[PATCH] Modify strnstr.c.

[Sichen Zhao]

---
 newlib/libc/string/strnstr.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/newlib/libc/string/strnstr.c b/newlib/libc/string/strnstr.c
index da5e5bd..7c87bbd 100644
--- a/newlib/libc/string/strnstr.c
+++ b/newlib/libc/string/strnstr.c
@@ -44,22 +44,14 @@ __FBSDID("$FreeBSD: head/lib/libc/string/strnstr.c 251069 2013-05-28 20:57:40Z e
  * first slen characters of s.
  */
 char *
-strnstr(const char *s, const char *find, size_t slen)
+strnstr(const char *haystack, const char *needle, size_t haystack_len)
 {
-	char c, sc;
-	size_t len;
+  size_t needle_len = strnlen(needle, haystack_len);
 
-	if ((c = *find++) != '\0') {
-		len = strlen(find);
-		do {
-			do {
-				if (slen-- < 1 || (sc = *s++) == '\0')
-					return (NULL);
-			} while (sc != c);
-			if (len > slen)
-				return (NULL);
-		} while (strncmp(s, find, len) != 0);
-		s--;
-	}
-	return ((char *)s);
+  if (needle_len < haystack_len || !needle[needle_len]) {
+    char *x = memmem(haystack, haystack_len, needle, needle_len);
+    if (x && !memchr(haystack, 0, x - haystack))
+      return x;
+  }
+  return NULL;
 }
-- 
2.7.4