class Base62 {     private $string = "vPh7zZwA2LyU4bGq5tcVfIMxJi6XaSoK9CNp0OWljYTHQ8REnmu31BrdgeDkFs";     public function base62_encode($str) {         $out = '';         for($t=floor(log10($str)/log10(62)); $t>=0; $t--) {             $a = floor($str / pow(62, $t));             $out = $out.substr($this->string, $a, 1);             $str = $str - ($a * pow(62, $t));         }           return $out;     }       public function base62_decode($str) {         $out = 0;         $len = strlen($str) - 1;         for($t=0; $t<=$len; $t++) {             $out = $out + strpos($this->string, substr($str, $t, 1)) * pow(62, $len - $t);         }           return substr(sprintf("%f", $out), 0, -7);     }   }

$str = 1; $object = new Base62(); echo $object->base62_encode($str) . "n"; echo $object->base62_decode($object->base62_encode($str)) . "n";