1*86d7f5d3SJohn Marino /*
2*86d7f5d3SJohn Marino * Tree search generalized from Knuth (6.2.2) Algorithm T just like
3*86d7f5d3SJohn Marino * the AT&T man page says.
4*86d7f5d3SJohn Marino *
5*86d7f5d3SJohn Marino * The node_t structure is for internal use only, lint doesn't grok it.
6*86d7f5d3SJohn Marino *
7*86d7f5d3SJohn Marino * Written by reading the System V Interface Definition, not the code.
8*86d7f5d3SJohn Marino *
9*86d7f5d3SJohn Marino * Totally public domain.
10*86d7f5d3SJohn Marino *
11*86d7f5d3SJohn Marino * $NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $
12*86d7f5d3SJohn Marino * $FreeBSD: src/lib/libc/stdlib/tfind.c,v 1.5 2003/01/05 02:43:18 tjr Exp $
13*86d7f5d3SJohn Marino * $DragonFly: src/lib/libc/stdlib/tsearch.c,v 1.6 2005/11/24 17:18:30 swildner Exp $
14*86d7f5d3SJohn Marino */
15*86d7f5d3SJohn Marino
16*86d7f5d3SJohn Marino #define _SEARCH_PRIVATE
17*86d7f5d3SJohn Marino #include <stdlib.h>
18*86d7f5d3SJohn Marino #include <search.h>
19*86d7f5d3SJohn Marino
20*86d7f5d3SJohn Marino /*
21*86d7f5d3SJohn Marino * find a node, or return 0
22*86d7f5d3SJohn Marino *
23*86d7f5d3SJohn Marino * Parameters:
24*86d7f5d3SJohn Marino * vkey: key to be found
25*86d7f5d3SJohn Marino * vrootp: address of the tree root
26*86d7f5d3SJohn Marino */
27*86d7f5d3SJohn Marino void *
tfind(const void * vkey,void * const * vrootp,int (* compar)(const void *,const void *))28*86d7f5d3SJohn Marino tfind(const void *vkey, void * const *vrootp,
29*86d7f5d3SJohn Marino int (*compar)(const void *, const void *))
30*86d7f5d3SJohn Marino {
31*86d7f5d3SJohn Marino node_t **rootp = (node_t **)vrootp;
32*86d7f5d3SJohn Marino
33*86d7f5d3SJohn Marino if (rootp == NULL)
34*86d7f5d3SJohn Marino return NULL;
35*86d7f5d3SJohn Marino
36*86d7f5d3SJohn Marino while (*rootp != NULL) { /* T1: */
37*86d7f5d3SJohn Marino int r;
38*86d7f5d3SJohn Marino
39*86d7f5d3SJohn Marino if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */
40*86d7f5d3SJohn Marino return *rootp; /* key found */
41*86d7f5d3SJohn Marino rootp = (r < 0) ?
42*86d7f5d3SJohn Marino &(*rootp)->llink : /* T3: follow left branch */
43*86d7f5d3SJohn Marino &(*rootp)->rlink; /* T4: follow right branch */
44*86d7f5d3SJohn Marino }
45*86d7f5d3SJohn Marino return NULL;
46*86d7f5d3SJohn Marino }
47