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/*
* Copyright (C) 2011 Apple 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:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 SKY_ENGINE_WTF_DOUBLYLINKEDLIST_H_
#define SKY_ENGINE_WTF_DOUBLYLINKEDLIST_H_
namespace WTF {
// This class allows nodes to share code without dictating data member layout.
template<typename T> class DoublyLinkedListNode {
public:
DoublyLinkedListNode();
void setPrev(T*);
void setNext(T*);
T* prev() const;
T* next() const;
};
template<typename T> inline DoublyLinkedListNode<T>::DoublyLinkedListNode()
{
setPrev(0);
setNext(0);
}
template<typename T> inline void DoublyLinkedListNode<T>::setPrev(T* prev)
{
static_cast<T*>(this)->m_prev = prev;
}
template<typename T> inline void DoublyLinkedListNode<T>::setNext(T* next)
{
static_cast<T*>(this)->m_next = next;
}
template<typename T> inline T* DoublyLinkedListNode<T>::prev() const
{
return static_cast<const T*>(this)->m_prev;
}
template<typename T> inline T* DoublyLinkedListNode<T>::next() const
{
return static_cast<const T*>(this)->m_next;
}
template<typename T> class DoublyLinkedList {
public:
DoublyLinkedList();
bool isEmpty() const;
size_t size() const; // This is O(n).
void clear();
T* head() const;
T* removeHead();
T* tail() const;
void push(T*);
void append(T*);
void remove(T*);
private:
T* m_head;
T* m_tail;
};
template<typename T> inline DoublyLinkedList<T>::DoublyLinkedList()
: m_head(0)
, m_tail(0)
{
}
template<typename T> inline bool DoublyLinkedList<T>::isEmpty() const
{
return !m_head;
}
template<typename T> inline size_t DoublyLinkedList<T>::size() const
{
size_t size = 0;
for (T* node = m_head; node; node = node->next())
++size;
return size;
}
template<typename T> inline void DoublyLinkedList<T>::clear()
{
m_head = 0;
m_tail = 0;
}
template<typename T> inline T* DoublyLinkedList<T>::head() const
{
return m_head;
}
template<typename T> inline T* DoublyLinkedList<T>::tail() const
{
return m_tail;
}
template<typename T> inline void DoublyLinkedList<T>::push(T* node)
{
if (!m_head) {
ASSERT(!m_tail);
m_head = node;
m_tail = node;
node->setPrev(0);
node->setNext(0);
return;
}
ASSERT(m_tail);
m_head->setPrev(node);
node->setNext(m_head);
node->setPrev(0);
m_head = node;
}
template<typename T> inline void DoublyLinkedList<T>::append(T* node)
{
if (!m_tail) {
ASSERT(!m_head);
m_head = node;
m_tail = node;
node->setPrev(0);
node->setNext(0);
return;
}
ASSERT(m_head);
m_tail->setNext(node);
node->setPrev(m_tail);
node->setNext(0);
m_tail = node;
}
template<typename T> inline void DoublyLinkedList<T>::remove(T* node)
{
if (node->prev()) {
ASSERT(node != m_head);
node->prev()->setNext(node->next());
} else {
ASSERT(node == m_head);
m_head = node->next();
}
if (node->next()) {
ASSERT(node != m_tail);
node->next()->setPrev(node->prev());
} else {
ASSERT(node == m_tail);
m_tail = node->prev();
}
}
template<typename T> inline T* DoublyLinkedList<T>::removeHead()
{
T* node = head();
if (node)
remove(node);
return node;
}
} // namespace WTF
using WTF::DoublyLinkedListNode;
using WTF::DoublyLinkedList;
#endif // SKY_ENGINE_WTF_DOUBLYLINKEDLIST_H_