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73 lines
1.8 KiB
73 lines
1.8 KiB
"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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