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 1.1.2.1 2000/08/17 07:38:39 jhb Exp $
  13  * $DragonFly: src/lib/libc/stdlib/twalk.c,v 1.5 2005/11/24 17:18:30 swildner Exp $
  14  */
  15
  16 #include <sys/cdefs.h>
  17
  18 #include <assert.h>
  19 #define _SEARCH_PRIVATE
  20 #include <search.h>
  21 #include <stdlib.h>
  22
  23 static void trecurse (const node_t *,
  24     void  (*action)(const void *, VISIT, int), int level);
  25
  26 /* Walk the nodes of a tree
  27  *
  28  * Parameters:
  29  *      root:   Root of the tree to be walked
  30  */
  31 static void
  32 trecurse(const node_t *root, void (*action)(const void *, VISIT, int),
  33          int level)
  34 {
  35
  36         if (root->llink == NULL && root->rlink == NULL)
  37                 (*action)(root, leaf, level);
  38         else {
  39                 (*action)(root, preorder, level);
  40                 if (root->llink != NULL)
  41                         trecurse(root->llink, action, level + 1);
  42                 (*action)(root, postorder, level);
  43                 if (root->rlink != NULL)
  44                         trecurse(root->rlink, action, level + 1);
  45                 (*action)(root, endorder, level);
  46         }
  47 }
  48
  49 /* Walk the nodes of a tree
  50  *
  51  * Parameters:
  52  *      vroot:  Root of the tree to be walked
  53  */
  54 void
  55 twalk(const void *vroot,
  56       void (*action)(const void *, VISIT, int))
  57 {
  58         if (vroot != NULL && action != NULL)
  59                 trecurse(vroot, action, 0);
  60 }