Am 17.06.2010, 15:57 Uhr, schrieb Alon Bar-Lev:
Great.
Few more:
1. To upper:
char *s = p[1];
while ((*s = toupper(*s)) != '\0') s++;
I haven't looked at the patch yet, so my silence about anything else DOES
NOT constitute approval or anything of the remainder of the code.
Picking out a random bit: toupper called on (unqualified) char without
cast is A SECURITY RISK and NON-PORTABLE. It can cause BAD ARRAY SUBSCRIPT
compiler warnings AND CRASHES (depending on if the compiler treats the
char as signed or unsigned, which is implementation-dependent). Many libcs
implement toupper via table lookup similar to:
static inline int isupper(int c) {
return !!(ctypes[c+1] & _CUPPER);
}
EVERYBODY MUST ALWAYS cast toupper/tolower/to...() and is...() arguments
to unsigned char:
char *s = ...
while ((*s = toupper((unsigned char)*s) != '\0') ++s;
Alternatively, declare unsigned char *s = ... - which will however cause
signedness mismatches in assignments and thereabouts unless you cast.
That's because all these ctype.h functions take "int" arguments that can
be EOF (-1) or any value representable as unsigned char. Check IEEE Std
1003.1.
--
Matthias Andree
