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"use strict";
function arrayMove(src, srcIndex, dst, dstIndex, len) {
for (var j = 0; j < len; ++j) {
dst[j + dstIndex] = src[j + srcIndex];
src[j + srcIndex] = void 0;
}
}
function Queue(capacity) {
this._capacity = capacity;
this._length = 0;
this._front = 0;
}
Queue.prototype._willBeOverCapacity = function (size) {
return this._capacity < size;
};
Queue.prototype._pushOne = function (arg) {
var length = this.length();
this._checkCapacity(length + 1);
var i = (this._front + length) & (this._capacity - 1);
this[i] = arg;
this._length = length + 1;
};
Queue.prototype._unshiftOne = function(value) {
var capacity = this._capacity;
this._checkCapacity(this.length() + 1);
var front = this._front;
var i = (((( front - 1 ) &
( capacity - 1) ) ^ capacity ) - capacity );
this[i] = value;
this._front = i;
this._length = this.length() + 1;
};
Queue.prototype.unshift = function(fn, receiver, arg) {
this._unshiftOne(arg);
this._unshiftOne(receiver);
this._unshiftOne(fn);
};
Queue.prototype.push = function (fn, receiver, arg) {
var length = this.length() + 3;
if (this._willBeOverCapacity(length)) {
this._pushOne(fn);
this._pushOne(receiver);
this._pushOne(arg);
return;
}
var j = this._front + length - 3;
this._checkCapacity(length);
var wrapMask = this._capacity - 1;
this[(j + 0) & wrapMask] = fn;
this[(j + 1) & wrapMask] = receiver;
this[(j + 2) & wrapMask] = arg;
this._length = length;
};
Queue.prototype.shift = function () {
var front = this._front,
ret = this[front];
this[front] = undefined;
this._front = (front + 1) & (this._capacity - 1);
this._length--;
return ret;
};
Queue.prototype.length = function () {
return this._length;
};
Queue.prototype._checkCapacity = function (size) {
if (this._capacity < size) {
this._resizeTo(this._capacity << 1);
}
};
Queue.prototype._resizeTo = function (capacity) {
var oldCapacity = this._capacity;
this._capacity = capacity;
var front = this._front;
var length = this._length;
var moveItemsCount = (front + length) & (oldCapacity - 1);
arrayMove(this, 0, this, oldCapacity, moveItemsCount);
};
module.exports = Queue;
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