hashing

primeHashing.js

// von n semi-random, but repeats too quickly

function nextr(n) { var d=(n*n); if (d%100==0) d /= 100; if (d < 100) d = d*5242870; d=d.toString(); var s=d.length; return d.substring(s-6, s-2)-0 }

function nextr(n) { var d=(n*n); if (d%100==0) d /= 100; if (d < 100) d *= 132645290; d=d.toString(); var s=d.length; return d.substring(d.length / 2 - 2, d.length / 2 + 2)-0 }

function testn(n,max) { max=max||1000; for(var h={}, i=0; i<max; ++i) { n = nextr(last=n); if(h[n]) break; h[n]=last||true; } return [i,n,last,h]; }

// primes

function isprime1(n) { if(n===2 || n===5) return true; if (n%2 == 0 || n%5 ==0) return false; var ps = [3,7,11,13,17,19,23,29], c=-1, limit=1+Math.round(Math.sqrt(n)/30); while(++c < limit) { for(var i in ps) {if (n % (last=ps[i] + c*30) === 0) return ps[i]} } return true}

function isprime(n) { if(n===2 || n===5) return true; if (n%2 == 0 || n%5 ==0) return false; var ps = [3,7,11,13,17,19,23,29], c=-1, limit=1+Math.round(Math.sqrt(Math.min(16331239353195370,n))); while(++c < limit) { for(var i in ps) {if (n % (last=ps[i] + c*30) === 0) return [false,last,n/last]} } return [true,limit]}

// hashing

function bern(key, len, level) { var hash = level || 0, len=len||key.length, i; for(i=0; i<len; ++i) hash = 33*hash + key[i]; return hash; }

function fromAsc(that) { return parseInt(that, 36) }

function toKey32(str) { return str.split("").map(fromAsc); }

function keyify(str) { return str.split(/[^A-Z0-9]/i); }

function toAsc(n) { return n.toString(36); }

// keyify("Joshua Shane Weinstein").map(toKey32)[2].map(toAsc).join("")

// keyify("Joshua Shane Weinstein 1234567890 [email protected]").map(fromAsc).map(toAsc).join(" ")