ba495c665ff6e884c2e6d6efdf308b5fc3c1ec79
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 #include <stdbool.h>
35 #ifdef __cplusplus
36 extern "C" {
37 #endif
39 /*
40 * An AVL tree implements Adelson-Velskii and Landis' self-balancing search
41 * tree. It supports search, insert, and delete operations in average and
42 * worst-case time-complexity O(log n).
43 */
44 struct sdb_avltree;
45 typedef struct sdb_avltree sdb_avltree_t;
47 struct sdb_avltree_iter;
48 typedef struct sdb_avltree_iter sdb_avltree_iter_t;
50 /*
51 * sdb_avltree_create:
52 * Creates an AVL tree. Objects will be compared by their names.
53 */
54 sdb_avltree_t *
55 sdb_avltree_create(void);
57 /*
58 * sdb_avltree_destroy:
59 * Destroy the specified AVL tree and release all included objects (decrement
60 * the ref-count).
61 */
62 void
63 sdb_avltree_destroy(sdb_avltree_t *tree);
65 /*
66 * sdb_avltree_clear:
67 * Remove all nodes from the tree, releasing the included objects (decrement
68 * the ref-count).
69 */
70 void
71 sdb_avltree_clear(sdb_avltree_t *tree);
73 /*
74 * sdb_avltree_insert:
75 * Insert a new node into the tree. Each object must be unique. This operation
76 * may change the structure of the tree by rebalancing subtrees which no
77 * longer comply with the rules of AVL.
78 *
79 * Returns:
80 * - 0 on success
81 * - a negative value else
82 */
83 int
84 sdb_avltree_insert(sdb_avltree_t *tree, sdb_object_t *obj);
86 /*
87 * sdb_avltree_lookup:
88 * Lookup an object from a tree by name.
89 *
90 * Returns:
91 * - the requested object
92 * - NULL if no such object exists
93 */
94 sdb_object_t *
95 sdb_avltree_lookup(sdb_avltree_t *tree, const char *name);
97 /*
98 * sdb_avltree_get_iter, sdb_avltree_iter_has_next, sdb_avltree_iter_get_next,
99 * sdb_avltree_iter_destroy:
100 * Iterate through all nodes of the tree. The iterator will start at the
101 * smallest element (based on the name) and then iterate through the sorted
102 * sequence of all nodes.
103 *
104 * sdb_avltree_iter_get_next returns NULL if there is no next element.
105 */
106 sdb_avltree_iter_t *
107 sdb_avltree_get_iter(sdb_avltree_t *tree);
108 void
109 sdb_avltree_iter_destroy(sdb_avltree_iter_t *iter);
111 bool
112 sdb_avltree_iter_has_next(sdb_avltree_iter_t *iter);
113 sdb_object_t *
114 sdb_avltree_iter_get_next(sdb_avltree_iter_t *iter);
116 /*
117 * sdb_avltree_iter_peek_next:
118 * Peek at the next node, if there is one. This is similar to has_next() but
119 * it returns the actual next element without advancing the iterator.
120 *
121 * Returns:
122 * - the next node, if there is one
123 * - NULL else
124 */
125 sdb_object_t *
126 sdb_avltree_iter_peek_next(sdb_avltree_iter_t *iter);
128 /*
129 * sdb_avltree_size:
130 * Returns the number of nodes in the tree.
131 */
132 size_t
133 sdb_avltree_size(sdb_avltree_t *tree);
135 /*
136 * sdb_avltree_valid:
137 * Validate a tree, checking if all rules of AVL are met. All errors will be
138 * reported through the logging sub-system. This function is mainly intended
139 * for debugging and (unit) testing.
140 *
141 * Returns:
142 * - true if the tree is valid
143 * - false else
144 */
145 bool
146 sdb_avltree_valid(sdb_avltree_t *tree);
148 #ifdef __cplusplus
149 } /* extern "C" */
150 #endif
152 #endif /* ! SDB_UTILS_AVLTREE_H */
154 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */