tsearch/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 <assert.h>
  15 #define _SEARCH_PRIVATE
  16 #include <tsearch/search.h>
  17 #include <stdlib.h>
  18
  19 static void trecurse (const node_t *, void (*action)(const void *, VISIT, int),
  20                       int level)  __MINGW_ATTRIB_NONNULL (1)
  21                                   __MINGW_ATTRIB_NONNULL (2);
  22 /* Walk the nodes of a tree */
  23 static void
  24 trecurse( const node_t *root,   /* Root of the tree to be walked */
  25         void (*action)(const void *, VISIT, int),
  26         int level)
  27 {
  28         if (root->llink == NULL && root->rlink == NULL)
  29                 (*action)(root, leaf, level);
  30         else {
  31                 (*action)(root, preorder, level);
  32                 if (root->llink != NULL)
  33                         trecurse(root->llink, action, level + 1);
  34                 (*action)(root, postorder, level);
  35                 if (root->rlink != NULL)
  36                         trecurse(root->rlink, action, level + 1);
  37                 (*action)(root, endorder, level);
  38         }
  39 }
  40
  41 /* Walk the nodes of a tree */
  42 void
  43 twalk( const void *vroot,       /* Root of the tree to be walked */
  44         void (*action) (const void *, VISIT, int))
  45 {
  46         if (vroot != NULL && action != NULL)
  47                 trecurse(vroot, action, 0);
  48 }