+(defun ez-get-obj-addr (obj)
+ (+ ez-objtab-addr (* 2 31) (* 9 (- obj 1))))
+
+(defun ez-get-obj-parent (obj)
+ (let ((addr (ez-get-obj-addr obj)))
+ (ez-mem-ref-byte (+ addr 4))))
+
+(defun ez-set-obj-parent (obj new-parent)
+ (let ((addr (ez-get-obj-addr obj)))
+ (ez-mem-set-byte (+ addr 4) new-parent)))
+
+(defun ez-get-obj-sibling (obj)
+ (let ((addr (ez-get-obj-addr obj)))
+ (ez-mem-ref-byte (+ addr 5))))
+
+(defun ez-set-obj-sibling (obj new-sibling)
+ (let ((addr (ez-get-obj-addr obj)))
+ (ez-mem-set-byte (+ addr 5) new-sibling)))
+
+(defun ez-get-obj-child (obj)
+ (let ((addr (ez-get-obj-addr obj)))
+ (ez-mem-ref-byte (+ addr 6))))
+
+(defun ez-set-obj-child (obj new-child)
+ (let ((addr (ez-get-obj-addr obj)))
+ (ez-mem-set-byte (+ addr 6) new-child)))
+
+(defun ez-get-obj-plist-addr (obj)
+ (let ((addr (ez-get-obj-addr obj)))
+ (ez-mem-ref-word (+ addr 7))))
+
+(defun ez-get-obj-name (obj)
+ (let ((plist-addr (ez-get-obj-plist-addr obj)))
+ (if (> (ez-mem-ref-byte plist-addr) 0)
+ (ez-get-zstring (+ 1 (ez-get-obj-plist-addr obj)))
+ nil)))
+
+(defun ez-get-prop-default (prop)
+ (ez-mem-ref-word (+ ez-objtab-addr (* 2 (+ 1 prop)))))
+
+(defun ez-get-prop-len (prop-size-byte)
+ (lsh prop-size-byte -5))
+
+(defun ez-get-prop-num (prop-size-byte)
+ (logand #b00011111 prop-size-byte))
+
+(defun ez-get-obj-prop-addr (obj prop)
+ (let* ((plist-addr (ez-get-obj-plist-addr obj))
+ (prop-addr (+ plist-addr 1 (* 2 (ez-mem-ref-byte plist-addr))))
+ (size-byte (ez-mem-ref-byte prop-addr)))
+ (while (not (or (= size-byte 0)
+ (= prop (ez-get-prop-num size-byte))))
+ (setq prop-addr (+ prop-addr (ez-get-prop-len size-byte) 2)
+ size-byte (ez-mem-ref-byte prop-addr)))
+ prop-addr))
+
+(defun ez-get-obj-prop (obj prop)
+ (let* ((prop-addr (ez-get-obj-prop-addr obj prop))
+ (size-byte (ez-mem-ref-byte prop-addr)))
+ (if (= size-byte 0)
+ (ez-get-prop-default prop)
+ (let ((prop-len (ez-get-prop-len size-byte))
+ (data-addr (+ prop-addr 1)))
+ (cond
+ ((= prop-len 0)
+ (ez-mem-ref-byte data-addr))
+ ((>= prop-len 1)
+ (ez-mem-ref-word data-addr)))))))
+
+(defun ez-set-obj-prop (obj prop value)
+ (let* ((prop-addr (ez-get-obj-prop-addr obj prop))
+ (size-byte (ez-mem-ref-byte prop-addr)))
+ (cond
+ ((= size-byte 0)
+ (error "Tried to set non-existant property"))
+ ((= (ez-get-prop-len size-byte) 1)
+ (ez-mem-set-byte (+ prop-addr 1) value))
+ (t
+ (ez-mem-set-word (+ prop-addr 1) value)))))
+
+(defun ez-get-obj-attr (obj attr)
+ (let* ((byte-num (/ attr 8))
+ (bit-num (mod attr 8))
+ (bit-mask (lsh 1 (- 7 bit-num))))
+ (if (> (logand bit-mask (ez-mem-ref-byte (+ (ez-get-obj-addr obj) byte-num))) 0)
+ 1
+ 0)))
+
+(defun ez-set-obj-attr (obj attr val)
+ (let* ((byte-num (/ attr 8))
+ (bit-num (mod attr 8))
+ (bit-mask (lsh 1 (- 7 bit-num)))
+ (byte-addr (+ (ez-get-obj-addr obj) byte-num))
+ (byte (ez-mem-ref-byte byte-addr))
+ (current-set (> (logand bit-mask byte) 0)))
+ (if (or (and current-set (= val 0))
+ (and (not current-set) (> val 0)))
+ (ez-mem-set-byte byte-addr (logxor byte bit-mask)))))
+
+
+(defun ez-remove-obj (obj)
+ (let ((parent (ez-get-obj-parent obj))
+ (sibling (ez-get-obj-sibling obj)))
+ (unless (= parent 0)
+ (let ((child (ez-get-obj-child parent)))
+ (if (= child obj)
+ (ez-set-obj-child parent sibling)
+ (while (not (= obj (ez-get-obj-sibling child)))
+ (setq child (ez-get-obj-sibling child)))
+ (ez-set-obj-sibling child (ez-get-obj-sibling obj))))
+ (ez-set-obj-parent obj 0))
+ (ez-set-obj-sibling obj 0)))
+
+(defun ez-insert-obj (obj new-parent)
+ (ez-remove-obj obj)
+ (unless (= new-parent 0)
+ (ez-set-obj-sibling obj (ez-get-obj-child new-parent))
+ (ez-set-obj-child new-parent obj)))