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SubjectRe: 2.6.19: slight performance optimization for lib/string.c's strstrip()
> Suggested replacement:
>
> char *strstrip(char *s)
> {
> size_t size;
> char *end;
>
> while (*s && isspace(*s))
> s++;
> if (!*s)
> return s;
> size = strlen(s);
>
> end = s + size - 1;
> while (end > s && isspace(*end))
> end--;
> *(end + 1) = '\0';
>
> return s;
> }
> EXPORT_SYMBOL(strstrip);

How about this:

char *strstrip(char *s)
{
size_t less = 0;
char c = 0;
char *e = NULL;

while ((c=*s) && isspace(c))
s++;
if (!c)
return s;

e = s;

while (c=*e) {
less = isspace(c) ? (less + 1) : 0;
e++;
}

*(e-less) = 0;

return s;
}

1. no need to scan trailing spaces twice (once in strlen and then again).
2. pointer dereference only once per loop rather than multiple times.

Regards,
Amit

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