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
198
199
200
201
|
package Algorithm::CheckDigits::M11_003;
use 5.006;
use strict;
use warnings;
use integer;
our @ISA = qw(Algorithm::CheckDigits);
my @weight = ( 4,2,1,6,3,7,9,10,5,8,4,2 );
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{11})(\d)$/) {
return $2 == $self->_compute_checkdigit($1);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^\d{11}$/) {
my $cd = $self->_compute_checkdigit($number);
return 0 > $cd ? '' : $number . $cd;
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^(\d{11})(\d)$/) {
return $1 if ($2 == $self->_compute_checkdigit($1));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^(\d{11})(\d)$/) {
return $2 if ($2 == $self->_compute_checkdigit($1));
}
return '';
} # checkdigit()
sub _compute_checkdigit {
my $self = shift;
my $number = shift;
if ($number =~ /^\d{11}$/) {
my @digits = split(//,$number);
my $sum = 0;
my $cf = 0;
for (my $i = 0; $i <= $#digits; $i++) {
$sum += $weight[$i] * $digits[$i];
}
$sum %= 11;
for (my $i = 0; $i <= 9; $i++) {
return $i
if (10 == ($sum + $weight[11] * $i) % 11);
}
}
return -1;
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M11_003 - compute check digits for PKZ (GDR)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$pkz = CheckDigits('pkz');
if ($pkz->is_valid('150765400354')) {
# do something
}
$cn = $pkz->complete('15076540035');
# $cn = '150765400354'
$cd = $pkz->checkdigit('150765400354');
# $cd = '4'
$bn = $pkz->basenumber('150765400354');
# $bn = '150765400354'
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 1
The checkdigit is set to 0.
=item 2
From right to left the digits are weighted (multiplied) with
2,4,8,5,10,9,7,3,6,1,2,4.
=item 3
The products are added.
=item 4
The sum of step 3 is taken modulo 11.
=item 5
The value of step 4 is added to a multiple (0..9) of the weight of the
checkdigit (2).
=item 6
The sum of step 5 is taken modulo 11.
=item 7
The checkdigit is the multiple of the weight of the checkdigit where
the value of step 6 equals 10.
=item 8
If there can't be reached a value of 10 in step 6, the number cannot
be taken as a PKZ.
=back
To validate a PKZ apply steps 2 to 4 to the complete number.
=head2 METHODS
=over 4
=item is_valid($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, E<lt>mathias@weidner.in-bad-schmiedeberg.deE<gt>
=head1 SEE ALSO
L<perl>,
L<CheckDigits>,
F<www.pruefziffernberechnung.de>.
=cut
|
