Method: (ALLOCATE-BLOCK APPENDING-HEAP)

Source

(defmethod allocate-block ((heap appending-heap) &key size &allow-other-keys)
  (let ((block (heap-end heap)))
    ;; Put block size (including the size of header) into header.
    (setf (block-size block heap) size)
    ;;
    (incf (heap-end heap) size)
    (values block size)))