NAME¶

Data::UUID::LibUUID - uuid.h based UUID generation (versions 2 and 4depending on platform)

SYNOPSIS¶

    use Data::UUID::LibUUID;
    my $uuid = new_uuid_string();

DESCRIPTION¶

This module provides bindings for libuuid shipped with e2fsprogs or uuid-dev ondebian, and also works with the system uuid.h on darwin.

EXPORTS¶

new_uuid_string $version

new_uuid_binary $version

Returns a new UUID in string (dash separated hex) or binary (16 octets) format.

$version can be either 2, or 4 and defaults to whatever the underlying implementation prefers.

Version 1 is timestamp/MAC based UUIDs, like Data::UUID provides. Theyreveal time and host information, so they may be considered a security risk.

Version 2 is described here<http://www.opengroup.org/onlinepubs/9696989899/chap5.htm#tagcjh_08_02_01_01>.It is similar to version 1 but considered more secure.

Version 4 is based just on random data. This is not guaranteed to be highquality random data, but usually is supposed to be.

On MacOS X "getpid" is called before UUID generation, to ensure UUIDs are unique accross forks. Behavior on other platforms may vary.

uuid_to_binary $str_or_bin

Converts a UUID from string or binary format to binary format.

Returns undef on a non UUID argument.

uuid_to_string $str_or_bin

Converts a UUID from string or binary format to string format.

Returns undef on a non UUID argument.

uuid_eq $str_or_bin, $str_or_bin

Checks if two UUIDs are equivalent. Returns true if they are, or false if they aren't.

Returns undef on non UUID arguments.

uuid_compare $str_or_bin, $str_or_bin

Returns -1, 0 or 1 depending on the lexicographical order of the UUID. Thisworks like the "cmp" builtin.

Returns undef on non UUID arguments.

new_dce_uuid_string

new_dce_uuid_binary

These two subroutines are a little hackish in that they take no arguments butalso do not validate the arguments, so they can be abused as methods:

    package MyFoo;
    use Data::UUID::LibUUID (
        new_dce_uuid_string => { -as "generate_uuid" },
    );
    sub yadda {
        my $self = shift;
        my $id = $self->generate_uuid;
    }
    

This allows the ID generation code to be subclassed, but still keeps the hassledown to a minimum. DCE is UUID version two specification.

ascending_ident

Creates a lexically ascending identifier containing a UUID, high resolutiontimestamp, and a counter.

This is not a UUID (it's longer), but if you can store variable lengthidentifier (and exposing the system clock is not an issue) they can be used tocreate an identifier that is both universally unique, and lexicallyincreasing.

Note that while the identifiers are universally unique, there is no universalordering (that would require synchronization), so identifiers generated ondifferent machines or even different process/thread could have IDs whichinterleave.

TODO¶

•

Consider bundling libuuid for when no system "uuid.h" exists.

SEE ALSO¶

Data::GUID, Data::UUID, UUID, <http://e2fsprogs.sourceforge.net/>

VERSION CONTROL¶

This module is maintained using Darcs. You can get the latest version from<http://nothingmuch.woobling.org/code>, and use "darcs send" to commit changes.

AUTHOR¶

Yuval Kogman <nothingmuch@woobling.org>

COPYRIGHT¶

    Copyright (c) 2008 Yuval Kogman. All rights reserved
    This program is free software; you can redistribute
    it and/or modify it under the same terms as Perl itself.