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 defined(LIBC_SCCS) && !defined(lint)
16 __RCSID("$NetBSD: twalk.c,v 1.4 2012/03/20 16:38:45 matt Exp $");
17 #endif /* LIBC_SCCS and not lint */
18
19 #include <assert.h>
20 #define _SEARCH_PRIVATE
21 #include <search.h>
22 #include <stdlib.h>
23
24 typedef void (*cmp_fn_t)(const void *, VISIT, int);
25
26 /* Walk the nodes of a tree */
27 static void
trecurse(const node_t * root,cmp_fn_t action,int level)28 trecurse(const node_t *root, /* Root of the tree to be walked */
29 cmp_fn_t action, int level)
30 {
31 _DIAGASSERT(root != NULL);
32 _DIAGASSERT(action != NULL);
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 */
48 void
twalk(const void * vroot,cmp_fn_t action)49 twalk(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