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1 | // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- |
2 | // vim: ts=8 sw=2 smarttab | |
3 | /* | |
4 | * Ceph - scalable distributed file system | |
5 | * | |
6 | * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net> | |
7 | * | |
8 | * This is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License version 2.1, as published by the Free Software | |
11 | * Foundation. See file COPYING. | |
12 | * | |
13 | */ | |
14 | ||
15 | #ifndef CEPH_XLIST_H | |
16 | #define CEPH_XLIST_H | |
17 | ||
18 | #include "include/assert.h" | |
19 | #include <iterator> | |
20 | #include <cstdlib> | |
21 | ||
22 | template<typename T> | |
23 | class xlist { | |
24 | public: | |
25 | struct item { | |
26 | T _item; | |
27 | item *_prev, *_next; | |
28 | xlist *_list; | |
29 | ||
30 | item(T i) : _item(i), _prev(0), _next(0), _list(0) {} | |
31 | ~item() { | |
32 | assert(!is_on_list()); | |
33 | //remove_myself(); | |
34 | } | |
35 | ||
36 | // no copying! | |
37 | item(const item& other); | |
38 | const item& operator= (const item& right); | |
39 | ||
40 | ||
41 | xlist* get_list() { return _list; } | |
42 | bool is_on_list() const { return _list ? true:false; } | |
43 | bool remove_myself() { | |
44 | if (_list) { | |
45 | _list->remove(this); | |
46 | assert(_list == 0); | |
47 | return true; | |
48 | } else | |
49 | return false; | |
50 | } | |
51 | void move_to_front() { | |
52 | assert(_list); | |
53 | _list->push_front(this); | |
54 | } | |
55 | void move_to_back() { | |
56 | assert(_list); | |
57 | _list->push_back(this); | |
58 | } | |
59 | }; | |
60 | ||
61 | typedef item* value_type; | |
62 | typedef item* const_reference; | |
63 | ||
64 | private: | |
65 | item *_front, *_back; | |
66 | int _size; | |
67 | ||
68 | public: | |
69 | xlist(const xlist& other) { | |
70 | _front = other._front; | |
71 | _back = other._back; | |
72 | _size = other._size; | |
73 | } | |
74 | ||
75 | xlist() : _front(0), _back(0), _size(0) {} | |
76 | ~xlist() { | |
77 | assert(_size == 0); | |
78 | assert(_front == 0); | |
79 | assert(_back == 0); | |
80 | } | |
81 | ||
82 | int size() const { | |
83 | assert((bool)_front == (bool)_size); | |
84 | return _size; | |
85 | } | |
86 | bool empty() const { | |
87 | assert((bool)_front == (bool)_size); | |
88 | return _front == 0; | |
89 | } | |
90 | ||
91 | void clear() { | |
92 | while (_front) | |
93 | remove(_front); | |
94 | assert((bool)_front == (bool)_size); | |
95 | } | |
96 | ||
97 | void push_front(item *i) { | |
98 | if (i->_list) | |
99 | i->_list->remove(i); | |
100 | ||
101 | i->_list = this; | |
102 | i->_next = _front; | |
103 | i->_prev = 0; | |
104 | if (_front) | |
105 | _front->_prev = i; | |
106 | else | |
107 | _back = i; | |
108 | _front = i; | |
109 | _size++; | |
110 | } | |
111 | void push_back(item *i) { | |
112 | if (i->_list) | |
113 | i->_list->remove(i); | |
114 | ||
115 | i->_list = this; | |
116 | i->_next = 0; | |
117 | i->_prev = _back; | |
118 | if (_back) | |
119 | _back->_next = i; | |
120 | else | |
121 | _front = i; | |
122 | _back = i; | |
123 | _size++; | |
124 | } | |
125 | void remove(item *i) { | |
126 | assert(i->_list == this); | |
127 | ||
128 | if (i->_prev) | |
129 | i->_prev->_next = i->_next; | |
130 | else | |
131 | _front = i->_next; | |
132 | if (i->_next) | |
133 | i->_next->_prev = i->_prev; | |
134 | else | |
135 | _back = i->_prev; | |
136 | _size--; | |
137 | ||
138 | i->_list = 0; | |
139 | i->_next = i->_prev = 0; | |
140 | assert((bool)_front == (bool)_size); | |
141 | } | |
142 | ||
143 | T front() { return static_cast<T>(_front->_item); } | |
144 | const T front() const { return static_cast<const T>(_front->_item); } | |
145 | ||
146 | T back() { return static_cast<T>(_back->_item); } | |
147 | const T back() const { return static_cast<const T>(_back->_item); } | |
148 | ||
149 | void pop_front() { | |
150 | assert(!empty()); | |
151 | remove(_front); | |
152 | } | |
153 | void pop_back() { | |
154 | assert(!empty()); | |
155 | remove(_back); | |
156 | } | |
157 | ||
158 | class iterator: std::iterator<std::forward_iterator_tag, T> { | |
159 | private: | |
160 | item *cur; | |
161 | public: | |
162 | iterator(item *i = 0) : cur(i) {} | |
163 | T operator*() { return static_cast<T>(cur->_item); } | |
164 | iterator& operator++() { | |
165 | assert(cur); | |
166 | assert(cur->_list); | |
167 | cur = cur->_next; | |
168 | return *this; | |
169 | } | |
170 | bool end() const { return cur == 0; } | |
171 | bool operator==(const iterator& rhs) const { | |
172 | return cur == rhs.cur; | |
173 | } | |
174 | bool operator!=(const iterator& rhs) const { | |
175 | return cur != rhs.cur; | |
176 | } | |
177 | }; | |
178 | ||
179 | iterator begin() { return iterator(_front); } | |
180 | iterator end() { return iterator(NULL); } | |
181 | ||
182 | class const_iterator: std::iterator<std::forward_iterator_tag, T> { | |
183 | private: | |
184 | item *cur; | |
185 | public: | |
186 | const_iterator(item *i = 0) : cur(i) {} | |
187 | const T operator*() { return static_cast<const T>(cur->_item); } | |
188 | const_iterator& operator++() { | |
189 | assert(cur); | |
190 | assert(cur->_list); | |
191 | cur = cur->_next; | |
192 | return *this; | |
193 | } | |
194 | bool end() const { return cur == 0; } | |
195 | }; | |
196 | ||
197 | const_iterator begin() const { return const_iterator(_front); } | |
198 | const_iterator end() const { return const_iterator(NULL); } | |
199 | }; | |
200 | ||
201 | ||
202 | #endif |