/**
  * 生成特征值
  * @param $url  $subdomain.$maindomain.$path.$readid
  */
 function InitFeature($url)
 {
     $md5Url = md5($url);
     $this->md5Url = $md5Url;
     $this->arrFeature = str_split(toTen(substr($md5Url, 0, 8)) . toTen(substr($md5Url, 8, 8)) . toTen(substr($md5Url, 16, 8)) . toTen(substr($md5Url, 24, 8)), 1);
     $arrLibFeature = array();
     for ($i = 0; $i < 7; $i++) {
         $arrLibFeature[$i] = ToTen(substr($md5Url, $i * 4, 4)) + 1;
         $arrLibFeature[$i + 7] = ToTen(substr($md5Url, $i * 4 + 1, 4)) + 1;
         $arrLibFeature[$i + 14] = ToTen(substr($md5Url, $i * 4 + 2, 4)) + 1;
         $arrLibFeature[$i + 21] = ToTen(substr($md5Url, $i * 4 + 3, 4)) + 1;
     }
     $this->arrLibFeature = $arrLibFeature;
 }
/**
 * 16进制转36进制
 * @param $num
 * @param $start_no
 * @param $len
 * @return string
 */
function Md5To36($num, $start_no, $len)
{
    $arrTrans = array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z');
    $tenNo = ToTen(substr($num, $start_no, $len));
    $resultNo = '';
    do {
        $a = ceil($tenNo / 36);
        $b = fmod(floatval($tenNo), 36);
        $tenNo = $a;
        $resultNo = $arrTrans[$b] . $resultNo;
    } while ($tenNo >= 36);
    $resultNo = $arrTrans[$tenNo] . $resultNo;
    return $resultNo;
}