xref: /onnv-gate/usr/src/lib/libc/port/gen/tfind.c (revision 6812:febeba71273d)
10Sstevel@tonic-gate /*
20Sstevel@tonic-gate  * CDDL HEADER START
30Sstevel@tonic-gate  *
40Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*6812Sraf  * Common Development and Distribution License (the "License").
6*6812Sraf  * You may not use this file except in compliance with the License.
70Sstevel@tonic-gate  *
80Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
90Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
100Sstevel@tonic-gate  * See the License for the specific language governing permissions
110Sstevel@tonic-gate  * and limitations under the License.
120Sstevel@tonic-gate  *
130Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
140Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
150Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
160Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
170Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
180Sstevel@tonic-gate  *
190Sstevel@tonic-gate  * CDDL HEADER END
200Sstevel@tonic-gate  */
21*6812Sraf 
220Sstevel@tonic-gate /*
23*6812Sraf  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
240Sstevel@tonic-gate  * Use is subject to license terms.
250Sstevel@tonic-gate  */
260Sstevel@tonic-gate 
270Sstevel@tonic-gate /*	Copyright (c) 1988 AT&T	*/
280Sstevel@tonic-gate /*	  All Rights Reserved  	*/
290Sstevel@tonic-gate 
30*6812Sraf #pragma ident	"%Z%%M%	%I%	%E% SMI"
310Sstevel@tonic-gate 
320Sstevel@tonic-gate /*
330Sstevel@tonic-gate  * Tree search algorithm, generalized from Knuth (6.2.2) Algorithm T.
340Sstevel@tonic-gate  *
350Sstevel@tonic-gate  * The NODE * arguments are declared in the lint files as char *,
360Sstevel@tonic-gate  * because the definition of NODE isn't available to the user.
370Sstevel@tonic-gate  */
380Sstevel@tonic-gate 
39*6812Sraf #pragma weak _tfind = tfind
400Sstevel@tonic-gate 
41*6812Sraf #include "lint.h"
420Sstevel@tonic-gate #include <mtlib.h>
430Sstevel@tonic-gate #include <sys/types.h>
440Sstevel@tonic-gate #include <search.h>
450Sstevel@tonic-gate #include <thread.h>
460Sstevel@tonic-gate #include <synch.h>
470Sstevel@tonic-gate 
480Sstevel@tonic-gate typedef struct node { void *key; struct node *llink, *rlink; } NODE;
490Sstevel@tonic-gate 
500Sstevel@tonic-gate 
510Sstevel@tonic-gate /*	tfind - find a node, or return 0	*/
520Sstevel@tonic-gate /*
530Sstevel@tonic-gate  * ky is Key to be located
540Sstevel@tonic-gate  * rtp is the Address of the root of the tree
550Sstevel@tonic-gate  * compar is the Comparison function
560Sstevel@tonic-gate  */
570Sstevel@tonic-gate void *
tfind(const void * ky,void * const * rtp,int (* compar)(const void *,const void *))580Sstevel@tonic-gate tfind(const void *ky, void *const *rtp,
590Sstevel@tonic-gate     int (*compar)(const void *, const void *))
600Sstevel@tonic-gate {
610Sstevel@tonic-gate 	void *key = (char *)ky;
620Sstevel@tonic-gate 	NODE **rootp = (NODE **)rtp;
630Sstevel@tonic-gate 	if (rootp == NULL)
640Sstevel@tonic-gate 		return (NULL);
650Sstevel@tonic-gate 	while (*rootp != NULL) {			/* T1: */
660Sstevel@tonic-gate 		int r = (*compar)(key, (*rootp)->key);	/* T2: */
670Sstevel@tonic-gate 		if (r == 0)
680Sstevel@tonic-gate 			return ((void *)*rootp);	/* Key found */
690Sstevel@tonic-gate 		rootp = (r < 0) ?
700Sstevel@tonic-gate 		    &(*rootp)->llink :		/* T3: Take left branch */
710Sstevel@tonic-gate 		    &(*rootp)->rlink;		/* T4: Take right branch */
720Sstevel@tonic-gate 	}
730Sstevel@tonic-gate 	return (NULL);
740Sstevel@tonic-gate }
75