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 2.1 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->prev 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, but does not update links from the next and
190 * previous elements in the list, so you should not call this function on an
191 * element that is currently part of a list.
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 * This iterates over the list until it reaches the @n-th position. If you
737 * intend to iterate over every element, it is better to use a for-loop as
738 * described in the #GList introduction.
740 * Returns: the element, or %NULL if the position is off
741 * the end of the #GList
744 g_list_nth (GList
*list
,
747 while ((n
-- > 0) && list
)
756 * @n: the position of the element, counting from 0
758 * Gets the element @n places before @list.
760 * Returns: the element, or %NULL if the position is
761 * off the end of the #GList
764 g_list_nth_prev (GList
*list
,
767 while ((n
-- > 0) && list
)
775 * @list: a #GList, this must point to the top of the list
776 * @n: the position of the element
778 * Gets the data of the element at the given position.
780 * This iterates over the list until it reaches the @n-th position. If you
781 * intend to iterate over every element, it is better to use a for-loop as
782 * described in the #GList introduction.
784 * Returns: the element's data, or %NULL if the position
785 * is off the end of the #GList
788 g_list_nth_data (GList
*list
,
791 while ((n
-- > 0) && list
)
794 return list
? list
->data
: NULL
;
799 * @list: a #GList, this must point to the top of the list
800 * @data: the element data to find
802 * Finds the element in a #GList which contains the given data.
804 * Returns: the found #GList element, or %NULL if it is not found
807 g_list_find (GList
*list
,
812 if (list
->data
== data
)
821 * g_list_find_custom:
822 * @list: a #GList, this must point to the top of the list
823 * @data: user data passed to the function
824 * @func: the function to call for each element.
825 * It should return 0 when the desired element is found
827 * Finds an element in a #GList, using a supplied function to
828 * find the desired element. It iterates over the list, calling
829 * the given function which should return 0 when the desired
830 * element is found. The function takes two #gconstpointer arguments,
831 * the #GList element's data as the first argument and the
834 * Returns: the found #GList element, or %NULL if it is not found
837 g_list_find_custom (GList
*list
,
841 g_return_val_if_fail (func
!= NULL
, list
);
845 if (! func (list
->data
, data
))
855 * @list: a #GList, this must point to the top of the list
856 * @llink: an element in the #GList
858 * Gets the position of the given element
859 * in the #GList (starting from 0).
861 * Returns: the position of the element in the #GList,
862 * or -1 if the element is not found
865 g_list_position (GList
*list
,
884 * @list: a #GList, this must point to the top of the list
885 * @data: the data to find
887 * Gets the position of the element containing
888 * the given data (starting from 0).
890 * Returns: the index of the element containing the data,
891 * or -1 if the data is not found
894 g_list_index (GList
*list
,
902 if (list
->data
== data
)
913 * @list: any #GList element
915 * Gets the last element in a #GList.
917 * Returns: the last element in the #GList,
918 * or %NULL if the #GList has no elements
921 g_list_last (GList
*list
)
934 * @list: any #GList element
936 * Gets the first element in a #GList.
938 * Returns: the first element in the #GList,
939 * or %NULL if the #GList has no elements
942 g_list_first (GList
*list
)
955 * @list: a #GList, this must point to the top of the list
957 * Gets the number of elements in a #GList.
959 * This function iterates over the whole list to count its elements.
960 * Use a #GQueue instead of a GList if you regularly need the number
961 * of items. To check whether the list is non-empty, it is faster to check
962 * @list against %NULL.
964 * Returns: the number of elements in the #GList
967 g_list_length (GList
*list
)
983 * @list: a #GList, this must point to the top of the list
984 * @func: the function to call with each element's data
985 * @user_data: user data to pass to the function
987 * Calls a function for each element of a #GList.
991 * @data: the element's data
992 * @user_data: user data passed to g_list_foreach() or g_slist_foreach()
994 * Specifies the type of functions passed to g_list_foreach() and
998 g_list_foreach (GList
*list
,
1004 GList
*next
= list
->next
;
1005 (*func
) (list
->data
, user_data
);
1011 g_list_insert_sorted_real (GList
*list
,
1016 GList
*tmp_list
= list
;
1020 g_return_val_if_fail (func
!= NULL
, list
);
1024 new_list
= _g_list_alloc0 ();
1025 new_list
->data
= data
;
1029 cmp
= ((GCompareDataFunc
) func
) (data
, tmp_list
->data
, user_data
);
1031 while ((tmp_list
->next
) && (cmp
> 0))
1033 tmp_list
= tmp_list
->next
;
1035 cmp
= ((GCompareDataFunc
) func
) (data
, tmp_list
->data
, user_data
);
1038 new_list
= _g_list_alloc0 ();
1039 new_list
->data
= data
;
1041 if ((!tmp_list
->next
) && (cmp
> 0))
1043 tmp_list
->next
= new_list
;
1044 new_list
->prev
= tmp_list
;
1050 tmp_list
->prev
->next
= new_list
;
1051 new_list
->prev
= tmp_list
->prev
;
1053 new_list
->next
= tmp_list
;
1054 tmp_list
->prev
= new_list
;
1056 if (tmp_list
== list
)
1063 * g_list_insert_sorted:
1064 * @list: a pointer to a #GList, this must point to the top of the
1065 * already sorted list
1066 * @data: the data for the new element
1067 * @func: the function to compare elements in the list. It should
1068 * return a number > 0 if the first parameter comes after the
1069 * second parameter in the sort order.
1071 * Inserts a new element into the list, using the given comparison
1072 * function to determine its position.
1074 * If you are adding many new elements to a list, and the number of
1075 * new elements is much larger than the length of the list, use
1076 * g_list_prepend() to add the new items and sort the list afterwards
1077 * 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
1092 * already sorted list
1093 * @data: the data for the new element
1094 * @func: the function to compare elements in the list. It should
1095 * return a number > 0 if the first parameter comes after the
1096 * second parameter in the sort order.
1097 * @user_data: user data to pass to comparison function
1099 * Inserts a new element into the list, using the given comparison
1100 * function to determine its position.
1102 * If you are adding many new elements to a list, and the number of
1103 * new elements is much larger than the length of the list, use
1104 * g_list_prepend() to add the new items and sort the list afterwards
1105 * with g_list_sort().
1107 * Returns: the (possibly changed) start of the #GList
1112 g_list_insert_sorted_with_data (GList
*list
,
1114 GCompareDataFunc func
,
1117 return g_list_insert_sorted_real (list
, data
, (GFunc
) func
, user_data
);
1121 g_list_sort_merge (GList
*l1
,
1126 GList list
, *l
, *lprev
;
1134 cmp
= ((GCompareDataFunc
) compare_func
) (l1
->data
, l2
->data
, user_data
);
1150 l
->next
= l1
? l1
: l2
;
1157 g_list_sort_real (GList
*list
,
1171 while ((l2
= l2
->next
) != NULL
)
1173 if ((l2
= l2
->next
) == NULL
)
1180 return g_list_sort_merge (g_list_sort_real (list
, compare_func
, user_data
),
1181 g_list_sort_real (l2
, compare_func
, user_data
),
1188 * @list: a #GList, this must point to the top of the list
1189 * @compare_func: the comparison function used to sort the #GList.
1190 * This function is passed the data from 2 elements of the #GList
1191 * and should return 0 if they are equal, a negative value if the
1192 * first element comes before the second, or a positive value if
1193 * the first element comes after the second.
1195 * Sorts a #GList using the given comparison function. The algorithm
1196 * used is a stable sort.
1198 * Returns: the (possibly changed) start of the #GList
1203 * @b: a value to compare with
1205 * Specifies the type of a comparison function used to compare two
1206 * values. The function should return a negative integer if the first
1207 * value comes before the second, 0 if they are equal, or a positive
1208 * integer if the first value comes after the second.
1210 * Returns: negative value if @a < @b; zero if @a = @b; positive
1214 g_list_sort (GList
*list
,
1215 GCompareFunc compare_func
)
1217 return g_list_sort_real (list
, (GFunc
) compare_func
, NULL
);
1221 * g_list_sort_with_data:
1222 * @list: a #GList, this must point to the top of the list
1223 * @compare_func: comparison function
1224 * @user_data: user data to pass to comparison function
1226 * Like g_list_sort(), but the comparison function accepts
1227 * a user data argument.
1229 * Returns: the (possibly changed) start of the #GList
1234 * @b: a value to compare with
1235 * @user_data: user data
1237 * Specifies the type of a comparison function used to compare two
1238 * values. The function should return a negative integer if the first
1239 * value comes before the second, 0 if they are equal, or a positive
1240 * integer if the first value comes after the second.
1242 * Returns: negative value if @a < @b; zero if @a = @b; positive
1246 g_list_sort_with_data (GList
*list
,
1247 GCompareDataFunc compare_func
,
1250 return g_list_sort_real (list
, (GFunc
) compare_func
, user_data
);