33 lines
697 B
JavaScript
33 lines
697 B
JavaScript
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var ensureTwoPower = function(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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var Cyclist = function(size) {
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if (!(this instanceof Cyclist)) return new Cyclist(size);
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size = ensureTwoPower(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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