[PATCH] add strcspn() library function

This patch implements a generic strcspn.

include/linux/string.h

@@ -15,7 +15,7 @@ extern "C" {
 extern char * strpbrk(const char *,const char *);
 extern char * strsep(char **,const char *);
 extern __kernel_size_t strspn(const char *,const char *);
-
+extern __kernel_size_t strcspn(const char *,const char *);
 
 /*
  * Include machine specific inline routines

lib/string.c

@@ -272,6 +272,29 @@ size_t strspn(const char *s, const char *accept)
 }
 #endif
 
+/**
+ * strcspn - Calculate the length of the initial substring of @s which does
+ * 	not contain letters in @reject
+ * @s: The string to be searched
+ * @reject: The string to avoid
+ */
+size_t strcspn(const char *s, const char *reject)
+{
+	const char *p;
+	const char *r;
+	size_t count = 0;
+
+	for (p = s; *p != '\0'; ++p) {
+		for (r = reject; *r != '\0'; ++r) {
+			if (*p == *r)
+				return count;
+		}
+		++count;
+	}
+
+	return count;
+}	
+
 #ifndef __HAVE_ARCH_STRPBRK
 /**
  * strpbrk - Find the first occurrence of a set of characters