forked from zhurui/management
36 lines
700 B
JavaScript
36 lines
700 B
JavaScript
/* eslint-disable no-var */
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function Cyclist (size) {
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if (!(this instanceof Cyclist)) return new Cyclist(size)
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size = twoify(size)
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this.mask = size - 1
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this.size = size
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this.values = new Array(size)
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}
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Cyclist.prototype.put = function (index, val) {
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var pos = index & this.mask
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this.values[pos] = val
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return pos
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}
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Cyclist.prototype.get = function (index) {
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return this.values[index & this.mask]
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}
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Cyclist.prototype.del = function (index) {
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var pos = index & this.mask
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var val = this.values[pos]
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this.values[pos] = undefined
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return val
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}
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module.exports = Cyclist
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function twoify (n) {
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if (n && !(n & (n - 1))) return n
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var p = 1
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while (p < n) p <<= 1
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return p
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}
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