+(defun get-fd-stream-character-sizer (stream)
+ (dolist (entry *external-formats*)
+ (when (member (fd-stream-external-format stream) (first entry))
+ (return-from get-fd-stream-character-sizer (ninth entry)))))
+
+(defun fd-stream-character-size (stream char)
+ (let ((sizer (get-fd-stream-character-sizer stream)))
+ (when sizer (funcall sizer char))))
+
+(defun fd-stream-string-size (stream string)
+ (let ((sizer (get-fd-stream-character-sizer stream)))
+ (when sizer
+ (loop for char across string summing (funcall sizer char)))))
+