短縮URLを生成する

functionbase62($x)
{
 $show = '';
 while($x > 0) {
 $s = $x % 62;
 if ($s > 35) {
 $s = chr($s+61);
 } elseif ($s > 9 && $s  $s = chr($s + 55);
 }
 $show .= $s;
 $x = Floor($x/62) );
 }
 return $show;
}

function urlShort($url)
{
 $url = crc32($url);
 $result = sprintf("%u", $url);
 returnbase62($result);
}

echo urlShort("http://code.google.com/p/rfphp4zf");