/usr/share/perl5/Algorithm/CheckDigits/M97_002.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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 | package Algorithm::CheckDigits::M97_002;
# vim: set sw=4 ts=4 tw=78 et si:
use 5.006;
use strict;
use warnings;
use integer;
#use Math::BigInt;
our @ISA = qw(Algorithm::CheckDigits);
my %subst = (
A => 10, B => 11, C => 12, D => 13, E => 14,
F => 15, G => 16, H => 17, I => 18, J => 19,
K => 20, L => 21, M => 22, N => 23, O => 24,
P => 25, Q => 26, R => 27, S => 28, T => 29,
U => 30, V => 31, W => 32, X => 33, Y => 34,
Z => 35,
);
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 $self = shift;
if (my ($checkdigit,$number) = _prepare_number(shift)) {
return $checkdigit eq _compute_checkdigit($number);
}
return ''
} # is_valid()
sub complete {
my $self = shift;
my $incomplete = uc(shift);
if (my ($checkdigit,$number) = _prepare_number($incomplete)) {
$incomplete =~ /^(..)..(.+)/;
return $1 . _compute_checkdigit($number) . $2;
}
return '';
} # complete()
sub basenumber {
my $self = shift;
my $unchecked = shift;
if (my ($checkdigit,$number) = _prepare_number($unchecked)) {
$unchecked =~ /^(..)..(.+)/;
return $1.'00'.$2
if ($checkdigit eq _compute_checkdigit($number));
}
return '';
} # basenumber()
sub checkdigit {
my $self = shift;
if (my ($checkdigit,$number) = _prepare_number(shift)) {
return $checkdigit
if ($checkdigit eq _compute_checkdigit($number));
}
return '';
} # checkdigit()
sub _compute_checkdigit {
my $number = shift;
# my $bignum = Math::BigInt->new($number);
# my $mod = $bignum % 97;
#
# A comparison with Benchmark::compthese() brought:
#
# Rate bignum 9_digits
# bignum 2502/s -- -95%
# 9_digits 46225/s 1748% --
#
# so I reverted _compute_checkdigit to this code.
# Thanks to Detlef Pilzecker for making me aware of this.
my $mod = '';
while ($number ne '') {
$number = $mod . $number;
$mod = substr($number,0,9,'') % 97;
}
return sprintf("%02d",(98 - $mod));
} # _compute_checkdigit()
sub _prepare_number {
my $number = uc(shift);
$number =~ s/\s//g;
if ($number =~ /^([A-Z]{2})(\d\d)([A-Z\d]{2,30})$/) {
my $checkdigit = $2;
$number = $3 . $1 . '00';
$number =~ s/([A-Z])/$subst{$1}/g;
return ($checkdigit,$number);
}
return;
} # _prepare_number()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::M97_002 - compute check digits for International Bank
Account Number (IBAN)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$iban = CheckDigits('iban');
if ($iban->is_valid('DE88 2008 0000 09703 7570 0')) {
# do something
}
$cn = $iban->complete('DE00 2008 0000 09703 7570 0');
# $cn = 'DE88 2008 0000 09703 7570 0'
$cd = $iban->checkdigit('DE88 2008 0000 09703 7570 0');
# $cd = '88'
$bn = $iban->basenumber('DE88 2008 0000 09703 7570 0');
# $bn = 'DE00 2008 0000 09703 7570 0'
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 0
The IBAN number must be prepared. The first two letters and the
checksum will be moved to the right end. The letters are substituted
according to the substitute table and the checksum is set to '00'.
=item 1
The whole number is taken modulo 97.
=item 2
The checksum is difference between 98 and the sum of step 2.
=item 3
If the checksum is smaller then 10, a leading zero will be
prepended.
=back
=head2 METHODS
=over 4
=item is_valid($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($number)
Returns the checkdigits of C<$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 THANKS
Detlef Pilzecker pointed out to me that there may be more letters as the first
two in an IBAN number. He also made me aware of a faster method to compute the
check number than using Math::BigInt.
=head1 SEE ALSO
L<perl>,
L<CheckDigits>,
F<www.pruefziffernberechnung.de>,
F<www.sic.ch/en/tkicch_home/tkicch_standardization/
tkicch_financialinstitutions_ibanipi.htm>.
=cut
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