frr/lib/linklist.h
Anuradha Karuppiah 5c733b883d lib: allow listnode memory to be managed by the app
In most cases this memory is pre-allocated along with the base element.
Similarly it is stored in the base element to allow efficient del
without lookup (main reason for using DLL vs. SLL).

So (in most cases) there should be no need to manage the element/data
and listnode memories separately.

Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
2020-08-05 06:46:12 -07:00

398 lines
11 KiB
C

/* 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);
/*
* Delete all nodes which satisfy a condition from a list.
* Deletes the node if cond function returns true for the node.
* If function ptr passed is NULL, it deletes all nodes
*
* list
* list to operate on
* cond
* function pointer which takes node data as input and return true or false
*/
extern void list_filter_out_nodes(struct list *list, bool (*cond)(void *data));
/*
* 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);
/* 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)
/* these *do not* cleanup list nodes and referenced data, as the functions
* do - these macros simply {de,at}tach a listnode from/to a list.
*/
/* List node attach macro. */
#define LISTNODE_ATTACH(L, N) \
do { \
(N)->prev = (L)->tail; \
(N)->next = NULL; \
if ((L)->head == NULL) \
(L)->head = (N); \
else \
(L)->tail->next = (N); \
(L)->tail = (N); \
(L)->count++; \
} while (0)
/* List node detach macro. */
#define LISTNODE_DETACH(L, N) \
do { \
if ((N)->prev) \
(N)->prev->next = (N)->next; \
else \
(L)->head = (N)->next; \
if ((N)->next) \
(N)->next->prev = (N)->prev; \
else \
(L)->tail = (N)->prev; \
(L)->count--; \
} while (0)
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 */