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tfind.c revision 1.1 
      1 /*	$NetBSD: tfind.c,v 1.1 1999/02/22 10:33:15 christos Exp $	*/
      2 
      3 /*
      4  * Tree search generalized from Knuth (6.2.2) Algorithm T just like
      5  * the AT&T man page says.
      6  *
      7  * The node_t structure is for internal use only, lint doesn't grok it.
      8  *
      9  * Written by reading the System V Interface Definition, not the code.
     10  *
     11  * Totally public domain.
     12  */
     13 
     14 #include <sys/cdefs.h>
     15 #if defined(LIBC_SCCS) && !defined(lint)
     16 __RCSID("$NetBSD: tfind.c,v 1.1 1999/02/22 10:33:15 christos Exp $");
     17 #endif /* LIBC_SCCS and not lint */
     18 
     19 #define _SEARCH_PRIVATE
     20 #include <stdlib.h>
     21 #include <search.h>
     22 
     23 /* find a node, or return 0 */
     24 void *
     25 tfind(vkey, vrootp, compar)
     26 	const void *vkey;		/* key to be found */
     27 	void **vrootp;			/* address of the tree root */
     28 	int (*compar) __P((const void *, const void *));
     29 {
     30 	node_t **rootp = (node_t **)vrootp;
     31 
     32 	if (rootp == NULL)
     33 		return NULL;
     34 
     35 	while (*rootp != NULL) {		/* T1: */
     36 		int r;
     37 
     38 		if ((r = (*compar)(vkey, (*rootp)->key)) == 0)	/* T2: */
     39 			return *rootp;		/* key found */
     40 		rootp = (r < 0) ?
     41 		    &(*rootp)->llink :		/* T3: follow left branch */
     42 		    &(*rootp)->rlink;		/* T4: follow right branch */
     43 	}
     44 	return NULL;
     45 }
     46