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-rw-r--r--lib/stdlib/src/rand.erl36
1 files changed, 20 insertions, 16 deletions
diff --git a/lib/stdlib/src/rand.erl b/lib/stdlib/src/rand.erl
index 1f457b9e0e..3ff7aaf15f 100644
--- a/lib/stdlib/src/rand.erl
+++ b/lib/stdlib/src/rand.erl
@@ -45,20 +45,22 @@
%% =====================================================================
%% This depends on the algorithm handler function
--type alg_seed() :: exs64_state() | exsplus_state() | exs1024_state().
+-type alg_seed() :: 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]).
+ max := integer() | infinity,
+ next := fun((alg_seed()) -> {uint64(), alg_seed()}),
+ 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_seed()}.
+-type builtin_alg() :: exs64 | exsplus | exs1024.
+-type alg() :: builtin_alg() | term().
+-type export_state() :: {alg(), alg_seed()}.
+-export_type([builtin_alg/0, alg/0, alg_handler/0, alg_seed/0, state/0, export_state/0]).
%% =====================================================================
%% API
@@ -81,15 +83,17 @@ 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().
+-spec seed_s(AlgOrStateOrExpState::builtin_alg() | state() | export_state()) -> state().
seed_s(Alg) when is_atom(Alg) ->
seed_s(Alg, {erlang:phash2([{node(),self()}]),
erlang:system_time(),
erlang:unique_integer()});
+seed_s({AlgHandler, _Seed} = State) when is_map(AlgHandler) ->
+ State;
seed_s({Alg0, Seed}) ->
{Alg,_SeedFun} = mk_alg(Alg0),
{Alg, Seed}.
@@ -97,11 +101,11 @@ seed_s({Alg0, Seed}) ->
%% 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(), {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(), {integer(), integer(), integer()}) -> state().
seed_s(Alg0, S0 = {_, _, _}) ->
{Alg, Seed} = mk_alg(Alg0),
AS = Seed(S0),