| /* Sequential list data type implemented by a binary tree. |
| Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc. |
| Written by Bruno Haible <bruno@clisp.org>, 2006. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| /* Common code of gl_avltree_list.c and gl_avltreehash_list.c. */ |
| |
| /* An AVL tree is a binary tree where |
| 1. The height of each node is calculated as |
| heightof(node) = 1 + max (heightof(node.left), heightof(node.right)). |
| 2. The heights of the subtrees of each node differ by at most 1: |
| | heightof(right) - heightof(left) | <= 1. |
| 3. The index of the elements in the node.left subtree are smaller than |
| the index of node. |
| The index of the elements in the node.right subtree are larger than |
| the index of node. |
| */ |
| |
| /* -------------------------- gl_list_t Data Type -------------------------- */ |
| |
| /* Concrete list node implementation, valid for this file only. */ |
| struct gl_list_node_impl |
| { |
| #if WITH_HASHTABLE |
| struct gl_hash_entry h; /* hash table entry fields; must be first */ |
| #endif |
| struct gl_list_node_impl *left; /* left branch, or NULL */ |
| struct gl_list_node_impl *right; /* right branch, or NULL */ |
| /* Parent pointer, or NULL. The parent pointer is not needed for most |
| operations. It is needed so that a gl_list_node_t can be returned |
| without memory allocation, on which the functions gl_list_remove_node, |
| gl_list_add_before, gl_list_add_after can be implemented. */ |
| struct gl_list_node_impl *parent; |
| int balance; /* heightof(right) - heightof(left), |
| always = -1 or 0 or 1 */ |
| size_t branch_size; /* number of nodes in this branch, |
| = branchsize(left)+branchsize(right)+1 */ |
| const void *value; |
| }; |
| |
| /* Concrete gl_list_impl type, valid for this file only. */ |
| struct gl_list_impl |
| { |
| struct gl_list_impl_base base; |
| #if WITH_HASHTABLE |
| /* A hash table: managed as an array of collision lists. */ |
| struct gl_hash_entry **table; |
| size_t table_size; |
| #endif |
| struct gl_list_node_impl *root; /* root node or NULL */ |
| }; |
| |
| /* An AVL tree of height h has at least F_(h+2) - 1 [Fibonacci number] and at |
| most 2^h - 1 elements. So, h <= 84 (because a tree of height h >= 85 would |
| have at least F_87 - 1 elements, and because even on 64-bit machines, |
| sizeof (gl_list_node_impl) * (F_87 - 1) > 2^64 |
| this would exceed the address space of the machine. */ |
| #define MAXHEIGHT 83 |