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-rw-r--r--erts/emulator/test/nif_SUITE.erl47
1 files changed, 44 insertions, 3 deletions
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index 9127a5eae9..e177fa4963 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -57,6 +57,7 @@
nif_term_to_binary/1, nif_binary_to_term/1,
nif_port_command/1,
nif_snprintf/1,
+ nif_internal_hash/1,
nif_phash2/1
]).
@@ -92,6 +93,7 @@ all() ->
nif_term_to_binary, nif_binary_to_term,
nif_port_command,
nif_snprintf,
+ nif_internal_hash,
nif_phash2].
groups() ->
@@ -2612,15 +2614,54 @@ nif_snprintf(Config) ->
<<"{{hello,world,-33},",0>> = format_term_nif(20,{{hello,world, -33}, 3.14, self()}),
ok.
+nif_internal_hash(Config) ->
+ ensure_lib_loaded(Config),
+ Terms =
+ [random_term() || _ <- lists:seq(1, 5000)],
+
+ % Unlike the phash2 hash, in this case we
+ % have nothing to compare to, so let's try
+ % and at least make sure the distribution
+ % isn't outright wrong, statistical nuances
+ % aside.
+
+ OnesPerBit =
+ lists:foldl(
+ fun (Term, Acc) ->
+ NifHashValue = hash_nif(internal, Term),
+ lists:foldl(
+ fun (BitIndex, AccB) ->
+ BitValue = (NifHashValue band (1 bsl BitIndex)) bsr BitIndex,
+ dict:update_counter(BitIndex, BitValue, AccB)
+ end,
+ Acc,
+ lists:seq(0, 31))
+ end,
+ dict:new(),
+ Terms),
+
+ ExpectedNrOfOnes = length(Terms) div 2,
+ dict:fold(
+ fun (BitIndex, NrOfOnes, Acc) ->
+ RelativeDeviation = abs(NrOfOnes - ExpectedNrOfOnes) / ExpectedNrOfOnes,
+ (RelativeDeviation < 0.10
+ orelse ct:fail("Unreasonable deviation on number of set bits (i=~p): "
+ "expected ~p, got ~p (relative dev. ~.3f)",
+ [BitIndex, ExpectedNrOfOnes, NrOfOnes, RelativeDeviation])),
+ Acc
+ end,
+ ok,
+ OnesPerBit).
+
nif_phash2(Config) ->
ensure_lib_loaded(Config),
Terms =
- [random_term() || _ <- lists:seq(1, 1000)],
+ [random_term() || _ <- lists:seq(1, 5000)],
lists:foreach(
fun (Term) ->
HashValue = erlang:phash2(Term),
- NifHashValue = phash2_nif(Term),
+ NifHashValue = hash_nif(phash2, Term),
(HashValue =:= NifHashValue
orelse ct:fail("Expected: ~p\nActual: ~p",
[HashValue, NifHashValue]))
@@ -2673,7 +2714,7 @@ type_test() -> ?nif_stub.
tuple_2_list(_) -> ?nif_stub.
is_identical(_,_) -> ?nif_stub.
compare(_,_) -> ?nif_stub.
-phash2_nif(_) -> ?nif_stub.
+hash_nif(_, _) -> ?nif_stub.
many_args_100(_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_) -> ?nif_stub.
clone_bin(_) -> ?nif_stub.
make_sub_bin(_,_,_) -> ?nif_stub.