lib: Introduce strnstr()

[safe/jmp/linux-2.6] / lib / string.c

diff --git a/lib/string.c b/lib/string.c
index afce96a..a1cdcfc 100644 (file)
--- a/lib/string.c
+++ b/lib/string.c
@@ -338,10 +338,10 @@ EXPORT_SYMBOL(strnchr);
 #endif
 
 /**
- * skip_spaces - Removes leading whitespace from @s.
- * @s: The string to be stripped.
+ * skip_spaces - Removes leading whitespace from @str.
+ * @str: The string to be stripped.
  *
- * Returns a pointer to the first non-whitespace character in @s.
+ * Returns a pointer to the first non-whitespace character in @str.
  */
 char *skip_spaces(const char *str)
 {
@@ -667,7 +667,7 @@ EXPORT_SYMBOL(memscan);
  */
 char *strstr(const char *s1, const char *s2)
 {
-       int l1, l2;
+       size_t l1, l2;
 
        l2 = strlen(s2);
        if (!l2)
@@ -684,6 +684,31 @@ char *strstr(const char *s1, const char *s2)
 EXPORT_SYMBOL(strstr);
 #endif
 
+#ifndef __HAVE_ARCH_STRNSTR
+/**
+ * strnstr - Find the first substring in a length-limited string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ * @len: the maximum number of characters to search
+ */
+char *strnstr(const char *s1, const char *s2, size_t len)
+{
+       size_t l1 = len, l2;
+
+       l2 = strlen(s2);
+       if (!l2)
+               return (char *)s1;
+       while (l1 >= l2) {
+               l1--;
+               if (!memcmp(s1, s2, l2))
+                       return (char *)s1;
+               s1++;
+       }
+       return NULL;
+}
+EXPORT_SYMBOL(strnstr);
+#endif
+
 #ifndef __HAVE_ARCH_MEMCHR
 /**
  * memchr - Find a character in an area of memory.