2a09d1a4
 liuqimichale
添加宜春 天水 宣化
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var ensureTwoPower = function(n) {
if (n && !(n & (n - 1))) return n;
var p = 1;
while (p < n) p <<= 1;
return p;
};
var Cyclist = function(size) {
if (!(this instanceof Cyclist)) return new Cyclist(size);
size = ensureTwoPower(size);
this.mask = size-1;
this.size = size;
this.values = new Array(size);
};
Cyclist.prototype.put = function(index, val) {
var pos = index & this.mask;
this.values[pos] = val;
return pos;
};
Cyclist.prototype.get = function(index) {
return this.values[index & this.mask];
};
Cyclist.prototype.del = function(index) {
var pos = index & this.mask;
var val = this.values[pos];
this.values[pos] = undefined;
return val;
};
module.exports = Cyclist;
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