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/**
* Copyright (c) 2014 Petka Antonov
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:</p>
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
*/
"use strict";
var ASSERT = require("./assert.js");
function arrayCopy(src, srcIndex, dst, dstIndex, len) {
for (var j = 0; j < len; ++j) {
dst[j + dstIndex] = src[j + srcIndex];
}
}
function pow2AtLeast(n) {
n = n >>> 0;
n = n - 1;
n = n | (n >> 1);
n = n | (n >> 2);
n = n | (n >> 4);
n = n | (n >> 8);
n = n | (n >> 16);
return n + 1;
}
function getCapacity(capacity) {
if (typeof capacity !== "number") return 16;
return pow2AtLeast(
Math.min(
Math.max(16, capacity), 1073741824)
);
}
function Queue(capacity) {
this._capacity = getCapacity(capacity);
this._length = 0;
this._front = 0;
this._makeCapacity();
}
Queue.prototype._willBeOverCapacity =
function Queue$_willBeOverCapacity(size) {
return this._capacity < size;
};
Queue.prototype._pushOne = function Queue$_pushOne(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.push = function Queue$push(fn, receiver, arg) {
var length = this.length() + 3;
if (this._willBeOverCapacity(length)) {
this._pushOne(fn);
this._pushOne(receiver);
this._pushOne(arg);
return;
}
var j = this._front + length - 3;
this._checkCapacity(length);
var wrapMask = this._capacity - 1;
this[(j + 0) & wrapMask] = fn;
this[(j + 1) & wrapMask] = receiver;
this[(j + 2) & wrapMask] = arg;
this._length = length;
};
Queue.prototype.shift = function Queue$shift() {
var front = this._front,
ret = this[front];
this[front] = void 0;
this._front = (front + 1) & (this._capacity - 1);
this._length--;
return ret;
};
Queue.prototype.length = function Queue$length() {
return this._length;
};
Queue.prototype._makeCapacity = function Queue$_makeCapacity() {
var len = this._capacity;
for (var i = 0; i < len; ++i) {
this[i] = void 0;
}
};
Queue.prototype._checkCapacity = function Queue$_checkCapacity(size) {
if (this._capacity < size) {
this._resizeTo(this._capacity << 3);
}
};
Queue.prototype._resizeTo = function Queue$_resizeTo(capacity) {
var oldFront = this._front;
var oldCapacity = this._capacity;
var oldQueue = new Array(oldCapacity);
var length = this.length();
arrayCopy(this, 0, oldQueue, 0, oldCapacity);
this._capacity = capacity;
this._makeCapacity();
this._front = 0;
if (oldFront + length <= oldCapacity) {
arrayCopy(oldQueue, oldFront, this, 0, length);
}
else { var lengthBeforeWrapping =
length - ((oldFront + length) & (oldCapacity - 1));
arrayCopy(oldQueue, oldFront, this, 0, lengthBeforeWrapping);
arrayCopy(oldQueue, 0, this, lengthBeforeWrapping,
length - lengthBeforeWrapping);
}
};
module.exports = Queue;
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