Very small update to strlen and strnlen that now use less cpu
instructions by using a counter to avoid the memory addresses
substraction to find the length of the string.
Signed-off-by: Orestes Leal Rodriguez <lukes...@gmail.com>
---
diff --git a/lib/string.c" "b/lib/string.c
index 992bf30..c873436 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -17,6 +17,10 @@
* * Sat Feb 09 2002, Jason Thomas <ja...@topic.com.au>,
* Matthew Hawkins <m...@mh.dropbear.id.au>
* - Kissed strtok() goodbye
+ *
+ * * Tuesday June 16 2015, Orestes Leal Rodriguez <lukes...@gmail.com>
+ * - strlen, strnlen: by using a single counter we use less cpu
instructions
+ * by avoiding substracting the memory addresses before return
*/
#include <linux/types.h>
@@ -401,11 +405,11 @@ EXPORT_SYMBOL(strim);
*/
size_t strlen(const char *s)
{
- const char *sc;
+ size_t sz = 0;
- for (sc = s; *sc != '\0'; ++sc)
- /* nothing */;
- return sc - s;
+ for (; *s++ != '\0'; sz++)
+ /* empty */;
+ return sz;
}
EXPORT_SYMBOL(strlen);
#endif
@@ -418,12 +422,13 @@ EXPORT_SYMBOL(strlen);
*/
size_t strnlen(const char *s, size_t count)
{
- const char *sc;
+ size_t sz = 0;
- for (sc = s; count-- && *sc != '\0'; ++sc)
- /* nothing */;
- return sc - s;
+ for (; count-- && *s++ != '\0'; sz++)
+ /* empty */;
+ return sz;
}
+
EXPORT_SYMBOL(strnlen);
#endif
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