[tor-commits] [tor/master] Add a copy of OpenBSD's sys/queue.h as tor_queue.h
andrea at torproject.org
andrea at torproject.org
Tue Oct 30 22:57:38 UTC 2012
commit b555388dac71696c6a1028805094e16b5e5b2b82
Author: Nick Mathewson <nickm at torproject.org>
Date: Fri Oct 12 17:05:06 2012 -0400
Add a copy of OpenBSD's sys/queue.h as tor_queue.h
There are as many divergent implementations of sys/queue.h as there
are operating systems shipping it, it would seem. They have some code
in common, but have drifted apart, and have added other stuff named
differently. So I'm taking a relatively sane one, and hoping for the
best.
I'm taking OpenBSD's in particular because of the lack of external
dependencies, the presence of a CIRCLEQ (we could use one of those in
places), and the liberal licensing terms.
I'm naming the file tor_queue.h, since historically we've run into
trouble having headers with the same names as system headers (log.h,
for example.)
---
LICENSE | 29 +++
changes/bsd_queue | 7 +
src/ext/README | 8 +
src/ext/include.am | 3 +-
src/ext/tor_queue.h | 568 +++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 614 insertions(+), 1 deletions(-)
diff --git a/LICENSE b/LICENSE
index 47eaf97..3058377 100644
--- a/LICENSE
+++ b/LICENSE
@@ -70,6 +70,35 @@ under the following license:
* 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.
+===============================================================================
+src/ext/tor_queue.h is licensed under the following license:
+
+ * 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.
===============================================================================
src/config/geoip is licensed under the following license:
diff --git a/changes/bsd_queue b/changes/bsd_queue
new file mode 100644
index 0000000..024ca6f
--- /dev/null
+++ b/changes/bsd_queue
@@ -0,0 +1,7 @@
+ o Code simplification and refactoring:
+ - Start using OpenBSD's implementation of queue.h, so that we don't
+ need to hand-roll our own pointer and list structures whenever we
+ need them. (We can't rely on a sys/queue.h, since some operating
+ systems don't have them, and the ones that do have them don't all
+ present the same extensions.)
+
diff --git a/src/ext/README b/src/ext/README
index 2c303c1..7aeaba5 100644
--- a/src/ext/README
+++ b/src/ext/README
@@ -29,3 +29,11 @@ tinytest_macros.h
A unit testing framework. https://github.com/nmathewson/tinytest
+tor_queue.h
+
+ A copy of sys/queue.h from OpenBSD. We keep our own copy rather
+ than using sys/queue.h, since some platforms don't have a
+ sys/queue.h, and the ones that do have diverged in incompatible
+ ways. (CIRCLEQ or no CIRCLEQ? SIMPLQ or STAILQ?)
+
+
diff --git a/src/ext/include.am b/src/ext/include.am
index fa9ee94..ea7e58e 100644
--- a/src/ext/include.am
+++ b/src/ext/include.am
@@ -9,7 +9,8 @@ EXTHEADERS = \
src/ext/tinytest.h \
src/ext/strlcat.c \
src/ext/strlcpy.c \
- src/ext/tinytest_macros.h
+ src/ext/tinytest_macros.h \
+ src/ext/tor_queue.h
noinst_HEADERS+= $(EXTHEADERS)
diff --git a/src/ext/tor_queue.h b/src/ext/tor_queue.h
new file mode 100644
index 0000000..622301d
--- /dev/null
+++ b/src/ext/tor_queue.h
@@ -0,0 +1,568 @@
+/* $OpenBSD: queue.h,v 1.36 2012/04/11 13:29:14 naddy Exp $ */
+/* $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft 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 before or 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.
+ */
+
+#if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
+#define _Q_INVALIDATE(a) (a) = ((void *)-1)
+#else
+#define _Q_INVALIDATE(a)
+#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) (SLIST_FIRST(head) == SLIST_END(head))
+#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
+
+#define SLIST_FOREACH(var, head, field) \
+ for((var) = SLIST_FIRST(head); \
+ (var) != SLIST_END(head); \
+ (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))
+
+/*
+ * Singly-linked List functions.
+ */
+#define SLIST_INIT(head) { \
+ SLIST_FIRST(head) = SLIST_END(head); \
+}
+
+#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
+ (elm)->field.sle_next = (slistelm)->field.sle_next; \
+ (slistelm)->field.sle_next = (elm); \
+} while (0)
+
+#define SLIST_INSERT_HEAD(head, elm, field) do { \
+ (elm)->field.sle_next = (head)->slh_first; \
+ (head)->slh_first = (elm); \
+} while (0)
+
+#define SLIST_REMOVE_AFTER(elm, field) do { \
+ (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next; \
+} while (0)
+
+#define SLIST_REMOVE_HEAD(head, field) do { \
+ (head)->slh_first = (head)->slh_first->field.sle_next; \
+} while (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; \
+ _Q_INVALIDATE((elm)->field.sle_next); \
+ } \
+} while (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) (LIST_FIRST(head) == LIST_END(head))
+#define LIST_NEXT(elm, field) ((elm)->field.le_next)
+
+#define LIST_FOREACH(var, head, field) \
+ for((var) = LIST_FIRST(head); \
+ (var)!= LIST_END(head); \
+ (var) = LIST_NEXT(var, field))
+
+#define LIST_FOREACH_SAFE(var, head, field, tvar) \
+ for ((var) = LIST_FIRST(head); \
+ (var) && ((tvar) = LIST_NEXT(var, field), 1); \
+ (var) = (tvar))
+
+/*
+ * List functions.
+ */
+#define LIST_INIT(head) do { \
+ LIST_FIRST(head) = LIST_END(head); \
+} while (0)
+
+#define LIST_INSERT_AFTER(listelm, elm, field) do { \
+ if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
+ (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 (0)
+
+#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
+ (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 (0)
+
+#define LIST_INSERT_HEAD(head, elm, field) do { \
+ if (((elm)->field.le_next = (head)->lh_first) != NULL) \
+ (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
+ (head)->lh_first = (elm); \
+ (elm)->field.le_prev = &(head)->lh_first; \
+} while (0)
+
+#define LIST_REMOVE(elm, field) do { \
+ 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; \
+ _Q_INVALIDATE((elm)->field.le_prev); \
+ _Q_INVALIDATE((elm)->field.le_next); \
+} while (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); \
+ _Q_INVALIDATE((elm)->field.le_prev); \
+ _Q_INVALIDATE((elm)->field.le_next); \
+} while (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) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
+#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
+
+#define SIMPLEQ_FOREACH(var, head, field) \
+ for((var) = SIMPLEQ_FIRST(head); \
+ (var) != SIMPLEQ_END(head); \
+ (var) = SIMPLEQ_NEXT(var, field))
+
+#define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \
+ for ((var) = SIMPLEQ_FIRST(head); \
+ (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1); \
+ (var) = (tvar))
+
+/*
+ * Simple queue functions.
+ */
+#define SIMPLEQ_INIT(head) do { \
+ (head)->sqh_first = NULL; \
+ (head)->sqh_last = &(head)->sqh_first; \
+} while (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 (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 (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 (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 (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 (0)
+
+/*
+ * Tail queue definitions.
+ */
+#define TAILQ_HEAD(name, type) \
+struct name { \
+ struct type *tqh_first; /* first element */ \
+ struct type **tqh_last; /* addr of last next element */ \
+}
+
+#define TAILQ_HEAD_INITIALIZER(head) \
+ { NULL, &(head).tqh_first }
+
+#define TAILQ_ENTRY(type) \
+struct { \
+ struct type *tqe_next; /* next element */ \
+ struct type **tqe_prev; /* address of previous next element */ \
+}
+
+/*
+ * 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 *)((head)->tqh_last))->tqh_last))
+/* XXX */
+#define TAILQ_PREV(elm, headname, field) \
+ (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
+#define TAILQ_EMPTY(head) \
+ (TAILQ_FIRST(head) == TAILQ_END(head))
+
+#define TAILQ_FOREACH(var, head, field) \
+ for((var) = TAILQ_FIRST(head); \
+ (var) != TAILQ_END(head); \
+ (var) = TAILQ_NEXT(var, field))
+
+#define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
+ for ((var) = TAILQ_FIRST(head); \
+ (var) != TAILQ_END(head) && \
+ ((tvar) = TAILQ_NEXT(var, field), 1); \
+ (var) = (tvar))
+
+
+#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, tvar) \
+ for ((var) = TAILQ_LAST(head, headname); \
+ (var) != TAILQ_END(head) && \
+ ((tvar) = TAILQ_PREV(var, headname, field), 1); \
+ (var) = (tvar))
+
+/*
+ * Tail queue functions.
+ */
+#define TAILQ_INIT(head) do { \
+ (head)->tqh_first = NULL; \
+ (head)->tqh_last = &(head)->tqh_first; \
+} while (0)
+
+#define TAILQ_INSERT_HEAD(head, elm, field) do { \
+ if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
+ (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 (0)
+
+#define TAILQ_INSERT_TAIL(head, elm, field) do { \
+ (elm)->field.tqe_next = NULL; \
+ (elm)->field.tqe_prev = (head)->tqh_last; \
+ *(head)->tqh_last = (elm); \
+ (head)->tqh_last = &(elm)->field.tqe_next; \
+} while (0)
+
+#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
+ if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
+ (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 (0)
+
+#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
+ (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 (0)
+
+#define TAILQ_REMOVE(head, elm, field) do { \
+ if (((elm)->field.tqe_next) != NULL) \
+ (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; \
+ _Q_INVALIDATE((elm)->field.tqe_prev); \
+ _Q_INVALIDATE((elm)->field.tqe_next); \
+} while (0)
+
+#define TAILQ_REPLACE(head, elm, elm2, field) do { \
+ if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \
+ (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); \
+ _Q_INVALIDATE((elm)->field.tqe_prev); \
+ _Q_INVALIDATE((elm)->field.tqe_next); \
+} while (0)
+
+/*
+ * Circular queue definitions.
+ */
+#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 access methods
+ */
+#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
+#define CIRCLEQ_LAST(head) ((head)->cqh_last)
+#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_END(head))
+
+#define CIRCLEQ_FOREACH(var, head, field) \
+ for((var) = CIRCLEQ_FIRST(head); \
+ (var) != CIRCLEQ_END(head); \
+ (var) = CIRCLEQ_NEXT(var, field))
+
+#define CIRCLEQ_FOREACH_SAFE(var, head, field, tvar) \
+ for ((var) = CIRCLEQ_FIRST(head); \
+ (var) != CIRCLEQ_END(head) && \
+ ((tvar) = CIRCLEQ_NEXT(var, field), 1); \
+ (var) = (tvar))
+
+#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
+ for((var) = CIRCLEQ_LAST(head); \
+ (var) != CIRCLEQ_END(head); \
+ (var) = CIRCLEQ_PREV(var, field))
+
+#define CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
+ for ((var) = CIRCLEQ_LAST(head, headname); \
+ (var) != CIRCLEQ_END(head) && \
+ ((tvar) = CIRCLEQ_PREV(var, headname, field), 1); \
+ (var) = (tvar))
+
+/*
+ * Circular queue functions.
+ */
+#define CIRCLEQ_INIT(head) do { \
+ (head)->cqh_first = CIRCLEQ_END(head); \
+ (head)->cqh_last = CIRCLEQ_END(head); \
+} while (0)
+
+#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
+ (elm)->field.cqe_next = (listelm)->field.cqe_next; \
+ (elm)->field.cqe_prev = (listelm); \
+ if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \
+ (head)->cqh_last = (elm); \
+ else \
+ (listelm)->field.cqe_next->field.cqe_prev = (elm); \
+ (listelm)->field.cqe_next = (elm); \
+} while (0)
+
+#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
+ (elm)->field.cqe_next = (listelm); \
+ (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
+ if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \
+ (head)->cqh_first = (elm); \
+ else \
+ (listelm)->field.cqe_prev->field.cqe_next = (elm); \
+ (listelm)->field.cqe_prev = (elm); \
+} while (0)
+
+#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
+ (elm)->field.cqe_next = (head)->cqh_first; \
+ (elm)->field.cqe_prev = CIRCLEQ_END(head); \
+ if ((head)->cqh_last == CIRCLEQ_END(head)) \
+ (head)->cqh_last = (elm); \
+ else \
+ (head)->cqh_first->field.cqe_prev = (elm); \
+ (head)->cqh_first = (elm); \
+} while (0)
+
+#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
+ (elm)->field.cqe_next = CIRCLEQ_END(head); \
+ (elm)->field.cqe_prev = (head)->cqh_last; \
+ if ((head)->cqh_first == CIRCLEQ_END(head)) \
+ (head)->cqh_first = (elm); \
+ else \
+ (head)->cqh_last->field.cqe_next = (elm); \
+ (head)->cqh_last = (elm); \
+} while (0)
+
+#define CIRCLEQ_REMOVE(head, elm, field) do { \
+ if ((elm)->field.cqe_next == CIRCLEQ_END(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_END(head)) \
+ (head)->cqh_first = (elm)->field.cqe_next; \
+ else \
+ (elm)->field.cqe_prev->field.cqe_next = \
+ (elm)->field.cqe_next; \
+ _Q_INVALIDATE((elm)->field.cqe_prev); \
+ _Q_INVALIDATE((elm)->field.cqe_next); \
+} while (0)
+
+#define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \
+ if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \
+ CIRCLEQ_END(head)) \
+ (head).cqh_last = (elm2); \
+ else \
+ (elm2)->field.cqe_next->field.cqe_prev = (elm2); \
+ if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \
+ CIRCLEQ_END(head)) \
+ (head).cqh_first = (elm2); \
+ else \
+ (elm2)->field.cqe_prev->field.cqe_next = (elm2); \
+ _Q_INVALIDATE((elm)->field.cqe_prev); \
+ _Q_INVALIDATE((elm)->field.cqe_next); \
+} while (0)
+
+#endif /* !_SYS_QUEUE_H_ */
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