1 /*============================================================================= 2 Copyright (c) 2001-2006 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_ZIP_VIEW_23012006_0813) 9 #define FUSION_ZIP_VIEW_23012006_0813 10 11 #include <boost/fusion/support/sequence_base.hpp> 12 #include <boost/fusion/support/unused.hpp> 13 #include <boost/fusion/iterator/equal_to.hpp> 14 #include <boost/fusion/view/detail/strictest_traversal.hpp> 15 #include <boost/fusion/view/zip_view/detail/begin_impl.hpp> 16 #include <boost/fusion/view/zip_view/detail/end_impl.hpp> 17 #include <boost/fusion/view/zip_view/detail/size_impl.hpp> 18 #include <boost/fusion/view/zip_view/detail/at_impl.hpp> 19 #include <boost/fusion/view/zip_view/detail/value_at_impl.hpp> 20 #include <boost/fusion/container/vector/convert.hpp> 21 #include <boost/fusion/algorithm/query/find_if.hpp> 22 #include <boost/fusion/sequence/intrinsic/end.hpp> 23 #include <boost/fusion/sequence/intrinsic/size.hpp> 24 #include <boost/fusion/mpl.hpp> 25 #include <boost/fusion/algorithm/transformation/remove.hpp> 26 27 #include <boost/mpl/assert.hpp> 28 #include <boost/mpl/not.hpp> 29 #include <boost/mpl/placeholders.hpp> 30 #include <boost/mpl/transform_view.hpp> 31 #include <boost/mpl/at.hpp> 32 #include <boost/mpl/find_if.hpp> 33 #include <boost/mpl/equal_to.hpp> 34 #include <boost/mpl/bool.hpp> 35 #include <boost/mpl/eval_if.hpp> 36 37 #include <boost/type_traits/remove_reference.hpp> 38 #include <boost/type_traits/is_reference.hpp> 39 40 namespace boost { namespace fusion { 41 42 namespace detail 43 { 44 template<typename Sequences> 45 struct all_references 46 : fusion::result_of::equal_to<typename fusion::result_of::find_if<Sequences, mpl::not_<is_reference<mpl::_> > >::type, typename fusion::result_of::end<Sequences>::type> 47 {}; 48 49 struct seq_ref_size 50 { 51 template<typename Params> 52 struct result; 53 54 template<typename Seq> 55 struct result<seq_ref_size(Seq)> 56 { 57 static int const high_int = static_cast<int>( 58 (static_cast<unsigned>(~0) >> 1) - 1); 59 60 typedef typename remove_reference<Seq>::type SeqClass; 61 62 typedef typename mpl::eval_if< 63 traits::is_forward<SeqClass>, 64 result_of::size<SeqClass>, 65 mpl::int_<high_int> >::type type; 66 }; 67 }; 68 69 struct poly_min 70 { 71 template<typename T> 72 struct result; 73 74 template<typename Lhs, typename Rhs> 75 struct result<poly_min(Lhs, Rhs)> 76 { 77 typedef typename remove_reference<Lhs>::type lhs; 78 typedef typename remove_reference<Rhs>::type rhs; 79 typedef typename mpl::min<lhs, rhs>::type type; 80 }; 81 }; 82 83 template<typename Sequences> 84 struct min_size 85 { 86 typedef typename result_of::transform<Sequences, detail::seq_ref_size>::type sizes; 87 typedef typename result_of::fold<sizes, typename result_of::front<sizes>::type, detail::poly_min>::type type; 88 }; 89 } 90 91 struct zip_view_tag; 92 struct fusion_sequence_tag; 93 94 template<typename Sequences> 95 struct zip_view : sequence_base< zip_view<Sequences> > 96 { 97 typedef typename result_of::remove<Sequences, unused_type const&>::type real_sequences; 98 BOOST_MPL_ASSERT((detail::all_references<Sequences>)); 99 typedef typename detail::strictest_traversal<real_sequences>::type category; 100 typedef zip_view_tag fusion_tag; 101 typedef fusion_sequence_tag tag; // this gets picked up by MPL 102 typedef mpl::true_ is_view; 103 typedef typename fusion::result_of::as_vector<Sequences>::type sequences; 104 typedef typename detail::min_size<real_sequences>::type size; 105 zip_viewboost::fusion::zip_view106 zip_view( 107 const Sequences& seqs) 108 : sequences_(seqs) 109 {}; 110 111 sequences sequences_; 112 }; 113 }} 114 115 #endif 116