1 /*
2 * Copyright (C) 2011 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #ifndef DoublyLinkedList_h
27 #define DoublyLinkedList_h
28
29 namespace WTF {
30
31 template <typename Node> class DoublyLinkedList {
32 public:
33 DoublyLinkedList();
34
35 bool isEmpty();
36
37 Node* head();
38
39 void append(Node*);
40 void remove(Node*);
41
42 private:
43 Node* m_head;
44 Node* m_tail;
45 };
46
DoublyLinkedList()47 template <typename Node> inline DoublyLinkedList<Node>::DoublyLinkedList()
48 : m_head(0)
49 , m_tail(0)
50 {
51 }
52
isEmpty()53 template <typename Node> inline bool DoublyLinkedList<Node>::isEmpty()
54 {
55 return !m_head;
56 }
57
head()58 template <typename Node> inline Node* DoublyLinkedList<Node>::head()
59 {
60 return m_head;
61 }
62
append(Node * node)63 template <typename Node> inline void DoublyLinkedList<Node>::append(Node* node)
64 {
65 if (!m_tail) {
66 ASSERT(!m_head);
67 m_head = node;
68 m_tail = node;
69 node->setPrev(0);
70 node->setNext(0);
71 return;
72 }
73
74 ASSERT(m_head);
75 m_tail->setNext(node);
76 node->setPrev(m_tail);
77 node->setNext(0);
78 m_tail = node;
79 }
80
remove(Node * node)81 template <typename Node> inline void DoublyLinkedList<Node>::remove(Node* node)
82 {
83 if (node->prev()) {
84 ASSERT(node != m_head);
85 node->prev()->setNext(node->next());
86 } else {
87 ASSERT(node == m_head);
88 m_head = node->next();
89 }
90
91 if (node->next()) {
92 ASSERT(node != m_tail);
93 node->next()->setPrev(node->prev());
94 } else {
95 ASSERT(node == m_tail);
96 m_tail = node->prev();
97 }
98 }
99
100 } // namespace WTF
101
102 using WTF::DoublyLinkedList;
103
104 #endif
105