/*
 * Tree search generalized from Knuth (6.2.2) Algorithm T just like
 * the AT&T man page says.
 *
 * The node_t structure is for internal use only, lint doesn't grok it.
 *
 * Written by reading the System V Interface Definition, not the code.
 *
 * Totally public domain.
 *
 * $NetBSD: twalk.c,v 1.1 1999/02/22 10:33:16 christos Exp $
 * $FreeBSD: src/lib/libc/stdlib/twalk.c,v 1.5 2003/01/05 02:43:18 tjr Exp $
 * $DragonFly: src/lib/libc/stdlib/twalk.c,v 1.5 2005/11/24 17:18:30 swildner Exp $
 */

#define _SEARCH_PRIVATE
#include <search.h>
#include <stdlib.h>

static void trecurse(const node_t *,
		     void (*action)(const void *, VISIT, int), int level);

/*
 * Walk the nodes of a tree
 *
 * Parameters:
 *	root:	Root of the tree to be walked
 */
static void
trecurse(const node_t *root, void (*action)(const void *, VISIT, int),
	 int level)
{

	if (root->llink == NULL && root->rlink == NULL)
		(*action)(root, leaf, level);
	else {
		(*action)(root, preorder, level);
		if (root->llink != NULL)
			trecurse(root->llink, action, level + 1);
		(*action)(root, postorder, level);
		if (root->rlink != NULL)
			trecurse(root->rlink, action, level + 1);
		(*action)(root, endorder, level);
	}
}

/*
 * Walk the nodes of a tree
 *
 * Parameters:
 *	vroot:	Root of the tree to be walked
 */
void
twalk(const void *vroot,
      void (*action)(const void *, VISIT, int))
{
	if (vroot != NULL && action != NULL)
		trecurse(vroot, action, 0);
}