ceph/src/boost/libs/fusion/include/boost/fusion/view/zip_view/zip_view.hpp

   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_ZIP_VIEW_23012006_0813)
   9 #define FUSION_ZIP_VIEW_23012006_0813
  10
  11 #include <boost/fusion/support/config.hpp>
  12 #include <boost/fusion/support/sequence_base.hpp>
  13 #include <boost/fusion/support/unused.hpp>
  14 #include <boost/fusion/iterator/equal_to.hpp>
  15 #include <boost/fusion/view/detail/strictest_traversal.hpp>
  16 #include <boost/fusion/view/zip_view/detail/begin_impl.hpp>
  17 #include <boost/fusion/view/zip_view/detail/end_impl.hpp>
  18 #include <boost/fusion/view/zip_view/detail/size_impl.hpp>
  19 #include <boost/fusion/view/zip_view/detail/at_impl.hpp>
  20 #include <boost/fusion/view/zip_view/detail/value_at_impl.hpp>
  21 #include <boost/fusion/container/vector/convert.hpp>
  22 #include <boost/fusion/algorithm/query/find_if.hpp>
  23 #include <boost/fusion/sequence/intrinsic/end.hpp>
  24 #include <boost/fusion/sequence/intrinsic/size.hpp>
  25 #include <boost/fusion/mpl.hpp>
  26 #include <boost/fusion/algorithm/transformation/remove.hpp>
  27
  28 #include <boost/mpl/assert.hpp>
  29 #include <boost/mpl/not.hpp>
  30 #include <boost/mpl/placeholders.hpp>
  31 #include <boost/mpl/transform_view.hpp>
  32 #include <boost/mpl/at.hpp>
  33 #include <boost/mpl/find_if.hpp>
  34 #include <boost/mpl/equal_to.hpp>
  35 #include <boost/mpl/bool.hpp>
  36 #include <boost/mpl/eval_if.hpp>
  37
  38 #include <boost/type_traits/remove_reference.hpp>
  39 #include <boost/type_traits/is_reference.hpp>
  40
  41 #include <boost/config.hpp>
  42
  43 namespace boost { namespace fusion {
  44
  45     namespace detail
  46     {
  47         template<typename Sequences>
  48         struct all_references
  49             : 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>
  50         {};
  51
  52         struct seq_ref_size
  53         {
  54             template<typename Params>
  55             struct result;
  56
  57             template<typename Seq>
  58             struct result<seq_ref_size(Seq)>
  59             {
  60                 static int const high_int = static_cast<int>(
  61                     (static_cast<unsigned>(~0) >> 1) - 1);
  62
  63                 typedef typename remove_reference<Seq>::type SeqClass;
  64
  65                 typedef typename mpl::eval_if<
  66                     traits::is_forward<SeqClass>,
  67                     result_of::size<SeqClass>,
  68                     mpl::int_<high_int> >::type type;
  69             };
  70
  71             // never called, but needed for decltype-based result_of (C++0x)
  72 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
  73             template<typename Seq>
  74             BOOST_FUSION_GPU_ENABLED
  75             typename result<seq_ref_size(Seq)>::type
  76             operator()(Seq&&) const;
  77 #endif
  78         };
  79
  80         struct poly_min
  81         {
  82             template<typename T>
  83             struct result;
  84
  85             template<typename Lhs, typename Rhs>
  86             struct result<poly_min(Lhs, Rhs)>
  87             {
  88                 typedef typename remove_reference<Lhs>::type lhs;
  89                 typedef typename remove_reference<Rhs>::type rhs;
  90                 typedef typename mpl::min<lhs, rhs>::type type;
  91             };
  92
  93             // never called, but needed for decltype-based result_of (C++0x)
  94 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
  95             template<typename Lhs, typename Rhs>
  96             BOOST_FUSION_GPU_ENABLED
  97             typename result<poly_min(Lhs, Rhs)>::type
  98             operator()(Lhs&&, Rhs&&) const;
  99 #endif
 100         };
 101
 102         template<typename Sequences>
 103         struct min_size
 104         {
 105             typedef typename result_of::transform<Sequences, detail::seq_ref_size>::type sizes;
 106             typedef typename result_of::fold<sizes, typename result_of::front<sizes>::type, detail::poly_min>::type type;
 107         };
 108     }
 109
 110     struct zip_view_tag;
 111     struct fusion_sequence_tag;
 112
 113     template<typename Sequences>
 114     struct zip_view : sequence_base< zip_view<Sequences> >
 115     {
 116         typedef typename result_of::remove<Sequences, unused_type const&>::type real_sequences;
 117         BOOST_MPL_ASSERT((detail::all_references<Sequences>));
 118         typedef typename detail::strictest_traversal<real_sequences>::type category;
 119         typedef zip_view_tag fusion_tag;
 120         typedef fusion_sequence_tag tag; // this gets picked up by MPL
 121         typedef mpl::true_ is_view;
 122         typedef typename fusion::result_of::as_vector<Sequences>::type sequences;
 123         typedef typename detail::min_size<real_sequences>::type size;
 124
 125         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
 126         zip_view(
 127             const Sequences& seqs)
 128             : sequences_(seqs)
 129         {}
 130
 131         sequences sequences_;
 132     };
 133 }}
 134
 135 #endif