linux-kernel - [PATCH] lib/string.c: Improve strrchr

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Date:	Wed, 14 Jan 2015 22:01:51 +0100
From:	Rasmus Villemoes <linux@...musvillemoes.dk>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Rasmus Villemoes <linux@...musvillemoes.dk>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] lib/string.c: Improve strrchr

Instead of potentially passing over the string twice in case c is not
found, just keep track of the last occurrence. According to
bloat-o-meter, this also cuts the generated code by a third (54 vs 36
bytes). Oh, and we get rid of those 7-space indented lines.

Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
---
 lib/string.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/string.c b/lib/string.c
index 10063300b830..f112a7fd1893 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -321,12 +321,12 @@ EXPORT_SYMBOL(strchrnul);
  */
 char *strrchr(const char *s, int c)
 {
-       const char *p = s + strlen(s);
-       do {
-           if (*p == (char)c)
-               return (char *)p;
-       } while (--p >= s);
-       return NULL;
+	const char *last = NULL;
+	do {
+		if (*s == (char)c)
+			last = s;
+	} while (*s++);
+	return (char *)last;
 }
 EXPORT_SYMBOL(strrchr);
 #endif
-- 
2.1.3

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