twalk.c revision 302408 
1/*	$NetBSD: twalk.c,v 1.4 2012/03/20 16:38:45 matt 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 1.4 2012/03/20 16:38:45 matt Exp $");
18#endif /* LIBC_SCCS and not lint */
19#endif
20__FBSDID("$FreeBSD: stable/11/lib/libc/stdlib/twalk.c 268644 2014-07-15 03:28:37Z pfg $");
21
22#define _SEARCH_PRIVATE
23#include <search.h>
24#include <stdlib.h>
25
26typedef void (*cmp_fn_t)(const void *, VISIT, int);
27
28/* Walk the nodes of a tree */
29static void
30trecurse(const node_t *root,	/* Root of the tree to be walked */
31	cmp_fn_t action, int level)
32{
33
34	if (root->llink == NULL && root->rlink == NULL)
35		(*action)(root, leaf, level);
36	else {
37		(*action)(root, preorder, level);
38		if (root->llink != NULL)
39			trecurse(root->llink, action, level + 1);
40		(*action)(root, postorder, level);
41		if (root->rlink != NULL)
42			trecurse(root->rlink, action, level + 1);
43		(*action)(root, endorder, level);
44	}
45}
46
47/* Walk the nodes of a tree */
48void
49twalk(const void *vroot, cmp_fn_t action) /* Root of the tree to be walked */
50{
51	if (vroot != NULL && action != NULL)
52		trecurse(vroot, action, 0);
53}
54