/*=============================================================================

    Copyright (c) 2001-2006 Joel de Guzman

    Copyright (c) 2006 Dan Marsden



    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_ZIP_VIEW_23012006_0813)

#define FUSION_ZIP_VIEW_23012006_0813



#include <boost/fusion/support/sequence_base.hpp>

#include <boost/fusion/support/unused.hpp>

#include <boost/fusion/iterator/equal_to.hpp>

#include <boost/fusion/view/detail/strictest_traversal.hpp>

#include <boost/fusion/view/zip_view/detail/begin_impl.hpp>

#include <boost/fusion/view/zip_view/detail/end_impl.hpp>

#include <boost/fusion/view/zip_view/detail/size_impl.hpp>

#include <boost/fusion/view/zip_view/detail/at_impl.hpp>

#include <boost/fusion/view/zip_view/detail/value_at_impl.hpp>

#include <boost/fusion/container/vector/convert.hpp>

#include <boost/fusion/algorithm/query/find_if.hpp>

#include <boost/fusion/sequence/intrinsic/end.hpp>

#include <boost/fusion/sequence/intrinsic/size.hpp>

#include <boost/fusion/mpl.hpp>

#include <boost/fusion/algorithm/transformation/remove.hpp>



#include <boost/mpl/assert.hpp>

#include <boost/mpl/not.hpp>

#include <boost/mpl/placeholders.hpp>

#include <boost/mpl/transform_view.hpp>

#include <boost/mpl/at.hpp>

#include <boost/mpl/find_if.hpp>

#include <boost/mpl/equal_to.hpp>

#include <boost/mpl/bool.hpp>

#include <boost/mpl/eval_if.hpp>



#include <boost/type_traits/remove_reference.hpp>

#include <boost/type_traits/is_reference.hpp>



namespace boost { namespace fusion {



    namespace detail

    {

        template<typename Sequences>

        struct all_references

            : fusion::result_of::equal_to<typename fusion::result_of::find_if<Sequences, mpl::not_<is_reference<mpl::_> > >::type, typename fusion::result_of::end<Sequences>::type>

        {};



        struct seq_ref_size

        {

            template<typename Params>

            struct result;



            template<typename Seq>

            struct result<seq_ref_size(Seq)>

            {

                static int const high_int = static_cast<int>(

                    (static_cast<unsigned>(~0) >> 1) - 1);



                typedef typename remove_reference<Seq>::type SeqClass;



                typedef typename mpl::eval_if<

                    traits::is_forward<SeqClass>,

                    result_of::size<SeqClass>,

                    mpl::int_<high_int> >::type type;

            };

        };



        struct poly_min

        {

            template<typename T>

            struct result;



            template<typename Lhs, typename Rhs>

            struct result<poly_min(Lhs, Rhs)>

            {

                typedef typename remove_reference<Lhs>::type lhs;

                typedef typename remove_reference<Rhs>::type rhs;

                typedef typename mpl::min<lhs, rhs>::type type;

            };

        };



        template<typename Sequences>

        struct min_size

        {

            typedef typename result_of::transform<Sequences, detail::seq_ref_size>::type sizes;

            typedef typename result_of::fold<sizes, typename result_of::front<sizes>::type, detail::poly_min>::type type;

        };

    }



    struct zip_view_tag;

    struct fusion_sequence_tag;



    template<typename Sequences>

    struct zip_view : sequence_base< zip_view<Sequences> >

    {

        typedef typename result_of::remove<Sequences, unused_type const&>::type real_sequences;

        BOOST_MPL_ASSERT((detail::all_references<Sequences>));

        typedef typename detail::strictest_traversal<real_sequences>::type category;

        typedef zip_view_tag fusion_tag;

        typedef fusion_sequence_tag tag; // this gets picked up by MPL

        typedef mpl::true_ is_view;

        typedef typename fusion::result_of::as_vector<Sequences>::type sequences;

        typedef typename detail::min_size<real_sequences>::type size;



        zip_view(

            const Sequences& seqs)

            : sequences_(seqs)

        {};



        sequences sequences_;

    };

}}



#endif

