for ($i = 0; $i < $length; $i++) {
$seed += ($multiplier * (isset($fromSeed[$string[$i]]) ? $fromSeed[$string[$i]] : 0));
$multiplier *= $fromBase;
while ($seed > $toBase) {
$result = $toSeed[$seed % $toBase] . $result;
$seed = floor($seed / $toBase);
$multiplier /= $toBase;
}
}