NAME¶
Data::UUID::LibUUID - uuid.h based UUID generation (versions 2 and 4 depending
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 on
debian, 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. They
reveal 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 high
quality 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. This works 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 but also 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
hassle down to a minimum. DCE is UUID version two specification.
- ascending_ident
- Creates a lexically ascending identifier containing a UUID,
high resolution timestamp, and a counter.
This is not a UUID (it's longer), but if you can store variable length
identifier (and exposing the system clock is not an issue) they can be
used to create an identifier that is both universally unique, and
lexically increasing.
Note that while the identifiers are universally unique, there is no
universal ordering (that would require synchronization), so identifiers
generated on different machines or even different process/thread could
have IDs which interleave.
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.