| /* |
| * 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. |
| */ |
| |
| // A SentinelLinkedList is a linked list with dummy head and tail sentinels, |
| // which allow for branch-less insertion and removal, and removal without a |
| // pointer to the list. |
| // |
| // Requires: Node is a concrete class with: |
| // Node(SentinelTag); |
| // void setPrev(Node*); |
| // Node* prev(); |
| // void setNext(Node*); |
| // Node* next(); |
| |
| #ifndef SentinelLinkedList_h |
| #define SentinelLinkedList_h |
| |
| namespace WTF { |
| |
| enum SentinelTag { Sentinel }; |
| |
| template <typename Node> class SentinelLinkedList { |
| public: |
| typedef Node* iterator; |
| |
| SentinelLinkedList(); |
| |
| void push(Node*); |
| static void remove(Node*); |
| |
| iterator begin(); |
| iterator end(); |
| |
| private: |
| Node m_headSentinel; |
| Node m_tailSentinel; |
| }; |
| |
| template <typename Node> inline SentinelLinkedList<Node>::SentinelLinkedList() |
| : m_headSentinel(Sentinel) |
| , m_tailSentinel(Sentinel) |
| { |
| m_headSentinel.setNext(&m_tailSentinel); |
| m_headSentinel.setPrev(0); |
| |
| m_tailSentinel.setPrev(&m_headSentinel); |
| m_tailSentinel.setNext(0); |
| } |
| |
| template <typename Node> inline typename SentinelLinkedList<Node>::iterator SentinelLinkedList<Node>::begin() |
| { |
| return m_headSentinel.next(); |
| } |
| |
| template <typename Node> inline typename SentinelLinkedList<Node>::iterator SentinelLinkedList<Node>::end() |
| { |
| return &m_tailSentinel; |
| } |
| |
| template <typename Node> inline void SentinelLinkedList<Node>::push(Node* node) |
| { |
| ASSERT(node); |
| Node* prev = &m_headSentinel; |
| Node* next = m_headSentinel.next(); |
| |
| node->setPrev(prev); |
| node->setNext(next); |
| |
| prev->setNext(node); |
| next->setPrev(node); |
| } |
| |
| template <typename Node> inline void SentinelLinkedList<Node>::remove(Node* node) |
| { |
| Node* prev = node->prev(); |
| Node* next = node->next(); |
| |
| prev->setNext(next); |
| next->setPrev(prev); |
| } |
| |
| } |
| |
| using WTF::SentinelLinkedList; |
| |
| #endif |
| |