Andrew Zambazos
113 lines
2.8 KiB
JavaScript
113 lines
2.8 KiB
JavaScript
/*
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* Copyright (C) 2016 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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class LinkedList
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{
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constructor()
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{
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this.head = new LinkedListNode;
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this.head.next = this.head.prev = this.head;
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this.length = 0;
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}
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clear()
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{
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this.head.next = this.head.prev = this.head;
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this.length = 0;
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}
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get last()
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{
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return this.head.prev;
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}
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push(item)
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{
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let newNode = new LinkedListNode(item);
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let last = this.last;
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let head = this.head;
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last.next = newNode;
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newNode.next = head;
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head.prev = newNode;
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newNode.prev = last;
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this.length++;
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return newNode;
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}
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remove(node)
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{
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if (!node)
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return false;
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node.prev.next = node.next;
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node.next.prev = node.prev;
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this.length--;
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return true;
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}
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forEach(callback)
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{
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let node = this.head;
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for (let i = 0, length = this.length; i < length; i++) {
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node = node.next;
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let returnValue = callback(node.value, i);
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if (returnValue === false)
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return;
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}
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}
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toArray()
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{
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let node = this.head;
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let i = this.length;
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let result = new Array(i);
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while (i--) {
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node = node.prev;
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result[i] = node.value;
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}
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return result;
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}
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toJSON()
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{
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return this.toArray();
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}
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}
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class LinkedListNode
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{
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constructor(value)
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{
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this.value = value;
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this.prev = null;
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this.next = null;
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}
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}
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