收藏一个Hash算法

var rand = (function() {
    var seed = 49734321;
    return function() {
        // Robert Jenkins' 32 bit integer hash function.
        seed = ((seed + 0x7ed55d16) + (seed << 12))  & 0xffffffff;
        seed = ((seed ^ 0xc761c23c) ^ (seed >>> 19)) & 0xffffffff;
        seed = ((seed + 0x165667b1) + (seed << 5))   & 0xffffffff;
        seed = ((seed + 0xd3a2646c) ^ (seed << 9))   & 0xffffffff;
        seed = ((seed + 0xfd7046c5) + (seed << 3))   & 0xffffffff;
        seed = ((seed ^ 0xb55a4f09) ^ (seed >>> 16)) & 0xffffffff;
        return (seed & 0xfffffff) / 0x10000000;
    };
})();
var map = {}, i = 1;
var n = rand();
map[n] = true;
n = rand();
while( !(n in map) ) {
    i++;
    map[n] = true;
    n = rand();
}
console.log(i + ':' + n);

 结果：16720次产生碰撞 : 0.06406551226973534