package Algorithm::CheckDigits::M11_015;
use 5.006;
use strict;
use warnings;
use integer;
use version; our $VERSION = 'v1.3.2';
our @ISA = qw(Algorithm::CheckDigits);
my @weight = ( 2, 3, 4, 5, 6, 7 );
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)([\d ]+)$/) {
return $1 == $self->_compute_checkdigits($2);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^([\d ]+)$/) {
return $self->_compute_checkdigits($1) . $1;
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^(\d\d)([\d ]+)$/) {
return $2 if ($1 == $self->_compute_checkdigits($2));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^(\d\d)([\d ]+)$/) {
return $1 if ($1 == $self->_compute_checkdigits($2));
}
return '';
} # checkdigit()
sub _compute_checkdigits {
my ($self,$number) = @_;
$number =~ s/\s//g;
my @digits = split(//,$number);
my $sum = 0;
for (my $i = $#digits; $i >= 0; $i--) {
$sum += $weight[($#digits - $i) % 6] * $digits[$i];
}
$sum %= 11;
my $retval = (0 == $sum) ? '00' : sprintf("%02d",(11 - $sum));
$retval;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M11_015 - compute check digits for ESR5 (CH)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$ustid = CheckDigits('esr5_ch');
if ($ustid->is_valid('050001000012000 241170032660178 10304')) {
# do something
}
$cn = $ustid->complete('0001000012000 241170032660178 10304');
# $cn = '050001000012000 241170032660178 10304'
$cd = $ustid->checkdigit('0001000012000 241170032660178 10304');
# $cd = '05'
$bn = $ustid->basenumber('050001000012000 241170032660178 10304');
# $bn = '0001000012000 241170032660178 10304';
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
Beginning right all digits are weighted with the repeating
sequence 2, 3, 4, 5, 6, 7.
=item 2
The weighted digits are added.
=item 3
The sum from step 2 is taken modulo 11.
=item 4
The checkdigit is 11 minus the sum from step 3.
If the difference is 11, the checkdigit is 00.
=back
=head2 METHODS
=over 4
=item is_valid($number)
Returns true only if C<$number> consists solely of numbers (with or
without space between them) and the first two digits are valid check
digits according to the algorithm given above.
Returns false otherwise,
=item complete($number)
The check digit for C<$number> is computed and inserted before the
C<$number>.
Returns the complete number with check digit or '' if C<$number>
does not consist solely of digits, spaces.
=item basenumber($number)
Returns the basenumber of C<$number> if C<$number> has a valid check
digit.
Return '' otherwise.
=item checkdigit($number)
Returns the check digits of C<$number> if C<$number> has valid check
digits.
Return '' otherwise.
=back
=head2 EXPORT
None by default.
=head1 AUTHOR
Mathias Weidner, C<< <mamawe@cpan.org> >>
=head1 SEE ALSO
L<perl>,
L<CheckDigits>,
F<http://www.pruefziffernberechnung.de/E/Einzahlungsschein-CH.shtml> (german),
F<http://www.sic.ch/de/dl_tkicch_dta.pdf>, page 52 (german)
=cut