74 lines
1.8 KiB
JavaScript
74 lines
1.8 KiB
JavaScript
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"use strict";
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function arrayMove(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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}
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function Queue(capacity) {
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this._capacity = capacity;
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this._length = 0;
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this._front = 0;
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}
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Queue.prototype._willBeOverCapacity = function (size) {
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return this._capacity < size;
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};
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Queue.prototype._pushOne = function (arg) {
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var length = this.length();
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this._checkCapacity(length + 1);
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var i = (this._front + length) & (this._capacity - 1);
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this[i] = arg;
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this._length = length + 1;
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};
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Queue.prototype.push = function (fn, receiver, arg) {
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var length = this.length() + 3;
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if (this._willBeOverCapacity(length)) {
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this._pushOne(fn);
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this._pushOne(receiver);
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this._pushOne(arg);
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return;
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}
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var j = this._front + length - 3;
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this._checkCapacity(length);
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var wrapMask = this._capacity - 1;
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this[(j + 0) & wrapMask] = fn;
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this[(j + 1) & wrapMask] = receiver;
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this[(j + 2) & wrapMask] = arg;
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this._length = length;
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};
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Queue.prototype.shift = function () {
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var front = this._front,
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ret = this[front];
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this[front] = undefined;
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this._front = (front + 1) & (this._capacity - 1);
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this._length--;
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return ret;
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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._resizeTo(this._capacity << 1);
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}
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};
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Queue.prototype._resizeTo = function (capacity) {
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var oldCapacity = this._capacity;
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this._capacity = capacity;
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var front = this._front;
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var length = this._length;
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var moveItemsCount = (front + length) & (oldCapacity - 1);
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arrayMove(this, 0, this, oldCapacity, moveItemsCount);
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};
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module.exports = Queue;
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