Function: SERIALIZE-PREVIOUS-VERSION-POINTER

Source

(defun serialize-previous-version-pointer (previous-pointer stream)
  ;; The previous version pointer is a fixed-width field, so we
  ;; serialize it 'by hand'.
  (if previous-pointer
      (progn
        ;; 1 marker octet plus 6 octets for the 'pointer'.
        (serialize-marker +positive-byte-48+ stream)
        (serialize-byte-48 previous-pointer stream))
    (progn 
      (serialize-marker +nil+ stream)
      ;; Fill up with dummy octets to ensure fixed width.
      (loop repeat 6
            do (serialize-marker +ignore+ stream)))))