package Algorithm::CheckDigits::M11_007;
use 5.006;
use strict;
use warnings;
use integer;
use version; our $VERSION = 'v1.3.2';
our @ISA = qw(Algorithm::CheckDigits);
my @weight = ( 7, 9, 10, 5, 8, 4, 2 );
sub new {
my $proto = shift;
my $type = shift;
my $class = ref($proto) || $proto;
my $self = bless({}, $class);
$self->{type} = lc($type);
return $self;
} # new()
sub is_valid {
my ($self,$number) = @_;
if ($number =~ /^(\d{7})(\d)$/) {
return uc($2) eq $self->_compute_checkdigits($1);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^(\d{7})$/) {
return "$1" . $self->_compute_checkdigits($1);
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^(\d{7})(\d)$/) {
return $1 if ($2 eq $self->_compute_checkdigits($1));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^(\d{7})(\d)$/) {
return $2 if ($2 eq $self->_compute_checkdigits($1));
}
return '';
} # checkdigit()
sub _compute_checkdigits {
my $self = shift;
my @digits = split(//,shift);
my $sum = 0;
for (my $i = 0; $i <= $#digits; $i++) {
$sum += $weight[$i] * $digits[$i];
}
$sum %= 11;
return $sum ? ($sum == 1 ? '' : 11 - $sum) : 0;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M11_007 - compute check digits for VAT Registration Number (FI)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$ustid = CheckDigits('ustid_fi');
if ($ustid->is_valid('13669598')) {
# do something
}
$cn = $ustid->complete('1366959');
# $cn = '13669598'
$cd = $ustid->checkdigit('13669598');
# $cd = '8'
$bn = $ustid->basenumber('13669598');
# $bn = '1366959';
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
Beginning left every digit is weighted with 7,9,10,5,8,4,2.
=item 2
The weighted digits are added.
=item 3
The sum from step 2 is taken modulo 11.
=item 4
The checkdigit is 11 minus the sum from step 3. Is the difference 10,
the number won't be taken. If the difference is 11, the checkdigit is
0.
=back
=head2 METHODS
=over 4
=item is_valid($number)
Returns true only if C<$number> consists solely of digits and the
rightmost digit is a valid check digit according to the algorithm given
above.
Returns false otherwise,
=item complete($number)
The check digit for C<$number> is computed and appended to the end
of C<$number>.
Returns the complete number with check digit or '' if C<$number>
does not consist solely of digits.
=item basenumber($number)
Returns the basenumber of C<$number> if C<$number> has a valid check
digit.
Return '' otherwise.
=item checkdigit($number)
Returns the check digits of C<$number> if C<$number> has valid check
digits.
Return '' otherwise.
=back
=head2 EXPORT
None by default.
=head1 AUTHOR
Mathias Weidner, C<< <mamawe@cpan.org> >>
=head1 SEE ALSO
L<perl>,
L<CheckDigits>,
F<http://www.pruefziffernberechnung.de/U/USt-IdNr.shtml#PZFI> (german)
=cut