anchor.diff:  						:element-type '(unsigned-byte 8)))
   			     (start2 0) (end2 (length bytes))
   			     (initial-priority :lookahead)
  -			     (state (make-instance 'scsu-state)))
  +			     (state (make-instance 'scsu-state))
  +			   &aux (bytes-fill-pointer-at-first (fill-pointer-if-exists bytes)))
     (declare (type string string)
   	   (type (array (unsigned-byte 8) *) bytes)	   
   	   (type fixnum start1 end1 start2 end2))
  
positive.code: 			      &key (bytes (make-array (* 2 +window-count+) ; SDn * 8
  						      :fill-pointer 0
  						      :element-type '(unsigned-byte 8)))
  				(start 0) (end (length bytes)))
    (declare (type (array (unsigned-byte 8) *) bytes)	   
  	   (type fixnum start end))
    (with-buffer-accessor (:writer put-byte :current dst-current)
  
negative.code: 	 do (with-scsu-error-handling
  		(state :src src-current :dst dst-current
  		       :return (lambda (dst src)
  				 (when string-fill-pointer-at-first
  				   (setf (fill-pointer string) (max dst string-fill-pointer-at-first)))
  				 (return-from decode-to-string
  				   (values string dst src state))))
  	      (let ((code-point (decode-unit state #'pick-byte)))
  