1 /**
2 * collectd - src/utils_avltree.h
3 * Copyright (C) 2006,2007 Florian octo Forster
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors:
20 * Florian octo Forster <octo at verplant.org>
21 **/
23 #ifndef UTILS_AVLTREE_H
24 #define UTILS_AVLTREE_H 1
26 struct c_avl_tree_s;
27 typedef struct c_avl_tree_s c_avl_tree_t;
29 struct c_avl_iterator_s;
30 typedef struct c_avl_iterator_s c_avl_iterator_t;
32 /*
33 * NAME
34 * c_avl_create
35 *
36 * DESCRIPTION
37 * Allocates a new AVL-tree.
38 *
39 * PARAMETERS
40 * `compare' The function-pointer `compare' is used to compare two keys. It
41 * has to return less than zero if it's first argument is smaller
42 * then the second argument, more than zero if the first argument
43 * is bigger than the second argument and zero if they are equal.
44 * If your keys are char-pointers, you can use the `strcmp'
45 * function from the libc here.
46 *
47 * RETURN VALUE
48 * A c_avl_tree_t-pointer upon success or NULL upon failure.
49 */
50 c_avl_tree_t *c_avl_create (int (*compare) (const void *, const void *));
53 /*
54 * NAME
55 * c_avl_destroy
56 *
57 * DESCRIPTION
58 * Deallocates an AVL-tree. Stored value- and key-pointer are lost, but of
59 * course not freed.
60 */
61 void c_avl_destroy (c_avl_tree_t *t);
63 /*
64 * NAME
65 * c_avl_insert
66 *
67 * DESCRIPTION
68 * Stores the key-value-pair in the AVL-tree pointed to by `t'.
69 *
70 * PARAMETERS
71 * `t' AVL-tree to store the data in.
72 * `key' Key used to store the value under. This is used to get back to
73 * the value again. The pointer is stored in an internal structure
74 * and _not_ copied. So the memory pointed to may _not_ be freed
75 * before this entry is removed. You can use the `rkey' argument
76 * to `avl_remove' to get the original pointer back and free it.
77 * `value' Value to be stored.
78 *
79 * RETURN VALUE
80 * Zero upon success, non-zero otherwise. It's less than zero if an error
81 * occurred or greater than zero if the key is already stored in the tree.
82 */
83 int c_avl_insert (c_avl_tree_t *t, void *key, void *value);
85 /*
86 * NAME
87 * c_avl_remove
88 *
89 * DESCRIPTION
90 * Removes a key-value-pair from the tree t. The stored key and value may be
91 * returned in `rkey' and `rvalue'.
92 *
93 * PARAMETERS
94 * `t' AVL-tree to remove key-value-pair from.
95 * `key' Key to identify the entry.
96 * `rkey' Pointer to a pointer in which to store the key. May be NULL.
97 * Since the `key' pointer is not copied when creating an entry,
98 * the pointer may not be available anymore from outside the tree.
99 * You can use this argument to get the actual pointer back and
100 * free the memory pointed to by it.
101 * `rvalue' Pointer to a pointer in which to store the value. May be NULL.
102 *
103 * RETURN VALUE
104 * Zero upon success or non-zero if the key isn't found in the tree.
105 */
106 int c_avl_remove (c_avl_tree_t *t, const void *key, void **rkey, void **rvalue);
108 /*
109 * NAME
110 * c_avl_get
111 *
112 * DESCRIPTION
113 * Retrieve the `value' belonging to `key'.
114 *
115 * PARAMETERS
116 * `t' AVL-tree to get the value from.
117 * `key' Key to identify the entry.
118 * `value' Pointer to a pointer in which to store the value. May be NULL.
119 *
120 * RETURN VALUE
121 * Zero upon success or non-zero if the key isn't found in the tree.
122 */
123 int c_avl_get (c_avl_tree_t *t, const void *key, void **value);
125 /*
126 * NAME
127 * c_avl_pick
128 *
129 * DESCRIPTION
130 * Remove a (pseudo-)random element from the tree and return it's `key' and
131 * `value'. Entries are not returned in any particular order. This function
132 * is intended for cache-flushes that don't care about the order but simply
133 * want to remove all elements, one at a time.
134 *
135 * PARAMETERS
136 * `t' AVL-tree to get the value from.
137 * `key' Pointer to a pointer in which to store the key.
138 * `value' Pointer to a pointer in which to store the value.
139 *
140 * RETURN VALUE
141 * Zero upon success or non-zero if the tree is empty or key or value is
142 * NULL.
143 */
144 int c_avl_pick (c_avl_tree_t *t, void **key, void **value);
146 c_avl_iterator_t *c_avl_get_iterator (c_avl_tree_t *t);
147 int c_avl_iterator_next (c_avl_iterator_t *iter, void **key, void **value);
148 int c_avl_iterator_prev (c_avl_iterator_t *iter, void **key, void **value);
149 void c_avl_iterator_destroy (c_avl_iterator_t *iter);
151 #endif /* UTILS_AVLTREE_H */