diff options
Diffstat (limited to 'lib/kernel')
| -rw-r--r-- | lib/kernel/test/Makefile | 4 | ||||
| -rw-r--r-- | lib/kernel/test/kernel_bench.spec | 1 | ||||
| -rw-r--r-- | lib/kernel/test/zlib_SUITE.erl | 351 |
3 files changed, 258 insertions, 98 deletions
diff --git a/lib/kernel/test/Makefile b/lib/kernel/test/Makefile index b9942e899f..efe3a68531 100644 --- a/lib/kernel/test/Makefile +++ b/lib/kernel/test/Makefile @@ -148,8 +148,8 @@ release_tests_spec: make_emakefile $(INSTALL_DIR) "$(RELSYSDIR)" $(INSTALL_DATA) $(ERL_FILES) "$(RELSYSDIR)" $(INSTALL_DATA) $(APP_FILES) "$(RELSYSDIR)" - $(INSTALL_DATA) kernel.spec kernel_smoke.spec $(EMAKEFILE)\ - $(COVERFILE) "$(RELSYSDIR)" + $(INSTALL_DATA) kernel.spec kernel_smoke.spec kernel_bench.spec \ + $(EMAKEFILE) $(COVERFILE) "$(RELSYSDIR)" chmod -R u+w "$(RELSYSDIR)" @tar cf - *_SUITE_data | (cd "$(RELSYSDIR)"; tar xf -) diff --git a/lib/kernel/test/kernel_bench.spec b/lib/kernel/test/kernel_bench.spec new file mode 100644 index 0000000000..8de60dae31 --- /dev/null +++ b/lib/kernel/test/kernel_bench.spec @@ -0,0 +1 @@ +{groups,"../kernel_test",zlib_SUITE,[bench]}. 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>>). |