/*
 * Tree search generalized from Knuth (6.2.2) Algorithm T just like
 * the AT&T man page says.
 *
 * The node_t structure is for internal use only, lint doesn't grok it.
 *
 * Written by reading the System V Interface Definition, not the code.
 *
 * Totally public domain.
 *
 * $NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $
 * $FreeBSD: src/lib/libc/stdlib/tfind.c,v 1.5 2003/01/05 02:43:18 tjr Exp $
 * $DragonFly: src/lib/libc/stdlib/tsearch.c,v 1.6 2005/11/24 17:18:30 swildner Exp $
 */

#define _SEARCH_PRIVATE
#include <stdlib.h>
#include <search.h>

/*
 * find a node, or return 0
 *
 * Parameters:
 *      vkey:   key to be found
 *      vrootp: address of the tree root
 */
void *
tfind(const void *vkey, void * const *vrootp,
      int (*compar)(const void *, const void *))
{
        node_t **rootp = (node_t **)vrootp;

        if (rootp == NULL)
                return NULL;

        while (*rootp != NULL) {                /* T1: */
                int r;

                if ((r = (*compar)(vkey, (*rootp)->key)) == 0)  /* T2: */
                        return *rootp;          /* key found */
                rootp = (r < 0) ?
                    &(*rootp)->llink :          /* T3: follow left branch */
                    &(*rootp)->rlink;           /* T4: follow right branch */
        }
        return NULL;
}