umgeher/jsx
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check for incomplete valid input before checking for malformed utf8

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This commit is contained in:
alisdair sullivan 2013-08-27 05:02:37 +00:00
parent af11b97879
commit 0bbe56c700
1 changed files with 14 additions and 18 deletions
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32
src/jsx_decoder.erl
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@ -531,6 +531,19 @@ string(<<X/utf8, Rest/binary>>, Handler, Acc, Stack, Config) when X >= 16#f0000,
string(Rest, Handler, acc_seq(Acc, X), Stack, Config);
string(<<X/utf8, Rest/binary>>, Handler, Acc, Stack, Config) when X >= 16#100000, X < 16#10fffe ->
string(Rest, Handler, acc_seq(Acc, X), Stack, Config);
%% partial utf8 codepoints. check that input could possibly be valid before attempting
%% to correct
string(<<>>, Handler, Acc, Stack, Config) ->
incomplete(string, <<>>, Handler, Acc, Stack, Config);
string(<<X>>, Handler, Acc, Stack, Config) when X >= 16#c2, X =< 16#f4 ->
incomplete(string, <<X>>, Handler, Acc, Stack, Config);
string(<<X, Y>>, Handler, Acc, Stack, Config) when X >= 16#e0, X =< 16#f4, Y >= 16#80, Y =< 16#bf ->
incomplete(string, <<X, Y>>, Handler, Acc, Stack, Config);
string(<<X, Y, Z>>, Handler, Acc, Stack, Config)
when X >= 16#f0, X =< 16#f4,
Y >= 16#80, Y =< 16#bf,
Z >= 16#80, Z =< 16#bf ->
incomplete(string, <<X, Y, Z>>, Handler, Acc, Stack, Config);
%% surrogates
string(<<237, X, _, Rest/binary>>, Handler, Acc, Stack, Config=#config{replaced_bad_utf8=true})
when X >= 160 ->
@ -559,10 +572,7 @@ string(<<X, Rest/binary>>, Handler, Acc, Stack, Config=#config{replaced_bad_utf8
string(<<_, Rest/binary>>, Handler, Acc, Stack, Config=#config{replaced_bad_utf8=true}) ->
string(Rest, Handler, acc_seq(Acc, 16#fffd), Stack, Config);
string(Bin, Handler, Acc, Stack, Config) ->
case is_partial_utf(Bin) of
true -> incomplete(string, Bin, Handler, Acc, Stack, Config);
false -> ?error(string, Bin, Handler, Acc, Stack, Config)
end.
?error(string, Bin, Handler, Acc, Stack, Config).
doublequote(<<Rest/binary>>, Handler, Acc, [key|_] = Stack, Config) ->
@ -583,20 +593,6 @@ singlequote(<<Rest/binary>>, Handler, Acc, Stack, Config) ->
string(Rest, Handler, acc_seq(Acc, ?singlequote), Stack, Config).
%% when parsing strings, the naive detection of partial codepoints is
%% insufficient. this incredibly anal function should detect all badly formed
%% utf sequences
is_partial_utf(<<>>) -> true;
is_partial_utf(<<X>>) when X >= 16#c2, X =< 16#f4 -> true;
is_partial_utf(<<X, Y>>) when X >= 16#e0, X =< 16#f4, Y >= 16#80, Y =< 16#bf -> true;
is_partial_utf(<<X, Y, Z>>)
when X >= 16#f0, X =< 16#f4,
Y >= 16#80, Y =< 16#bf,
Z >= 16#80, Z =< 16#bf ->
true;
is_partial_utf(_) -> false.
%% strips continuation bytes after bad utf bytes, guards against both too short
%% and overlong sequences. N is the maximum number of bytes to strip
strip_continuations(<<Rest/binary>>, Handler, Acc, Stack, Config, 0) ->