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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/* Copyright (c) 1984 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI"
/*LINTLIBRARY*/
/*
* Tree search algorithm, generalized from Knuth (6.2.2) Algorithm T.
*
*
* The NODE * arguments are declared in the lint files as char *,
* because the definition of NODE isn't available to the user.
*/
#include <search.h>
#include <stdio.h>
#include <malloc.h>
typedef char *POINTER;
typedef struct node { POINTER key; struct node *llink, *rlink; } NODE;
/*
* Find or insert key into search tree
*
* Arguments
* key: Key to be located
* rootp: Address of the root of the tree
* compar: Comparison function
*/
NODE *
tsearch(POINTER key, NODE **rootp, int (*compar)(POINTER, POINTER))
{
NODE *q; /* New node if key not found */
if (rootp == NULL)
return (NULL);
while (*rootp != NULL) { /* T1: */
int r = (*compar)(key, (*rootp)->key); /* T2: */
if (r == 0)
return (*rootp); /* Key found */
rootp = (r < 0) ?
&(*rootp)->llink : /* T3: Take left branch */
&(*rootp)->rlink; /* T4: Take right branch */
}
q = (NODE *) malloc(sizeof(NODE)); /* T5: Not found */
if (q != NULL) { /* Allocate new node */
*rootp = q; /* Link new node to old */
q->key = key; /* Initialize new node */
q->llink = q->rlink = NULL;
}
return (q);
}
/*
* Delete node with key key
*
* Arguments
* key: Key to be deleted
* rootp: Address of the root of tree
* compar: Comparison function
*/
NODE *
tdelete(POINTER key, NODE **rootp, int (*compar)(POINTER, POINTER))
{
NODE *p; /* Parent of node to be deleted */
NODE *q; /* Successor node */
NODE *r; /* Right son node */
int ans; /* Result of comparison */
if (rootp == NULL || (p = *rootp) == NULL)
return (NULL);
while ((ans = (*compar)(key, (*rootp)->key)) != 0) {
p = *rootp;
rootp = (ans < 0) ?
&(*rootp)->llink : /* Take left branch */
&(*rootp)->rlink; /* Take right branch */
if (*rootp == NULL)
return (NULL); /* Key not found */
}
r = (*rootp)->rlink; /* D1: */
if ((q = (*rootp)->llink) == NULL) /* Llink NULL? */
q = r;
else if (r != NULL) { /* Rlink NULL? */
if (r->llink == NULL) { /* D2: Find successor */
r->llink = q;
q = r;
} else { /* D3: Find NULL link */
for (q = r->llink; q->llink != NULL; q = r->llink)
r = q;
r->llink = q->rlink;
q->llink = (*rootp)->llink;
q->rlink = (*rootp)->rlink;
}
}
free((POINTER) *rootp); /* D4: Free node */
*rootp = q; /* Link parent to replacement */
return (p);
}
static void _twalk(NODE *, void (*)(NODE *, VISIT, int), int);
/*
* Walk the nodes of a tree
*
* Arguments
* root: Root of the tree to be walked
* action: Function to be called at each node
*/
void
twalk(NODE *root, void (*action)(NODE *, VISIT, int))
{
if (root != NULL && action != NULL)
_twalk(root, action, 0);
}
/*
* Walk the nodes of a tree
*
* Arguments
* root: Root of the tree to be walked
* action: Function to be called at each node
*/
static void
_twalk(NODE *root, void (*action)(NODE *, VISIT, int), int level)
{
if (root->llink == NULL && root->rlink == NULL)
(*action)(root, leaf, level);
else {
(*action)(root, preorder, level);
if (root->llink != NULL)
_twalk(root->llink, action, level + 1);
(*action)(root, postorder, level);
if (root->rlink != NULL)
_twalk(root->rlink, action, level + 1);
(*action)(root, endorder, level);
}
}
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