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
37namespace WTF {
38
39template <typename T>
40class LinkedStack {
41    WTF_MAKE_FAST_ALLOCATED;
42public:
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
65private:
66    OwnPtr<Node> m_head;
67    size_t m_size;
68};
69
70template <typename T>
71LinkedStack<T>::Node::Node(const T& data, PassOwnPtr<Node> next)
72    : m_data(data)
73    , m_next(next)
74{
75}
76
77template <typename T>
78inline bool LinkedStack<T>::isEmpty()
79{
80    return !m_head;
81}
82
83template <typename T>
84inline void LinkedStack<T>::push(const T& data)
85{
86    m_head = adoptPtr(new Node(data, m_head.release()));
87    ++m_size;
88}
89
90template <typename T>
91inline const T& LinkedStack<T>::peek()
92{
93    return m_head->m_data;
94}
95
96template <typename T>
97inline void LinkedStack<T>::pop()
98{
99    ASSERT(m_head && m_size);
100    m_head = m_head->m_next.release();
101    --m_size;
102}
103
104template <typename T>
105inline size_t LinkedStack<T>::size()
106{
107    return m_size;
108}
109
110}
111
112using WTF::LinkedStack;
113
114#endif
115