anchor.diff:            (#xE0 (when (< c #xA0) (return* nil)))
             (#xED (when (> c #x9F) (return* nil)))
             (#xF0 (when (< c #x90) (return* nil)))
  +          #-16bit-chars
             (#xF4 (when (> c #x8F) (return* nil)))
             (t    (when (< c #x80) (return* nil)))))
         (when (>= len 1) (when (<= #x80 srchr #xC1) (return* nil)))
  
positive.code:                ((<  code #x80)     1)
                 ((<  code #x800)    2)
                 ((<  code #x10000)  3)
                 ((<  code #x110000) 4))))
  
  (defun cstring-alloc (sstring)
  
negative.code:                (output-octet (logior #xE0 (ldb (byte 4 12) code)))
                 (output-octet (logior #x80 (ldb (byte 6 6) code)))
                 (output-octet (logior #x80 (ldb (byte 6 0) code))))
                #+21bit-chars
                ((< code #x110000)
                 (output-octet (logior #xF0 (ldb (byte 3 18) code)))
                 (output-octet (logior #x80 (ldb (byte 6 12) code)))
  