#ifndef BOOST_MPL_DISTANCE_HPP_INCLUDED

#define BOOST_MPL_DISTANCE_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.

// $Id: distance.hpp 49267 2008-10-11 06:19:02Z agurtovoy $

// $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $

// $Revision: 49267 $

#include <boost/mpl/distance_fwd.hpp>

#include <boost/mpl/iter_fold.hpp>

#include <boost/mpl/iterator_range.hpp>

#include <boost/mpl/long.hpp>

#include <boost/mpl/next.hpp>

#include <boost/mpl/tag.hpp>

#include <boost/mpl/apply_wrap.hpp>

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

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

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

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

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

namespace boost { namespace mpl {

// default implementation for forward/bidirectional iterators

template< typename Tag > struct distance_impl

{

    template< typename First, typename Last > struct apply

#if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)

        : aux::msvc_eti_base< typename iter_fold<

              iterator_range<First,Last>

            , mpl::long_<0>

            , next<>

            >::type >

    {

#else

    {

        typedef typename iter_fold<

              iterator_range<First,Last>

            , mpl::long_<0>

            , next<>

            >::type type;

        BOOST_STATIC_CONSTANT(long, value =

              (iter_fold<

                  iterator_range<First,Last>

                , mpl::long_<0>

                , next<>

                >::type::value)

            );

#endif

    };

};

template<

      typename BOOST_MPL_AUX_NA_PARAM(First)

    , typename BOOST_MPL_AUX_NA_PARAM(Last)

    >

struct distance

    : distance_impl< typename tag<First>::type >

        ::template apply<First, Last>

{

    BOOST_MPL_AUX_LAMBDA_SUPPORT(2, distance, (First, Last))

};

BOOST_MPL_AUX_NA_SPEC(2, distance)

}}

#endif // BOOST_MPL_DISTANCE_HPP_INCLUDED