newlib/libc/search/twalk.c

   1 /*      $NetBSD: twalk.c,v 1.1 1999/02/22 10:33:16 christos 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 0
  16 #if defined(LIBC_SCCS) && !defined(lint)
  17 __RCSID("$NetBSD: twalk.c,v 1.1 1999/02/22 10:33:16 christos Exp $");
  18 #endif /* LIBC_SCCS and not lint */
  19 #endif
  20
  21 #include <assert.h>
  22 #define _SEARCH_PRIVATE
  23 #include <search.h>
  24 #include <stdlib.h>
  25
  26 static void trecurse(const node_t *,
  27     void (*action)(const void *, VISIT, int), int level);
  28
  29 /* Walk the nodes of a tree */
  30 static void
  31 trecurse(
  32         const node_t *root,     /* Root of the tree to be walked */
  33         void (*action)(const void *, VISIT, int),
  34         int level
  35 )
  36 {
  37
  38         if (root->llink == NULL && root->rlink == NULL)
  39                 (*action)(root, leaf, level);
  40         else {
  41                 (*action)(root, preorder, level);
  42                 if (root->llink != NULL)
  43                         trecurse(root->llink, action, level + 1);
  44                 (*action)(root, postorder, level);
  45                 if (root->rlink != NULL)
  46                         trecurse(root->rlink, action, level + 1);
  47                 (*action)(root, endorder, level);
  48         }
  49 }
  50
  51 /* Walk the nodes of a tree */
  52 void
  53 twalk (const void *vroot,       /* Root of the tree to be walked */
  54         void (*action)(const void *, VISIT, int))
  55 {
  56         if (vroot != NULL && action != NULL)
  57                 trecurse(vroot, action, 0);
  58 }