68 lines
1.4 KiB
JavaScript
68 lines
1.4 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.default = Queue;
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/** @license MIT License (c) copyright 2010-2016 original author or authors */
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/** @author Brian Cavalier */
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/** @author John Hann */
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// Based on https://github.com/petkaantonov/deque
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function Queue(capPow2) {
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this._capacity = capPow2 || 32;
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this._length = 0;
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this._head = 0;
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}
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Queue.prototype.push = function (x) {
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var len = this._length;
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this._checkCapacity(len + 1);
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var i = this._head + len & this._capacity - 1;
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this[i] = x;
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this._length = len + 1;
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};
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Queue.prototype.shift = function () {
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var head = this._head;
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var x = this[head];
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this[head] = void 0;
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this._head = head + 1 & this._capacity - 1;
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this._length--;
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return x;
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};
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Queue.prototype.isEmpty = function () {
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return this._length === 0;
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};
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Queue.prototype.length = function () {
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return this._length;
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};
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Queue.prototype._checkCapacity = function (size) {
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if (this._capacity < size) {
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this._ensureCapacity(this._capacity << 1);
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}
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};
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Queue.prototype._ensureCapacity = function (capacity) {
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var oldCapacity = this._capacity;
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this._capacity = capacity;
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var last = this._head + this._length;
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if (last > oldCapacity) {
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copy(this, 0, this, oldCapacity, last & oldCapacity - 1);
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}
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};
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function copy(src, srcIndex, dst, dstIndex, len) {
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for (var j = 0; j < len; ++j) {
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dst[j + dstIndex] = src[j + srcIndex];
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src[j + srcIndex] = void 0;
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}
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} |