ceph/src/boost/boost/poly_collection/detail/iterator_traits.hpp

   1 /* Copyright 2016-2017 Joaquin M Lopez Munoz.
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * See http://www.boost.org/libs/poly_collection for library home page.
   7  */
   8
   9 #ifndef BOOST_POLY_COLLECTION_DETAIL_ITERATOR_TRAITS_HPP
  10 #define BOOST_POLY_COLLECTION_DETAIL_ITERATOR_TRAITS_HPP
  11
  12 #if defined(_MSC_VER)
  13 #pragma once
  14 #endif
  15
  16 #include <iterator>
  17 #include <type_traits>
  18
  19 namespace boost{
  20
  21 namespace poly_collection{
  22
  23 namespace common_impl{
  24
  25 template<typename Model,typename Allocator>
  26 class poly_collection;
  27
  28 }
  29
  30 namespace detail{
  31
  32 /* (Internal) bunch of traits-grouped functions for const-preserving
  33  * interoperatibility between iterators and local iterators of a
  34  * poly_collection.
  35  */
  36
  37 template<typename Iterator>
  38 struct poly_collection_of /* to be specialized for iterator impls */
  39 {
  40  using type=void;
  41 };
  42
  43 template<typename PolyCollection>
  44 struct model_of;
  45
  46 template<typename Model,typename Allocator>
  47 struct model_of<common_impl::poly_collection<Model,Allocator>>
  48 {
  49   using type=Model;
  50 };
  51
  52 template<typename Iterator>
  53 struct iterator_traits
  54 {
  55   using container_type=typename poly_collection_of<Iterator>::type;
  56   using is_const_iterator=typename std::is_const<
  57     typename std::remove_reference<
  58       typename std::iterator_traits<Iterator>::reference
  59     >::type
  60   >::type;
  61   using iterator=typename std::conditional<
  62     is_const_iterator::value,
  63     typename container_type::const_iterator,
  64     typename container_type::iterator
  65   >::type;
  66   using base_segment_info_iterator=typename std::conditional<
  67     is_const_iterator::value,
  68     typename container_type::const_base_segment_info_iterator,
  69     typename container_type::base_segment_info_iterator
  70   >::type;
  71   using local_base_iterator=typename std::conditional<
  72     is_const_iterator::value,
  73     typename container_type::const_local_base_iterator,
  74     typename container_type::local_base_iterator
  75   >::type;
  76   template<typename T>
  77   using local_iterator=typename std::conditional<
  78     is_const_iterator::value,
  79     typename container_type::template const_local_iterator<T>,
  80     typename container_type::template local_iterator<T>
  81   >::type;
  82
  83   static base_segment_info_iterator
  84   base_segment_info_iterator_from(iterator it)noexcept{return it.mapit;}
  85
  86   static base_segment_info_iterator
  87   base_segment_info_iterator_from(local_base_iterator it)noexcept
  88     {return it.mapit;}
  89
  90   static base_segment_info_iterator
  91   end_base_segment_info_iterator_from(iterator it)noexcept{return it.mapend;}
  92
  93   static local_base_iterator
  94   local_base_iterator_from(iterator it)noexcept
  95   {
  96     return {
  97       it.mapit,
  98       model_of<container_type>::type::nonconst_iterator(it.segpos)
  99     };
 100   }
 101
 102   static iterator
 103   iterator_from(
 104     local_base_iterator lbit,base_segment_info_iterator mapend)noexcept
 105   {
 106     return {lbit.mapit,mapend.base(),lbit.base()};
 107   }
 108 };
 109
 110 } /* namespace poly_collection::detail */
 111
 112 } /* namespace poly_collection */
 113
 114 } /* namespace boost */
 115
 116 #endif