1 /* $NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem 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 0
16 #if defined(LIBC_SCCS) && !defined(lint)
17 __RCSID("$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $");
18 #endif /* LIBC_SCCS and not lint */
19 #endif
20 __FBSDID("$FreeBSD$");
21
22 #define _SEARCH_PRIVATE
23 #include <stdlib.h>
24 #include <search.h>
25
26 /*
27 * find a node, or return 0
28 *
29 * vkey - key to be found
30 * vrootp - address of the tree root
31 */
32 void *
tfind(const void * vkey,void * const * vrootp,int (* compar)(const void *,const void *))33 tfind(const void *vkey, void * const *vrootp,
34 int (*compar)(const void *, const void *))
35 {
36 node_t **rootp = (node_t **)vrootp;
37
38 if (rootp == NULL)
39 return NULL;
40
41 while (*rootp != NULL) { /* T1: */
42 int r;
43
44 if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */
45 return *rootp; /* key found */
46 rootp = (r < 0) ?
47 &(*rootp)->llink : /* T3: follow left branch */
48 &(*rootp)->rlink; /* T4: follow right branch */
49 }
50 return NULL;
51 }
52