1 /* $NetBSD: tsearch.c,v 1.7 2012/06/25 22:32:45 abs Exp $ */
4 * Tree search generalized from Knuth (6.2.2) Algorithm T just like
5 * the AT&T man page says.
7 * The node_t structure is for internal use only, lint doesn't grok it.
9 * Written by reading the System V Interface Definition, not the code.
11 * Totally public domain.
14 #include <sys/cdefs.h>
16 #if defined(LIBC_SCCS) && !defined(lint)
17 __RCSID("$NetBSD: tsearch.c,v 1.7 2012/06/25 22:32:45 abs Exp $");
18 #endif /* LIBC_SCCS and not lint */
20 __FBSDID("$FreeBSD$");
22 #define _SEARCH_PRIVATE
26 /* find or insert datum into search tree */
28 tsearch(const void *vkey, void **vrootp,
29 int (*compar)(const void *, const void *))
32 node_t **rootp = (node_t **)vrootp;
37 while (*rootp != NULL) { /* Knuth's T1: */
40 if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */
41 return *rootp; /* we found it! */
44 &(*rootp)->llink : /* T3: follow left branch */
45 &(*rootp)->rlink; /* T4: follow right branch */
48 q = malloc(sizeof(node_t)); /* T5: key not found */
49 if (q != 0) { /* make new node */
50 *rootp = q; /* link new node to old */
51 q->key = __DECONST(void *, vkey);/* initialize new node */
52 q->llink = q->rlink = NULL;