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      1 /*	$NetBSD: twalk.c,v 1.4 2012/03/20 16:38:45 matt 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: twalk.c,v 1.4 2012/03/20 16:38:45 matt Exp $");
     17 #endif /* LIBC_SCCS and not lint */
     18 
     19 #include <assert.h>
     20 #define _SEARCH_PRIVATE
     21 #include <search.h>
     22 #include <stdlib.h>
     23 
     24 typedef void (*cmp_fn_t)(const void *, VISIT, int);
     25 
     26 /* Walk the nodes of a tree */
     27 static void
     28 trecurse(const node_t *root,	/* Root of the tree to be walked */
     29 	cmp_fn_t action, int level)
     30 {
     31 	_DIAGASSERT(root != NULL);
     32 	_DIAGASSERT(action != NULL);
     33 
     34 	if (root->llink == NULL && root->rlink == NULL)
     35 		(*action)(root, leaf, level);
     36 	else {
     37 		(*action)(root, preorder, level);
     38 		if (root->llink != NULL)
     39 			trecurse(root->llink, action, level + 1);
     40 		(*action)(root, postorder, level);
     41 		if (root->rlink != NULL)
     42 			trecurse(root->rlink, action, level + 1);
     43 		(*action)(root, endorder, level);
     44 	}
     45 }
     46 
     47 /* Walk the nodes of a tree */
     48 void
     49 twalk(const void *vroot, cmp_fn_t action) /* Root of the tree to be walked */
     50 {
     51 	if (vroot != NULL && action != NULL)
     52 		trecurse(vroot, action, 0);
     53 }
     54