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.\" ========================================================================
.\"
.IX Title "UUID 3"
.TH UUID 3 "2020-04-12" "perl v5.26.3" "User Contributed Perl Documentation"
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.\" way too many mistakes in technical documents.
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.SH "NAME"
Data::UUID \- Globally/Universally Unique Identifiers (GUIDs/UUIDs)
.SH "SEE INSTEAD?"
.IX Header "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.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&  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 );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This module provides a framework for generating v3 UUIDs (Universally Unique
Identifiers, also known as GUIDs (Globally Unique Identifiers). A \s-1UUID\s0 is 128
bits long, and is guaranteed to be different from all other UUIDs/GUIDs
generated until 3400 \s-1CE.\s0
.PP
UUIDs were originally used in the Network Computing System (\s-1NCS\s0) and later in
the Open Software Foundation's (\s-1OSF\s0) Distributed Computing Environment.
Currently many different technologies rely on UUIDs to provide unique identity
for various software components. Microsoft \s-1COM/DCOM\s0 for instance, uses GUIDs
very extensively to uniquely identify classes, applications and components
across network-connected systems.
.PP
The algorithm for \s-1UUID\s0 generation, used by this extension, is described in the
Internet Draft \*(L"UUIDs and GUIDs\*(R" by Paul J. Leach and Rich Salz.  (See \s-1RFC
4122.\s0)  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.
.PP
This modules provides several methods to create a \s-1UUID.\s0  In all methods, \f(CW\*(C`<namespace>\*(C'\fR is a \s-1UUID\s0 and \f(CW\*(C`<name>\*(C'\fR is a free form string.
.PP
.Vb 3
\&   # 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>);
\&
\&   Conversely, 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>);
.Ve
.PP
Examples:
.PP
.Vb 1
\&   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");
.Ve
.SS "\s-1EXPORT\s0"
.IX Subsection "EXPORT"
The module allows exporting of several standard namespace UUIDs:
.IP "NameSpace_DNS" 4
.IX Item "NameSpace_DNS"
.PD 0
.IP "NameSpace_URL" 4
.IX Item "NameSpace_URL"
.IP "NameSpace_OID" 4
.IX Item "NameSpace_OID"
.IP "NameSpace_X500" 4
.IX Item "NameSpace_X500"
.PD
.SH "AUTHOR"
.IX Header "AUTHOR"
Alexander Golomshtok <agolomsh@cpan.org>
.SH "SEE ALSO"
.IX Header "SEE ALSO"
The Internet Draft \*(L"UUIDs and GUIDs\*(R" by Paul J. Leach and Rich Salz (\s-1RFC 4122\s0)