queue.h
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- /*
- * 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
- */
- /*
- * XXX
- * We #undef the queue macros because there are incompatible versions of this
- * file and these macros on various systems. What makes the problem worse is
- * they are included and/or defined by system include files which we may have
- * already loaded into Berkeley DB before getting here. For example, FreeBSD's
- * <rpc/rpc.h> includes its system <sys/queue.h>, and VxWorks UnixLib.h defines
- * several of the LIST_XXX macros. Make sure we use ours.
- */
- #undef LIST_HEAD
- #undef LIST_ENTRY
- #undef LIST_FIRST
- #undef LIST_NEXT
- #undef LIST_INIT
- #undef LIST_INSERT_AFTER
- #undef LIST_INSERT_BEFORE
- #undef LIST_INSERT_HEAD
- #undef LIST_REMOVE
- #undef TAILQ_HEAD
- #undef TAILQ_ENTRY
- #undef TAILQ_FIRST
- #undef TAILQ_NEXT
- #undef TAILQ_INIT
- #undef TAILQ_INSERT_HEAD
- #undef TAILQ_INSERT_TAIL
- #undef TAILQ_INSERT_AFTER
- #undef TAILQ_INSERT_BEFORE
- #undef TAILQ_REMOVE
- #undef CIRCLEQ_HEAD
- #undef CIRCLEQ_ENTRY
- #undef CIRCLEQ_FIRST
- #undef CIRCLEQ_LAST
- #undef CIRCLEQ_NEXT
- #undef CIRCLEQ_PREV
- #undef CIRCLEQ_INIT
- #undef CIRCLEQ_INSERT_AFTER
- #undef CIRCLEQ_INSERT_BEFORE
- #undef CIRCLEQ_INSERT_HEAD
- #undef CIRCLEQ_INSERT_TAIL
- #undef CIRCLEQ_REMOVE
- /*
- * This file defines three types of data structures: lists, tail queues,
- * and circular queues.
- *
- * 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 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 only be traversed in the forward 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(__cplusplus)
- extern "C" {
- #endif
- /*
- * List definitions.
- */
- #define LIST_HEAD(name, type)
- struct name {
- struct type *lh_first; /* first element */
- }
- #define LIST_ENTRY(type)
- struct {
- struct type *le_next; /* next element */
- struct type **le_prev; /* address of previous next element */
- }
- #define LIST_FIRST(head) ((head)->lh_first)
- #define LIST_NEXT(elm, field) ((elm)->field.le_next)
- /*
- * List functions.
- */
- #define LIST_INIT(head) {
- (head)->lh_first = NULL;
- }
- #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;
- } 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_ENTRY(type)
- struct {
- struct type *tqe_next; /* next element */
- struct type **tqe_prev; /* address of previous next element */
- }
- #define TAILQ_FIRST(head) ((head)->tqh_first)
- #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
- /*
- * 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;
- } while (0)
- /*
- * This macro is used to fixup the queue after moving the head.
- */
- #define TAILQ_REINSERT_HEAD(head, elm, field) do {
- DB_ASSERT((head)->tqh_first == (elm));
- (elm)->field.tqe_prev = &(head)->tqh_first;
- } 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_ENTRY(type)
- struct {
- struct type *cqe_next; /* next element */
- struct type *cqe_prev; /* previous element */
- }
- #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
- #define CIRCLEQ_LAST(head) ((head)->cqh_last)
- #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
- #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
- /*
- * Circular queue functions.
- */
- #define CIRCLEQ_INIT(head) do {
- (head)->cqh_first = (void *)(head);
- (head)->cqh_last = (void *)(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 == (void *)(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 == (void *)(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 = (void *)(head);
- if ((head)->cqh_last == (void *)(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 = (void *)(head);
- (elm)->field.cqe_prev = (head)->cqh_last;
- if ((head)->cqh_first == (void *)(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 == (void *)(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 == (void *)(head))
- (head)->cqh_first = (elm)->field.cqe_next;
- else
- (elm)->field.cqe_prev->field.cqe_next =
- (elm)->field.cqe_next;
- } while (0)
- #if defined(__cplusplus)
- }
- #endif