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-rw-r--r--lib/stdlib/doc/src/rand.xml61
-rw-r--r--lib/stdlib/src/rand.erl88
-rw-r--r--lib/stdlib/test/rand_SUITE.erl33
3 files changed, 124 insertions, 58 deletions
diff --git a/lib/stdlib/doc/src/rand.xml b/lib/stdlib/doc/src/rand.xml
index 8745e16908..2ddf3021ac 100644
--- a/lib/stdlib/doc/src/rand.xml
+++ b/lib/stdlib/doc/src/rand.xml
@@ -120,27 +120,50 @@ S0 = rand:seed_s(exsplus),
{SND0, S2} = rand:normal_s(S1),</pre>
<note>
- <p>This random number generator is not cryptographically
- strong. If a strong cryptographic random number generator is
- needed, use one of functions in the
- <seealso marker="crypto:crypto"><c>crypto</c></seealso>
- module, for example, <seealso marker="crypto:crypto">
- <c>crypto:strong_rand_bytes/1</c></seealso>.</p>
+ <p>The builtin random number generator algorithms are not
+ cryptographically strong. If a cryptographically strong
+ random number generator is needed, use something like
+ <seealso marker="crypto:crypto#rand_seed-0"><c>crypto:rand_seed/0</c></seealso>.
+ </p>
</note>
</description>
<datatypes>
<datatype>
+ <name name="builtin_alg"/>
+ </datatype>
+ <datatype>
<name name="alg"/>
</datatype>
<datatype>
+ <name name="alg_handler"/>
+ </datatype>
+ <datatype>
+ <name name="alg_state"/>
+ </datatype>
+ <datatype>
+ <name name="exs64_state"/>
+ <desc><p>Algorithm specific internal state</p></desc>
+ </datatype>
+ <datatype>
+ <name name="exsplus_state"/>
+ <desc><p>Algorithm specific internal state</p></desc>
+ </datatype>
+ <datatype>
+ <name name="exs1024_state"/>
+ <desc><p>Algorithm specific internal state</p></desc>
+ </datatype>
+ <datatype>
<name name="state"/>
<desc><p>Algorithm-dependent state.</p></desc>
</datatype>
<datatype>
<name name="export_state"/>
- <desc><p>Algorithm-dependent state that can be printed or saved to
- file.</p></desc>
+ <desc>
+ <p>
+ Algorithm-dependent state that can be printed or saved to file.
+ </p>
+ </desc>
</datatype>
</datatypes>
@@ -215,8 +238,11 @@ S0 = rand:seed_s(exsplus),
<fsummary>Seed random number generator.</fsummary>
<desc>
<marker id="seed-1"/>
- <p>Seeds random number generation with the specifed algorithm and
- time-dependent data if <anno>AlgOrExpState</anno> is an algorithm.</p>
+ <p>
+ Seeds random number generation with the specifed algorithm and
+ time-dependent data if <c><anno>AlgOrStateOrExpState</anno></c>
+ is an algorithm.
+ </p>
<p>Otherwise recreates the exported seed in the process dictionary,
and returns the state. See also
<seealso marker="#export_seed-0"><c>export_seed/0</c></seealso>.</p>
@@ -236,8 +262,11 @@ S0 = rand:seed_s(exsplus),
<name name="seed_s" arity="1"/>
<fsummary>Seed random number generator.</fsummary>
<desc>
- <p>Seeds random number generation with the specifed algorithm and
- time-dependent data if <anno>AlgOrExpState</anno> is an algorithm.</p>
+ <p>
+ Seeds random number generation with the specifed algorithm and
+ time-dependent data if <c><anno>AlgOrStateOrExpState</anno></c>
+ is an algorithm.
+ </p>
<p>Otherwise recreates the exported seed and returns the state.
See also <seealso marker="#export_seed-0">
<c>export_seed/0</c></seealso>.</p>
@@ -258,7 +287,7 @@ S0 = rand:seed_s(exsplus),
<fsummary>Return a random float.</fsummary>
<desc><marker id="uniform-0"/>
<p>Returns a random float uniformly distributed in the value
- range <c>0.0 &lt; <anno>X</anno> &lt; 1.0</c> and
+ range <c>0.0 =&lt; <anno>X</anno> &lt; 1.0</c> and
updates the state in the process dictionary.</p>
</desc>
</func>
@@ -269,7 +298,7 @@ S0 = rand:seed_s(exsplus),
<desc><marker id="uniform-1"/>
<p>Returns, for a specified integer <c><anno>N</anno> >= 1</c>,
a random integer uniformly distributed in the value range
- <c>1 &lt;= <anno>X</anno> &lt;= <anno>N</anno></c> and
+ <c>1 =&lt; <anno>X</anno> =&lt; <anno>N</anno></c> and
updates the state in the process dictionary.</p>
</desc>
</func>
@@ -279,7 +308,7 @@ S0 = rand:seed_s(exsplus),
<fsummary>Return a random float.</fsummary>
<desc>
<p>Returns, for a specified state, random float
- uniformly distributed in the value range <c>0.0 &lt;
+ uniformly distributed in the value range <c>0.0 =&lt;
<anno>X</anno> &lt; 1.0</c> and a new state.</p>
</desc>
</func>
@@ -290,7 +319,7 @@ S0 = rand:seed_s(exsplus),
<desc>
<p>Returns, for a specified integer <c><anno>N</anno> >= 1</c>
and a state, a random integer uniformly distributed in the value
- range <c>1 &lt;= <anno>X</anno> &lt;= <anno>N</anno></c> and a
+ range <c>1 =&lt; <anno>X</anno> =&lt; <anno>N</anno></c> and a
new state.</p>
</desc>
</func>
diff --git a/lib/stdlib/src/rand.erl b/lib/stdlib/src/rand.erl
index 1f457b9e0e..dfd102f9ef 100644
--- a/lib/stdlib/src/rand.erl
+++ b/lib/stdlib/src/rand.erl
@@ -45,20 +45,31 @@
%% =====================================================================
%% This depends on the algorithm handler function
--type alg_seed() :: exs64_state() | exsplus_state() | exs1024_state().
+-type alg_state() ::
+ exs64_state() | exsplus_state() | exs1024_state() | term().
+
%% This is the algorithm handler function within this module
--type alg_handler() :: #{type := alg(),
- max := integer(),
- next := fun(),
- uniform := fun(),
- uniform_n := fun(),
- jump := fun()}.
-
-%% Internal state
--opaque state() :: {alg_handler(), alg_seed()}.
--type alg() :: exs64 | exsplus | exs1024.
--opaque export_state() :: {alg(), alg_seed()}.
--export_type([alg/0, state/0, export_state/0]).
+-type alg_handler() ::
+ #{type := alg(),
+ max := integer() | infinity,
+ next :=
+ fun((alg_state()) -> {non_neg_integer(), alg_state()}),
+ uniform :=
+ fun((state()) -> {float(), state()}),
+ uniform_n :=
+ fun((pos_integer(), state()) -> {pos_integer(), state()}),
+ jump :=
+ fun((state()) -> state())}.
+
+%% Algorithm state
+-type state() :: {alg_handler(), alg_state()}.
+-type builtin_alg() :: exs64 | exsplus | exs1024.
+-type alg() :: builtin_alg() | atom().
+-type export_state() :: {alg(), alg_state()}.
+-export_type(
+ [builtin_alg/0, alg/0, alg_handler/0, alg_state/0,
+ state/0, export_state/0]).
+-export_type([exs64_state/0, exsplus_state/0, exs1024_state/0]).
%% =====================================================================
%% API
@@ -72,7 +83,7 @@ export_seed() ->
_ -> undefined
end.
--spec export_seed_s(state()) -> export_state().
+-spec export_seed_s(State :: state()) -> export_state().
export_seed_s({#{type:=Alg}, Seed}) -> {Alg, Seed}.
%% seed(Alg) seeds RNG with runtime dependent values
@@ -81,27 +92,37 @@ export_seed_s({#{type:=Alg}, Seed}) -> {Alg, Seed}.
%% seed({Alg,Seed}) setup RNG with a previously exported seed
%% and return the NEW state
--spec seed(AlgOrExpState::alg() | export_state()) -> state().
+-spec seed(
+ AlgOrStateOrExpState :: builtin_alg() | state() | export_state()) ->
+ state().
seed(Alg) ->
seed_put(seed_s(Alg)).
--spec seed_s(AlgOrExpState::alg() | export_state()) -> state().
-seed_s(Alg) when is_atom(Alg) ->
- seed_s(Alg, {erlang:phash2([{node(),self()}]),
- erlang:system_time(),
- erlang:unique_integer()});
+-spec seed_s(
+ AlgOrStateOrExpState :: builtin_alg() | state() | export_state()) ->
+ state().
+seed_s({AlgHandler, _Seed} = State) when is_map(AlgHandler) ->
+ State;
seed_s({Alg0, Seed}) ->
{Alg,_SeedFun} = mk_alg(Alg0),
- {Alg, Seed}.
+ {Alg, Seed};
+seed_s(Alg) ->
+ seed_s(Alg, {erlang:phash2([{node(),self()}]),
+ erlang:system_time(),
+ erlang:unique_integer()}).
%% seed/2: seeds RNG with the algorithm and given values
%% and returns the NEW state.
--spec seed(Alg :: alg(), {integer(), integer(), integer()}) -> state().
+-spec seed(
+ Alg :: builtin_alg(), Seed :: {integer(), integer(), integer()}) ->
+ state().
seed(Alg0, S0) ->
seed_put(seed_s(Alg0, S0)).
--spec seed_s(Alg :: alg(), {integer(), integer(), integer()}) -> state().
+-spec seed_s(
+ Alg :: builtin_alg(), Seed :: {integer(), integer(), integer()}) ->
+ state().
seed_s(Alg0, S0 = {_, _, _}) ->
{Alg, Seed} = mk_alg(Alg0),
AS = Seed(S0),
@@ -113,7 +134,7 @@ seed_s(Alg0, S0 = {_, _, _}) ->
%% uniform/0: returns a random float X where 0.0 < X < 1.0,
%% updating the state in the process dictionary.
--spec uniform() -> X::float().
+-spec uniform() -> X :: float().
uniform() ->
{X, Seed} = uniform_s(seed_get()),
_ = seed_put(Seed),
@@ -123,7 +144,7 @@ uniform() ->
%% uniform/1 returns a random integer X where 1 =< X =< N,
%% updating the state in the process dictionary.
--spec uniform(N :: pos_integer()) -> X::pos_integer().
+-spec uniform(N :: pos_integer()) -> X :: pos_integer().
uniform(N) ->
{X, Seed} = uniform_s(N, seed_get()),
_ = seed_put(Seed),
@@ -133,7 +154,7 @@ uniform(N) ->
%% returns a random float X where 0.0 < X < 1.0,
%% and a new state.
--spec uniform_s(state()) -> {X::float(), NewS :: state()}.
+-spec uniform_s(State :: state()) -> {X :: float(), NewState :: state()}.
uniform_s(State = {#{uniform:=Uniform}, _}) ->
Uniform(State).
@@ -141,7 +162,8 @@ uniform_s(State = {#{uniform:=Uniform}, _}) ->
%% uniform_s/2 returns a random integer X where 1 =< X =< N,
%% and a new state.
--spec uniform_s(N::pos_integer(), state()) -> {X::pos_integer(), NewS::state()}.
+-spec uniform_s(N :: pos_integer(), State :: state()) ->
+ {X :: pos_integer(), NewState :: state()}.
uniform_s(N, State = {#{uniform_n:=Uniform, max:=Max}, _})
when 0 < N, N =< Max ->
Uniform(N, State);
@@ -155,7 +177,7 @@ uniform_s(N, State0 = {#{uniform:=Uniform}, _})
%% after a large number of call defined for each algorithm.
%% The large number is algorithm dependent.
--spec jump(state()) -> NewS :: state().
+-spec jump(state()) -> NewState :: state().
jump(State = {#{jump:=Jump}, _}) ->
Jump(State).
@@ -164,7 +186,7 @@ jump(State = {#{jump:=Jump}, _}) ->
%% and write back the new value to the internal state,
%% then returns the new value.
--spec jump() -> NewS :: state().
+-spec jump() -> NewState :: state().
jump() ->
seed_put(jump(seed_get())).
@@ -182,7 +204,7 @@ normal() ->
%% The Ziggurat Method for generating random variables - Marsaglia and Tsang
%% Paper and reference code: http://www.jstatsoft.org/v05/i08/
--spec normal_s(state()) -> {float(), NewS :: state()}.
+-spec normal_s(State :: state()) -> {float(), NewState :: state()}.
normal_s(State0) ->
{Sign, R, State} = get_52(State0),
Idx = R band 16#FF,
@@ -245,7 +267,7 @@ mk_alg(exs1024) ->
%% Reference URL: http://xorshift.di.unimi.it/
%% =====================================================================
--type exs64_state() :: uint64().
+-opaque exs64_state() :: uint64().
exs64_seed({A1, A2, A3}) ->
{V1, _} = exs64_next(((A1 band ?UINT32MASK) * 4294967197 + 1)),
@@ -280,7 +302,7 @@ exs64_jump(_) ->
%% Modification of the original Xorshift128+ algorithm to 116
%% by Sebastiano Vigna, a lot of thanks for his help and work.
%% =====================================================================
--type exsplus_state() :: nonempty_improper_list(uint58(), uint58()).
+-opaque exsplus_state() :: nonempty_improper_list(uint58(), uint58()).
-dialyzer({no_improper_lists, exsplus_seed/1}).
@@ -349,7 +371,7 @@ exsplus_jump(S, [AS0|AS1], J, N) ->
%% Reference URL: http://xorshift.di.unimi.it/
%% =====================================================================
--type exs1024_state() :: {list(uint64()), list(uint64())}.
+-opaque exs1024_state() :: {list(uint64()), list(uint64())}.
exs1024_seed({A1, A2, A3}) ->
B1 = (((A1 band ?UINT21MASK) + 1) * 2097131) band ?UINT21MASK,
diff --git a/lib/stdlib/test/rand_SUITE.erl b/lib/stdlib/test/rand_SUITE.erl
index fe5eaccda5..098eefeb61 100644
--- a/lib/stdlib/test/rand_SUITE.erl
+++ b/lib/stdlib/test/rand_SUITE.erl
@@ -356,14 +356,23 @@ basic_normal_1(0, {#{type:=Alg}, _}, Sum, SumSq) ->
%% Test that the user can write algorithms.
plugin(Config) when is_list(Config) ->
- _ = lists:foldl(fun(_, S0) ->
- {V1, S1} = rand:uniform_s(10000, S0),
- true = is_integer(V1),
- {V2, S2} = rand:uniform_s(S1),
- true = is_float(V2),
- S2
- end, crypto_seed(), lists:seq(1, 200)),
- ok.
+ try crypto:strong_rand_bytes(1) of
+ <<_>> ->
+ _ = lists:foldl(
+ fun(_, S0) ->
+ {V1, S1} = rand:uniform_s(10000, S0),
+ true = is_integer(V1),
+ {V2, S2} = rand:uniform_s(S1),
+ true = is_float(V2),
+ S2
+ end, crypto_seed(), lists:seq(1, 200)),
+ ok
+ catch
+ error:low_entropy ->
+ {skip,low_entropy};
+ error:undef ->
+ {skip,no_crypto}
+ end.
%% Test implementation
crypto_seed() ->
@@ -397,7 +406,13 @@ crypto_uniform_n(N, State0) ->
measure(Suite) when is_atom(Suite) -> [];
measure(_Config) ->
ct:timetrap({minutes,15}), %% valgrind needs a lot of time
- Algos = [crypto64|algs()],
+ Algos =
+ try crypto:strong_rand_bytes(1) of
+ <<_>> -> [crypto64]
+ catch
+ error:low_entropy -> [];
+ error:undef -> []
+ end ++ algs(),
io:format("RNG uniform integer performance~n",[]),
_ = measure_1(random, fun(State) -> {int, random:uniform_s(10000, State)} end),
_ = [measure_1(Algo, fun(State) -> {int, rand:uniform_s(10000, State)} end) || Algo <- Algos],
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-09 10:34:00 +0000