短い URL を生成する PHP 関数

<?php
/**
 * 短网址
 */
 
function urlShort($url){
    $url= crc32($url);
    $result= sprintf("%u", $url);
    $sUrl= &#39;&#39;;
    while($result>0){
        $s= $result%62;
        if($s>35){
            $s= chr($s+61);
        } elseif($s>9 && $s<=35){
            $s= chr($s+ 55);
        }
        $sUrl.= $s;
        $result= floor($result/62);
    }
    return $sUrl;
}
 
$url = &#39;www.qttc.net&#39;;
$sUrl = urlShort($url);
 
echo &#39;<meta charset="utf-8" />&#39;;
echo &#39;网址：&#39;.$url.&#39;<br />&#39;;
echo &#39;短网址：&#39;.$sUrl;
 
?>