Make sure the enumerator stops after all items have been enumerated.
[strongswan.git] / src / libstrongswan / utils / linked_list.h
1 /*
2 * Copyright (C) 2007-2011 Tobias Brunner
3 * Copyright (C) 2005-2008 Martin Willi
4 * Copyright (C) 2005 Jan Hutter
5 * Hochschule fuer Technik Rapperswil
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * for more details.
16 */
17
18 /**
19 * @defgroup linked_list linked_list
20 * @{ @ingroup utils
21 */
22
23 #ifndef LINKED_LIST_H_
24 #define LINKED_LIST_H_
25
26 typedef struct linked_list_t linked_list_t;
27
28 #include <utils/enumerator.h>
29
30 /**
31 * Method to match elements in a linked list (used in find_* functions)
32 *
33 * @param item current list item
34 * @param ... user supplied data (only pointers, at most 5)
35 * @return
36 * - TRUE, if the item matched
37 * - FALSE, otherwise
38 */
39 typedef bool (*linked_list_match_t)(void *item, ...);
40
41 /**
42 * Method to be invoked on elements in a linked list (used in invoke_* functions)
43 *
44 * @param item current list item
45 * @param ... user supplied data (only pointers, at most 5)
46 */
47 typedef void (*linked_list_invoke_t)(void *item, ...);
48
49 /**
50 * Class implementing a double linked list.
51 *
52 * General purpose linked list. This list is not synchronized.
53 */
54 struct linked_list_t {
55
56 /**
57 * Gets the count of items in the list.
58 *
59 * @return number of items in list
60 */
61 int (*get_count) (linked_list_t *this);
62
63 /**
64 * Create an enumerator over the list.
65 *
66 * @note The enumerator's position is invalid before the first call
67 * to enumerate().
68 *
69 * @return enumerator over list items
70 */
71 enumerator_t* (*create_enumerator)(linked_list_t *this);
72
73 /**
74 * Resets the enumerator's current position to the beginning of the list.
75 *
76 * @param enumerator enumerator to reset
77 */
78 void (*reset_enumerator)(linked_list_t *this, enumerator_t *enumerator);
79
80 /**
81 * Inserts a new item at the beginning of the list.
82 *
83 * @param item item value to insert in list
84 */
85 void (*insert_first) (linked_list_t *this, void *item);
86
87 /**
88 * Removes the first item in the list and returns its value.
89 *
90 * @param item returned value of first item, or NULL
91 * @return SUCCESS, or NOT_FOUND if list is empty
92 */
93 status_t (*remove_first) (linked_list_t *this, void **item);
94
95 /**
96 * Inserts a new item before the item the enumerator currently points to.
97 *
98 * If this method is called before starting the enumeration the item is
99 * inserted first. If it is called after all items have been enumerated
100 * the item is inserted last. This is helpful when inserting items into
101 * a sorted list.
102 *
103 * @note The position of the enumerator is not changed.
104 *
105 * @param enumerator enumerator with position
106 * @param item item value to insert in list
107 */
108 void (*insert_before)(linked_list_t *this, enumerator_t *enumerator,
109 void *item);
110
111 /**
112 * Replaces the item the enumerator currently points to with the given item.
113 *
114 * @param enumerator enumerator with position
115 * @param item item value to replace current item with
116 * @return current item or NULL if the enumerator is at an
117 * invalid position
118 */
119 void *(*replace)(linked_list_t *this, enumerator_t *enumerator, void *item);
120
121 /**
122 * Remove an item from the list where the enumerator points to.
123 *
124 * @param enumerator enumerator with position
125 */
126 void (*remove_at)(linked_list_t *this, enumerator_t *enumerator);
127
128 /**
129 * Remove items from the list matching the given item.
130 *
131 * If a compare function is given, it is called for each item, with the
132 * first parameter being the current list item and the second parameter
133 * being the supplied item. Return TRUE from the compare function to remove
134 * the item, return FALSE to keep it in the list.
135 *
136 * If compare is NULL, comparison is done by pointers.
137 *
138 * @param item item to remove/pass to comparator
139 * @param compare compare function, or NULL
140 * @return number of removed items
141 */
142 int (*remove)(linked_list_t *this, void *item, bool (*compare)(void*,void*));
143
144 /**
145 * Returns the value of the first list item without removing it.
146 *
147 * @param item returned value of first item
148 * @return SUCCESS, NOT_FOUND if list is empty
149 */
150 status_t (*get_first) (linked_list_t *this, void **item);
151
152 /**
153 * Inserts a new item at the end of the list.
154 *
155 * @param item value to insert into list
156 */
157 void (*insert_last) (linked_list_t *this, void *item);
158
159 /**
160 * Removes the last item in the list and returns its value.
161 *
162 * @param item returned value of last item, or NULL
163 * @return SUCCESS, NOT_FOUND if list is empty
164 */
165 status_t (*remove_last) (linked_list_t *this, void **item);
166
167 /**
168 * Returns the value of the last list item without removing it.
169 *
170 * @param item returned value of last item
171 * @return SUCCESS, NOT_FOUND if list is empty
172 */
173 status_t (*get_last) (linked_list_t *this, void **item);
174
175 /** Find the first matching element in the list.
176 *
177 * The first object passed to the match function is the current list item,
178 * followed by the user supplied data.
179 * If the supplied function returns TRUE this function returns SUCCESS, and
180 * the current object is returned in the third parameter, otherwise,
181 * the next item is checked.
182 *
183 * If match is NULL, *item and the current object are compared.
184 *
185 * @warning Only use pointers as user supplied data.
186 *
187 * @param match comparison function to call on each object, or NULL
188 * @param item the list item, if found
189 * @param ... user data to supply to match function (limited to 5 arguments)
190 * @return SUCCESS if found, NOT_FOUND otherwise
191 */
192 status_t (*find_first) (linked_list_t *this, linked_list_match_t match,
193 void **item, ...);
194
195 /** Find the last matching element in the list.
196 *
197 * The first object passed to the match function is the current list item,
198 * followed by the user supplied data.
199 * If the supplied function returns TRUE this function returns SUCCESS, and
200 * the current object is returned in the third parameter, otherwise,
201 * the next item is checked.
202 *
203 * If match is NULL, *item and the current object are compared.
204 *
205 * @warning Only use pointers as user supplied data.
206 *
207 * @param match comparison function to call on each object, or NULL
208 * @param item the list item, if found
209 * @param ... user data to supply to match function (limited to 5 arguments)
210 * @return SUCCESS if found, NOT_FOUND otherwise
211 */
212 status_t (*find_last) (linked_list_t *this, linked_list_match_t match,
213 void **item, ...);
214
215 /**
216 * Invoke a method on all of the contained objects.
217 *
218 * If a linked list contains objects with function pointers,
219 * invoke() can call a method on each of the objects. The
220 * method is specified by an offset of the function pointer,
221 * which can be evalutated at compile time using the offsetof
222 * macro, e.g.: list->invoke(list, offsetof(object_t, method));
223 *
224 * @warning Only use pointers as user supplied data.
225 *
226 * @param offset offset of the method to invoke on objects
227 * @param ... user data to supply to called function (limited to 5 arguments)
228 */
229 void (*invoke_offset) (linked_list_t *this, size_t offset, ...);
230
231 /**
232 * Invoke a function on all of the contained objects.
233 *
234 * @warning Only use pointers as user supplied data.
235 *
236 * @param function offset of the method to invoke on objects
237 * @param ... user data to supply to called function (limited to 5 arguments)
238 */
239 void (*invoke_function) (linked_list_t *this, linked_list_invoke_t function, ...);
240
241 /**
242 * Clones a list and its objects using the objects' clone method.
243 *
244 * @param offset offset ot the objects clone function
245 * @return cloned list
246 */
247 linked_list_t *(*clone_offset) (linked_list_t *this, size_t offset);
248
249 /**
250 * Clones a list and its objects using a given function.
251 *
252 * @param function function that clones an object
253 * @return cloned list
254 */
255 linked_list_t *(*clone_function) (linked_list_t *this, void*(*)(void*));
256
257 /**
258 * Destroys a linked_list object.
259 */
260 void (*destroy) (linked_list_t *this);
261
262 /**
263 * Destroys a list and its objects using the destructor.
264 *
265 * If a linked list and the contained objects should be destroyed, use
266 * destroy_offset. The supplied offset specifies the destructor to
267 * call on each object. The offset may be calculated using the offsetof
268 * macro, e.g.: list->destroy_offset(list, offsetof(object_t, destroy));
269 *
270 * @param offset offset of the objects destructor
271 */
272 void (*destroy_offset) (linked_list_t *this, size_t offset);
273
274 /**
275 * Destroys a list and its contents using a a cleanup function.
276 *
277 * If a linked list and its contents should get destroyed using a specific
278 * cleanup function, use destroy_function. This is useful when the
279 * list contains malloc()-ed blocks which should get freed,
280 * e.g.: list->destroy_function(list, free);
281 *
282 * @param function function to call on each object
283 */
284 void (*destroy_function) (linked_list_t *this, void (*)(void*));
285 };
286
287 /**
288 * Creates an empty linked list object.
289 *
290 * @return linked_list_t object.
291 */
292 linked_list_t *linked_list_create(void);
293
294 #endif /** LINKED_LIST_H_ @}*/