/* SPDX-License-Identifier: GPL-2.0 */
#ifndef LIST_H
#define LIST_H

/*
 * Copied from include/linux/...
 */

#undef offsetof
#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE*)0)->MEMBER)

/**
 * container_of - cast a member of a structure out to the containing structure
 * @ptr:        the pointer to the member.
 * @type:       the type of the container struct this is embedded in.
 * @member:     the name of the member within the struct.
 *
 */
#define container_of(ptr, type, member)                                                                                        \
    ({                                                                                                                         \
        const typeof(((type*)0)->member)* __mptr = (ptr);                                                                      \
        (type*)((char*)__mptr - offsetof(type, member));                                                                       \
    })

struct list_head {
    struct list_head *next, *prev;
};

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

#define LIST_HEAD(name) struct list_head name = LIST_HEAD_INIT(name)

#define INIT_LIST_HEAD(name)                                                                                                   \
    do {                                                                                                                       \
        (name)->next = (name)->prev = (name);                                                                                  \
    } while (0)

/**
 * 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_head within the struct.
 */
#define list_entry(ptr, type, member) container_of(ptr, type, member)

/**
 * list_for_each_entry	-	iterate over list of given type
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_head 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_safe - iterate over list of given type safe against removal of list entry
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_head within the struct.
 */
#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))

/**
 * 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; }

/*
 * 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_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;
}

#define LIST_POISON1 ((void*)0x00100100)
#define LIST_POISON2 ((void*)0x00200200)
/**
 * 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_del(struct list_head* entry)
{
    __list_del(entry->prev, entry->next);
    entry->next = (struct list_head*)LIST_POISON1;
    entry->prev = (struct list_head*)LIST_POISON2;
}
#endif
