Chris@16: 
Chris@16: #ifndef BOOST_MPL_DISTANCE_HPP_INCLUDED
Chris@16: #define BOOST_MPL_DISTANCE_HPP_INCLUDED
Chris@16: 
Chris@16: // Copyright Aleksey Gurtovoy 2000-2004
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. 
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: 
Chris@101: // $Id$
Chris@101: // $Date$
Chris@101: // $Revision$
Chris@16: 
Chris@16: #include <boost/mpl/distance_fwd.hpp>
Chris@16: #include <boost/mpl/iter_fold.hpp>
Chris@16: #include <boost/mpl/iterator_range.hpp>
Chris@16: #include <boost/mpl/long.hpp>
Chris@16: #include <boost/mpl/next.hpp>
Chris@16: #include <boost/mpl/tag.hpp>
Chris@16: #include <boost/mpl/apply_wrap.hpp>
Chris@16: #include <boost/mpl/aux_/msvc_eti_base.hpp>
Chris@16: #include <boost/mpl/aux_/value_wknd.hpp>
Chris@16: #include <boost/mpl/aux_/na_spec.hpp>
Chris@16: #include <boost/mpl/aux_/config/forwarding.hpp>
Chris@16: #include <boost/mpl/aux_/config/static_constant.hpp>
Chris@16: 
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: // default implementation for forward/bidirectional iterators
Chris@16: template< typename Tag > struct distance_impl
Chris@16: {
Chris@16:     template< typename First, typename Last > struct apply
Chris@16: #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
Chris@16:         : aux::msvc_eti_base< typename iter_fold<
Chris@16:               iterator_range<First,Last>
Chris@16:             , mpl::long_<0>
Chris@16:             , next<>
Chris@16:             >::type >
Chris@16:     {
Chris@16: #else
Chris@16:     {
Chris@16:         typedef typename iter_fold<
Chris@16:               iterator_range<First,Last>
Chris@16:             , mpl::long_<0>
Chris@16:             , next<>
Chris@16:             >::type type;
Chris@16:         
Chris@16:         BOOST_STATIC_CONSTANT(long, value =
Chris@16:               (iter_fold<
Chris@16:                   iterator_range<First,Last>
Chris@16:                 , mpl::long_<0>
Chris@16:                 , next<>
Chris@16:                 >::type::value)
Chris@16:             );
Chris@16: #endif
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<
Chris@16:       typename BOOST_MPL_AUX_NA_PARAM(First)
Chris@16:     , typename BOOST_MPL_AUX_NA_PARAM(Last)
Chris@16:     >
Chris@16: struct distance
Chris@16:     : distance_impl< typename tag<First>::type >
Chris@16:         ::template apply<First, Last>
Chris@16: {
Chris@16:     BOOST_MPL_AUX_LAMBDA_SUPPORT(2, distance, (First, Last))
Chris@16: };
Chris@16: 
Chris@16: BOOST_MPL_AUX_NA_SPEC(2, distance)
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_DISTANCE_HPP_INCLUDED