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comparison: src/ucx/avl.h

src/ucx/avl.h

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1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2017 Mike Becker, 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_cmp_str() 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 *
139 * Note, that the contents are not automatically freed.
140 * Use may use #ucx_avl_free_content() before calling this function.
141 *
142 * @param tree the tree to destroy
143 * @see ucx_avl_free_content()
144 */
145 void ucx_avl_free(UcxAVLTree *tree);
146
147 /**
148 * Frees the contents of a UcxAVLTree.
149 *
150 * This is a convenience function that iterates over the tree and passes all
151 * values to the specified destructor function.
152 *
153 * If no destructor is specified (<code>NULL</code>), the free() function of
154 * the tree's own allocator is used.
155 *
156 * You must ensure, that it is valid to pass each value in the map to the same
157 * destructor function.
158 *
159 * You should free the entire tree afterwards, as the contents will be invalid.
160 *
161 * @param tree for which the contents shall be freed
162 * @param destr optional pointer to a destructor function
163 * @see ucx_avl_free()
164 */
165 void ucx_avl_free_content(UcxAVLTree *tree, ucx_destructor destr);
166
167 /**
168 * Macro for initializing a new UcxAVLTree with the default allocator and a
169 * ucx_cmp_ptr() compare function.
170 *
171 * @return a new default UcxAVLTree object
172 */
173 #define ucx_avl_default_new() \
174 ucx_avl_new_a(ucx_cmp_ptr, ucx_default_allocator())
175
176 /**
177 * Gets the node from the tree, that is associated with the specified key.
178 * @param tree the UcxAVLTree
179 * @param key the key
180 * @return the node (or <code>NULL</code>, if the key is not present)
181 */
182 UcxAVLNode *ucx_avl_get_node(UcxAVLTree *tree, intptr_t key);
183
184 /**
185 * Gets the value from the tree, that is associated with the specified key.
186 * @param tree the UcxAVLTree
187 * @param key the key
188 * @return the value (or <code>NULL</code>, if the key is not present)
189 */
190 void *ucx_avl_get(UcxAVLTree *tree, intptr_t key);
191
192 /**
193 * A mode for #ucx_avl_find_node() with the same behavior as
194 * #ucx_avl_get_node().
195 */
196 #define UCX_AVL_FIND_EXACT 0
197 /**
198 * A mode for #ucx_avl_find_node() finding the node whose key is at least
199 * as large as the specified key.
200 */
201 #define UCX_AVL_FIND_LOWER_BOUNDED 1
202 /**
203 * A mode for #ucx_avl_find_node() finding the node whose key is at most
204 * as large as the specified key.
205 */
206 #define UCX_AVL_FIND_UPPER_BOUNDED 2
207 /**
208 * A mode for #ucx_avl_find_node() finding the node with a key that is as close
209 * to the specified key as possible. If the key is present, the behavior is
210 * like #ucx_avl_get_node(). This mode only returns <code>NULL</code> on
211 * empty trees.
212 */
213 #define UCX_AVL_FIND_CLOSEST 3
214
215 /**
216 * Finds a node within the tree. The following modes are supported:
217 * <ul>
218 * <li>#UCX_AVL_FIND_EXACT: the same behavior as #ucx_avl_get_node()</li>
219 * <li>#UCX_AVL_FIND_LOWER_BOUNDED: finds the node whose key is at least
220 * as large as the specified key</li>
221 * <li>#UCX_AVL_FIND_UPPER_BOUNDED: finds the node whose key is at most
222 * as large as the specified key</li>
223 * <li>#UCX_AVL_FIND_CLOSEST: finds the node with a key that is as close to
224 * the specified key as possible. If the key is present, the behavior is
225 * like #ucx_avl_get_node(). This mode only returns <code>NULL</code> on
226 * empty trees.</li>
227 * </ul>
228 *
229 * The distance function provided MUST agree with the compare function of
230 * the AVL tree.
231 *
232 * @param tree the UcxAVLTree
233 * @param key the key
234 * @param dfnc the distance function
235 * @param mode the find mode
236 * @return the node (or <code>NULL</code>, if no node can be found)
237 */
238 UcxAVLNode *ucx_avl_find_node(UcxAVLTree *tree, intptr_t key,
239 distance_func dfnc, int mode);
240
241 /**
242 * Finds a value within the tree.
243 * See #ucx_avl_find_node() for details.
244 *
245 * @param tree the UcxAVLTree
246 * @param key the key
247 * @param dfnc the distance function
248 * @param mode the find mode
249 * @return the value (or <code>NULL</code>, if no value can be found)
250 */
251 void *ucx_avl_find(UcxAVLTree *tree, intptr_t key,
252 distance_func dfnc, int mode);
253
254 /**
255 * Puts a key/value pair into the tree.
256 *
257 * Attention: use this function only, if a possible old value does not need
258 * to be preserved.
259 *
260 * @param tree the UcxAVLTree
261 * @param key the key
262 * @param value the new value
263 * @return zero, if and only if the operation succeeded
264 */
265 int ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value);
266
267 /**
268 * Puts a key/value pair into the tree.
269 *
270 * This is a secure function which saves the old value to the variable pointed
271 * at by oldvalue.
272 *
273 * @param tree the UcxAVLTree
274 * @param key the key
275 * @param value the new value
276 * @param oldvalue optional: a pointer to the location where a possible old
277 * value shall be stored
278 * @return zero, if and only if the operation succeeded
279 */
280 int ucx_avl_put_s(UcxAVLTree *tree, intptr_t key, void *value, void **oldvalue);
281
282 /**
283 * Removes a node from the AVL tree.
284 *
285 * Note: the specified node is logically removed. The tree implementation
286 * decides which memory area is freed. In most cases the here provided node
287 * is freed, so its further use is generally undefined.
288 *
289 * @param tree the UcxAVLTree
290 * @param node the node to remove
291 * @return zero, if and only if an element has been removed
292 */
293 int ucx_avl_remove_node(UcxAVLTree *tree, UcxAVLNode *node);
294
295 /**
296 * Removes an element from the AVL tree.
297 *
298 * @param tree the UcxAVLTree
299 * @param key the key
300 * @return zero, if and only if an element has been removed
301 */
302 int ucx_avl_remove(UcxAVLTree *tree, intptr_t key);
303
304 /**
305 * Removes an element from the AVL tree.
306 *
307 * This is a secure function which saves the old key and value data from node
308 * to the variables at the location of oldkey and oldvalue (if specified), so
309 * they can be freed afterwards (if necessary).
310 *
311 * Note: the returned key in oldkey is possibly not the same as the provided
312 * key for the lookup (in terms of memory location).
313 *
314 * @param tree the UcxAVLTree
315 * @param key the key of the element to remove
316 * @param oldkey optional: a pointer to the location where the old key shall be
317 * stored
318 * @param oldvalue optional: a pointer to the location where the old value
319 * shall be stored
320 * @return zero, if and only if an element has been removed
321 */
322 int ucx_avl_remove_s(UcxAVLTree *tree, intptr_t key,
323 intptr_t *oldkey, void **oldvalue);
324
325 /**
326 * Counts the nodes in the specified UcxAVLTree.
327 * @param tree the AVL tree
328 * @return the node count
329 */
330 size_t ucx_avl_count(UcxAVLTree *tree);
331
332 /**
333 * Finds the in-order predecessor of the given node.
334 * @param node an AVL node
335 * @return the in-order predecessor of the given node, or <code>NULL</code> if
336 * the given node is the in-order minimum
337 */
338 UcxAVLNode* ucx_avl_pred(UcxAVLNode* node);
339
340 /**
341 * Finds the in-order successor of the given node.
342 * @param node an AVL node
343 * @return the in-order successor of the given node, or <code>NULL</code> if
344 * the given node is the in-order maximum
345 */
346 UcxAVLNode* ucx_avl_succ(UcxAVLNode* node);
347
348 #ifdef __cplusplus
349 }
350 #endif
351
352 #endif /* UCX_AVL_H */
353

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