nview/detail/distance_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2009 Hartmut Kaiser
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 ==============================================================================*/
0007
0008 #if !defined(BOOST_FUSION_NVIEW_DISTANCE_IMPL_SEP_23_2009_0328PM)
0009 #define BOOST_FUSION_NVIEW_DISTANCE_IMPL_SEP_23_2009_0328PM
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/fusion/iterator/distance.hpp>
0013
0014 namespace boost { namespace fusion
0015 {
0016     struct nview_iterator_tag;
0017
0018     namespace extension
0019     {
0020         template<typename Tag>
0021         struct distance_impl;
0022
0023         template<>
0024         struct distance_impl<nview_iterator_tag>
0025         {
0026             template<typename First, typename Last>
0027             struct apply
0028               : result_of::distance<typename First::first_type, typename Last::first_type>
0029             {
0030                 typedef typename result_of::distance<
0031                     typename First::first_type, typename Last::first_type
0032                 >::type type;
0033
0034                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0035                 static type
0036                 call(First const& /*first*/, Last const& /*last*/)
0037                 {
0038                     return type();
0039                 }
0040             };
0041         };
0042     }
0043
0044 }}
0045
0046 #endif