1 /* Copyright 2003-2018 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 <iterator>
18
19 namespace boost{
20
21 namespace multi_index{
22
23 namespace detail{
24
25 /* duplicates_operator is given a range of ordered elements and
26 * passes only over those which are duplicated.
27 */
28
29 template<typename Node,typename Predicate>
30 class duplicates_iterator
31 {
32 public:
33 typedef typename Node::value_type value_type;
34 typedef typename Node::difference_type difference_type;
35 typedef const typename Node::value_type* pointer;
36 typedef const typename Node::value_type& reference;
37 typedef std::forward_iterator_tag iterator_category;
38
duplicates_iterator(Node * node_,Node * end_,Predicate pred_)39 duplicates_iterator(Node* node_,Node* end_,Predicate pred_):
40 node(node_),begin_chunk(0),end(end_),pred(pred_)
41 {
42 advance();
43 }
44
duplicates_iterator(Node * end_,Predicate pred_)45 duplicates_iterator(Node* end_,Predicate pred_):
46 node(end_),begin_chunk(end_),end(end_),pred(pred_)
47 {
48 }
49
operator *() const50 reference operator*()const
51 {
52 return node->value();
53 }
54
operator ->() const55 pointer operator->()const
56 {
57 return &node->value();
58 }
59
operator ++()60 duplicates_iterator& operator++()
61 {
62 Node::increment(node);
63 sync();
64 return *this;
65 }
66
operator ++(int)67 duplicates_iterator operator++(int)
68 {
69 duplicates_iterator tmp(*this);
70 ++(*this);
71 return tmp;
72 }
73
get_node() const74 Node* get_node()const{return node;}
75
76 private:
sync()77 void sync()
78 {
79 if(node!=end&&pred(begin_chunk->value(),node->value()))advance();
80 }
81
advance()82 void advance()
83 {
84 for(Node* node2=node;node!=end;node=node2){
85 Node::increment(node2);
86 if(node2!=end&&!pred(node->value(),node2->value()))break;
87 }
88 begin_chunk=node;
89 }
90
91 Node* node;
92 Node* begin_chunk;
93 Node* end;
94 Predicate pred;
95 };
96
97 template<typename Node,typename Predicate>
operator ==(const duplicates_iterator<Node,Predicate> & x,const duplicates_iterator<Node,Predicate> & y)98 bool operator==(
99 const duplicates_iterator<Node,Predicate>& x,
100 const duplicates_iterator<Node,Predicate>& y)
101 {
102 return x.get_node()==y.get_node();
103 }
104
105 template<typename Node,typename Predicate>
operator !=(const duplicates_iterator<Node,Predicate> & x,const duplicates_iterator<Node,Predicate> & y)106 bool operator!=(
107 const duplicates_iterator<Node,Predicate>& x,
108 const duplicates_iterator<Node,Predicate>& y)
109 {
110 return !(x==y);
111 }
112
113 } /* namespace multi_index::detail */
114
115 } /* namespace multi_index */
116
117 } /* namespace boost */
118
119 #endif
120