+/**
+ * collectd - src/utils_avltree.h
+ * Copyright (C) 2006,2007 Florian octo Forster
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Authors:
+ * Florian octo Forster <octo at verplant.org>
+ **/
+
#ifndef UTILS_AVLTREE_H
#define UTILS_AVLTREE_H 1
-struct avl_tree_s;
-typedef struct avl_tree_s avl_tree_t;
+struct c_avl_tree_s;
+typedef struct c_avl_tree_s c_avl_tree_t;
+
+struct c_avl_iterator_s;
+typedef struct c_avl_iterator_s c_avl_iterator_t;
+
+/*
+ * NAME
+ * c_avl_create
+ *
+ * DESCRIPTION
+ * Allocates a new AVL-tree.
+ *
+ * PARAMETERS
+ * `compare' The function-pointer `compare' is used to compare two keys. It
+ * has to return less than zero if it's first argument is smaller
+ * then the second argument, more than zero if the first argument
+ * is bigger than the second argument and zero if they are equal.
+ * If your keys are char-pointers, you can use the `strcmp'
+ * function from the libc here.
+ *
+ * RETURN VALUE
+ * A c_avl_tree_t-pointer upon success or NULL upon failure.
+ */
+c_avl_tree_t *c_avl_create (int (*compare) (const void *, const void *));
+
-struct avl_iterator_s;
-typedef struct avl_iterator_s avl_iterator_t;
+/*
+ * NAME
+ * c_avl_destroy
+ *
+ * DESCRIPTION
+ * Deallocates an AVL-tree. Stored value- and key-pointer are lost, but of
+ * course not freed.
+ */
+void c_avl_destroy (c_avl_tree_t *t);
-struct avl_keyval_s
-{
- void *key;
- void *value;
-};
+/*
+ * NAME
+ * c_avl_insert
+ *
+ * DESCRIPTION
+ * Stores the key-value-pair in the AVL-tree pointed to by `t'.
+ *
+ * PARAMETERS
+ * `t' AVL-tree to store the data in.
+ * `key' Key used to store the value under. This is used to get back to
+ * the value again. The pointer is stored in an internal structure
+ * and _not_ copied. So the memory pointed to may _not_ be freed
+ * before this entry is removed. You can use the `rkey' argument
+ * to `avl_remove' to get the original pointer back and free it.
+ * `value' Value to be stored.
+ *
+ * RETURN VALUE
+ * Zero upon success, non-zero otherwise. It's less than zero if an error
+ * occurred or greater than zero if the key is already stored in the tree.
+ */
+int c_avl_insert (c_avl_tree_t *t, void *key, void *value);
-avl_tree_t *avl_create (int (*compare) (const void *, const void *));
-void avl_destroy (avl_tree_t *t);
+/*
+ * NAME
+ * c_avl_remove
+ *
+ * DESCRIPTION
+ * Removes a key-value-pair from the tree t. The stored key and value may be
+ * returned in `rkey' and `rvalue'.
+ *
+ * PARAMETERS
+ * `t' AVL-tree to remove key-value-pair from.
+ * `key' Key to identify the entry.
+ * `rkey' Pointer to a pointer in which to store the key. May be NULL.
+ * Since the `key' pointer is not copied when creating an entry,
+ * the pointer may not be available anymore from outside the tree.
+ * You can use this argument to get the actual pointer back and
+ * free the memory pointed to by it.
+ * `rvalue' Pointer to a pointer in which to store the value. May be NULL.
+ *
+ * RETURN VALUE
+ * Zero upon success or non-zero if the key isn't found in the tree.
+ */
+int c_avl_remove (c_avl_tree_t *t, const void *key, void **rkey, void **rvalue);
-int avl_insert (avl_tree_t *t, void *key, void *value);
-int avl_remove (avl_tree_t *t, void *key, void **rkey, void **rvalue);
+/*
+ * NAME
+ * c_avl_get
+ *
+ * DESCRIPTION
+ * Retrieve the `value' belonging to `key'.
+ *
+ * PARAMETERS
+ * `t' AVL-tree to get the value from.
+ * `key' Key to identify the entry.
+ * `value' Pointer to a pointer in which to store the value. May be NULL.
+ *
+ * RETURN VALUE
+ * Zero upon success or non-zero if the key isn't found in the tree.
+ */
+int c_avl_get (c_avl_tree_t *t, const void *key, void **value);
-int avl_get (avl_tree_t *t, const void *key, void **value);
+/*
+ * NAME
+ * c_avl_pick
+ *
+ * DESCRIPTION
+ * Remove a (pseudo-)random element from the tree and return it's `key' and
+ * `value'. Entries are not returned in any particular order. This function
+ * is intended for cache-flushes that don't care about the order but simply
+ * want to remove all elements, one at a time.
+ *
+ * PARAMETERS
+ * `t' AVL-tree to get the value from.
+ * `key' Pointer to a pointer in which to store the key.
+ * `value' Pointer to a pointer in which to store the value.
+ *
+ * RETURN VALUE
+ * Zero upon success or non-zero if the tree is empty or key or value is
+ * NULL.
+ */
+int c_avl_pick (c_avl_tree_t *t, void **key, void **value);
-avl_iterator_t *avl_get_iterator (avl_tree_t *t);
-void *avl_iterator_next (avl_iterator_t *iter);
-void *avl_iterator_prev (avl_iterator_t *iter);
-void avl_iterator_destroy (avl_iterator_t *iter);
+c_avl_iterator_t *c_avl_get_iterator (c_avl_tree_t *t);
+int c_avl_iterator_next (c_avl_iterator_t *iter, void **key, void **value);
+int c_avl_iterator_prev (c_avl_iterator_t *iter, void **key, void **value);
+void c_avl_iterator_destroy (c_avl_iterator_t *iter);
#endif /* UTILS_AVLTREE_H */
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