reverse_view/detail/deref_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
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 #if !defined(FUSION_DEREF_IMPL_07202005_0851)
0008 #define FUSION_DEREF_IMPL_07202005_0851
0009
0010 #include <boost/fusion/support/config.hpp>
0011 #include <boost/fusion/iterator/deref.hpp>
0012 #include <boost/fusion/iterator/prior.hpp>
0013
0014 namespace boost { namespace fusion
0015 {
0016     struct reverse_view_iterator_tag;
0017
0018     namespace extension
0019     {
0020         template <typename Tag>
0021         struct deref_impl;
0022
0023         template <>
0024         struct deref_impl<reverse_view_iterator_tag>
0025         {
0026             template <typename Iterator>
0027             struct apply
0028             {
0029                 typedef typename
0030                     result_of::deref<
0031                         typename result_of::prior<
0032                             typename Iterator::first_type
0033                         >::type
0034                     >::type
0035                 type;
0036
0037                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0038                 static type
0039                 call(Iterator const& i)
0040                 {
0041                     return *fusion::prior(i.first);
0042                 }
0043             };
0044         };
0045     }
0046 }}
0047
0048 #endif
0049
0050