package Algorithm::CheckDigits::M11_011;
use 5.006;
use strict;
use warnings;
use integer;
our $VERSION = '0.53';
our @ISA = qw(Algorithm::CheckDigits);
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 =~ /^([0-9]+)(\d)(B\d\d)?$/i) {
return $2 == $self->_compute_checkdigits($1);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^([0-9]+)(?:.(B\d\d))?$/
and (my $cd = $self->_compute_checkdigits($1)) ne '') {
my $tail = $2 || '';
return $1 . $cd . $tail;
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^([0-9]+)(\d)(B\d\d)?$/i) {
my $tail = $3 ? ".$3" : '';
return $1 . $tail if ($2 == $self->_compute_checkdigits($1));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^([0-9]+)(\d)(B\d\d)?$/) {
return $2 if ($2 == $self->_compute_checkdigits($1));
}
return '';
} # checkdigit()
sub _compute_checkdigits {
my $self = shift;
my $number = shift;
$number =~ s/\.//g;
my @digits = split(//,$number);
my $len = scalar(@digits) + 1;
my $sum = 0;
for (my $i = 0; $i <= $#digits; $i++) {
$sum += ($len - $i) * $digits[$i];
}
$sum %= 11;
return ($sum == 10) ? '' : $sum;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M11_011 - compute check digits for VAT Registration Number (NL)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$ustid = CheckDigits('ustid_nl');
if ($ustid->is_valid('123456782')) {
# do something
}
if ($ustid->is_valid('123456782B04')) {
# do something
}
$cn = $ustid->complete('12345678');
# $cn = '123456782'
$cn = $ustid->complete('12345678.B04');
# $cn = '123456782B04'
$cd = $ustid->checkdigit('123456782');
# $cd = '2'
$cd = $ustid->checkdigit('123456782B04');
# $cd = '2'
$bn = $ustid->basenumber('123456782');
# $bn = '12345678';
$bn = $ustid->basenumber('123456782B04');
# $bn = '12345678.B04';
=head1 DESCRIPTION
This VATRN has 12 "digits", the third last must be a I<B>, the fourth
last is the checkdigit. I don't know anything about the meaning of the
last two digits.
You may use the whole VATRN or only the first eight digits to compute
the checkdigit with this module.
=head2 ALGORITHM
=over 4
=item 1
Beginning right with the digit before the checkdigit all digits are
weighted with their position. I.e. the digit before the checkdigit is
multiplied with 2, the next with 3 and so on.
=item 2
The weighted digits are added.
=item 3
The sum from step 2 is taken modulo 11.
=item 4
If the sum from step 3 is 10, the number is discarded.
=back
=head2 METHODS
=over 4
=item is_valid($number)
Returns true only if the first eight positions of C<$number> consist
solely of digits (maybe followed by 'B' and to further digits)
and the eighth digit is a valid check digit according to the algorithm
given above.
Returns false otherwise,
=item complete($number)
The check digit for C<$number> is computed and inserted at position
eight of C<$number>.
Returns the complete number with check digit or '' if C<$number>
does not consist solely of digits a dot and maybe 'B' at the ninth
position.
=item basenumber($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 SEE ALSO
L<perl>,
L<CheckDigits>,
F<www.pruefziffernberechnung.de>,
=head1 AUTHOR
Mathias Weidner, C<< <mamawe@cpan.org> >>
=head1 COPYRIGHT AND LICENSE
Copyright 2004,2005 by Mathias Weidner
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut