1 /*============================================================================= 2 Copyright (c) 2001-2011 Joel de Guzman 3 Copyright (c) 2006 Dan Marsden 4 5 Distributed under the Boost Software License, Version 1.0. (See accompanying 6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 7 ==============================================================================*/ 8 #if !defined(FUSION_DEREF_IMPL_20061024_1959) 9 #define FUSION_DEREF_IMPL_20061024_1959 10 11 #include <boost/fusion/support/config.hpp> 12 #include <boost/fusion/container/vector.hpp> 13 #include <boost/fusion/iterator/deref.hpp> 14 #include <boost/fusion/algorithm/transformation/transform.hpp> 15 #include <boost/fusion/container/vector/convert.hpp> 16 #include <boost/fusion/support/unused.hpp> 17 #include <boost/mpl/eval_if.hpp> 18 #include <boost/mpl/identity.hpp> 19 #include <boost/type_traits/is_same.hpp> 20 #include <boost/type_traits/remove_reference.hpp> 21 #include <boost/type_traits/remove_const.hpp> 22 23 namespace boost { namespace fusion { 24 25 struct zip_view_iterator_tag; 26 27 namespace detail 28 { 29 struct poly_deref 30 { 31 template<typename Sig> 32 struct result; 33 34 template<typename It> 35 struct result<poly_deref(It)> 36 { 37 typedef typename remove_const< 38 typename remove_reference<It>::type>::type it; 39 40 typedef typename mpl::eval_if<is_same<it, unused_type>, 41 mpl::identity<unused_type>, 42 result_of::deref<it> >::type type; 43 }; 44 45 template<typename It> 46 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED 47 typename result<poly_deref(It)>::type operator ()boost::fusion::detail::poly_deref48 operator()(const It& it) const 49 { 50 return fusion::deref(it); 51 } 52 53 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED operator ()boost::fusion::detail::poly_deref54 unused_type operator()(unused_type const&) const 55 { 56 return unused_type(); 57 } 58 }; 59 } 60 61 namespace extension 62 { 63 template<typename Tag> 64 struct deref_impl; 65 66 template<> 67 struct deref_impl<zip_view_iterator_tag> 68 { 69 template<typename It> 70 struct apply 71 { 72 typedef typename result_of::as_vector< 73 typename result_of::transform<typename It::iterators, detail::poly_deref>::type>::type type; 74 75 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED 76 static type callboost::fusion::extension::deref_impl::apply77 call(It const& it) 78 { 79 return type( 80 fusion::transform(it.iterators_, detail::poly_deref())); 81 } 82 }; 83 }; 84 } 85 }} 86 87 #endif 88