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}