freebsd-dev/lib/libc/stdlib/twalk.c
Alfred Perlstein 64566a3e2a bring in binary search tree code.
Obtained from: NetBSD
2000-07-01 06:55:11 +00:00

58 lines
1.5 KiB
C

/* $NetBSD: twalk.c,v 1.1 1999/02/22 10:33:16 christos Exp $ */
/* $FreeBSD$ */
/*
* 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.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: twalk.c,v 1.1 1999/02/22 10:33:16 christos Exp $");
#endif /* LIBC_SCCS and not lint */
#include <assert.h>
#define _SEARCH_PRIVATE
#include <search.h>
#include <stdlib.h>
static void trecurse __P((const node_t *,
void (*action)(const void *, VISIT, int), int level));
/* Walk the nodes of a tree */
static void
trecurse(root, action, level)
const node_t *root; /* Root of the tree to be walked */
void (*action) __P((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 */
void
twalk(vroot, action)
const void *vroot; /* Root of the tree to be walked */
void (*action) __P((const void *, VISIT, int));
{
if (vroot != NULL && action != NULL)
trecurse(vroot, action, 0);
}