1/*	$NetBSD: tfind.c,v 1.6 2011/05/18 19:36:36 dsl Exp $	*/
2
3/*
4 * Tree search generalized from Knuth (6.2.2) Algorithm T just like
5 * the AT&T man page says.
6 *
7 * The node_t structure is for internal use only, lint doesn't grok it.
8 *
9 * Written by reading the System V Interface Definition, not the code.
10 *
11 * Totally public domain.
12 */
13
14#include <sys/cdefs.h>
15#if defined(LIBC_SCCS) && !defined(lint)
16__RCSID("$NetBSD: tfind.c,v 1.6 2011/05/18 19:36:36 dsl Exp $");
17#endif /* LIBC_SCCS and not lint */
18
19#include <assert.h>
20#define _SEARCH_PRIVATE
21#include <stdlib.h>
22#include <search.h>
23
24/* find a node by key "vkey" in tree "vrootp", or return 0 */
25void *
26tfind(const void *vkey, void * const *vrootp,
27    int (*compar)(const void *, const void *))
28{
29	node_t * const *rootp = (node_t * const*)vrootp;
30
31	_DIAGASSERT(vkey != NULL);
32	_DIAGASSERT(compar != NULL);
33
34	if (rootp == NULL)
35		return NULL;
36
37	while (*rootp != NULL) {		/* T1: */
38		int r;
39
40		if ((r = (*compar)(vkey, (*rootp)->key)) == 0)	/* T2: */
41			return *rootp;		/* key found */
42		rootp = (r < 0) ?
43		    &(*rootp)->llink :		/* T3: follow left branch */
44		    &(*rootp)->rlink;		/* T4: follow right branch */
45	}
46	return NULL;
47}
48