

#ifndef BOOST_MPL_AUX_JOINT_ITER_HPP_INCLUDED

#define BOOST_MPL_AUX_JOINT_ITER_HPP_INCLUDED



// Copyright Aleksey Gurtovoy 2000-2004

//

// 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.



// $Source$

// $Date: 2004-10-01 12:32:41 -0400 (Fri, 01 Oct 2004) $

// $Revision: 25513 $



#include <boost/mpl/next_prior.hpp>

#include <boost/mpl/deref.hpp>

#include <boost/mpl/iterator_tags.hpp>

#include <boost/mpl/aux_/lambda_spec.hpp>

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



#if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)

#   include <boost/type_traits/is_same.hpp>

#endif



namespace boost { namespace mpl {



#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)



template<

      typename Iterator1

    , typename LastIterator1

    , typename Iterator2

    >

struct joint_iter

{

    typedef Iterator1 base;

    typedef forward_iterator_tag category;

};



template<

      typename LastIterator1

    , typename Iterator2

    >

struct joint_iter<LastIterator1,LastIterator1,Iterator2>

{

    typedef Iterator2 base;

    typedef forward_iterator_tag category;

};





template< typename I1, typename L1, typename I2 >

struct deref< joint_iter<I1,L1,I2> >

{

    typedef typename joint_iter<I1,L1,I2>::base base_;

    typedef typename deref<base_>::type type;

};



template< typename I1, typename L1, typename I2 >

struct next< joint_iter<I1,L1,I2> >

{

    typedef joint_iter< typename mpl::next<I1>::type,L1,I2 > type;

};



template< typename L1, typename I2 >

struct next< joint_iter<L1,L1,I2> >

{

    typedef joint_iter< L1,L1,typename mpl::next<I2>::type > type;

};



#else // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION



template<

      typename Iterator1

    , typename LastIterator1

    , typename Iterator2

    >

struct joint_iter;



template< bool > struct joint_iter_impl

{

    template< typename I1, typename L1, typename I2 > struct result_

    {

        typedef I1 base;

        typedef forward_iterator_tag category;

        typedef joint_iter< typename mpl::next<I1>::type,L1,I2 > next;

        typedef typename deref<I1>::type type;

    };

};



template<> struct joint_iter_impl<true>

{

    template< typename I1, typename L1, typename I2 > struct result_

    {

        typedef I2 base;

        typedef forward_iterator_tag category;

        typedef joint_iter< L1,L1,typename mpl::next<I2>::type > next;

        typedef typename deref<I2>::type type;

    };

};



template<

      typename Iterator1

    , typename LastIterator1

    , typename Iterator2

    >

struct joint_iter

    : joint_iter_impl< is_same<Iterator1,LastIterator1>::value >

        ::template result_<Iterator1,LastIterator1,Iterator2>

{

};



#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION



BOOST_MPL_AUX_PASS_THROUGH_LAMBDA_SPEC(3, joint_iter)



}}



#endif // BOOST_MPL_AUX_JOINT_ITER_HPP_INCLUDED

