedef void_ type;
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};
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# else
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template< long n > struct m_at_impl
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{
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template< typename Map > struct result_
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{
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typedef void_ type;
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};
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};
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template< typename Map, long n > struct m_at
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{
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typedef typename m_at_impl<n>::result_<Map>::type type;
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};
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# endif
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template<>
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struct at_impl< aux::map_tag >
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{
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template< typename Map, typename Key > struct apply
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{
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typedef typename m_at< Map, (x_order_impl<Map,Key>::value - 2) >::type item_;
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typedef typename eval_if<
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is_void_<item_>
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, void_
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, second<item_>
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>::type type;
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};
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};
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template< typename Map, long order > struct is_item_masked
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{
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BOOST_STATIC_CONSTANT(bool, value =
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sizeof( BOOST_MPL_AUX_OVERLOAD_CALL_IS_MASKED(
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Map
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, BOOST_MPL_AUX_STATIC_CAST(long_<order>*, 0)
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) ) == sizeof(aux::yes_tag)
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);
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};
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template< typename Map, long order > struct item_by_order
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{
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typedef typename eval_if_c<
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is_item_masked<Map,order>::value
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, void_
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, m_at<Map,(order - 2)>
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>::type type;
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};
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#endif
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}}
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#endif // BOOST_MPL_SET_AUX_AT_IMPL_HPP_INCLUDED
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