What module/library do you use to generate uuid?
+3
A:
from http://github.com/travis/erlang-uuid
-module(uuid).
-export([v4/0, to_string/1, get_parts/1]).
-import(random).
v4() ->
v4(random:uniform(math:pow(2, 48)) - 1, random:uniform(math:pow(2, 12)) - 1, random:uniform(math:pow(2, 32)) - 1, random:uniform(math:pow(2, 30)) - 1).
v4(R1, R2, R3, R4) ->
<<R1:48, 4:4, R2:12, 2:2, R3:32, R4: 30>>.
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))).
get_parts(<<TL:32, TM:16, THV:16, CSR:8, CSL:8, N:48>>) ->
[TL, TM, THV, CSR, CSL, N].
Tzury Bar Yochay
2009-11-01 13:52:20
I cannot execute v4():2> uuid:v4().** exception error: no function clause matching random:uniform(281474976710656.0) in function uuid:v4/0
sinnus
2009-11-01 14:16:55
filed a bug for you ;-)http://github.com/travis/erlang-uuid/issues/#issue/1
Tzury Bar Yochay
2009-11-01 14:56:56
There is not much point in recalculating math:pow(2, 48) all the time anyway, it could simply be replaced with 16#FFFFFFFFFFFF. The others similarly.
Zed
2009-11-01 17:40:52
@sinnus check out this commit, this was speedy indeed http://github.com/travis/erlang-uuid/issues/#issue/1
Tzury Bar Yochay
2009-11-02 06:09:08
Thank you! But I have found another solution from couch_db.
sinnus
2009-11-02 06:36:34
would be nice if you post it here since this page tops google search for "erlang uuid"
Tzury Bar Yochay
2009-11-02 08:52:37
Erlang uuid generator from couchdb: http://svn.apache.org/viewvc/couchdb/trunk/src/couchdb/couch_uuids.erl
sinnus
2009-11-02 10:37:27
Why do you import random if you use random:uniform? You don't need to do that in Erlang.
I GIVE TERRIBLE ADVICE
2009-11-05 19:59:10
+1
A:
Why did you use round(math:pow(2, 48))? I think that 1 bsl 48 will work more quickly and code will not lose understanding.
razumyan
2009-11-02 08:05:02
+3
A:
Uuid generator from couchdb: http://svn.apache.org/viewvc/couchdb/trunk/src/couchdb/couch%5Fuuids.erl
sinnus
2009-11-03 06:25:13