PHP generates short URL | two implementation methods

<?php
/**
 * Created by PhpStorm.
 * User: yangyulong/anziguoer@sina.com
 * Date: 2015/5/28
 * Time: 15:55
 */
function shortUrl($url){
    $base32 = array (
        &#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;d&#39;, &#39;e&#39;, &#39;f&#39;, &#39;g&#39;, &#39;h&#39;,
        &#39;i&#39;, &#39;j&#39;, &#39;k&#39;, &#39;l&#39;, &#39;m&#39;, &#39;n&#39;, &#39;o&#39;, &#39;p&#39;,
        &#39;q&#39;, &#39;r&#39;, &#39;s&#39;, &#39;t&#39;, &#39;u&#39;, &#39;v&#39;, &#39;w&#39;, &#39;x&#39;,
        &#39;y&#39;, &#39;z&#39;, &#39;0&#39;, &#39;1&#39;, &#39;2&#39;, &#39;3&#39;, &#39;4&#39;, &#39;5&#39;
    );
 
    $hex = md5($url);
    $hexLength = strlen($hex);
    $subHexLen = $hexLength / 8;
 
    $output = array();
    for ($i = 0; $i < $subHexLen; $i++) {
        //每循环一次取到8位
        $subHex = substr ($hex, $i * 8, 8);
        $int = 0x3FFFFFFF & (1 * (&#39;0x&#39;.$subHex));
        $out = &#39;&#39;;
 
        for ($j = 0; $j < 6; $j++) {
            $val = 0x0000001F & $int;
            $out .= $base32[$val];
            $int = $int >> 5;
        }
 
        $output[] = $out;
    }
 
    return $output;
}
 
 
function shortUrl2($url){
    $result = sprintf("%u",crc32($url));
    $show = &#39;&#39;;
    while($result  >0){
        $s = $result % 62;
        if($s > 35){
            $s=chr($s+61);
        }elseif($s>9 && $s<=35){
            $s=chr($s+55);
        }
        $show .= $s;
        $result = floor($result / 62);
    }
 
    return $show;
}
 
echo shortUrl2(&#39;http://baidu.com&#39;);