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// Queue class adapted from Tim Caswell's pattern library
// http://github.com/creationix/pattern/blob/master/lib/pattern/queue.js
function Queue() {
this.tail = [];
this.head = [];
this.offset = 0;
}
Queue.prototype.shift = function () {
if (this.offset === this.head.length) {
var tmp = this.head;
tmp.length = 0;
this.head = this.tail;
this.tail = tmp;
this.offset = 0;
if (this.head.length === 0) {
return;
}
}
return this.head[this.offset++]; // sorry, JSLint
};
Queue.prototype.push = function (item) {
return this.tail.push(item);
};
Queue.prototype.forEach = function (fn, thisv) {
var array = this.head.slice(this.offset), i, il;
array.push.apply(array, this.tail);
if (thisv) {
for (i = 0, il = array.length; i < il; i += 1) {
fn.call(thisv, array[i], i, array);
}
} else {
for (i = 0, il = array.length; i < il; i += 1) {
fn(array[i], i, array);
}
}
return array;
};
Queue.prototype.getLength = function () {
return this.head.length - this.offset + this.tail.length;
};
Object.defineProperty(Queue.prototype, "length", {
get: function () {
return this.getLength();
}
});
if (typeof module !== "undefined" && module.exports) {
module.exports = Queue;
}
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