#ifndef Py_INTERNAL_LLIST_H

#define Py_INTERNAL_LLIST_H

#include <stddef.h>

#ifdef __cplusplus

extern "C" {

#ifndef Py_BUILD_CORE

# error "Py_BUILD_CORE must be defined to include this header"

struct llist_node {

struct llist_node *next;

struct llist_node *prev;

};

#define llist_data(node, type, member) (_Py_CONTAINER_OF(node, type, member))

#define llist_for_each(node, head) \

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

#define llist_for_each_safe(node, head) \

for (struct llist_node *_next = (node = (head)->next, node->next); \

node != (head); node = _next, _next = node->next)

#define LLIST_INIT(head) { &head, &head }

static inline void

llist_init(struct llist_node *head)

{

head->next = head;

head->prev = head;

}

static inline int

llist_empty(struct llist_node *head)

{

return head->next == head;

}

static inline void

llist_insert_tail(struct llist_node *head, struct llist_node *node)

{

node->prev = head->prev;

node->next = head;

head->prev->next = node;

head->prev = node;

}

static inline void

llist_remove(struct llist_node *node)

{

struct llist_node *prev = node->prev;

struct llist_node *next = node->next;

prev->next = next;

next->prev = prev;

node->prev = NULL;

node->next = NULL;

}

static inline void

llist_concat(struct llist_node *head1, struct llist_node *head2)

{

if (!llist_empty(head2)) {

head1->prev->next = head2->next;

head2->next->prev = head1->prev;

head1->prev = head2->prev;

head2->prev->next = head1;

llist_init(head2);

}

}

#ifdef __cplusplus

}

#endif /* !Py_INTERNAL_LLIST_H */