/**  * 10进制转为62进制  *   * @param integer $n 10进制数值  * @return string 62进制  */  function dec62($n) {      $base = 62;      $index = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';      $ret = '';      for($t = floor(log10($n) / log10($base)); $t >= 0; $t --) {          $a = floor($n / pow($base, $t));          $ret .= substr($index, $a, 1);          $n -= $a * pow($base, $t);      }      return $ret;  }  

/**  * 62进制转为10进制  *  * @param integer $n 62进制  * @return string 10进制  */  function dec10($s) {      $base = 62;      $index = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';      $ret = 0;      $len = strlen($s) - 1;      for($t = 0; $t <= $len; $t ++) {          $ret += strpos($index, substr($s, $t, 1)) * pow($base, $len - $t);      }      return $ret;