transform_view/detail/prior_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003     Copyright (c) 2005-2006 Dan Marsden
0004
0005     Distributed under the Boost Software License, Version 1.0. (See accompanying
0006     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0007 ==============================================================================*/
0008 #if !defined(FUSION_PREV_IMPL_13122005_2110)
0009 #define FUSION_PREV_IMPL_13122005_2110
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/fusion/iterator/prior.hpp>
0013
0014 namespace boost { namespace fusion
0015 {
0016     struct transform_view_iterator_tag;
0017     struct transform_view_iterator2_tag;
0018
0019     template<typename First, typename F>
0020     struct transform_view_iterator;
0021
0022     template <typename First1, typename First2, typename F>
0023     struct transform_view_iterator2;
0024
0025     namespace extension
0026     {
0027         template<typename Tag>
0028         struct prior_impl;
0029
0030         // Unary Version
0031         template<>
0032         struct prior_impl<transform_view_iterator_tag>
0033         {
0034             template<typename Iterator>
0035             struct apply
0036             {
0037                 typedef typename Iterator::first_type first_type;
0038                 typedef typename result_of::prior<first_type>::type prior_type;
0039                 typedef typename Iterator::transform_type transform_type;
0040                 typedef transform_view_iterator<prior_type, transform_type> type;
0041
0042                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0043                 static type
0044                 call(Iterator const& i)
0045                 {
0046                     return type(fusion::prior(i.first), i.f);
0047                 }
0048             };
0049         };
0050
0051         // Binary Version
0052         template<>
0053         struct prior_impl<transform_view_iterator2_tag>
0054         {
0055             template<typename Iterator>
0056             struct apply
0057             {
0058                 typedef typename Iterator::first1_type first1_type;
0059                 typedef typename Iterator::first2_type first2_type;
0060                 typedef typename result_of::prior<first1_type>::type prior1_type;
0061                 typedef typename result_of::prior<first2_type>::type prior2_type;
0062                 typedef typename Iterator::transform_type transform_type;
0063                 typedef transform_view_iterator2<prior1_type, prior2_type, transform_type> type;
0064
0065                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0066                 static type
0067                 call(Iterator const& i)
0068                 {
0069                     return type(fusion::prior(i.first1), fusion::prior(i.first2), i.f);
0070                 }
0071             };
0072         };
0073     }
0074 }}
0075
0076 #endif