transform_view/detail/deref_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003     Copyright (c) 2018 Kohei Takahashi
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_DEREF_IMPL_07162005_1026)
0009 #define FUSION_DEREF_IMPL_07162005_1026
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/fusion/iterator/deref.hpp>
0013 #include <boost/utility/result_of.hpp>
0014
0015 namespace boost { namespace fusion
0016 {
0017     struct transform_view_iterator_tag;
0018     struct transform_view_iterator2_tag;
0019
0020     namespace extension
0021     {
0022         template <typename Tag>
0023         struct deref_impl;
0024
0025         // Unary Version
0026         template <>
0027         struct deref_impl<transform_view_iterator_tag>
0028         {
0029             template <typename Iterator>
0030             struct apply
0031             {
0032                 typedef typename
0033                     result_of::deref<typename Iterator::first_type>::type
0034                 value_type;
0035
0036                 typedef typename Iterator::transform_type F;
0037                 typedef typename boost::result_of<F(value_type)>::type type;
0038
0039                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0040                 static type
0041                 call(Iterator const& i)
0042                 {
0043                     return i.f(*i.first);
0044                 }
0045             };
0046         };
0047
0048         // Binary Version
0049         template <>
0050         struct deref_impl<transform_view_iterator2_tag>
0051         {
0052             template <typename Iterator>
0053             struct apply
0054             {
0055                 typedef typename
0056                     result_of::deref<typename Iterator::first1_type>::type
0057                 value1_type;
0058                 typedef typename
0059                     result_of::deref<typename Iterator::first2_type>::type
0060                 value2_type;
0061
0062                 typedef typename Iterator::transform_type F;
0063                 typedef typename boost::result_of<F(value1_type, value2_type)>::type type;
0064
0065                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0066                 static type
0067                 call(Iterator const& i)
0068                 {
0069                     return i.f(*i.first1, *i.first2);
0070                 }
0071             };
0072         };
0073     }
0074 }}
0075
0076 #endif
0077
0078