*
* This returns a pointer to a struct delta_index that should be passed to
* subsequent create_delta() calls, or to free_delta_index(). A NULL pointer
- * is returned on failure. The given buffer must not be freed nor altered
+ * is returned on failure. The given buffer must not be freed or altered
* before free_delta_index() is called. The returned pointer must be freed
* using free_delta_index().
*/