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, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
21 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
22 * file for a list of people on the GLib Team. See the ChangeLog
23 * files for a list of changes. These files are distributed with
24 * GLib at ftp://ftp.gtk.org/pub/gtk/.
35 #include "gmessages.h"
37 #include "gtestutils.h"
40 * SECTION:linked_lists_double
41 * @title: Doubly-Linked Lists
42 * @short_description: linked lists that can be iterated over in both directions
44 * The #GList structure and its associated functions provide a standard
45 * doubly-linked list data structure.
47 * Each element in the list contains a piece of data, together with
48 * pointers which link to the previous and next elements in the list.
49 * Using these pointers it is possible to move through the list in both
50 * directions (unlike the <link
51 * linkend="glib-Singly-Linked-Lists">Singly-Linked Lists</link> which
52 * only allows movement through the list in the forward direction).
54 * The double linked list does not keep track of the number of items
55 * and does not keep track of both the start and end of the list. If
56 * you want fast access to both the start and the end of the list,
57 * and/or the number of items in the list, use <link
58 * linkend="glib-Double-ended-Queues.html">Double ended Queues</link>.
60 * The data contained in each element can be either integer values, by
61 * using one of the <link linkend="glib-Type-Conversion-Macros">Type
62 * Conversion Macros</link>, or simply pointers to any type of data.
64 * List elements are allocated from the <link
65 * linkend="glib-Memory-Slices">slice allocator</link>, which is more
66 * efficient than allocating elements individually.
68 * Note that most of the #GList functions expect to be passed a pointer
69 * to the first element in the list. The functions which insert
70 * elements return the new start of the list, which may have changed.
72 * There is no function to create a #GList. %NULL is considered to be
73 * the empty list so you simply set a #GList* to %NULL.
75 * To add elements, use g_list_append(), g_list_prepend(),
76 * g_list_insert() and g_list_insert_sorted().
78 * To visit all elements in the list, use a loop over the list:
81 * for (tmplist = list; tmplist; tmplist = tmplist->next) {
82 * /* do something with tmplist->data */
86 * To call a function for each element in the list use g_list_foreach().
88 * To loop over the list and modify it (e.g. remove a certain element)
89 * a while loop is more appropriate, for example:
91 * GList *tmplist = list;
93 * GList *nextlist = tmplist->next;
94 * if (specialcondition) {
95 * /* possibly free tmplist->data */
96 * list = g_list_delete_link (list, tmplist);
102 * To remove elements, use g_list_remove().
104 * To find elements in the list use g_list_first(), g_list_last(),
105 * g_list_next(), g_list_previous(), g_list_nth(), g_list_nth_data(),
106 * g_list_find() and g_list_find_custom().
108 * To find the index of an element use g_list_position() and
111 * To free the entire list, use g_list_free().
116 * @data: holds the element's data, which can be a pointer to any kind
117 * of data, or any integer value using the <link
118 * linkend="glib-Type-Conversion-Macros">Type Conversion
120 * @next: contains the link to the next element in the list.
121 * @prev: contains the link to the previous element in the list.
123 * The #GList struct is used for each element in a doubly-linked list.
128 * @list: an element in a #GList.
130 * A convenience macro to get the previous element in a #GList.
132 * Returns: the previous element, or %NULL if there are no previous
138 * @list: an element in a #GList.
140 * A convenience macro to get the next element in a #GList.
142 * Returns: the next element, or %NULL if there are no more elements.
145 #define _g_list_alloc() g_slice_new (GList)
146 #define _g_list_alloc0() g_slice_new0 (GList)
147 #define _g_list_free1(list) g_slice_free (GList, list)
152 * Allocates space for one #GList element. It is called by
153 * g_list_append(), g_list_prepend(), g_list_insert() and
154 * g_list_insert_sorted() and so is rarely used on its own.
156 * Returns: a pointer to the newly-allocated #GList element.
161 return _g_list_alloc0 ();
168 * Frees all of the memory used by a #GList.
169 * The freed elements are returned to the slice allocator.
172 * If list elements contain dynamically-allocated memory,
173 * you should either use g_list_free_full() or free them manually
178 g_list_free (GList *list)
180 g_slice_free_chain (GList, list, next);
185 * @list: a #GList element
187 * Frees one #GList element.
188 * It is usually used after g_list_remove_link().
193 * Another name for g_list_free_1().
196 g_list_free_1 (GList *list)
198 _g_list_free1 (list);
203 * @list: a pointer to a #GList
204 * @free_func: the function to be called to free each element's data
206 * Convenience method, which frees all the memory used by a #GList, and
207 * calls the specified destroy function on every element's data.
212 g_list_free_full (GList *list,
213 GDestroyNotify free_func)
215 g_list_foreach (list, (GFunc) free_func, NULL);
221 * @list: a pointer to a #GList
222 * @data: the data for the new element
224 * Adds a new element on to the end of the list.
227 * The return value is either @list, or the new start of the list if @list
228 * was %NULL; make sure you store the new value.
232 * Note that g_list_append() has to traverse the entire list
233 * to find the end, which is inefficient when adding multiple
234 * elements. A common idiom to avoid the inefficiency is to use
235 * g_list_prepend() and reverse the list with g_list_reverse()
236 * when all elements have been added.
240 * /* Notice that these are initialized to the empty list. */
241 * GList *list = NULL, *number_list = NULL;
243 * /* This is a list of strings. */
244 * list = g_list_append (list, "first");
245 * list = g_list_append (list, "second");
247 * /* This is a list of integers. */
248 * number_list = g_list_append (number_list, GINT_TO_POINTER (27));
249 * number_list = g_list_append (number_list, GINT_TO_POINTER (14));
252 * Returns: either @list or the new start of the #GList if @list was %NULL
255 g_list_append (GList *list,
261 new_list = _g_list_alloc ();
262 new_list->data = data;
263 new_list->next = NULL;
267 last = g_list_last (list);
268 /* g_assert (last != NULL); */
269 last->next = new_list;
270 new_list->prev = last;
276 new_list->prev = NULL;
283 * @list: a pointer to a #GList, this must point to the top of the list
284 * @data: the data for the new element
286 * Prepends a new element on to the start of the list.
289 * The return value is the new start of the list, which
290 * will have changed, so make sure you store the new value.
294 * /* Notice that it is initialized to the empty list. */
295 * GList *list = NULL;
296 * list = g_list_prepend (list, "last");
297 * list = g_list_prepend (list, "first");
301 * Do not use this function to prepend a new element to a different element
302 * than the start of the list. Use g_list_insert_before() instead.
305 * Returns: a pointer to the newly prepended element, which is the new
306 * start of the #GList.
309 g_list_prepend (GList *list,
314 new_list = _g_list_alloc ();
315 new_list->data = data;
316 new_list->next = list;
320 new_list->prev = list->prev;
322 list->prev->next = new_list;
323 list->prev = new_list;
326 new_list->prev = NULL;
333 * @list: a pointer to a #GList, this must point to the top of the list
334 * @data: the data for the new element
335 * @position: the position to insert the element. If this is
336 * negative, or is larger than the number of elements in the
337 * list, the new element is added on to the end of the list.
339 * Inserts a new element into the list at the given position.
341 * Returns: the (possibly changed) start of the #GList
344 g_list_insert (GList *list,
352 return g_list_append (list, data);
353 else if (position == 0)
354 return g_list_prepend (list, data);
356 tmp_list = g_list_nth (list, position);
358 return g_list_append (list, data);
360 new_list = _g_list_alloc ();
361 new_list->data = data;
362 new_list->prev = tmp_list->prev;
363 tmp_list->prev->next = new_list;
364 new_list->next = tmp_list;
365 tmp_list->prev = new_list;
371 * g_list_insert_before:
372 * @list: a pointer to a #GList, this must point to the top of the list
373 * @sibling: the list element before which the new element
374 * is inserted or %NULL to insert at the end of the list
375 * @data: the data for the new element
377 * Inserts a new element into the list before the given position.
379 * Returns: the (possibly changed) start of the #GList
382 g_list_insert_before (GList *list,
388 list = g_list_alloc ();
390 g_return_val_if_fail (sibling == NULL, list);
397 node = _g_list_alloc ();
399 node->prev = sibling->prev;
400 node->next = sibling;
401 sibling->prev = node;
404 node->prev->next = node;
409 g_return_val_if_fail (sibling == list, node);
421 last->next = _g_list_alloc ();
422 last->next->data = data;
423 last->next->prev = last;
424 last->next->next = NULL;
432 * @list1: a #GList, this must point to the top of the list
433 * @list2: the #GList to add to the end of the first #GList, this must point
434 * to the top of the list
436 * Adds the second #GList onto the end of the first #GList.
437 * Note that the elements of the second #GList are not copied.
438 * They are used directly.
440 * This function is for example used to move an element in the list.
441 * The following example moves an element to the top of the list:
443 * list = g_list_remove_link (list, llink);
444 * list = g_list_concat (llink, list);
447 * Returns: the start of the new #GList, which equals @list1 if not %NULL
450 g_list_concat (GList *list1, GList *list2)
456 tmp_list = g_list_last (list1);
458 tmp_list->next = list2;
461 list2->prev = tmp_list;
468 _g_list_remove_link (GList *list,
476 if (link->prev->next == link)
477 link->prev->next = link->next;
479 g_warning ("corrupted double-linked list detected");
483 if (link->next->prev == link)
484 link->next->prev = link->prev;
486 g_warning ("corrupted double-linked list detected");
500 * @list: a #GList, this must point to the top of the list
501 * @data: the data of the element to remove
503 * Removes an element from a #GList.
504 * If two elements contain the same data, only the first is removed.
505 * If none of the elements contain the data, the #GList is unchanged.
507 * Returns: the (possibly changed) start of the #GList
510 g_list_remove (GList *list,
518 if (tmp->data != data)
522 list = _g_list_remove_link (list, tmp);
533 * @list: a #GList, this must point to the top of the list
534 * @data: data to remove
536 * Removes all list nodes with data equal to @data.
537 * Returns the new head of the list. Contrast with
538 * g_list_remove() which removes only the first node
539 * matching the given data.
541 * Returns: the (possibly changed) start of the #GList
544 g_list_remove_all (GList *list,
551 if (tmp->data != data)
555 GList *next = tmp->next;
558 tmp->prev->next = next;
562 next->prev = tmp->prev;
572 * g_list_remove_link:
573 * @list: a #GList, this must point to the top of the list
574 * @llink: an element in the #GList
576 * Removes an element from a #GList, without freeing the element.
577 * The removed element's prev and next links are set to %NULL, so
578 * that it becomes a self-contained list with one element.
580 * This function is for example used to move an element in the list (see the
581 * example at g_list_concat()) or to remove an element in the list before
584 * list = g_list_remove_link (list, llink);
585 * free_some_data_that_may_access_the_list_again (llink->data);
586 * g_list_free (llink);
589 * Returns: the (possibly changed) start of the #GList
592 g_list_remove_link (GList *list,
595 return _g_list_remove_link (list, llink);
599 * g_list_delete_link:
600 * @list: a #GList, this must point to the top of the list
601 * @link_: node to delete from @list
603 * Removes the node link_ from the list and frees it.
604 * Compare this to g_list_remove_link() which removes the node
605 * without freeing it.
607 * Returns: the (possibly changed) start of the #GList
610 g_list_delete_link (GList *list,
613 list = _g_list_remove_link (list, link_);
614 _g_list_free1 (link_);
621 * @list: a #GList, this must point to the top of the list
626 * Note that this is a "shallow" copy. If the list elements
627 * consist of pointers to data, the pointers are copied but
628 * the actual data is not. See g_list_copy_deep() if you need
629 * to copy the data as well.
632 * Returns: the start of the new list that holds the same data as @list
635 g_list_copy (GList *list)
637 return g_list_copy_deep (list, NULL, NULL);
642 * @list: a #GList, this must point to the top of the list
643 * @func: a copy function used to copy every element in the list
644 * @user_data: user data passed to the copy function @func, or #NULL
646 * Makes a full (deep) copy of a #GList.
648 * In contrast with g_list_copy(), this function uses @func to make a copy of
649 * each list element, in addition to copying the list container itself.
651 * @func, as a #GCopyFunc, takes two arguments, the data to be copied and a user
652 * pointer. It's safe to pass #NULL as user_data, if the copy function takes only
655 * For instance, if @list holds a list of GObjects, you can do:
657 * another_list = g_list_copy_deep (list, (GCopyFunc) g_object_ref, NULL);
660 * And, to entirely free the new list, you could do:
662 * g_list_free_full (another_list, g_object_unref);
665 * Returns: the start of the new list that holds a full copy of @list,
666 * use #g_list_free_full to free it
671 g_list_copy_deep (GList *list, GCopyFunc func, gpointer user_data)
673 GList *new_list = NULL;
679 new_list = _g_list_alloc ();
681 new_list->data = func (list->data, user_data);
683 new_list->data = list->data;
684 new_list->prev = NULL;
689 last->next = _g_list_alloc ();
690 last->next->prev = last;
693 last->data = func (list->data, user_data);
695 last->data = list->data;
706 * @list: a #GList, this must point to the top of the list
709 * It simply switches the next and prev pointers of each element.
711 * Returns: the start of the reversed #GList
714 g_list_reverse (GList *list)
723 last->next = last->prev;
732 * @list: a #GList, this must point to the top of the list
733 * @n: the position of the element, counting from 0
735 * Gets the element at the given position in a #GList.
737 * Returns: the element, or %NULL if the position is off
738 * the end of the #GList
741 g_list_nth (GList *list,
744 while ((n-- > 0) && list)
753 * @n: the position of the element, counting from 0
755 * Gets the element @n places before @list.
757 * Returns: the element, or %NULL if the position is
758 * off the end of the #GList
761 g_list_nth_prev (GList *list,
764 while ((n-- > 0) && list)
772 * @list: a #GList, this must point to the top of the list
773 * @n: the position of the element
775 * Gets the data of the element at the given position.
777 * Returns: the element's data, or %NULL if the position
778 * is off the end of the #GList
781 g_list_nth_data (GList *list,
784 while ((n-- > 0) && list)
787 return list ? list->data : NULL;
792 * @list: a #GList, this must point to the top of the list
793 * @data: the element data to find
795 * Finds the element in a #GList which
796 * contains the given data.
798 * Returns: the found #GList element,
799 * or %NULL if it is not found
802 g_list_find (GList *list,
807 if (list->data == data)
816 * g_list_find_custom:
817 * @list: a #GList, this must point to the top of the list
818 * @data: user data passed to the function
819 * @func: the function to call for each element.
820 * It should return 0 when the desired element is found
822 * Finds an element in a #GList, using a supplied function to
823 * find the desired element. It iterates over the list, calling
824 * the given function which should return 0 when the desired
825 * element is found. The function takes two #gconstpointer arguments,
826 * the #GList element's data as the first argument and the
829 * Returns: the found #GList element, or %NULL if it is not found
832 g_list_find_custom (GList *list,
836 g_return_val_if_fail (func != NULL, list);
840 if (! func (list->data, data))
851 * @list: a #GList, this must point to the top of the list
852 * @llink: an element in the #GList
854 * Gets the position of the given element
855 * in the #GList (starting from 0).
857 * Returns: the position of the element in the #GList,
858 * or -1 if the element is not found
861 g_list_position (GList *list,
880 * @list: a #GList, this must point to the top of the list
881 * @data: the data to find
883 * Gets the position of the element containing
884 * the given data (starting from 0).
886 * Returns: the index of the element containing the data,
887 * or -1 if the data is not found
890 g_list_index (GList *list,
898 if (list->data == data)
909 * @list: any #GList element
911 * Gets the last element in a #GList.
913 * Returns: the last element in the #GList,
914 * or %NULL if the #GList has no elements
917 g_list_last (GList *list)
930 * @list: any #GList element
932 * Gets the first element in a #GList.
934 * Returns: the first element in the #GList,
935 * or %NULL if the #GList has no elements
938 g_list_first (GList *list)
951 * @list: a #GList, this must point to the top of the list
953 * Gets the number of elements in a #GList.
956 * This function iterates over the whole list to
957 * count its elements. Use <link
958 * linkend="glib-Double-ended-Queues.html">Double ended Queues</link> instead
959 * of a double linked list if you regularly need the number of items.
962 * Returns: the number of elements in the #GList
965 g_list_length (GList *list)
981 * @list: a #GList, this must point to the top of the list
982 * @func: the function to call with each element's data
983 * @user_data: user data to pass to the function
985 * Calls a function for each element of a #GList.
989 * @data: the element's data.
990 * @user_data: user data passed to g_list_foreach() or
993 * Specifies the type of functions passed to g_list_foreach() and
997 g_list_foreach (GList *list,
1003 GList *next = list->next;
1004 (*func) (list->data, user_data);
1010 g_list_insert_sorted_real (GList *list,
1015 GList *tmp_list = list;
1019 g_return_val_if_fail (func != NULL, list);
1023 new_list = _g_list_alloc0 ();
1024 new_list->data = data;
1028 cmp = ((GCompareDataFunc) func) (data, tmp_list->data, user_data);
1030 while ((tmp_list->next) && (cmp > 0))
1032 tmp_list = tmp_list->next;
1034 cmp = ((GCompareDataFunc) func) (data, tmp_list->data, user_data);
1037 new_list = _g_list_alloc0 ();
1038 new_list->data = data;
1040 if ((!tmp_list->next) && (cmp > 0))
1042 tmp_list->next = new_list;
1043 new_list->prev = tmp_list;
1049 tmp_list->prev->next = new_list;
1050 new_list->prev = tmp_list->prev;
1052 new_list->next = tmp_list;
1053 tmp_list->prev = new_list;
1055 if (tmp_list == list)
1062 * g_list_insert_sorted:
1063 * @list: a pointer to a #GList, this must point to the top of the already
1065 * @data: the data for the new element
1066 * @func: the function to compare elements in the list. It should
1067 * return a number > 0 if the first parameter comes after the
1068 * second parameter in the sort order.
1070 * Inserts a new element into the list, using the given comparison
1071 * function to determine its position.
1074 * If you are adding many new elements to a list, and the number of new
1075 * elements is much larger than the length of the list, use g_list_prepend()
1076 * to add the new items and sort the list afterwards with g_list_sort()
1079 * Returns: the (possibly changed) start of the #GList
1082 g_list_insert_sorted (GList *list,
1086 return g_list_insert_sorted_real (list, data, (GFunc) func, NULL);
1090 * g_list_insert_sorted_with_data:
1091 * @list: a pointer to a #GList, this must point to the top of the list
1092 * @data: the data for the new element
1093 * @func: the function to compare elements in the list.
1094 * It should return a number > 0 if the first parameter
1095 * comes after the second parameter in the sort order.
1096 * @user_data: user data to pass to comparison function.
1098 * Inserts a new element into the list, using the given comparison
1099 * function to determine its position.
1101 * Returns: the (possibly changed) start of the #GList
1106 g_list_insert_sorted_with_data (GList *list,
1108 GCompareDataFunc func,
1111 return g_list_insert_sorted_real (list, data, (GFunc) func, user_data);
1115 g_list_sort_merge (GList *l1,
1120 GList list, *l, *lprev;
1128 cmp = ((GCompareDataFunc) compare_func) (l1->data, l2->data, user_data);
1144 l->next = l1 ? l1 : l2;
1151 g_list_sort_real (GList *list,
1165 while ((l2 = l2->next) != NULL)
1167 if ((l2 = l2->next) == NULL)
1174 return g_list_sort_merge (g_list_sort_real (list, compare_func, user_data),
1175 g_list_sort_real (l2, compare_func, user_data),
1182 * @list: a #GList, this must point to the top of the list
1183 * @compare_func: the comparison function used to sort the #GList.
1184 * This function is passed the data from 2 elements of the #GList
1185 * and should return 0 if they are equal, a negative value if the
1186 * first element comes before the second, or a positive value if
1187 * the first element comes after the second.
1189 * Sorts a #GList using the given comparison function. The algorithm
1190 * used is a stable sort.
1192 * Returns: the (possibly changed) start of the #GList
1197 * @b: a value to compare with.
1199 * Specifies the type of a comparison function used to compare two
1200 * values. The function should return a negative integer if the first
1201 * value comes before the second, 0 if they are equal, or a positive
1202 * integer if the first value comes after the second.
1204 * Returns: negative value if @a < @b; zero if @a = @b; positive
1208 g_list_sort (GList *list,
1209 GCompareFunc compare_func)
1211 return g_list_sort_real (list, (GFunc) compare_func, NULL);
1216 * g_list_sort_with_data:
1217 * @list: a #GList, this must point to the top of the list
1218 * @compare_func: comparison function
1219 * @user_data: user data to pass to comparison function
1221 * Like g_list_sort(), but the comparison function accepts
1222 * a user data argument.
1224 * Returns: the (possibly changed) start of the #GList
1229 * @b: a value to compare with.
1230 * @user_data: user data to pass to comparison function.
1232 * Specifies the type of a comparison function used to compare two
1233 * values. The function should return a negative integer if the first
1234 * value comes before the second, 0 if they are equal, or a positive
1235 * integer if the first value comes after the second.
1237 * Returns: negative value if @a < @b; zero if @a = @b; positive
1241 g_list_sort_with_data (GList *list,
1242 GCompareDataFunc compare_func,
1245 return g_list_sort_real (list, (GFunc) compare_func, user_data);