/*
 * |-----------------------------------------------------------|
 * | Copyright (c) 1991, 1990 MIPS Computer Systems, Inc.      |
 * | All Rights Reserved                                       |
 * |-----------------------------------------------------------|
 * |          Restricted Rights Legend                         |
 * | Use, duplication, or disclosure by the Government is      |
 * | subject to restrictions as set forth in                   |
 * | subparagraph (c)(1)(ii) of the Rights in Technical        |
 * | Data and Computer Software Clause of DFARS 252.227-7013.  |
 * |         MIPS Computer Systems, Inc.                       |
 * |         950 DeGuigne Avenue                               |
 * |         Sunnyvale, California 94088-3650, USA             |
 * |-----------------------------------------------------------|
 */
#ident	"$Header: tfind.c,v 1.8.2.1 92/06/24 14:00:51 marker Exp $"

/*	Copyright (c) 1984 AT&T	*/
/*	  All Rights Reserved  	*/

/*	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T	*/
/*	The copyright notice above does not evidence any   	*/
/*	actual or intended publication of such source code.	*/

/*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>
typedef char *POINTER;
typedef struct node { POINTER key; struct node *llink, *rlink; } NODE;

#define	NULL	0


/*	tfind - find a node, or return 0	*/
NODE *
tfind(key, rootp, compar)
POINTER	key;			/* Key to be located */
register NODE	**rootp;	/* Address of the root of the tree */
int	(*compar)();		/* Comparison function */
{
	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 */
	}
	return (NODE *)(NULL);
}
