lib/libc/stdlib/twalk.c

   1 /*
   2  * Tree search generalized from Knuth (6.2.2) Algorithm T just like
   3  * the AT&T man page says.
   4  *
   5  * The node_t structure is for internal use only, lint doesn't grok it.
   6  *
   7  * Written by reading the System V Interface Definition, not the code.
   8  *
   9  * Totally public domain.
  10  *
  11  * $NetBSD: twalk.c,v 1.1 1999/02/22 10:33:16 christos Exp $
  12  * $FreeBSD: src/lib/libc/stdlib/twalk.c,v 1.5 2003/01/05 02:43:18 tjr Exp $
  13  * $DragonFly: src/lib/libc/stdlib/twalk.c,v 1.5 2005/11/24 17:18:30 swildner Exp $
  14  */
  15
  16 #define _SEARCH_PRIVATE
  17 #include <search.h>
  18 #include <stdlib.h>
  19
  20 static void trecurse(const node_t *,
  21                      void (*action)(const void *, VISIT, int), int level);
  22
  23 /*
  24  * Walk the nodes of a tree
  25  *
  26  * Parameters:
  27  *      root:   Root of the tree to be walked
  28  */
  29 static void
  30 trecurse(const node_t *root, void (*action)(const void *, VISIT, int),
  31          int level)
  32 {
  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 /*
  48  * Walk the nodes of a tree
  49  *
  50  * Parameters:
  51  *      vroot:  Root of the tree to be walked
  52  */
  53 void
  54 twalk(const void *vroot,
  55       void (*action)(const void *, VISIT, int))
  56 {
  57         if (vroot != NULL && action != NULL)
  58                 trecurse(vroot, action, 0);
  59 }