2005-09-21 19:27:14 +08:00
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/* avl.c - routines to implement an avl tree */
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/* $OpenLDAP$ */
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/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
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*
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2006-01-04 07:11:52 +08:00
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* Copyright 2005-2006 The OpenLDAP Foundation.
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2005-09-21 19:27:14 +08:00
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* Portions Copyright (c) 2005 by Howard Chu, Symas Corp.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted only as authorized by the OpenLDAP
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* Public License.
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*
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* A copy of this license is available in the file LICENSE in the
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* top-level directory of the distribution or, alternatively, at
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* <http://www.OpenLDAP.org/license.html>.
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*/
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/* ACKNOWLEDGEMENTS:
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* This work was initially developed by Howard Chu for inclusion
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* in OpenLDAP software.
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*/
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#include "portable.h"
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#include <stdio.h>
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#include <ac/stdlib.h>
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#ifdef CSRIMALLOC
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#define ber_memalloc malloc
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#define ber_memrealloc realloc
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#define ber_memfree free
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#else
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#include "lber.h"
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#endif
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#define AVL_INTERNAL
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#include "avl.h"
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static const int avl_bfs[] = {LH, RH};
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/*
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* Threaded AVL trees - for fast in-order traversal of nodes.
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*/
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/*
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* tavl_insert -- insert a node containing data data into the avl tree
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* with root root. fcmp is a function to call to compare the data portion
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* of two nodes. it should take two arguments and return <, >, or == 0,
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* depending on whether its first argument is <, >, or == its second
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* argument (like strcmp, e.g.). fdup is a function to call when a duplicate
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* node is inserted. it should return 0, or -1 and its return value
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* will be the return value from avl_insert in the case of a duplicate node.
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* the function will be called with the original node's data as its first
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* argument and with the incoming duplicate node's data as its second
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* argument. this could be used, for example, to keep a count with each
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* node.
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*
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* NOTE: this routine may malloc memory
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*/
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int
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tavl_insert( Avlnode ** root, void *data, AVL_CMP fcmp, AVL_DUP fdup )
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{
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Avlnode *t, *p, *s, *q, *r;
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int a, cmp, ncmp;
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if ( *root == NULL ) {
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if (( r = (Avlnode *) ber_memalloc( sizeof( Avlnode ))) == NULL ) {
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return( -1 );
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}
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r->avl_link[0] = r->avl_link[1] = NULL;
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r->avl_data = data;
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r->avl_bf = EH;
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r->avl_bits[0] = r->avl_bits[1] = AVL_THREAD;
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*root = r;
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return( 0 );
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}
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t = NULL;
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s = p = *root;
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/* find insertion point */
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while (1) {
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cmp = fcmp( data, p->avl_data );
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if ( cmp == 0 )
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return (*fdup)( p->avl_data, data );
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cmp = (cmp > 0);
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q = avl_child( p, cmp );
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if (q == NULL) {
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/* insert */
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if (( q = (Avlnode *) ber_memalloc( sizeof( Avlnode ))) == NULL ) {
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return( -1 );
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}
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q->avl_link[cmp] = p->avl_link[cmp];
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q->avl_link[!cmp] = p;
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q->avl_data = data;
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q->avl_bf = EH;
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q->avl_bits[0] = q->avl_bits[1] = AVL_THREAD;
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p->avl_link[cmp] = q;
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p->avl_bits[cmp] = AVL_CHILD;
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break;
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} else if ( q->avl_bf ) {
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t = p;
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s = q;
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}
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p = q;
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}
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/* adjust balance factors */
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cmp = fcmp( data, s->avl_data ) > 0;
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r = p = s->avl_link[cmp];
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a = avl_bfs[cmp];
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while ( p != q ) {
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cmp = fcmp( data, p->avl_data ) > 0;
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p->avl_bf = avl_bfs[cmp];
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p = p->avl_link[cmp];
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}
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/* checks and balances */
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if ( s->avl_bf == EH ) {
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s->avl_bf = a;
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return 0;
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} else if ( s->avl_bf == -a ) {
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s->avl_bf = EH;
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return 0;
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} else if ( s->avl_bf == a ) {
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cmp = (a > 0);
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ncmp = !cmp;
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if ( r->avl_bf == a ) {
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/* single rotation */
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p = r;
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if ( r->avl_bits[ncmp] == AVL_THREAD ) {
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r->avl_bits[ncmp] = AVL_CHILD;
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s->avl_bits[cmp] = AVL_THREAD;
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} else {
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s->avl_link[cmp] = r->avl_link[ncmp];
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r->avl_link[ncmp] = s;
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}
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s->avl_bf = 0;
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r->avl_bf = 0;
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} else if ( r->avl_bf == -a ) {
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/* double rotation */
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p = r->avl_link[ncmp];
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if ( p->avl_bits[cmp] == AVL_THREAD ) {
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p->avl_bits[cmp] = AVL_CHILD;
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r->avl_bits[ncmp] = AVL_THREAD;
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} else {
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r->avl_link[ncmp] = p->avl_link[cmp];
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p->avl_link[cmp] = r;
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}
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if ( p->avl_bits[ncmp] == AVL_THREAD ) {
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p->avl_bits[ncmp] = AVL_CHILD;
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s->avl_link[cmp] = p;
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s->avl_bits[cmp] = AVL_THREAD;
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} else {
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s->avl_link[cmp] = p->avl_link[ncmp];
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p->avl_link[ncmp] = s;
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}
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if ( p->avl_bf == a ) {
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s->avl_bf = -a;
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r->avl_bf = 0;
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} else if ( p->avl_bf == -a ) {
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s->avl_bf = 0;
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r->avl_bf = a;
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} else {
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s->avl_bf = 0;
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r->avl_bf = 0;
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}
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p->avl_bf = 0;
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}
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/* Update parent */
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if ( t == NULL )
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*root = p;
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else if ( s == t->avl_right )
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t->avl_right = p;
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else
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t->avl_left = p;
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}
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return 0;
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}
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void*
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tavl_delete( Avlnode **root, void* data, AVL_CMP fcmp )
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{
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2005-09-26 12:36:19 +08:00
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Avlnode *p, *q, *r, *top;
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2005-11-07 07:27:09 +08:00
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int side, side_bf, shorter, nside = -1;
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2005-09-21 19:27:14 +08:00
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/* parent stack */
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Avlnode *pptr[sizeof(void *)*8];
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unsigned char pdir[sizeof(void *)*8];
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int depth = 0;
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if ( *root == NULL )
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return NULL;
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p = *root;
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while (1) {
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2005-09-21 22:45:35 +08:00
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side = fcmp( data, p->avl_data );
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if ( !side )
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2005-09-21 19:27:14 +08:00
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break;
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2005-09-21 22:45:35 +08:00
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side = ( side > 0 );
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pdir[depth] = side;
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2005-09-21 19:27:14 +08:00
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pptr[depth++] = p;
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2005-09-21 22:45:35 +08:00
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if ( p->avl_bits[side] == AVL_THREAD )
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2005-09-21 19:27:14 +08:00
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return NULL;
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2005-09-21 22:45:35 +08:00
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p = p->avl_link[side];
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2005-09-21 19:27:14 +08:00
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}
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2005-09-21 22:45:35 +08:00
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data = p->avl_data;
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2005-09-21 19:27:14 +08:00
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/* If this node has two children, swap so we are deleting a node with
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* at most one child.
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*/
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if ( p->avl_bits[0] == AVL_CHILD && p->avl_bits[1] == AVL_CHILD &&
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p->avl_link[0] && p->avl_link[1] ) {
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/* find the immediate predecessor <q> */
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q = p->avl_link[0];
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2005-09-22 03:18:40 +08:00
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side = depth;
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pdir[depth++] = 0;
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2005-09-21 19:27:14 +08:00
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while (q->avl_bits[1] == AVL_CHILD && q->avl_link[1]) {
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pdir[depth] = 1;
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pptr[depth++] = q;
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q = q->avl_link[1];
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}
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2005-09-22 03:18:40 +08:00
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/* swap links */
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r = p->avl_link[0];
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p->avl_link[0] = q->avl_link[0];
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q->avl_link[0] = r;
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q->avl_link[1] = p->avl_link[1];
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p->avl_link[1] = q;
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p->avl_bits[0] = q->avl_bits[0];
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p->avl_bits[1] = q->avl_bits[1];
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q->avl_bits[0] = q->avl_bits[1] = AVL_CHILD;
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2005-09-22 09:16:28 +08:00
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q->avl_bf = p->avl_bf;
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2005-09-22 03:18:40 +08:00
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/* fix stack positions: old parent of p points to q */
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pptr[side] = q;
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if ( side ) {
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2005-09-26 16:57:19 +08:00
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r = pptr[side-1];
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r->avl_link[pdir[side-1]] = q;
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2005-09-22 03:18:40 +08:00
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} else {
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*root = q;
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}
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/* new parent of p points to p */
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2005-09-26 16:57:19 +08:00
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if ( depth-side > 1 ) {
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2005-09-26 16:15:37 +08:00
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r = pptr[depth-1];
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2005-09-22 03:18:40 +08:00
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r->avl_link[1] = p;
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} else {
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q->avl_link[0] = p;
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}
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/* fix right subtree: successor of p points to q */
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r = q->avl_link[1];
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while ( r->avl_bits[0] == AVL_CHILD && r->avl_link[0] )
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r = r->avl_link[0];
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r->avl_link[0] = q;
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2005-09-21 19:27:14 +08:00
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}
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/* now <p> has at most one child, get it */
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if ( p->avl_link[0] && p->avl_bits[0] == AVL_CHILD ) {
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q = p->avl_link[0];
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2005-09-21 22:45:35 +08:00
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/* Preserve thread continuity */
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r = p->avl_link[1];
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nside = 1;
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2005-09-21 19:27:14 +08:00
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} else if ( p->avl_link[1] && p->avl_bits[1] == AVL_CHILD ) {
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q = p->avl_link[1];
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2005-09-21 22:45:35 +08:00
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r = p->avl_link[0];
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nside = 0;
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2005-09-21 19:27:14 +08:00
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} else {
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q = NULL;
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2005-09-21 23:19:36 +08:00
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if ( depth > 0 )
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r = p->avl_link[pdir[depth-1]];
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else
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r = NULL;
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2005-09-21 19:27:14 +08:00
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}
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ber_memfree( p );
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2006-05-25 13:03:56 +08:00
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/* Update child thread */
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if ( q ) {
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for ( ; q->avl_bits[nside] == AVL_CHILD && q->avl_link[nside];
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q = q->avl_link[nside] ) ;
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q->avl_link[nside] = r;
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}
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2005-09-21 19:27:14 +08:00
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if ( !depth ) {
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*root = q;
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return data;
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}
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/* set the child into p's parent */
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depth--;
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p = pptr[depth];
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2005-09-21 23:19:36 +08:00
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side = pdir[depth];
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2005-09-21 19:27:14 +08:00
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p->avl_link[side] = q;
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2006-05-25 13:03:56 +08:00
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if ( !q ) {
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2005-09-21 22:45:35 +08:00
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p->avl_bits[side] = AVL_THREAD;
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2005-09-21 23:19:36 +08:00
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p->avl_link[side] = r;
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2005-09-21 19:27:14 +08:00
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}
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2005-09-21 22:45:35 +08:00
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top = NULL;
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2005-09-21 19:27:14 +08:00
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shorter = 1;
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while ( shorter ) {
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2005-09-21 23:19:36 +08:00
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p = pptr[depth];
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side = pdir[depth];
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nside = !side;
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side_bf = avl_bfs[side];
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2005-09-21 19:27:14 +08:00
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/* case 1: height unchanged */
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if ( p->avl_bf == EH ) {
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/* Tree is now heavier on opposite side */
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2005-09-21 22:45:35 +08:00
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p->avl_bf = avl_bfs[nside];
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2005-09-21 19:27:14 +08:00
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shorter = 0;
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} else if ( p->avl_bf == side_bf ) {
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/* case 2: taller subtree shortened, height reduced */
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p->avl_bf = EH;
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} else {
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/* case 3: shorter subtree shortened */
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if ( depth )
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top = pptr[depth-1]; /* p->parent; */
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else
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top = NULL;
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/* set <q> to the taller of the two subtrees of <p> */
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2005-09-21 22:45:35 +08:00
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|
|
q = p->avl_link[nside];
|
2005-09-21 19:27:14 +08:00
|
|
|
if ( q->avl_bf == EH ) {
|
|
|
|
/* case 3a: height unchanged, single rotate */
|
|
|
|
if ( q->avl_bits[side] == AVL_THREAD ) {
|
|
|
|
q->avl_bits[side] = AVL_CHILD;
|
2005-09-21 22:45:35 +08:00
|
|
|
p->avl_bits[nside] = AVL_THREAD;
|
2005-09-21 19:27:14 +08:00
|
|
|
} else {
|
2005-09-21 22:45:35 +08:00
|
|
|
p->avl_link[nside] = q->avl_link[side];
|
2005-09-21 19:27:14 +08:00
|
|
|
q->avl_link[side] = p;
|
|
|
|
}
|
|
|
|
shorter = 0;
|
|
|
|
q->avl_bf = side_bf;
|
|
|
|
p->avl_bf = (- side_bf);
|
|
|
|
|
|
|
|
} else if ( q->avl_bf == p->avl_bf ) {
|
|
|
|
/* case 3b: height reduced, single rotate */
|
|
|
|
if ( q->avl_bits[side] == AVL_THREAD ) {
|
|
|
|
q->avl_bits[side] = AVL_CHILD;
|
2005-09-21 22:45:35 +08:00
|
|
|
p->avl_bits[nside] = AVL_THREAD;
|
2005-09-21 19:27:14 +08:00
|
|
|
} else {
|
2005-09-21 22:45:35 +08:00
|
|
|
p->avl_link[nside] = q->avl_link[side];
|
2005-09-21 19:27:14 +08:00
|
|
|
q->avl_link[side] = p;
|
|
|
|
}
|
|
|
|
shorter = 1;
|
|
|
|
q->avl_bf = EH;
|
|
|
|
p->avl_bf = EH;
|
|
|
|
|
|
|
|
} else {
|
|
|
|
/* case 3c: height reduced, balance factors opposite */
|
|
|
|
r = q->avl_link[side];
|
2005-09-21 22:45:35 +08:00
|
|
|
if ( r->avl_bits[nside] == AVL_THREAD ) {
|
|
|
|
r->avl_bits[nside] = AVL_CHILD;
|
2005-09-21 19:27:14 +08:00
|
|
|
q->avl_bits[side] = AVL_THREAD;
|
|
|
|
} else {
|
2005-09-21 22:45:35 +08:00
|
|
|
q->avl_link[side] = r->avl_link[nside];
|
|
|
|
r->avl_link[nside] = q;
|
2005-09-21 19:27:14 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
if ( r->avl_bits[side] == AVL_THREAD ) {
|
|
|
|
r->avl_bits[side] = AVL_CHILD;
|
2005-09-21 22:45:35 +08:00
|
|
|
p->avl_bits[nside] = AVL_THREAD;
|
|
|
|
p->avl_link[nside] = r;
|
2005-09-21 19:27:14 +08:00
|
|
|
} else {
|
2005-09-21 22:45:35 +08:00
|
|
|
p->avl_link[nside] = r->avl_link[side];
|
2005-09-21 19:27:14 +08:00
|
|
|
r->avl_link[side] = p;
|
|
|
|
}
|
|
|
|
|
|
|
|
if ( r->avl_bf == side_bf ) {
|
|
|
|
q->avl_bf = (- side_bf);
|
|
|
|
p->avl_bf = EH;
|
|
|
|
} else if ( r->avl_bf == (- side_bf)) {
|
|
|
|
q->avl_bf = EH;
|
|
|
|
p->avl_bf = side_bf;
|
|
|
|
} else {
|
|
|
|
q->avl_bf = EH;
|
|
|
|
p->avl_bf = EH;
|
|
|
|
}
|
|
|
|
r->avl_bf = EH;
|
|
|
|
q = r;
|
|
|
|
}
|
|
|
|
/* a rotation has caused <q> (or <r> in case 3c) to become
|
|
|
|
* the root. let <p>'s former parent know this.
|
|
|
|
*/
|
|
|
|
if ( top == NULL ) {
|
|
|
|
*root = q;
|
|
|
|
} else if (top->avl_link[0] == p) {
|
|
|
|
top->avl_link[0] = q;
|
|
|
|
} else {
|
|
|
|
top->avl_link[1] = q;
|
|
|
|
}
|
|
|
|
/* end case 3 */
|
|
|
|
p = q;
|
|
|
|
}
|
|
|
|
if ( !depth )
|
|
|
|
break;
|
|
|
|
depth--;
|
|
|
|
} /* end while(shorter) */
|
|
|
|
|
|
|
|
return data;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* tavl_free -- traverse avltree root, freeing the memory it is using.
|
|
|
|
* the dfree() is called to free the data portion of each node. The
|
|
|
|
* number of items actually freed is returned.
|
|
|
|
*/
|
|
|
|
|
|
|
|
int
|
|
|
|
tavl_free( Avlnode *root, AVL_FREE dfree )
|
|
|
|
{
|
|
|
|
int nleft, nright;
|
|
|
|
|
|
|
|
if ( root == 0 )
|
|
|
|
return( 0 );
|
|
|
|
|
|
|
|
nleft = tavl_free( avl_lchild( root ), dfree );
|
|
|
|
|
|
|
|
nright = tavl_free( avl_rchild( root ), dfree );
|
|
|
|
|
|
|
|
if ( dfree )
|
|
|
|
(*dfree)( root->avl_data );
|
|
|
|
ber_memfree( root );
|
|
|
|
|
|
|
|
return( nleft + nright + 1 );
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* tavl_find -- search avltree root for a node with data data. the function
|
|
|
|
* cmp is used to compare things. it is called with data as its first arg
|
|
|
|
* and the current node data as its second. it should return 0 if they match,
|
|
|
|
* < 0 if arg1 is less than arg2 and > 0 if arg1 is greater than arg2.
|
|
|
|
*/
|
|
|
|
|
2006-05-19 23:24:16 +08:00
|
|
|
/*
|
|
|
|
* tavl_find2 - returns Avlnode instead of data pointer.
|
|
|
|
* tavl_find3 - as above, but returns Avlnode even if no match is found.
|
|
|
|
* also return the last comparison result in ret.
|
|
|
|
*/
|
|
|
|
Avlnode *
|
|
|
|
tavl_find3( Avlnode *root, const void *data, AVL_CMP fcmp, int *ret )
|
|
|
|
{
|
|
|
|
int cmp, dir;
|
|
|
|
Avlnode *prev;
|
|
|
|
|
|
|
|
while ( root != 0 && (cmp = (*fcmp)( data, root->avl_data )) != 0 ) {
|
|
|
|
prev = root;
|
|
|
|
dir = cmp > 0;
|
|
|
|
root = avl_child( root, dir );
|
|
|
|
}
|
|
|
|
*ret = cmp;
|
|
|
|
return root ? root : prev;
|
|
|
|
}
|
|
|
|
|
2005-09-21 19:27:14 +08:00
|
|
|
Avlnode *
|
|
|
|
tavl_find2( Avlnode *root, const void *data, AVL_CMP fcmp )
|
|
|
|
{
|
|
|
|
int cmp;
|
|
|
|
|
|
|
|
while ( root != 0 && (cmp = (*fcmp)( data, root->avl_data )) != 0 ) {
|
2005-09-21 22:45:35 +08:00
|
|
|
cmp = cmp > 0;
|
|
|
|
root = avl_child( root, cmp );
|
2005-09-21 19:27:14 +08:00
|
|
|
}
|
|
|
|
return root;
|
|
|
|
}
|
|
|
|
|
|
|
|
void*
|
|
|
|
tavl_find( Avlnode *root, const void* data, AVL_CMP fcmp )
|
|
|
|
{
|
|
|
|
int cmp;
|
|
|
|
|
|
|
|
while ( root != 0 && (cmp = (*fcmp)( data, root->avl_data )) != 0 ) {
|
2005-09-21 22:45:35 +08:00
|
|
|
cmp = cmp > 0;
|
|
|
|
root = avl_child( root, cmp );
|
2005-09-21 19:27:14 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
return( root ? root->avl_data : 0 );
|
|
|
|
}
|
2005-09-21 22:45:35 +08:00
|
|
|
|
|
|
|
/* Return the leftmost or rightmost node in the tree */
|
|
|
|
Avlnode *
|
|
|
|
tavl_end( Avlnode *root, int dir )
|
|
|
|
{
|
|
|
|
if ( root ) {
|
2005-09-23 14:27:16 +08:00
|
|
|
while ( root->avl_bits[dir] == AVL_CHILD )
|
2005-09-21 22:45:35 +08:00
|
|
|
root = root->avl_link[dir];
|
|
|
|
}
|
|
|
|
return root;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Return the next node in the given direction */
|
|
|
|
Avlnode *
|
|
|
|
tavl_next( Avlnode *root, int dir )
|
|
|
|
{
|
|
|
|
if ( root ) {
|
|
|
|
int c = root->avl_bits[dir];
|
|
|
|
|
|
|
|
root = root->avl_link[dir];
|
|
|
|
if ( c == AVL_CHILD ) {
|
|
|
|
dir ^= 1;
|
2005-09-23 14:27:16 +08:00
|
|
|
while ( root->avl_bits[dir] == AVL_CHILD )
|
2005-09-21 22:45:35 +08:00
|
|
|
root = root->avl_link[dir];
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return root;
|
|
|
|
}
|