# vim: set ts=4 sw=4 tw=78 si et:
package Algorithm::CheckDigits::M11_017;
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 ( $number =~ /^([-\d]+)(\d)$/ ) {
return $2 eq $self->_compute_checkdigit($1);
}
return '';
} # is_valid()
sub complete {
my ( $self, $number ) = @_;
if ( $number =~ /^[-\d]+$/ ) {
my $cd = $self->_compute_checkdigit($number);
return $number . $cd unless 0 > $cd;
}
return '';
} # complete()
sub basenumber {
my ( $self, $number ) = @_;
if ( $number =~ /^([-\d]+)(\d)$/ ) {
return $1 if ( $2 eq $self->_compute_checkdigit($1) );
}
return '';
} # basenumber()
sub checkdigit {
my ( $self, $number ) = @_;
if ( $number =~ /^([-\d.]+)(\d)$/ ) {
return $2 if ( $2 eq $self->_compute_checkdigit($1) );
}
return '';
} # checkdigit()
sub _compute_checkdigit {
my $self = shift;
my $number = shift;
my ( $cd1, $cd2 ) = ( '', '' );
$number =~ s/[-]//g;
my @digits = split //, $number;
my $sum = 0;
for ( my $i = 0; $i <= $#digits; $i++ ) {
$sum += ( $i + 1 ) * $digits[$i];
}
$sum %= 11;
return 0 if ( 9 < $sum );
return $sum;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M11_017 - compute check digits for EC-No, EINECS, ELINCS
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$ecno = CheckDigits('ecno');
if ($ecno->is_valid('200-236-6')) {
# do something
}
$cn = $ecno->complete('200-236-');
# $cn = '200-236-6'
$cd = $ecno->checkdigit('200-236-6');
# $cd = '6'
$bn = $ecno->basenumber('200-236-6');
# $bn = '200-236-'
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
From left to right all digits are multiplied with their position
in the sequence.
=item 2
The sum of all products is computed.
=item 3
The sum of step 2 is taken modulo 11.
The checkdigit is the last digit of the result.
=back
=head2 METHODS
=over 4
=item is_valid($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<http://en.wikipedia.org/wiki/EC-No>.
=cut