Chris@16: /*=============================================================================
Chris@16:     Copyright (c) 2001-2011 Joel de Guzman
Chris@16: 
Chris@16:     Distributed under the Boost Software License, Version 1.0. (See accompanying 
Chris@16:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: ==============================================================================*/
Chris@16: #if !defined(FUSION_DISTANCE_09172005_0730)
Chris@16: #define FUSION_DISTANCE_09172005_0730
Chris@16: 
Chris@101: #include <boost/fusion/support/config.hpp>
Chris@16: #include <boost/mpl/int.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/mpl/eval_if.hpp>
Chris@16: #include <boost/mpl/next.hpp>
Chris@16: #include <boost/mpl/identity.hpp>
Chris@16: #include <boost/fusion/iterator/next.hpp>
Chris@16: #include <boost/fusion/iterator/equal_to.hpp>
Chris@16: 
Chris@16: namespace boost { namespace fusion { namespace distance_detail
Chris@16: {
Chris@16:     // Default distance implementation, linear
Chris@16:     // search for the Last iterator.
Chris@16: 
Chris@16:     template <typename First, typename Last>
Chris@16:     struct linear_distance;
Chris@16: 
Chris@16:     template <typename First, typename Last>
Chris@16:     struct next_distance
Chris@16:     {
Chris@16:         typedef typename 
Chris@16:             mpl::next<
Chris@16:                 typename linear_distance<
Chris@16:                     typename result_of::next<First>::type
Chris@16:                   , Last
Chris@16:                 >::type
Chris@16:             >::type 
Chris@16:         type;
Chris@16:     };
Chris@16: 
Chris@16:     template <typename First, typename Last>
Chris@16:     struct linear_distance
Chris@16:         : mpl::eval_if<
Chris@16:             result_of::equal_to<First, Last>
Chris@16:           , mpl::identity<mpl::int_<0> >
Chris@16:           , next_distance<First, Last>
Chris@16:         >::type
Chris@16:     {
Chris@16:         typedef typename
Chris@16:             mpl::eval_if<
Chris@16:                 result_of::equal_to<First, Last>
Chris@16:               , mpl::identity<mpl::int_<0> >
Chris@16:               , next_distance<First, Last>
Chris@16:             >::type
Chris@16:         type;
Chris@16: 
Chris@101:         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
Chris@16:         static type
Chris@16:         call(First const&, Last const&)
Chris@16:         {
Chris@16:             return type();
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16: }}}
Chris@16: 
Chris@16: #endif