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#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.
// $Id$
// $Date$
// $Revision$
#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