1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2016 Olaf Wintermann. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29
30 /**
31 * @file avl.h
32 *
33 * AVL tree implementation.
34 *
35 * This binary search tree implementation allows average O(1) insertion and
36 * removal of elements (excluding binary search time).
37 *
38 * @author Mike Becker
39 * @author Olaf Wintermann
40 */
41
42 #ifndef UCX_AVL_H
43 #define UCX_AVL_H
44
45 #include "ucx.h"
46 #include "allocator.h"
47 #include <inttypes.h>
48
49 #ifdef __cplusplus
50 extern "C" {
51 #endif
52
53 /**
54 * UCX AVL Node type.
55 *
56 * @see UcxAVLNode
57 */
58 typedef struct UcxAVLNode UcxAVLNode;
59
60 /**
61 * UCX AVL Node.
62 */
63 struct UcxAVLNode {
64 /**
65 * The key for this node.
66 */
67 intptr_t key;
68 /**
69 * Data contained by this node.
70 */
71 void *value;
72 /**
73 * The height of this (sub)-tree.
74 */
75 size_t height;
76 /**
77 * Parent node.
78 */
79 UcxAVLNode *parent;
80 /**
81 * Root node of left subtree.
82 */
83 UcxAVLNode *left;
84 /**
85 * Root node of right subtree.
86 */
87 UcxAVLNode *right;
88 };
89
90 /**
91 * UCX AVL Tree.
92 */
93 typedef struct {
94 /**
95 * The UcxAllocator that shall be used to manage the memory for node data.
96 */
97 UcxAllocator *allocator;
98 /**
99 * Root node of the tree.
100 */
101 UcxAVLNode *root;
102 /**
103 * Compare function that shall be used to compare the UcxAVLNode keys.
104 * @see UcxAVLNode.key
105 */
106 cmp_func cmpfunc;
107 /**
108 * Custom user data.
109 * This data will also be provided to the cmpfunc.
110 */
111 void *userdata;
112 } UcxAVLTree;
113
114 /**
115 * Initializes a new UcxAVLTree with a default allocator.
116 *
117 * @param cmpfunc the compare function that shall be used
118 * @return a new UcxAVLTree object
119 * @see ucx_avl_new_a()
120 */
121 UcxAVLTree *ucx_avl_new(cmp_func cmpfunc);
122
123 /**
124 * Initializes a new UcxAVLTree with the specified allocator.
125 *
126 * The cmpfunc should be capable of comparing two keys within this AVL tree.
127 * So if you want to use null terminated strings as keys, you could use the
128 * ucx_strcmp() function here.
129 *
130 * @param cmpfunc the compare function that shall be used
131 * @param allocator the UcxAllocator that shall be used
132 * @return a new UcxAVLTree object
133 */
134 UcxAVLTree *ucx_avl_new_a(cmp_func cmpfunc, UcxAllocator *allocator);
135
136 /**
137 * Destroys a UcxAVLTree.
138 * @param tree the tree to destroy
139 */
140 void ucx_avl_free(UcxAVLTree *tree);
141
142 /**
143 * Macro for initializing a new UcxAVLTree with the default allocator and a
144 * ucx_ptrcmp() compare function.
145 *
146 * @return a new default UcxAVLTree object
147 */
148 #define ucx_avl_default_new() ucx_avl_new_a(ucx_ptrcmp, ucx_default_allocator())
149
150 /**
151 * Gets the node from the tree, that is associated with the specified key.
152 * @param tree the UcxAVLTree
153 * @param key the key
154 * @return the node (or <code>NULL</code>, if the key is not present)
155 */
156 UcxAVLNode *ucx_avl_get_node(UcxAVLTree *tree, intptr_t key);
157
158 /**
159 * Gets the value from the tree, that is associated with the specified key.
160 * @param tree the UcxAVLTree
161 * @param key the key
162 * @return the value (or <code>NULL</code>, if the key is not present)
163 */
164 void *ucx_avl_get(UcxAVLTree *tree, intptr_t key);
165
166 /**
167 * Puts a key/value pair into the tree.
168 *
169 * Attention: use this function only, if a possible old value does not need
170 * to be preserved.
171 *
172 * @param tree the UcxAVLTree
173 * @param key the key
174 * @param value the new value
175 * @return zero, if and only if the operation succeeded
176 */
177 int ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value);
178
179 /**
180 * Puts a key/value pair into the tree.
181 *
182 * This is a secure function which saves the old value to the variable pointed
183 * at by oldvalue.
184 *
185 * @param tree the UcxAVLTree
186 * @param key the key
187 * @param value the new value
188 * @param oldvalue optional: a pointer to the location where a possible old
189 * value shall be stored
190 * @return zero, if and only if the operation succeeded
191 */
192 int ucx_avl_put_s(UcxAVLTree *tree, intptr_t key, void *value, void **oldvalue);
193
194 /**
195 * Removes a node from the AVL tree.
196 *
197 * Note: the specified node is logically removed. The tree implementation
198 * decides which memory area is freed. In most cases the here provided node
199 * is freed, so it's further use is generally undefined.
200 *
201 * @param tree the UcxAVLTree
202 * @param node the node to remove
203 * @return zero, if and only if an element has been removed
204 */
205 int ucx_avl_remove_node(UcxAVLTree *tree, UcxAVLNode *node);
206
207 /**
208 * Removes an element from the AVL tree.
209 *
210 * @param tree the UcxAVLTree
211 * @param key the key
212 * @return zero, if and only if an element has been removed
213 */
214 int ucx_avl_remove(UcxAVLTree *tree, intptr_t key);
215
216 /**
217 * Removes an element from the AVL tree.
218 *
219 * This is a secure function which saves the old key and value data from node
220 * to the variables at the location of oldkey and oldvalue (if specified), so
221 * they can be freed afterwards (if necessary).
222 *
223 * Note: the returned key in oldkey is possibly not the same as the provided
224 * key for the lookup (in terms of memory location).
225 *
226 * @param tree the UcxAVLTree
227 * @param key the key of the element to remove
228 * @param oldkey optional: a pointer to the location where the old key shall be
229 * stored
230 * @param oldvalue optional: a pointer to the location where the old value
231 * shall be stored
232 * @return zero, if and only if an element has been removed
233 */
234 int ucx_avl_remove_s(UcxAVLTree *tree, intptr_t key,
235 intptr_t *oldkey, void **oldvalue);
236
237 /**
238 * Counts the nodes in the specified UcxAVLTree.
239 * @param tree the AVL tree
240 * @return the node count
241 */
242 size_t ucx_avl_count(UcxAVLTree *tree);
243
244 #ifdef __cplusplus
245 }
246 #endif
247
248 #endif /* UCX_AVL_H */
249
250