Cast lexer bytes to unsigned char before ctype - #144
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C99 7.4 requires ctype arguments to be EOF or representable as unsigned char. Plain char may be signed; high-bit bytes then become negative ints. Addresses issue codeplea#105.
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Pull request overview
This PR fixes undefined behavior in the lexer by ensuring bytes passed to <ctype.h> classification functions are cast to unsigned char, avoiding negative char values on signed-char platforms.
Changes:
- Cast
s->next[0]to(unsigned char)before callingisalpha. - Cast
s->next[0]to(unsigned char)before callingisdigitin the identifier scan loop.
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Summary
Casts
s->next[0]tounsigned charbeforeisalpha/isdigitinnext_token.Why
#105 (OPEN). On signed-
charplatforms, input byte0x80reachesisalpha(-128), which is undefined under C99 7.4p1. Stock glibc/Darwin often mask it; a trapping ctype aborts.Test plan
make smoke/make smoke_prchartarget,te_interpof a single0x80byte should still reject without UBSan/trap from ctype