lib/libc/stdlib/twalk.c

   1 /*      $NetBSD: twalk.c,v 1.2 1999/09/16 11:45:37 lukem 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 1.2 1999/09/16 11:45:37 lukem 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 static void trecurse __P((const node_t *,
  25     void  (*action)(const void *, VISIT, int), int level));
  26
  27 /* Walk the nodes of a tree */
  28 static void
  29 trecurse(root, action, level)
  30         const node_t *root;     /* Root of the tree to be walked */
  31         void (*action) __P((const void *, VISIT, int));
  32         int level;
  33 {
  34         _DIAGASSERT(root != NULL);
  35         _DIAGASSERT(action != NULL);
  36
  37         if (root->llink == NULL && root->rlink == NULL)
  38                 (*action)(root, leaf, level);
  39         else {
  40                 (*action)(root, preorder, level);
  41                 if (root->llink != NULL)
  42                         trecurse(root->llink, action, level + 1);
  43                 (*action)(root, postorder, level);
  44                 if (root->rlink != NULL)
  45                         trecurse(root->rlink, action, level + 1);
  46                 (*action)(root, endorder, level);
  47         }
  48 }
  49
  50 /* Walk the nodes of a tree */
  51 void
  52 twalk(vroot, action)
  53         const void *vroot;      /* Root of the tree to be walked */
  54         void (*action) __P((const void *, VISIT, int));
  55 {
  56         if (vroot != NULL && action != NULL)
  57                 trecurse(vroot, action, 0);
  58 }