boost/fusion/view/filter_view/filter_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_SEQUENCE_FILTER_VIEW_HPP)
   8 #define FUSION_SEQUENCE_FILTER_VIEW_HPP
   9
  10 #include <boost/fusion/support/config.hpp>
  11 #include <boost/fusion/support/detail/access.hpp>
  12 #include <boost/fusion/support/sequence_base.hpp>
  13 #include <boost/fusion/support/is_view.hpp>
  14 #include <boost/fusion/view/filter_view/filter_view_iterator.hpp>
  15 #include <boost/fusion/view/filter_view/detail/begin_impl.hpp>
  16 #include <boost/fusion/view/filter_view/detail/end_impl.hpp>
  17 #include <boost/fusion/view/filter_view/detail/size_impl.hpp>
  18 #include <boost/fusion/sequence/intrinsic/begin.hpp>
  19 #include <boost/fusion/sequence/intrinsic/end.hpp>
  20 #include <boost/mpl/bool.hpp>
  21 #include <boost/mpl/eval_if.hpp>
  22 #include <boost/mpl/inherit.hpp>
  23 #include <boost/mpl/identity.hpp>
  24
  25 namespace boost { namespace fusion
  26 {
  27     struct filter_view_tag;
  28     struct forward_traversal_tag;
  29     struct fusion_sequence_tag;
  30
  31     template <typename Sequence, typename Pred>
  32     struct filter_view : sequence_base<filter_view<Sequence, Pred> >
  33     {
  34         typedef filter_view_tag fusion_tag;
  35         typedef fusion_sequence_tag tag; // this gets picked up by MPL
  36         typedef typename
  37             mpl::eval_if<
  38                 traits::is_associative<Sequence>
  39               , mpl::inherit2<forward_traversal_tag,associative_tag>
  40               , mpl::identity<forward_traversal_tag>
  41             >::type
  42         category;
  43         typedef mpl::true_ is_view;
  44
  45         typedef typename result_of::begin<Sequence>::type first_type;
  46         typedef typename result_of::end<Sequence>::type last_type;
  47         typedef Pred pred_type;
  48
  49         BOOST_FUSION_GPU_ENABLED
  50         filter_view(Sequence& in_seq)
  51             : seq(in_seq)
  52         {}
  53
  54         BOOST_FUSION_GPU_ENABLED
  55         first_type first() const { return fusion::begin(seq); }
  56         BOOST_FUSION_GPU_ENABLED
  57         last_type last() const { return fusion::end(seq); }
  58         typename mpl::if_<traits::is_view<Sequence>, Sequence, Sequence&>::type seq;
  59
  60     private:
  61         // silence MSVC warning C4512: assignment operator could not be generated
  62         filter_view& operator= (filter_view const&);
  63     };
  64 }}
  65
  66 #endif
  67
  68