[PATCH 2/2] lib/string.c: simplify str[c]spn
From: Rasmus Villemoes
Date: Mon Mar 28 2022 - 18:41:43 EST
Use strchr(), which makes them a lot shorter, and more obviously
symmetric in their treatment of accept/reject. It also saves a little
bit of .text; bloat-o-meter for an arm build says
Function old new delta
strcspn 92 76 -16
strspn 108 76 -32
While here, also remove a stray empty line before EXPORT_SYMBOL().
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
lib/string.c | 25 ++++++-------------------
1 file changed, 6 insertions(+), 19 deletions(-)
diff --git a/lib/string.c b/lib/string.c
index 485777c9da83..6f334420f687 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -517,21 +517,13 @@ EXPORT_SYMBOL(strnlen);
size_t strspn(const char *s, const char *accept)
{
const char *p;
- const char *a;
- size_t count = 0;
for (p = s; *p != '\0'; ++p) {
- for (a = accept; *a != '\0'; ++a) {
- if (*p == *a)
- break;
- }
- if (*a == '\0')
- return count;
- ++count;
+ if (!strchr(accept, *p))
+ break;
}
- return count;
+ return p - s;
}
-
EXPORT_SYMBOL(strspn);
#endif
@@ -544,17 +536,12 @@ EXPORT_SYMBOL(strspn);
size_t strcspn(const char *s, const char *reject)
{
const char *p;
- const char *r;
- size_t count = 0;
for (p = s; *p != '\0'; ++p) {
- for (r = reject; *r != '\0'; ++r) {
- if (*p == *r)
- return count;
- }
- ++count;
+ if (strchr(reject, *p))
+ break;
}
- return count;
+ return p - s;
}
EXPORT_SYMBOL(strcspn);
#endif
--
2.31.1