"use strict";
/*
Queue.js
A function to represent a queue
Created by Kate Morley - http://code.iamkate.com/ - and released under the terms
of the CC0 1.0 Universal legal code:
http://creativecommons.org/publicdomain/zero/1.0/legalcode
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.Queue = void 0;
const MAX_UNUSED_ARRAY_SIZE = 10000;
/* Creates a new queue. A queue is a first-in-first-out (FIFO) data structure -
* items are added to the end of the queue and removed from the front.
*/
class Queue {
constructor() {
// Initialize the queue and offset
this.queue = [];
this.offset = 0;
}
// Returns the length of the queue.
getLength() {
return this.queue.length - this.offset;
}
/* Enqueues the specified item. The parameter is:
*
* item - the item to enqueue
*/
enqueue(item) {
this.queue.push(item);
}
/* Dequeues an item and returns it. If the queue is empty, the value
* 'undefined' is returned.
*/
dequeue() {
// if the queue is empty, return immediately
if (this.queue.length === 0) {
return undefined;
}
// store the item at the front of the queue
const item = this.queue[this.offset];
// increment the offset and remove the free space if necessary
if (++this.offset > MAX_UNUSED_ARRAY_SIZE) {
this.queue = this.queue.slice(this.offset);
this.offset = 0;
}
// return the dequeued item
return item;
}
}
exports.Queue = Queue;
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