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package Algorithm::CheckDigits::MXX_006;
use 5.006;
use strict;
use warnings;
use integer;
use Data::Dumper;
our @ISA = qw(Algorithm::CheckDigits);
our @inverted = (0, 4, 3, 2, 1, 5, 6, 7, 8, 9 );
my $perm = [
[ 1, 5, 7, 6, 2, 8, 3, 0, 9, 4, ],
[ 5, 8, 0, 3, 7, 9, 6, 1, 4, 2, ],
[ 8, 9, 1, 6, 0, 4, 3, 5, 2, 7, ],
[ 9, 4, 5, 3, 1, 2, 6, 8, 7, 0, ],
[ 4, 2, 8, 6, 5, 7, 3, 9, 0, 1, ],
[ 2, 7, 9, 3, 8, 0, 6, 4, 1, 5, ],
[ 7, 0, 4, 6, 9, 1, 3, 2, 5, 8, ],
[ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ],
[ 1, 5, 7, 6, 2, 8, 3, 0, 9, 4, ],
[ 5, 8, 0, 3, 7, 9, 6, 1, 4, 2, ],
[ 8, 9, 1, 6, 0, 4, 3, 5, 2, 7, ],
];
my $dieder = [
[ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ],
[ 1, 2, 3, 4, 0, 6, 7, 8, 9, 5, ],
[ 2, 3, 4, 0, 1, 7, 8, 9, 5, 6, ],
[ 3, 4, 0, 1, 2, 8, 9, 5, 6, 7, ],
[ 4, 0, 1, 2, 3, 9, 5, 6, 7, 8, ],
[ 5, 9, 8, 7, 6, 0, 4, 3, 2, 1, ],
[ 6, 5, 9, 8, 7, 1, 0, 4, 3, 2, ],
[ 7, 6, 5, 6, 8, 2, 1, 0, 4, 3, ],
[ 8, 7, 6, 5, 9, 3, 2, 1, 0, 4, ],
[ 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, ],
];
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+)(\d)$/i) {
return 1 if ($2 == $self->_compute_checkdigit(uc($1)));
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^\d+$/i) {
return $number . $self->_compute_checkdigit(uc($number));
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^(\d+)(\d)$/i) {
return $1 if ($2 == $self->_compute_checkdigit(uc($1)));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^(\d+)(\d)$/i) {
return $2 if ($2 == $self->_compute_checkdigit(uc($1)));
}
return '';
} # checkdigit()
sub _compute_checkdigit {
my $self = shift;
my $number = shift;
my $input = shift;
my $c = 0; # initialize check at 0
my $digit = 0;
my $i = 0; my $r;
foreach $digit (reverse split(//, $number)) {
# This was jonathans implementation, his permutation
# table is offset by one compared to the one I already
# took in MXX_003.pm and reused here
# $c = $di->[$c]->[$f->[($i+1) % 8]->[$digit]];
$c = $dieder->[$c]->[$perm->[$i % 8]->[$digit]];
$i++;
}
return $inverted[$c];
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::MXX_006 - compute check digits with Verhoeff scheme
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$verhoeff = CheckDigits('verhoeff');
if ($verhoeff->is_valid('14567894')) {
# do something
}
$cn = $verhoeff->complete('1456789');
# $cn = '14567894'
$cd = $verhoeff->checkdigit('14567894');
# $cd = '4'
$bn = $verhoeff->basenumber('14567894');
# $bn = '1456789'
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
Right to left all digits are permutated according to a permutation table.
=item 2
The permutated digits are combined using a dider table. The first
with the second, the result with the third, this result with the
fourth and so on.
=item 3
The result of the last combination in the dider table is in such a
way combined that the result is 0 (zero). The number used for this
combination is the checksum.
=back
For details look at the source.
=head2 METHODS
=over 4
=item is_valid($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<$number>
does not consist solely of digits.
=item basenumber($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, E<lt>mathias@weidner.in-bad-schmiedeberg.deE<gt>
=head1 THANKS
Jonathan Peters wrote L<Algorithm::Verhoeff> from which I took the
routine to compute the checkdigits.
=head1 SEE ALSO
L<perl>,
L<CheckDigits>,
L<http://www.cs.utsa.edu/~wagner/laws/verhoeff.html>,
L<http://www.cs.nmsu.edu/~cssem/Dickcheckdoc.pdf>
=cut
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