twalk.c revision 108694 
1/*	$NetBSD: twalk.c,v 1.1 1999/02/22 10:33:16 christos 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 0
16#if defined(LIBC_SCCS) && !defined(lint)
17__RCSID("$NetBSD: twalk.c,v 1.1 1999/02/22 10:33:16 christos Exp $");
18#endif /* LIBC_SCCS and not lint */
19#endif
20__FBSDID("$FreeBSD: head/lib/libc/stdlib/twalk.c 108694 2003-01-05 02:43:18Z tjr $");
21
22#define _SEARCH_PRIVATE
23#include <search.h>
24#include <stdlib.h>
25
26static void trecurse(const node_t *,
27    void (*action)(const void *, VISIT, int), int level);
28
29/* Walk the nodes of a tree */
30static void
31trecurse(root, action, level)
32	const node_t *root;	/* Root of the tree to be walked */
33	void (*action)(const void *, VISIT, int);
34	int level;
35{
36
37	if (root->llink == NULL && root->rlink == NULL)
38		(*action)(root, leaf, level);
39	else {
40		(*action)(root, preorder, level);
41		if (root->llink != NULL)
42			trecurse(root->llink, action, level + 1);
43		(*action)(root, postorder, level);
44		if (root->rlink != NULL)
45			trecurse(root->rlink, action, level + 1);
46		(*action)(root, endorder, level);
47	}
48}
49
50/* Walk the nodes of a tree */
51void
52twalk(vroot, action)
53	const void *vroot;	/* Root of the tree to be walked */
54	void (*action)(const void *, VISIT, int);
55{
56	if (vroot != NULL && action != NULL)
57		trecurse(vroot, action, 0);
58}
59