#pragma once

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

#define LIST_HEAD(name) \
    struct list_head name = { &name, &name }

#define list_for_each(pos, head) \
    for (pos = (head)->next; pos != (head); pos = pos->next)

#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))

#define list_entry(link, type, member)     ({ \
        const typeof (((type *) 0)->member) *__memb = (link); \
        (type *) ((char *) __memb - offsetof(type, member)); \
    })

#define list_next_entry(pos, member) \
	list_entry((pos)->member.next, typeof(*(pos)), member)

#define list_first_entry(ptr, type, member) \
	list_entry((ptr)->next, type, member)

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

static inline void list_head_init(struct list_head *list) {
	list->next = list;
	list->prev = list;
}

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;
}

static inline void list_add(struct list_head *new, struct list_head *head) {
	__list_add(new, head, head->next);
}

static inline void list_add_tail(struct list_head *new, struct list_head *head) {
	__list_add(new, head->prev, head);
}

static inline void __list_del(struct list_head *prev, struct list_head *next) {
	next->prev = prev;
	prev->next = next;
}

static inline void list_del(struct list_head *entry) {
	__list_del(entry->prev, entry->next);
}

static inline int list_empty(const struct list_head *head) {
	return head->next == head;
}

static inline void list_del_init(struct list_head *entry) {
	__list_del(entry->prev, entry->next);
	list_head_init(entry);
}