%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2000-2012. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
-module(bs_construct_SUITE).
%% Copied from bs_construct_SUITE in the emulator test suite.
%% The following test cases have been omitted since they don't
%% make much sense for the debugger:
%% bs_add
%% kostis
-export([all/0, suite/0,groups/0,init_per_group/2,end_per_group/2,
init_per_testcase/2,end_per_testcase/2,
init_per_suite/1,end_per_suite/1,
test1/1, test2/1, test3/1, test4/1, test5/1, testf/1,
not_used/1, in_guard/1,
mem_leak/1, coerce_to_float/1, bjorn/1,
huge_float_field/1, huge_binary/1, system_limit/1, badarg/1,
copy_writable_binary/1, dynamic/1,
otp_7422/1, zero_width/1]).
-include_lib("test_server/include/test_server.hrl").
suite() -> [{ct_hooks,[ts_install_cth]}].
all() ->
[test1, test2, test3, test4, test5, testf, not_used,
in_guard, mem_leak, coerce_to_float, bjorn,
huge_float_field, huge_binary, system_limit, badarg,
copy_writable_binary, dynamic, otp_7422, zero_width].
groups() ->
[].
init_per_group(_GroupName, Config) ->
Config.
end_per_group(_GroupName, Config) ->
Config.
init_per_testcase(_Case, Config) ->
test_lib:interpret(?MODULE),
Dog = test_server:timetrap(?t:minutes(15)),
[{watchdog,Dog}|Config].
end_per_testcase(_Case, Config) ->
Dog = ?config(watchdog, Config),
?t:timetrap_cancel(Dog),
ok.
init_per_suite(Config) when is_list(Config) ->
?line test_lib:interpret(?MODULE),
?line true = lists:member(?MODULE, int:interpreted()),
Config.
end_per_suite(Config) when is_list(Config) ->
ok.
big(1) ->
57285702734876389752897683.
i(X) -> X.
r(L) ->
lists:reverse(L).
-define(T(B, L), {B, ??B, L}).
-define(N(B), {B, ??B, unknown}).
-define(FAIL(Expr), ?line fail_check(catch Expr, ??Expr, [])).
-define(FAIL_VARS(Expr, Vars), ?line fail_check(catch Expr, ??Expr, Vars)).
l(I_13, I_big1) ->
[
?T(<<-43>>,
[256-43]),
?T(<<56>>,
[56]),
?T(<<1,2>>,
[1, 2]),
?T(<<4:4, 7:4>>,
[4*16+7]),
?T(<<777:16/big>>,
[3, 9]),
?T(<<777:16/little>>,
[9, 3]),
?T(<<0.0:32/float>>,
[0,0,0,0]),
?T(<<0.125:32/float>>,
[62,0,0,0]),
?T(<<0.125:32/little-float>>,
[0,0,0,62]),
?T(<<I_big1:32>>,
[138, 99, 0, 147]),
?T(<<57285702734876389752897684:32>>,
[138, 99, 0, 148]),
?T(<<I_big1:32/little>>,
r([138, 99, 0, 147])),
?T(<<-1:17/unit:8>>,
lists:duplicate(17, 255)),
?T(<<I_13>>,
[13]),
?T(<<4:8/unit:2,5:2/unit:8>>,
[0, 4, 0, 5]),
?T(<<1:1, 0:6, 1:1>>,
[129]),
?T(<<1:1/little, 0:6/little, 1:1/little>>,
[129]),
?T(<<<<1,2>>/binary>>,
[1, 2]),
?T(<<<<1,2>>:1/binary>>,
[1]),
?T(<<4,3,<<1,2>>:1/binary>>,
[4,3,1]),
?T(<<(256*45+47)>>,
[47]),
?T(<<57:0>>,
[]),
?T(<<"apa">>,
"apa"),
?T(<<1:3,"string",9:5>>,
[46,110,142,77,45,204,233]),
?T(<<>>,
[]),
?T(<<37.98:64/native-float>>,
native_3798()),
?T(<<32978297842987249827298387697777669766334937:128/native-integer>>,
native_bignum()),
%% Unit tests.
?T(<<<<5:3>>/bitstring>>, <<5:3>>),
?T(<<42,<<7:4>>/binary-unit:4>>, <<42,7:4>>),
?T(<<<<344:17>>/binary-unit:17>>, <<344:17>>),
?T(<<<<42,3,7656:16>>/binary-unit:16>>, <<42,3,7656:16>>)
].
native_3798() ->
case <<1:16/native>> of
<<0,1>> -> [64,66,253,112,163,215,10,61];
<<1,0>> -> [61,10,215,163,112,253,66,64]
end.
native_bignum() ->
case <<1:16/native>> of
<<0,1>> -> [129,205,18,177,1,213,170,101,39,231,109,128,176,11,73,217];
<<1,0>> -> [217,73,11,176,128,109,231,39,101,170,213,1,177,18,205,129]
end.
evaluate(Str, Vars) ->
{ok,Tokens,_} =
erl_scan:string(Str ++ " . "),
{ok, [Expr]} = erl_parse:parse_exprs(Tokens),
case erl_eval:expr(Expr, Vars) of
{value, Result, _} ->
Result
end.
eval_list([], _Vars) ->
[];
eval_list([{C_bin, Str, Bytes} | Rest], Vars) ->
case catch evaluate(Str, Vars) of
{'EXIT', Error} ->
io:format("Evaluation error: ~p, ~p, ~p~n", [Str, Vars, Error]),
exit(Error);
E_bin ->
[{C_bin, E_bin, Str, Bytes} | eval_list(Rest, Vars)]
end.
one_test({C_bin, E_bin, Str, Bytes}) when is_list(Bytes) ->
io:format(" ~s, ~p~n", [Str, Bytes]),
Bin = list_to_binary(Bytes),
if
C_bin == Bin ->
ok;
true ->
io:format("ERROR: Compiled: ~p. Expected ~p. Got ~p.~n",
[Str, Bytes, binary_to_list(C_bin)]),
test_server:fail(comp)
end,
if
E_bin == Bin ->
ok;
true ->
io:format("ERROR: Interpreted: ~p. Expected ~p. Got ~p.~n",
[Str, Bytes, binary_to_list(E_bin)]),
test_server:fail(comp)
end;
one_test({C_bin, E_bin, Str, Result}) ->
io:format(" ~s ~p~n", [Str, C_bin]),
if
C_bin == E_bin ->
ok;
true ->
Arbitrary = case Result of
unknown ->
size(C_bin);
_ ->
Result
end,
case equal_lists(binary_to_list(C_bin),
binary_to_list(E_bin),
Arbitrary) of
false ->
io:format("ERROR: Compiled not equal to interpreted:"
"~n ~p, ~p.~n",
[binary_to_list(C_bin), binary_to_list(E_bin)]),
test_server:fail(comp);
0 ->
ok;
%% For situations where the final bits may not matter, like
%% for floats:
N when is_integer(N) ->
io:format("Info: compiled and interpreted differ in the"
" last bytes:~n ~p, ~p.~n",
[binary_to_list(C_bin), binary_to_list(E_bin)]),
ok
end
end.
equal_lists([], [], _) ->
0;
equal_lists([], _, _) ->
false;
equal_lists(_, [], _) ->
false;
equal_lists([A|AR], [A|BR], R) ->
equal_lists(AR, BR, R);
equal_lists(A, B, R) ->
if
length(A) /= length(B) ->
false;
length(A) =< R ->
R;
true ->
false
end.
fail_check({'EXIT',{badarg,_}}, Str, Vars) ->
try evaluate(Str, Vars) of
Res ->
io:format("Interpreted result: ~p", [Res]),
?t:fail(did_not_fail_in_intepreted_code)
catch
error:badarg ->
ok
end;
fail_check(Res, _, _) ->
io:format("Compiled result: ~p", [Res]),
?t:fail(did_not_fail_in_compiled_code).
%%% Simple working cases
test1(suite) -> [];
test1(Config) when is_list(Config) ->
?line I_13 = i(13),
?line I_big1 = big(1),
?line Vars = [{'I_13', I_13},
{'I_big1', I_big1}],
?line lists:foreach(fun one_test/1, eval_list(l(I_13, I_big1), Vars)).
%%% Misc
%%% <<A:S, A:(N-S)>>
comp(N, A, S) ->
M1 = (1 bsl S) - 1,
M2 = (1 bsl (N-S)) - 1,
[((A band M1) bsl (N-S)) bor (A band M2)].
gen(N, S, A) ->
[?T(<<A:S, A:(N-S)>>, comp(N, A, S))].
gen_l(N, S, A) ->
[?T(<<A:S/little, A:(N-S)/little>>, comp(N, A, S))].
test2(suite) -> [];
test2(Config) when is_list(Config) ->
?line test2(0, 8, 2#10101010101010101),
?line test2(0, 8, 2#1111111111).
test2(End, End, _) ->
ok;
test2(I, End, A) ->
test2(I, A),
test2(I+1, End, A).
test2(S, A) ->
N = 8,
Vars = [{'A',A}, {'N',N}, {'S',S}],
io:format("Vars: ~p\n", [Vars]),
lists:foreach(fun one_test/1, eval_list(gen(N, S, A), Vars)),
lists:foreach(fun one_test/1, eval_list(gen_l(N, S, A), Vars)).
%%% Tests without facit
t3() ->
[?N(<<4711:13, 9876:13, 3:6>>),
?N(<<4.57:64/float>>),
?N(<<4.57:32/float>>),
?N(<<>>)
].
test3(suite) -> [];
test3(Config) when is_list(Config) ->
?line Vars = [],
?line lists:foreach(fun one_test/1, eval_list(t3(), Vars)).
gen_u(N, S, A) ->
[?N(<<A:S, A:(N-S)>>)].
gen_u_l(N, S, A) ->
[?N(<<A:S/little, A:(N-S)/little>>)].
test4(suite) -> [];
test4(Config) when is_list(Config) ->
?line test4(0, 16, 2#10101010101010101),
?line test4(0, 16, 2#1111111111).
test4(End, End, _) ->
ok;
test4(I, End, A) ->
test4(I, A),
test4(I+1, End, A).
test4(S, A) ->
N = 16,
Vars = [{'A', A}, {'N', 16}, {'S', S}],
lists:foreach(fun one_test/1, eval_list(gen_u(N, S, A), Vars)),
lists:foreach(fun one_test/1, eval_list(gen_u_l(N, S, A), Vars)).
gen_b(N, S, A) ->
[?T(<<A:S/binary-unit:1, A:(N-S)/binary-unit:1>>,
binary_to_list(<<A:S/binary-unit:1, A:(N-S)/binary-unit:1>>))].
test5(suite) -> [];
test5(doc) -> ["OTP-3995"];
test5(Config) when is_list(Config) ->
?line test5(0, 8, <<73>>),
?line test5(0, 8, <<68>>).
test5(End, End, _) ->
ok;
test5(I, End, A) ->
test5(I, A),
test5(I+1, End, A).
test5(S, A) ->
N = 8,
Vars = [{'A', A}, {'N', 8}, {'S', S}],
lists:foreach(fun one_test/1, eval_list(gen_b(N, S, A), Vars)).
%%% Failure cases
testf(suite) -> [];
testf(Config) when is_list(Config) ->
?line ?FAIL(<<3.14>>),
?line ?FAIL(<<<<1,2>>>>),
?line ?FAIL(<<2.71/binary>>),
?line ?FAIL(<<24334/binary>>),
?line ?FAIL(<<24334344294788947129487129487219847/binary>>),
BigInt = id(24334344294788947129487129487219847),
?line ?FAIL_VARS(<<BigInt/binary>>, [{'BigInt',BigInt}]),
?line ?FAIL_VARS(<<42,BigInt/binary>>, [{'BigInt',BigInt}]),
?line ?FAIL_VARS(<<BigInt:2/binary>>, [{'BigInt',BigInt}]),
%% One negative field size, but the sum of field sizes will be 1 byte.
%% Make sure that we reject that properly.
I_minus_777 = id(-777),
I_minus_2047 = id(-2047),
?line ?FAIL_VARS(<<I_minus_777:2048/unit:8,57:I_minus_2047/unit:8>>,
ordsets:from_list([{'I_minus_777',I_minus_777},
{'I_minus_2047',I_minus_2047}])),
?line ?FAIL(<<<<1,2,3>>/float>>),
%% Negative field widths.
?line testf_1(-8, <<1,2,3,4,5>>),
?line ?FAIL(<<0:(-(1 bsl 100))>>),
?line ?FAIL(<<42:(-16)>>),
?line ?FAIL(<<3.14:(-8)/float>>),
?line ?FAIL(<<<<23,56,0,2>>:(-16)/binary>>),
?line ?FAIL(<<<<23,56,0,2>>:(2.5)/binary>>),
?line ?FAIL(<<<<23,56,0,2>>:(anka)>>),
?line ?FAIL(<<<<23,56,0,2>>:(anka)>>),
%% Unit failures.
?line ?FAIL(<<<<1:1>>/binary>>),
Sz = id(1),
?line ?FAIL_VARS(<<<<1:Sz>>/binary>>, [{'Sz',Sz}]),
?line {'EXIT',{badarg,_}} = (catch <<<<1:(id(1))>>/binary>>),
?line ?FAIL(<<<<7,8,9>>/binary-unit:16>>),
?line ?FAIL(<<<<7,8,9,3:7>>/binary-unit:16>>),
?line ?FAIL(<<<<7,8,9,3:7>>/binary-unit:17>>),
ok.
testf_1(W, B) ->
Vars = [{'W',W}],
?FAIL_VARS(<<42:W>>, Vars),
?FAIL_VARS(<<3.14:W/float>>, Vars),
?FAIL_VARS(<<B:W/binary>>, [{'B',B}|Vars]).
not_used(doc) ->
"Test that constructed binaries that are not used will still give an exception.";
not_used(Config) when is_list(Config) ->
?line ok = not_used1(3, <<"dum">>),
?line {'EXIT',{badarg,_}} = (catch not_used1(3, "dum")),
?line {'EXIT',{badarg,_}} = (catch not_used2(444, -2)),
?line {'EXIT',{badarg,_}} = (catch not_used2(444, anka)),
?line {'EXIT',{badarg,_}} = (catch not_used3(444)),
ok.
not_used1(I, BinString) ->
<<I:32,BinString/binary>>,
ok.
not_used2(I, Sz) ->
<<I:Sz>>,
ok.
not_used3(I) ->
<<I:(-8)>>,
ok.
in_guard(Config) when is_list(Config) ->
?line 1 = in_guard(<<16#74ad:16>>, 16#e95, 5),
?line 2 = in_guard(<<16#3A,16#F7,"hello">>, 16#3AF7, <<"hello">>),
?line 3 = in_guard(<<16#FBCD:14,3.1415/float,3:2>>, 16#FBCD, 3.1415),
nope = in_guard(<<1>>, 42, b),
nope = in_guard(<<1>>, a, b),
nope = in_guard(<<1,2>>, 1, 1),
nope = in_guard(<<4,5>>, 1, 2.71),
nope = in_guard(<<4,5>>, 1, <<12,13>>),
ok.
in_guard(Bin, A, B) when <<A:13,B:3>> == Bin -> 1;
in_guard(Bin, A, B) when <<A:16,B/binary>> == Bin -> 2;
in_guard(Bin, A, B) when <<A:14,B/float,3:2>> == Bin -> 3;
in_guard(Bin, A, B) when {a,b,<<A:14,B/float,3:2>>} == Bin -> cant_happen;
in_guard(_, _, _) -> nope.
mem_leak(doc) -> "Make sure that construction has no memory leak";
mem_leak(Config) when is_list(Config) ->
?line B = make_bin(16, <<0>>),
?line mem_leak(1024, B),
ok.
mem_leak(0, _) -> ok;
mem_leak(N, B) ->
?line big_bin(B, <<23>>),
?line {'EXIT',{badarg,_}} = (catch big_bin(B, bad)),
maybe_gc(),
mem_leak(N-1, B).
big_bin(B1, B2) ->
<<B1/binary,B1/binary,B1/binary,B1/binary,
B1/binary,B1/binary,B1/binary,B1/binary,
B1/binary,B1/binary,B1/binary,B1/binary,
B1/binary,B1/binary,B1/binary,B1/binary,
B2/binary>>.
make_bin(0, Acc) -> Acc;
make_bin(N, Acc) -> make_bin(N-1, <<Acc/binary,Acc/binary>>).
maybe_gc() ->
case erlang:system_info(heap_type) of
shared -> erlang:garbage_collect();
hybrid -> erlang:garbage_collect();
private -> ok
end.
-define(COF(Int0),
?line (fun(Int) ->
true = <<Int:32/float>> =:= <<(float(Int)):32/float>>,
true = <<Int:64/float>> =:= <<(float(Int)):64/float>>
end)(nonliteral(Int0)),
?line true = <<Int0:32/float>> =:= <<(float(Int0)):32/float>>,
?line true = <<Int0:64/float>> =:= <<(float(Int0)):64/float>>).
-define(COF64(Int0),
?line (fun(Int) ->
true = <<Int:64/float>> =:= <<(float(Int)):64/float>>
end)(nonliteral(Int0)),
?line true = <<Int0:64/float>> =:= <<(float(Int0)):64/float>>).
nonliteral(X) -> X.
coerce_to_float(Config) when is_list(Config) ->
?COF(0),
?COF(-1),
?COF(1),
?COF(42),
?COF(255),
?COF(-255),
?COF(38474),
?COF(387498738948729893849444444443),
?COF(-37489378937773899999999999999993),
?COF64(298748888888888888888888888883478264866528467367364766666666666666663),
?COF64(-367546729879999999999947826486652846736736476555566666663),
ok.
bjorn(Config) when is_list(Config) ->
?line error = bjorn_1(),
ok.
bjorn_1() ->
Bitstr = <<7:13>>,
try
do_something()
catch
throw:blurf ->
ignore
end,
do_more(Bitstr, 13).
do_more(Bin, Sz) ->
%% Previous bug in the bs_bits_to_bytes instruction: The exeption code
%% was not set - the previous exception (throw:blurf) would be used,
%% causing the catch to slip.
try <<Bin:Sz/binary>> of
_V -> ok
catch
error:_ ->
error
end.
do_something() ->
throw(blurf).
huge_float_field(Config) when is_list(Config) ->
?line {'EXIT',{badarg,_}} = (catch <<0.0:9/float-unit:8>>),
?line huge_float_check(catch <<0.0:67108865/float-unit:64>>),
?line huge_float_check(catch <<0.0:((1 bsl 26)+1)/float-unit:64>>),
?line huge_float_check(catch <<0.0:(id(67108865))/float-unit:64>>),
%% ?line huge_float_check(catch <<0.0:((1 bsl 60)+1)/float-unit:64>>),
?line huge_float_check(catch <<3839739387439387383739387987347983:((1 bsl 26)+1)/float-unit:64>>),
%% ?line huge_float_check(catch <<3839739387439387383739387987347983:((1 bsl 60)+1)/float-unit:64>>),
ok.
huge_float_check({'EXIT',{system_limit,_}}) -> ok;
huge_float_check({'EXIT',{badarg,_}}) -> ok.
huge_binary(Config) when is_list(Config) ->
?line 16777216 = size(<<0:(id(1 bsl 26)),(-1):(id(1 bsl 26))>>),
ok.
system_limit(Config) when is_list(Config) ->
WordSize = erlang:system_info(wordsize),
BitsPerWord = WordSize * 8,
?line {'EXIT',{system_limit,_}} =
(catch <<0:(id(0)),42:(id(1 bsl BitsPerWord))>>),
?line {'EXIT',{system_limit,_}} =
(catch <<42:(id(1 bsl BitsPerWord)),0:(id(0))>>),
?line {'EXIT',{system_limit,_}} =
(catch <<(id(<<>>))/binary,0:(id(1 bsl 100))>>),
case WordSize of
4 ->
system_limit_32();
8 ->
ok
end.
system_limit_32() ->
?line {'EXIT',{badarg,_}} = (catch <<42:(-1)>>),
?line {'EXIT',{badarg,_}} = (catch <<42:(id(-1))>>),
?line {'EXIT',{badarg,_}} = (catch <<42:(id(-389739873536870912))/unit:8>>),
?line {'EXIT',{system_limit,_}} = (catch <<42:536870912/unit:8>>),
?line {'EXIT',{system_limit,_}} = (catch <<42:(id(536870912))/unit:8>>),
?line {'EXIT',{system_limit,_}} = (catch <<0:(id(8)),42:536870912/unit:8>>),
?line {'EXIT',{system_limit,_}} =
(catch <<0:(id(8)),42:(id(536870912))/unit:8>>),
ok.
badarg(Config) when is_list(Config) ->
%% BEAM will generate a badarg exception for:
%% <<0:(id(1 bsl 100)),0:(id(-1))>>
%% but the debugger will generate a system_limit exception.
%% It does not seems worthwhile to fix the debugger.
?line {'EXIT',{badarg,_}} =
(catch <<(id(<<>>))/binary,0:(id(-(1 bsl 100)))>>),
ok.
copy_writable_binary(Config) when is_list(Config) ->
?line [copy_writable_binary_1(I) || I <- lists:seq(0, 256)],
ok.
copy_writable_binary_1(_) ->
?line Bin0 = <<(id(<<>>))/binary,0,1,2,3,4,5,6,7>>,
?line SubBin = make_sub_bin(Bin0),
?line id(<<42,34,55,Bin0/binary>>), %Make reallocation likelier.
?line Pid = spawn(fun() ->
copy_writable_binary_holder(Bin0, SubBin)
end),
?line Tab = ets:new(holder, []),
?line ets:insert(Tab, {17,Bin0}),
?line ets:insert(Tab, {42,SubBin}),
?line id(<<Bin0/binary,0:(64*1024*8)>>),
?line Pid ! self(),
?line [{17,Bin0}] = ets:lookup(Tab, 17),
?line [{42,Bin0}] = ets:lookup(Tab, 42),
receive
{Pid,Bin0,Bin0} -> ok;
Other ->
io:format("Unexpected message: ~p", [Other]),
?line ?t:fail()
end,
ok.
copy_writable_binary_holder(Bin, SubBin) ->
receive
Pid ->
Pid ! {self(),Bin,SubBin}
end.
make_sub_bin(Bin0) ->
N = bit_size(Bin0),
<<_:17,Bin:N/bitstring,_:5>> = <<(-1):17,Bin0/bitstring,(-1):5>>,
Bin = Bin0, %Assertion.
Bin.
%% Test that different ways of using bit syntax instructions
%% give the same result.
dynamic(Config) when is_list(Config) ->
?line dynamic_1(fun dynamic_big/5),
?line dynamic_1(fun dynamic_little/5),
ok.
dynamic_1(Dynamic) ->
<<Lpad:128>> = erlang:md5([0]),
<<Rpad:128>> = erlang:md5([1]),
<<Int:128>> = erlang:md5([2]),
8385 = dynamic_2(0, {Int,Lpad,Rpad,Dynamic}, 0).
dynamic_2(129, _, Count) -> Count;
dynamic_2(Bef, Data, Count0) ->
Count = dynamic_3(Bef, 128-Bef, Data, Count0),
dynamic_2(Bef+1, Data, Count).
dynamic_3(_, -1, _, Count) -> Count;
dynamic_3(Bef, N, {Int0,Lpad,Rpad,Dynamic}=Data, Count) ->
Int1 = Int0 band ((1 bsl (N+3))-1),
Dynamic(Bef, N, Int1, Lpad, Rpad),
Dynamic(Bef, N, -Int1, Lpad, Rpad),
%% OTP-7085: Test a small number in a wide field.
Int2 = Int0 band 16#FFFFFF,
Dynamic(Bef, N, Int2, Lpad, Rpad),
Dynamic(Bef, N, -Int2, Lpad, Rpad),
dynamic_3(Bef, N-1, Data, Count+1).
dynamic_big(Bef, N, Int, Lpad, Rpad) ->
NumBin = id(<<Int:N>>),
MaskedInt = Int band ((1 bsl N) - 1),
<<MaskedInt:N>> = NumBin,
%% Construct the binary in two different ways.
Bin = id(<<Lpad:Bef,NumBin/bitstring,Rpad:(128-Bef-N)>>),
Bin = <<Lpad:Bef,Int:N,Rpad:(128-Bef-N)>>,
%% Further verify the result by matching.
LpadMasked = Lpad band ((1 bsl Bef) - 1),
RpadMasked = Rpad band ((1 bsl (128-Bef-N)) - 1),
Rbits = (128-Bef-N),
<<LpadMasked:Bef,MaskedInt:N,RpadMasked:Rbits>> = id(Bin),
ok.
dynamic_little(Bef, N, Int, Lpad, Rpad) ->
NumBin = id(<<Int:N/little>>),
MaskedInt = Int band ((1 bsl N) - 1),
<<MaskedInt:N/little>> = NumBin,
%% Construct the binary in two different ways.
Bin = id(<<Lpad:Bef/little,NumBin/bitstring,Rpad:(128-Bef-N)/little>>),
Bin = <<Lpad:Bef/little,Int:N/little,Rpad:(128-Bef-N)/little>>,
%% Further verify the result by matching.
LpadMasked = Lpad band ((1 bsl Bef) - 1),
RpadMasked = Rpad band ((1 bsl (128-Bef-N)) - 1),
Rbits = (128-Bef-N),
<<LpadMasked:Bef/little,MaskedInt:N/little,RpadMasked:Rbits/little>> = id(Bin),
ok.
otp_7422(Config) when is_list(Config) ->
otp_7422_int(0),
otp_7422_bin(0).
otp_7422_int(N) when N < 512 ->
T = erlang:make_tuple(N, []),
spawn_link(fun() ->
id(T),
%% A size of field 0 would write one byte beyond
%% the current position in the binary. It could
%% overwrite the continuation pointer stored on
%% the stack if HTOP was equal to E (the stack pointer).
id(<<0:(id(0))>>)
end),
otp_7422_int(N+1);
otp_7422_int(_) -> ok.
otp_7422_bin(N) when N < 512 ->
T = erlang:make_tuple(N, []),
Z = id(<<>>),
spawn_link(fun() ->
id(T),
id(<<Z:(id(0))/bits>>)
end),
otp_7422_bin(N+1);
otp_7422_bin(_) -> ok.
zero_width(Config) when is_list(Config) ->
?line Z = id(0),
Small = id(42),
Big = id(1 bsl 128),
?line <<>> = <<Small:Z>>,
?line <<>> = <<Small:0>>,
?line <<>> = <<Big:Z>>,
?line <<>> = <<Big:0>>,
?line {'EXIT',{badarg,_}} = (catch <<not_a_number:0>>),
?line {'EXIT',{badarg,_}} = (catch <<(id(not_a_number)):Z>>),
?line {'EXIT',{badarg,_}} = (catch <<(id(not_a_number)):0>>),
ok.
id(I) -> I.
