/* $NetBSD: queue.h,v 1.70 2015/11/02 15:21:23 christos Exp $ */
/*
* 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 _SYS_QUEUE_H_
#define _SYS_QUEUE_H_
/*
* This file defines five types of data structures: singly-linked lists,
* lists, simple queues, tail queues, and circular queues.
*
* A singly-linked list is headed by a single forward pointer. The
* elements are singly linked for minimum space and pointer manipulation
* overhead at the expense of O(n) removal for arbitrary elements. New
* elements can be added to the list after an existing element or at the
* head of the list. Elements being removed from the head of the list
* should use the explicit macro for this purpose for optimum
* efficiency. A singly-linked list may only be traversed in the forward
* direction. Singly-linked lists are ideal for applications with large
* datasets and few or no removals or for implementing a LIFO queue.
*
* A list is headed by a single forward pointer (or an array of forward
* pointers for a hash table header). 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 or at the head of the list. A list
* may only be traversed in the forward direction.
*
* A simple queue is headed by a pair of pointers, one the head of the
* list and the other to the tail of the list. The elements are singly
* linked to save space, so elements can only be removed from the
* head of the list. New elements can be added to the list after
* an existing element, at the head of the list, or at the end of the
* list. A simple queue may only be traversed in the forward direction.
*
* 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.
*
* A circle 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 circle queue may be traversed in either direction, but has a more
* complex end of list detection.
*
* For details on the use of these macros, see the queue(3) manual page.
*/
/*
* Include the definition of NULL only on NetBSD because sys/null.h
* is not available elsewhere. This conditional makes the header
* portable and it can simply be dropped verbatim into any system.
* The caveat is that on other systems some other header
* must provide NULL before the macros can be used.
*/
#ifdef __NetBSD__
#include <sys/null.h>
#endif
#if defined(QUEUEDEBUG)
# if defined(_KERNEL)
# define QUEUEDEBUG_ABORT(...) panic(__VA_ARGS__)
# else
# include <err.h>
# define QUEUEDEBUG_ABORT(...) err(1, __VA_ARGS__)
# endif
#endif
/*
* Singly-linked List definitions.
*/
#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 access methods.
*/
#define SLIST_FIRST(head) ((head)->slh_first)
#define SLIST_END(head) NULL
#define SLIST_EMPTY(head) ((head)->slh_first == NULL)
#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
#define SLIST_FOREACH(var, head, field) \
for((var) = (head)->slh_first; \
(var) != SLIST_END(head); \
(var) = (var)->field.sle_next)
#define SLIST_FOREACH_SAFE(var, head, field, tvar) \
for ((var) = SLIST_FIRST((head)); \
(var) != SLIST_END(head) && \
((tvar) = SLIST_NEXT((var), field), 1); \
(var) = (tvar))
/*
* Singly-linked List functions.
*/
#define SLIST_INIT(head) do { \
(head)->slh_first = SLIST_END(head); \
} while (/*CONSTCOND*/0)
#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
(elm)->field.sle_next = (slistelm)->field.sle_next; \
(slistelm)->field.sle_next = (elm); \
} while (/*CONSTCOND*/0)
#define SLIST_INSERT_HEAD(head, elm, field) do { \
(elm)->field.sle_next = (head)->slh_first; \
(head)->slh_first = (elm); \
} while (/*CONSTCOND*/0)
#define SLIST_REMOVE_AFTER(slistelm, field) do { \
(slistelm)->field.sle_next = \
SLIST_NEXT(SLIST_NEXT((slistelm), field), field); \
} while (/*CONSTCOND*/0)
#define SLIST_REMOVE_HEAD(head, field) do { \
(head)->slh_first = (head)->slh_first->field.sle_next; \
} while (/*CONSTCOND*/0)
#define SLIST_REMOVE(head, elm, type, field) do { \
if ((head)->slh_first == (elm)) { \
SLIST_REMOVE_HEAD((head), field); \
} \
else { \
struct type *curelm = (head)->slh_first; \
while(curelm->field.sle_next != (elm)) \
curelm = curelm->field.sle_next; \
curelm->field.sle_next = \
curelm->field.sle_next->field.sle_next; \
} \
} while (/*CONSTCOND*/0)
/*
* List definitions.
*/
#define LIST_HEAD(name, type) \
struct name { \
struct type *lh_first; /* first element */ \
}
#define LIST_HEAD_INITIALIZER(head) \
{ NULL }
#define LIST_ENTRY(type) \
struct { \
struct type *le_next; /* next element */ \
struct type **le_prev; /* address of previous next element */ \
}
/*
* List access methods.
*/
#define LIST_FIRST(head) ((head)->lh_first)
#define LIST_END(head) NULL
#define LIST_EMPTY(head) ((head)->lh_first == LIST_END(head))
#define LIST_NEXT(elm, field) ((elm)->field.le_next)
#define LIST_FOREACH(var, head, field) \
for ((var) = ((head)->lh_first); \
(var) != LIST_END(head); \
(var) = ((var)->field.le_next))
#define LIST_FOREACH_SAFE(var, head, field, tvar) \
for ((var) = LIST_FIRST((head)); \
(var) != LIST_END(head) && \
((tvar) = LIST_NEXT((var), field), 1); \
(var) = (tvar))
#define LIST_MOVE(head1, head2) do { \
LIST_INIT((head2)); \
if (!LIST_EMPTY((head1))) { \
(head2)->lh_first = (head1)->lh_first; \
LIST_INIT((head1)); \
} \
} while (/*CONSTCOND*/0)
/*
* List functions.
*/
#if defined(QUEUEDEBUG)
#define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field) \
if ((head)->lh_first && \
(head)->lh_first->field.le_prev != &(head)->lh_first) \
QUEUEDEBUG_ABORT("LIST_INSERT_HEAD %p %s:%d", (head), \
__FILE__, __LINE__);
#define QUEUEDEBUG_LIST_OP(elm, field) \
if ((elm)->field.le_next && \
(elm)->field.le_next->field.le_prev != \
&(elm)->field.le_next) \
QUEUEDEBUG_ABORT("LIST_* forw %p %s:%d", (elm), \
__FILE__, __LINE__); \
if (*(elm)->field.le_prev != (elm)) \
QUEUEDEBUG_ABORT("LIST_* back %p %s:%d", (elm), \
__FILE__, __LINE__);
#define QUEUEDEBUG_LIST_POSTREMOVE(elm, field) \
(elm)->field.le_next = (void *)1L; \
(elm)->field.le_prev = (void *)1L;
#else
#define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field)
#define QUEUEDEBUG_LIST_OP(elm, field)
#define QUEUEDEBUG_LIST_POSTREMOVE(elm, field)
#endif
#define LIST_INIT(head) do { \
(head)->lh_first = LIST_END(head); \
} while (/*CONSTCOND*/0)
#define LIST_INSERT_AFTER(listelm, elm, field) do { \
QUEUEDEBUG_LIST_OP((listelm), field) \
if (((elm)->field.le_next = (listelm)->field.le_next) != \
LIST_END(head)) \
(listelm)->field.le_next->field.le_prev = \
&(elm)->field.le_next; \
(listelm)->field.le_next = (elm); \
(elm)->field.le_prev = &(listelm)->field.le_next; \
} while (/*CONSTCOND*/0)
#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
QUEUEDEBUG_LIST_OP((listelm), field) \
(elm)->field.le_prev = (listelm)->field.le_prev; \
(elm)->field.le_next = (listelm); \
*(listelm)->field.le_prev = (elm); \
(listelm)->field.le_prev = &(elm)->field.le_next; \
} while (/*CONSTCOND*/0)
#define LIST_INSERT_HEAD(head, elm, field) do { \
QUEUEDEBUG_LIST_INSERT_HEAD((head), (elm), field) \
if (((elm)->field.le_next = (head)->lh_first) != LIST_END(head))\
(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
(head)->lh_first = (elm); \
(elm)->field.le_prev = &(head)->lh_first; \
} while (/*CONSTCOND*/0)
#define LIST_REMOVE(elm, field) do { \
QUEUEDEBUG_LIST_OP((elm), field) \
if ((elm)->field.le_next != NULL) \
(elm)->field.le_next->field.le_prev = \
(elm)->field.le_prev; \
*(elm)->field.le_prev = (elm)->field.le_next; \
QUEUEDEBUG_LIST_POSTREMOVE((elm), field) \
} while (/*CONSTCOND*/0)
#define LIST_REPLACE(elm, elm2, field) do { \
if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \
(elm2)->field.le_next->field.le_prev = \
&(elm2)->field.le_next; \
(elm2)->field.le_prev = (elm)->field.le_prev; \
*(elm2)->field.le_prev = (elm2); \
QUEUEDEBUG_LIST_POSTREMOVE((elm), field) \
} while (/*CONSTCOND*/0)
/*
* Simple queue definitions.
*/
#define SIMPLEQ_HEAD(name, type) \
struct name { \
struct type *sqh_first; /* first element */ \
struct type **sqh_last; /* addr of last next element */ \
}
#define SIMPLEQ_HEAD_INITIALIZER(head) \
{ NULL, &(head).sqh_first }
#define SIMPLEQ_ENTRY(type) \
struct { \
struct type *sqe_next; /* next element */ \
}
/*
* Simple queue access methods.
*/
#define SIMPLEQ_FIRST(head) ((head)->sqh_first)
#define SIMPLEQ_END(head) NULL
#define SIMPLEQ_EMPTY(head) ((head)->sqh_first == SIMPLEQ_END(head))
#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
#define SIMPLEQ_FOREACH(var, head, field) \
for ((var) = ((head)->sqh_first); \
(var) != SIMPLEQ_END(head); \
(var) = ((var)->field.sqe_next))
#define SIMPLEQ_FOREACH_SAFE(var, head, field, next) \
for ((var) = ((head)->sqh_first); \
(var) != SIMPLEQ_END(head) && \
((next = ((var)->field.sqe_next)), 1); \
(var) = (next))
/*
* Simple queue functions.
*/
#define SIMPLEQ_INIT(head) do { \
(head)->sqh_first = NULL; \
(head)->sqh_last = &(head)->sqh_first; \
} while (/*CONSTCOND*/0)
#define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \
if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
(head)->sqh_last = &(elm)->field.sqe_next; \
(head)->sqh_first = (elm); \
} while (/*CONSTCOND*/0)
#define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \
(elm)->field.sqe_next = NULL; \
*(head)->sqh_last = (elm); \
(head)->sqh_last = &(elm)->field.sqe_next; \
} while (/*CONSTCOND*/0)
#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
(head)->sqh_last = &(elm)->field.sqe_next; \
(listelm)->field.sqe_next = (elm); \
} while (/*CONSTCOND*/0)
#define SIMPLEQ_REMOVE_HEAD(head, field) do { \
if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
(head)->sqh_last = &(head)->sqh_first; \
} while (/*CONSTCOND*/0)
#define SIMPLEQ_REMOVE_AFTER(head, elm, field) do { \
if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \
== NULL) \
(head)->sqh_last = &(elm)->field.sqe_next; \
} while (/*CONSTCOND*/0)
#define SIMPLEQ_REMOVE(head, elm, type, field) do { \
if ((head)->sqh_first == (elm)) { \
SIMPLEQ_REMOVE_HEAD((head), field); \
} else { \
struct type *curelm = (head)->sqh_first; \
while (curelm->field.sqe_next != (elm)) \
curelm = curelm->field.sqe_next; \
if ((curelm->field.sqe_next = \
curelm->field.sqe_next->field.sqe_next) == NULL) \
(head)->sqh_last = &(curelm)->field.sqe_next; \
} \
} while (/*CONSTCOND*/0)
#define SIMPLEQ_CONCAT(head1, head2) do { \
if (!SIMPLEQ_EMPTY((head2))) { \
*(head1)->sqh_last = (head2)->sqh_first; \
(head1)->sqh_last = (head2)->sqh_last; \
SIMPLEQ_INIT((head2)); \
} \
} while (/*CONSTCOND*/0)
#define SIMPLEQ_LAST(head, type, field) \
(SIMPLEQ_EMPTY((head)) ? \
NULL : \
((struct type *)(void *) \
((char *)((head)->sqh_last) - offsetof(struct type, field))))
/*
* Tail queue definitions.
*/
#define _TAILQ_HEAD(name, type, qual) \
struct name { \
qual type *tqh_first; /* first element */ \
qual type *qual *tqh_last; /* addr of last next element */ \
}
#define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type,)
#define TAILQ_HEAD_INITIALIZER(head) \
{ TAILQ_END(head), &(head).tqh_first }
#define _TAILQ_ENTRY(type, qual) \
struct { \
qual type *tqe_next; /* next element */ \
qual type *qual *tqe_prev; /* address of previous next element */\
}
#define TAILQ_ENTRY(type) _TAILQ_ENTRY(struct type,)
/*
* Tail queue access methods.
*/
#define TAILQ_FIRST(head) ((head)->tqh_first)
#define TAILQ_END(head) (NULL)
#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
#define TAILQ_LAST(head, headname) \
(*(((struct headname *)(void *)((head)->tqh_last))->tqh_last))
#define TAILQ_PREV(elm, headname, field) \
(*(((struct headname *)(void *)((elm)->field.tqe_prev))->tqh_last))
#define TAILQ_EMPTY(head) (TAILQ_FIRST(head) == TAILQ_END(head))
#define TAILQ_FOREACH(var, head, field) \
for ((var) = ((head)->tqh_first); \
(var) != TAILQ_END(head); \
(var) = ((var)->field.tqe_next))
#define TAILQ_FOREACH_SAFE(var, head, field, next) \
for ((var) = ((head)->tqh_first); \
(var) != TAILQ_END(head) && \
((next) = TAILQ_NEXT(var, field), 1); (var) = (next))
#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
for ((var) = TAILQ_LAST((head), headname); \
(var) != TAILQ_END(head); \
(var) = TAILQ_PREV((var), headname, field))
#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, prev) \
for ((var) = TAILQ_LAST((head), headname); \
(var) != TAILQ_END(head) && \
((prev) = TAILQ_PREV((var), headname, field), 1); (var) = (prev))
/*
* Tail queue functions.
*/
#if defined(QUEUEDEBUG)
#define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field) \
if ((head)->tqh_first && \
(head)->tqh_first->field.tqe_prev != &(head)->tqh_first) \
QUEUEDEBUG_ABORT("TAILQ_INSERT_HEAD %p %s:%d", (head), \
__FILE__, __LINE__);
#define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field) \
if (*(head)->tqh_last != NULL) \
QUEUEDEBUG_ABORT("TAILQ_INSERT_TAIL %p %s:%d", (head), \
__FILE__, __LINE__);
#define QUEUEDEBUG_TAILQ_OP(elm, field) \
if ((elm)->field.tqe_next && \
(elm)->field.tqe_next->field.tqe_prev != \
&(elm)->field.tqe_next) \
QUEUEDEBUG_ABORT("TAILQ_* forw %p %s:%d", (elm), \
__FILE__, __LINE__); \
if (*(elm)->field.tqe_prev != (elm)) \
QUEUEDEBUG_ABORT("TAILQ_* back %p %s:%d", (elm), \
__FILE__, __LINE__);
#define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field) \
if ((elm)->field.tqe_next == NULL && \
(head)->tqh_last != &(elm)->field.tqe_next) \
QUEUEDEBUG_ABORT("TAILQ_PREREMOVE head %p elm %p %s:%d",\
(head), (elm), __FILE__, __LINE__);
#define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field) \
(elm)->field.tqe_next = (void *)1L; \
(elm)->field.tqe_prev = (void *)1L;
#else
#define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field)
#define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field)
#define QUEUEDEBUG_TAILQ_OP(elm, field)
#define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field)
#define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field)
#endif
#define TAILQ_INIT(head) do { \
(head)->tqh_first = TAILQ_END(head); \
(head)->tqh_last = &(head)->tqh_first; \
} while (/*CONSTCOND*/0)
#define TAILQ_INSERT_HEAD(head, elm, field) do { \
QUEUEDEBUG_TAILQ_INSERT_HEAD((head), (elm), field) \
if (((elm)->field.tqe_next = (head)->tqh_first) != TAILQ_END(head))\
(head)->tqh_first->field.tqe_prev = \
&(elm)->field.tqe_next; \
else \
(head)->tqh_last = &(elm)->field.tqe_next; \
(head)->tqh_first = (elm); \
(elm)->field.tqe_prev = &(head)->tqh_first; \
} while (/*CONSTCOND*/0)
#define TAILQ_INSERT_TAIL(head, elm, field) do { \
QUEUEDEBUG_TAILQ_INSERT_TAIL((head), (elm), field) \
(elm)->field.tqe_next = TAILQ_END(head); \
(elm)->field.tqe_prev = (head)->tqh_last; \
*(head)->tqh_last = (elm); \
(head)->tqh_last = &(elm)->field.tqe_next; \
} while (/*CONSTCOND*/0)
#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
QUEUEDEBUG_TAILQ_OP((listelm), field) \
if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != \
TAILQ_END(head)) \
(elm)->field.tqe_next->field.tqe_prev = \
&(elm)->field.tqe_next; \
else \
(head)->tqh_last = &(elm)->field.tqe_next; \
(listelm)->field.tqe_next = (elm); \
(elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
} while (/*CONSTCOND*/0)
#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
QUEUEDEBUG_TAILQ_OP((listelm), field) \
(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
(elm)->field.tqe_next = (listelm); \
*(listelm)->field.tqe_prev = (elm); \
(listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
} while (/*CONSTCOND*/0)
#define TAILQ_REMOVE(head, elm, field) do { \
QUEUEDEBUG_TAILQ_PREREMOVE((head), (elm), field) \
QUEUEDEBUG_TAILQ_OP((elm), field) \
if (((elm)->field.tqe_next) != TAILQ_END(head)) \
(elm)->field.tqe_next->field.tqe_prev = \
(elm)->field.tqe_prev; \
else \
(head)->tqh_last = (elm)->field.tqe_prev; \
*(elm)->field.tqe_prev = (elm)->field.tqe_next; \
QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field); \
} while (/*CONSTCOND*/0)
#define TAILQ_REPLACE(head, elm, elm2, field) do { \
if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != \
TAILQ_END(head)) \
(elm2)->field.tqe_next->field.tqe_prev = \
&(elm2)->field.tqe_next; \
else \
(head)->tqh_last = &(elm2)->field.tqe_next; \
(elm2)->field.tqe_prev = (elm)->field.tqe_prev; \
*(elm2)->field.tqe_prev = (elm2); \
QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field); \
} while (/*CONSTCOND*/0)
#define TAILQ_CONCAT(head1, head2, field) do { \
if (!TAILQ_EMPTY(head2)) { \
*(head1)->tqh_last = (head2)->tqh_first; \
(head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
(head1)->tqh_last = (head2)->tqh_last; \
TAILQ_INIT((head2)); \
} \
} while (/*CONSTCOND*/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 access methods.
*/
#define STAILQ_FIRST(head) ((head)->stqh_first)
#define STAILQ_END(head) NULL
#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
#define STAILQ_EMPTY(head) (STAILQ_FIRST(head) == STAILQ_END(head))
/*
* Singly-linked Tail queue functions.
*/
#define STAILQ_INIT(head) do { \
(head)->stqh_first = NULL; \
(head)->stqh_last = &(head)->stqh_first; \
} while (/*CONSTCOND*/0)
#define STAILQ_INSERT_HEAD(head, elm, field) do { \
if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \
(head)->stqh_last = &(elm)->field.stqe_next; \
(head)->stqh_first = (elm); \
} while (/*CONSTCOND*/0)
#define STAILQ_INSERT_TAIL(head, elm, field) do { \
(elm)->field.stqe_next = NULL; \
*(head)->stqh_last = (elm); \
(head)->stqh_last = &(elm)->field.stqe_next; \
} while (/*CONSTCOND*/0)
#define STAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\
(head)->stqh_last = &(elm)->field.stqe_next; \
(listelm)->field.stqe_next = (elm); \
} while (/*CONSTCOND*/0)
#define STAILQ_REMOVE_HEAD(head, field) do { \
if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \
(head)->stqh_last = &(head)->stqh_first; \
} while (/*CONSTCOND*/0)
#define STAILQ_REMOVE(head, elm, type, field) do { \
if ((head)->stqh_first == (elm)) { \
STAILQ_REMOVE_HEAD((head), field); \
} else { \
struct type *curelm = (head)->stqh_first; \
while (curelm->field.stqe_next != (elm)) \
curelm = curelm->field.stqe_next; \
if ((curelm->field.stqe_next = \
curelm->field.stqe_next->field.stqe_next) == NULL) \
(head)->stqh_last = &(curelm)->field.stqe_next; \
} \
} while (/*CONSTCOND*/0)
#define STAILQ_FOREACH(var, head, field) \
for ((var) = ((head)->stqh_first); \
(var); \
(var) = ((var)->field.stqe_next))
#define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
for ((var) = STAILQ_FIRST((head)); \
(var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
(var) = (tvar))
#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 (/*CONSTCOND*/0)
#define STAILQ_LAST(head, type, field) \
(STAILQ_EMPTY((head)) ? \
NULL : \
((struct type *)(void *) \
((char *)((head)->stqh_last) - offsetof(struct type, field))))
#ifndef _KERNEL
/*
* Circular queue definitions. Do not use. We still keep the macros
* for compatibility but because of pointer aliasing issues their use
* is discouraged!
*/
/*
* __launder_type(): We use this ugly hack to work around the the compiler
* noticing that two types may not alias each other and elide tests in code.
* We hit this in the CIRCLEQ macros when comparing 'struct name *' and
* 'struct type *' (see CIRCLEQ_HEAD()). Modern compilers (such as GCC
* 4.8) declare these comparisons as always false, causing the code to
* not run as designed.
*
* This hack is only to be used for comparisons and thus can be fully const.
* Do not use for assignment.
*
* If we ever choose to change the ABI of the CIRCLEQ macros, we could fix
* this by changing the head/tail sentinal values, but see the note above
* this one.
*/
static __inline const void * __launder_type(const void *);
static __inline const void *
__launder_type(const void *__x)
{
__asm __volatile("" : "+r" (__x));
return __x;
}
#if defined(QUEUEDEBUG)
#define QUEUEDEBUG_CIRCLEQ_HEAD(head, field) \
if ((head)->cqh_first != CIRCLEQ_ENDC(head) && \
(head)->cqh_first->field.cqe_prev != CIRCLEQ_ENDC(head)) \
QUEUEDEBUG_ABORT("CIRCLEQ head forw %p %s:%d", (head), \
__FILE__, __LINE__); \
if ((head)->cqh_last != CIRCLEQ_ENDC(head) && \
(head)->cqh_last->field.cqe_next != CIRCLEQ_ENDC(head)) \
QUEUEDEBUG_ABORT("CIRCLEQ head back %p %s:%d", (head), \
__FILE__, __LINE__);
#define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field) \
if ((elm)->field.cqe_next == CIRCLEQ_ENDC(head)) { \
if ((head)->cqh_last != (elm)) \
QUEUEDEBUG_ABORT("CIRCLEQ elm last %p %s:%d", \
(elm), __FILE__, __LINE__); \
} else { \
if ((elm)->field.cqe_next->field.cqe_prev != (elm)) \
QUEUEDEBUG_ABORT("CIRCLEQ elm forw %p %s:%d", \
(elm), __FILE__, __LINE__); \
} \
if ((elm)->field.cqe_prev == CIRCLEQ_ENDC(head)) { \
if ((head)->cqh_first != (elm)) \
QUEUEDEBUG_ABORT("CIRCLEQ elm first %p %s:%d", \
(elm), __FILE__, __LINE__); \
} else { \
if ((elm)->field.cqe_prev->field.cqe_next != (elm)) \
QUEUEDEBUG_ABORT("CIRCLEQ elm prev %p %s:%d", \
(elm), __FILE__, __LINE__); \
}
#define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field) \
(elm)->field.cqe_next = (void *)1L; \
(elm)->field.cqe_prev = (void *)1L;
#else
#define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)
#define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)
#define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field)
#endif
#define CIRCLEQ_HEAD(name, type) \
struct name { \
struct type *cqh_first; /* first element */ \
struct type *cqh_last; /* last element */ \
}
#define CIRCLEQ_HEAD_INITIALIZER(head) \
{ CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
#define CIRCLEQ_ENTRY(type) \
struct { \
struct type *cqe_next; /* next element */ \
struct type *cqe_prev; /* previous element */ \
}
/*
* Circular queue functions.
*/
#define CIRCLEQ_INIT(head) do { \
(head)->cqh_first = CIRCLEQ_END(head); \
(head)->cqh_last = CIRCLEQ_END(head); \
} while (/*CONSTCOND*/0)
#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
QUEUEDEBUG_CIRCLEQ_HEAD((head), field) \
QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field) \
(elm)->field.cqe_next = (listelm)->field.cqe_next; \
(elm)->field.cqe_prev = (listelm); \
if ((listelm)->field.cqe_next == CIRCLEQ_ENDC(head)) \
(head)->cqh_last = (elm); \
else \
(listelm)->field.cqe_next->field.cqe_prev = (elm); \
(listelm)->field.cqe_next = (elm); \
} while (/*CONSTCOND*/0)
#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
QUEUEDEBUG_CIRCLEQ_HEAD((head), field) \
QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field) \
(elm)->field.cqe_next = (listelm); \
(elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
if ((listelm)->field.cqe_prev == CIRCLEQ_ENDC(head)) \
(head)->cqh_first = (elm); \
else \
(listelm)->field.cqe_prev->field.cqe_next = (elm); \
(listelm)->field.cqe_prev = (elm); \
} while (/*CONSTCOND*/0)
#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
QUEUEDEBUG_CIRCLEQ_HEAD((head), field) \
(elm)->field.cqe_next = (head)->cqh_first; \
(elm)->field.cqe_prev = CIRCLEQ_END(head); \
if ((head)->cqh_last == CIRCLEQ_ENDC(head)) \
(head)->cqh_last = (elm); \
else \
(head)->cqh_first->field.cqe_prev = (elm); \
(head)->cqh_first = (elm); \
} while (/*CONSTCOND*/0)
#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
QUEUEDEBUG_CIRCLEQ_HEAD((head), field) \
(elm)->field.cqe_next = CIRCLEQ_END(head); \
(elm)->field.cqe_prev = (head)->cqh_last; \
if ((head)->cqh_first == CIRCLEQ_ENDC(head)) \
(head)->cqh_first = (elm); \
else \
(head)->cqh_last->field.cqe_next = (elm); \
(head)->cqh_last = (elm); \
} while (/*CONSTCOND*/0)
#define CIRCLEQ_REMOVE(head, elm, field) do { \
QUEUEDEBUG_CIRCLEQ_HEAD((head), field) \
QUEUEDEBUG_CIRCLEQ_ELM((head), (elm), field) \
if ((elm)->field.cqe_next == CIRCLEQ_ENDC(head)) \
(head)->cqh_last = (elm)->field.cqe_prev; \
else \
(elm)->field.cqe_next->field.cqe_prev = \
(elm)->field.cqe_prev; \
if ((elm)->field.cqe_prev == CIRCLEQ_ENDC(head)) \
(head)->cqh_first = (elm)->field.cqe_next; \
else \
(elm)->field.cqe_prev->field.cqe_next = \
(elm)->field.cqe_next; \
QUEUEDEBUG_CIRCLEQ_POSTREMOVE((elm), field) \
} while (/*CONSTCOND*/0)
#define CIRCLEQ_FOREACH(var, head, field) \
for ((var) = ((head)->cqh_first); \
(var) != CIRCLEQ_ENDC(head); \
(var) = ((var)->field.cqe_next))
#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
for ((var) = ((head)->cqh_last); \
(var) != CIRCLEQ_ENDC(head); \
(var) = ((var)->field.cqe_prev))
/*
* Circular queue access methods.
*/
#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
#define CIRCLEQ_LAST(head) ((head)->cqh_last)
/* For comparisons */
#define CIRCLEQ_ENDC(head) (__launder_type(head))
/* For assignments */
#define CIRCLEQ_END(head) ((void *)(head))
#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
#define CIRCLEQ_EMPTY(head) \
(CIRCLEQ_FIRST(head) == CIRCLEQ_ENDC(head))
#define CIRCLEQ_LOOP_NEXT(head, elm, field) \
(((elm)->field.cqe_next == CIRCLEQ_ENDC(head)) \
? ((head)->cqh_first) \
: (elm->field.cqe_next))
#define CIRCLEQ_LOOP_PREV(head, elm, field) \
(((elm)->field.cqe_prev == CIRCLEQ_ENDC(head)) \
? ((head)->cqh_last) \
: (elm->field.cqe_prev))
#endif /* !_KERNEL */
#endif /* !_SYS_QUEUE_H_ */
