2 This file is part of systemd.
4 Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
25 #include "libudev-private.h"
28 * SECTION:libudev-list
29 * @short_description: list operation
31 * Libudev list operations.
37 * Opaque object representing one entry in a list. An entry contains
38 * contains a name, and optionally a value.
40 struct udev_list_entry {
41 struct udev_list_node node;
42 struct udev_list *list;
48 /* the list's head points to itself if empty */
49 void udev_list_node_init(struct udev_list_node *list)
55 int udev_list_node_is_empty(struct udev_list_node *list)
57 return list->next == list;
60 static void udev_list_node_insert_between(struct udev_list_node *new,
61 struct udev_list_node *prev,
62 struct udev_list_node *next)
70 void udev_list_node_append(struct udev_list_node *new, struct udev_list_node *list)
72 udev_list_node_insert_between(new, list->prev, list);
75 void udev_list_node_remove(struct udev_list_node *entry)
77 struct udev_list_node *prev = entry->prev;
78 struct udev_list_node *next = entry->next;
87 /* return list entry which embeds this node */
88 static inline struct udev_list_entry *list_node_to_entry(struct udev_list_node *node)
90 return container_of(node, struct udev_list_entry, node);
93 void udev_list_init(struct udev *udev, struct udev_list *list, bool unique)
95 memzero(list, sizeof(struct udev_list));
97 list->unique = unique;
98 udev_list_node_init(&list->node);
101 /* insert entry into a list as the last element */
102 static void udev_list_entry_append(struct udev_list_entry *new, struct udev_list *list)
104 /* inserting before the list head make the node the last node in the list */
105 udev_list_node_insert_between(&new->node, list->node.prev, &list->node);
109 /* insert entry into a list, before a given existing entry */
110 static void udev_list_entry_insert_before(struct udev_list_entry *new, struct udev_list_entry *entry)
112 udev_list_node_insert_between(&new->node, entry->node.prev, &entry->node);
113 new->list = entry->list;
116 /* binary search in sorted array */
117 static int list_search(struct udev_list *list, const char *name)
119 unsigned int first, last;
122 last = list->entries_cur;
123 while (first < last) {
127 i = (first + last)/2;
128 cmp = strcmp(name, list->entries[i]->name);
137 /* not found, return negative insertion-index+1 */
141 struct udev_list_entry *udev_list_entry_add(struct udev_list *list, const char *name, const char *value)
143 struct udev_list_entry *entry;
147 /* lookup existing name or insertion-index */
148 i = list_search(list, name);
150 entry = list->entries[i];
157 entry->value = strdup(value);
158 if (entry->value == NULL)
165 entry = new0(struct udev_list_entry, 1);
168 entry->name = strdup(name);
169 if (entry->name == NULL) {
174 entry->value = strdup(value);
175 if (entry->value == NULL) {
183 /* allocate or enlarge sorted array if needed */
184 if (list->entries_cur >= list->entries_max) {
185 struct udev_list_entry **entries;
188 add = list->entries_max;
191 entries = realloc(list->entries, (list->entries_max + add) * sizeof(struct udev_list_entry *));
192 if (entries == NULL) {
198 list->entries = entries;
199 list->entries_max += add;
202 /* the negative i returned the insertion index */
205 /* insert into sorted list */
206 if ((unsigned int)i < list->entries_cur)
207 udev_list_entry_insert_before(entry, list->entries[i]);
209 udev_list_entry_append(entry, list);
211 /* insert into sorted array */
212 memmove(&list->entries[i+1], &list->entries[i],
213 (list->entries_cur - i) * sizeof(struct udev_list_entry *));
214 list->entries[i] = entry;
217 udev_list_entry_append(entry, list);
223 void udev_list_entry_delete(struct udev_list_entry *entry)
225 if (entry->list->entries != NULL) {
227 struct udev_list *list = entry->list;
229 /* remove entry from sorted array */
230 i = list_search(list, entry->name);
232 memmove(&list->entries[i], &list->entries[i+1],
233 ((list->entries_cur-1) - i) * sizeof(struct udev_list_entry *));
238 udev_list_node_remove(&entry->node);
244 void udev_list_cleanup(struct udev_list *list)
246 struct udev_list_entry *entry_loop;
247 struct udev_list_entry *entry_tmp;
250 list->entries = NULL;
251 list->entries_cur = 0;
252 list->entries_max = 0;
253 udev_list_entry_foreach_safe(entry_loop, entry_tmp, udev_list_get_entry(list))
254 udev_list_entry_delete(entry_loop);
257 struct udev_list_entry *udev_list_get_entry(struct udev_list *list)
259 if (udev_list_node_is_empty(&list->node))
261 return list_node_to_entry(list->node.next);
265 * udev_list_entry_get_next:
266 * @list_entry: current entry
268 * Get the next entry from the list.
270 * Returns: udev_list_entry, #NULL if no more entries are available.
272 _public_ struct udev_list_entry *udev_list_entry_get_next(struct udev_list_entry *list_entry)
274 struct udev_list_node *next;
276 if (list_entry == NULL)
278 next = list_entry->node.next;
279 /* empty list or no more entries */
280 if (next == &list_entry->list->node)
282 return list_node_to_entry(next);
286 * udev_list_entry_get_by_name:
287 * @list_entry: current entry
288 * @name: name string to match
290 * Lookup an entry in the list with a certain name.
292 * Returns: udev_list_entry, #NULL if no matching entry is found.
294 _public_ struct udev_list_entry *udev_list_entry_get_by_name(struct udev_list_entry *list_entry, const char *name)
298 if (list_entry == NULL)
301 if (!list_entry->list->unique)
304 i = list_search(list_entry->list, name);
307 return list_entry->list->entries[i];
311 * udev_list_entry_get_name:
312 * @list_entry: current entry
314 * Get the name of a list entry.
316 * Returns: the name string of this entry.
318 _public_ const char *udev_list_entry_get_name(struct udev_list_entry *list_entry)
320 if (list_entry == NULL)
322 return list_entry->name;
326 * udev_list_entry_get_value:
327 * @list_entry: current entry
329 * Get the value of list entry.
331 * Returns: the value string of this entry.
333 _public_ const char *udev_list_entry_get_value(struct udev_list_entry *list_entry)
335 if (list_entry == NULL)
337 return list_entry->value;
340 int udev_list_entry_get_num(struct udev_list_entry *list_entry)
342 if (list_entry == NULL)
344 return list_entry->num;
347 void udev_list_entry_set_num(struct udev_list_entry *list_entry, int num)
349 if (list_entry == NULL)
351 list_entry->num = num;