package Algorithm::CheckDigits::M11_008;
use 5.006;
use strict;
use warnings;
use integer;
use version; our $VERSION = 'v1.3.2';
our @ISA = qw(Algorithm::CheckDigits);
my @weight = ( 2, 7, 6, 5, 4, 3, 2, 1 );
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{8})$/) {
return 0 == $self->_compute_checkdigits($1);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
return "$1" if( $number =~ /^(\d{8})$/
and 0 == $self->_compute_checkdigits($1));
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
return "$1" if( $number =~ /^(\d{8})$/
and 0 == $self->_compute_checkdigits($1));
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
return '' if( $number =~ /^(\d{8})$/
and 0 == $self->_compute_checkdigits($1));
return undef;
} # 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;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M11_008 - compute check digits for VAT Registration Number (DK)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$ustid = CheckDigits('ustid_dk');
if ($ustid->is_valid('13585628')) {
# do something
}
$cn = $ustid->complete('1358562');
# $cn = '13585628'
$cd = $ustid->checkdigit('13585628');
# $cd = '8'
$bn = $ustid->basenumber('13585628');
# $bn = '1358562';
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
Beginning left every digit is weighted with 2, 7, 6, 5, 4, 3, 2, 1
=item 2
The weighted digits are added.
=item 3
The sum from step 2 is taken modulo 11.
=item 4
The number is valid if the sum from step 3 is zero (0).
=back
=head2 METHODS
=over 4
=item is_valid($number)
Returns true only if C<$number> consists solely of numbers and the sum
computed according to the algorithm given above is 0.
Returns false otherwise,
=item complete($number)
Returns C<$number> if C<$number> is valid according to the algorithm
given above.
Return '' otherwise.
=item basenumber($number)
Returns C<$number> if C<$number> is valid according to the algorithm
given above.
Return '' otherwise.
=item checkdigit($number)
Returns '' if C<$number> is valid.
Return undef otherwise.
=back
=head2 EXPORT
None by default.
=head1 AUTHOR
Mathias Weidner, C<< <mamawe@cpan.org> >>
=head1 SEE ALSO
L<perl>,
L<CheckDigits>,
F<www.pruefziffernberechnung.de>,
=cut