xref: /illumos-gate/usr/src/lib/libc/port/gen/tfind.c (revision 03831d35)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*	Copyright (c) 1988 AT&T	*/
30 /*	  All Rights Reserved  	*/
31 
32 
33 /*
34  * Tree search algorithm, generalized from Knuth (6.2.2) Algorithm T.
35  *
36  * The NODE * arguments are declared in the lint files as char *,
37  * because the definition of NODE isn't available to the user.
38  */
39 
40 #pragma weak tfind = _tfind
41 
42 #include "synonyms.h"
43 #include <mtlib.h>
44 #include <sys/types.h>
45 #include <search.h>
46 #include <thread.h>
47 #include <synch.h>
48 
49 typedef struct node { void *key; struct node *llink, *rlink; } NODE;
50 
51 
52 /*	tfind - find a node, or return 0	*/
53 /*
54  * ky is Key to be located
55  * rtp is the Address of the root of the tree
56  * compar is the Comparison function
57  */
58 void *
59 tfind(const void *ky, void *const *rtp,
60     int (*compar)(const void *, const void *))
61 {
62 	void *key = (char *)ky;
63 	NODE **rootp = (NODE **)rtp;
64 	if (rootp == NULL)
65 		return (NULL);
66 	while (*rootp != NULL) {			/* T1: */
67 		int r = (*compar)(key, (*rootp)->key);	/* T2: */
68 		if (r == 0)
69 			return ((void *)*rootp);	/* Key found */
70 		rootp = (r < 0) ?
71 		    &(*rootp)->llink :		/* T3: Take left branch */
72 		    &(*rootp)->rlink;		/* T4: Take right branch */
73 	}
74 	return (NULL);
75 }
76