ceph/src/boost/libs/fusion/include/boost/fusion/adapted/std_tuple/std_tuple_iterator.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_STD_TUPLE_ITERATOR_09112011_1905)
   8 #define FUSION_STD_TUPLE_ITERATOR_09112011_1905
   9
  10 #include <boost/fusion/support/config.hpp>
  11 #include <boost/fusion/iterator/iterator_facade.hpp>
  12 #include <boost/type_traits/is_const.hpp>
  13 #include <boost/type_traits/remove_const.hpp>
  14 #include <boost/fusion/support/detail/access.hpp>
  15 #include <boost/mpl/int.hpp>
  16 #include <boost/mpl/if.hpp>
  17 #include <tuple>
  18 #include <utility>
  19
  20 namespace boost { namespace fusion
  21 {
  22     struct random_access_traversal_tag;
  23
  24     template <typename Tuple, int Index>
  25     struct std_tuple_iterator_identity;
  26
  27     template <typename Tuple, int Index>
  28     struct std_tuple_iterator
  29         : iterator_facade<
  30               std_tuple_iterator<Tuple, Index>
  31             , random_access_traversal_tag>
  32     {
  33         typedef Tuple tuple_type;
  34         static int const index = Index;
  35         typedef std_tuple_iterator_identity<
  36             typename add_const<Tuple>::type, Index>
  37         identity;
  38
  39         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  40         explicit std_tuple_iterator(Tuple& tuple)
  41           : tuple(tuple) {}
  42
  43         Tuple& tuple;
  44
  45         template <typename Iterator>
  46         struct value_of
  47           : std::tuple_element<Iterator::index,
  48               typename remove_const<typename Iterator::tuple_type>::type> {};
  49
  50         template <typename Iterator>
  51         struct deref
  52         {
  53             typedef typename value_of<Iterator>::type element;
  54             typedef typename
  55                 mpl::if_<
  56                     is_const<typename Iterator::tuple_type>
  57                   , typename fusion::detail::cref_result<element>::type
  58                   , typename fusion::detail::ref_result<element>::type
  59                 >::type
  60             type;
  61
  62             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  63             static type
  64             call(Iterator const& iter)
  65             {
  66                 return std::get<Index>(iter.tuple);
  67             }
  68         };
  69
  70         template <typename Iterator, typename N>
  71         struct advance
  72         {
  73             static int const index = Iterator::index;
  74             typedef typename Iterator::tuple_type tuple_type;
  75             typedef std_tuple_iterator<tuple_type, index+N::value> type;
  76
  77             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  78             static type
  79             call(Iterator const& i)
  80             {
  81                 return type(i.tuple);
  82             }
  83         };
  84
  85         template <typename Iterator>
  86         struct next : advance<Iterator, mpl::int_<1>> {};
  87
  88         template <typename Iterator>
  89         struct prior : advance<Iterator, mpl::int_<-1>> {};
  90
  91         template <typename I1, typename I2>
  92         struct equal_to
  93             : is_same<typename I1::identity, typename I2::identity> {};
  94
  95         template <typename First, typename Last>
  96         struct distance
  97         {
  98             typedef mpl::int_<Last::index-First::index> type;
  99
 100             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
 101             static type
 102             call(First const&, Last const&)
 103             {
 104                 return type();
 105             }
 106         };
 107     };
 108 }}
 109
 110 #ifdef BOOST_FUSION_WORKAROUND_FOR_LWG_2408
 111 namespace std
 112 {
 113     template <typename Tuple, int Index>
 114     struct iterator_traits< ::boost::fusion::std_tuple_iterator<Tuple, Index> >
 115     { };
 116 }
 117 #endif
 118
 119 #endif
 120
 121