transform_view/detail/deref_data_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2022 Denis Mikhailov
0003     Distributed under the Boost Software License, Version 1.0. (See accompanying
0004     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0005 ==============================================================================*/
0006
0007 #if !defined(BOOST_FUSION_TRANSFORM_VIEW_DEREF_DATA_IMPL_JAN_9_2022_0354PM)
0008 #define BOOST_FUSION_TRANSFORM_VIEW_DEREF_DATA_IMPL_JAN_9_2022_0354PM
0009
0010 #include <boost/fusion/support/config.hpp>
0011 #include <boost/fusion/iterator/deref.hpp>
0012 #include <boost/type_traits/remove_reference.hpp>
0013 #include <boost/type_traits/remove_const.hpp>
0014 #include <boost/type_traits/add_reference.hpp>
0015 #include <boost/type_traits/add_const.hpp>
0016 #include <boost/type_traits/is_reference.hpp>
0017 #include <boost/type_traits/is_const.hpp>
0018 #include <boost/utility/result_of.hpp>
0019 #include <boost/mpl/if.hpp>
0020
0021 namespace boost { namespace fusion
0022 {
0023     struct transform_view_iterator_tag;
0024     struct transform_view_iterator2_tag;
0025
0026     namespace extension
0027     {
0028         template<typename Tag>
0029         struct deref_data_impl;
0030
0031         // Unary Version
0032         template<>
0033         struct deref_data_impl<transform_view_iterator_tag>
0034         {
0035             template <typename Iterator>
0036             struct apply
0037             {
0038                 typedef typename
0039                     result_of::deref<typename Iterator::first_type>::type
0040                 value_type;
0041
0042                 typedef typename Iterator::transform_type F;
0043                 typedef typename boost::result_of<F(value_type)>::type transformed_type;
0044                 typedef typename boost::remove_reference<transformed_type>::type transformed_type_unref;
0045                 typedef typename boost::remove_const<transformed_type_unref>::type transformed_type_unconst;
0046
0047                 typedef typename transformed_type_unconst::second_type raw_type;
0048                 typedef typename
0049                     boost::mpl::if_<
0050                         is_reference<transformed_type>
0051                       , typename boost::mpl::if_<
0052                             is_const<transformed_type_unref>
0053                             , typename boost::add_reference<typename boost::add_const<raw_type>::type>::type
0054                             , typename boost::add_reference<raw_type>::type
0055                         >::type
0056                       , raw_type
0057                     >::type
0058                 type;
0059
0060                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0061                 static type
0062                 call(Iterator const& i)
0063                 {
0064                     return i.f(fusion::deref(i.first)).second;
0065                 }
0066             };
0067         };
0068
0069         // Binary Version is not supported with Associative Sequence
0070     }
0071 }}
0072
0073 #endif