4.9.3.6 Initialization by Copying

This function copies one traverser to another. It only copies the stack of parent pointers if they are up-to-date:

69. <BST traverser copy initializer 69> =
void *
bst_t_copy (struct bst_traverser *trav, const struct bst_traverser *src) 
{
  assert (trav != NULL && src != NULL);

  if (trav != src) 
    {
      trav->bst_table = src->bst_table;
      trav->bst_node = src->bst_node;
      trav->bst_generation = src->bst_generation;
      if (trav->bst_generation == trav->bst_table->bst_generation) 
        {
          trav->bst_height = src->bst_height;
          memcpy (trav->bst_stack, (const void *) src->bst_stack,
                  sizeof *trav->bst_stack * trav->bst_height);
        }
    }

  return trav->bst_node != NULL ? trav->bst_node->bst_data : NULL;
}

This code is included in 63 and 178.

Exercises:

1. Without the check that trav != src before copying src into trav, what might happen? [answer]