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+/* Generic linked list
+ * Copyright (C) 1997, 2000 Kunihiro Ishiguro
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef _ZEBRA_LINKLIST_H
+#define _ZEBRA_LINKLIST_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* listnodes must always contain data to be valid. Adding an empty node
+ * to a list is invalid
+ */
+struct listnode {
+ struct listnode *next;
+ struct listnode *prev;
+
+ /* private member, use getdata() to retrieve, do not access directly */
+ void *data;
+};
+
+struct list {
+ struct listnode *head;
+ struct listnode *tail;
+
+ /* invariant: count is the number of listnodes in the list */
+ unsigned int count;
+
+ uint8_t flags;
+/* Indicates that listnode memory is managed by the application and
+ * doesn't need to be freed by this library via listnode_delete etc.
+ */
+#define LINKLIST_FLAG_NODE_MEM_BY_APP (1 << 0)
+
+ /*
+ * Returns -1 if val1 < val2, 0 if equal?, 1 if val1 > val2.
+ * Used as definition of sorted for listnode_add_sort
+ */
+ int (*cmp)(void *val1, void *val2);
+
+ /* callback to free user-owned data when listnode is deleted. supplying
+ * this callback is very much encouraged!
+ */
+ void (*del)(void *val);
+};
+
+#define listnextnode(X) ((X) ? ((X)->next) : NULL)
+#define listnextnode_unchecked(X) ((X)->next)
+#define listhead(X) ((X) ? ((X)->head) : NULL)
+#define listhead_unchecked(X) ((X)->head)
+#define listtail(X) ((X) ? ((X)->tail) : NULL)
+#define listtail_unchecked(X) ((X)->tail)
+#define listcount(X) ((X)->count)
+#define list_isempty(X) ((X)->head == NULL && (X)->tail == NULL)
+/* return X->data only if X and X->data are not NULL */
+#define listgetdata(X) (assert(X), assert((X)->data != NULL), (X)->data)
+/* App is going to manage listnode memory */
+#define listset_app_node_mem(X) ((X)->flags |= LINKLIST_FLAG_NODE_MEM_BY_APP)
+#define listnode_init(X, val) ((X)->data = (val))
+
+/*
+ * Create a new linked list.
+ *
+ * Returns:
+ * the created linked list
+ */
+extern struct list *list_new(void);
+
+/*
+ * Add a new element to the tail of a list.
+ *
+ * Runtime is O(1).
+ *
+ * list
+ * list to operate on
+ *
+ * data
+ * element to add
+ */
+extern struct listnode *listnode_add(struct list *list, void *data);
+
+/*
+ * Add a new element to the beginning of a list.
+ *
+ * Runtime is O(1).
+ *
+ * list
+ * list to operate on
+ *
+ * data
+ * If MEM_BY_APP is set this is listnode. Otherwise it is element to add.
+ */
+extern void listnode_add_head(struct list *list, void *data);
+
+/*
+ * Insert a new element into a list with insertion sort.
+ *
+ * If list->cmp is set, this function is used to determine the position to
+ * insert the new element. If it is not set, this function is equivalent to
+ * listnode_add.
+ *
+ * Runtime is O(N).
+ *
+ * list
+ * list to operate on
+ *
+ * val
+ * If MEM_BY_APP is set this is listnode. Otherwise it is element to add.
+ */
+extern void listnode_add_sort(struct list *list, void *val);
+
+/*
+ * Insert a new element into a list after another element.
+ *
+ * Runtime is O(1).
+ *
+ * list
+ * list to operate on
+ *
+ * pp
+ * listnode to insert after
+ *
+ * data
+ * If MEM_BY_APP is set this is listnode. Otherwise it is element to add.
+ *
+ * Returns:
+ * pointer to newly created listnode that contains the inserted data
+ */
+extern struct listnode *listnode_add_after(struct list *list,
+ struct listnode *pp, void *data);
+
+/*
+ * Insert a new element into a list before another element.
+ *
+ * Runtime is O(1).
+ *
+ * list
+ * list to operate on
+ *
+ * pp
+ * listnode to insert before
+ *
+ * data
+ * If MEM_BY_APP is set this is listnode. Otherwise it is element to add.
+ *
+ * Returns:
+ * pointer to newly created listnode that contains the inserted data
+ */
+extern struct listnode *listnode_add_before(struct list *list,
+ struct listnode *pp, void *data);
+
+/*
+ * Move a node to the tail of a list.
+ *
+ * Runtime is O(1).
+ *
+ * list
+ * list to operate on
+ *
+ * node
+ * node to move to tail
+ */
+extern void listnode_move_to_tail(struct list *list, struct listnode *node);
+
+/*
+ * Delete an element from a list.
+ *
+ * Runtime is O(N).
+ *
+ * list
+ * list to operate on
+ *
+ * data
+ * data to insert into list
+ */
+extern void listnode_delete(struct list *list, const void *data);
+
+/*
+ * Find the listnode corresponding to an element in a list.
+ *
+ * list
+ * list to operate on
+ *
+ * data
+ * data to search for
+ *
+ * Returns:
+ * pointer to listnode storing the given data if found, NULL otherwise
+ */
+extern struct listnode *listnode_lookup(struct list *list, const void *data);
+
+/*
+ * Retrieve the element at the head of a list.
+ *
+ * list
+ * list to operate on
+ *
+ * Returns:
+ * data at head of list, or NULL if list is empty
+ */
+extern void *listnode_head(struct list *list);
+
+/*
+ * Sort a list in place.
+ *
+ * The sorting algorithm used is quicksort. Runtimes are equivalent to those of
+ * quicksort plus N. The sort is not stable.
+ *
+ * For portability reasons, the comparison function takes a pointer to pointer
+ * to void. This pointer should be dereferenced to get the actual data pointer.
+ * It is always safe to do this.
+ *
+ * list
+ * list to sort
+ *
+ * cmp
+ * comparison function for quicksort. Should return less than, equal to or
+ * greater than zero if the first argument is less than, equal to or greater
+ * than the second argument.
+ */
+extern void list_sort(struct list *list,
+ int (*cmp)(const void **, const void **));
+
+/*
+ * Convert a list to an array of void pointers.
+ *
+ * Starts from the list head and ends either on the last node of the list or
+ * when the provided array cannot store any more elements.
+ *
+ * list
+ * list to convert
+ *
+ * arr
+ * Pre-allocated array of void *
+ *
+ * arrlen
+ * Number of elements in arr
+ *
+ * Returns:
+ * arr
+ */
+void **list_to_array(struct list *list, void **arr, size_t arrlen);
+
+/*
+ * Delete a list and NULL its pointer.
+ *
+ * If non-null, list->del is called with each data element.
+ *
+ * plist
+ * pointer to list pointer; this will be set to NULL after the list has been
+ * deleted
+ */
+extern void list_delete(struct list **plist);
+
+/*
+ * Delete all nodes from a list without deleting the list itself.
+ *
+ * If non-null, list->del is called with each data element.
+ *
+ * list
+ * list to operate on
+ */
+extern void list_delete_all_node(struct list *list);
+
+/*
+ * Delete a node from a list.
+ *
+ * list->del is not called with the data associated with the node.
+ *
+ * Runtime is O(1).
+ *
+ * list
+ * list to operate on
+ *
+ * node
+ * the node to delete
+ */
+extern void list_delete_node(struct list *list, struct listnode *node);
+
+/*
+ * Insert a new element into a list with insertion sort if there is no
+ * duplicate element present in the list. This assumes the input list is
+ * sorted. If unsorted, it will check for duplicate until it finds out
+ * the position to do insertion sort with the unsorted list.
+ *
+ * If list->cmp is set, this function is used to determine the position to
+ * insert the new element. If it is not set, this function is equivalent to
+ * listnode_add. duplicate element is determined by cmp function returning 0.
+ *
+ * Runtime is O(N).
+ *
+ * list
+ * list to operate on
+ *
+ * val
+ * If MEM_BY_APP is set this is listnode. Otherwise it is element to add.
+ */
+
+extern bool listnode_add_sort_nodup(struct list *list, void *val);
+
+/*
+ * Duplicate the specified list, creating a shallow copy of each of its
+ * elements.
+ *
+ * list
+ * list to duplicate
+ *
+ * Returns:
+ * the duplicated list
+ */
+extern struct list *list_dup(struct list *list);
+
+/* List iteration macro.
+ * Usage: for (ALL_LIST_ELEMENTS (...) { ... }
+ * It is safe to delete the listnode using this macro.
+ */
+#define ALL_LIST_ELEMENTS(list, node, nextnode, data) \
+ (node) = listhead(list), ((data) = NULL); \
+ (node) != NULL \
+ && ((data) = static_cast(data, listgetdata(node)), \
+ (nextnode) = node->next, 1); \
+ (node) = (nextnode), ((data) = NULL)
+
+/* read-only list iteration macro.
+ * Usage: as per ALL_LIST_ELEMENTS, but not safe to delete the listnode Only
+ * use this macro when it is *immediately obvious* the listnode is not
+ * deleted in the body of the loop. Does not have forward-reference overhead
+ * of previous macro.
+ */
+#define ALL_LIST_ELEMENTS_RO(list, node, data) \
+ (node) = listhead(list), ((data) = NULL); \
+ (node) != NULL && ((data) = static_cast(data, listgetdata(node)), 1); \
+ (node) = listnextnode(node), ((data) = NULL)
+
+extern struct listnode *listnode_lookup_nocheck(struct list *list, void *data);
+
+/*
+ * Add a node to *list, if non-NULL. Otherwise, allocate a new list, mail
+ * it back in *list, and add a new node.
+ *
+ * Return: the new node.
+ */
+extern struct listnode *listnode_add_force(struct list **list, void *val);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _ZEBRA_LINKLIST_H */