source: NonGTP/Boost/boost/multi_index/detail/duplicates_iterator.hpp @ 857

Revision 857, 2.7 KB checked in by igarcia, 19 years ago (diff)
Line 
1/* Copyright 2003-2005 Joaquín M López Muñoz.
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)&&(_MSC_VER>=1200)
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
20namespace boost{
21
22namespace multi_index{
23
24namespace detail{
25
26/* duplicates_operator is given a range of ordered elements and
27 * passes only over those which are duplicated.
28 */
29
30template<typename Node,typename Predicate>
31class duplicates_iterator
32{
33public:
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
77private:
78  void sync()
79  {
80    if(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      node=node2;
89    }
90    begin_chunk=node;
91  }
92
93  Node*     node;
94  Node*     begin_chunk;
95  Node*     end;
96  Predicate pred;
97};
98
99template<typename Node,typename Predicate>
100bool operator==(
101  const duplicates_iterator<Node,Predicate>& x,
102  const duplicates_iterator<Node,Predicate>& y)
103{
104  return x.get_node()==y.get_node();
105}
106
107template<typename Node,typename Predicate>
108bool operator!=(
109  const duplicates_iterator<Node,Predicate>& x,
110  const duplicates_iterator<Node,Predicate>& y)
111{
112  return !(x==y);
113}
114
115} /* namespace multi_index::detail */
116
117} /* namespace multi_index */
118
119} /* namespace boost */
120
121#endif
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