1/*	$NetBSD: tfind.c,v 1.3.18.2 2005/03/23 11:12:21 tron 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 <assert.h>
15#define _SEARCH_PRIVATE
16#include <stdlib.h>
17#include <search.h>
18
19
20/* find a node, or return 0 */
21void *
22tfind (const void *vkey, void * const *vrootp,
23       int (*compar) (const void *, const void *))
24{
25  node_t * const *rootp = (node_t * const*)vrootp;
26
27  if (rootp == NULL)
28    return NULL;
29
30  while (*rootp != NULL)
31    {
32      /* T1: */
33      int r;
34
35      if ((r = (*compar)(vkey, (*rootp)->key)) == 0)	/* T2: */
36	return *rootp;		/* key found */
37      rootp = (r < 0) ?
38	  &(*rootp)->llink :		/* T3: follow left branch */
39	  &(*rootp)->rlink;		/* T4: follow right branch */
40    }
41  return NULL;
42}