On Wed, 2016-06-29 at 21:52 +0300, Andy Shevchenko wrote:
> On Wed, 2016-06-29 at 20:31 +0200, Michal Nazarewicz wrote:
[]
> > tolower macro maps to __tolower function which calls isupper to
> > to determine if character is an upper case letter before converting
> > it to lower case. This preservers non-letters unchanged which is
> > what you want in usual case.
> >
> > However, hex_to_bin does not care about non-letter characters so
> > such conversion can be performed as long as (i) upper case letters
> > become lower case, (ii) lower case letters are unchanged and (iii)
> > non-letters stay non-letters.
> >
> > This is exactly what _tolower function does and using it makes it
> > possible to avoid _ctype table lookup performed by the isupper
> > table.
> >
> > Furthermore, since _tolower conversion is done unconditionally, this
> > also eliminates a single branch.
> This change I agree with since _tolower() is specific for lib internal
> usage in the kernel.
Perhaps _tolower should be used a bit more in lib
---
lib/string.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/lib/string.c b/lib/string.c
index ed83562..b0e72fd 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -53,8 +53,8 @@ int strncasecmp(const char *s1, const char *s2, size_t len)
break;
if (c1 == c2)
continue;
- c1 = tolower(c1);
- c2 = tolower(c2);
+ c1 = _tolower(c1);
+ c2 = _tolower(c2);
if (c1 != c2)
break;
} while (--len);
@@ -69,8 +69,8 @@ int strcasecmp(const char *s1, const char *s2)
int c1, c2;
do {
- c1 = tolower(*s1++);
- c2 = tolower(*s2++);
+ c1 = _tolower(*s1++);
+ c2 = _tolower(*s2++);
} while (c1 == c2 && c1 != 0);
return c1 - c2;
}
