oib.pl

#!/usr/bin/perl

# http://www.regos.hr/UserDocsImages/KONTROLA%20OIB-a.pdf

my $oib = 69435151530;

my ($nr,$ck) = ( substr($oib,0,10), substr($oib,-1,1) );

print "$oib -> $nr $ck\n";

my $test = $1 if $oib =~ s/^(\d)//;
print "b $test\t";
$test += 10;

while ( 1 ) {
	print "c $test\t";
	$test = $test % 10;
	$test = 10 if $test == 0;
	print "d $test\t";
	$test *= 2;
	print "e $test\t";
	$test = $test % 11;
	print "f $test\t";
	last if ! $oib;
	$test += $1 if $oib =~ s/^(\d)//;
	print "\nb $1\t";
}
$test = 11 - $test;
$test = 0 if $test == 10;
print "\n$ck ? ",$test," ", $ck == $test ? "ok" : "error","\n";