1 /*
2 * SysDB - src/include/utils/avltree.h
3 * Copyright (C) 2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
4 * 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
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #ifndef SDB_UTILS_AVLTREE_H
29 #define SDB_UTILS_AVLTREE_H 1
31 #include "core/object.h"
33 #ifdef __cplusplus
34 extern "C" {
35 #endif
37 /*
38 * An AVL tree implements Adelson-Velskii and Landis' self-balancing search
39 * tree. It supports search, insert, and delete operations in average and
40 * worst-case time-complexity O(log n).
41 */
42 struct sdb_avltree;
43 typedef struct sdb_avltree sdb_avltree_t;
45 struct sdb_avltree_iter;
46 typedef struct sdb_avltree_iter sdb_avltree_iter_t;
48 /*
49 * sdb_avltree_create:
50 * Creates an AVL tree. Insert and lookup operations will use the specified
51 * compare function to determine the location of an object in the tree. If no
52 * function has been specified, it defaults to sdb_object_cmp_by_name, that
53 * is, objects will be compared by their names.
54 */
55 sdb_avltree_t *
56 sdb_avltree_create(sdb_object_cmp_cb cmp);
58 /*
59 * sdb_avltree_destroy:
60 * Destroy the specified AVL tree and release all included objects (decrement
61 * the ref-count).
62 */
63 void
64 sdb_avltree_destroy(sdb_avltree_t *tree);
66 /*
67 * sdb_avltree_clear:
68 * Remove all nodes from the tree, releasing the included objects (decrement
69 * the ref-count).
70 */
71 void
72 sdb_avltree_clear(sdb_avltree_t *tree);
74 /*
75 * sdb_avltree_insert:
76 * Insert a new node into the tree (using the tree's compare function to find
77 * the right location). Each object must be unique (based on the compare
78 * function). This operation may change the structure of the tree by
79 * rebalancing subtrees which no longer comply with the rules of AVL.
80 *
81 * Returns:
82 * - 0 on success
83 * - a negative value else
84 */
85 int
86 sdb_avltree_insert(sdb_avltree_t *tree, sdb_object_t *obj);
88 /*
89 * sdb_avltree_lookup:
90 * Lookup an object from a tree. The object matching the specified reference
91 * object (using the tree's compare function) will be returned.
92 *
93 * Returns:
94 * - the requested object
95 * - NULL if no such object exists
96 */
97 sdb_object_t *
98 sdb_avltree_lookup(sdb_avltree_t *tree, const sdb_object_t *ref);
100 /*
101 * sdb_avltree_get_iter, sdb_avltree_iter_has_next, sdb_avltree_iter_get_next,
102 * sdb_avltree_iter_destroy:
103 * Iterate through all nodes of the tree. The iterator will start at the
104 * smallest element (based on the tree's compare function) and then iterate
105 * through the sorted sequence of all nodes.
106 *
107 * sdb_avltree_iter_get_next returns NULL if there is no next element.
108 */
109 sdb_avltree_iter_t *
110 sdb_avltree_get_iter(sdb_avltree_t *tree);
111 void
112 sdb_avltree_iter_destroy(sdb_avltree_iter_t *iter);
114 _Bool
115 sdb_avltree_iter_has_next(sdb_avltree_iter_t *iter);
116 sdb_object_t *
117 sdb_avltree_iter_get_next(sdb_avltree_iter_t *iter);
119 /*
120 * sdb_avltree_size:
121 * Returns the number of nodes in the tree.
122 */
123 size_t
124 sdb_avltree_size(sdb_avltree_t *tree);
126 /*
127 * sdb_avltree_valid:
128 * Validate a tree, checking if all rules of AVL are met. All errors will be
129 * reported through the logging sub-system. This function is mainly intended
130 * for debugging and (unit) testing.
131 *
132 * Returns:
133 * - true if the tree is valid
134 * - false else
135 */
136 _Bool
137 sdb_avltree_valid(sdb_avltree_t *tree);
139 #ifdef __cplusplus
140 } /* extern "C" */
141 #endif
143 #endif /* ! SDB_UTILS_AVLTREE_H */
145 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */