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-rw-r--r--lib/kernel/test/zlib_SUITE.erl351
1 files changed, 255 insertions, 96 deletions
diff --git a/lib/kernel/test/zlib_SUITE.erl b/lib/kernel/test/zlib_SUITE.erl
index 4b67fce9a8..efbbc805a0 100644
--- a/lib/kernel/test/zlib_SUITE.erl
+++ b/lib/kernel/test/zlib_SUITE.erl
@@ -21,6 +21,7 @@
-module(zlib_SUITE).
-include_lib("common_test/include/ct.hrl").
+-include_lib("common_test/include/ct_event.hrl").
-compile(export_all).
@@ -43,7 +44,7 @@
end
end()).
--define(BARG, {'EXIT',{badarg,[{zlib,_,_,_}|_]}}).
+-define(BARG, {'EXIT',{badarg,[{_,_,_,_}|_]}}).
-define(DATA_ERROR, {'EXIT',{data_error,[{zlib,_,_,_}|_]}}).
init_per_testcase(_Func, Config) ->
@@ -74,7 +75,8 @@ suite() ->
{timetrap,{minutes,1}}].
all() ->
- [{group, api}, {group, examples}, {group, func}, smp,
+ [{group, api}, {group, examples}, {group, func},
+ {group, bench}, smp,
otp_9981,
otp_7359].
@@ -84,14 +86,19 @@ groups() ->
api_deflateSetDictionary, api_deflateReset,
api_deflateParams, api_deflate, api_deflateEnd,
api_inflateInit, api_inflateSetDictionary, api_inflateGetDictionary,
- api_inflateSync, api_inflateReset, api_inflate, api_inflateChunk,
- api_inflateEnd, api_setBufsz, api_getBufsz, api_crc32,
- api_adler32, api_getQSize, api_un_compress, api_un_zip,
+ api_inflateReset, api_inflate2, api_inflate3, api_inflateChunk,
+ api_safeInflate, api_inflateEnd, api_crc32,
+ api_adler32, api_un_compress, api_un_zip,
api_g_un_zip]},
{examples, [], [intro]},
{func, [],
[zip_usage, gz_usage, gz_usage2, compress_usage,
- dictionary_usage, large_deflate, crc, adler]}].
+ dictionary_usage, large_deflate, crc, adler,
+ only_allow_owner, sub_heap_binaries]},
+ {bench,
+ [inflate_bench_zeroed, inflate_bench_rand,
+ deflate_bench_zeroed, deflate_bench_rand,
+ chunk_bench_zeroed, chunk_bench_rand]}].
init_per_suite(Config) ->
Config.
@@ -244,7 +251,7 @@ api_deflateEnd(Config) when is_list(Config) ->
Z1 = zlib:open(),
?m(ok, zlib:deflateInit(Z1, default)),
?m(ok, zlib:deflateEnd(Z1)),
- ?m({'EXIT', {einval,_}}, zlib:deflateEnd(Z1)), %% ??
+ ?m(?BARG, zlib:deflateEnd(Z1)),
?m(?BARG, zlib:deflateEnd(gurka)),
?m(ok, zlib:deflateInit(Z1, default)),
?m(B when is_list(B), zlib:deflate(Z1, <<"Kilroy was here">>)),
@@ -261,7 +268,7 @@ api_inflateInit(Config) when is_list(Config) ->
Z1 = zlib:open(),
?m(?BARG, zlib:inflateInit(gurka)),
?m(ok, zlib:inflateInit(Z1)),
- ?m({'EXIT',{einval,_}}, zlib:inflateInit(Z1, 15)), %% ??
+ ?m(?BARG, zlib:inflateInit(Z1, 15)),
lists:foreach(fun(Wbits) ->
Z11 = zlib:open(),
?m(ok, zlib:inflateInit(Z11,Wbits)),
@@ -291,12 +298,13 @@ api_inflateSetDictionary(Config) when is_list(Config) ->
%% Test inflateGetDictionary.
api_inflateGetDictionary(Config) when is_list(Config) ->
Z1 = zlib:open(),
+ zlib:inflateInit(Z1),
IsOperationSupported =
case catch zlib:inflateGetDictionary(Z1) of
- {'EXIT',{einval,_}} -> true;
- {'EXIT',{enotsup,_}} -> false
+ ?BARG -> false;
+ _ -> true
end,
- _ = zlib:close(Z1),
+ zlib:close(Z1),
api_inflateGetDictionary_if_supported(IsOperationSupported).
api_inflateGetDictionary_if_supported(false) ->
@@ -306,45 +314,42 @@ api_inflateGetDictionary_if_supported(true) ->
Z1 = zlib:open(),
?m(ok, zlib:deflateInit(Z1)),
Dict = <<"foobar barfoo foo bar far boo">>,
- ?m(_, zlib:deflateSetDictionary(Z1, Dict)),
+ Checksum = zlib:deflateSetDictionary(Z1, Dict),
Payload = <<"foobarbarbar">>,
Compressed = zlib:deflate(Z1, Payload, finish),
?m(ok, zlib:close(Z1)),
- % Decompress and test dictionary extraction
+ % Decompress and test dictionary extraction with inflate/2
Z2 = zlib:open(),
?m(ok, zlib:inflateInit(Z2)),
?m(<<>>, iolist_to_binary(zlib:inflateGetDictionary(Z2))),
?m({'EXIT',{stream_error,_}}, zlib:inflateSetDictionary(Z2, Dict)),
- ?m({'EXIT',{{need_dictionary,_},_}}, zlib:inflate(Z2, Compressed)),
+ ?m({'EXIT',{{need_dictionary,Checksum},_}}, zlib:inflate(Z2, Compressed)),
?m(ok, zlib:inflateSetDictionary(Z2, Dict)),
?m(Dict, iolist_to_binary(zlib:inflateGetDictionary(Z2))),
- ?m(Payload, iolist_to_binary(zlib:inflate(Z2, Compressed))),
+ Payload = iolist_to_binary(zlib:inflate(Z2, [])),
?m(ok, zlib:close(Z2)),
?m(?BARG, zlib:inflateSetDictionary(Z2, Dict)),
- ok.
-%% Test inflateSync.
-api_inflateSync(Config) when is_list(Config) ->
- {skip,"inflateSync/1 sucks"}.
-%% Z1 = zlib:open(),
-%% ?m(ok, zlib:deflateInit(Z1)),
-%% B1list0 = zlib:deflate(Z1, "gurkan gurra ger galna tunnor", full),
-%% B2 = zlib:deflate(Z1, "grodan boll", finish),
-%% io:format("~p\n", [B1list0]),
-%% io:format("~p\n", [B2]),
-%% ?m(ok, zlib:deflateEnd(Z1)),
-%% B1 = clobber(14, list_to_binary(B1list0)),
-%% Compressed = list_to_binary([B1,B2]),
-%% io:format("~p\n", [Compressed]),
-
-%% ?m(ok, zlib:inflateInit(Z1)),
-%% ?m(?BARG, zlib:inflateSync(gurka)),
-%% ?m({'EXIT',{data_error,_}}, zlib:inflate(Z1, Compressed)),
-%% ?m(ok, zlib:inflateSync(Z1)),
-%% Ubs = zlib:inflate(Z1, []),
-%% <<"grodan boll">> = list_to_binary(Ubs),
-%% ?m(ok, zlib:close(Z1)).
+ %% ... And do the same for inflate/3
+ Z3 = zlib:open(),
+ ?m(ok, zlib:inflateInit(Z3)),
+ ?m(<<>>, iolist_to_binary(zlib:inflateGetDictionary(Z3))),
+ ?m({'EXIT',{stream_error,_}}, zlib:inflateSetDictionary(Z3, Dict)),
+
+ {need_dictionary, Checksum, _Output = []} =
+ zlib:inflate(Z3, Compressed, [{exception_on_need_dict, false}]),
+
+ ?m(ok, zlib:inflateSetDictionary(Z3, Dict)),
+ ?m(Dict, iolist_to_binary(zlib:inflateGetDictionary(Z3))),
+
+ Payload = iolist_to_binary(
+ zlib:inflate(Z3, [], [{exception_on_need_dict, false}])),
+
+ ?m(ok, zlib:close(Z3)),
+ ?m(?BARG, zlib:inflateSetDictionary(Z3, Dict)),
+
+ ok.
clobber(N, Bin) when is_binary(Bin) ->
T = list_to_tuple(binary_to_list(Bin)),
@@ -362,8 +367,8 @@ api_inflateReset(Config) when is_list(Config) ->
?m(ok, zlib:inflateReset(Z1)),
?m(ok, zlib:close(Z1)).
-%% Test inflate.
-api_inflate(Config) when is_list(Config) ->
+%% Test inflate/2
+api_inflate2(Config) when is_list(Config) ->
Data = [<<1,2,2,3,3,3,4,4,4,4>>],
Compressed = zlib:compress(Data),
Z1 = zlib:open(),
@@ -375,12 +380,32 @@ api_inflate(Config) when is_list(Config) ->
?m(Data, zlib:inflate(Z1, Compressed)),
?m(?BARG, zlib:inflate(gurka, Compressed)),
?m(?BARG, zlib:inflate(Z1, 4384)),
- ?m(?BARG, zlib:inflate(Z1, [atom_list])),
+ ?m(?BARG, zlib:inflate(Z1, [atom_list])),
?m(ok, zlib:inflateEnd(Z1)),
?m(ok, zlib:inflateInit(Z1)),
?m({'EXIT',{data_error,_}}, zlib:inflate(Z1, <<2,1,2,1,2>>)),
?m(ok, zlib:close(Z1)).
+%% Test inflate/3; same as inflate/2 but with the default options inverted.
+api_inflate3(Config) when is_list(Config) ->
+ Data = [<<1,2,2,3,3,3,4,4,4,4>>],
+ Options = [{exception_on_need_dict, false}],
+ Compressed = zlib:compress(Data),
+ Z1 = zlib:open(),
+ ?m(ok, zlib:inflateInit(Z1)),
+ ?m([], zlib:inflate(Z1, <<>>, Options)),
+ ?m(Data, zlib:inflate(Z1, Compressed)),
+ ?m(ok, zlib:inflateEnd(Z1)),
+ ?m(ok, zlib:inflateInit(Z1)),
+ ?m(Data, zlib:inflate(Z1, Compressed, Options)),
+ ?m(?BARG, zlib:inflate(gurka, Compressed, Options)),
+ ?m(?BARG, zlib:inflate(Z1, 4384, Options)),
+ ?m(?BARG, zlib:inflate(Z1, [atom_list], Options)),
+ ?m(ok, zlib:inflateEnd(Z1)),
+ ?m(ok, zlib:inflateInit(Z1)),
+ ?m({'EXIT',{data_error,_}}, zlib:inflate(Z1, <<2,1,2,1,2>>, Options)),
+ ?m(ok, zlib:close(Z1)).
+
%% Test inflateChunk.
api_inflateChunk(Config) when is_list(Config) ->
ChunkSize = 1024,
@@ -388,71 +413,107 @@ api_inflateChunk(Config) when is_list(Config) ->
Part1 = binary:part(Data, 0, ChunkSize),
Part2 = binary:part(Data, ChunkSize, ChunkSize),
Part3 = binary:part(Data, ChunkSize * 2, ChunkSize),
+
Compressed = zlib:compress(Data),
Z1 = zlib:open(),
+
zlib:setBufSize(Z1, ChunkSize),
+
?m(ok, zlib:inflateInit(Z1)),
- ?m([], zlib:inflateChunk(Z1, <<>>)),
- ?m({more, Part1}, zlib:inflateChunk(Z1, Compressed)),
- ?m({more, Part2}, zlib:inflateChunk(Z1)),
- ?m(Part3, zlib:inflateChunk(Z1)),
- ?m(ok, zlib:inflateEnd(Z1)),
+ 0 = iolist_size(zlib:inflateChunk(Z1, <<>>)),
+
+ {more, Part1AsIOList} = zlib:inflateChunk(Z1, Compressed),
+ {more, Part2AsIOList} = zlib:inflateChunk(Z1),
+ {more, Part3AsIOList} = zlib:inflateChunk(Z1),
+ [] = zlib:inflateChunk(Z1),
+
+ ?m(Part1, iolist_to_binary(Part1AsIOList)),
+ ?m(Part2, iolist_to_binary(Part2AsIOList)),
+ ?m(Part3, iolist_to_binary(Part3AsIOList)),
+
+ ?m(ok, zlib:inflateEnd(Z1)),
?m(ok, zlib:inflateInit(Z1)),
- ?m({more, Part1}, zlib:inflateChunk(Z1, Compressed)),
+
+ ?m({more, Part1AsIOList}, zlib:inflateChunk(Z1, Compressed)),
?m(ok, zlib:inflateReset(Z1)),
- zlib:setBufSize(Z1, size(Data)),
- ?m(Data, zlib:inflateChunk(Z1, Compressed)),
- ?m(ok, zlib:inflateEnd(Z1)),
+ zlib:setBufSize(Z1, byte_size(Data) + 1),
+ DataAsIOList = zlib:inflateChunk(Z1, Compressed),
+ ?m(Data, iolist_to_binary(DataAsIOList)),
+
+ ?m(ok, zlib:inflateEnd(Z1)),
?m(ok, zlib:inflateInit(Z1)),
+
?m(?BARG, zlib:inflateChunk(gurka, Compressed)),
?m(?BARG, zlib:inflateChunk(Z1, 4384)),
+
+ ?m({'EXIT',{data_error,_}}, zlib:inflateEnd(Z1)),
+
+ ?m(ok, zlib:close(Z1)).
+
+%% Test safeInflate as a mirror of inflateChunk, but ignore the stuff about
+%% exact chunk sizes.
+api_safeInflate(Config) when is_list(Config) ->
+ Data = << <<(I rem 150)>> || I <- lists:seq(1, 20 bsl 10) >>,
+ Compressed = zlib:compress(Data),
+ Z1 = zlib:open(),
+
+ ?m(ok, zlib:inflateInit(Z1)),
+
+ SafeInflateLoop =
+ fun
+ Loop({continue, Chunk}, Output) ->
+ Loop(zlib:safeInflate(Z1, []), [Output, Chunk]);
+ Loop({finished, Chunk}, Output) ->
+ [Output, Chunk]
+ end,
+
+ Decompressed = SafeInflateLoop(zlib:safeInflate(Z1, Compressed), []),
+ Data = iolist_to_binary(Decompressed),
+
+ ?m(ok, zlib:inflateEnd(Z1)),
+ ?m(ok, zlib:inflateInit(Z1)),
+
+ {continue, Partial} = zlib:safeInflate(Z1, Compressed),
+ PBin = iolist_to_binary(Partial),
+ PSize = byte_size(PBin),
+ <<PBin:PSize/binary, Rest/binary>> = Data,
+
+ ?m(ok, zlib:inflateReset(Z1)),
+
+ {continue, Partial} = zlib:safeInflate(Z1, Compressed),
+ PBin = iolist_to_binary(Partial),
+ PSize = byte_size(PBin),
+ <<PBin:PSize/binary, Rest/binary>> = Data,
+
+ ?m(ok, zlib:inflateReset(Z1)),
+
+ SafeInflateLoop(zlib:safeInflate(Z1, Compressed), []),
+
+ ?m({'EXIT',{data_error,_}}, zlib:safeInflate(Z1, Compressed)),
+
+ ?m(ok, zlib:inflateReset(Z1)),
+ ?m(?BARG, zlib:safeInflate(gurka, Compressed)),
+ ?m(?BARG, zlib:safeInflate(Z1, 4384)),
?m({'EXIT',{data_error,_}}, zlib:inflateEnd(Z1)),
?m(ok, zlib:close(Z1)).
%% Test inflateEnd.
api_inflateEnd(Config) when is_list(Config) ->
Z1 = zlib:open(),
- ?m({'EXIT',{einval,_}}, zlib:inflateEnd(Z1)),
+ ?m(?BARG, zlib:inflateEnd(Z1)),
?m(ok, zlib:inflateInit(Z1)),
?m(?BARG, zlib:inflateEnd(gurka)),
?m({'EXIT',{data_error,_}}, zlib:inflateEnd(Z1)),
- ?m({'EXIT',{einval,_}}, zlib:inflateEnd(Z1)),
+ ?m(?BARG, zlib:inflateEnd(Z1)),
?m(ok, zlib:inflateInit(Z1)),
?m(B when is_list(B), zlib:inflate(Z1, zlib:compress("abc"))),
?m(ok, zlib:inflateEnd(Z1)),
?m(ok, zlib:close(Z1)).
-%% Test getBufsz.
-api_getBufsz(Config) when is_list(Config) ->
- Z1 = zlib:open(),
- ?m(Val when is_integer(Val), zlib:getBufSize(Z1)),
- ?m(?BARG, zlib:getBufSize(gurka)),
- ?m(ok, zlib:close(Z1)).
-
-%% Test setBufsz.
-api_setBufsz(Config) when is_list(Config) ->
- Z1 = zlib:open(),
- ?m(?BARG, zlib:setBufSize(Z1, gurka)),
- ?m(?BARG, zlib:setBufSize(gurka, 1232330)),
- Sz = ?m( Val when is_integer(Val), zlib:getBufSize(Z1)),
- ?m(ok, zlib:setBufSize(Z1, Sz*2)),
- DSz = Sz*2,
- ?m(DSz, zlib:getBufSize(Z1)),
- ?m(ok, zlib:close(Z1)).
-
-%%% Debug function ??
-%% Test getQSize.
-api_getQSize(Config) when is_list(Config) ->
- Z1 = zlib:open(),
- Q = ?m(Val when is_integer(Val), zlib:getQSize(Z1)),
- io:format("QSize ~p ~n", [Q]),
- ?m(?BARG, zlib:getQSize(gurka)),
- ?m(ok, zlib:close(Z1)).
-
%% Test crc32.
api_crc32(Config) when is_list(Config) ->
Z1 = zlib:open(),
@@ -594,24 +655,9 @@ intro(Config) when is_list(Config) ->
large_deflate(Config) when is_list(Config) ->
large_deflate_do().
large_deflate_do() ->
- Z = zlib:open(),
- Plain = rand_bytes(zlib:getBufSize(Z)*5),
- ok = zlib:deflateInit(Z),
- _ZlibHeader = zlib:deflate(Z, [], full),
- Deflated = zlib:deflate(Z, Plain, full),
- ?m(ok, zlib:close(Z)),
- ?m(Plain, zlib:unzip(list_to_binary([Deflated, 3, 0]))).
-
-rand_bytes(Sz) ->
- L = <<8,2,3,6,1,2,3,2,3,4,8,7,3,7,2,3,4,7,5,8,9,3>>,
- rand_bytes(erlang:md5(L),Sz).
-
-rand_bytes(Bin, Sz) when byte_size(Bin) >= Sz ->
- <<Res:Sz/binary, _/binary>> = Bin,
- Res;
-rand_bytes(Bin, Sz) ->
- rand_bytes(<<(erlang:md5(Bin))/binary, Bin/binary>>, Sz).
-
+ Plain = gen_determ_rand_bytes(64 bsl 10),
+ Deflated = zlib:zip(Plain),
+ ?m(Plain, zlib:unzip(Deflated)).
%% Test a standard compressed zip file.
zip_usage(Config) when is_list(Config) ->
@@ -869,10 +915,14 @@ dictionary_usage({run}) ->
%% Now uncompress.
Z2 = zlib:open(),
?m(ok, zlib:inflateInit(Z2)),
+
{'EXIT',{{need_dictionary,DictID},_}} = (catch zlib:inflate(Z2, Compressed)),
+
?m(ok, zlib:inflateSetDictionary(Z2, Dict)),
?m(ok, zlib:inflateSetDictionary(Z2, binary_to_list(Dict))),
+
Uncompressed = ?m(B when is_list(B), zlib:inflate(Z2, [])),
+
?m(ok, zlib:inflateEnd(Z2)),
?m(ok, zlib:close(Z2)),
?m(Data, list_to_binary(Uncompressed)).
@@ -882,6 +932,35 @@ split_bin(<<Part:1997/binary,Rest/binary>>, Acc) ->
split_bin(Last,Acc) ->
lists:reverse([Last|Acc]).
+only_allow_owner(Config) when is_list(Config) ->
+ Z = zlib:open(),
+
+ ?m(ok, zlib:inflateInit(Z)),
+ ?m(ok, zlib:inflateReset(Z)),
+
+ {Pid, Ref} = spawn_monitor(
+ fun() ->
+ ?m(?BARG, zlib:inflateReset(Z))
+ end),
+
+ receive
+ {'DOWN', Ref, process, Pid, _Reason} ->
+ ok
+ after 200 ->
+ ?error("Spawned worker timed out.", [])
+ end,
+
+ ?m(ok, zlib:inflateReset(Z)).
+
+sub_heap_binaries(Config) when is_list(Config) ->
+ Compressed = zlib:compress(<<"gurka">>),
+ ConfLen = erlang:length(Config),
+
+ HeapBin = <<ConfLen:8/integer, Compressed/binary>>,
+ <<_:8/integer, SubHeapBin/binary>> = HeapBin,
+
+ ?m(<<"gurka">>, zlib:uncompress(SubHeapBin)),
+ ok.
%% Check concurrent access to zlib driver.
smp(Config) ->
@@ -999,7 +1078,78 @@ otp_9981(Config) when is_list(Config) ->
Ports = lists:sort(erlang:ports()),
ok.
+-define(BENCH_SIZE, (16 bsl 20)).
+
+-define(DECOMPRESS_BENCH(Name, What, Data),
+ Name(Config) when is_list(Config) ->
+ Uncompressed = Data,
+ Compressed = zlib:compress(Uncompressed),
+ What(Compressed, byte_size(Uncompressed))).
+
+-define(COMPRESS_BENCH(Name, What, Data),
+ Name(Config) when is_list(Config) ->
+ Compressed = Data,
+ What(Compressed, byte_size(Compressed))).
+
+?DECOMPRESS_BENCH(inflate_bench_zeroed, throughput_bench_inflate,
+ <<0:(8 * ?BENCH_SIZE)>>).
+?DECOMPRESS_BENCH(inflate_bench_rand, throughput_bench_inflate,
+ gen_determ_rand_bytes(?BENCH_SIZE)).
+
+?DECOMPRESS_BENCH(chunk_bench_zeroed, throughput_bench_chunk,
+ <<0:(8 * ?BENCH_SIZE)>>).
+?DECOMPRESS_BENCH(chunk_bench_rand, throughput_bench_chunk,
+ gen_determ_rand_bytes(?BENCH_SIZE)).
+
+?COMPRESS_BENCH(deflate_bench_zeroed, throughput_bench_deflate,
+ <<0:(8 * ?BENCH_SIZE)>>).
+?COMPRESS_BENCH(deflate_bench_rand, throughput_bench_deflate,
+ gen_determ_rand_bytes(?BENCH_SIZE)).
+
+throughput_bench_inflate(Compressed, Size) ->
+ Z = zlib:open(),
+ zlib:inflateInit(Z),
+
+ submit_throughput_results(Size,
+ fun() ->
+ zlib:inflate(Z, Compressed)
+ end).
+
+throughput_bench_deflate(Uncompressed, Size) ->
+ Z = zlib:open(),
+ zlib:deflateInit(Z),
+
+ submit_throughput_results(Size,
+ fun() ->
+ zlib:deflate(Z, Uncompressed, finish)
+ end).
+
+throughput_bench_chunk(Compressed, Size) ->
+ Z = zlib:open(),
+ zlib:inflateInit(Z),
+
+ ChunkLoop =
+ fun
+ Loop({more, _}) -> Loop(zlib:inflateChunk(Z));
+ Loop(_) -> ok
+ end,
+
+ submit_throughput_results(Size,
+ fun() ->
+ ChunkLoop(zlib:inflateChunk(Z, Compressed))
+ end).
+
+submit_throughput_results(Size, Fun) ->
+ TimeTaken = measure_perf_counter(Fun, millisecond),
+
+ KBPS = trunc((Size bsr 10) / (TimeTaken / 1000)),
+ ct_event:notify(#event{ name = benchmark_data, data = [{value,KBPS}] }),
+ {comment, io_lib:format("~p ms, ~p KBPS", [TimeTaken, KBPS])}.
+measure_perf_counter(Fun, Unit) ->
+ Start = os:perf_counter(Unit),
+ Fun(),
+ os:perf_counter(Unit) - Start.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Helps with testing directly %%%%%%%%%%%%%
@@ -1039,3 +1189,12 @@ expand([H|T], Acc) ->
end;
expand([], Acc) -> Acc.
+%% Generates a bunch of statistically random bytes using the size as seed.
+gen_determ_rand_bytes(Size) ->
+ gen_determ_rand_bytes(Size, erlang:md5_init(), <<>>).
+gen_determ_rand_bytes(Size, _Context, Acc) when Size =< 0 ->
+ Acc;
+gen_determ_rand_bytes(Size, Context0, Acc) when Size > 0 ->
+ Context = erlang:md5_update(Context0, <<Size/integer>>),
+ Checksum = erlang:md5_final(Context),
+ gen_determ_rand_bytes(Size - 16, Context, <<Acc/binary, Checksum/binary>>).