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package Algorithm::CheckDigits::MBase_003;
use 5.006;
use strict;
use warnings;
use integer;
our @ISA = qw(Algorithm::CheckDigits);
my @weight = ( 6, 3, 7, 9, 10, 5, 8, 4, 2, 1 );
my %table_to = (
'0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4,
'5' => 5, '6' => 6, '7' => 7, '8' => 8, '9' => 9,
'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,
);
my @table_from = (
'0', '1', '2', '3', '4',
'5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E',
'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O',
'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y',
'Z', '#',
);
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 =~ /^(.*)(.)$/) {
return uc($2) eq $self->_compute_checkdigits($1);
}
return ''
} # is_valid()
sub complete {
my ($self,$number) = @_;
if ($number =~ /^(.*)$/) {
return "$1"
. $self->_compute_checkdigits($1)
}
return '';
} # complete()
sub basenumber {
my ($self,$number) = @_;
if ($number =~ /^(.*)(.)$/) {
return "$1" if ($2 eq $self->_compute_checkdigits($1));
}
return '';
} # basenumber()
sub checkdigit {
my ($self,$number) = @_;
if ($number =~ /^(.*)(.)$/) {
return $2 if ($2 eq $self->_compute_checkdigits($1));
}
return '';
} # checkdigit()
sub _compute_checkdigits {
my $self = shift;
my $number = shift;
my $digit;
my @digits = split(//,$number);
my $even = 0;
my $sum1 = 0;
my $sum2 = 0;
for (my $i = $#digits; $i>= 0; $i--) {
if (uc($digits[$i]) =~ /[0-9A-Z]/) {
$digit = $table_to{uc($digits[$i])};
} else {
$digit = 36;
}
$sum1 += 3 * $digit unless ($even);
$sum2 += $digit if ($even);
$even = not $even;
}
my $sum = 37 - (($sum1 + $sum2) % 37);
return $table_from[$sum];
} # _compute_checkdigit()
# Preloaded methods go here.
1;
__END__
=head1 NAME
CheckDigits::MBase_003 - compute check digits for SICI (Serial Item
and Contribution Identifier)
=head1 SYNOPSIS
use Algorithm::CheckDigits;
$sici = CheckDigits('sici');
if ($sici->is_valid('0784-8679(20040308)6:<138>2.0.TX;2-H')) {
# do something
}
$cn = $sici->complete('0784-8679(20040308)6:<138>2.0.TX;2-');
# $cn = '0784-8679(20040308)6:<138>2.0.TX;2-H'
$cd = $sici->checkdigit('0784-8679(20040308)6:<138>2.0.TX;2-H');
# $cd = 'H'
$bn = $sici->basenumber('0784-8679(20040308)6:<138>2.0.TX;2-H');
# $bn = '0784-8679(20040308)6:<138>2.0.TX;2-';
=head1 DESCRIPTION
=head2 ALGORITHM
=over 4
=item 0
In the string describing the number all letters (A-Z) are replaced
with numbers 10-35 accordingly. All other non-numbers are replaced by
36.
=item 1
Beginning right the numbers at all odd positions are added.
=item 2
The sum from step 1 is multiplied by 3.
=item 3
Beginning right the numbers at all even positions are added.
=item 4
The sums from step 2 and 3 are added.
=item 5
The sum from step 4 is taken modulo 37.
=item 6
The checksum is 37 minus the sum from step 5 where numbers from 10 to
35 are represented by 'A' to 'Z' accordingly and 36 is represented by
'#'.
=back
=head2 METHODS
=over 4
=item is_valid($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 AUTHOR
Mathias Weidner, E<lt>mathias@weidner.in-bad-schmiedeberg.deE<gt>
=head1 SEE ALSO
L<perl>,
L<CheckDigits>,
F<www.pruefziffernberechnung.de>,
F<http://sunsite.berkeley.edu/SICI/sici.pdf>
=cut
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