Business::ISBN(3)

NAME
Business::ISBN - work with International Standard Book Numbers

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

The data come from Business::ISBN::Data, which means you can update the data separately from the code. Also, you can use Business::ISBN::Data with whatever RangeMessage.xml you like if you have updated data. See that module for details.

  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->error" to something other than "GOOD_ISBN". An object is still returned and it is up to the program to check the "error" method for one of five values or one of the "error_*" methods to check for a particular error. 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);

    As of version 2.010_01, you can get this text from "error_text" so you don't have to import anything.

    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.

error_is_bad_group
error_is_bad_publisher
error_is_article_out_of_range
error_is_bad_checksum
    Returns true if the ISBN error is that type.

error_text
    Returns a text version of the 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.

article_code_length
    Returns the article code length for the ISBN.

article_code_min
    Returns the minimum article code length for the publisher code.

article_code_max
    Returns the max article code length for the publisher code.

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.

increment
    Returns the next "Business::ISBN" by incrementing the article code of the specified ISBN (object or scalar).

    Returns undef, if the parameter is invalid or equals the maximum possible ISBN for the publisher.

            $isbn = Business::ISBN->new('1565922573');  # 1-56592-257-3
            $next_isbn = $isbn->increment;              # 1-56592-258-1

    If the next article code would exceed the maximum possible article code (such as incrementing 999 to 1000), this returns ARTICLE_CODE_OUT_OF_RANGE as the error.

decrement
    Returns the previous "Business::ISBN" by decrementing the article code of the specified ISBN (object or scalar).

    Returns undef, if the parameter is invalid or equals the minimum possible ISBN for the publisher.

            $isbn = Business::ISBN->new('1565922573');  # 1-56592-257-3
            $prev_isbn = $isbn->decrement;              # 1-56592-256-5

    If the next article code would exceed the maximum possible article code (such as incrementing 000 to -1), this returns ARTICLE_CODE_OUT_OF_RANGE as the error.

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

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

SOURCE AVAILABILITY
This source is in Github:

    https://github.com/briandfoy/business-isbn

AUTHOR
brian d foy "<briandfoy@pobox.com>"

COPYRIGHT AND LICENSE
Copyright © 2001-2026, brian d foy <briandfoy@pobox.com>. All rights reserved.

This module is licensed under the Artistic License 2.0. See the LICENSE file in the distribution, or https://opensource.org/licenses/Artistic-2.0

CREDITS
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.

Markus Spann "<markus_spann@gmx.de>" added "increment" and "decrement".