/*      $NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $  */

/*
 * Tree search generalized from Knuth (6.2.2) Algorithm T just like
 * the AT&T man page says.
 *
 * Written by reading the System V Interface Definition, not the code.
 *
 * Totally public domain.
 */

#include <sys/cdefs.h>
#if 0
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $");
#endif /* LIBC_SCCS and not lint */
#endif
#define _SEARCH_PRIVATE
#include <stdlib.h>
#include <search.h>

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

        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;
}