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/*
* Copyright (C) 2013 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef LinkedStack_h
#define LinkedStack_h
#include "wtf/Allocator.h"
#include "wtf/PtrUtil.h"
#include <memory>
namespace WTF {
template <typename T>
class LinkedStack {
USING_FAST_MALLOC(LinkedStack);
public:
LinkedStack() : m_size(0) {}
// Iterative cleanup to prevent stack overflow problems.
~LinkedStack() {
std::unique_ptr<Node> ptr = m_head.release();
while (ptr)
ptr = ptr->m_next.release();
}
bool isEmpty();
void push(const T&);
const T& peek();
void pop();
size_t size();
private:
class Node {
USING_FAST_MALLOC(LinkedStack::Node);
public:
Node(const T&, std::unique_ptr<Node> next);
T m_data;
std::unique_ptr<Node> m_next;
};
std::unique_ptr<Node> m_head;
size_t m_size;
};
template <typename T>
LinkedStack<T>::Node::Node(const T& data, std::unique_ptr<Node> next)
: m_data(data), m_next(next) {}
template <typename T>
inline bool LinkedStack<T>::isEmpty() {
return !m_head;
}
template <typename T>
inline void LinkedStack<T>::push(const T& data) {
m_head = WTF::wrapUnique(new Node(data, m_head.release()));
++m_size;
}
template <typename T>
inline const T& LinkedStack<T>::peek() {
return m_head->m_data;
}
template <typename T>
inline void LinkedStack<T>::pop() {
DCHECK(m_head);
DCHECK(m_size);
m_head = m_head->m_next.release();
--m_size;
}
template <typename T>
inline size_t LinkedStack<T>::size() {
return m_size;
}
} // namespace WTF
using WTF::LinkedStack;
#endif
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