3rdparty/boost/boost/fusion/view/joint_view/detail/next_impl.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_NEXT_IMPL_07162005_0136)
   8 #define FUSION_NEXT_IMPL_07162005_0136
   9
  10 #include <boost/fusion/support/config.hpp>
  11 #include <boost/fusion/iterator/next.hpp>
  12 #include <boost/fusion/iterator/equal_to.hpp>
  13 #include <boost/mpl/if.hpp>
  14
  15 namespace boost { namespace fusion
  16 {
  17     struct joint_view_iterator_tag;
  18
  19     template <typename Category, typename First, typename Last, typename Concat>
  20     struct joint_view_iterator;
  21
  22     namespace extension
  23     {
  24         template <typename Tag>
  25         struct next_impl;
  26
  27         template <>
  28         struct next_impl<joint_view_iterator_tag>
  29         {
  30             template <typename Iterator>
  31             struct apply
  32             {
  33                 typedef typename Iterator::first_type first_type;
  34                 typedef typename Iterator::last_type last_type;
  35                 typedef typename Iterator::concat_type concat_type;
  36                 typedef typename Iterator::category category;
  37                 typedef typename result_of::next<first_type>::type next_type;
  38                 typedef result_of::equal_to<next_type, last_type> equal_to;
  39
  40                 typedef typename
  41                     mpl::if_<
  42                         equal_to
  43                       , concat_type
  44                       , joint_view_iterator<category, next_type, last_type, concat_type>
  45                     >::type
  46                 type;
  47
  48                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  49                 static type
  50                 call(Iterator const& i, mpl::true_)
  51                 {
  52                     return i.concat;
  53                 }
  54
  55                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  56                 static type
  57                 call(Iterator const& i, mpl::false_)
  58                 {
  59                     return type(fusion::next(i.first), i.concat);
  60                 }
  61
  62                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  63                 static type
  64                 call(Iterator const& i)
  65                 {
  66                     return call(i, equal_to());
  67                 }
  68             };
  69         };
  70     }
  71 }}
  72
  73 #endif
  74
  75