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Manual Reference Pages  -  DATA::UUID (3)

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NAME

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

CONTENTS

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)
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