deps/boost_1_63_0/boost/multi_index/detail/duplicates_iterator.hpp

   1 /* Copyright 2003-2013 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/multi_index for library home page.
   7  */
   8
   9 #ifndef BOOST_MULTI_INDEX_DETAIL_DUPLICATES_ITERATOR_HPP
  10 #define BOOST_MULTI_INDEX_DETAIL_DUPLICATES_ITERATOR_HPP
  11
  12 #if defined(_MSC_VER)
  13 #pragma once
  14 #endif
  15
  16 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
  17 #include <cstddef>
  18 #include <iterator>
  19
  20 namespace boost{
  21
  22 namespace multi_index{
  23
  24 namespace detail{
  25
  26 /* duplicates_operator is given a range of ordered elements and
  27  * passes only over those which are duplicated.
  28  */
  29
  30 template<typename Node,typename Predicate>
  31 class duplicates_iterator
  32 {
  33 public:
  34   typedef typename Node::value_type        value_type;
  35   typedef std::ptrdiff_t                   difference_type;
  36   typedef const typename Node::value_type* pointer;
  37   typedef const typename Node::value_type& reference;
  38   typedef std::forward_iterator_tag        iterator_category;
  39
  40   duplicates_iterator(Node* node_,Node* end_,Predicate pred_):
  41     node(node_),begin_chunk(0),end(end_),pred(pred_)
  42   {
  43     advance();
  44   }
  45
  46   duplicates_iterator(Node* end_,Predicate pred_):
  47     node(end_),begin_chunk(end_),end(end_),pred(pred_)
  48   {
  49   }
  50
  51   reference operator*()const
  52   {
  53     return node->value();
  54   }
  55
  56   pointer operator->()const
  57   {
  58     return &node->value();
  59   }
  60
  61   duplicates_iterator& operator++()
  62   {
  63     Node::increment(node);
  64     sync();
  65     return *this;
  66   }
  67
  68   duplicates_iterator operator++(int)
  69   {
  70     duplicates_iterator tmp(*this);
  71     ++(*this);
  72     return tmp;
  73   }
  74
  75   Node* get_node()const{return node;}
  76
  77 private:
  78   void sync()
  79   {
  80     if(node!=end&&pred(begin_chunk->value(),node->value()))advance();
  81   }
  82
  83   void advance()
  84   {
  85     for(Node* node2=node;node!=end;node=node2){
  86       Node::increment(node2);
  87       if(node2!=end&&!pred(node->value(),node2->value()))break;
  88     }
  89     begin_chunk=node;
  90   }
  91
  92   Node*     node;
  93   Node*     begin_chunk;
  94   Node*     end;
  95   Predicate pred;
  96 };
  97
  98 template<typename Node,typename Predicate>
  99 bool operator==(
 100   const duplicates_iterator<Node,Predicate>& x,
 101   const duplicates_iterator<Node,Predicate>& y)
 102 {
 103   return x.get_node()==y.get_node();
 104 }
 105
 106 template<typename Node,typename Predicate>
 107 bool operator!=(
 108   const duplicates_iterator<Node,Predicate>& x,
 109   const duplicates_iterator<Node,Predicate>& y)
 110 {
 111   return !(x==y);
 112 }
 113
 114 } /* namespace multi_index::detail */
 115
 116 } /* namespace multi_index */
 117
 118 } /* namespace boost */
 119
 120 #endif