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 <link
49 * linkend="glib-Singly-Linked-Lists">#GSList</link> which
50 * only allows movement through the list in the forward direction).
52 * The double linked list does not keep track of the number of items
53 * and does not keep track of both the start and end of the list. If
54 * you want fast access to both the start and the end of the list,
55 * and/or the number of items in the list, use a
56 * <link linkend="glib-Double-ended-Queues">GQueue</link> instead.
58 * The data contained in each element can be either integer values, by
59 * using one of the <link linkend="glib-Type-Conversion-Macros">Type
60 * Conversion Macros</link>, or simply pointers to any type of data.
62 * List elements are allocated from the <link
63 * linkend="glib-Memory-Slices">slice allocator</link>, which is more
64 * efficient than allocating elements individually.
66 * Note that most of the #GList functions expect to be passed a pointer
67 * to the first element in the list. The functions which insert
68 * elements return the new start of the list, which may have changed.
70 * There is no function to create a #GList. %NULL is considered to be
71 * a valid, empty list so you simply set a #GList* to %NULL to initialize
74 * To add elements, use g_list_append(), g_list_prepend(),
75 * g_list_insert() and g_list_insert_sorted().
77 * To visit all elements in the list, use a loop over the list:
78 * |[<!-- language="C" -->
80 * for (l = list; l != NULL; l = l->next)
82 * /* do something with l->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:
90 * |[<!-- language="C" -->
94 * GList *next = l->next;
95 * if (should_be_removed (l))
97 * /* possibly free l->data */
98 * list = g_list_delete_link (list, l);
104 * To remove elements, use g_list_remove().
106 * To navigate in a list, use g_list_first(), g_list_last(),
107 * g_list_next(), g_list_previous().
109 * To find elements in the list use g_list_nth(), g_list_nth_data(),
110 * g_list_find() and g_list_find_custom().
112 * To find the index of an element use g_list_position() and
115 * To free the entire list, use g_list_free() or g_list_free_full().
120 * @data: holds the element's data, which can be a pointer to any kind
121 * of data, or any integer value using the <link
122 * linkend="glib-Type-Conversion-Macros">Type Conversion
124 * @next: contains the link to the next element in the list
125 * @prev: contains the link to the previous element in the list
127 * The #GList struct is used for each element in a doubly-linked list.
132 * @list: an element in a #GList
134 * A convenience macro to get the previous element in a #GList.
135 * Note that it is considered perfectly acceptable to access
136 * @list->previous directly.
138 * Returns: the previous element, or %NULL if there are no previous
144 * @list: an element in a #GList
146 * A convenience macro to get the next element in a #GList.
147 * Note that it is considered perfectly acceptable to access
148 * @list->next directly.
150 * Returns: the next element, or %NULL if there are no more elements
153 #define _g_list_alloc() g_slice_new (GList)
154 #define _g_list_alloc0() g_slice_new0 (GList)
155 #define _g_list_free1(list) g_slice_free (GList, list)
160 * Allocates space for one #GList element. It is called by
161 * g_list_append(), g_list_prepend(), g_list_insert() and
162 * g_list_insert_sorted() and so is rarely used on its own.
164 * Returns: a pointer to the newly-allocated #GList element
169 return _g_list_alloc0 ();
176 * Frees all of the memory used by a #GList.
177 * The freed elements are returned to the slice allocator.
179 * If list elements contain dynamically-allocated memory, you should
180 * either use g_list_free_full() or free them manually first.
183 g_list_free (GList *list)
185 g_slice_free_chain (GList, list, next);
190 * @list: a #GList element
192 * Frees one #GList element.
193 * It is usually used after g_list_remove_link().
198 * Another name for g_list_free_1().
201 g_list_free_1 (GList *list)
203 _g_list_free1 (list);
208 * @list: a pointer to a #GList
209 * @free_func: the function to be called to free each element's data
211 * Convenience method, which frees all the memory used by a #GList,
212 * and calls @free_func on every element's data.
217 g_list_free_full (GList *list,
218 GDestroyNotify free_func)
220 g_list_foreach (list, (GFunc) free_func, NULL);
226 * @list: a pointer to a #GList
227 * @data: the data for the new element
229 * Adds a new element on to the end of the list.
231 * Note that the return value is the new start of the list,
232 * if @list was empty; make sure you store the new value.
234 * g_list_append() has to traverse the entire list to find the end,
235 * which is inefficient when adding multiple elements. A common idiom
236 * to avoid the inefficiency is to use g_list_prepend() and reverse
237 * the list with g_list_reverse() when all elements have been added.
239 * |[<!-- language="C" -->
240 * /* Notice that these are initialized to the empty list. */
241 * GList *string_list = NULL, *number_list = NULL;
243 * /* This is a list of strings. */
244 * string_list = g_list_append (string_list, "first");
245 * string_list = g_list_append (string_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.
288 * Note that the return value is the new start of the list,
289 * which will have changed, so make sure you store the new value.
291 * |[<!-- language="C" -->
292 * /* Notice that it is initialized to the empty list. */
293 * GList *list = NULL;
295 * list = g_list_prepend (list, "last");
296 * list = g_list_prepend (list, "first");
299 * Do not use this function to prepend a new element to a different
300 * element than the start of the list. Use g_list_insert_before() instead.
302 * Returns: a pointer to the newly prepended element, which is the new
303 * start of the #GList
306 g_list_prepend (GList *list,
311 new_list = _g_list_alloc ();
312 new_list->data = data;
313 new_list->next = list;
317 new_list->prev = list->prev;
319 list->prev->next = new_list;
320 list->prev = new_list;
323 new_list->prev = NULL;
330 * @list: a pointer to a #GList, this must point to the top of the list
331 * @data: the data for the new element
332 * @position: the position to insert the element. If this is
333 * negative, or is larger than the number of elements in the
334 * list, the new element is added on to the end of the list.
336 * Inserts a new element into the list at the given position.
338 * Returns: the (possibly changed) start of the #GList
341 g_list_insert (GList *list,
349 return g_list_append (list, data);
350 else if (position == 0)
351 return g_list_prepend (list, data);
353 tmp_list = g_list_nth (list, position);
355 return g_list_append (list, data);
357 new_list = _g_list_alloc ();
358 new_list->data = data;
359 new_list->prev = tmp_list->prev;
360 tmp_list->prev->next = new_list;
361 new_list->next = tmp_list;
362 tmp_list->prev = new_list;
368 * g_list_insert_before:
369 * @list: a pointer to a #GList, this must point to the top of the list
370 * @sibling: the list element before which the new element
371 * is inserted or %NULL to insert at the end of the list
372 * @data: the data for the new element
374 * Inserts a new element into the list before the given position.
376 * Returns: the (possibly changed) start of the #GList
379 g_list_insert_before (GList *list,
385 list = g_list_alloc ();
387 g_return_val_if_fail (sibling == NULL, list);
394 node = _g_list_alloc ();
396 node->prev = sibling->prev;
397 node->next = sibling;
398 sibling->prev = node;
401 node->prev->next = node;
406 g_return_val_if_fail (sibling == list, node);
418 last->next = _g_list_alloc ();
419 last->next->data = data;
420 last->next->prev = last;
421 last->next->next = NULL;
429 * @list1: a #GList, this must point to the top of the list
430 * @list2: the #GList to add to the end of the first #GList,
431 * this must point to the top of the list
433 * Adds the second #GList onto the end of the first #GList.
434 * Note that the elements of the second #GList are not copied.
435 * They are used directly.
437 * This function is for example used to move an element in the list.
438 * The following example moves an element to the top of the list:
439 * |[<!-- language="C" -->
440 * list = g_list_remove_link (list, llink);
441 * list = g_list_concat (llink, list);
444 * Returns: the start of the new #GList, which equals @list1 if not %NULL
447 g_list_concat (GList *list1,
454 tmp_list = g_list_last (list1);
456 tmp_list->next = list2;
459 list2->prev = tmp_list;
465 static inline GList *
466 _g_list_remove_link (GList *list,
474 if (link->prev->next == link)
475 link->prev->next = link->next;
477 g_warning ("corrupted double-linked list detected");
481 if (link->next->prev == link)
482 link->next->prev = link->prev;
484 g_warning ("corrupted double-linked list detected");
498 * @list: a #GList, this must point to the top of the list
499 * @data: the data of the element to remove
501 * Removes an element from a #GList.
502 * If two elements contain the same data, only the first is removed.
503 * If none of the elements contain the data, the #GList is unchanged.
505 * Returns: the (possibly changed) start of the #GList
508 g_list_remove (GList *list,
516 if (tmp->data != data)
520 list = _g_list_remove_link (list, tmp);
531 * @list: a #GList, this must point to the top of the list
532 * @data: data to remove
534 * Removes all list nodes with data equal to @data.
535 * Returns the new head of the list. Contrast with
536 * g_list_remove() which removes only the first node
537 * matching the given data.
539 * Returns: the (possibly changed) start of the #GList
542 g_list_remove_all (GList *list,
549 if (tmp->data != data)
553 GList *next = tmp->next;
556 tmp->prev->next = next;
560 next->prev = tmp->prev;
570 * g_list_remove_link:
571 * @list: a #GList, this must point to the top of the list
572 * @llink: an element in the #GList
574 * Removes an element from a #GList, without freeing the element.
575 * The removed element's prev and next links are set to %NULL, so
576 * that it becomes a self-contained list with one element.
578 * This function is for example used to move an element in the list
579 * (see the example for g_list_concat()) or to remove an element in
580 * the list before freeing its data:
581 * |[<!-- language="C" -->
582 * list = g_list_remove_link (list, llink);
583 * free_some_data_that_may_access_the_list_again (llink->data);
584 * g_list_free (llink);
587 * Returns: the (possibly changed) start of the #GList
590 g_list_remove_link (GList *list,
593 return _g_list_remove_link (list, llink);
597 * g_list_delete_link:
598 * @list: a #GList, this must point to the top of the list
599 * @link_: node to delete from @list
601 * Removes the node link_ from the list and frees it.
602 * Compare this to g_list_remove_link() which removes the node
603 * without freeing it.
605 * Returns: the (possibly changed) start of the #GList
608 g_list_delete_link (GList *list,
611 list = _g_list_remove_link (list, link_);
612 _g_list_free1 (link_);
619 * @list: a #GList, this must point to the top of the list
623 * Note that this is a "shallow" copy. If the list elements
624 * consist of pointers to data, the pointers are copied but
625 * the actual data is not. See g_list_copy_deep() if you need
626 * to copy the data as well.
628 * Returns: the start of the new list that holds the same data as @list
631 g_list_copy (GList *list)
633 return g_list_copy_deep (list, NULL, NULL);
638 * @list: a #GList, this must point to the top of the list
639 * @func: a copy function used to copy every element in the list
640 * @user_data: user data passed to the copy function @func, or %NULL
642 * Makes a full (deep) copy of a #GList.
644 * In contrast with g_list_copy(), this function uses @func to make
645 * a copy of each list element, in addition to copying the list
648 * @func, as a #GCopyFunc, takes two arguments, the data to be copied
649 * and a @user_data pointer. It's safe to pass %NULL as user_data,
650 * if the copy function takes only one argument.
652 * For instance, if @list holds a list of GObjects, you can do:
653 * |[<!-- language="C" -->
654 * another_list = g_list_copy_deep (list, (GCopyFunc) g_object_ref, NULL);
657 * And, to entirely free the new list, you could do:
658 * |[<!-- language="C" -->
659 * g_list_free_full (another_list, g_object_unref);
662 * Returns: the start of the new list that holds a full copy of @list,
663 * use g_list_free_full() to free it
668 g_list_copy_deep (GList *list,
672 GList *new_list = NULL;
678 new_list = _g_list_alloc ();
680 new_list->data = func (list->data, user_data);
682 new_list->data = list->data;
683 new_list->prev = NULL;
688 last->next = _g_list_alloc ();
689 last->next->prev = last;
692 last->data = func (list->data, user_data);
694 last->data = list->data;
705 * @list: a #GList, this must point to the top of the list
708 * It simply switches the next and prev pointers of each element.
710 * Returns: the start of the reversed #GList
713 g_list_reverse (GList *list)
722 last->next = last->prev;
731 * @list: a #GList, this must point to the top of the list
732 * @n: the position of the element, counting from 0
734 * Gets the element at the given position in a #GList.
736 * Returns: the element, or %NULL if the position is off
737 * the end of the #GList
740 g_list_nth (GList *list,
743 while ((n-- > 0) && list)
752 * @n: the position of the element, counting from 0
754 * Gets the element @n places before @list.
756 * Returns: the element, or %NULL if the position is
757 * off the end of the #GList
760 g_list_nth_prev (GList *list,
763 while ((n-- > 0) && list)
771 * @list: a #GList, this must point to the top of the list
772 * @n: the position of the element
774 * Gets the data of the element at the given position.
776 * Returns: the element's data, or %NULL if the position
777 * is off the end of the #GList
780 g_list_nth_data (GList *list,
783 while ((n-- > 0) && list)
786 return list ? list->data : NULL;
791 * @list: a #GList, this must point to the top of the list
792 * @data: the element data to find
794 * Finds the element in a #GList which contains the given data.
796 * Returns: the found #GList element, or %NULL if it is not found
799 g_list_find (GList *list,
804 if (list->data == data)
813 * g_list_find_custom:
814 * @list: a #GList, this must point to the top of the list
815 * @data: user data passed to the function
816 * @func: the function to call for each element.
817 * It should return 0 when the desired element is found
819 * Finds an element in a #GList, using a supplied function to
820 * find the desired element. It iterates over the list, calling
821 * the given function which should return 0 when the desired
822 * element is found. The function takes two #gconstpointer arguments,
823 * the #GList element's data as the first argument and the
826 * Returns: the found #GList element, or %NULL if it is not found
829 g_list_find_custom (GList *list,
833 g_return_val_if_fail (func != NULL, list);
837 if (! func (list->data, data))
847 * @list: a #GList, this must point to the top of the list
848 * @llink: an element in the #GList
850 * Gets the position of the given element
851 * in the #GList (starting from 0).
853 * Returns: the position of the element in the #GList,
854 * or -1 if the element is not found
857 g_list_position (GList *list,
876 * @list: a #GList, this must point to the top of the list
877 * @data: the data to find
879 * Gets the position of the element containing
880 * the given data (starting from 0).
882 * Returns: the index of the element containing the data,
883 * or -1 if the data is not found
886 g_list_index (GList *list,
894 if (list->data == data)
905 * @list: any #GList element
907 * Gets the last element in a #GList.
909 * Returns: the last element in the #GList,
910 * or %NULL if the #GList has no elements
913 g_list_last (GList *list)
926 * @list: any #GList element
928 * Gets the first element in a #GList.
930 * Returns: the first element in the #GList,
931 * or %NULL if the #GList has no elements
934 g_list_first (GList *list)
947 * @list: a #GList, this must point to the top of the list
949 * Gets the number of elements in a #GList.
951 * This function iterates over the whole list to count its elements.
952 * Use a #GQueue instead of a GList if you regularly need the number
955 * Returns: the number of elements in the #GList
958 g_list_length (GList *list)
974 * @list: a #GList, this must point to the top of the list
975 * @func: the function to call with each element's data
976 * @user_data: user data to pass to the function
978 * Calls a function for each element of a #GList.
982 * @data: the element's data
983 * @user_data: user data passed to g_list_foreach() or g_slist_foreach()
985 * Specifies the type of functions passed to g_list_foreach() and
989 g_list_foreach (GList *list,
995 GList *next = list->next;
996 (*func) (list->data, user_data);
1002 g_list_insert_sorted_real (GList *list,
1007 GList *tmp_list = list;
1011 g_return_val_if_fail (func != NULL, list);
1015 new_list = _g_list_alloc0 ();
1016 new_list->data = data;
1020 cmp = ((GCompareDataFunc) func) (data, tmp_list->data, user_data);
1022 while ((tmp_list->next) && (cmp > 0))
1024 tmp_list = tmp_list->next;
1026 cmp = ((GCompareDataFunc) func) (data, tmp_list->data, user_data);
1029 new_list = _g_list_alloc0 ();
1030 new_list->data = data;
1032 if ((!tmp_list->next) && (cmp > 0))
1034 tmp_list->next = new_list;
1035 new_list->prev = tmp_list;
1041 tmp_list->prev->next = new_list;
1042 new_list->prev = tmp_list->prev;
1044 new_list->next = tmp_list;
1045 tmp_list->prev = new_list;
1047 if (tmp_list == list)
1054 * g_list_insert_sorted:
1055 * @list: a pointer to a #GList, this must point to the top of the
1056 * already sorted list
1057 * @data: the data for the new element
1058 * @func: the function to compare elements in the list. It should
1059 * return a number > 0 if the first parameter comes after the
1060 * second parameter in the sort order.
1062 * Inserts a new element into the list, using the given comparison
1063 * function to determine its position.
1065 * If you are adding many new elements to a list, and the number of
1066 * new elements is much larger than the length of the list, use
1067 * g_list_prepend() to add the new items and sort the list afterwards
1068 * with g_list_sort().
1070 * Returns: the (possibly changed) start of the #GList
1073 g_list_insert_sorted (GList *list,
1077 return g_list_insert_sorted_real (list, data, (GFunc) func, NULL);
1081 * g_list_insert_sorted_with_data:
1082 * @list: a pointer to a #GList, this must point to the top of the
1083 * already sorted list
1084 * @data: the data for the new element
1085 * @func: the function to compare elements in the list. It should
1086 * return a number > 0 if the first parameter comes after the
1087 * second parameter in the sort order.
1088 * @user_data: user data to pass to comparison function
1090 * Inserts a new element into the list, using the given comparison
1091 * function to determine its position.
1093 * If you are adding many new elements to a list, and the number of
1094 * new elements is much larger than the length of the list, use
1095 * g_list_prepend() to add the new items and sort the list afterwards
1096 * with g_list_sort().
1098 * Returns: the (possibly changed) start of the #GList
1103 g_list_insert_sorted_with_data (GList *list,
1105 GCompareDataFunc func,
1108 return g_list_insert_sorted_real (list, data, (GFunc) func, user_data);
1112 g_list_sort_merge (GList *l1,
1117 GList list, *l, *lprev;
1125 cmp = ((GCompareDataFunc) compare_func) (l1->data, l2->data, user_data);
1141 l->next = l1 ? l1 : l2;
1148 g_list_sort_real (GList *list,
1162 while ((l2 = l2->next) != NULL)
1164 if ((l2 = l2->next) == NULL)
1171 return g_list_sort_merge (g_list_sort_real (list, compare_func, user_data),
1172 g_list_sort_real (l2, compare_func, user_data),
1179 * @list: a #GList, this must point to the top of the list
1180 * @compare_func: the comparison function used to sort the #GList.
1181 * This function is passed the data from 2 elements of the #GList
1182 * and should return 0 if they are equal, a negative value if the
1183 * first element comes before the second, or a positive value if
1184 * the first element comes after the second.
1186 * Sorts a #GList using the given comparison function. The algorithm
1187 * used is a stable sort.
1189 * Returns: the (possibly changed) start of the #GList
1194 * @b: a value to compare with
1196 * Specifies the type of a comparison function used to compare two
1197 * values. The function should return a negative integer if the first
1198 * value comes before the second, 0 if they are equal, or a positive
1199 * integer if the first value comes after the second.
1201 * Returns: negative value if @a < @b; zero if @a = @b; positive
1205 g_list_sort (GList *list,
1206 GCompareFunc compare_func)
1208 return g_list_sort_real (list, (GFunc) compare_func, NULL);
1212 * g_list_sort_with_data:
1213 * @list: a #GList, this must point to the top of the list
1214 * @compare_func: comparison function
1215 * @user_data: user data to pass to comparison function
1217 * Like g_list_sort(), but the comparison function accepts
1218 * a user data argument.
1220 * Returns: the (possibly changed) start of the #GList
1225 * @b: a value to compare with
1226 * @user_data: user data
1228 * Specifies the type of a comparison function used to compare two
1229 * values. The function should return a negative integer if the first
1230 * value comes before the second, 0 if they are equal, or a positive
1231 * integer if the first value comes after the second.
1233 * Returns: negative value if @a < @b; zero if @a = @b; positive
1237 g_list_sort_with_data (GList *list,
1238 GCompareDataFunc compare_func,
1241 return g_list_sort_real (list, (GFunc) compare_func, user_data);