/usr/share/perl5/Business/ISBN10.pm is in libbusiness-isbn-perl 2.09-1.
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 | package Business::ISBN10;
use strict;
use base qw(Business::ISBN);
use Business::ISBN qw(:all);
use subs qw(
_checksum
INVALID_GROUP_CODE
INVALID_PUBLISHER_CODE
BAD_CHECKSUM
GOOD_ISBN
BAD_ISBN
);
use vars qw(
$VERSION
$debug
$MAX_GROUP_CODE_LENGTH
%ERROR_TEXT
);
use Carp qw(carp croak cluck);
my $debug = 0;
$VERSION = '2.09';
sub _max_length { 10 }
sub _set_type { $_[0]->{type} = 'ISBN10' }
sub _parse_prefix { '' }
sub _set_prefix {
croak "Cannot set prefix [$_[1]] on an ISBN-10" if length $_[1];
$_[0]->{prefix} = $_[1];
}
sub _hyphen_positions {
[
$_[0]->_group_code_length,
$_[0]->_group_code_length + $_[0]->_publisher_code_length,
9
]
}
sub as_isbn10 {
my $self = shift;
my $isbn10 = Business::ISBN->new( $self->isbn );
$isbn10->fix_checksum;
return $isbn10;
}
sub as_isbn13 {
my $self = shift;
my $isbn13 = Business::ISBN->new( '978' . $self->isbn );
$isbn13->fix_checksum;
return $isbn13;
}
#internal function. you don't get to use this one.
sub _checksum {
my $data = $_[0]->isbn;
return unless defined $data;
my @digits = split //, $data;
my $sum = 0;
foreach( reverse 2..10 ) {
$sum += $_ * (shift @digits);
}
#return what the check digit should be
my $checksum = (11 - ($sum % 11))%11;
$checksum = 'X' if $checksum == 10;
return $checksum;
}
1;
__END__
=head1 NAME
Business::ISBN10 - work with 10 digit International Standard Book Numbers
=head1 SYNOPSIS
See L<Business::ISBN>
=head1 DESCRIPTION
See L<Business::ISBN>
=head1 SOURCE AVAILABILITY
This source is in Github:
https://github.com/briandfoy/business--isbn
=head1 AUTHOR
brian d foy C<< <bdfoy@cpan.org> >>
=head1 COPYRIGHT AND LICENSE
Copyright (c) 2001-2014, brian d foy, All Rights Reserved.
You may redistribute this under the same terms as Perl itself.
=cut
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