forked from boostorg/fusion
100 lines
2.2 KiB
C++
100 lines
2.2 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2006 Joel de Guzman
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#if !defined(FUSION_LOOKUP_KEY_07222005_1248)
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#define FUSION_LOOKUP_KEY_07222005_1248
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#include <boost/mpl/int.hpp>
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#include <boost/type_traits/add_const.hpp>
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#include <boost/type_traits/add_reference.hpp>
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#include <boost/fusion/support/detail/unknown_key.hpp>
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namespace boost { namespace fusion
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{
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struct void_;
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}}
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namespace boost { namespace fusion { namespace detail
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{
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template <typename T>
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struct map_data_type
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{
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typedef typename
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add_reference<
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typename T::second_type
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>::type
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type;
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};
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template <>
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struct map_data_type<void_>
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{
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typedef void_& type;
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};
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template <typename T>
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struct map_const_data_type
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{
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typedef typename
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add_reference<
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typename add_const<
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typename T::second_type
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>::type
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>::type
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type;
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};
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template <>
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struct map_const_data_type<void_>
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{
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typedef void_ const& type;
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};
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template <typename T>
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struct map_value_type
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{
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typedef typename T::second_type type;
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};
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template <>
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struct map_value_type<void_>
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{
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typedef void_ type;
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};
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template <typename T, int index>
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struct map_key_type
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{
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typedef typename T::first_type type;
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};
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template <int index>
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struct map_key_type<void_, index>
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{
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typedef unknown_key<index> type;
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};
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template <int index, typename RT, typename Key, typename Vector>
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struct map_lookup_key
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{
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static RT
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call(Vector& vec)
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{
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return vec.at_impl(mpl::int_<index>()).second;
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}
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};
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template <int index, typename Vector>
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struct map_lookup_key<index, void_&, unknown_key<index>, Vector>
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{
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static void_&
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call(Vector& vec); // intentionally undefined
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};
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}}}
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#endif
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