queue.h

/*
 * Copyright (C) Igor Sysoev
 */

#pragma once

typedef struct queue_s {
    struct queue_s *prev;
    struct queue_s  *next;
} queue_t;

#define queue_init(q)                                                     \
    (q)->prev = q;                                                            \
    (q)->next = q


#define queue_empty(h)                                                    \
    (h == (h)->prev)


#define queue_insert_head(h, x)                                           \
    (x)->next = (h)->next;                                                    \
    (x)->next->prev = x;                                                      \
    (x)->prev = h;                                                            \
    (h)->next = x


#define queue_insert_after   queue_insert_head


#define queue_insert_tail(h, x)                                           \
    (x)->prev = (h)->prev;                                                    \
    (x)->prev->next = x;                                                      \
    (x)->next = h;                                                            \
    (h)->prev = x


#define queue_head(h)                                                     \
    (h)->next


#define queue_last(h)                                                     \
    (h)->prev


#define queue_sentinel(h)                                                 \
    (h)


#define queue_next(q)                                                     \
    (q)->next


#define queue_prev(q)                                                     \
    (q)->prev


#define queue_remove(x)                                                   \
    (x)->next->prev = (x)->prev;                                              \
    (x)->prev->next = (x)->next


#define queue_split(h, q, n)                                              \
    (n)->prev = (h)->prev;                                                    \
    (n)->prev->next = n;                                                      \
    (n)->next = q;                                                            \
    (h)->prev = (q)->prev;                                                    \
    (h)->prev->next = h;                                                      \
    (q)->prev = n;


#define queue_add(h, n)                                                   \
    (h)->prev->next = (n)->next;                                              \
    (n)->next->prev = (h)->prev;                                              \
    (h)->prev = (n)->prev;                                                    \
    (h)->prev->next = h;


#define queue_data(q, type, link)                                         \
    (type *) ((unsigned char *) q - offsetof(type, link))


#define queue_foreach(q, h)                                               \
    for ((q) = queue_head(h); (q) != (h); (q) = queue_next(q))