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xmpp.chapril.org-ejabberd/src/randoms.erl

56 lines
1.6 KiB
Erlang

%%%----------------------------------------------------------------------
%%% File : randoms.erl
%%% Author : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : Random generation number wrapper
%%% Created : 13 Dec 2002 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2017 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program 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
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License along
%%% with this program; if not, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------
-module(randoms).
-author('alexey@process-one.net').
-export([get_string/0, uniform/0, uniform/1, bytes/1]).
-export([start/0]).
-define(THRESHOLD, 16#10000000000000000).
start() ->
ok.
get_string() ->
R = crypto:rand_uniform(0, ?THRESHOLD),
integer_to_binary(R).
uniform() ->
crypto:rand_uniform(0, ?THRESHOLD)/?THRESHOLD.
uniform(N) ->
crypto:rand_uniform(1, N+1).
-ifdef(STRONG_RAND_BYTES).
bytes(N) ->
crypto:strong_rand_bytes(N).
-else.
bytes(N) ->
crypto:rand_bytes(N).
-endif.