—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__
=encoding iso-8859-1
=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');
# $bn = '1456789'
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
Right to left all digits are permutated according to a permutation table.
=item 2
The permutated digits are combined using a diëder table. The first
with the second, the result with the third, this result with the
fourth and so on.
=item 3
The result of the last combination in the diëder table is in such a
way combined that the result is 0 (zero). The number used for this
combination is the checksum.
=back
For details look at the source.
=head2 METHODS
=over 4
=item is_valid($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, C<< <mamawe@cpan.org> >>
=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