xref: /titanic_52/usr/src/lib/libbc/libc/gen/common/tfind.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)
1*7c478bd9Sstevel@tonic-gate /*
2*7c478bd9Sstevel@tonic-gate  * CDDL HEADER START
3*7c478bd9Sstevel@tonic-gate  *
4*7c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*7c478bd9Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*7c478bd9Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*7c478bd9Sstevel@tonic-gate  * with the License.
8*7c478bd9Sstevel@tonic-gate  *
9*7c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*7c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*7c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*7c478bd9Sstevel@tonic-gate  * and limitations under the License.
13*7c478bd9Sstevel@tonic-gate  *
14*7c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*7c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*7c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*7c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*7c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*7c478bd9Sstevel@tonic-gate  *
20*7c478bd9Sstevel@tonic-gate  * CDDL HEADER END
21*7c478bd9Sstevel@tonic-gate  */
22*7c478bd9Sstevel@tonic-gate /*      Copyright (c) 1984 AT&T */
23*7c478bd9Sstevel@tonic-gate /*        All Rights Reserved   */
24*7c478bd9Sstevel@tonic-gate 
25*7c478bd9Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 1.2 */
26*7c478bd9Sstevel@tonic-gate 
27*7c478bd9Sstevel@tonic-gate /*LINTLIBRARY*/
28*7c478bd9Sstevel@tonic-gate /*
29*7c478bd9Sstevel@tonic-gate  * Tree search algorithm, generalized from Knuth (6.2.2) Algorithm T.
30*7c478bd9Sstevel@tonic-gate  *
31*7c478bd9Sstevel@tonic-gate  * The NODE * arguments are declared in the lint files as char *,
32*7c478bd9Sstevel@tonic-gate  * because the definition of NODE isn't available to the user.
33*7c478bd9Sstevel@tonic-gate  */
34*7c478bd9Sstevel@tonic-gate 
35*7c478bd9Sstevel@tonic-gate #include <search.h>
36*7c478bd9Sstevel@tonic-gate typedef char *POINTER;
37*7c478bd9Sstevel@tonic-gate typedef struct node { POINTER key; struct node *llink, *rlink; } NODE;
38*7c478bd9Sstevel@tonic-gate 
39*7c478bd9Sstevel@tonic-gate #define	NULL	0
40*7c478bd9Sstevel@tonic-gate 
41*7c478bd9Sstevel@tonic-gate 
42*7c478bd9Sstevel@tonic-gate /*	tfind - find a node, or return 0	*/
43*7c478bd9Sstevel@tonic-gate NODE *
44*7c478bd9Sstevel@tonic-gate tfind(key, rootp, compar)
45*7c478bd9Sstevel@tonic-gate POINTER	key;			/* Key to be located */
46*7c478bd9Sstevel@tonic-gate register NODE	**rootp;	/* Address of the root of the tree */
47*7c478bd9Sstevel@tonic-gate int	(*compar)();		/* Comparison function */
48*7c478bd9Sstevel@tonic-gate {
49*7c478bd9Sstevel@tonic-gate 	if (rootp == NULL)
50*7c478bd9Sstevel@tonic-gate 		return (NULL);
51*7c478bd9Sstevel@tonic-gate 	while (*rootp != NULL) {			/* T1: */
52*7c478bd9Sstevel@tonic-gate 		int r = (*compar)(key, (*rootp)->key);	/* T2: */
53*7c478bd9Sstevel@tonic-gate 		if (r == 0)
54*7c478bd9Sstevel@tonic-gate 			return (*rootp);	/* Key found */
55*7c478bd9Sstevel@tonic-gate 		rootp = (r < 0) ?
56*7c478bd9Sstevel@tonic-gate 		    &(*rootp)->llink :		/* T3: Take left branch */
57*7c478bd9Sstevel@tonic-gate 		    &(*rootp)->rlink;		/* T4: Take right branch */
58*7c478bd9Sstevel@tonic-gate 	}
59*7c478bd9Sstevel@tonic-gate 	return (NODE *)(NULL);
60*7c478bd9Sstevel@tonic-gate }
61