anchor.diff:  
   If FINISHP is true, then in addition to any encoding of OCTETS, also output
   any necessary padding required by FORMAT."
  -  (let ((format-state (find-format format)))
  +  (let ((state (find-encoder format))
  +        (fd (state-descriptor state)))
  +    (declare (type encode-state state))
  +    (declare (type format-descriptor fd))
       (flet ((frob (encode-fun)
                (multiple-value-bind (input input-start input-end)
                    (array-data-and-offsets octets start end)
  
positive.code:         (null
           (decode-to-fresh-vector string format-start start end))
          (string
           (frob (decode-state-string->octets format-state)))
          ((array (unsigned-byte 8) (*))
           (frob (decode-state-octets->octets format-state)))))))
  ||#
  
  (defun decode-octets (destination string format
  
negative.code:         (declare (inline frob))
          (ecase (canonical-element-type element-type)
            (character
             (frob 'character (fd-octets->string fd)))
            (base-char
             (frob 'base-char (fd-octets->string fd)))
            (ub8
             (frob '(unsigned-byte 8) (fd-octets->octets/encode fd))))))))
  
  (defun encode (octets format &key (start 0) end (element-type 'base-char))
    (encode-to-fresh-vector octets format start end element-type))
  