/* Searches for |item| in |tree|.
   If found, initializes |trav| to the item found and returns the item
   as well.
   If there is no matching item, initializes |trav| to the null item
   and returns |NULL|. */
void *
bst_t_find (struct bst_traverser *trav, struct bst_table *tree, void *item)
{
  struct bst_node *p, *q;

  assert (trav != NULL && tree != NULL && item != NULL);
  trav->bst_table = tree;
  trav->bst_height = 0;
  trav->bst_generation = tree->bst_generation;
  for (p = tree->bst_root; p != NULL; p = q)
    {
      int cmp = tree->bst_compare (item, p->bst_data, tree->bst_param);

      if (cmp < 0)
        q = p->bst_link[0];
      else if (cmp > 0)
        q = p->bst_link[1];
      else /* |cmp == 0| */
        {
          trav->bst_node = p;
          return p->bst_data;
        }

      if (trav->bst_height >= BST_MAX_HEIGHT)
        {
          bst_balance (trav->bst_table);
          return bst_t_find (trav, tree, item);
        }
      trav->bst_stack[trav->bst_height++] = p;
    }

  trav->bst_height = 0;
  trav->bst_node = NULL;
  return NULL;
}