1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
%% @author Guido Günther <agx@sigxcpu.org>
%% @copyright 2013 godiug.net
%%
%% This library is free software; you can redistribute it and/or
%% modify it under the terms of the GNU Lesser General Public
%% License as published by the Free Software Foundation; either
%% version 3 of the License, or (at your option) any later version.
%%
%% This library is distributed in the hope that it will be useful,
%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%% Lesser General Public License for more details.
%%
%% You should have received a copy of the GNU Lesser General Public
%% License along with this library. If not, see
%% <http://www.gnu.org/licenses/>.
%%
%% @doc Simple v4 uuid generator
-module(guid).
-export([v4/0,
v4string/0,
unparse/1,
version/1]).
%% @doc generate a version 4 uuid as bin
v4() ->
<< D1:32, D2:16, D3:16, D4:64 >> = crypto:rand_bytes(16),
<< D1:32, D2:16, 4:4, D3:12, D4:64 >>.
%% @doc generate a version 4 uuid as string
v4string() ->
unparse(v4()).
%% @doc convert a uuid from bin to string
unparse(UUID) ->
lists:flatten(
io_lib:format("~8.16.0b-"
"~4.16.0b-"
"~4.16.0b-"
"~2.16.0b~2.16.0b-"
"~12.16.0b", parts(UUID))).
%% @doc get a uuid's version number
version(<< _:48, Version:4, _:76 >>) ->
Version.
%% @private
% Return the parts of the uuid as per rfc4122:
% time_low (32), time_mid (16), time_hi_and_version (16)
% clock_seq_hi_and_reseved (8), clock_seq_low(8), node (48)
parts(<< TL:32, TM:16, THV:16, CSHR:8, CSL:8, N:48 >>) ->
[TL, TM, THV, CSHR, CSL, N].
|
