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Diffstat (limited to 'Source/JavaScriptCore/wtf/SentinelLinkedList.h')
-rw-r--r-- | Source/JavaScriptCore/wtf/SentinelLinkedList.h | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/wtf/SentinelLinkedList.h b/Source/JavaScriptCore/wtf/SentinelLinkedList.h new file mode 100644 index 0000000..610d2d2 --- /dev/null +++ b/Source/JavaScriptCore/wtf/SentinelLinkedList.h @@ -0,0 +1,109 @@ +/* + * 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 + |