/*=============================================================================
    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_ITERATOR_FACADE_09252006_1011)
#define FUSION_ITERATOR_FACADE_09252006_1011

#include <boost/fusion/support/config.hpp>
#include <boost/fusion/support/iterator_base.hpp>
#include <boost/fusion/iterator/detail/advance.hpp>
#include <boost/fusion/iterator/detail/distance.hpp>
#include <boost/fusion/support/category_of.hpp>
#include <boost/type_traits/is_same.hpp>
#include <boost/mpl/assert.hpp>
#include <boost/mpl/if.hpp>

namespace boost {
namespace fusion {
struct iterator_facade_tag;

template <typename Derived, typename Category>
struct iterator_facade : iterator_base<Derived>
{
    typedef iterator_facade_tag fusion_tag;
    typedef Derived derived_type;
    typedef Category category;

    // default implementation
    template <typename I1, typename I2>
    struct equal_to // default implementation
        : is_same<
          typename I1::derived_type
        , typename I2::derived_type
        >
    {};

    // default implementation
    template <typename Iterator, typename N>
    struct advance :
        mpl::if_c<
    (N::value > 0)
    , advance_detail::forward<Iterator, N::value>
    , advance_detail::backward<Iterator, N::value>
    >::type
    {
        BOOST_MPL_ASSERT_NOT((traits::is_random_access<Iterator>));
    };

    // default implementation
    template <typename First, typename Last>
    struct distance :
        distance_detail::linear_distance<First, Last>
    {};
};
}
}

#ifdef BOOST_FUSION_WORKAROUND_FOR_LWG_2408
namespace std {
template <typename Derived, typename Category>
struct iterator_traits< ::boost::fusion::iterator_facade<Derived, Category> >
{ };
}
#endif

#endif
