1 /*
2 * SysDB - src/include/utils/llist.h
3 * Copyright (C) 2012 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_LLIST_H
29 #define SDB_UTILS_LLIST_H 1
31 #include "core/object.h"
33 #include <stdbool.h>
35 #ifdef __cplusplus
36 extern "C" {
37 #endif
39 struct sdb_llist;
40 typedef struct sdb_llist sdb_llist_t;
42 struct sdb_llist_iter;
43 typedef struct sdb_llist_iter sdb_llist_iter_t;
45 /*
46 * sdb_llist_create, sdb_llist_destroy:
47 * Create and destroy a doubly linked list object.
48 *
49 * sdb_llist_create returns NULL on error.
50 * sdb_llist_destroy will also destroy all remaining elements, thus releasing
51 * the included objects (decrement the ref-count).
52 */
53 sdb_llist_t *
54 sdb_llist_create(void);
55 void
56 sdb_llist_destroy(sdb_llist_t *list);
58 /*
59 * sdb_llist_clear:
60 * Remove all elements from the list, releasing the included objects
61 * (decrement the ref-count).
62 */
63 void
64 sdb_llist_clear(sdb_llist_t *list);
66 /*
67 * sdb_llist_clone:
68 * Clone an existing list. The objects stored in the list will not be copied
69 * but rather their reference count incremented.
70 *
71 * Returns:
72 * - the copied list on success
73 * - NULL else
74 */
75 sdb_llist_t *
76 sdb_llist_clone(sdb_llist_t *list);
78 /*
79 * sdb_llist_append:
80 * Append the given 'obj' to the end of 'list'. The list will take ownership
81 * of the object, that is, increment the reference count by one. In case the
82 * caller does not longer use the object for other purposes, it should thus
83 * deref it.
84 *
85 * Returns:
86 * - 0 on success
87 * - a negative value on failure
88 */
89 int
90 sdb_llist_append(sdb_llist_t *list, sdb_object_t *obj);
92 /*
93 * sdb_llist_insert:
94 * Insert the new element at the specified position (zero being the head of
95 * the list; the length of the list being the tail)). If the index is greater
96 * than the length of the list (i.e. past the tail of the list), an error is
97 * returned. The list will take ownership of the object, that is, increment
98 * the reference count by one. In case the caller does not longer use the
99 * object for other purposes, it should thus deref it.
100 *
101 * Returns:
102 * - 0 on success
103 * - a negative value on failure
104 */
105 int
106 sdb_llist_insert(sdb_llist_t *list, sdb_object_t *obj, size_t idx);
108 /*
109 * sdb_llist_insert_sorted:
110 * Insert the given 'obj' in the 'list' using a sort order as determined by
111 * the 'compare' function. The function will insert the new entry before the
112 * first entry which sorts later than the new entry. It will not ensure that
113 * the rest of the list is sorted. The list will take ownership of the object,
114 * that is, increment the reference count by one. In case the caller does not
115 * longer use the object for other purposes, it should thus deref it.
116 *
117 * The 'compare' function should return less than zero, zero, greater than
118 * zero if the first argument sorts less than, equal or greater than the
119 * second argument respectively.
120 *
121 * Returns:
122 * - 0 on success
123 * - a negative value on failure
124 */
125 int
126 sdb_llist_insert_sorted(sdb_llist_t *list,
127 sdb_object_t *obj, sdb_object_cmp_cb);
129 /*
130 * sdb_llist_get:
131 * Returns the i-th element of the list or NULL in case of an error. The
132 * reference count of the element is incremented before returning it to share
133 * ownership between the list and the caller.
134 */
135 sdb_object_t *
136 sdb_llist_get(sdb_llist_t *list, size_t i);
138 /*
139 * sdb_llist_search:
140 * Search for a object in the given 'list'. The function will return the first
141 * entry for which the 'lookup' callback returns 0. The 'user_data' is passed
142 * on to the lookup function on each invocation.
143 *
144 * Returns:
145 * - a pointer to the first matching object
146 * - NULL else
147 */
148 sdb_object_t *
149 sdb_llist_search(sdb_llist_t *list,
150 sdb_object_lookup_cb lookup, const void *user_data);
152 /*
153 * sdb_llist_search_by_name:
154 * Search for an object named 'key' in the given 'list'. The function will
155 * return the first entry whose name matches the specified 'key' ignoring the
156 * case of the characters.
157 *
158 * Returns:
159 * - a pointer to the first matching object
160 * - NULL else
161 */
162 sdb_object_t *
163 sdb_llist_search_by_name(sdb_llist_t *list, const char *key);
165 /*
166 * sdb_llist_remove:
167 * Removes and returns the first matching element of the list. The ref-count
168 * of the item will not be changed, that is, if the element will not be used
169 * any further, it should be de-referenced by the caller.
170 *
171 * Returns:
172 * - a pointer to the first matching object
173 * - NULL else
174 */
175 sdb_object_t *
176 sdb_llist_remove(sdb_llist_t *list,
177 sdb_object_lookup_cb lookup, const void *user_data);
179 /*
180 * sdb_llist_remove_by_name:
181 * Removes and returns the first element whose name matches the specified key.
182 * The ref-count of the item will not be changed, that is, if the element will
183 * not be used any further, it should be de-referenced by the caller.
184 *
185 * Returns:
186 * - a pointer to the first matching object
187 * - NULL else
188 */
189 sdb_object_t *
190 sdb_llist_remove_by_name(sdb_llist_t *list, const char *key);
192 /*
193 * sdb_llist_shift:
194 * Removes and returns the first element of the list. The ref-count of the
195 * item will not be changed, that is, if the element will not be used any
196 * further, it should be de-referenced by the caller.
197 *
198 * Returns:
199 * - the former first element of the list
200 * - NULL if the list is empty
201 */
202 sdb_object_t *
203 sdb_llist_shift(sdb_llist_t *list);
205 /*
206 * sdb_llist_get_iter, sdb_llist_iter_has_next, sdb_llist_iter_get_next:
207 * Iterate through the list, element by element.
208 *
209 * sdb_llist_iter_get_next returns NULL if there is no next element.
210 */
211 sdb_llist_iter_t *
212 sdb_llist_get_iter(sdb_llist_t *list);
213 void
214 sdb_llist_iter_destroy(sdb_llist_iter_t *iter);
216 bool
217 sdb_llist_iter_has_next(sdb_llist_iter_t *iter);
218 sdb_object_t *
219 sdb_llist_iter_get_next(sdb_llist_iter_t *iter);
221 /*
222 * sdb_llist_iter_remove_current:
223 * Remove the current object from the list, that is, the object which was
224 * returned by the last call to sdb_llist_iter_get_next().
225 *
226 * This operation is not safe if another iterator is in use at the same time.
227 *
228 * Returns:
229 * - 0 on success
230 * - a negative value else
231 */
232 int
233 sdb_llist_iter_remove_current(sdb_llist_iter_t *iter);
235 /*
236 * sdb_llist_len:
237 * Return the length (number of elements) of the list.
238 */
239 size_t
240 sdb_llist_len(sdb_llist_t *list);
242 #ifdef __cplusplus
243 } /* extern "C" */
244 #endif
246 #endif /* ! SDB_UTILS_LLIST_H */
248 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */