-;;;; $Id: elib-node.el,v 0.8 1995/12/11 00:11:19 ceder Exp $
-;;;; Nodes used in binary trees and doubly linked lists.
+;;; avl-tree.el --- balanced binary trees, AVL-trees
-;; Copyright (C) 1991-1995 Free Software Foundation
+;; Copyright (C) 1995, 2007 Free Software Foundation, Inc.
;; Author: Per Cederqvist <ceder@lysator.liu.se>
;; Inge Wallin <inge@lysator.liu.se>
-;; Maintainer: elib-maintainers@lysator.liu.se
-;; Created: 20 May 1991
-;; Keywords: extensions, lisp
-
-;;;; This file is part of the GNU Emacs lisp library, Elib.
-;;;;
-;;;; GNU Elib is free software; you can redistribute it and/or modify
-;;;; it under the terms of the GNU General Public License as published by
-;;;; the Free Software Foundation; either version 2, or (at your option)
-;;;; any later version.
-;;;;
-;;;; GNU Elib is distributed in the hope that it will be useful,
-;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-;;;; GNU General Public License for more details.
-;;;;
-;;;; You should have received a copy of the GNU General Public License
-;;;; along with GNU Elib; see the file COPYING. If not, write to
-;;;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;;;; Boston, MA 02111-1307, USA
-;;;;
-;;;; Author: Inge Wallin
-;;;;
+;; Thomas Bellman <bellman@lysator.liu.se>
+;; Maintainer: FSF
+;; Created: 10 May 1991
+;; Keywords: extensions, data structures
-;;; Commentary:
+;; This file is part of GNU Emacs.
-;;; A node is implemented as an array with three elements, using
-;;; (elt node 0) as the left pointer
-;;; (elt node 1) as the right pointer
-;;; (elt node 2) as the data
-;;;
-;;; Some types of trees, e.g. AVL trees, need bigger nodes, but
-;;; as long as the first three parts are the left pointer, the
-;;; right pointer and the data field, these macros can be used.
-;;;
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
-;;; Code:
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
-;;; Begin HACKS to make avl-tree.el standalone.
-;;;
-;;; 0/ Don't do this.
-;;; (provide 'elib-node)
-;;;
-;;; End HACKS to make avl-tree.el standalone.
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING. If not, write to the
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
+;;; Commentary:
-(defmacro elib-node-create (left right data)
+;; This file combines elib-node.el and avltree.el from Elib.
+;;
+;; * Comments from elib-node.el
+;; A node is implemented as an array with three elements, using
+;; (elt node 0) as the left pointer
+;; (elt node 1) as the right pointer
+;; (elt node 2) as the data
+;;
+;; Some types of trees, e.g. AVL trees, need bigger nodes, but
+;; as long as the first three parts are the left pointer, the
+;; right pointer and the data field, these macros can be used.
+;;
+;; * Comments from avltree.el
+;; An AVL tree is a nearly-perfect balanced binary tree. A tree
+;; consists of two cons cells, the first one holding the tag
+;; 'AVLTREE 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.
+;;
+;; 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.
+;;; Code:
+
+(defmacro elib-node-create (left right data)
;; Create a tree node from LEFT, RIGHT and DATA.
(` (vector (, left) (, right) (, data))))
-
(defmacro elib-node-left (node)
-
;; Return the left pointer of NODE.
(` (aref (, node) 0)))
-
(defmacro elib-node-right (node)
-
;; Return the right pointer of NODE.
(` (aref (, node) 1)))
-
(defmacro elib-node-data (node)
-
;; Return the data of NODE.
(` (aref (, node) 2)))
-
(defmacro elib-node-set-left (node newleft)
-
;; Set the left pointer of NODE to NEWLEFT.
(` (aset (, node) 0 (, newleft))))
-
(defmacro elib-node-set-right (node newright)
-
;; Set the right pointer of NODE to NEWRIGHT.
(` (aset (, node) 1 (, newright))))
-
(defmacro elib-node-set-data (node newdata)
;; Set the data of NODE to NEWDATA.
(` (aset (, node) 2 (, newdata))))
-
-
(defmacro elib-node-branch (node branch)
-
;; 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 elib-node-set-branch (node branch newval)
-
;; Set value of a branch of a node.
;;
;; NODE is the node, and BRANCH is the branch.
;; NEWVAL is new value of the branch."
(` (aset (, node) (, branch) (, newval))))
-;;; elib-node.el ends here.
-;;;; $Id: avltree.el,v 0.8 1995/12/11 00:10:54 ceder Exp $
-;;;; This file implements balanced binary trees, AVL-trees.
-
-;; Copyright (C) 1991-1995 Free Software Foundation
-
-;; Author: Inge Wallin <inge@lysator.liu.se>
-;; Thomas Bellman <bellman@lysator.liu.se>
-;; Maintainer: elib-maintainers@lysator.liu.se
-;; Created: 10 May 1991
-;; Keywords: extensions, lisp
-
-;;;; This file is part of the GNU Emacs lisp library, Elib.
-;;;;
-;;;; GNU Elib is free software; you can redistribute it and/or modify
-;;;; it under the terms of the GNU General Public License as published by
-;;;; the Free Software Foundation; either version 2, or (at your option)
-;;;; any later version.
-;;;;
-;;;; GNU Elib is distributed in the hope that it will be useful,
-;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-;;;; GNU General Public License for more details.
-;;;;
-;;;; You should have received a copy of the GNU General Public License
-;;;; along with GNU Elib; see the file COPYING. If not, write to
-;;;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;;;; Boston, MA 02111-1307, USA
-;;;;
-;;;; Initial author: Thomas Bellman
-;;;; Lysator Computer Club
-;;;; Linkoping University
-;;;; Sweden
-;;;;
-;;;; Bugfixes and completion: Inge Wallin
-;;;;
-
-
-;;; Commentary:
-;;;
-;;; An AVL tree is a nearly-perfect balanced binary tree. A tree
-;;; consists of two cons cells, the first one holding the tag
-;;; 'AVLTREE 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.
-;;;
-;;; 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.
-;;;
-
-;;; Code:
-
-;;; Begin HACKS to make avl-tree.el standalone.
-;;;
-;;; 1/ See above for inlined elib-node.el.
-;;; (require 'elib-node)
-;;;
-;;; 2/ This requirement has been replaced w/ new code.
-;;; (require 'stack-m)
-;;;
-;;; 3/ New code:
(eval-when-compile (require 'cl))
(defun elib-stack-create () (list))
(defmacro elib-stack-push (stack object) `(push ,object ,stack))
(defmacro elib-stack-pop (stack) `(pop ,stack))
-;;;
-;;; 4/ Provide `avl-tree' instead of `avltree'.
(provide 'avl-tree)
-;;;
-;;; End HACKS to make avl-tree.el standalone.
-
;;; ================================================================
;;; Functions and macros handling an AVL tree node.
-;;
-;; The rest of the functions needed here can be found in
-;; elib-node.el.
-;;
-
-
(defmacro elib-avl-node-create (left right data balance)
-
;; Create and return an avl-tree node.
(` (vector (, left) (, right) (, data) (, balance))))
-
(defmacro elib-avl-node-balance (node)
-
;; Return the balance field of a node.
(` (aref (, node) 3)))
-
(defmacro elib-avl-node-set-balance (node newbal)
-
;; Set the balance field of a node.
(` (aset (, node) 3 (, newbal))))
-
\f
;;; ================================================================
;;; Internal functions for use in the AVL tree package
;;; The functions and macros in this section all start with `elib-avl-'.
;;;
-
(defmacro elib-avl-root (tree)
-
;; Return the root node for an avl-tree. INTERNAL USE ONLY.
(` (elib-node-left (car (cdr (, tree))))))
-
(defmacro elib-avl-dummyroot (tree)
-
;; Return the dummy node of an avl-tree. INTERNAL USE ONLY.
-
(` (car (cdr (, tree)))))
-
(defmacro elib-avl-cmpfun (tree)
-
;; Return the compare function of AVL tree TREE. INTERNAL USE ONLY.
(` (cdr (cdr (, tree)))))
-
;; ----------------------------------------------------------------
;; Deleting data
-
(defun elib-avl-del-balance1 (node branch)
-
;; Rebalance a tree and return t if the height of the tree has shrunk.
(let* ((br (elib-node-branch node branch))
- p1
- b1
- p2
- b2
- result)
+ p1
+ b1
+ p2
+ b2
+ result)
(cond
((< (elib-avl-node-balance br) 0)
(elib-avl-node-set-balance br 0)
(elib-avl-node-set-balance br +1)
nil)
- (t ; Rebalance
+ (t
+ ;; Rebalance.
(setq p1 (elib-node-right br)
- b1 (elib-avl-node-balance p1))
+ b1 (elib-avl-node-balance p1))
(if (>= b1 0)
- ;; Single RR rotation
- (progn
- (elib-node-set-right br (elib-node-left p1))
- (elib-node-set-left p1 br)
- (if (= 0 b1)
- (progn
- (elib-avl-node-set-balance br +1)
- (elib-avl-node-set-balance p1 -1)
- (setq result nil))
- (elib-avl-node-set-balance br 0)
- (elib-avl-node-set-balance p1 0)
- (setq result t))
- (elib-node-set-branch node branch p1)
- result)
-
- ;; Double RL rotation
- (setq p2 (elib-node-left p1)
- b2 (elib-avl-node-balance p2))
- (elib-node-set-left p1 (elib-node-right p2))
- (elib-node-set-right p2 p1)
- (elib-node-set-right br (elib-node-left p2))
- (elib-node-set-left p2 br)
- (if (> b2 0)
- (elib-avl-node-set-balance br -1)
- (elib-avl-node-set-balance br 0))
- (if (< b2 0)
- (elib-avl-node-set-balance p1 +1)
- (elib-avl-node-set-balance p1 0))
- (elib-node-set-branch node branch p2)
- (elib-avl-node-set-balance p2 0)
- t)
- ))
- ))
-
+ ;; Single RR rotation.
+ (progn
+ (elib-node-set-right br (elib-node-left p1))
+ (elib-node-set-left p1 br)
+ (if (= 0 b1)
+ (progn
+ (elib-avl-node-set-balance br +1)
+ (elib-avl-node-set-balance p1 -1)
+ (setq result nil))
+ (elib-avl-node-set-balance br 0)
+ (elib-avl-node-set-balance p1 0)
+ (setq result t))
+ (elib-node-set-branch node branch p1)
+ result)
+
+ ;; Double RL rotation.
+ (setq p2 (elib-node-left p1)
+ b2 (elib-avl-node-balance p2))
+ (elib-node-set-left p1 (elib-node-right p2))
+ (elib-node-set-right p2 p1)
+ (elib-node-set-right br (elib-node-left p2))
+ (elib-node-set-left p2 br)
+ (if (> b2 0)
+ (elib-avl-node-set-balance br -1)
+ (elib-avl-node-set-balance br 0))
+ (if (< b2 0)
+ (elib-avl-node-set-balance p1 +1)
+ (elib-avl-node-set-balance p1 0))
+ (elib-node-set-branch node branch p2)
+ (elib-avl-node-set-balance p2 0)
+ t)))))
(defun elib-avl-del-balance2 (node branch)
-
(let* ((br (elib-node-branch node branch))
- p1
- b1
- p2
- b2
- result)
+ p1
+ b1
+ p2
+ b2
+ result)
(cond
((> (elib-avl-node-balance br) 0)
(elib-avl-node-set-balance br 0)
(elib-avl-node-set-balance br -1)
nil)
- (t ; Rebalance
+ (t
+ ;; Rebalance.
(setq p1 (elib-node-left br)
- b1 (elib-avl-node-balance p1))
+ b1 (elib-avl-node-balance p1))
(if (<= b1 0)
- ;; Single LL rotation
- (progn
- (elib-node-set-left br (elib-node-right p1))
- (elib-node-set-right p1 br)
- (if (= 0 b1)
- (progn
- (elib-avl-node-set-balance br -1)
- (elib-avl-node-set-balance p1 +1)
- (setq result nil))
- (elib-avl-node-set-balance br 0)
- (elib-avl-node-set-balance p1 0)
- (setq result t))
- (elib-node-set-branch node branch p1)
- result)
-
- ;; Double LR rotation
- (setq p2 (elib-node-right p1)
- b2 (elib-avl-node-balance p2))
- (elib-node-set-right p1 (elib-node-left p2))
- (elib-node-set-left p2 p1)
- (elib-node-set-left br (elib-node-right p2))
- (elib-node-set-right p2 br)
- (if (< b2 0)
- (elib-avl-node-set-balance br +1)
- (elib-avl-node-set-balance br 0))
- (if (> b2 0)
- (elib-avl-node-set-balance p1 -1)
- (elib-avl-node-set-balance p1 0))
- (elib-node-set-branch node branch p2)
- (elib-avl-node-set-balance p2 0)
- t)
- ))
- ))
-
+ ;; Single LL rotation.
+ (progn
+ (elib-node-set-left br (elib-node-right p1))
+ (elib-node-set-right p1 br)
+ (if (= 0 b1)
+ (progn
+ (elib-avl-node-set-balance br -1)
+ (elib-avl-node-set-balance p1 +1)
+ (setq result nil))
+ (elib-avl-node-set-balance br 0)
+ (elib-avl-node-set-balance p1 0)
+ (setq result t))
+ (elib-node-set-branch node branch p1)
+ result)
+
+ ;; Double LR rotation.
+ (setq p2 (elib-node-right p1)
+ b2 (elib-avl-node-balance p2))
+ (elib-node-set-right p1 (elib-node-left p2))
+ (elib-node-set-left p2 p1)
+ (elib-node-set-left br (elib-node-right p2))
+ (elib-node-set-right p2 br)
+ (if (< b2 0)
+ (elib-avl-node-set-balance br +1)
+ (elib-avl-node-set-balance br 0))
+ (if (> b2 0)
+ (elib-avl-node-set-balance p1 -1)
+ (elib-avl-node-set-balance p1 0))
+ (elib-node-set-branch node branch p2)
+ (elib-avl-node-set-balance p2 0)
+ t)))))
(defun elib-avl-do-del-internal (node branch q)
(let* ((br (elib-node-branch node branch)))
- (if (elib-node-right br)
- (if (elib-avl-do-del-internal br +1 q)
- (elib-avl-del-balance2 node branch))
- (elib-node-set-data q (elib-node-data br))
- (elib-node-set-branch node branch
- (elib-node-left br))
- t)))
-
-
+ (if (elib-node-right br)
+ (if (elib-avl-do-del-internal br +1 q)
+ (elib-avl-del-balance2 node branch))
+ (elib-node-set-data q (elib-node-data br))
+ (elib-node-set-branch node branch
+ (elib-node-left br))
+ t)))
(defun elib-avl-do-delete (cmpfun root branch data)
-
;; Return t if the height of the tree has shrunk.
(let* ((br (elib-node-branch root branch)))
(cond
((funcall cmpfun data (elib-node-data br))
(if (elib-avl-do-delete cmpfun br 0 data)
- (elib-avl-del-balance1 root branch)))
+ (elib-avl-del-balance1 root branch)))
((funcall cmpfun (elib-node-data br) data)
(if (elib-avl-do-delete cmpfun br 1 data)
- (elib-avl-del-balance2 root branch)))
+ (elib-avl-del-balance2 root branch)))
(t
;; Found it. Let's delete it.
(cond
((null (elib-node-right br))
- (elib-node-set-branch root branch (elib-node-left br))
- t)
+ (elib-node-set-branch root branch (elib-node-left br))
+ t)
((null (elib-node-left br))
- (elib-node-set-branch root branch (elib-node-right br))
- t)
+ (elib-node-set-branch root branch (elib-node-right br))
+ t)
(t
- (if (elib-avl-do-del-internal br 0 br)
- (elib-avl-del-balance1 root branch)))))
- )))
-
+ (if (elib-avl-do-del-internal br 0 br)
+ (elib-avl-del-balance1 root branch))))))))
;; ----------------------------------------------------------------
;; Entering data
-
-
(defun elib-avl-enter-balance1 (node branch)
-
;; Rebalance a tree and return t if the height of the tree has grown.
(let* ((br (elib-node-branch node branch))
- p1
- p2
- b2
- result)
+ p1
+ p2
+ b2
+ result)
(cond
((< (elib-avl-node-balance br) 0)
(elib-avl-node-set-balance br 0)
t)
(t
- ;; Tree has grown => Rebalance
+ ;; Tree has grown => Rebalance.
(setq p1 (elib-node-right br))
(if (> (elib-avl-node-balance p1) 0)
- ;; Single RR rotation
- (progn
- (elib-node-set-right br (elib-node-left p1))
- (elib-node-set-left p1 br)
- (elib-avl-node-set-balance br 0)
- (elib-node-set-branch node branch p1))
-
- ;; Double RL rotation
- (setq p2 (elib-node-left p1)
- b2 (elib-avl-node-balance p2))
- (elib-node-set-left p1 (elib-node-right p2))
- (elib-node-set-right p2 p1)
- (elib-node-set-right br (elib-node-left p2))
- (elib-node-set-left p2 br)
- (if (> b2 0)
- (elib-avl-node-set-balance br -1)
- (elib-avl-node-set-balance br 0))
- (if (< b2 0)
- (elib-avl-node-set-balance p1 +1)
- (elib-avl-node-set-balance p1 0))
- (elib-node-set-branch node branch p2))
+ ;; Single RR rotation.
+ (progn
+ (elib-node-set-right br (elib-node-left p1))
+ (elib-node-set-left p1 br)
+ (elib-avl-node-set-balance br 0)
+ (elib-node-set-branch node branch p1))
+
+ ;; Double RL rotation.
+ (setq p2 (elib-node-left p1)
+ b2 (elib-avl-node-balance p2))
+ (elib-node-set-left p1 (elib-node-right p2))
+ (elib-node-set-right p2 p1)
+ (elib-node-set-right br (elib-node-left p2))
+ (elib-node-set-left p2 br)
+ (if (> b2 0)
+ (elib-avl-node-set-balance br -1)
+ (elib-avl-node-set-balance br 0))
+ (if (< b2 0)
+ (elib-avl-node-set-balance p1 +1)
+ (elib-avl-node-set-balance p1 0))
+ (elib-node-set-branch node branch p2))
(elib-avl-node-set-balance (elib-node-branch node branch) 0)
- nil))
- ))
-
+ nil))))
(defun elib-avl-enter-balance2 (node branch)
-
;; Return t if the tree has grown.
(let* ((br (elib-node-branch node branch))
- p1
- p2
- b2)
+ p1
+ p2
+ b2)
(cond
((> (elib-avl-node-balance br) 0)
(elib-avl-node-set-balance br 0)
t)
(t
- ;; Balance was -1 => Rebalance
+ ;; Balance was -1 => Rebalance.
(setq p1 (elib-node-left br))
(if (< (elib-avl-node-balance p1) 0)
- ;; Single LL rotation
- (progn
- (elib-node-set-left br (elib-node-right p1))
- (elib-node-set-right p1 br)
- (elib-avl-node-set-balance br 0)
- (elib-node-set-branch node branch p1))
-
- ;; Double LR rotation
- (setq p2 (elib-node-right p1)
- b2 (elib-avl-node-balance p2))
- (elib-node-set-right p1 (elib-node-left p2))
- (elib-node-set-left p2 p1)
- (elib-node-set-left br (elib-node-right p2))
- (elib-node-set-right p2 br)
- (if (< b2 0)
- (elib-avl-node-set-balance br +1)
- (elib-avl-node-set-balance br 0))
- (if (> b2 0)
- (elib-avl-node-set-balance p1 -1)
- (elib-avl-node-set-balance p1 0))
- (elib-node-set-branch node branch p2))
+ ;; Single LL rotation.
+ (progn
+ (elib-node-set-left br (elib-node-right p1))
+ (elib-node-set-right p1 br)
+ (elib-avl-node-set-balance br 0)
+ (elib-node-set-branch node branch p1))
+
+ ;; Double LR rotation.
+ (setq p2 (elib-node-right p1)
+ b2 (elib-avl-node-balance p2))
+ (elib-node-set-right p1 (elib-node-left p2))
+ (elib-node-set-left p2 p1)
+ (elib-node-set-left br (elib-node-right p2))
+ (elib-node-set-right p2 br)
+ (if (< b2 0)
+ (elib-avl-node-set-balance br +1)
+ (elib-avl-node-set-balance br 0))
+ (if (> b2 0)
+ (elib-avl-node-set-balance p1 -1)
+ (elib-avl-node-set-balance p1 0))
+ (elib-node-set-branch node branch p2))
(elib-avl-node-set-balance (elib-node-branch node branch) 0)
- nil))
- ))
-
+ nil))))
(defun elib-avl-do-enter (cmpfun root branch data)
-
;; Return t if height of tree ROOT has grown. INTERNAL USE ONLY.
(let ((br (elib-node-branch root branch)))
(cond
((null br)
- ;; Data not in tree, insert it
+ ;; Data not in tree, insert it.
(elib-node-set-branch root branch
- (elib-avl-node-create nil nil data 0))
+ (elib-avl-node-create nil nil data 0))
t)
((funcall cmpfun data (elib-node-data br))
(and (elib-avl-do-enter cmpfun
- br
- 0 data)
- (elib-avl-enter-balance2 root branch)))
+ br
+ 0 data)
+ (elib-avl-enter-balance2 root branch)))
((funcall cmpfun (elib-node-data br) data)
(and (elib-avl-do-enter cmpfun
- br
- 1 data)
- (elib-avl-enter-balance1 root branch)))
+ br
+ 1 data)
+ (elib-avl-enter-balance1 root branch)))
(t
(elib-node-set-data br data)
nil))))
-
;; ----------------------------------------------------------------
-
(defun elib-avl-mapc (map-function root)
;; Apply MAP-FUNCTION to all nodes in the tree starting with ROOT.
;; The function is applied in-order.
;;
;; Note: MAP-FUNCTION is applied to the node and not to the data itself.
;; INTERNAL USE ONLY.
-
(let ((node root)
- (stack (elib-stack-create))
- (go-left t))
+ (stack (elib-stack-create))
+ (go-left t))
(elib-stack-push stack nil)
(while node
(if (and go-left
- (elib-node-left node))
- (progn ; Do the left subtree first.
- (elib-stack-push stack node)
- (setq node (elib-node-left node)))
- (funcall map-function node) ; Apply the function...
- (if (elib-node-right node) ; and do the right subtree.
- (setq node (elib-node-right node)
- go-left t)
- (setq node (elib-stack-pop stack)
- go-left nil))))))
-
+ (elib-node-left node))
+ ;; Do the left subtree first.
+ (progn
+ (elib-stack-push stack node)
+ (setq node (elib-node-left node)))
+ ;; Apply the function...
+ (funcall map-function node)
+ ;; and do the right subtree.
+ (if (elib-node-right node)
+ (setq node (elib-node-right node)
+ go-left t)
+ (setq node (elib-stack-pop stack)
+ go-left nil))))))
(defun elib-avl-do-copy (root)
;; Copy the tree with ROOT as root.
(if (null root)
nil
(elib-avl-node-create (elib-avl-do-copy (elib-node-left root))
- (elib-avl-do-copy (elib-node-right root))
- (elib-node-data root)
- (elib-avl-node-balance root))))
-
+ (elib-avl-do-copy (elib-node-right root))
+ (elib-node-data root)
+ (elib-avl-node-balance root))))
\f
;;; ================================================================
;;; The public functions which operate on AVL trees.
-
(defun avltree-create (compare-function)
"Create an empty avl tree.
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 'AVLTREE
- (cons (elib-avl-node-create nil nil nil 0)
- compare-function)))
-
+ (cons (elib-avl-node-create nil nil nil 0)
+ compare-function)))
(defun avltree-p (obj)
"Return t if OBJ is an avl tree, nil otherwise."
(eq (car-safe obj) 'AVLTREE))
-
(defun avltree-compare-function (tree)
"Return the comparision function for the avl tree TREE."
(elib-avl-cmpfun tree))
-
(defun avltree-empty (tree)
"Return t if TREE is emtpy, otherwise return nil."
(null (elib-avl-root tree)))
-
(defun avltree-enter (tree data)
"In the avl tree TREE insert DATA.
Return DATA."
-
(elib-avl-do-enter (elib-avl-cmpfun tree)
- (elib-avl-dummyroot tree)
- 0
- data)
+ (elib-avl-dummyroot tree)
+ 0
+ data)
data)
-
(defun avltree-delete (tree data)
"From the avl tree TREE, delete DATA.
Return the element in TREE which matched DATA, nil if no element matched."
-
(elib-avl-do-delete (elib-avl-cmpfun tree)
- (elib-avl-dummyroot tree)
- 0
- data))
-
+ (elib-avl-dummyroot tree)
+ 0
+ data))
(defun avltree-member (tree data)
"Return the element in the avl tree TREE which matches DATA.
when TREE was created.
If there is no such element in the tree, the value is nil."
-
(let ((node (elib-avl-root tree))
- (compare-function (elib-avl-cmpfun tree))
- found)
+ (compare-function (elib-avl-cmpfun tree))
+ found)
(while (and node
- (not found))
+ (not found))
(cond
((funcall compare-function data (elib-node-data node))
- (setq node (elib-node-left node)))
+ (setq node (elib-node-left node)))
((funcall compare-function (elib-node-data node) data)
- (setq node (elib-node-right node)))
+ (setq node (elib-node-right node)))
(t
- (setq found t))))
+ (setq found t))))
(if node
- (elib-node-data node)
+ (elib-node-data node)
nil)))
-
-
(defun avltree-map (__map-function__ tree)
"Apply MAP-FUNCTION to all elements in the avl tree TREE."
(elib-avl-mapc
(function (lambda (node)
- (elib-node-set-data node
- (funcall __map-function__
- (elib-node-data node)))))
+ (elib-node-set-data node
+ (funcall __map-function__
+ (elib-node-data node)))))
(elib-avl-root tree)))
-
-
(defun avltree-first (tree)
"Return the first element in TREE, or nil if TREE is empty."
-
(let ((node (elib-avl-root tree)))
(if node
- (progn
- (while (elib-node-left node)
- (setq node (elib-node-left node)))
- (elib-node-data node))
+ (progn
+ (while (elib-node-left node)
+ (setq node (elib-node-left node)))
+ (elib-node-data node))
nil)))
-
(defun avltree-last (tree)
"Return the last element in TREE, or nil if TREE is empty."
(let ((node (elib-avl-root tree)))
(if node
- (progn
- (while (elib-node-right node)
- (setq node (elib-node-right node)))
- (elib-node-data node))
+ (progn
+ (while (elib-node-right node)
+ (setq node (elib-node-right node)))
+ (elib-node-data node))
nil)))
-
(defun avltree-copy (tree)
"Return a copy of the avl tree TREE."
(let ((new-tree (avltree-create
- (elib-avl-cmpfun tree))))
+ (elib-avl-cmpfun tree))))
(elib-node-set-left (elib-avl-dummyroot new-tree)
- (elib-avl-do-copy (elib-avl-root tree)))
+ (elib-avl-do-copy (elib-avl-root tree)))
new-tree))
-
(defun avltree-flatten (tree)
"Return a sorted list containing all elements of TREE."
(nreverse
(let ((treelist nil))
(elib-avl-mapc (function (lambda (node)
- (setq treelist (cons (elib-node-data node)
- treelist))))
- (elib-avl-root tree))
+ (setq treelist (cons (elib-node-data node)
+ treelist))))
+ (elib-avl-root tree))
treelist)))
-
(defun avltree-size (tree)
"Return the number of elements in TREE."
(let ((treesize 0))
(elib-avl-mapc (function (lambda (data)
- (setq treesize (1+ treesize))
- data))
- (elib-avl-root tree))
+ (setq treesize (1+ treesize))
+ data))
+ (elib-avl-root tree))
treesize))
-
(defun avltree-clear (tree)
"Clear the avl tree TREE."
(elib-node-set-left (elib-avl-dummyroot tree) nil))
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