#ifndef BOOST_MPL_SET_AUX_ITERATOR_HPP_INCLUDED

#define BOOST_MPL_SET_AUX_ITERATOR_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.

// $Source: /cvsroot/boost/boost/boost/mpl/set/aux_/iterator.hpp,v $

// $Date: 2005/06/18 22:03:09 $

// $Revision: 1.4 $

#include <boost/mpl/set/aux_/set0.hpp>

#include <boost/mpl/has_key.hpp>

#include <boost/mpl/iterator_tags.hpp>

#include <boost/mpl/next.hpp>

#include <boost/mpl/eval_if.hpp>

#include <boost/mpl/if.hpp>

#include <boost/mpl/identity.hpp>

#include <boost/mpl/aux_/config/ctps.hpp>

namespace boost { namespace mpl {

// used by 's_iter_impl'

template< typename Set, typename Tail > struct s_iter;

template< typename Set, typename Tail > struct s_iter_impl

{

    typedef Tail                        tail_;

    typedef forward_iterator_tag        category;

    typedef typename Tail::item_::type  type;

#if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)

    typedef typename eval_if< 

          has_key< Set,typename Tail::next_::type >

        , identity< s_iter<Set,typename Tail::next_> >

        , next< s_iter<Set,typename Tail::next_> >

        >::type next;        

#endif

};

#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)

template< typename Set, typename Tail > 

struct next< s_iter<Set,Tail> >

    : eval_if< 

          has_key< Set,typename Tail::next_::type >

        , identity< s_iter<Set,typename Tail::next_> >

        , next< s_iter<Set,typename Tail::next_> >

        >

{

};

template< typename Set > 

struct next< s_iter<Set,set0<> > >

{

    typedef s_iter<Set,set0<> > type;

};

template< typename Set, typename Tail > struct s_iter

    : s_iter_impl<Set,Tail>

{

};

template< typename Set > struct s_iter<Set, set0<> >

{

    typedef forward_iterator_tag category;

};

#else

template< typename Set >

struct s_end_iter

{

    typedef forward_iterator_tag    category;

    typedef s_iter<Set,set0<> >     next;

};

template< typename Set, typename Tail > struct s_iter

    : if_< 

          is_same< Tail,set0<> >

        , s_end_iter<Set>

        , s_iter_impl<Set,Tail>

        >::type

{

};

#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

}}

#endif // BOOST_MPL_SET_AUX_ITERATOR_HPP_INCLUDED