/* $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $ */
/*
* slirp version: Copy from QEMU, removed all but tail queues.
*/
/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)queue.h 8.5 (Berkeley) 8/20/94
*/
#ifndef QTAILQ_H
#define QTAILQ_H
/*
* A tail queue is headed by a pair of pointers, one to the head of the
* list and the other to the tail of the list. The elements are doubly
* linked so that an arbitrary element can be removed without a need to
* traverse the list. New elements can be added to the list before or
* after an existing element, at the head of the list, or at the end of
* the list. A tail queue may be traversed in either direction.
*/
typedef struct QTailQLink {
void *tql_next;
struct QTailQLink *tql_prev;
} QTailQLink;
/*
* Tail queue definitions. The union acts as a poor man template, as if
* it were QTailQLink<type>.
*/
#define QTAILQ_HEAD(name, type) \
union name { \
struct type *tqh_first; /* first element */ \
QTailQLink tqh_circ; /* link for circular backwards list */ \
}
#define QTAILQ_HEAD_INITIALIZER(head) \
{ .tqh_circ = { NULL, &(head).tqh_circ } }
#define QTAILQ_ENTRY(type) \
union { \
struct type *tqe_next; /* next element */ \
QTailQLink tqe_circ; /* link for circular backwards list */ \
}
#define QTAILQ_INIT(head) do { \
(head)->tqh_first = NULL; \
(head)->tqh_circ.tql_prev = &(head)->tqh_circ; \
} while (/*CONSTCOND*/0)
#define QTAILQ_INSERT_HEAD(head, elm, field) do { \
if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
(head)->tqh_first->field.tqe_circ.tql_prev = \
&(elm)->field.tqe_circ; \
else \
(head)->tqh_circ.tql_prev = &(elm)->field.tqe_circ; \
(head)->tqh_first = (elm); \
(elm)->field.tqe_circ.tql_prev = &(head)->tqh_circ; \
} while (/*CONSTCOND*/0)
#define QTAILQ_INSERT_TAIL(head, elm, field) do { \
(elm)->field.tqe_next = NULL; \
(elm)->field.tqe_circ.tql_prev = (head)->tqh_circ.tql_prev; \
(head)->tqh_circ.tql_prev->tql_next = (elm); \
(head)->tqh_circ.tql_prev = &(elm)->field.tqe_circ; \
} while (/*CONSTCOND*/0)
#define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
(elm)->field.tqe_next->field.tqe_circ.tql_prev = \
&(elm)->field.tqe_circ; \
else \
(head)->tqh_circ.tql_prev = &(elm)->field.tqe_circ; \
(listelm)->field.tqe_next = (elm); \
(elm)->field.tqe_circ.tql_prev = &(listelm)->field.tqe_circ; \
} while (/*CONSTCOND*/0)
#define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \
(elm)->field.tqe_circ.tql_prev = (listelm)->field.tqe_circ.tql_prev; \
(elm)->field.tqe_next = (listelm); \
(listelm)->field.tqe_circ.tql_prev->tql_next = (elm); \
(listelm)->field.tqe_circ.tql_prev = &(elm)->field.tqe_circ; \
} while (/*CONSTCOND*/0)
#define QTAILQ_REMOVE(head, elm, field) do { \
if (((elm)->field.tqe_next) != NULL) \
(elm)->field.tqe_next->field.tqe_circ.tql_prev = \
(elm)->field.tqe_circ.tql_prev; \
else \
(head)->tqh_circ.tql_prev = (elm)->field.tqe_circ.tql_prev; \
(elm)->field.tqe_circ.tql_prev->tql_next = (elm)->field.tqe_next; \
(elm)->field.tqe_circ.tql_prev = NULL; \
} while (/*CONSTCOND*/0)
#define QTAILQ_FOREACH(var, head, field) \
for ((var) = ((head)->tqh_first); \
(var); \
(var) = ((var)->field.tqe_next))
#define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \
for ((var) = ((head)->tqh_first); \
(var) && ((next_var) = ((var)->field.tqe_next), 1); \
(var) = (next_var))
#define QTAILQ_FOREACH_REVERSE(var, head, field) \
for ((var) = QTAILQ_LAST(head); \
(var); \
(var) = QTAILQ_PREV(var, field))
#define QTAILQ_FOREACH_REVERSE_SAFE(var, head, field, prev_var) \
for ((var) = QTAILQ_LAST(head); \
(var) && ((prev_var) = QTAILQ_PREV(var, field)); \
(var) = (prev_var))
/*
* Tail queue access methods.
*/
#define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL)
#define QTAILQ_FIRST(head) ((head)->tqh_first)
#define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
#define QTAILQ_IN_USE(elm, field) ((elm)->field.tqe_circ.tql_prev != NULL)
#define QTAILQ_LINK_PREV(link) \
((link).tql_prev->tql_prev->tql_next)
#define QTAILQ_LAST(head) \
((typeof((head)->tqh_first)) QTAILQ_LINK_PREV((head)->tqh_circ))
#define QTAILQ_PREV(elm, field) \
((typeof((elm)->field.tqe_next)) QTAILQ_LINK_PREV((elm)->field.tqe_circ))
#define field_at_offset(base, offset, type) \
((type *) (((char *) (base)) + (offset)))
/*
* Raw access of elements of a tail queue head. Offsets are all zero
* because it's a union.
*/
#define QTAILQ_RAW_FIRST(head) \
field_at_offset(head, 0, void *)
#define QTAILQ_RAW_TQH_CIRC(head) \
field_at_offset(head, 0, QTailQLink)
/*
* Raw access of elements of a tail entry
*/
#define QTAILQ_RAW_NEXT(elm, entry) \
field_at_offset(elm, entry, void *)
#define QTAILQ_RAW_TQE_CIRC(elm, entry) \
field_at_offset(elm, entry, QTailQLink)
/*
* Tail queue traversal using pointer arithmetic.
*/
#define QTAILQ_RAW_FOREACH(elm, head, entry) \
for ((elm) = *QTAILQ_RAW_FIRST(head); \
(elm); \
(elm) = *QTAILQ_RAW_NEXT(elm, entry))
/*
* Tail queue insertion using pointer arithmetic.
*/
#define QTAILQ_RAW_INSERT_TAIL(head, elm, entry) do { \
*QTAILQ_RAW_NEXT(elm, entry) = NULL; \
QTAILQ_RAW_TQE_CIRC(elm, entry)->tql_prev = QTAILQ_RAW_TQH_CIRC(head)->tql_prev; \
QTAILQ_RAW_TQH_CIRC(head)->tql_prev->tql_next = (elm); \
QTAILQ_RAW_TQH_CIRC(head)->tql_prev = QTAILQ_RAW_TQE_CIRC(elm, entry); \
} while (/*CONSTCOND*/0)
#endif /* QTAILQ_H */
