hash.js

/*
Given the string str, produce a shorter random hash.
Different strings could produce the same hash, although
this is unlikely.
*/
function hash(str) {
	var i,v0,v1,abc="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
	v0=0;
	for(i=0;i<str.length;i++) {
		v1=str.charCodeAt(i);
		v0+=v0+v0^v1;
	}
	var sz=abc.length,v,res="";
	for(i=0;i<5;i++) {
		v1=parseInt(v0/sz);
		v=Math.abs(v0-v1*sz);
		res+=abc[v];
		v0=v1;
	}
	return res;
}