/* * 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