anchor.diff:  
   (defun read-field-shorts (stream count)
     (if (<= count 2)
  -      (loop for i below 2
  -         for short = (read-int-16 stream)
  -         when (< i count)
  -         collect short)
  +      (vectorize
  +       (loop for i below 2
  +          for short = (read-int-16 stream)
  +          when (< i count)
  +          collect short))
         (let ((offset (read-int-32 stream))
               (field-pos (file-position stream)))
           (file-position stream offset)
  
positive.code:                   (t (let ((value-offset (read-int-32 stream)))
                         value-offset)))))))
  
  (defun ifd-entry-values (ifd-entry)
    (elt ifd-entry 3))
  
  (defun read-ifd (stream)
  
negative.code:   (dotimes (i (length array))
      (write-int-32 stream (aref array i))))
  
  (defun write-int-32-sequence (stream values)
    (if (atom values)
        (write-int-32 stream values)
        (write-int-32-array stream (vectorize values))))
  
  (defun read-rational (stream)
    (/ (read-int-32 stream) (read-int-32 stream)))
  
  