JMBAG checksum validator/calculator

jmbag.pl

#!/usr/bin/perl
use warnings;
use strict;

sub jmbag_check {
	my $jmbag = shift;
	$jmbag = sprintf "%09d", $jmbag if length $jmbag < 9;

	my $sum = 0;
	my $pos = 0;
	foreach my $tezina ( 2,3,4,5,1,2,3,4,5 ) {
		my $nr = substr($jmbag,$pos,1);
		$sum += $nr * $tezina;
		warn "# [$pos] $nr * $tezina ~ $sum\n";
		$pos++;
	}
	$sum = 11 - ( $sum % 11 );
	die "invalid" if $sum == 10;
	$sum = 0      if $sum == 11;

	if ( length $jmbag == 10 ) {
		my $ck = substr $jmbag,9,1;
		die "invalid JMBAG $jmbag [ $ck != $sum ]" if $ck != $sum;
		warn "OK $jmbag\n";
	} else {
		$jmbag .= $sum;
	}

	return $jmbag;
}

print jmbag_check($_) . "\n" foreach @ARGV;