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[PATCH] More effective generic strrchr.
- From: OndÅej BÃlka <neleai at seznam dot cz>
- To: libc-alpha at sourceware dot org
- Date: Sat, 5 Oct 2013 09:15:42 +0200
- Subject: [PATCH] More effective generic strrchr.
- Authentication-results: sourceware.org; auth=none
A generic implementation of strrchr could be improved by following
patch. As it is likely that last occurrence of c will be near we
could quickly find it. This is also much faster for degenerate inputs
where a loop slows us down.
* string/strrchr.c: Improve implementation.
string/strrchr.c | 19 ++-----------------
1 file changed, 2 insertions(+), 17 deletions(-)
diff --git a/string/strrchr.c b/string/strrchr.c
index bdec841..ad242b6 100644
@@ -23,23 +23,8 @@
strrchr (const char *s, int c)
- const char *found, *p;
- c = (unsigned char) c;
- /* Since strchr is fast, we use it rather than the obvious loop. */
- if (c == '\0')
- return strchr (s, '\0');
- found = NULL;
- while ((p = strchr (s, c)) != NULL)
- found = p;
- s = p + 1;
- return (char *) found;
+ /* We need to include terminating zero for case c == 0. */
+ return __memrchr (s, c, strlen (s) + 1);