queue.h

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#ifndef _SYS_QUEUE_H_
#define _SYS_QUEUE_H_

#define QMD_SAVELINK(name, link)
#define TRASHIT(x)

/*
 * Singly-linked List declarations.
 */
#define SLIST_HEAD(name, type)                      \
struct name {                               \
    struct type *slh_first; /* first element */         \
}

#define SLIST_HEAD_INITIALIZER(head)                    \
    { NULL }

#define SLIST_ENTRY(type)                       \
struct {                                \
    struct type *sle_next;  /* next element */          \
}

/*
 * Singly-linked List functions.
 */
#define SLIST_EMPTY(head)   ((head)->slh_first == NULL)

#define SLIST_FIRST(head)   ((head)->slh_first)

#define SLIST_FOREACH(var, head, field)                 \
    for ((var) = SLIST_FIRST((head));               \
        (var);                          \
        (var) = SLIST_NEXT((var), field))

#define SLIST_FOREACH_SAFE(var, head, field, tvar)          \
    for ((var) = SLIST_FIRST((head));               \
        (var) && ((tvar) = SLIST_NEXT((var), field), 1);        \
        (var) = (tvar))

#define SLIST_FOREACH_PREVPTR(var, varp, head, field)           \
    for ((varp) = &SLIST_FIRST((head));             \
        ((var) = *(varp)) != NULL;                  \
        (varp) = &SLIST_NEXT((var), field))

#define SLIST_INIT(head) do {                       \
    SLIST_FIRST((head)) = NULL;                 \
} while (0)

#define SLIST_INSERT_AFTER(slistelm, elm, field) do {           \
    SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);   \
    SLIST_NEXT((slistelm), field) = (elm);              \
} while (0)

#define SLIST_INSERT_HEAD(head, elm, field) do {            \
    SLIST_NEXT((elm), field) = SLIST_FIRST((head));         \
    SLIST_FIRST((head)) = (elm);                    \
} while (0)

#define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)

#define SLIST_REMOVE(head, elm, type, field) do {           \
    QMD_SAVELINK(oldnext, (elm)->field.sle_next);           \
    if (SLIST_FIRST((head)) == (elm)) {             \
        SLIST_REMOVE_HEAD((head), field);           \
    }                               \
    else {                              \
        struct type *curelm = SLIST_FIRST((head));      \
        while (SLIST_NEXT(curelm, field) != (elm))      \
            curelm = SLIST_NEXT(curelm, field);     \
        SLIST_REMOVE_AFTER(curelm, field);          \
    }                               \
    TRASHIT(*oldnext);                      \
} while (0)

#define SLIST_REMOVE_AFTER(elm, field) do {             \
    SLIST_NEXT(elm, field) =                    \
        SLIST_NEXT(SLIST_NEXT(elm, field), field);          \
} while (0)

#define SLIST_REMOVE_HEAD(head, field) do {             \
    SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);   \
} while (0)

/*
 * Singly-linked Tail queue declarations.
 */
#define STAILQ_HEAD(name, type)                     \
    struct name {                               \
        struct type *stqh_first;/* first element */         \
        struct type **stqh_last;/* addr of last next element */     \
    }

#define STAILQ_HEAD_INITIALIZER(head)                   \
    { NULL, &(head).stqh_first }

#define STAILQ_ENTRY(type)                      \
    struct {                                \
        struct type *stqe_next; /* next element */          \
    }

/*
 * Singly-linked Tail queue functions.
 */
#define STAILQ_CONCAT(head1, head2) do {                \
        if (!STAILQ_EMPTY((head2))) {                   \
            *(head1)->stqh_last = (head2)->stqh_first;      \
            (head1)->stqh_last = (head2)->stqh_last;        \
            STAILQ_INIT((head2));                   \
        }                               \
    } while (0)

#define STAILQ_EMPTY(head)  ((head)->stqh_first == NULL)

#define STAILQ_FIRST(head)  ((head)->stqh_first)

#define STAILQ_FOREACH(var, head, field)                \
    for((var) = STAILQ_FIRST((head));               \
            (var);                          \
            (var) = STAILQ_NEXT((var), field))


#define STAILQ_FOREACH_SAFE(var, head, field, tvar)         \
    for ((var) = STAILQ_FIRST((head));              \
            (var) && ((tvar) = STAILQ_NEXT((var), field), 1);       \
            (var) = (tvar))

#define STAILQ_INIT(head) do {                      \
        STAILQ_FIRST((head)) = NULL;                    \
        (head)->stqh_last = &STAILQ_FIRST((head));          \
    } while (0)

#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {       \
        if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
            (head)->stqh_last = &STAILQ_NEXT((elm), field);     \
        STAILQ_NEXT((tqelm), field) = (elm);                \
    } while (0)

#define STAILQ_INSERT_HEAD(head, elm, field) do {           \
        if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
            (head)->stqh_last = &STAILQ_NEXT((elm), field);     \
        STAILQ_FIRST((head)) = (elm);                   \
    } while (0)

#define STAILQ_INSERT_TAIL(head, elm, field) do {           \
        STAILQ_NEXT((elm), field) = NULL;               \
        *(head)->stqh_last = (elm);                 \
        (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
    } while (0)

#define STAILQ_LAST(head, type, field)                  \
    (STAILQ_EMPTY((head)) ?                     \
     NULL :                         \
     ((struct type *)(void *)               \
      ((char *)((head)->stqh_last) - __offsetof(struct type, field))))

#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)

#define STAILQ_REMOVE(head, elm, type, field) do {          \
        QMD_SAVELINK(oldnext, (elm)->field.stqe_next);          \
        if (STAILQ_FIRST((head)) == (elm)) {                \
            STAILQ_REMOVE_HEAD((head), field);          \
        }                               \
        else {                              \
            struct type *curelm = STAILQ_FIRST((head));     \
            while (STAILQ_NEXT(curelm, field) != (elm))     \
                curelm = STAILQ_NEXT(curelm, field);        \
            STAILQ_REMOVE_AFTER(head, curelm, field);       \
        }                               \
        TRASHIT(*oldnext);                      \
    } while (0)

#define STAILQ_REMOVE_HEAD(head, field) do {                \
        if ((STAILQ_FIRST((head)) =                 \
                STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)      \
            (head)->stqh_last = &STAILQ_FIRST((head));      \
    } while (0)

#define STAILQ_REMOVE_AFTER(head, elm, field) do {          \
        if ((STAILQ_NEXT(elm, field) =                  \
                STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL)   \
            (head)->stqh_last = &STAILQ_NEXT((elm), field);     \
    } while (0)

#define STAILQ_SWAP(head1, head2, type) do {                \
        struct type *swap_first = STAILQ_FIRST(head1);          \
        struct type **swap_last = (head1)->stqh_last;           \
        STAILQ_FIRST(head1) = STAILQ_FIRST(head2);          \
        (head1)->stqh_last = (head2)->stqh_last;            \
        STAILQ_FIRST(head2) = swap_first;               \
        (head2)->stqh_last = swap_last;                 \
        if (STAILQ_EMPTY(head1))                    \
            (head1)->stqh_last = &STAILQ_FIRST(head1);      \
        if (STAILQ_EMPTY(head2))                    \
            (head2)->stqh_last = &STAILQ_FIRST(head2);      \
    } while (0)

#define STAILQ_INSERT_CHAIN_HEAD(head, elm_chead, elm_ctail, field) do {   \
        if ((STAILQ_NEXT(elm_ctail, field) = STAILQ_FIRST(head)) == NULL ) { \
            (head)->stqh_last = &STAILQ_NEXT(elm_ctail, field);            \
        }                                                                      \
        STAILQ_FIRST(head) = (elm_chead);                                    \
    } while (0)

#endif /* !_SYS_QUEUE_H_ */