boost/fusion/view/joint_view/joint_view.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 ==============================================================================*/
   7 #if !defined(FUSION_JOINT_VIEW_07162005_0140)
   8 #define FUSION_JOINT_VIEW_07162005_0140
   9
  10 #include <boost/fusion/view/joint_view/joint_view_fwd.hpp>
  11 #include <boost/fusion/support/detail/access.hpp>
  12 #include <boost/fusion/support/is_view.hpp>
  13 #include <boost/fusion/sequence/intrinsic/begin.hpp>
  14 #include <boost/fusion/sequence/intrinsic/end.hpp>
  15 #include <boost/fusion/sequence/intrinsic/size.hpp>
  16 #include <boost/fusion/view/joint_view/joint_view_iterator.hpp>
  17 #include <boost/fusion/view/joint_view/detail/begin_impl.hpp>
  18 #include <boost/fusion/view/joint_view/detail/end_impl.hpp>
  19 #include <boost/fusion/support/sequence_base.hpp>
  20 #include <boost/mpl/if.hpp>
  21 #include <boost/mpl/plus.hpp>
  22 #include <boost/mpl/bool.hpp>
  23 #include <boost/mpl/eval_if.hpp>
  24 #include <boost/mpl/inherit.hpp>
  25 #include <boost/mpl/identity.hpp>
  26
  27 namespace boost { namespace fusion
  28 {
  29     struct joint_view_tag;
  30     struct forward_traversal_tag;
  31     struct fusion_sequence_tag;
  32
  33     template <typename Sequence1, typename Sequence2>
  34     struct joint_view : sequence_base<joint_view<Sequence1, Sequence2> >
  35     {
  36         typedef joint_view_tag fusion_tag;
  37         typedef fusion_sequence_tag tag; // this gets picked up by MPL
  38         typedef typename
  39             mpl::eval_if<
  40                 mpl::and_<
  41                     traits::is_associative<Sequence1>
  42                   , traits::is_associative<Sequence2>
  43                 >
  44               , mpl::inherit2<forward_traversal_tag,associative_tag>
  45               , mpl::identity<forward_traversal_tag>
  46             >::type
  47         category;
  48         typedef mpl::true_ is_view;
  49
  50         typedef typename result_of::begin<Sequence1>::type first_type;
  51         typedef typename result_of::end<Sequence1>::type last_type;
  52         typedef typename result_of::begin<Sequence2>::type concat_type;
  53         typedef typename result_of::end<Sequence2>::type concat_last_type;
  54         typedef typename mpl::int_<
  55             result_of::size<Sequence1>::value + result_of::size<Sequence2>::value>
  56         size;
  57
  58         joint_view(Sequence1& in_seq1, Sequence2& in_seq2)
  59             : seq1(in_seq1)
  60             , seq2(in_seq2)
  61         {}
  62
  63         first_type first() const { return fusion::begin(seq1); }
  64         concat_type concat() const { return fusion::begin(seq2); }
  65         concat_last_type concat_last() const { return fusion::end(seq2); }
  66
  67     private:
  68         // silence MSVC warning C4512: assignment operator could not be generated
  69         joint_view& operator= (joint_view const&);
  70
  71         typename mpl::if_<traits::is_view<Sequence1>, Sequence1, Sequence1&>::type seq1;
  72         typename mpl::if_<traits::is_view<Sequence2>, Sequence2, Sequence2&>::type seq2;
  73     };
  74 }}
  75
  76 #endif
  77
  78