package Algorithm::CheckDigits::M16_001;
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 =~ /^([0-9a-f]{15})([0-9a-f])$/i) {
return $2 eq $self->_compute_checkdigit($1);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^[0-9a-f]{15}$/i) {
return $number . $self->_compute_checkdigit($number);
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^([0-9a-f]{15})([0-9a-f])$/i) {
return $1 if (uc($2) eq $self->_compute_checkdigit($1));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^([0-9a-f]{15})([0-9a-f])$/i) {
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-f]{15}$/i) {
my ($a,$b,$c);
my @digits = split(//,$number);
$a = 16;
for (my $i = 0; $i <= $#digits; $i++) {
$b = ($a % 17) + hex($digits[$i]);
$c = $b % 16;
$c = 16 unless ($c);
$a = 2 * $c;
}
return sprintf("%X",(17 - ($a % 17)) % 16);
}
return -1;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M16_001 - compute check digits for ISAN
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$isan = CheckDigits('isan');
if ($isan->is_valid('123A567B8912E01A')) {
# do something
}
$cn = $isan->complete('123A567B8912E01');
# $cn = '123A567B8912E01A'
$cd = $isan->checkdigit('123A567B8912E01A');
# $cd = '4'
$bn = $isan->basenumber('123A567B8912E01A');
# $bn = '123A567B8912E01'
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
C<a(1) = 16>
C<b(i) = a(i) % 17 +d(i)>, where C<d(i)> is the decimal value of the
hexdigit at position I<i>.
C<c(i) = b(i) % 16>
C<a(i) = c(i-1) * 2>, for I<i> greater than 1
=item 2
Beginning left for each I<i> = 1..16, C<a>, C<b>, C<c> are computed.
=item 3
The check digit is the value for C<d(16)> where C<c(16)> equals 1.
=item 4
The check digit is appended as hexadecimal value to the number.
=back
=head2 METHODS
=over 4
=item is_valid($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