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33 * AVL tree implementation.
35 * This binary search tree implementation allows average O(1) insertion and
36 * removal of elements (excluding binary search time).
39 * @author Olaf Wintermann
46 #include "allocator.h"
58 typedef struct UcxAVLNode UcxAVLNode;
65 * The key for this node.
69 * Data contained by this node.
73 * The height of this (sub)-tree.
81 * Root node of left subtree.
85 * Root node of right subtree.
95 * The UcxAllocator that shall be used to manage the memory for node data.
97 UcxAllocator *allocator;
99 * Root node of the tree.
103 * Compare function that shall be used to compare the UcxAVLNode keys.
104 * @see UcxAVLNode.key
109 * This data will also be provided to the cmpfunc.
115 * Initializes a new UcxAVLTree with a default allocator.
117 * @param cmpfunc the compare function that shall be used
118 * @return a new UcxAVLTree object
119 * @see ucx_avl_new_a()
121 UcxAVLTree *ucx_avl_new(cmp_func cmpfunc);
124 * Initializes a new UcxAVLTree with the specified allocator.
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.
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
134 UcxAVLTree *ucx_avl_new_a(cmp_func cmpfunc, UcxAllocator *allocator);
137 * Destroys a UcxAVLTree.
139 * Note, that the contents are not automatically freed.
140 * Use may use #ucx_avl_free_content() before calling this function.
142 * @param tree the tree to destroy
143 * @see ucx_avl_free_content()
145 void ucx_avl_free(UcxAVLTree *tree);
148 * Frees the contents of a UcxAVLTree.
150 * This is a convenience function that iterates over the tree and passes all
151 * values to the specified destructor function.
153 * If no destructor is specified (<code>NULL</code>), the free() function of
154 * the tree's own allocator is used.
156 * You must ensure, that it is valid to pass each value in the map to the same
157 * destructor function.
159 * You should free the entire tree afterwards, as the contents will be invalid.
161 * @param tree for which the contents shall be freed
162 * @param destr optional pointer to a destructor function
163 * @see ucx_avl_free()
165 void ucx_avl_free_content(UcxAVLTree *tree, ucx_destructor destr);
168 * Macro for initializing a new UcxAVLTree with the default allocator and a
169 * ucx_cmp_ptr() compare function.
171 * @return a new default UcxAVLTree object
173 #define ucx_avl_default_new() \
174 ucx_avl_new_a(ucx_cmp_ptr, ucx_default_allocator())
177 * Gets the node from the tree, that is associated with the specified key.
178 * @param tree the UcxAVLTree
180 * @return the node (or <code>NULL</code>, if the key is not present)
182 UcxAVLNode *ucx_avl_get_node(UcxAVLTree *tree, intptr_t key);
185 * Gets the value from the tree, that is associated with the specified key.
186 * @param tree the UcxAVLTree
188 * @return the value (or <code>NULL</code>, if the key is not present)
190 void *ucx_avl_get(UcxAVLTree *tree, intptr_t key);
193 * A mode for #ucx_avl_find_node() with the same behavior as
194 * #ucx_avl_get_node().
196 #define UCX_AVL_FIND_EXACT 0
198 * A mode for #ucx_avl_find_node() finding the node whose key is at least
199 * as large as the specified key.
201 #define UCX_AVL_FIND_LOWER_BOUNDED 1
203 * A mode for #ucx_avl_find_node() finding the node whose key is at most
204 * as large as the specified key.
206 #define UCX_AVL_FIND_UPPER_BOUNDED 2
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
213 #define UCX_AVL_FIND_CLOSEST 3
216 * Finds a node within the tree. The following modes are supported:
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
229 * The distance function provided MUST agree with the compare function of
232 * @param tree the UcxAVLTree
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)
238 UcxAVLNode *ucx_avl_find_node(UcxAVLTree *tree, intptr_t key,
239 distance_func dfnc, int mode);
242 * Finds a value within the tree.
243 * See #ucx_avl_find_node() for details.
245 * @param tree the UcxAVLTree
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)
251 void *ucx_avl_find(UcxAVLTree *tree, intptr_t key,
252 distance_func dfnc, int mode);
255 * Puts a key/value pair into the tree.
257 * Attention: use this function only, if a possible old value does not need
260 * @param tree the UcxAVLTree
262 * @param value the new value
263 * @return zero, if and only if the operation succeeded
265 int ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value);
268 * Puts a key/value pair into the tree.
270 * This is a secure function which saves the old value to the variable pointed
273 * @param tree the UcxAVLTree
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
280 int ucx_avl_put_s(UcxAVLTree *tree, intptr_t key, void *value, void **oldvalue);
283 * Removes a node from the AVL tree.
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.
289 * @param tree the UcxAVLTree
290 * @param node the node to remove
291 * @return zero, if and only if an element has been removed
293 int ucx_avl_remove_node(UcxAVLTree *tree, UcxAVLNode *node);
296 * Removes an element from the AVL tree.
298 * @param tree the UcxAVLTree
300 * @return zero, if and only if an element has been removed
302 int ucx_avl_remove(UcxAVLTree *tree, intptr_t key);
305 * Removes an element from the AVL tree.
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).
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).
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
318 * @param oldvalue optional: a pointer to the location where the old value
320 * @return zero, if and only if an element has been removed
322 int ucx_avl_remove_s(UcxAVLTree *tree, intptr_t key,
323 intptr_t *oldkey, void **oldvalue);
326 * Counts the nodes in the specified UcxAVLTree.
327 * @param tree the AVL tree
328 * @return the node count
330 size_t ucx_avl_count(UcxAVLTree *tree);
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
338 UcxAVLNode* ucx_avl_pred(UcxAVLNode* node);
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
346 UcxAVLNode* ucx_avl_succ(UcxAVLNode* node);
352 #endif /* UCX_AVL_H */