1 /*
2 * Copyright (C) 2013 Google 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 are
6 * met:
7 *
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 * * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #ifndef LinkedStack_h
32 #define LinkedStack_h
33
34 #include "wtf/FastAllocBase.h"
35 #include "wtf/OwnPtr.h"
36
37 namespace WTF {
38
39 template <typename T>
40 class LinkedStack {
41 WTF_MAKE_FAST_ALLOCATED;
42 public:
LinkedStack()43 LinkedStack() : m_size(0) { }
44
45 bool isEmpty();
46
47 void push(const T&);
48 const T& peek();
49 void pop();
50
51 size_t size();
52
53 // This inner class used to be private but is now public on account of a
54 // possible MSVC bug. It can be made private again if we get rid of
55 // WTF_MAKE_FAST_ALLOCATED ever.
56 class Node {
57 WTF_MAKE_FAST_ALLOCATED;
58 public:
59 Node(const T&, PassOwnPtr<Node> next);
60
61 T m_data;
62 OwnPtr<Node> m_next;
63 };
64
65 private:
66 OwnPtr<Node> m_head;
67 size_t m_size;
68 };
69
70 template <typename T>
Node(const T & data,PassOwnPtr<Node> next)71 LinkedStack<T>::Node::Node(const T& data, PassOwnPtr<Node> next)
72 : m_data(data)
73 , m_next(next)
74 {
75 }
76
77 template <typename T>
isEmpty()78 inline bool LinkedStack<T>::isEmpty()
79 {
80 return !m_head;
81 }
82
83 template <typename T>
push(const T & data)84 inline void LinkedStack<T>::push(const T& data)
85 {
86 m_head = adoptPtr(new Node(data, m_head.release()));
87 ++m_size;
88 }
89
90 template <typename T>
peek()91 inline const T& LinkedStack<T>::peek()
92 {
93 return m_head->m_data;
94 }
95
96 template <typename T>
pop()97 inline void LinkedStack<T>::pop()
98 {
99 ASSERT(m_head && m_size);
100 m_head = m_head->m_next.release();
101 --m_size;
102 }
103
104 template <typename T>
size()105 inline size_t LinkedStack<T>::size()
106 {
107 return m_size;
108 }
109
110 }
111
112 using WTF::LinkedStack;
113
114 #endif
115