Business::ISBN - work with International Standard Book Numbers

Business-ISBN documentation Contained in the Business-ISBN distribution.

Index

Code Index:

NAME

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Business::ISBN - work with International Standard Book Numbers

SYNOPSIS

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	use Business::ISBN;

	# 10 digit ISBNs
	$isbn10 = Business::ISBN->new('1565922573');
	$isbn10 = Business::ISBN->new('1-56592-257-3');

	# 13 digit ISBNs
	$isbn13 = Business::ISBN->new('978-0-596-52724-2');

	# convert
	$isbn10 = $isbn13->as_isbn10;    # for the 978 prefixes

	$isbn13 = $isbn10->as_isbn13;

	# maybe you don't care what it is as long as everything works
	$isbn = Business::ISBN->new( $ARGV[0] );

	#print the ISBN with hyphens at usual positions 
	print $isbn->as_string;

	#print the ISBN with hyphens at specified positions.
	#this not does affect the default positions
	print $isbn->as_string([]);

	#print the group code or publisher code
	print $isbn->group_code;

	print $isbn->publisher_code;

	#check to see if the ISBN is valid
	$isbn->is_valid;

	#fix the ISBN checksum.  BEWARE:  the error might not be
	#in the checksum!
	$isbn->fix_checksum;

	# create an EAN13 barcode in PNG format
	$isbn->png_barcode;

DESCRIPTION

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This modules handles International Standard Book Numbers, including ISBN-10 and ISBN-13.

Function interface

valid_isbn_checksum( ISBN10 | ISBN13 )

This function is exportable on demand, and works for either 10 or 13 character ISBNs).

	use Business::ISBN qw( valid_isbn_checksum );

Returns 1 if the ISBN is a valid ISBN with the right checksum.

Returns 0 if the ISBN has valid prefix and publisher codes, but an invalid checksum.

Returns undef if the ISBN does not validate for any other reason.

Object interface

new($isbn)

The constructor accepts a scalar representing the ISBN.

The string representing the ISBN may contain characters other than [0-9xX], although these will be removed in the internal representation. The resulting string must look like an ISBN - the first nine characters must be digits and the tenth character must be a digit, 'x', or 'X'.

The constructor attempts to determine the group code and the publisher code. If these data cannot be determined, the constructor sets $obj->is_valid to something other than GOOD_ISBN. An object is still returned and it is up to the program to check $obj->is_valid for one of five values (which may be exported on demand). The actual values of these symbolic versions are the same as those from previous versions of this module which used literal values.



	Business::ISBN::INVALID_PUBLISHER_CODE
	Business::ISBN::INVALID_GROUP_CODE
	Business::ISBN::BAD_CHECKSUM
	Business::ISBN::GOOD_ISBN
	Business::ISBN::BAD_ISBN

If you have one of these values and want to turn it into a string, you can use the %Business::ISBN::ERROR_TEXT hash, which is exportable by asking for it explicitly in the import list.

	use Business::ISBN qw(%ERROR_TEXT);

The string passed as the ISBN need not be a valid ISBN as long as it superficially looks like one. This allows one to use the fix_checksum() method. Despite the disclaimer in the discussion of that method, the author has found it extremely useful. One should check the validity of the ISBN with is_valid() rather than relying on the return value of the constructor. If all one wants to do is check the validity of an ISBN, one can skip the object-oriented interface and use the valid_isbn_checksum() function which is exportable on demand.

If the constructor decides it cannot create an object, it returns undef. It may do this if the string passed as the ISBN cannot be munged to the internal format meaning that it does not even come close to looking like an ISBN.

Instance methods

input_isbn

Returns the starting ISBN. Since you may insert hyphens or fix checksums, you might want to see the original data.

common_data

Returns the starting ISBN after normalization, which removes anything that isn't a digit or a valid checksum character.

isbn

Returns the current value of ISBN, even if it has an invalid checksum. This is the raw data so it doesn't have the hyphens. If you want hyphenation, try as_string.

The isbn method should be the same as as_string( [] ).

error

Return the error code for the reason the ISBN isn't valid. The return value is a key in %ERROR_TEXT.

is_valid

Return true if the ISBN is valid, meaning that it has a valid prefix (for ISBN-13), group code, and publisher code; and its checksum validates.

type

Returns either ISBN10 or ISBN13.

prefix

Returns the prefix for the ISBN. This is currently either 978 or 979 for ISBN-13. It returns the empty string (so, a defined value) for ISBN-10.

group_code

Returns the group code for the ISBN. This is the numerical version, for example, '0' for the English group. The valid group codes come from Business::ISBN::Data.

group

Returns the group name for the ISBN. This is the string version. For instance, 'English' for the '0' group. The names come from Business::ISBN::Data.

publisher_code

Returns the publisher code for the ISBN. This is the numeric version, for instance '596' for O'Reilly Media.

article_code

Returns the article code for the ISBN. This is the numeric version that uniquely identifies the item.

checksum

Returns the checksum code for the ISBN. This checksum may not be valid since you can create an object an fix the checksum later with fix_checksum.

is_valid_checksum

Returns Business::ISBN::GOOD_ISBN for valid checksums and Business::ISBN::BAD_CHECKSUM otherwise. This does not guarantee that the rest of the ISBN is actually assigned to a book.

fix_checksum

Checks the checksum and modifies the ISBN to set it correctly if needed.

as_string(), as_string([])

Return the ISBN as a string. This function takes an optional anonymous array (or array reference) that specifies the placement of hyphens in the string. An empty anonymous array produces a string with no hyphens. An empty argument list automatically hyphenates the ISBN based on the discovered group and publisher codes. An ISBN that is not valid may produce strange results.

The positions specified in the passed anonymous array are only used for one method use and do not replace the values specified by the constructor. The method assumes that you know what you are doing and will attempt to use the least three positions specified. If you pass an anonymous array of several positions, the list will be sorted and the lowest three positions will be used. Positions less than 1 and greater than 12 are silently ignored.

A terminating 'x' is changed to 'X'.

as_isbn10

Returns a new ISBN object. If the object is already ISBN-10, this method clones it. If it is an ISBN-13 with the prefix 978, it returns the ISBN-10 equivalent. For all other cases it returns undef.

as_isbn13

Returns a new ISBN object. If the object is already ISBN-13, this method clones it. If it is an ISBN-10, it returns the ISBN-13 equivalent with the 978 prefix.

xisbn

In scalar context, returns an anonymous array of related ISBNs using xISBN. In list context, returns a list.

This feature requires LWP::Simple.

png_barcode

Returns image data in PNG format for the barcode for the ISBN. This works with ISBN-10 and ISBN-13. The ISBN-10s are automaically converted to ISBN-13.

This requires GD::Barcode::EAN13.

BUGS

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*

TO DO

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* i would like to create the bar codes with the price extension

SOURCE AVAILABILITY

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This source is in Github:

    http://github.com/briandfoy/business--isbn/tree/master

AUTHOR

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brian d foy <bdfoy@cpan.org>

COPYRIGHT AND LICENSE

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Copyright (c) 2001-2009, brian d foy, All Rights Reserved.

You may redistribute this under the same terms as Perl itself.

CREDITS

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Thanks to Mark W. Eichin <eichin@thok.org> for suggestions and discussions on EAN support.

Thanks to Andy Lester <andy@petdance.com> for lots of bug fixes and testing.

Ed Summers <esummers@cpan.org> has volunteered to help with this module.

Business-ISBN documentation Contained in the Business-ISBN distribution. 
# $Revision: 2.16 $
# $Id: ISBN.pm,v 2.16 2008/08/09 04:29:55 comdog Exp $
package Business::ISBN;
use strict;


# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
# # Boring set up stuff
use subs qw( 
	_common_format
	INVALID_GROUP_CODE
	INVALID_PUBLISHER_CODE
	BAD_CHECKSUM
	GOOD_ISBN
	BAD_ISBN
	);
use vars qw( $VERSION @ISA @EXPORT_OK %EXPORT_TAGS $debug %group_data
	$MAX_GROUP_CODE_LENGTH %ERROR_TEXT );

use Carp qw(carp croak cluck);
use base qw(Exporter);

use Business::ISBN::Data 20081208; # now a separate module
# ugh, hack
*group_data = *Business::ISBN::country_data;
sub _group_data { $group_data{ $_[1] } }

sub _max_group_code_length  { $Business::ISBN::MAX_COUNTRY_CODE_LENGTH };
sub _max_publisher_code_length  { 
	  $_[0]->_max_length    

	- $_[0]->_prefix_length     # prefix
	
	- $_[0]->_group_code_length # group
	- 1                         # article
	- 1;                        # checksum
	};

sub _publisher_ranges
	{	
	my $self = shift;
	[ @{ $self->_group_data( $self->group_code )->[1] } ];
	}

my $debug = 0;

BEGIN {
	@EXPORT_OK = qw(
		INVALID_GROUP_CODE INVALID_PUBLISHER_CODE
		BAD_CHECKSUM GOOD_ISBN BAD_ISBN 
		INVALID_PREFIX
		%ERROR_TEXT
		valid_isbn_checksum
		);

	%EXPORT_TAGS = ( 
		'all' => \@EXPORT_OK,	
		);
	};
	
$VERSION = "2.05";

sub INVALID_PREFIX         () { -4 };
sub INVALID_GROUP_CODE     () { -2 };
sub INVALID_PUBLISHER_CODE () { -3 };
sub BAD_CHECKSUM           () { -1 };
sub GOOD_ISBN              () {  1 };
sub BAD_ISBN               () {  0 };

	
%ERROR_TEXT = (
	 0 => "Bad ISBN",
	 1 => "Good ISBN",
	-1 => "Bad ISBN checksum",
	-2 => "Invalid group code",
	-3 => "Invalid publisher code",
	-4 => "Invalid prefix (must be 978 or 979)",
	);

use Business::ISBN10;
use Business::ISBN13;


sub valid_isbn_checksum
	{
	my $isbn = shift;
	
	my $obj =  Business::ISBN->new( $isbn );
	
	return 1 if $obj->is_valid_checksum == GOOD_ISBN;
	return 0 if $obj->is_valid_checksum == BAD_CHECKSUM;
	return;
	}
	

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
sub new
	{
	my $class       = shift;
	my $input_data  = shift;
	my $common_data = _common_format $input_data;

	return unless $common_data;
		
	my $self = { 
		input_isbn  => $input_data,
		common_data => $common_data 
		};
	
	my $isbn = do {
		if( length( $common_data ) == 10 )
			{
			bless $self, 'Business::ISBN10';
			}
		elsif( length( $common_data ) == 13 )
			{
			bless $self, 'Business::ISBN13';
			}
		else
			{
			return BAD_ISBN;
			}
		};

	$self->_init( $common_data );
	$self->_parse_isbn( $common_data );
		
	return $isbn;
	}


sub input_isbn               {   $_[0]->{'input_isbn'}  }


sub common_data              {   $_[0]->{'common_data'} }



sub isbn                     {   $_[0]->{'isbn'}                              }


sub error                    {   $_[0]->{'valid'}                             }


sub is_valid                {   $_[0]->{'valid'} eq GOOD_ISBN                }


sub type                     {   $_[0]->{'type'}                              }



sub prefix                   {   $_[0]->{'prefix'}                            }
sub _prefix_length           { length $_[0]->{'prefix'}                       }


sub group_code               {   $_[0]->{'group_code'}                        }


sub group                    {   $_[0]->_group_data( $_[0]->group_code )->[0] }

sub _group_code_length   { 
	length(
		defined $_[0]->{'group_code'} ? $_[0]->{'group_code'} : ''    
		);
	}


sub publisher_code           {   $_[0]->{'publisher_code'}                    }
sub _publisher_code_length   { 
	length(
		defined $_[0]->{'publisher_code'} ? $_[0]->{'publisher_code'} : ''    
		);
	}


sub article_code             {   $_[0]->{'article_code'}                      }


sub checksum                 {   $_[0]->{'checksum'}                          }
sub _checksum_pos            { length( $_[0]->isbn ) - 1                      }



sub is_valid_checksum
	{
	my $self = shift;
	
	cluck "is_valid_checksum: Didn't get object!" unless ref $self;
	
	return GOOD_ISBN if $self->checksum eq $self->_checksum;

	return BAD_CHECKSUM;
	}


sub fix_checksum
	{
	my $self = shift;

	my $last_char = substr($self->isbn, $self->_checksum_pos, 1);
	my $checksum = $self->_checksum;

	my $isbn = $self->isbn;
	substr($isbn, $self->_checksum_pos, 1) = $checksum;

	$self->_set_isbn( $isbn );
	$self->_set_checksum( $checksum );

	$self->_check_validity;

	return 0 if $last_char eq $checksum;
	return 1;
	}



sub as_string
	{
	my $self      = shift;
	my $array_ref = shift;

	#this allows one to override the positions settings from the
	#constructor
	$array_ref = $self->_hyphen_positions unless ref $array_ref eq  ref [];

#	print STDERR Data::Dumper->Dump( [$array_ref], [qw(array_ref)] );
#	print STDERR Data::Dumper->Dump( [$self], [qw(self)] );
	
	return unless $self->is_valid eq GOOD_ISBN;
	my $isbn = $self->isbn;

	foreach my $position ( sort { $b <=> $a } @$array_ref )
		{
		next if $position > 12 or $position < 1;
		substr($isbn, $position, 0) = '-';
		}

	return $isbn;
	}


sub as_isbn10 
	{   
	croak "as_isbn10() must be implemented in Business::ISBN subclass" 
	}


sub as_isbn13 
	{   
	croak "as_isbn13() must be implemented in Business::ISBN subclass" 
	}


sub xisbn
	{
	my $self = shift;

	my $data = $self->_get_xisbn;
	$data =~ tr/x/X/;

	my @isbns = $data =~ m|<isbn>(.*?)</isbn>|ig;
	shift @isbns;
	wantarray ? @isbns : \@isbns;
	}

sub _get_xisbn
	{
	my $self = shift;

	eval "use LWP::Simple";
	if( $@ ) { carp "You need LWP::Simple to use xisbn()"; return; }

	my $data = LWP::Simple::get( $self->_xisbn_url );

	carp "Could not fetch xISBN data" unless defined $data;

	return $data;
	}

sub _xisbn_url
	{
	my $self = shift;
	my $isbn = $self->as_string([]);

	return "http://labs.oclc.org/xisbn/$isbn";
	}


sub png_barcode
	{
	my $self = shift;

	my $ean = $self->as_isbn13->as_string([]);

	eval "use GD::Barcode::EAN13";
	if( $@ )
		{
		carp "Need GD::Barcode::EAN13 to use png_barcode!";
		return;
		}

	my $image = GD::Barcode::EAN13->new($ean)->plot->png;
	
	return $image;
	}
	

sub _set_isbn           {   $_[0]->{'isbn'}           = $_[1];   }

sub _set_is_valid       {   $_[0]->{'valid'}          = $_[1];   }

sub _set_prefix              
	{   
	croak "_set_prefix() must be implemented in Business::ISBN subclass" 
	}

sub _set_group_code     {   $_[0]->{'group_code'}     = $_[1];   }

sub _set_group_code_string     {   $_[0]->{'group_code_string'}     = $_[1];   }

sub _set_publisher_code {   $_[0]->{'publisher_code'} = $_[1];   }

sub _set_publisher_code_string {   $_[0]->{'publisher_code_string'} = $_[1];   }

sub _set_article_code   {   $_[0]->{'article_code'}   = $_[1];   }

sub _set_checksum       {   $_[0]->{'checksum'}       = $_[1];   }

sub _set_type           
	{ 
	croak "_set_type() must be implemented in Business::ISBN subclass" 
	}

	
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
# # internal methods.  you don't get to use this one.
sub _common_format
	{
	#we want uppercase X's
	my $data = uc shift;

	#get rid of everything except decimal digits and X
	$data =~ s/[^0-9X]//g;

	return $1 if $data =~ m/
	        	        \A   	         #anchor at start
	        	        (
	        		        	(?:\d\d\d)?
								\d{9}[0-9X]
						)
	        	        \z	             #anchor at end
	                  	                  /x;

	return;
	}

sub _init
	{
	my $self = shift;
	my $common_data = shift;
	
	my $class = ref $self =~ m/.*::(.*)/g;
	
	$self->_set_type;
	$self->_set_isbn( $common_data );

	# we don't know if we have a valid group code yet
	# so let's assume that we don't
	$self->_set_is_valid( INVALID_GROUP_CODE );
	}

{
my @methods = (
	[ qw( prefix         ), INVALID_PREFIX         ],
	[ qw( group_code     ), INVALID_GROUP_CODE     ],
	[ qw( publisher_code ), INVALID_PUBLISHER_CODE ],
	[ qw( article_code   ), BAD_ISBN               ],
	[ qw( checksum       ), BAD_CHECKSUM           ],
	);
	
sub _parse_isbn
	{
	my $self = shift;
	
	foreach my $pair ( @methods )
		{
		my( $method, $error_code ) = @$pair;

		my $parser = "_parse_$method";
		my $result = $self->$parser;
		
		unless( defined $result )
			{
			$self->_set_is_valid( $error_code );
			#print STDERR "Got bad result for $method [$$self{isbn}]\n";
			return;
			}
			
		$method = "_set_$method";
		$self->$method( $result );
		}
	
	$self->_set_is_valid( $self->is_valid_checksum );
	
	return $self;
	}
}

sub _parse_group_code
	{
	my $self = shift;
	
	my $trial;  # try this to see what we get
	my $group_code_length = 0;

	my $count = 1;
	
	GROUP_CODE:
	while( defined( $trial= substr($self->isbn, $self->_prefix_length, $count++) ) )
		{
		if( defined $self->_group_data( $trial ) )
			{
			return $trial;
			last GROUP_CODE;
			}

		# if we've past the point of finding a group
		# code we're pretty much stuffed.
		return if $count > $self->_max_group_code_length;
		}
	
	return; #failed if I got this far
	}

sub _parse_publisher_code
	{
	my $self = shift;
	
	my $pairs = $self->_publisher_ranges;

	# get the longest possible publisher code
	# I'll try substrs of this to get the real one
	my $longest = substr(
		$self->isbn, 
		$self->_prefix_length + $self->_group_code_length,
		$self->_max_publisher_code_length,
		);
	
	#print STDERR "Trying to parse publisher: longest [$longest]\n";
	while( @$pairs )
		{
		my $lower  = shift @$pairs;
		my $upper  = shift @$pairs;
		
		my $trial  = substr( $longest, 0, length $lower ); 
		#print STDERR "Trying [$trial] with $lower <-> $upper [$$self{isbn}]\n";
		
		# this has to be a sring comparison because there are
		# possibly leading 0s
		if( $trial ge $lower and $trial le $upper )
			{
			#print STDERR "Returning $trial\n";
			return $trial;
			}
		
		}
		
	return; #failed if I got this far	
	}
	
sub _parse_article_code
	{
	my $self = shift;
	
	my $head = $self->_prefix_length + 
		$self->_group_code_length + 
		$self->_publisher_code_length;
	my $length = length( $self->isbn ) - $head - 1;
	
	substr( $self->isbn, $head, $length );
	}
	
sub _parse_checksum
	{
	my $self = shift;
	
	substr( $self->isbn, -1, 1 );
	}

sub _check_validity
	{
	my $self = shift;

	if( $self->is_valid_checksum  eq GOOD_ISBN and
		defined $self->group_code and 
		defined $self->publisher_code and
		defined $self->prefix
		)
	    {
	    $self->_set_is_valid( GOOD_ISBN );
	    }
	else
		{
		$self->_set_is_valid( INVALID_PUBLISHER_CODE )
			unless defined $self->publisher_code;
		$self->_set_is_valid( INVALID_GROUP_CODE )
			unless defined $self->group_code;
		$self->_set_is_valid( INVALID_PREFIX )
			 unless defined $self->prefix;
		$self->_set_is_valid( GOOD_ISBN )
			 unless $self->is_valid_checksum ne GOOD_ISBN;
		}
	}

sub _hyphen_positions        
	{ 
	croak "hyphen_positions() must be implemented in Business::ISBN subclass" 
	}


1;

__END__