sub encode{
 my $mode = shift;
 my $area = shift;
 my $subarea = shift;
 my $str;
 my $bitstr=unpack("b4",pack("v",$mode)).
 	unpack("b16",pack("v",$area)).
 	unpack("b16",pack("v",$subarea));
 for (0..5){
 	my $val=unpack('c',pack('b6',substr($bitstr,$_*6,6)));
 	if ($val<10){
 		$str.=pack('c',$val+48);
 	}elsif ($val<36){
 		$str.=pack('c',$val+65-10);
 	}elsif ($val<62){
 		$str.=pack('c',$val+97-36);
 	}elsif ($val == 63){
 		$str.=pack('c',37);
 	}elsif ($val == 64){
 		$str.=pack('c',45);
 	}
 }
 $str;
}

sub decode{
	my $str = shift;
 my $bitstr;
	for (split //, $str){
	 my $item = unpack('c', $_);
  for ($item){
			$val = 64, last if $item == 45;
			$val = 63, last if $item == 37;
			$val = $item-97+36, last if $item >= 97;
			$val = $item-65+10, last if $item >= 65;
			$val = $item-48, last if $item >= 48;
  }
		$bitstr .= unpack("b6",pack("v",$val)); 
	}
 $mode = unpack('c',pack('b4',substr( $bitstr,0,4)));
 $area = unpack('v',pack('b16',substr( $bitstr,4,16)));
 $subarea = unpack('v',pack('b16',substr( $bitstr,20,16)));
 ($mode, $area, $subarea);
}

$encoded=encode(15,13,13);
$decoded=join ', ', decode( $encoded );

print "Encoded: $encoded\nDecoded array: $decoded\n";