package Algorithm::CheckDigits::M11_001;
use 5.006;
use strict;
use warnings;
use integer;
our $VERSION = '0.53';
our @ISA = qw(Algorithm::CheckDigits);
my $cd = {
'isbn' => [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 'X', 0 ],
'ustid_pt' => [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0 ],
'hkid' => [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 'A', 0 ],
'wagonnr_br' => [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1 ],
'nhs_gb' => [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, 0 ],
'vat_sl' => [ 1, 0, 2, 3, 4, 5, 6, 7, 8, 9, 0, -1 ], # ?
};
$cd->{'issn'} = $cd->{'isbn'};
$cd->{'vatrn_pt'} = $cd->{'ustid_pt'};
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 =~ /^(.+)(.)$/) {
return uc($2) eq $self->_compute_checkdigit($1);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^[-0-9A-Za-z]+$/) {
return $number . $self->_compute_checkdigit($number);
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^(.+)(.)$/) {
return $1 if (uc($2) eq $self->_compute_checkdigit($1));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^(.+)(.)$/) {
return $2 if (uc($2) eq $self->_compute_checkdigit($1));
}
return '';
} # checkdigit()
sub _compute_checkdigit {
my $self = shift;
my $number = shift;
if ($number =~ /^[-0-9A-Za-z]+$/) {
$number =~ s/-//g;
my @digits = split(//,$number);
my $sum = 0;
my $weight = 2;
for (my $i = $#digits; $i >= 0; $i--) {
$digits[$i] = 1 + ord(uc($digits[$i])) - ord('A')
if ($digits[$i] =~ /[A-Z]/i);
$sum += $weight * $digits[$i];
++$weight;
}
$sum %= 11;
return $cd->{$self->{type}}[11-$sum] if ($cd->{$self->{type}});
}
return -1;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M11_001 - compute check digits for ISBN, ISSN, VAT RN
(PT), HKID (HK), Wagon number (BR), NHS (GB), VAT (SL)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$isbn = CheckDigits('isbn');
if ($isbn->is_valid('3-88229-192-3')) {
# do something
}
$cn = $isbn->complete('3-88229-192-');
# $cn = '3-88229-192-3'
$cd = $isbn->checkdigit('3-88229-192-3');
# $cd = '3'
$bn = $isbn->basenumber('3-88229-192-3');
# $bn = '3-88229-192-'
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
The sequence of digits is processed right to left.
Every digit is multiplied with their position in the sequence (i.e.
the digit left to the check digit has the weight 2 then 3 etc.).
With a Hongkong ID (hkid) the leftmost char is replaced with its
position in the alphabet and then multiplied with 8 (its weight).
=item 2
The sum of all products is computed.
=item 3
The sum of step 2 is taken modulo 11.
=item 4
The checkdigit is the difference of the sum from step 3 to eleven
under the following conditions:
=over 8
=item isbn,issn
If the difference is 10, the check digit is 'X'.
If the difference is 11, the check digit is 0.
=item ustid_pt
If the difference is greater then 9, the check digit is '0'.
=item hkid
If the difference is 10, the check digit is 'A'.
If the difference is 11, the check digit is 0.
=item wagonnr_br
If the difference is 10, the check digit is 0.
If the difference is 11, the check digit is 1.
=item nhs_gb
If the difference is 10, the number would not be taken.
If the difference is 11, the check digit is 0.
=item vat_sl
This is a little bit unclear, don't trust on the method for this type.
=back
=back
=head2 METHODS
=over 4
=item is_valid($number)
Returns true only if C<$number> consists solely of numbers and the last digit
is a valid check digit according to the algorithm given above.
Returns false otherwise,
=item complete($number)
The check digit for C<$number> is computed and concatenated to the end
of C<$number>.
Returns the complete number with check digit or '' if C<$number>
does not consist solely of digits and spaces.
=item basenumber($number)
Returns the basenumber of C<$number> if C<$number> has a valid check
digit.
Return '' otherwise.
=item checkdigit($number)
Returns the checkdigit of C<$number> if C<$number> has a valid check
digit.
Return '' 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