2010-01-18 15:23:27

by André Goddard Rosa

[permalink] [raw]
Subject: [PATCH] string: simplify stricmp() and strnstr()

Refactor the code and removes an unneeded variable.

It removes 32 bytes on my core2 with gcc 4.4.1:
text data bss dec hex filename
3196 0 0 3196 c7c lib/string-BEFORE.o
3164 0 0 3164 c5c lib/string-AFTER.o

Signed-off-by: André Goddard Rosa <[email protected]>
cc: Li Zefan <[email protected]>
cc: Joe Perches <[email protected]>
cc: Frederic Weisbecker <[email protected]>
cc: Andrew Morton <[email protected]>
---
lib/string.c | 40 ++++++++++++++++++----------------------
1 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/lib/string.c b/lib/string.c
index a1cdcfc..f71bead 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -36,25 +36,21 @@ int strnicmp(const char *s1, const char *s2, size_t len)
/* Yes, Virginia, it had better be unsigned */
unsigned char c1, c2;

- c1 = c2 = 0;
- if (len) {
- do {
- c1 = *s1;
- c2 = *s2;
- s1++;
- s2++;
- if (!c1)
- break;
- if (!c2)
- break;
- if (c1 == c2)
- continue;
- c1 = tolower(c1);
- c2 = tolower(c2);
- if (c1 != c2)
- break;
- } while (--len);
- }
+ if (!len)
+ return 0;
+
+ do {
+ c1 = *s1++;
+ c2 = *s2++;
+ if (!c1 || !c2)
+ break;
+ if (c1 == c2)
+ continue;
+ c1 = tolower(c1);
+ c2 = tolower(c2);
+ if (c1 != c2)
+ break;
+ } while (--len);
return (int)c1 - (int)c2;
}
EXPORT_SYMBOL(strnicmp);
@@ -693,13 +689,13 @@ EXPORT_SYMBOL(strstr);
*/
char *strnstr(const char *s1, const char *s2, size_t len)
{
- size_t l1 = len, l2;
+ size_t l2;

l2 = strlen(s2);
if (!l2)
return (char *)s1;
- while (l1 >= l2) {
- l1--;
+ while (len >= l2) {
+ len--;
if (!memcmp(s1, s2, l2))
return (char *)s1;
s1++;
--
1.6.6.201.g56119