90 lines
2.6 KiB
EmacsLisp
90 lines
2.6 KiB
EmacsLisp
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;;;; elib-node.el,v 1.2 1992/04/07 20:49:16 berliner Exp
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;;;; This file implements the nodes used in binary trees and
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;;;; doubly linked lists
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;;;;
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;;;; Copyright (C) 1991 Inge Wallin
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;;;;
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;;;; This file is part of the GNU Emacs lisp library, Elib.
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;;;;
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;;;; GNU Elib is free software; you can redistribute it and/or modify
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;;;; it under the terms of the GNU General Public License as published by
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;;;; the Free Software Foundation; either version 1, or (at your option)
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;;;; any later version.
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;;;;
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;;;; GNU Elib is distributed in the hope that it will be useful,
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;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;;; GNU General Public License for more details.
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;;;;
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;;;; You should have received a copy of the GNU General Public License
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;;;; along with GNU Emacs; see the file COPYING. If not, write to
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;;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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;;;;
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;;;; Author: Inge Wallin
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;;;;
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;;;
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;;; A node is implemented as an array with three elements, using
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;;; (elt node 0) as the left pointer
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;;; (elt node 1) as the right pointer
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;;; (elt node 2) as the data
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;;;
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;;; Some types of trees, e.g. AVL trees, need bigger nodes, but
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;;; as long as the first three parts are the left pointer, the
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;;; right pointer and the data field, these macros can be used.
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;;;
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(provide 'elib-node)
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(defmacro elib-node-create (left right data)
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"Create a tree node from LEFT, RIGHT and DATA."
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(` (vector (, left) (, right) (, data))))
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(defmacro elib-node-left (node)
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"Return the left pointer of NODE."
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(` (aref (, node) 0)))
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(defmacro elib-node-right (node)
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"Return the right pointer of NODE."
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(` (aref (, node) 1)))
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(defmacro elib-node-data (node)
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"Return the data of NODE."
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(` (aref (, node) 2)))
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(defmacro elib-node-set-left (node newleft)
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"Set the left pointer of NODE to NEWLEFT."
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(` (aset (, node) 0 (, newleft))))
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(defmacro elib-node-set-right (node newright)
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"Set the right pointer of NODE to NEWRIGHT."
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(` (aset (, node) 1 (, newright))))
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(defmacro elib-node-set-data (node newdata)
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"Set the data of NODE to NEWDATA."
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(` (aset (, node) 2 (, newdata))))
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(defmacro elib-node-branch (node branch)
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"Get value of a branch of a node.
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NODE is the node, and BRANCH is the branch.
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0 for left pointer, 1 for right pointer and 2 for the data."
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(` (aref (, node) (, branch))))
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(defmacro elib-node-set-branch (node branch newval)
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"Set value of a branch of a node.
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NODE is the node, and BRANCH is the branch.
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0 for left pointer, 1 for the right pointer and 2 for the data.
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NEWVAL is new value of the branch."
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(` (aset (, node) (, branch) (, newval))))
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