/*

 * Soft:        Keepalived is a failover program for the LVS project

 *              <www.linuxvirtualserver.org>. It monitor & manipulate

 *              a loadbalanced server pool using multi-layer checks.

 *		In addition it provides a VRRPv2 & VRRPv3 stack.

 *

 * Author:      Alexandre Cassen, <acassen@corp.free.fr>

 *

 *              This program 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.

 *

 *              This program 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 of the License, or (at your option) any later version.

 *

 * Copyright (C) 2018 Alexandre Cassen, <acassen@corp.free.fr>

 */

#ifndef _LIST_HEAD_H

#define _LIST_HEAD_H

#include <stdlib.h>

#include <stddef.h>

#include "container.h"

/*

 * These are non-NULL pointers that will result in page faults

 * under normal circumstances, used to verify that nobody uses

 * non-initialized list entries.

 */

#define LIST_POISON1  ((void *) 0x00100100)

#define LIST_POISON2  ((void *) 0x00200200)

/*

 * Simple doubly linked list implementation.

 *

 * Some of the internal functions ("__xxx") are useful when

 * manipulating whole lists rather than single entries, as

 * sometimes we already know the next/prev entries and we can

 * generate better code by using them directly rather than

 * using the generic single-entry routines.

 */

typedef struct list_head {

	struct list_head *next, *prev;

} list_head_t;

/* Simple initializer */

#define LIST_HEAD_INITIALIZER(name) { &(name), &(name) }

#define LIST_HEAD_INITIALIZE(name) \

	list_head_t name = LIST_HEAD_INITIALIZER(name)

#define INIT_LIST_HEAD(ptr) do { \

	(ptr)->next = (ptr); (ptr)->prev = (ptr); \

} while (0)

/*

 * Insert a new entry between two known consecutive entries.

 *

 * This is only for internal list manipulation where we know

 * the prev/next entries already!

 */

static inline void __list_add(struct list_head *new,

			      struct list_head *prev,

			      struct list_head *next)

{

	next->prev = new;

	new->next = next;

	new->prev = prev;

	prev->next = new;

}

/**

 * list_head_add - add a new entry

 * @new: new entry to be added

 * @head: list head to add it after

 *

 * Insert a new entry after the specified head.

 * This is good for implementing stacks.

 */

static inline void list_head_add(struct list_head *new, struct list_head *head)

{

	__list_add(new, head, head->next);

}

// list_head_add_tail

/**

 * list_add_tail - add a new entry

 * @new: new entry to be added

 * @head: list head to add it before

 *

 * Insert a new entry before the specified head.

 * This is useful for implementing queues.

 */

static inline void list_add_tail(struct list_head *new, struct list_head *head)

{

	__list_add(new, head->prev, head);

}

/*

 * Delete a list entry by making the prev/next entries

 * point to each other.

 *

 * This is only for internal list manipulation where we know

 * the prev/next entries already!

 */

static inline void __list_del(struct list_head * prev, struct list_head * next)

{

	next->prev = prev;

	prev->next = next;

}

/**

 * list_del - deletes entry from list.

 * @entry: the element to delete from the list.

 * Note: list_empty on entry does not return true after this, the entry is

 * in an undefined state.

 */

static inline void list_head_del(struct list_head *entry)

{

	__list_del(entry->prev, entry->next);

	entry->next = LIST_POISON1;

	entry->prev = LIST_POISON2;

}

/**

 * list_del_init - deletes entry from list and reinitialize it.

 * @entry: the element to delete from the list.

 */

static inline void list_del_init(struct list_head *entry)

{

	__list_del(entry->prev, entry->next);

	INIT_LIST_HEAD(entry);

}

/**

 * list_move - delete from one list and add as another's head

 * @lst: the entry to move

 * @head: the head that will precede our entry

 */

static inline void list_move(struct list_head *lst, struct list_head *head)

{

	__list_del(lst->prev, lst->next);

	list_head_add(lst, head);

}

/**

 * list_move_tail - delete from one list and add as another's tail

 * @lst: the entry to move

 * @head: the head that will follow our entry

 */

static inline void list_move_tail(struct list_head *lst,

				  struct list_head *head)

{

	__list_del(lst->prev, lst->next);

	list_add_tail(lst, head);

}

/**

 * list_is_first - tests whether @list is the first entry in list @head

 * @lst: the entry to test

 * @head: the head of the list

 */

static inline int list_is_first(const struct list_head *lst,

				const struct list_head *head)

{

	return lst->prev == head;

}

/**

 * list_is_last - tests whether @list is the last entry in list @head

 * @lst: the entry to test

 * @head: the head of the list

 */

static inline int list_is_last(const struct list_head *lst,

			       const struct list_head *head)

{

	return lst->next == head;

}

/**

 * list_empty - tests whether a list is empty

 * @head: the list to test.

 */

static inline int list_empty(const struct list_head *head)

{

	return head->next == head;

}

/**

 * list_copy - copy one list to another

 * @dst: the destination list

 * @src: the source list

 */

static inline void list_copy(struct list_head *dst, struct list_head *src)

{

	if (list_empty(src))

		INIT_LIST_HEAD(dst);

	else {

		*dst = *src;

		dst->next->prev = dst;

		dst->prev->next = dst;

	}

}

static inline void __list_splice(struct list_head *lst,

				 struct list_head *head)

{

	struct list_head *first = lst->next;

	struct list_head *last = lst->prev;

	struct list_head *at = head->next;

	first->prev = head;

	head->next = first;

	last->next = at;

	at->prev = last;

}

/**

 * list_splice - join two lists

 * @lst: the new list to add.

 * @head: the place to add it in the first list.

 */

static inline void list_splice(struct list_head *lst, struct list_head *head)

{

	if (!list_empty(lst))

		__list_splice(lst, head);

}

/**

 * list_splice_init - join two lists and reinitialise the emptied list.

 * @list: the new list to add.

 * @head: the place to add it in the first list.

 *

 * The list at @list is reinitialised

 */

static inline void list_splice_init(struct list_head *lst,

				    struct list_head *head)

{

	if (!list_empty(lst)) {

		__list_splice(lst, head);

		INIT_LIST_HEAD(lst);

	}

}

/**

 * list_sort - merge sort elements of a list.

 * @head: the head of the list.

 * @cmp: the function used to compare to list nodes.

 */

void list_sort(struct list_head *head,

	       int (*cmp)(struct list_head *a, struct list_head *b));

/**

 * list_entry - get the struct for this entry

 * @ptr:	the &struct list_head pointer.

 * @type:	the type of the struct this is embedded in.

 * @member:	the name of the list_struct within the struct.

 */

#define list_entry(ptr, type, member) \

	container_of(ptr, type, member)

/**

 * list_first_entry - get the first element from a list

 * @ptr:	the list head to take the element from.

 * @type:	the type of the struct this is embedded in.

 * @member:	the name of the list_struct within the struct.

 *

 * Note, that list is expected to be not empty.

 */

#define list_first_entry(ptr, type, member) \

	list_entry((ptr)->next, type, member)

/**

 * list_last_entry - get the last element from a list

 * @ptr:	the list head to take the element from.

 * @type:	the type of the struct this is embedded in.

 * @member:	the name of the list_struct within the struct.

 *

 * Note, that list is expected to be not empty.

 */

#define list_last_entry(ptr, type, member) \

	list_entry((ptr)->prev, type, member)

/**

 * list_for_each	-	iterate over a list

 * @pos:	the &struct list_head to use as a loop counter.

 * @head:	the head for your list.

 */

#define list_for_each(pos, head) \

	for (pos = (head)->next; pos != (head); \

		pos = pos->next)

// __list_for_each isn't different

/**

 * __list_for_each	-	iterate over a list

 * @pos:	the &struct list_head to use as a loop counter.

 * @head:	the head for your list.

 *

 * This variant differs from list_for_each() in that it's the

 * simplest possible list iteration code, no prefetching is done.

 * Use this for code that knows the list to be very short (empty

 * or 1 entry) most of the time.

 */

#define __list_for_each(pos, head) \

	for (pos = (head)->next; pos != (head); pos = pos->next)

/**

 * list_for_each_prev	-	iterate over a list backwards

 * @pos:	the &struct list_head to use as a loop counter.

 * @head:	the head for your list.

 */

#define list_for_each_prev(pos, head) \

	for (pos = (head)->prev; pos != (head); \

		pos = pos->prev)

/**

 * list_for_each_safe	-	iterate over a list safe against removal of list entry

 * @pos:	the &struct list_head to use as a loop counter.

 * @n:		another &struct list_head to use as temporary storage

 * @head:	the head for your list.

 */

#define list_for_each_safe(pos, n, head) \

	for (pos = (head)->next, n = pos->next; pos != (head); \

		pos = n, n = pos->next)

/**

 * list_for_each_entry	-	iterate over list of given type

 * @pos:	the type * to use as a loop counter.

 * @head:	the head for your list.

 * @member:	the name of the list_struct within the struct.

 */

#define list_for_each_entry(pos, head, member)				\

	for (pos = list_entry((head)->next, typeof(*pos), member);	\

	     &pos->member != (head);					\

	     pos = list_entry(pos->member.next, typeof(*pos), member))

/**

 * list_for_each_entry_reverse - iterate backwards over list of given type.

 * @pos:	the type * to use as a loop counter.

 * @head:	the head for your list.

 * @member:	the name of the list_struct within the struct.

 */

#define list_for_each_entry_reverse(pos, head, member)			\

	for (pos = list_entry((head)->prev, typeof(*pos), member);	\

	     &pos->member != (head);					\

	     pos = list_entry(pos->member.prev, typeof(*pos), member))

/**

 * list_for_each_entry_continue -	iterate over list of given type

 *			continuing after existing point

 * @pos:	the type * to use as a loop counter.

 * @head:	the head for your list.

 * @member:	the name of the list_struct within the struct.

 */

#define list_for_each_entry_continue(pos, head, member)			\

	for (pos = list_entry(pos->member.next, typeof(*pos), member);	\

	     &pos->member != (head);					\

	     pos = list_entry(pos->member.next, typeof(*pos), member))

/**

 * list_for_each_entry_continue_reverse - iterate backwards from the given point

 * @pos:	the type * to use as a loop cursor.

 * @head:	the head for your list.

 * @member:	the name of the list_struct within the struct.

 *

 * Start to iterate over list of given type backwards, continuing after

 * the current position.

 */

#define list_for_each_entry_continue_reverse(pos, head, member)		\

	for (pos = list_entry(pos->member.prev, typeof(*pos), member);	\

	     &pos->member != (head);					\

	     pos = list_entry(pos->member.prev, typeof(*pos), member))

/**

 * list_for_each_entry_from - iterate over list of given type from the current point

 * @pos:	the type * to use as a loop cursor.

 * @head:	the head for your list.

 * @member:	the name of the list_struct within the struct.

 *

 * Iterate over list of given type, continuing from current position.

 */

#define list_for_each_entry_from(pos, head, member)			\

	for (; &pos->member != (head);					\

	     pos = list_entry(pos->member.next, typeof(*pos), member))

/**

 * list_for_each_entry_from - iterate over list of given type from the current point

 * @pos:	the type * to use as a loop cursor.

 * @head:	the head for your list.

 * @member:	the name of the list_struct within the struct.

 *

 * Iterate over list of given type, continuing from current position.

 */

#define list_for_each_entry_from_reverse(pos, head, member)		\

	for (; &pos->member != (head);					\

	     pos = list_entry(pos->member.prev, typeof(*pos), member))

/**

 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry

 * @pos:	the type * to use as a loop counter.

 * @n:		another type * to use as temporary storage

 * @head:	the head for your list.

 * @member:	the name of the list_struct within the struct.

 */

// Try the alternative

#define list_for_each_entry_safe(pos, n, head, member)			\

	for (pos = list_entry((head)->next, typeof(*pos), member),	\

		n = list_entry(pos->member.next, typeof(*pos), member);	\

	     &pos->member != (head);					\

	     pos = n, n = list_entry(n->member.next, typeof(*n), member))

/*

 * Double linked lists with a single pointer list head.

 * Mostly useful for hash tables where the two pointer list head is

 * too wasteful.

 * You lose the ability to access the tail in O(1).

 */

typedef struct hlist_head {

	struct hlist_node *first;

} hlist_head_t;

typedef struct hlist_node {

	struct hlist_node *next, **pprev;

} hlist_node_t;

#define HLIST_HEAD_INITIALIZER { .first = NULL }

#define HLIST_HEAD_INITIALIZE(name) \

	hlist_head_t name = { .first = NULL }

#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)

#define INIT_HLIST_NODE(ptr) ((ptr)->next = NULL, (ptr)->pprev = NULL)

static __inline__ int hlist_unhashed(const struct hlist_node *h)

{

	return !h->pprev;

}

static __inline__ int hlist_empty(const struct hlist_head *h)

{

	return !h->first;

}

static __inline__ void __hlist_del(struct hlist_node *n)

{

	struct hlist_node *next = n->next;

	struct hlist_node **pprev = n->pprev;

	*pprev = next;

	if (next)

		next->pprev = pprev;

}

static __inline__ void hlist_del(struct hlist_node *n)

{

	__hlist_del(n);

	n->next = LIST_POISON1;

	n->pprev = LIST_POISON2;

}

static __inline__ void hlist_del_init(struct hlist_node *n)

{

	if (n->pprev)  {

		__hlist_del(n);

		INIT_HLIST_NODE(n);

	}

}

static __inline__ void hlist_add_head(struct hlist_node *n, struct hlist_head *h)

{

	struct hlist_node *first = h->first;

	n->next = first;

	if (first)

		first->pprev = &n->next;

	h->first = n;

	n->pprev = &h->first;

}

static __inline__ void hlist_add_before(struct hlist_node *n, struct hlist_node *next)

{

	n->pprev = next->pprev;

	n->next = next;

	next->pprev = &n->next;

	*(n->pprev) = n;

}

static __inline__ void hlist_add_after(struct hlist_node *n,

				       struct hlist_node *next)

{

	next->next = n->next;

	n->next = next;

	next->pprev = &n->next;

	if (next->next)

		next->next->pprev = &next->next;

}

#define hlist_entry(ptr, type, member) container_of(ptr,type,member)

#define hlist_for_each(pos, head) \

	for (pos = (head)->first; pos; pos = pos->next)

#define hlist_for_each_safe(pos, n, head) \

	for (pos = (head)->first; n = pos ? pos->next : 0, pos; \

	     pos = n)

/**

 * hlist_for_each_entry	- iterate over list of given type

 * @tpos:	the type * to use as a loop counter.

 * @pos:	the &struct hlist_node to use as a loop counter.

 * @head:	the head for your list.

 * @member:	the name of the hlist_node within the struct.

 */

#define hlist_for_each_entry(tpos, pos, head, member)			 \

	for (pos = (head)->first;					 \

	     pos &&							 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \

	     pos = pos->next)

/**

 * hlist_for_each_entry_continue - iterate over a hlist continuing after existing point

 * @tpos:	the type * to use as a loop counter.

 * @pos:	the &struct hlist_node to use as a loop counter.

 * @member:	the name of the hlist_node within the struct.

 */

#define hlist_for_each_entry_continue(tpos, pos, member)		 \

	for (pos = (pos)->next;						 \

	     pos &&							 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \

	     pos = pos->next)

/**

 * hlist_for_each_entry_from - iterate over a hlist continuing from existing point

 * @tpos:	the type * to use as a loop counter.

 * @pos:	the &struct hlist_node to use as a loop counter.

 * @member:	the name of the hlist_node within the struct.

 */

#define hlist_for_each_entry_from(tpos, pos, member)			 \

	for (; pos &&							 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \

	     pos = pos->next)

/**

 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry

 * @tpos:	the type * to use as a loop counter.

 * @pos:	the &struct hlist_node to use as a loop counter.

 * @n:		another &struct hlist_node to use as temporary storage

 * @head:	the head for your list.

 * @member:	the name of the hlist_node within the struct.

 */

#define hlist_for_each_entry_safe(tpos, pos, n, head, member)		 \

	for (pos = (head)->first;					 \

	     pos && ({ n = pos->next; 1; }) &&				 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \

	     pos = n)

#define hlist_insert_sorted(tpos, ntpos, pos, head, smember, hmember, res)	\

	res = 0;								\

	tpos = NULL;								\

	hlist_for_each_entry(tpos, pos, (head), hmember)			\

		if (ntpos->smember <= tpos->smember)				\

			break;							\

	if (tpos) {								\

		if (ntpos->smember < tpos->smember)				\

			hlist_add_before(&ntpos->hmember, &tpos->hmember);	\

		else if (ntpos->smember > tpos->smember)			\

			hlist_add_after(&tpos->hmember, &ntpos->hmember);	\

		else								\

			res = 1;						\

	} else									\

		hlist_add_head(&ntpos->hmember, (head));

#endif /* ! _LIST_HEAD_H */