Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tree: 2fbe55b417
Fetching contributors…

Cannot retrieve contributors at this time

61 lines (55 sloc) 2.734 kb
% Copyright (c) 2008, Travis Vachon
% All rights reserved.
%
% Redistribution and use in source and binary forms, with or without
% modification, are permitted provided that the following conditions are
% met:
%
% * Redistributions of source code must retain the above copyright
% notice, this list of conditions and the following disclaimer.
%
% * Redistributions in binary form must reproduce the above copyright
% notice, this list of conditions and the following disclaimer in the
% documentation and/or other materials provided with the distribution.
%
% * Neither the name of the author nor the names of its contributors
% may be used to endorse or promote products derived from this
% software without specific prior written permission.
%
% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
% "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
% LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
% A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
% OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
% SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
% TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
% PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
% LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
% NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
% SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
%
-module(uuid).
-export([v4/0, to_string/1, get_parts/1, to_binary/1]).
-import(random).
% Generates a random binary UUID.
v4() ->
random:seed(now()),
v4(random:uniform(round(math:pow(2, 48))) - 1, random:uniform(round(math:pow(2, 12))) - 1, random:uniform(round(math:pow(2, 32))) - 1, random:uniform(round(math:pow(2, 30))) - 1).
v4(R1, R2, R3, R4) ->
<<R1:48, 4:4, R2:12, 2:2, R3:32, R4: 30>>.
% Returns a string representation of a binary UUID.
to_string(U) ->
lists:flatten(io_lib:format("~8.16.0b-~4.16.0b-~4.16.0b-~2.16.0b~2.16.0b-~12.16.0b", get_parts(U))).
% Returns the 32, 16, 16, 8, 8, 48 parts of a binary UUID.
get_parts(<<TL:32, TM:16, THV:16, CSR:8, CSL:8, N:48>>) ->
[TL, TM, THV, CSR, CSL, N].
% Converts a UUID string in the format of 550e8400-e29b-41d4-a716-446655440000
% (with or without the dashes) to binary.
to_binary(U)->
convert(lists:filter(fun(Elem) -> Elem /= $- end, U), []).
% Converts a list of pairs of hex characters (00-ff) to bytes.
convert([], Acc)->
list_to_binary(lists:reverse(Acc));
convert([X, Y | Tail], Acc)->
{ok, [Byte], _} = io_lib:fread("~16u", [X, Y]),
convert(Tail, [Byte | Acc]).
Jump to Line
Something went wrong with that request. Please try again.