-	    return s;
-	} while (--n4 > 0);
-      n &= 3;
-    }
+  size_t ss = __strnlen (s2, n);
 
-  while (n > 0)
-    {
-      c = *s2++;
-      *++s1 = c;
-      if (c == '\0')
-	return s;
-      n--;
-    }
-
-  if (c != '\0')
-    *++s1 = '\0';
+  s1[ss] = '\0';
+  memcpy (s1, s2, ss);
 
   return s;
 }
+