71 lines
3.1 KiB
C
Executable File
71 lines
3.1 KiB
C
Executable File
/* Sequential list data type implemented by a binary tree.
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Copyright (C) 2006, 2009-2024 Free Software Foundation, Inc.
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Written by Bruno Haible <bruno@clisp.org>, 2006.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Common code of gl_avltree_list.c and gl_avltreehash_list.c. */
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/* An AVL tree is a binary tree where
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1. The height of each node is calculated as
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heightof(node) = 1 + max (heightof(node.left), heightof(node.right)).
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2. The heights of the subtrees of each node differ by at most 1:
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| heightof(right) - heightof(left) | <= 1.
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3. The index of the elements in the node.left subtree are smaller than
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the index of node.
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The index of the elements in the node.right subtree are larger than
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the index of node.
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*/
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/* -------------------------- gl_list_t Data Type -------------------------- */
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/* Concrete list node implementation, valid for this file only. */
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struct gl_list_node_impl
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{
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#if WITH_HASHTABLE
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struct gl_hash_entry h; /* hash table entry fields; must be first */
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#endif
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struct gl_list_node_impl *left; /* left branch, or NULL */
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struct gl_list_node_impl *right; /* right branch, or NULL */
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/* Parent pointer, or NULL. The parent pointer is not needed for most
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operations. It is needed so that a gl_list_node_t can be returned
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without memory allocation, on which the functions gl_list_remove_node,
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gl_list_add_before, gl_list_add_after can be implemented. */
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struct gl_list_node_impl *parent;
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int balance; /* heightof(right) - heightof(left),
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always = -1 or 0 or 1 */
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size_t branch_size; /* number of nodes in this branch,
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= branchsize(left)+branchsize(right)+1 */
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const void *value;
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};
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/* Concrete gl_list_impl type, valid for this file only. */
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struct gl_list_impl
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{
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struct gl_list_impl_base base;
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#if WITH_HASHTABLE
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/* A hash table: managed as an array of collision lists. */
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struct gl_hash_entry **table;
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size_t table_size;
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#endif
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struct gl_list_node_impl *root; /* root node or NULL */
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};
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/* An AVL tree of height h has at least F_(h+2) - 1 [Fibonacci number] and at
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most 2^h - 1 elements. So, h <= 84 (because a tree of height h >= 85 would
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have at least F_87 - 1 elements, and because even on 64-bit machines,
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sizeof (gl_list_node_impl) * (F_87 - 1) > 2^64
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this would exceed the address space of the machine. */
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#define MAXHEIGHT 83
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