1  /* Sequential list data type implemented by a binary tree.
       2     Copyright (C) 2006, 2009-2021 Free Software Foundation, Inc.
       3     Written by Bruno Haible <bruno@clisp.org>, 2006.
       4  
       5     This file is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU Lesser General Public License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     License, or (at your option) any later version.
       9  
      10     This file is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  /* Common code of gl_avltree_list.c, gl_rbtree_list.c,
      19                    gl_avltreehash_list.c, gl_rbtreehash_list.c.  */
      20  
      21  /* An item on the stack used for iterating across the elements.  */
      22  typedef struct
      23  {
      24    gl_list_node_t node;
      25    size_t rightp;
      26  } iterstack_item_t;
      27  
      28  /* A stack used for iterating across the elements.  */
      29  typedef iterstack_item_t iterstack_t[MAXHEIGHT];
      30  
      31  /* Frees a non-empty subtree recursively.
      32     This function is recursive and therefore not very fast.  */
      33  static void
      34  free_subtree (gl_list_node_t node)
      35  {
      36    if (node->left != NULL)
      37      free_subtree (node->left);
      38    if (node->right != NULL)
      39      free_subtree (node->right);
      40    free (node);
      41  }