/*=============================================================================
    Copyright (c) 2001-2011 Joel de Guzman
    Copyright (c) 2011 Brandon Kohn

    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)
==============================================================================*/
#if !defined(BOOST_FUSION_MAP_DETAIL_AT_IMPL_HPP)
#define BOOST_FUSION_MAP_DETAIL_AT_IMPL_HPP

#include <boost/fusion/support/config.hpp>
#include <boost/fusion/support/detail/access.hpp>
#include <boost/type_traits/is_const.hpp>
#include <boost/mpl/at.hpp>
#include <boost/mpl/int.hpp>

namespace boost {
namespace fusion {
struct map_tag;

namespace extension {
template <typename Tag>
struct at_impl;

template <>
struct at_impl<map_tag>
{
    template <typename Sequence, typename N>
    struct apply
    {
        typedef typename
        mpl::at<typename Sequence::storage_type::types, N>::type
        element;
        typedef typename detail::ref_result<element>::type type;

        BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
        static type
        call(Sequence& m)
        {
            return m.get_data().at_impl(N());
        }
    };

    template <typename Sequence, typename N>
    struct apply<Sequence const, N>
    {
        typedef typename
        mpl::at<typename Sequence::storage_type::types, N>::type
        element;
        typedef typename detail::cref_result<element>::type type;

        BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
        static type
        call(Sequence const& m)
        {
            return m.get_data().at_impl(N());
        }
    };
};
}
}
}

#endif //BOOST_FUSION_MAP_DETAIL_AT_IMPL_HPP
