ceph/src/boost/libs/fusion/include/boost/fusion/view/repetitive_view/detail/next_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2007 Tobias Schwinger
   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
   8 #if !defined(BOOST_FUSION_REPETITIVE_VIEW_NEXT_IMPL_HPP_INCLUDED)
   9 #define BOOST_FUSION_REPETITIVE_VIEW_NEXT_IMPL_HPP_INCLUDED
  10
  11 #include <boost/fusion/support/config.hpp>
  12 #include <boost/fusion/iterator/next.hpp>
  13 #include <boost/fusion/iterator/equal_to.hpp>
  14
  15 namespace boost { namespace fusion
  16 {
  17     struct repetitive_view_iterator_tag;
  18
  19     template <typename Sequence, typename Pos>
  20     struct repetitive_view_iterator;
  21
  22     namespace extension
  23     {
  24         template <typename Tag>
  25         struct next_impl;
  26
  27         template <>
  28         struct next_impl<repetitive_view_iterator_tag>
  29         {
  30             template<typename Iterator,
  31                 bool Last = result_of::equal_to<typename Iterator::end_type,
  32                     typename result_of::next<
  33                         typename Iterator::pos_type
  34                     >::type>::value >
  35             struct apply_nonempty // <Iterator,false>
  36             {
  37                 // advanvce to next position
  38
  39                 typedef repetitive_view_iterator<
  40                     typename Iterator::sequence_type,
  41                     typename result_of::next<typename Iterator::pos_type>::type
  42                     >
  43                 type;
  44
  45                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  46                 static type call(Iterator const& i)
  47                 {
  48                     return type(i.seq, next(i.pos));
  49                 }
  50             };
  51             template <typename Iterator>
  52             struct apply_nonempty<Iterator,true>
  53             {
  54                 // reset to beginning
  55
  56                 typedef repetitive_view_iterator<
  57                     typename Iterator::sequence_type,
  58                     typename Iterator::first_type
  59                     >
  60                 type;
  61
  62                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  63                 static type call(Iterator const& i)
  64                 {
  65                     return type(i.seq);
  66                 }
  67             };
  68
  69             template <typename Iterator,
  70                 bool Empty = result_of::equal_to<typename Iterator::end_type,
  71                     typename Iterator::pos_type>::value >
  72             struct apply // <Iterator,false>
  73                 : apply_nonempty<Iterator>
  74             { };
  75
  76             template <typename Iterator>
  77             struct apply<Iterator,true>
  78             {
  79                 // eps^n = eps
  80
  81                 typedef Iterator type;
  82
  83                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  84                 static type call(Iterator const& i)
  85                 {
  86                     return type(i);
  87                 }
  88             };
  89         };
  90     }
  91 }}
  92
  93 #endif
  94