49 lines
940 B
JavaScript
49 lines
940 B
JavaScript
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'use strict';
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// Simple FIFO queue implementation to avoid having to do shift()
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// on an array, which is slow.
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function Queue() {
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this.length = 0;
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}
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Queue.prototype.push = function (item) {
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var node = {item: item};
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if (this.last) {
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this.last = this.last.next = node;
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} else {
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this.last = this.first = node;
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}
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this.length++;
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};
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Queue.prototype.shift = function () {
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var node = this.first;
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if (node) {
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this.first = node.next;
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if (!(--this.length)) {
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this.last = undefined;
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}
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return node.item;
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}
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};
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Queue.prototype.slice = function (start, end) {
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start = typeof start === 'undefined' ? 0 : start;
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end = typeof end === 'undefined' ? Infinity : end;
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var output = [];
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var i = 0;
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for (var node = this.first; node; node = node.next) {
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if (--end < 0) {
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break;
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} else if (++i > start) {
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output.push(node.item);
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}
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}
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return output;
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}
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module.exports = Queue;
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