ceph/src/boost/boost/poly_collection/detail/iterator_impl.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_IMPL_HPP
  10 #define BOOST_POLY_COLLECTION_DETAIL_ITERATOR_IMPL_HPP
  11
  12 #if defined(_MSC_VER)
  13 #pragma once
  14 #endif
  15
  16 #include <boost/iterator/iterator_adaptor.hpp>
  17 #include <boost/iterator/iterator_facade.hpp>
  18 #include <boost/poly_collection/detail/is_constructible.hpp>
  19 #include <boost/poly_collection/detail/iterator_traits.hpp>
  20 #include <type_traits>
  21 #include <typeinfo>
  22
  23 namespace boost{
  24
  25 namespace poly_collection{
  26
  27 namespace detail{
  28
  29 /* Implementations of poly_collection::[const_][local_[base_]]iterator moved
  30  * out of class to allow for use in deduced contexts.
  31  */
  32
  33 template<typename PolyCollection,bool Const>
  34 using iterator_impl_value_type=typename std::conditional<
  35   Const,
  36   const typename PolyCollection::value_type,
  37   typename PolyCollection::value_type
  38 >::type;
  39
  40 template<typename PolyCollection,bool Const>
  41 class iterator_impl:
  42   public boost::iterator_facade<
  43     iterator_impl<PolyCollection,Const>,
  44     iterator_impl_value_type<PolyCollection,Const>,
  45     boost::forward_traversal_tag
  46   >
  47 {
  48   using segment_type=typename PolyCollection::segment_type;
  49   using const_segment_base_iterator=
  50     typename PolyCollection::const_segment_base_iterator;
  51   using const_segment_base_sentinel=
  52     typename PolyCollection::const_segment_base_sentinel;
  53   using const_segment_map_iterator=
  54     typename PolyCollection::const_segment_map_iterator;
  55
  56 public:
  57   using value_type=iterator_impl_value_type<PolyCollection,Const>;
  58
  59 private:
  60   iterator_impl(
  61     const_segment_map_iterator mapit,
  62     const_segment_map_iterator mapend)noexcept:
  63     mapit{mapit},mapend{mapend}
  64   {
  65     next_segment_position();
  66   }
  67
  68   iterator_impl(
  69     const_segment_map_iterator mapit_,const_segment_map_iterator mapend_,
  70     const_segment_base_iterator segpos_)noexcept:
  71     mapit{mapit_},mapend{mapend_},segpos{segpos_}
  72   {
  73     if(mapit!=mapend&&segpos==sentinel()){
  74       ++mapit;
  75       next_segment_position();
  76     }
  77   }
  78
  79 public:
  80   iterator_impl()=default;
  81   iterator_impl(const iterator_impl&)=default;
  82   iterator_impl& operator=(const iterator_impl&)=default;
  83
  84   template<bool Const2,typename std::enable_if<!Const2>::type* =nullptr>
  85   iterator_impl(const iterator_impl<PolyCollection,Const2>& x):
  86     mapit{x.mapit},mapend{x.mapend},segpos{x.segpos}{}
  87
  88 private:
  89   template<typename,bool>
  90   friend class iterator_impl;
  91   friend PolyCollection;
  92   friend class boost::iterator_core_access;
  93   template<typename>
  94   friend struct iterator_traits;
  95
  96   value_type& dereference()const noexcept
  97     {return const_cast<value_type&>(*segpos);}
  98   bool equal(const iterator_impl& x)const noexcept{return segpos==x.segpos;}
  99
 100   void increment()noexcept
 101   {
 102     if(++segpos==sentinel()){
 103       ++mapit;
 104       next_segment_position();
 105     }
 106   }
 107
 108   void next_segment_position()noexcept
 109   {
 110     for(;mapit!=mapend;++mapit){
 111       segpos=segment().begin();
 112       if(segpos!=sentinel())return;
 113     }
 114     segpos=nullptr;
 115   }
 116
 117   segment_type&       segment()noexcept
 118     {return const_cast<segment_type&>(mapit->second);}
 119   const segment_type& segment()const noexcept{return mapit->second;}
 120
 121   const_segment_base_sentinel sentinel()const noexcept
 122     {return segment().sentinel();}
 123
 124   const_segment_map_iterator  mapit,mapend;
 125   const_segment_base_iterator segpos;
 126 };
 127
 128 template<typename PolyCollection,bool Const>
 129 struct poly_collection_of<iterator_impl<PolyCollection,Const>>
 130 {
 131   using type=PolyCollection;
 132 };
 133
 134 template<typename PolyCollection,typename BaseIterator>
 135 class local_iterator_impl:
 136   public boost::iterator_adaptor<
 137     local_iterator_impl<PolyCollection,BaseIterator>,
 138     BaseIterator
 139   >
 140 {
 141   using segment_type=typename PolyCollection::segment_type;
 142   using segment_base_iterator=typename PolyCollection::segment_base_iterator;
 143   using const_segment_map_iterator=
 144     typename PolyCollection::const_segment_map_iterator;
 145
 146   template<typename Iterator>
 147   local_iterator_impl(
 148     const_segment_map_iterator mapit,
 149     Iterator it):
 150     local_iterator_impl::iterator_adaptor_{BaseIterator(it)},
 151     mapit{mapit}
 152   {}
 153
 154 public:
 155   using base_iterator=BaseIterator;
 156
 157   local_iterator_impl()=default;
 158   local_iterator_impl(const local_iterator_impl&)=default;
 159   local_iterator_impl& operator=(const local_iterator_impl&)=default;
 160
 161   template<
 162     typename BaseIterator2,
 163     typename std::enable_if<
 164       std::is_convertible<BaseIterator2,BaseIterator>::value
 165     >::type* =nullptr
 166   >
 167   local_iterator_impl(
 168     const local_iterator_impl<PolyCollection,BaseIterator2>& x):
 169     local_iterator_impl::iterator_adaptor_{x.base()},
 170     mapit{x.mapit}{}
 171
 172   template<
 173     typename BaseIterator2,
 174     typename std::enable_if<
 175       !std::is_convertible<BaseIterator2,BaseIterator>::value&&
 176       is_constructible<BaseIterator,BaseIterator2>::value
 177     >::type* =nullptr
 178   >
 179   explicit local_iterator_impl(
 180     const local_iterator_impl<PolyCollection,BaseIterator2>& x):
 181     local_iterator_impl::iterator_adaptor_{BaseIterator(x.base())},
 182     mapit{x.mapit}{}
 183
 184   template<
 185     typename BaseIterator2,
 186     typename std::enable_if<
 187       !is_constructible<BaseIterator,BaseIterator2>::value&&
 188       is_constructible<BaseIterator,segment_base_iterator>::value&&
 189       is_constructible<BaseIterator2,segment_base_iterator>::value
 190     >::type* =nullptr
 191   >
 192   explicit local_iterator_impl(
 193     const local_iterator_impl<PolyCollection,BaseIterator2>& x):
 194     local_iterator_impl::iterator_adaptor_{
 195       base_iterator_from(x.segment(),x.base())},
 196     mapit{x.mapit}{}
 197
 198   /* define [] to avoid Boost.Iterator operator_brackets_proxy mess */
 199
 200   template<typename DifferenceType>
 201   typename std::iterator_traits<BaseIterator>::reference
 202   operator[](DifferenceType n)const{return *(*this+n);}
 203
 204 private:
 205   template<typename,typename>
 206   friend class local_iterator_impl;
 207   friend PolyCollection;
 208   template<typename>
 209   friend struct iterator_traits;
 210
 211   template<typename BaseIterator2>
 212   static BaseIterator base_iterator_from(
 213     const segment_type& s,BaseIterator2 it)
 214   {
 215     segment_base_iterator bit=s.begin();
 216     return BaseIterator{bit+(it-static_cast<BaseIterator2>(bit))};
 217   }
 218
 219   base_iterator              base()const noexcept
 220     {return local_iterator_impl::iterator_adaptor_::base();}
 221   const std::type_info&      type_info()const{return *mapit->first;}
 222   segment_type&              segment()noexcept
 223     {return const_cast<segment_type&>(mapit->second);}
 224   const segment_type&        segment()const noexcept{return mapit->second;}
 225
 226   const_segment_map_iterator mapit;
 227 };
 228
 229 template<typename PolyCollection,typename BaseIterator>
 230 struct poly_collection_of<local_iterator_impl<PolyCollection,BaseIterator>>
 231 {
 232   using type=PolyCollection;
 233 };
 234
 235
 236 } /* namespace poly_collection::detail */
 237
 238 } /* namespace poly_collection */
 239
 240 } /* namespace boost */
 241
 242 #endif