paw: spkg: Add more string functions

Signed-off-by: Chloe M. <chloe@mensia.org>

paw/spkg/head/string.h

@@ -22,4 +22,35 @@
  */
 LONG RtlMemCmp(const VOID *Buffer1, const VOID *Buffer2, USIZE Length);
 
+/*
+ * Obtain the length in bytes of a '\0' terminated string
+ *
+ * @String: String to obtain length from
+ *
+ * Returns zero on failure
+ */
+USIZE RtlStrLen(const CHAR *String);
+
+/*
+ * Fill n bytes of a buffer with a value
+ *
+ * @Buffer:     Pointer to buffer to fill
+ * @SetValue:   Value to fill with
+ * @Length:     Number of bytes to fill
+ *
+ * Returns @Buffer on success, otherwise NULL on failure
+ */
+VOID *RtlMemSet(VOID *Buffer, LONG SetValue, USIZE Length);
+
+/*
+ * Copy n bytes of one buffer to another
+ *
+ * @Dest: Destination buffer
+ * @Soruce: Source buffer
+ * @Length: Length of buffers
+ *
+ * Returns @Dest on suucess, otherwise NULL on failure
+ */
+VOID *RtlMemCpy(VOID *Dest, const VOID *Source, USIZE Length);
+
 #endif  /* !_SPKG_STRING_H_ */