list.h

#pragma once

#include <stdbool.h>
#include <stddef.h>

#ifndef container_of
#ifdef __HAVE_TYPEOF
#define container_of(ptr, type, member)                            \
    __extension__({                                                \
        const __typeof__(((type *) 0)->member) *__pmember = (ptr); \
        (type *) ((char *) __pmember - offsetof(type, member));    \
    })
#else
#define container_of(ptr, type, member) \
    ((type *) ((char *) (ptr) - (offsetof(type, member))))
#endif
#endif

struct hlist_head {
    struct hlist_node *first;
};

struct hlist_node {
    struct hlist_node *next, **pprev;
};

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

static inline void INIT_HLIST_NODE(struct hlist_node *h)
{
    h->next = NULL;
    h->pprev = NULL;
}

static inline int hlist_empty(const struct hlist_head *h)
{
    return !h->first;
}

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 bool hlist_unhashed(const struct hlist_node *h)
{
    return !h->pprev;
}

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_init(struct hlist_node *n)
{
    if (hlist_unhashed(n))
        return;
    hlist_del(n);
    INIT_HLIST_NODE(n);
}

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

#ifdef __HAVE_TYPEOF
#define hlist_entry_safe(ptr, type, member)                  \
    ({                                                       \
        typeof(ptr) ____ptr = (ptr);                         \
        ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
    })
#else
#define hlist_entry_safe(ptr, type, member) \
    (ptr) ? hlist_entry(ptr, type, member) : NULL
#endif

#ifdef __HAVE_TYPEOF
#define hlist_for_each_entry(pos, head, member)                              \
    for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member); pos; \
         pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
#else
#define hlist_for_each_entry(pos, head, member, type)              \
    for (pos = hlist_entry_safe((head)->first, type, member); pos; \
         pos = hlist_entry_safe((pos)->member.next, type, member))
#endif