diff -r b7d1317b138e -r fae240d633fc src/ucx/avl.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ucx/avl.h	Tue Oct 17 16:15:41 2017 +0200
@@ -0,0 +1,327 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2017 Olaf Wintermann. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+/**
+ * @file avl.h
+ * 
+ * AVL tree implementation.
+ * 
+ * This binary search tree implementation allows average O(1) insertion and
+ * removal of elements (excluding binary search time).
+ * 
+ * @author Mike Becker
+ * @author Olaf Wintermann
+ */
+
+#ifndef UCX_AVL_H
+#define UCX_AVL_H
+
+#include <ucx/ucx.h>
+#include <ucx/allocator.h>
+#include <inttypes.h>
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+/**
+ * UCX AVL Node type.
+ * 
+ * @see UcxAVLNode
+ */
+typedef struct UcxAVLNode UcxAVLNode;
+
+/**
+ * UCX AVL Node.
+ */
+struct UcxAVLNode {
+    /**
+     * The key for this node.
+     */
+    intptr_t key;
+    /**
+     * Data contained by this node.
+     */
+    void *value;
+    /**
+     * The height of this (sub)-tree.
+     */
+    size_t height;
+    /**
+     * Parent node.
+     */
+    UcxAVLNode *parent;
+    /**
+     * Root node of left subtree.
+     */
+    UcxAVLNode *left;
+    /**
+     * Root node of right subtree.
+     */
+    UcxAVLNode *right;
+};
+
+/**
+ * UCX AVL Tree.
+ */
+typedef struct {
+    /**
+     * The UcxAllocator that shall be used to manage the memory for node data.
+     */
+    UcxAllocator *allocator;
+    /**
+     * Root node of the tree.
+     */
+    UcxAVLNode *root;
+    /**
+     * Compare function that shall be used to compare the UcxAVLNode keys.
+     * @see UcxAVLNode.key
+     */
+    cmp_func cmpfunc;
+    /**
+     * Custom user data.
+     * This data will also be provided to the cmpfunc.
+     */
+    void *userdata;
+} UcxAVLTree;
+
+/**
+ * Initializes a new UcxAVLTree with a default allocator.
+ * 
+ * @param cmpfunc the compare function that shall be used
+ * @return a new UcxAVLTree object
+ * @see ucx_avl_new_a()
+ */
+UcxAVLTree *ucx_avl_new(cmp_func cmpfunc);
+
+/**
+ * Initializes a new UcxAVLTree with the specified allocator.
+ * 
+ * The cmpfunc should be capable of comparing two keys within this AVL tree.
+ * So if you want to use null terminated strings as keys, you could use the
+ * ucx_strcmp() function here.
+ * 
+ * @param cmpfunc the compare function that shall be used
+ * @param allocator the UcxAllocator that shall be used
+ * @return a new UcxAVLTree object
+ */
+UcxAVLTree *ucx_avl_new_a(cmp_func cmpfunc, UcxAllocator *allocator);
+
+/**
+ * Destroys a UcxAVLTree.
+ * @param tree the tree to destroy
+ */
+void ucx_avl_free(UcxAVLTree *tree);
+
+/**
+ * Macro for initializing a new UcxAVLTree with the default allocator and a
+ * ucx_ptrcmp() compare function.
+ * 
+ * @return a new default UcxAVLTree object
+ */
+#define ucx_avl_default_new() ucx_avl_new_a(ucx_ptrcmp, ucx_default_allocator())
+
+/**
+ * Gets the node from the tree, that is associated with the specified key.
+ * @param tree the UcxAVLTree
+ * @param key the key
+ * @return the node (or <code>NULL</code>, if the key is not present)
+ */
+UcxAVLNode *ucx_avl_get_node(UcxAVLTree *tree, intptr_t key);
+
+/**
+ * Gets the value from the tree, that is associated with the specified key.
+ * @param tree the UcxAVLTree
+ * @param key the key
+ * @return the value (or <code>NULL</code>, if the key is not present)
+ */
+void *ucx_avl_get(UcxAVLTree *tree, intptr_t key);
+
+/**
+ * A mode for #ucx_avl_find_node() with the same behavior as
+ * #ucx_avl_get_node().
+ */
+#define UCX_AVL_FIND_EXACT         0
+/**
+ * A mode for #ucx_avl_find_node() finding the node whose key is at least
+ * as large as the specified key.
+ */
+#define UCX_AVL_FIND_LOWER_BOUNDED 1
+/**
+ * A mode for #ucx_avl_find_node() finding the node whose key is at most
+ * as large as the specified key.
+ */
+#define UCX_AVL_FIND_UPPER_BOUNDED 2
+/**
+ * A mode for #ucx_avl_find_node() finding the node with a key that is as close
+ * to the specified key as possible. If the key is present, the behavior is
+ * like #ucx_avl_get_node(). This mode only returns <code>NULL</code> on
+ * empty trees.
+ */
+#define UCX_AVL_FIND_CLOSEST       3
+
+/**
+ * Finds a node within the tree. The following modes are supported:
+ * <ul>
+ * <li>#UCX_AVL_FIND_EXACT: the same behavior as #ucx_avl_get_node()</li>
+ * <li>#UCX_AVL_FIND_LOWER_BOUNDED: finds the node whose key is at least
+ * as large as the specified key</li>
+ * <li>#UCX_AVL_FIND_UPPER_BOUNDED: finds the node whose key is at most
+ * as large as the specified key</li>
+ * <li>#UCX_AVL_FIND_CLOSEST: finds the node with a key that is as close to
+ * the specified key as possible. If the key is present, the behavior is
+ * like #ucx_avl_get_node(). This mode only returns <code>NULL</code> on
+ * empty trees.</li> 
+ * </ul>
+ * 
+ * The distance function provided MUST agree with the compare function of
+ * the AVL tree.
+ * 
+ * @param tree the UcxAVLTree
+ * @param key the key
+ * @param dfnc the distance function
+ * @param mode the find mode
+ * @return the node (or <code>NULL</code>, if no node can be found)
+ */
+UcxAVLNode *ucx_avl_find_node(UcxAVLTree *tree, intptr_t key,
+        distance_func dfnc, int mode);
+
+/**
+ * Finds a value within the tree.
+ * See #ucx_avl_find_node() for details.
+ * 
+ * @param tree the UcxAVLTree
+ * @param key the key
+ * @param dfnc the distance function
+ * @param mode the find mode
+ * @return the value (or <code>NULL</code>, if no value can be found)
+ */
+void *ucx_avl_find(UcxAVLTree *tree, intptr_t key,
+        distance_func dfnc, int mode);
+
+/**
+ * Puts a key/value pair into the tree.
+ * 
+ * Attention: use this function only, if a possible old value does not need
+ * to be preserved.
+ * 
+ * @param tree the UcxAVLTree
+ * @param key the key
+ * @param value the new value
+ * @return zero, if and only if the operation succeeded
+ */
+int ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value);
+
+/**
+ * Puts a key/value pair into the tree.
+ * 
+ * This is a secure function which saves the old value to the variable pointed
+ * at by oldvalue.
+ * 
+ * @param tree the UcxAVLTree
+ * @param key the key
+ * @param value the new value
+ * @param oldvalue optional: a pointer to the location where a possible old
+ * value shall be stored
+ * @return zero, if and only if the operation succeeded
+ */
+int ucx_avl_put_s(UcxAVLTree *tree, intptr_t key, void *value, void **oldvalue);
+
+/**
+ * Removes a node from the AVL tree.
+ * 
+ * Note: the specified node is logically removed. The tree implementation
+ * decides which memory area is freed. In most cases the here provided node
+ * is freed, so its further use is generally undefined.
+ * 
+ * @param tree the UcxAVLTree
+ * @param node the node to remove
+ * @return zero, if and only if an element has been removed
+ */
+int ucx_avl_remove_node(UcxAVLTree *tree, UcxAVLNode *node);
+
+/**
+ * Removes an element from the AVL tree.
+ * 
+ * @param tree the UcxAVLTree
+ * @param key the key
+ * @return zero, if and only if an element has been removed
+ */
+int ucx_avl_remove(UcxAVLTree *tree, intptr_t key);
+
+/**
+ * Removes an element from the AVL tree.
+ * 
+ * This is a secure function which saves the old key and value data from node
+ * to the variables at the location of oldkey and oldvalue (if specified), so
+ * they can be freed afterwards (if necessary).
+ * 
+ * Note: the returned key in oldkey is possibly not the same as the provided
+ * key for the lookup (in terms of memory location).
+ * 
+ * @param tree the UcxAVLTree
+ * @param key the key of the element to remove
+ * @param oldkey optional: a pointer to the location where the old key shall be
+ * stored
+ * @param oldvalue optional: a pointer to the location where the old value
+ * shall be stored
+ * @return zero, if and only if an element has been removed
+ */
+int ucx_avl_remove_s(UcxAVLTree *tree, intptr_t key,
+        intptr_t *oldkey, void **oldvalue);
+
+/**
+ * Counts the nodes in the specified UcxAVLTree.
+ * @param tree the AVL tree
+ * @return the node count
+ */
+size_t ucx_avl_count(UcxAVLTree *tree);
+
+/**
+ * Finds the in-order predecessor of the given node.
+ * @param node an AVL node
+ * @return the in-order predecessor of the given node, or <code>NULL</code> if
+ * the given node is the in-order minimum
+ */
+UcxAVLNode* ucx_avl_pred(UcxAVLNode* node);
+
+/**
+ * Finds the in-order successor of the given node.
+ * @param node an AVL node
+ * @return the in-order successor of the given node, or <code>NULL</code> if
+ * the given node is the in-order maximum
+ */
+UcxAVLNode* ucx_avl_succ(UcxAVLNode* node);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* UCX_AVL_H */
+