anchor.diff:  	      ;; not both suitable for unicode-mode => next char can be encoded smally (1byte).
   	      (encoded-1byte-p state next-code-point)
   	      (find-suitable-static-window next-code-point)
  -	      #+()			; TODO
  -	      (find-suitable-dynamic-window state next-code-point))
  +	      ;; I don't check with FIND-SUITABLE-DYNAMIC-WINDOW,
  +	      ;; because "SQU, <unicode>, SCn" sequence is same length
  +	      ;; with "SCU, <unicode>, UCn" sequence.
  +	      )
   	  ;; quote unicode.
   	  (funcall write-func +SQU+)
   	  (if (> code-point #xFFFF)
  
positive.code: 
  (defun decode-unit (state read-func)
    (prog2 (scsu-trace-output "~&")
        (decode-unit* state read-func)
      (scsu-trace-output "~%")))
  
  (defun decode-to-string (bytes
  
negative.code: 				   (values string dst src state))))
  	      (let ((code-point (decode-unit state #'pick-byte)))
  		(declare (type unicode-code-point code-point))
  		(if (>= code-point char-code-limit) ; For UTF-16 string implementation (i.e. Allegro CL)
  		    (multiple-value-bind (high low)
  			(encode-to-surrogate-pair code-point)
  		      (put-char (code-char high))
  		      (put-char (code-char low)))
  		    (put-char (code-char code-point))))))
        (values string dst-current src-current state))))
  
  (defun decode-unit-from-bytes (bytes &key (start 0) (end (length bytes))
  