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
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(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
98template<typename Node,typename Predicate>
99bool 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
106template<typename Node,typename Predicate>
107bool 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
121