;;; Commentary:
-;; An AVL tree is a nearly-perfect balanced binary tree. A tree
-;; consists of two cons cells, the first one holding the tag
-;; 'AVL-TREE in the car cell, and the second one having the tree
-;; in the car and the compare function in the cdr cell. The tree has
-;; a dummy node as its root with the real tree in the left pointer.
+;; An AVL tree is a nearly-perfect balanced binary tree. A tree consists of
+;; two elements, the root node and the compare function. The actual tree
+;; has a dummy node as its root with the real root in the left pointer.
;;
;; Each node of the tree consists of one data element, one left
;; sub-tree and one right sub-tree. Each node also has a balance
;; count, which is the difference in depth of the left and right
;; sub-trees.
;;
-;; The "public" functions (prefixed with "avl-tree") are:
-;; -create, -p, -compare-function, -empty, -enter, -delete,
-;; -member, -map, -first, -last, -copy, -flatten, -size, -clear.
+;; The functions with names of the form "avl-tree--" are intended for
+;; internal use only.
;;; Code:
-;;; ================================================================
-;;; Functions and macros handling an AVL tree node.
-
-(defmacro avl-tree-node-create (left right data balance)
- ;; Create and return an avl-tree node.
- `(vector ,left ,right ,data ,balance))
-
-(defmacro avl-tree-node-left (node)
- ;; Return the left pointer of NODE.
- `(aref ,node 0))
-
-(defmacro avl-tree-node-right (node)
- ;; Return the right pointer of NODE.
- `(aref ,node 1))
-
-(defmacro avl-tree-node-data (node)
- ;; Return the data of NODE.
- `(aref ,node 2))
-
-(defmacro avl-tree-node-set-left (node newleft)
- ;; Set the left pointer of NODE to NEWLEFT.
- `(aset ,node 0 ,newleft))
-
-(defmacro avl-tree-node-set-right (node newright)
- ;; Set the right pointer of NODE to NEWRIGHT.
- `(aset ,node 1 ,newright))
-
-(defmacro avl-tree-node-set-data (node newdata)
- ;; Set the data of NODE to NEWDATA.
- `(aset ,node 2 ,newdata))
-
-(defmacro avl-tree-node-branch (node branch)
+(eval-when-compile (require 'cl))
+
+;; ================================================================
+;;; Functions and macros handling an AVL tree node.
+
+(defstruct (avl-tree--node
+ ;; We force a representation without tag so it matches the
+ ;; pre-defstruct representation. Also we use the underlying
+ ;; representation in the implementation of avl-tree--node-branch.
+ (:type vector)
+ (:constructor nil)
+ (:constructor avl-tree--node-create (left right data balance))
+ (:copier nil))
+ left right data balance)
+
+(defalias 'avl-tree--node-branch 'aref
+ ;; This implementation is efficient but breaks the defstruct abstraction.
+ ;; An alternative could be
+ ;; (funcall (aref [avl-tree-left avl-tree-right avl-tree-data] branch) node)
"Get value of a branch of a node.
NODE is the node, and BRANCH is the branch.
-0 for left pointer, 1 for right pointer and 2 for the data.\""
- `(aref ,node ,branch))
-
-(defmacro avl-tree-node-set-branch (node branch newval)
- "Set value of a branch of a node.
-
-NODE is the node, and BRANCH is the branch.
-0 for left pointer, 1 for the right pointer and 2 for the data.
-NEWVAL is new value of the branch.\""
- `(aset ,node ,branch ,newval))
-
-(defmacro avl-tree-node-balance (node)
- ;; Return the balance field of a node.
- `(aref ,node 3))
-
-(defmacro avl-tree-node-set-balance (node newbal)
- ;; Set the balance field of a node.
- `(aset ,node 3 ,newbal))
+0 for left pointer, 1 for right pointer and 2 for the data.\"
+\(fn node branch)")
+;; The funcall/aref trick doesn't work for the setf method, unless we try
+;; and access the underlying setter function, but this wouldn't be
+;; portable either.
+(defsetf avl-tree--node-branch aset)
\f
-;;; ================================================================
-;;; Internal functions for use in the AVL tree package
-
-(defmacro avl-tree-root (tree)
+;; ================================================================
+;;; Internal functions for use in the AVL tree package
+
+(defstruct (avl-tree-
+ ;; A tagged list is the pre-defstruct representation.
+ ;; (:type list)
+ :named
+ (:constructor nil)
+ (:constructor avl-tree-create (cmpfun))
+ (:predicate avl-tree-p)
+ (:copier nil))
+ (dummyroot (avl-tree--node-create nil nil nil 0))
+ cmpfun)
+
+(defmacro avl-tree--root (tree)
;; Return the root node for an avl-tree. INTERNAL USE ONLY.
- `(avl-tree-node-left (car (cdr ,tree))))
-
-(defmacro avl-tree-dummyroot (tree)
- ;; Return the dummy node of an avl-tree. INTERNAL USE ONLY.
- `(car (cdr ,tree)))
-
-(defmacro avl-tree-cmpfun (tree)
- ;; Return the compare function of AVL tree TREE. INTERNAL USE ONLY.
- `(cdr (cdr ,tree)))
+ `(avl-tree--node-left (avl-tree--dummyroot tree)))
+(defsetf avl-tree--root (tree) (node)
+ `(setf (avl-tree--node-left (avl-tree--dummyroot ,tree)) ,node))
;; ----------------------------------------------------------------
;; Deleting data
-(defun avl-tree-del-balance1 (node branch)
+(defun avl-tree--del-balance1 (node branch)
;; Rebalance a tree and return t if the height of the tree has shrunk.
- (let ((br (avl-tree-node-branch node branch))
+ (let ((br (avl-tree--node-branch node branch))
p1 b1 p2 b2 result)
(cond
- ((< (avl-tree-node-balance br) 0)
- (avl-tree-node-set-balance br 0)
+ ((< (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance br) 0)
t)
- ((= (avl-tree-node-balance br) 0)
- (avl-tree-node-set-balance br +1)
+ ((= (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance br) +1)
nil)
(t
;; Rebalance.
- (setq p1 (avl-tree-node-right br)
- b1 (avl-tree-node-balance p1))
+ (setq p1 (avl-tree--node-right br)
+ b1 (avl-tree--node-balance p1))
(if (>= b1 0)
;; Single RR rotation.
(progn
- (avl-tree-node-set-right br (avl-tree-node-left p1))
- (avl-tree-node-set-left p1 br)
+ (setf (avl-tree--node-right br) (avl-tree--node-left p1))
+ (setf (avl-tree--node-left p1) br)
(if (= 0 b1)
(progn
- (avl-tree-node-set-balance br +1)
- (avl-tree-node-set-balance p1 -1)
+ (setf (avl-tree--node-balance br) +1)
+ (setf (avl-tree--node-balance p1) -1)
(setq result nil))
- (avl-tree-node-set-balance br 0)
- (avl-tree-node-set-balance p1 0)
+ (setf (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance p1) 0)
(setq result t))
- (avl-tree-node-set-branch node branch p1)
+ (setf (avl-tree--node-branch node branch) p1)
result)
;; Double RL rotation.
- (setq p2 (avl-tree-node-left p1)
- b2 (avl-tree-node-balance p2))
- (avl-tree-node-set-left p1 (avl-tree-node-right p2))
- (avl-tree-node-set-right p2 p1)
- (avl-tree-node-set-right br (avl-tree-node-left p2))
- (avl-tree-node-set-left p2 br)
- (if (> b2 0)
- (avl-tree-node-set-balance br -1)
- (avl-tree-node-set-balance br 0))
- (if (< b2 0)
- (avl-tree-node-set-balance p1 +1)
- (avl-tree-node-set-balance p1 0))
- (avl-tree-node-set-branch node branch p2)
- (avl-tree-node-set-balance p2 0)
+ (setq p2 (avl-tree--node-left p1)
+ b2 (avl-tree--node-balance p2))
+ (setf (avl-tree--node-left p1) (avl-tree--node-right p2))
+ (setf (avl-tree--node-right p2) p1)
+ (setf (avl-tree--node-right br) (avl-tree--node-left p2))
+ (setf (avl-tree--node-left p2) br)
+ (setf (avl-tree--node-balance br) (if (> b2 0) -1 0))
+ (setf (avl-tree--node-balance p1) (if (< b2 0) +1 0))
+ (setf (avl-tree--node-branch node branch) p2)
+ (setf (avl-tree--node-balance p2) 0)
t)))))
-(defun avl-tree-del-balance2 (node branch)
- (let ((br (avl-tree-node-branch node branch))
+(defun avl-tree--del-balance2 (node branch)
+ (let ((br (avl-tree--node-branch node branch))
p1 b1 p2 b2 result)
(cond
- ((> (avl-tree-node-balance br) 0)
- (avl-tree-node-set-balance br 0)
+ ((> (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance br) 0)
t)
- ((= (avl-tree-node-balance br) 0)
- (avl-tree-node-set-balance br -1)
+ ((= (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance br) -1)
nil)
(t
;; Rebalance.
- (setq p1 (avl-tree-node-left br)
- b1 (avl-tree-node-balance p1))
+ (setq p1 (avl-tree--node-left br)
+ b1 (avl-tree--node-balance p1))
(if (<= b1 0)
;; Single LL rotation.
(progn
- (avl-tree-node-set-left br (avl-tree-node-right p1))
- (avl-tree-node-set-right p1 br)
+ (setf (avl-tree--node-left br) (avl-tree--node-right p1))
+ (setf (avl-tree--node-right p1) br)
(if (= 0 b1)
(progn
- (avl-tree-node-set-balance br -1)
- (avl-tree-node-set-balance p1 +1)
+ (setf (avl-tree--node-balance br) -1)
+ (setf (avl-tree--node-balance p1) +1)
(setq result nil))
- (avl-tree-node-set-balance br 0)
- (avl-tree-node-set-balance p1 0)
+ (setf (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance p1) 0)
(setq result t))
- (avl-tree-node-set-branch node branch p1)
+ (setf (avl-tree--node-branch node branch) p1)
result)
;; Double LR rotation.
- (setq p2 (avl-tree-node-right p1)
- b2 (avl-tree-node-balance p2))
- (avl-tree-node-set-right p1 (avl-tree-node-left p2))
- (avl-tree-node-set-left p2 p1)
- (avl-tree-node-set-left br (avl-tree-node-right p2))
- (avl-tree-node-set-right p2 br)
- (if (< b2 0)
- (avl-tree-node-set-balance br +1)
- (avl-tree-node-set-balance br 0))
- (if (> b2 0)
- (avl-tree-node-set-balance p1 -1)
- (avl-tree-node-set-balance p1 0))
- (avl-tree-node-set-branch node branch p2)
- (avl-tree-node-set-balance p2 0)
+ (setq p2 (avl-tree--node-right p1)
+ b2 (avl-tree--node-balance p2))
+ (setf (avl-tree--node-right p1) (avl-tree--node-left p2))
+ (setf (avl-tree--node-left p2) p1)
+ (setf (avl-tree--node-left br) (avl-tree--node-right p2))
+ (setf (avl-tree--node-right p2) br)
+ (setf (avl-tree--node-balance br) (if (< b2 0) +1 0))
+ (setf (avl-tree--node-balance p1) (if (> b2 0) -1 0))
+ (setf (avl-tree--node-branch node branch) p2)
+ (setf (avl-tree--node-balance p2) 0)
t)))))
-(defun avl-tree-do-del-internal (node branch q)
- (let ((br (avl-tree-node-branch node branch)))
- (if (avl-tree-node-right br)
- (if (avl-tree-do-del-internal br +1 q)
- (avl-tree-del-balance2 node branch))
- (avl-tree-node-set-data q (avl-tree-node-data br))
- (avl-tree-node-set-branch node branch
- (avl-tree-node-left br))
+(defun avl-tree--do-del-internal (node branch q)
+ (let ((br (avl-tree--node-branch node branch)))
+ (if (avl-tree--node-right br)
+ (if (avl-tree--do-del-internal br +1 q)
+ (avl-tree--del-balance2 node branch))
+ (setf (avl-tree--node-data q) (avl-tree--node-data br))
+ (setf (avl-tree--node-branch node branch)
+ (avl-tree--node-left br))
t)))
-(defun avl-tree-do-delete (cmpfun root branch data)
+(defun avl-tree--do-delete (cmpfun root branch data)
;; Return t if the height of the tree has shrunk.
- (let ((br (avl-tree-node-branch root branch)))
+ (let ((br (avl-tree--node-branch root branch)))
(cond
((null br)
nil)
- ((funcall cmpfun data (avl-tree-node-data br))
- (if (avl-tree-do-delete cmpfun br 0 data)
- (avl-tree-del-balance1 root branch)))
+ ((funcall cmpfun data (avl-tree--node-data br))
+ (if (avl-tree--do-delete cmpfun br 0 data)
+ (avl-tree--del-balance1 root branch)))
- ((funcall cmpfun (avl-tree-node-data br) data)
- (if (avl-tree-do-delete cmpfun br 1 data)
- (avl-tree-del-balance2 root branch)))
+ ((funcall cmpfun (avl-tree--node-data br) data)
+ (if (avl-tree--do-delete cmpfun br 1 data)
+ (avl-tree--del-balance2 root branch)))
(t
;; Found it. Let's delete it.
(cond
- ((null (avl-tree-node-right br))
- (avl-tree-node-set-branch root branch (avl-tree-node-left br))
+ ((null (avl-tree--node-right br))
+ (setf (avl-tree--node-branch root branch) (avl-tree--node-left br))
t)
- ((null (avl-tree-node-left br))
- (avl-tree-node-set-branch root branch (avl-tree-node-right br))
+ ((null (avl-tree--node-left br))
+ (setf (avl-tree--node-branch root branch) (avl-tree--node-right br))
t)
(t
- (if (avl-tree-do-del-internal br 0 br)
- (avl-tree-del-balance1 root branch))))))))
+ (if (avl-tree--do-del-internal br 0 br)
+ (avl-tree--del-balance1 root branch))))))))
;; ----------------------------------------------------------------
;; Entering data
-(defun avl-tree-enter-balance1 (node branch)
+(defun avl-tree--enter-balance1 (node branch)
;; Rebalance a tree and return t if the height of the tree has grown.
- (let ((br (avl-tree-node-branch node branch))
+ (let ((br (avl-tree--node-branch node branch))
p1 p2 b2 result)
(cond
- ((< (avl-tree-node-balance br) 0)
- (avl-tree-node-set-balance br 0)
+ ((< (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance br) 0)
nil)
- ((= (avl-tree-node-balance br) 0)
- (avl-tree-node-set-balance br +1)
+ ((= (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance br) +1)
t)
(t
;; Tree has grown => Rebalance.
- (setq p1 (avl-tree-node-right br))
- (if (> (avl-tree-node-balance p1) 0)
+ (setq p1 (avl-tree--node-right br))
+ (if (> (avl-tree--node-balance p1) 0)
;; Single RR rotation.
(progn
- (avl-tree-node-set-right br (avl-tree-node-left p1))
- (avl-tree-node-set-left p1 br)
- (avl-tree-node-set-balance br 0)
- (avl-tree-node-set-branch node branch p1))
+ (setf (avl-tree--node-right br) (avl-tree--node-left p1))
+ (setf (avl-tree--node-left p1) br)
+ (setf (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-branch node branch) p1))
;; Double RL rotation.
- (setq p2 (avl-tree-node-left p1)
- b2 (avl-tree-node-balance p2))
- (avl-tree-node-set-left p1 (avl-tree-node-right p2))
- (avl-tree-node-set-right p2 p1)
- (avl-tree-node-set-right br (avl-tree-node-left p2))
- (avl-tree-node-set-left p2 br)
- (if (> b2 0)
- (avl-tree-node-set-balance br -1)
- (avl-tree-node-set-balance br 0))
- (if (< b2 0)
- (avl-tree-node-set-balance p1 +1)
- (avl-tree-node-set-balance p1 0))
- (avl-tree-node-set-branch node branch p2))
- (avl-tree-node-set-balance (avl-tree-node-branch node branch) 0)
+ (setq p2 (avl-tree--node-left p1)
+ b2 (avl-tree--node-balance p2))
+ (setf (avl-tree--node-left p1) (avl-tree--node-right p2))
+ (setf (avl-tree--node-right p2) p1)
+ (setf (avl-tree--node-right br) (avl-tree--node-left p2))
+ (setf (avl-tree--node-left p2) br)
+ (setf (avl-tree--node-balance br) (if (> b2 0) -1 0))
+ (setf (avl-tree--node-balance p1) (if (< b2 0) +1 0))
+ (setf (avl-tree--node-branch node branch) p2))
+ (setf (avl-tree--node-balance (avl-tree--node-branch node branch)) 0)
nil))))
-(defun avl-tree-enter-balance2 (node branch)
+(defun avl-tree--enter-balance2 (node branch)
;; Return t if the tree has grown.
- (let ((br (avl-tree-node-branch node branch))
+ (let ((br (avl-tree--node-branch node branch))
p1 p2 b2)
(cond
- ((> (avl-tree-node-balance br) 0)
- (avl-tree-node-set-balance br 0)
+ ((> (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance br) 0)
nil)
- ((= (avl-tree-node-balance br) 0)
- (avl-tree-node-set-balance br -1)
+ ((= (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-balance br) -1)
t)
(t
;; Balance was -1 => Rebalance.
- (setq p1 (avl-tree-node-left br))
- (if (< (avl-tree-node-balance p1) 0)
+ (setq p1 (avl-tree--node-left br))
+ (if (< (avl-tree--node-balance p1) 0)
;; Single LL rotation.
(progn
- (avl-tree-node-set-left br (avl-tree-node-right p1))
- (avl-tree-node-set-right p1 br)
- (avl-tree-node-set-balance br 0)
- (avl-tree-node-set-branch node branch p1))
+ (setf (avl-tree--node-left br) (avl-tree--node-right p1))
+ (setf (avl-tree--node-right p1) br)
+ (setf (avl-tree--node-balance br) 0)
+ (setf (avl-tree--node-branch node branch) p1))
;; Double LR rotation.
- (setq p2 (avl-tree-node-right p1)
- b2 (avl-tree-node-balance p2))
- (avl-tree-node-set-right p1 (avl-tree-node-left p2))
- (avl-tree-node-set-left p2 p1)
- (avl-tree-node-set-left br (avl-tree-node-right p2))
- (avl-tree-node-set-right p2 br)
- (if (< b2 0)
- (avl-tree-node-set-balance br +1)
- (avl-tree-node-set-balance br 0))
- (if (> b2 0)
- (avl-tree-node-set-balance p1 -1)
- (avl-tree-node-set-balance p1 0))
- (avl-tree-node-set-branch node branch p2))
- (avl-tree-node-set-balance (avl-tree-node-branch node branch) 0)
+ (setq p2 (avl-tree--node-right p1)
+ b2 (avl-tree--node-balance p2))
+ (setf (avl-tree--node-right p1) (avl-tree--node-left p2))
+ (setf (avl-tree--node-left p2) p1)
+ (setf (avl-tree--node-left br) (avl-tree--node-right p2))
+ (setf (avl-tree--node-right p2) br)
+ (setf (avl-tree--node-balance br) (if (< b2 0) +1 0))
+ (setf (avl-tree--node-balance p1) (if (> b2 0) -1 0))
+ (setf (avl-tree--node-branch node branch) p2))
+ (setf (avl-tree--node-balance (avl-tree--node-branch node branch)) 0)
nil))))
-(defun avl-tree-do-enter (cmpfun root branch data)
+(defun avl-tree--do-enter (cmpfun root branch data)
;; Return t if height of tree ROOT has grown. INTERNAL USE ONLY.
- (let ((br (avl-tree-node-branch root branch)))
+ (let ((br (avl-tree--node-branch root branch)))
(cond
((null br)
;; Data not in tree, insert it.
- (avl-tree-node-set-branch
- root branch (avl-tree-node-create nil nil data 0))
+ (setf (avl-tree--node-branch root branch)
+ (avl-tree--node-create nil nil data 0))
t)
- ((funcall cmpfun data (avl-tree-node-data br))
- (and (avl-tree-do-enter cmpfun br 0 data)
- (avl-tree-enter-balance2 root branch)))
+ ((funcall cmpfun data (avl-tree--node-data br))
+ (and (avl-tree--do-enter cmpfun br 0 data)
+ (avl-tree--enter-balance2 root branch)))
- ((funcall cmpfun (avl-tree-node-data br) data)
- (and (avl-tree-do-enter cmpfun br 1 data)
- (avl-tree-enter-balance1 root branch)))
+ ((funcall cmpfun (avl-tree--node-data br) data)
+ (and (avl-tree--do-enter cmpfun br 1 data)
+ (avl-tree--enter-balance1 root branch)))
(t
- (avl-tree-node-set-data br data)
+ (setf (avl-tree--node-data br) data)
nil))))
;; ----------------------------------------------------------------
-(defun avl-tree-mapc (map-function root)
+(defun avl-tree--mapc (map-function root)
;; Apply MAP-FUNCTION to all nodes in the tree starting with ROOT.
;; The function is applied in-order.
;;
(push nil stack)
(while node
(if (and go-left
- (avl-tree-node-left node))
+ (avl-tree--node-left node))
;; Do the left subtree first.
(progn
(push node stack)
- (setq node (avl-tree-node-left node)))
+ (setq node (avl-tree--node-left node)))
;; Apply the function...
(funcall map-function node)
;; and do the right subtree.
- (if (avl-tree-node-right node)
- (setq node (avl-tree-node-right node)
- go-left t)
- (setq node (pop stack)
- go-left nil))))))
+ (setq node (if (setq go-left (avl-tree--node-right node))
+ (avl-tree--node-right node)
+ (pop stack)))))))
-(defun avl-tree-do-copy (root)
+(defun avl-tree--do-copy (root)
;; Copy the avl tree with ROOT as root.
;; Highly recursive. INTERNAL USE ONLY.
(if (null root)
nil
- (avl-tree-node-create
- (avl-tree-do-copy (avl-tree-node-left root))
- (avl-tree-do-copy (avl-tree-node-right root))
- (avl-tree-node-data root)
- (avl-tree-node-balance root))))
+ (avl-tree--node-create
+ (avl-tree--do-copy (avl-tree--node-left root))
+ (avl-tree--do-copy (avl-tree--node-right root))
+ (avl-tree--node-data root)
+ (avl-tree--node-balance root))))
\f
-;;; ================================================================
-;;; The public functions which operate on AVL trees.
-
-(defun avl-tree-create (compare-function)
- "Create a new empty avl tree and return it.
-COMPARE-FUNCTION is a function which takes two arguments, A and B,
-and returns non-nil if A is less than B, and nil otherwise."
- (cons 'AVL-TREE
- (cons (avl-tree-node-create nil nil nil 0)
- compare-function)))
+;; ================================================================
+;;; The public functions which operate on AVL trees.
-(defun avl-tree-p (obj)
- "Return t if OBJ is an avl tree, nil otherwise."
- (eq (car-safe obj) 'AVL-TREE))
+(defalias 'avl-tree-compare-function 'avl-tree--cmpfun
+ "Return the comparison function for the avl tree TREE.
-(defun avl-tree-compare-function (tree)
- "Return the comparison function for the avl tree TREE."
- (avl-tree-cmpfun tree))
+\(fn TREE)")
(defun avl-tree-empty (tree)
"Return t if avl tree TREE is emtpy, otherwise return nil."
- (null (avl-tree-root tree)))
+ (null (avl-tree--root tree)))
(defun avl-tree-enter (tree data)
"In the avl tree TREE insert DATA.
Return DATA."
- (avl-tree-do-enter (avl-tree-cmpfun tree)
- (avl-tree-dummyroot tree)
- 0
- data)
+ (avl-tree--do-enter (avl-tree--cmpfun tree)
+ (avl-tree--dummyroot tree)
+ 0
+ data)
data)
(defun avl-tree-delete (tree data)
"From the avl tree TREE, delete DATA.
Return the element in TREE which matched DATA,
nil if no element matched."
- (avl-tree-do-delete (avl-tree-cmpfun tree)
- (avl-tree-dummyroot tree)
- 0
- data))
+ (avl-tree--do-delete (avl-tree--cmpfun tree)
+ (avl-tree--dummyroot tree)
+ 0
+ data))
(defun avl-tree-member (tree data)
"Return the element in the avl tree TREE which matches DATA.
`avl-tree-create' when TREE was created.
If there is no such element in the tree, the value is nil."
- (let ((node (avl-tree-root tree))
- (compare-function (avl-tree-cmpfun tree))
+ (let ((node (avl-tree--root tree))
+ (compare-function (avl-tree--cmpfun tree))
found)
(while (and node
(not found))
(cond
- ((funcall compare-function data (avl-tree-node-data node))
- (setq node (avl-tree-node-left node)))
- ((funcall compare-function (avl-tree-node-data node) data)
- (setq node (avl-tree-node-right node)))
+ ((funcall compare-function data (avl-tree--node-data node))
+ (setq node (avl-tree--node-left node)))
+ ((funcall compare-function (avl-tree--node-data node) data)
+ (setq node (avl-tree--node-right node)))
(t
(setq found t))))
(if node
- (avl-tree-node-data node)
+ (avl-tree--node-data node)
nil)))
(defun avl-tree-map (__map-function__ tree)
"Apply __MAP-FUNCTION__ to all elements in the avl tree TREE."
- (avl-tree-mapc
- (function (lambda (node)
- (avl-tree-node-set-data
- node (funcall __map-function__
- (avl-tree-node-data node)))))
- (avl-tree-root tree)))
+ (avl-tree--mapc
+ (lambda (node)
+ (setf (avl-tree--node-data node)
+ (funcall __map-function__ (avl-tree--node-data node))))
+ (avl-tree--root tree)))
(defun avl-tree-first (tree)
"Return the first element in TREE, or nil if TREE is empty."
- (let ((node (avl-tree-root tree)))
- (if node
- (progn
- (while (avl-tree-node-left node)
- (setq node (avl-tree-node-left node)))
- (avl-tree-node-data node))
- nil)))
+ (let ((node (avl-tree--root tree)))
+ (when node
+ (while (avl-tree--node-left node)
+ (setq node (avl-tree--node-left node)))
+ (avl-tree--node-data node))))
(defun avl-tree-last (tree)
"Return the last element in TREE, or nil if TREE is empty."
- (let ((node (avl-tree-root tree)))
- (if node
- (progn
- (while (avl-tree-node-right node)
- (setq node (avl-tree-node-right node)))
- (avl-tree-node-data node))
- nil)))
+ (let ((node (avl-tree--root tree)))
+ (when node
+ (while (avl-tree--node-right node)
+ (setq node (avl-tree--node-right node)))
+ (avl-tree--node-data node))))
(defun avl-tree-copy (tree)
"Return a copy of the avl tree TREE."
- (let ((new-tree (avl-tree-create (avl-tree-cmpfun tree))))
- (avl-tree-node-set-left (avl-tree-dummyroot new-tree)
- (avl-tree-do-copy (avl-tree-root tree)))
+ (let ((new-tree (avl-tree-create (avl-tree--cmpfun tree))))
+ (setf (avl-tree--root new-tree) (avl-tree--do-copy (avl-tree--root tree)))
new-tree))
(defun avl-tree-flatten (tree)
"Return a sorted list containing all elements of TREE."
(nreverse
(let ((treelist nil))
- (avl-tree-mapc
- (function (lambda (node)
- (setq treelist (cons (avl-tree-node-data node)
- treelist))))
- (avl-tree-root tree))
+ (avl-tree--mapc
+ (lambda (node) (push (avl-tree--node-data node) treelist))
+ (avl-tree--root tree))
treelist)))
(defun avl-tree-size (tree)
"Return the number of elements in TREE."
(let ((treesize 0))
- (avl-tree-mapc
- (function (lambda (data)
- (setq treesize (1+ treesize))
- data))
- (avl-tree-root tree))
+ (avl-tree--mapc
+ (lambda (data) (setq treesize (1+ treesize)))
+ (avl-tree--root tree))
treesize))
(defun avl-tree-clear (tree)
"Clear the avl tree TREE."
- (avl-tree-node-set-left (avl-tree-dummyroot tree) nil))
+ (setf (avl-tree--root tree) nil))
(provide 'avl-tree)
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