1 /* $NetBSD: tsearch.c,v 1.3 1999/09/16 11:45:37 lukem Exp $ */
2 /* $FreeBSD: src/lib/libc/stdlib/tsearch.c,v 1.1.2.1 2000/08/17 07:38:39 jhb Exp $ */
5 * Tree search generalized from Knuth (6.2.2) Algorithm T just like
6 * the AT&T man page says.
8 * The node_t structure is for internal use only, lint doesn't grok it.
10 * Written by reading the System V Interface Definition, not the code.
12 * Totally public domain.
15 #include <sys/cdefs.h>
16 #if defined(LIBC_SCCS) && !defined(lint)
17 __RCSID("$NetBSD: tsearch.c,v 1.3 1999/09/16 11:45:37 lukem Exp $");
18 #endif /* LIBC_SCCS and not lint */
21 #define _SEARCH_PRIVATE
25 /* find or insert datum into search tree */
27 tsearch(vkey, vrootp, compar)
28 const void *vkey; /* key to be located */
29 void **vrootp; /* address of tree root */
30 int (*compar) __P((const void *, const void *));
33 node_t **rootp = (node_t **)vrootp;
38 while (*rootp != NULL) { /* Knuth's T1: */
41 if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */
42 return *rootp; /* we found it! */
45 &(*rootp)->llink : /* T3: follow left branch */
46 &(*rootp)->rlink; /* T4: follow right branch */
49 q = malloc(sizeof(node_t)); /* T5: key not found */
50 if (q != 0) { /* make new node */
51 *rootp = q; /* link new node to old */
52 /* LINTED const castaway ok */
53 q->key = (void *)vkey; /* initialize new node */
54 q->llink = q->rlink = NULL;