UUID

NAME

Data::UUID − Globally/Universally Unique Identifiers (GUIDs/UUIDs)

SEE INSTEAD?

The module Data::GUID provides another interface for generating GUIDs. Right now, it relies on Data::UUID, but it may not in the future. Its interface may be just a little more straightforward for the average Perl programer.

SYNOPSIS

use Data::UUID;
$ug = Data::UUID−>new;
$uuid1 = $ug−>create();
$uuid2 = $ug−>create_from_name(<namespace>, <name>);
$res = $ug−>compare($uuid1, $uuid2);
$str = $ug−>to_string( $uuid );
$uuid = $ug−>from_string( $str );

DESCRIPTION

This module provides a framework for generating v3 UUIDs (Universally Unique Identifiers, also known as GUIDs (Globally Unique Identifiers). A UUID is 128 bits long, and is guaranteed to be different from all other UUIDs/GUIDs generated until 3400 CE.

UUIDs were originally used in the Network Computing System ( NCS ) and later in the Open Software Foundation’s ( OSF ) Distributed Computing Environment. Currently many different technologies rely on UUIDs to provide unique identity for various software components. Microsoft COM/DCOM for instance, uses GUIDs very extensively to uniquely identify classes, applications and components across network-connected systems.

The algorithm for UUID generation, used by this extension, is described in the Internet Draft "UUIDs and GUIDs" by Paul J. Leach and Rich Salz. (See RFC 4122. ) It provides reasonably efficient and reliable framework for generating UUIDs and supports fairly high allocation rates -- 10 million per second per machine -- and therefore is suitable for identifying both extremely short-lived and very persistent objects on a given system as well as across the network.

This modules provides several methods to create a UUID. In all methods, "<namespace>" is a UUID and "<name>" is a free form string.

# creates binary (16 byte long binary value) UUID.
$ug−>create();
$ug−>create_bin();
# creates binary (16−byte long binary value) UUID based on particular
# namespace and name string.
$ug−>create_from_name(<namespace>, <name>);
$ug−>create_from_name_bin(<namespace>, <name>);
# creates UUID string, using conventional UUID string format,
# such as: 4162F712−1DD2−11B2−B17E−C09EFE1DC403
# Note that digits A−F are capitalized, which is contrary to rfc4122
$ug−>create_str();
$ug−>create_from_name_str(<namespace>, <name>);
# creates UUID string as a hex string,
# such as: 0x4162F7121DD211B2B17EC09EFE1DC403
# Note that digits A−F are capitalized, which is contrary to rfc4122
$ug−>create_hex();
$ug−>create_from_name_hex(<namespace>, <name>);
# creates UUID string as a Base64−encoded string
$ug−>create_b64();
$ug−>create_from_name_b64(<namespace>, <name>);
Binary UUIDs can be converted to printable strings using following methods:
# convert to conventional string representation
$ug−>to_string(<uuid>);
# convert to hex string (using upper, rather than lower, case letters)
$ug−>to_hexstring(<uuid>);
# convert to Base64−encoded string
$ug−>to_b64string(<uuid>);
Conversly, string UUIDs can be converted back to binary form:
# recreate binary UUID from string
$ug−>from_string(<uuid>);
$ug−>from_hexstring(<uuid>);
# recreate binary UUID from Base64−encoded string
$ug−>from_b64string(<uuid>);
Finally, two binary UUIDs can be compared using the following method:
# returns −1, 0 or 1 depending on whether uuid1 less
# than, equals to, or greater than uuid2
$ug−>compare(<uuid1>, <uuid2>);

Examples:

use Data::UUID;
# this creates a new UUID in string form, based on the standard namespace
# UUID NameSpace_URL and name "www.mycompany.com"
$ug = Data::UUID−>new;
print $ug−>create_from_name_str(NameSpace_URL, "www.mycompany.com");

EXPORT
The module allows exporting of several standard namespace UUIDs:
NameSpace_DNS
NameSpace_URL
NameSpace_OID
NameSpace_X500

AUTHOR

Alexander Golomshtok <agolomsh@cpan.org>

SEE ALSO

The Internet Draft "UUIDs and GUIDs" by Paul J. Leach and Rich Salz ( RFC 4122 )