1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
19 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
20 * file for a list of people on the GLib Team. See the ChangeLog
21 * files for a list of changes. These files are distributed with
22 * GLib at ftp://ftp.gtk.org/pub/gtk/.
33 #include "gmessages.h"
35 #include "gtestutils.h"
38 * SECTION:linked_lists_double
39 * @title: Doubly-Linked Lists
40 * @short_description: linked lists that can be iterated over in both directions
42 * The #GList structure and its associated functions provide a standard
43 * doubly-linked list data structure.
45 * Each element in the list contains a piece of data, together with
46 * pointers which link to the previous and next elements in the list.
47 * Using these pointers it is possible to move through the list in both
48 * directions (unlike the singly-linked [GSList][glib-Singly-Linked-Lists],
49 * which only allows movement through the list in the forward direction).
51 * The double linked list does not keep track of the number of items
52 * and does not keep track of both the start and end of the list. If
53 * you want fast access to both the start and the end of the list,
54 * and/or the number of items in the list, use a
55 * [GQueue][glib-Double-ended-Queues] instead.
57 * The data contained in each element can be either integer values, by
58 * using one of the [Type Conversion Macros][glib-Type-Conversion-Macros],
59 * or simply pointers to any type of data.
61 * List elements are allocated from the [slice allocator][glib-Memory-Slices],
62 * which is more efficient than allocating elements individually.
64 * Note that most of the #GList functions expect to be passed a pointer
65 * to the first element in the list. The functions which insert
66 * elements return the new start of the list, which may have changed.
68 * There is no function to create a #GList. %NULL is considered to be
69 * a valid, empty list so you simply set a #GList* to %NULL to initialize
72 * To add elements, use g_list_append(), g_list_prepend(),
73 * g_list_insert() and g_list_insert_sorted().
75 * To visit all elements in the list, use a loop over the list:
76 * |[<!-- language="C" -->
78 * for (l = list; l != NULL; l = l->next)
80 * /* do something with l->data */
84 * To call a function for each element in the list, use g_list_foreach().
86 * To loop over the list and modify it (e.g. remove a certain element)
87 * a while loop is more appropriate, for example:
88 * |[<!-- language="C" -->
92 * GList *next = l->next;
93 * if (should_be_removed (l))
95 * /* possibly free l->data */
96 * list = g_list_delete_link (list, l);
102 * To remove elements, use g_list_remove().
104 * To navigate in a list, use g_list_first(), g_list_last(),
105 * g_list_next(), g_list_previous().
107 * To find elements in the list use g_list_nth(), g_list_nth_data(),
108 * g_list_find() and g_list_find_custom().
110 * To find the index of an element use g_list_position() and
113 * To free the entire list, use g_list_free() or g_list_free_full().
118 * @data: holds the element's data, which can be a pointer to any kind
119 * of data, or any integer value using the
120 * [Type Conversion Macros][glib-Type-Conversion-Macros]
121 * @next: contains the link to the next element in the list
122 * @prev: contains the link to the previous element in the list
124 * The #GList struct is used for each element in a doubly-linked list.
129 * @list: an element in a #GList
131 * A convenience macro to get the previous element in a #GList.
132 * Note that it is considered perfectly acceptable to access
133 * @list->previous directly.
135 * Returns: the previous element, or %NULL if there are no previous
141 * @list: an element in a #GList
143 * A convenience macro to get the next element in a #GList.
144 * Note that it is considered perfectly acceptable to access
145 * @list->next directly.
147 * Returns: the next element, or %NULL if there are no more elements
150 #define _g_list_alloc() g_slice_new (GList)
151 #define _g_list_alloc0() g_slice_new0 (GList)
152 #define _g_list_free1(list) g_slice_free (GList, list)
157 * Allocates space for one #GList element. It is called by
158 * g_list_append(), g_list_prepend(), g_list_insert() and
159 * g_list_insert_sorted() and so is rarely used on its own.
161 * Returns: a pointer to the newly-allocated #GList element
166 return _g_list_alloc0 ();
173 * Frees all of the memory used by a #GList.
174 * The freed elements are returned to the slice allocator.
176 * If list elements contain dynamically-allocated memory, you should
177 * either use g_list_free_full() or free them manually first.
180 g_list_free (GList *list)
182 g_slice_free_chain (GList, list, next);
187 * @list: a #GList element
189 * Frees one #GList element.
190 * It is usually used after g_list_remove_link().
195 * Another name for g_list_free_1().
198 g_list_free_1 (GList *list)
200 _g_list_free1 (list);
205 * @list: a pointer to a #GList
206 * @free_func: the function to be called to free each element's data
208 * Convenience method, which frees all the memory used by a #GList,
209 * and calls @free_func on every element's data.
214 g_list_free_full (GList *list,
215 GDestroyNotify free_func)
217 g_list_foreach (list, (GFunc) free_func, NULL);
223 * @list: a pointer to a #GList
224 * @data: the data for the new element
226 * Adds a new element on to the end of the list.
228 * Note that the return value is the new start of the list,
229 * if @list was empty; make sure you store the new value.
231 * g_list_append() has to traverse the entire list to find the end,
232 * which is inefficient when adding multiple elements. A common idiom
233 * to avoid the inefficiency is to use g_list_prepend() and reverse
234 * the list with g_list_reverse() when all elements have been added.
236 * |[<!-- language="C" -->
237 * /* Notice that these are initialized to the empty list. */
238 * GList *string_list = NULL, *number_list = NULL;
240 * /* This is a list of strings. */
241 * string_list = g_list_append (string_list, "first");
242 * string_list = g_list_append (string_list, "second");
244 * /* This is a list of integers. */
245 * number_list = g_list_append (number_list, GINT_TO_POINTER (27));
246 * number_list = g_list_append (number_list, GINT_TO_POINTER (14));
249 * Returns: either @list or the new start of the #GList if @list was %NULL
252 g_list_append (GList *list,
258 new_list = _g_list_alloc ();
259 new_list->data = data;
260 new_list->next = NULL;
264 last = g_list_last (list);
265 /* g_assert (last != NULL); */
266 last->next = new_list;
267 new_list->prev = last;
273 new_list->prev = NULL;
280 * @list: a pointer to a #GList, this must point to the top of the list
281 * @data: the data for the new element
283 * Prepends a new element on to the start of the list.
285 * Note that the return value is the new start of the list,
286 * which will have changed, so make sure you store the new value.
288 * |[<!-- language="C" -->
289 * /* Notice that it is initialized to the empty list. */
290 * GList *list = NULL;
292 * list = g_list_prepend (list, "last");
293 * list = g_list_prepend (list, "first");
296 * Do not use this function to prepend a new element to a different
297 * element than the start of the list. Use g_list_insert_before() instead.
299 * Returns: a pointer to the newly prepended element, which is the new
300 * start of the #GList
303 g_list_prepend (GList *list,
308 new_list = _g_list_alloc ();
309 new_list->data = data;
310 new_list->next = list;
314 new_list->prev = list->prev;
316 list->prev->next = new_list;
317 list->prev = new_list;
320 new_list->prev = NULL;
327 * @list: a pointer to a #GList, this must point to the top of the list
328 * @data: the data for the new element
329 * @position: the position to insert the element. If this is
330 * negative, or is larger than the number of elements in the
331 * list, the new element is added on to the end of the list.
333 * Inserts a new element into the list at the given position.
335 * Returns: the (possibly changed) start of the #GList
338 g_list_insert (GList *list,
346 return g_list_append (list, data);
347 else if (position == 0)
348 return g_list_prepend (list, data);
350 tmp_list = g_list_nth (list, position);
352 return g_list_append (list, data);
354 new_list = _g_list_alloc ();
355 new_list->data = data;
356 new_list->prev = tmp_list->prev;
357 tmp_list->prev->next = new_list;
358 new_list->next = tmp_list;
359 tmp_list->prev = new_list;
365 * g_list_insert_before:
366 * @list: a pointer to a #GList, this must point to the top of the list
367 * @sibling: the list element before which the new element
368 * is inserted or %NULL to insert at the end of the list
369 * @data: the data for the new element
371 * Inserts a new element into the list before the given position.
373 * Returns: the (possibly changed) start of the #GList
376 g_list_insert_before (GList *list,
382 list = g_list_alloc ();
384 g_return_val_if_fail (sibling == NULL, list);
391 node = _g_list_alloc ();
393 node->prev = sibling->prev;
394 node->next = sibling;
395 sibling->prev = node;
398 node->prev->next = node;
403 g_return_val_if_fail (sibling == list, node);
415 last->next = _g_list_alloc ();
416 last->next->data = data;
417 last->next->prev = last;
418 last->next->next = NULL;
426 * @list1: a #GList, this must point to the top of the list
427 * @list2: the #GList to add to the end of the first #GList,
428 * this must point to the top of the list
430 * Adds the second #GList onto the end of the first #GList.
431 * Note that the elements of the second #GList are not copied.
432 * They are used directly.
434 * This function is for example used to move an element in the list.
435 * The following example moves an element to the top of the list:
436 * |[<!-- language="C" -->
437 * list = g_list_remove_link (list, llink);
438 * list = g_list_concat (llink, list);
441 * Returns: the start of the new #GList, which equals @list1 if not %NULL
444 g_list_concat (GList *list1,
451 tmp_list = g_list_last (list1);
453 tmp_list->next = list2;
456 list2->prev = tmp_list;
462 static inline GList *
463 _g_list_remove_link (GList *list,
471 if (link->prev->next == link)
472 link->prev->next = link->next;
474 g_warning ("corrupted double-linked list detected");
478 if (link->next->prev == link)
479 link->next->prev = link->prev;
481 g_warning ("corrupted double-linked list detected");
495 * @list: a #GList, this must point to the top of the list
496 * @data: the data of the element to remove
498 * Removes an element from a #GList.
499 * If two elements contain the same data, only the first is removed.
500 * If none of the elements contain the data, the #GList is unchanged.
502 * Returns: the (possibly changed) start of the #GList
505 g_list_remove (GList *list,
513 if (tmp->data != data)
517 list = _g_list_remove_link (list, tmp);
528 * @list: a #GList, this must point to the top of the list
529 * @data: data to remove
531 * Removes all list nodes with data equal to @data.
532 * Returns the new head of the list. Contrast with
533 * g_list_remove() which removes only the first node
534 * matching the given data.
536 * Returns: the (possibly changed) start of the #GList
539 g_list_remove_all (GList *list,
546 if (tmp->data != data)
550 GList *next = tmp->next;
553 tmp->prev->next = next;
557 next->prev = tmp->prev;
567 * g_list_remove_link:
568 * @list: a #GList, this must point to the top of the list
569 * @llink: an element in the #GList
571 * Removes an element from a #GList, without freeing the element.
572 * The removed element's prev and next links are set to %NULL, so
573 * that it becomes a self-contained list with one element.
575 * This function is for example used to move an element in the list
576 * (see the example for g_list_concat()) or to remove an element in
577 * the list before freeing its data:
578 * |[<!-- language="C" -->
579 * list = g_list_remove_link (list, llink);
580 * free_some_data_that_may_access_the_list_again (llink->data);
581 * g_list_free (llink);
584 * Returns: the (possibly changed) start of the #GList
587 g_list_remove_link (GList *list,
590 return _g_list_remove_link (list, llink);
594 * g_list_delete_link:
595 * @list: a #GList, this must point to the top of the list
596 * @link_: node to delete from @list
598 * Removes the node link_ from the list and frees it.
599 * Compare this to g_list_remove_link() which removes the node
600 * without freeing it.
602 * Returns: the (possibly changed) start of the #GList
605 g_list_delete_link (GList *list,
608 list = _g_list_remove_link (list, link_);
609 _g_list_free1 (link_);
616 * @list: a #GList, this must point to the top of the list
620 * Note that this is a "shallow" copy. If the list elements
621 * consist of pointers to data, the pointers are copied but
622 * the actual data is not. See g_list_copy_deep() if you need
623 * to copy the data as well.
625 * Returns: the start of the new list that holds the same data as @list
628 g_list_copy (GList *list)
630 return g_list_copy_deep (list, NULL, NULL);
635 * @list: a #GList, this must point to the top of the list
636 * @func: a copy function used to copy every element in the list
637 * @user_data: user data passed to the copy function @func, or %NULL
639 * Makes a full (deep) copy of a #GList.
641 * In contrast with g_list_copy(), this function uses @func to make
642 * a copy of each list element, in addition to copying the list
645 * @func, as a #GCopyFunc, takes two arguments, the data to be copied
646 * and a @user_data pointer. It's safe to pass %NULL as user_data,
647 * if the copy function takes only one argument.
649 * For instance, if @list holds a list of GObjects, you can do:
650 * |[<!-- language="C" -->
651 * another_list = g_list_copy_deep (list, (GCopyFunc) g_object_ref, NULL);
654 * And, to entirely free the new list, you could do:
655 * |[<!-- language="C" -->
656 * g_list_free_full (another_list, g_object_unref);
659 * Returns: the start of the new list that holds a full copy of @list,
660 * use g_list_free_full() to free it
665 g_list_copy_deep (GList *list,
669 GList *new_list = NULL;
675 new_list = _g_list_alloc ();
677 new_list->data = func (list->data, user_data);
679 new_list->data = list->data;
680 new_list->prev = NULL;
685 last->next = _g_list_alloc ();
686 last->next->prev = last;
689 last->data = func (list->data, user_data);
691 last->data = list->data;
702 * @list: a #GList, this must point to the top of the list
705 * It simply switches the next and prev pointers of each element.
707 * Returns: the start of the reversed #GList
710 g_list_reverse (GList *list)
719 last->next = last->prev;
728 * @list: a #GList, this must point to the top of the list
729 * @n: the position of the element, counting from 0
731 * Gets the element at the given position in a #GList.
733 * Returns: the element, or %NULL if the position is off
734 * the end of the #GList
737 g_list_nth (GList *list,
740 while ((n-- > 0) && list)
749 * @n: the position of the element, counting from 0
751 * Gets the element @n places before @list.
753 * Returns: the element, or %NULL if the position is
754 * off the end of the #GList
757 g_list_nth_prev (GList *list,
760 while ((n-- > 0) && list)
768 * @list: a #GList, this must point to the top of the list
769 * @n: the position of the element
771 * Gets the data of the element at the given position.
773 * Returns: the element's data, or %NULL if the position
774 * is off the end of the #GList
777 g_list_nth_data (GList *list,
780 while ((n-- > 0) && list)
783 return list ? list->data : NULL;
788 * @list: a #GList, this must point to the top of the list
789 * @data: the element data to find
791 * Finds the element in a #GList which contains the given data.
793 * Returns: the found #GList element, or %NULL if it is not found
796 g_list_find (GList *list,
801 if (list->data == data)
810 * g_list_find_custom:
811 * @list: a #GList, this must point to the top of the list
812 * @data: user data passed to the function
813 * @func: the function to call for each element.
814 * It should return 0 when the desired element is found
816 * Finds an element in a #GList, using a supplied function to
817 * find the desired element. It iterates over the list, calling
818 * the given function which should return 0 when the desired
819 * element is found. The function takes two #gconstpointer arguments,
820 * the #GList element's data as the first argument and the
823 * Returns: the found #GList element, or %NULL if it is not found
826 g_list_find_custom (GList *list,
830 g_return_val_if_fail (func != NULL, list);
834 if (! func (list->data, data))
844 * @list: a #GList, this must point to the top of the list
845 * @llink: an element in the #GList
847 * Gets the position of the given element
848 * in the #GList (starting from 0).
850 * Returns: the position of the element in the #GList,
851 * or -1 if the element is not found
854 g_list_position (GList *list,
873 * @list: a #GList, this must point to the top of the list
874 * @data: the data to find
876 * Gets the position of the element containing
877 * the given data (starting from 0).
879 * Returns: the index of the element containing the data,
880 * or -1 if the data is not found
883 g_list_index (GList *list,
891 if (list->data == data)
902 * @list: any #GList element
904 * Gets the last element in a #GList.
906 * Returns: the last element in the #GList,
907 * or %NULL if the #GList has no elements
910 g_list_last (GList *list)
923 * @list: any #GList element
925 * Gets the first element in a #GList.
927 * Returns: the first element in the #GList,
928 * or %NULL if the #GList has no elements
931 g_list_first (GList *list)
944 * @list: a #GList, this must point to the top of the list
946 * Gets the number of elements in a #GList.
948 * This function iterates over the whole list to count its elements.
949 * Use a #GQueue instead of a GList if you regularly need the number
952 * Returns: the number of elements in the #GList
955 g_list_length (GList *list)
971 * @list: a #GList, this must point to the top of the list
972 * @func: the function to call with each element's data
973 * @user_data: user data to pass to the function
975 * Calls a function for each element of a #GList.
979 * @data: the element's data
980 * @user_data: user data passed to g_list_foreach() or g_slist_foreach()
982 * Specifies the type of functions passed to g_list_foreach() and
986 g_list_foreach (GList *list,
992 GList *next = list->next;
993 (*func) (list->data, user_data);
999 g_list_insert_sorted_real (GList *list,
1004 GList *tmp_list = list;
1008 g_return_val_if_fail (func != NULL, list);
1012 new_list = _g_list_alloc0 ();
1013 new_list->data = data;
1017 cmp = ((GCompareDataFunc) func) (data, tmp_list->data, user_data);
1019 while ((tmp_list->next) && (cmp > 0))
1021 tmp_list = tmp_list->next;
1023 cmp = ((GCompareDataFunc) func) (data, tmp_list->data, user_data);
1026 new_list = _g_list_alloc0 ();
1027 new_list->data = data;
1029 if ((!tmp_list->next) && (cmp > 0))
1031 tmp_list->next = new_list;
1032 new_list->prev = tmp_list;
1038 tmp_list->prev->next = new_list;
1039 new_list->prev = tmp_list->prev;
1041 new_list->next = tmp_list;
1042 tmp_list->prev = new_list;
1044 if (tmp_list == list)
1051 * g_list_insert_sorted:
1052 * @list: a pointer to a #GList, this must point to the top of the
1053 * already sorted list
1054 * @data: the data for the new element
1055 * @func: the function to compare elements in the list. It should
1056 * return a number > 0 if the first parameter comes after the
1057 * second parameter in the sort order.
1059 * Inserts a new element into the list, using the given comparison
1060 * function to determine its position.
1062 * If you are adding many new elements to a list, and the number of
1063 * new elements is much larger than the length of the list, use
1064 * g_list_prepend() to add the new items and sort the list afterwards
1065 * with g_list_sort().
1067 * Returns: the (possibly changed) start of the #GList
1070 g_list_insert_sorted (GList *list,
1074 return g_list_insert_sorted_real (list, data, (GFunc) func, NULL);
1078 * g_list_insert_sorted_with_data:
1079 * @list: a pointer to a #GList, this must point to the top of the
1080 * already sorted list
1081 * @data: the data for the new element
1082 * @func: the function to compare elements in the list. It should
1083 * return a number > 0 if the first parameter comes after the
1084 * second parameter in the sort order.
1085 * @user_data: user data to pass to comparison function
1087 * Inserts a new element into the list, using the given comparison
1088 * function to determine its position.
1090 * If you are adding many new elements to a list, and the number of
1091 * new elements is much larger than the length of the list, use
1092 * g_list_prepend() to add the new items and sort the list afterwards
1093 * with g_list_sort().
1095 * Returns: the (possibly changed) start of the #GList
1100 g_list_insert_sorted_with_data (GList *list,
1102 GCompareDataFunc func,
1105 return g_list_insert_sorted_real (list, data, (GFunc) func, user_data);
1109 g_list_sort_merge (GList *l1,
1114 GList list, *l, *lprev;
1122 cmp = ((GCompareDataFunc) compare_func) (l1->data, l2->data, user_data);
1138 l->next = l1 ? l1 : l2;
1145 g_list_sort_real (GList *list,
1159 while ((l2 = l2->next) != NULL)
1161 if ((l2 = l2->next) == NULL)
1168 return g_list_sort_merge (g_list_sort_real (list, compare_func, user_data),
1169 g_list_sort_real (l2, compare_func, user_data),
1176 * @list: a #GList, this must point to the top of the list
1177 * @compare_func: the comparison function used to sort the #GList.
1178 * This function is passed the data from 2 elements of the #GList
1179 * and should return 0 if they are equal, a negative value if the
1180 * first element comes before the second, or a positive value if
1181 * the first element comes after the second.
1183 * Sorts a #GList using the given comparison function. The algorithm
1184 * used is a stable sort.
1186 * Returns: the (possibly changed) start of the #GList
1191 * @b: a value to compare with
1193 * Specifies the type of a comparison function used to compare two
1194 * values. The function should return a negative integer if the first
1195 * value comes before the second, 0 if they are equal, or a positive
1196 * integer if the first value comes after the second.
1198 * Returns: negative value if @a < @b; zero if @a = @b; positive
1202 g_list_sort (GList *list,
1203 GCompareFunc compare_func)
1205 return g_list_sort_real (list, (GFunc) compare_func, NULL);
1209 * g_list_sort_with_data:
1210 * @list: a #GList, this must point to the top of the list
1211 * @compare_func: comparison function
1212 * @user_data: user data to pass to comparison function
1214 * Like g_list_sort(), but the comparison function accepts
1215 * a user data argument.
1217 * Returns: the (possibly changed) start of the #GList
1222 * @b: a value to compare with
1223 * @user_data: user data
1225 * Specifies the type of a comparison function used to compare two
1226 * values. The function should return a negative integer if the first
1227 * value comes before the second, 0 if they are equal, or a positive
1228 * integer if the first value comes after the second.
1230 * Returns: negative value if @a < @b; zero if @a = @b; positive
1234 g_list_sort_with_data (GList *list,
1235 GCompareDataFunc compare_func,
1238 return g_list_sort_real (list, (GFunc) compare_func, user_data);