anchor.diff:      (loop FOR (file) IN files
         DO (with-open-file (in file :element-type 'uint1)
              (write-byte (byte-reverse (file-length in) 4) out))))
  -  
  +
     ;; write each file content
     (loop FOR (file type) IN files
           FOR byte-size = (ecase type (uint4 4) (uint8 8))
  
positive.code:           (setf (ldb (byte  8 40) n) (or (first children) 0)
                  (ldb (byte  8 48) n) (or (second children) 0)
                  (ldb (byte  8 56) n) sibling-total))
           (1 
            (setf (ldb (byte  8 40) n) (or (first children) 0)
                  (ldb (byte 16 48) n) sibling-total))
           (2 
            (setf (ldb (byte 24 40) n) sibling-total))
           (3 
            (setf (ldb (byte 24 40) n) (file-position (da-exts da)))
            (write-byte sibling-total (da-exts da))))
  
  
negative.code:     (loop FOR (file) IN files
            DO (with-open-file (in file :element-type 'uint1)
                 (write-byte (file-length in) out))))
  
    ;; write each file content
    (with-open-output-file (out destination 'uint1 :if-exists :append)
      (loop FOR (file) IN files
  