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

    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(FUSION_SIZE_05052005_0214)
#define FUSION_SIZE_05052005_0214

#include <boost/fusion/support/config.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/int.hpp>
#include <boost/fusion/sequence/intrinsic_fwd.hpp>
#include <boost/fusion/support/tag_of.hpp>
#include <boost/fusion/support/is_segmented.hpp>
#include <boost/fusion/sequence/intrinsic/detail/segmented_size.hpp>

namespace boost {
namespace fusion {
// Special tags:
struct sequence_facade_tag;
struct boost_tuple_tag; // boost::tuples::tuple tag
struct boost_array_tag; // boost::array tag
struct mpl_sequence_tag; // mpl sequence tag
struct std_pair_tag; // std::pair tag

namespace extension {
template <typename Tag>
struct size_impl
{
    template<typename Sequence>
    struct unsegmented_size : Sequence::size {};

    template <typename Sequence>
    struct apply
        : mpl::if_<
          traits::is_segmented<Sequence>
        , detail::segmented_size<Sequence>
        , unsegmented_size<Sequence>
        >::type
    {};
};

template <>
struct size_impl<sequence_facade_tag>
{
    template <typename Sequence>
    struct apply : Sequence::template size<Sequence> {};
};

template <>
struct size_impl<boost_tuple_tag>;

template <>
struct size_impl<boost_array_tag>;

template <>
struct size_impl<mpl_sequence_tag>;

template <>
struct size_impl<std_pair_tag>;
}

namespace result_of {
template <typename Sequence>
struct size
    : mpl::int_<
      extension::size_impl<typename detail::tag_of<Sequence>::type>
      ::template apply<Sequence>::type::value
> {};
}

template <typename Sequence>
BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
inline typename result_of::size<Sequence>::type
size(Sequence const&)
{
    typedef typename result_of::size<Sequence>::type result;
    return result();
}
}
}

#endif
