mirror of
https://github.com/processone/ejabberd.git
synced 2024-12-22 17:28:25 +01:00
92 lines
2.7 KiB
Erlang
92 lines
2.7 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) 2002-2018 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, uniform/2, bytes/1,
|
|
round_robin/1, get_alphanum_string/1]).
|
|
|
|
-define(THRESHOLD, 16#10000000000000000).
|
|
|
|
-ifdef(RAND_UNIFORM).
|
|
get_string() ->
|
|
R = rand:uniform(?THRESHOLD),
|
|
integer_to_binary(R).
|
|
|
|
uniform() ->
|
|
rand:uniform().
|
|
|
|
uniform(N) ->
|
|
rand:uniform(N).
|
|
|
|
uniform(N, M) ->
|
|
rand:uniform(M-N+1) + N-1.
|
|
-else.
|
|
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).
|
|
|
|
uniform(N, M) ->
|
|
crypto:rand_uniform(N, M+1).
|
|
-endif.
|
|
|
|
-ifdef(STRONG_RAND_BYTES).
|
|
bytes(N) ->
|
|
crypto:strong_rand_bytes(N).
|
|
-else.
|
|
bytes(N) ->
|
|
crypto:rand_bytes(N).
|
|
-endif.
|
|
|
|
-spec round_robin(pos_integer()) -> non_neg_integer().
|
|
round_robin(N) ->
|
|
p1_time_compat:unique_integer([monotonic, positive]) rem N.
|
|
|
|
-spec get_alphanum_string(non_neg_integer()) -> binary().
|
|
get_alphanum_string(Length) ->
|
|
list_to_binary(get_alphanum_string([], Length)).
|
|
|
|
-spec get_alphanum_string(string(), non_neg_integer()) -> string().
|
|
get_alphanum_string(S, 0) -> S;
|
|
get_alphanum_string(S, N) ->
|
|
get_alphanum_string([make_rand_char() | S], N - 1).
|
|
|
|
-spec make_rand_char() -> char().
|
|
make_rand_char() ->
|
|
map_int_to_char(uniform(0, 61)).
|
|
|
|
-spec map_int_to_char(0..61) -> char().
|
|
map_int_to_char(N) when N =< 9 -> N + 48; % Digit.
|
|
map_int_to_char(N) when N =< 35 -> N + 55; % Upper-case character.
|
|
map_int_to_char(N) when N =< 61 -> N + 61. % Lower-case character.
|