list.h

#ifndef LIST_H
#define LIST_H

#include <stddef.h>

#define container_of(ptr, type, member)                                       \
  ((type *)((void *)(ptr) - offsetof (type, member)))

#define attr_nonnull(...) __attribute__ ((nonnull (__VA_ARGS__)))

typedef struct list_t list_t;
typedef struct list_node_t list_node_t;

struct list_node_t
{
  list_node_t *prev;
  list_node_t *next;
};

struct list_t
{
  size_t size;
  list_node_t *head;
  list_node_t *tail;
};

#define LIST_INIT                                                             \
  (list_t) {}

extern list_node_t *list_at (const list_t *list, size_t index)
    attr_nonnull (1);

extern void list_push_front (list_t *list, list_node_t *node)
    attr_nonnull (1, 2);

extern void list_push_back (list_t *list, list_node_t *node)
    attr_nonnull (1, 2);

extern void list_insert_at (list_t *list, size_t index, list_node_t *node)
    attr_nonnull (1, 3);

extern void list_insert_front (list_t *list, list_node_t *pos,
                               list_node_t *node) attr_nonnull (1, 2, 3);

extern void list_insert_back (list_t *list, list_node_t *pos,
                              list_node_t *node) attr_nonnull (1, 2, 3);

extern void list_erase (list_t *list, list_node_t *node) attr_nonnull (1, 2);

extern void list_erase_at (list_t *list, size_t index) attr_nonnull (1);

extern void list_pop_front (list_t *list) attr_nonnull (1);

extern void list_pop_back (list_t *list) attr_nonnull (1);

/* **************************************************************** */
/*                               ext                                */
/* **************************************************************** */

typedef void list_visit_t (list_node_t *n);

typedef int list_comp_t (const list_node_t *a, const list_node_t *b);

extern list_node_t *list_find (const list_t *list, const list_node_t *target,
                               list_comp_t *comp) attr_nonnull (1, 2, 3);

extern void list_visit (list_t *list, list_visit_t *visit) attr_nonnull (1, 2);

#endif