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/*      $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.

 *

 * 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.

 */

#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

#include <assert.h>

#define _SEARCH_PRIVATE

#include <stdlib.h>

#include <search.h>

/* find a node, or return 0 */

void *

_DEFUN(tfind, (vkey, vrootp, compar),

        const void *vkey _AND           /* key to be found */

        void **vrootp _AND              /* address of the tree root */

        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;

}