/usr/share/perl5/Algorithm/CheckDigits/M11_011.pm is in libalgorithm-checkdigits-perl 0.50-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 | package Algorithm::CheckDigits::M11_011;
use 5.006;
use strict;
use warnings;
use integer;
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 =~ /^([0-9]+)(\d)(B\d\d)?$/i) {
return $2 == $self->_compute_checkdigits($1);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^([0-9]+)(?:.(B\d\d))?$/
and (my $cd = $self->_compute_checkdigits($1)) ne '') {
my $tail = $2 || '';
return $1 . $cd . $tail;
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^([0-9]+)(\d)(B\d\d)?$/i) {
my $tail = $3 ? ".$3" : '';
return $1 . $tail if ($2 == $self->_compute_checkdigits($1));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^([0-9]+)(\d)(B\d\d)?$/) {
return $2 if ($2 == $self->_compute_checkdigits($1));
}
return '';
} # checkdigit()
sub _compute_checkdigits {
my $self = shift;
my $number = shift;
$number =~ s/\.//g;
my @digits = split(//,$number);
my $len = scalar(@digits) + 1;
my $sum = 0;
for (my $i = 0; $i <= $#digits; $i++) {
$sum += ($len - $i) * $digits[$i];
}
$sum %= 11;
return ($sum == 10) ? '' : $sum;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M11_011 - compute check digits for VAT Registration Number (NL)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$ustid = CheckDigits('ustid_nl');
if ($ustid->is_valid('123456782')) {
# do something
}
if ($ustid->is_valid('123456782B04')) {
# do something
}
$cn = $ustid->complete('12345678');
# $cn = '123456782'
$cn = $ustid->complete('12345678.B04');
# $cn = '123456782B04'
$cd = $ustid->checkdigit('123456782');
# $cd = '2'
$cd = $ustid->checkdigit('123456782B04');
# $cd = '2'
$bn = $ustid->basenumber('123456782');
# $bn = '12345678';
$bn = $ustid->basenumber('123456782B04');
# $bn = '12345678.B04';
=head1 DESCRIPTION
This VATRN has 12 "digits", the third last must be a I<B>, the fourth
last is the checkdigit. I don't know anything about the meaning of the
last two digits.
You may use the whole VATRN or only the first eight digits to compute
the checkdigit with this module.
=head2 ALGORITHM
=over 4
=item 1
Beginning right with the digit before the checkdigit all digits are
weighted with their position. I.e. the digit before the checkdigit is
multiplied with 2, the next with 3 and so on.
=item 2
The weighted digits are added.
=item 3
The sum from step 2 is taken modulo 11.
=item 4
If the sum from step 3 is 10, the number is discarded.
=back
=head2 METHODS
=over 4
=item is_valid($number)
Returns true only if C<$number> consists solely of numbers and hyphens
and the two digits in the middle
are valid check digits according to the algorithm given above.
Returns false otherwise,
=item complete($number)
The check digit for C<$number> is computed and inserted into the
middle of C<$number>.
Returns the complete number with check digit or '' if C<$number>
does not consist solely of digits, hyphens and spaces.
=item basenumber($number)
Returns the basenumber of C<$number> if C<$number> has a valid check
digit.
Return '' otherwise.
=item checkdigit($number)
Returns the check digits of C<$number> if C<$number> has valid check
digits.
Return '' otherwise.
=back
=head2 EXPORT
None by default.
=head1 SEE ALSO
L<perl>,
L<CheckDigits>,
F<www.pruefziffernberechnung.de>,
=head1 AUTHOR
Mathias Weidner, E<lt>mathias@weidner.in-bad-schmiedeberg.deE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2004,2005 by Mathias Weidner
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
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