/* $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $ */ /* * QEMU version: Copy from netbsd, removed debug code, removed some of * the implementations. Left in singly-linked lists, lists, simple * queues, and 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 QEMU_SYS_QUEUE_H #define QEMU_SYS_QUEUE_H /* * This file defines four types of data structures: singly-linked lists, * lists, simple queues, and tail 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. * * For details on the use of these macros, see the queue(3) manual page. */ /* * List definitions. */ #define QLIST_HEAD(name, type) \ struct name { \ struct type *lh_first; /* first element */ \ } #define QLIST_HEAD_INITIALIZER(head) \ { NULL } #define QLIST_ENTRY(type) \ struct { \ struct type *le_next; /* next element */ \ struct type **le_prev; /* address of previous next element */ \ } /* * List functions. */ #define QLIST_INIT(head) do { \ (head)->lh_first = NULL; \ } while (/*CONSTCOND*/0) #define QLIST_SWAP(dstlist, srclist, field) do { \ void *tmplist; \ tmplist = (srclist)->lh_first; \ (srclist)->lh_first = (dstlist)->lh_first; \ if ((srclist)->lh_first != NULL) { \ (srclist)->lh_first->field.le_prev = &(srclist)->lh_first; \ } \ (dstlist)->lh_first = tmplist; \ if ((dstlist)->lh_first != NULL) { \ (dstlist)->lh_first->field.le_prev = &(dstlist)->lh_first; \ } \ } while (/*CONSTCOND*/0) #define QLIST_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 (/*CONSTCOND*/0) #define QLIST_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 (/*CONSTCOND*/0) #define QLIST_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 (/*CONSTCOND*/0) #define QLIST_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; \ (elm)->field.le_next = NULL; \ (elm)->field.le_prev = NULL; \ } while (/*CONSTCOND*/0) /* * Like QLIST_REMOVE() but safe to call when elm is not in a list */ #define QLIST_SAFE_REMOVE(elm, field) do { \ if ((elm)->field.le_prev != NULL) { \ 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; \ (elm)->field.le_next = NULL; \ (elm)->field.le_prev = NULL; \ } \ } while (/*CONSTCOND*/0) /* Is elm in a list? */ #define QLIST_IS_INSERTED(elm, field) ((elm)->field.le_prev != NULL) #define QLIST_FOREACH(var, head, field) \ for ((var) = ((head)->lh_first); \ (var); \ (var) = ((var)->field.le_next)) #define QLIST_FOREACH_SAFE(var, head, field, next_var) \ for ((var) = ((head)->lh_first); \ (var) && ((next_var) = ((var)->field.le_next), 1); \ (var) = (next_var)) /* * List access methods. */ #define QLIST_EMPTY(head) ((head)->lh_first == NULL) #define QLIST_FIRST(head) ((head)->lh_first) #define QLIST_NEXT(elm, field) ((elm)->field.le_next) /* * Singly-linked List definitions. */ #define QSLIST_HEAD(name, type) \ struct name { \ struct type *slh_first; /* first element */ \ } #define QSLIST_HEAD_INITIALIZER(head) \ { NULL } #define QSLIST_ENTRY(type) \ struct { \ struct type *sle_next; /* next element */ \ } /* * Singly-linked List functions. */ #define QSLIST_INIT(head) do { \ (head)->slh_first = NULL; \ } while (/*CONSTCOND*/0) #define QSLIST_INSERT_AFTER(slistelm, elm, field) do { \ (elm)->field.sle_next = (slistelm)->field.sle_next; \ (slistelm)->field.sle_next = (elm); \ } while (/*CONSTCOND*/0) #define QSLIST_INSERT_HEAD(head, elm, field) do { \ (elm)->field.sle_next = (head)->slh_first; \ (head)->slh_first = (elm); \ } while (/*CONSTCOND*/0) #define QSLIST_INSERT_HEAD_ATOMIC(head, elm, field) do { \ typeof(elm) save_sle_next; \ do { \ save_sle_next = (elm)->field.sle_next = (head)->slh_first; \ } while (qatomic_cmpxchg(&(head)->slh_first, save_sle_next, (elm)) !=\ save_sle_next); \ } while (/*CONSTCOND*/0) #define QSLIST_MOVE_ATOMIC(dest, src) do { \ (dest)->slh_first = qatomic_xchg(&(src)->slh_first, NULL); \ } while (/*CONSTCOND*/0) #define QSLIST_REMOVE_HEAD(head, field) do { \ typeof((head)->slh_first) elm = (head)->slh_first; \ (head)->slh_first = elm->field.sle_next; \ elm->field.sle_next = NULL; \ } while (/*CONSTCOND*/0) #define QSLIST_REMOVE_AFTER(slistelm, field) do { \ typeof(slistelm) next = (slistelm)->field.sle_next; \ (slistelm)->field.sle_next = next->field.sle_next; \ next->field.sle_next = NULL; \ } while (/*CONSTCOND*/0) #define QSLIST_REMOVE(head, elm, type, field) do { \ if ((head)->slh_first == (elm)) { \ QSLIST_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; \ (elm)->field.sle_next = NULL; \ } \ } while (/*CONSTCOND*/0) #define QSLIST_FOREACH(var, head, field) \ for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) #define QSLIST_FOREACH_SAFE(var, head, field, tvar) \ for ((var) = QSLIST_FIRST((head)); \ (var) && ((tvar) = QSLIST_NEXT((var), field), 1); \ (var) = (tvar)) /* * Singly-linked List access methods. */ #define QSLIST_EMPTY(head) ((head)->slh_first == NULL) #define QSLIST_FIRST(head) ((head)->slh_first) #define QSLIST_NEXT(elm, field) ((elm)->field.sle_next) /* * Simple queue definitions. */ #define QSIMPLEQ_HEAD(name, type) \ struct name { \ struct type *sqh_first; /* first element */ \ struct type **sqh_last; /* addr of last next element */ \ } #define QSIMPLEQ_HEAD_INITIALIZER(head) \ { NULL, &(head).sqh_first } #define QSIMPLEQ_ENTRY(type) \ struct { \ struct type *sqe_next; /* next element */ \ } /* * Simple queue functions. */ #define QSIMPLEQ_INIT(head) do { \ (head)->sqh_first = NULL; \ (head)->sqh_last = &(head)->sqh_first; \ } while (/*CONSTCOND*/0) #define QSIMPLEQ_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 QSIMPLEQ_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 QSIMPLEQ_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 QSIMPLEQ_REMOVE_HEAD(head, field) do { \ typeof((head)->sqh_first) elm = (head)->sqh_first; \ if (((head)->sqh_first = elm->field.sqe_next) == NULL) \ (head)->sqh_last = &(head)->sqh_first; \ elm->field.sqe_next = NULL; \ } while (/*CONSTCOND*/0) #define QSIMPLEQ_SPLIT_AFTER(head, elm, field, removed) do { \ QSIMPLEQ_INIT(removed); \ if (((removed)->sqh_first = (head)->sqh_first) != NULL) { \ if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) { \ (head)->sqh_last = &(head)->sqh_first; \ } \ (removed)->sqh_last = &(elm)->field.sqe_next; \ (elm)->field.sqe_next = NULL; \ } \ } while (/*CONSTCOND*/0) #define QSIMPLEQ_REMOVE(head, elm, type, field) do { \ if ((head)->sqh_first == (elm)) { \ QSIMPLEQ_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; \ (elm)->field.sqe_next = NULL; \ } \ } while (/*CONSTCOND*/0) #define QSIMPLEQ_FOREACH(var, head, field) \ for ((var) = ((head)->sqh_first); \ (var); \ (var) = ((var)->field.sqe_next)) #define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \ for ((var) = ((head)->sqh_first); \ (var) && ((next = ((var)->field.sqe_next)), 1); \ (var) = (next)) #define QSIMPLEQ_CONCAT(head1, head2) do { \ if (!QSIMPLEQ_EMPTY((head2))) { \ *(head1)->sqh_last = (head2)->sqh_first; \ (head1)->sqh_last = (head2)->sqh_last; \ QSIMPLEQ_INIT((head2)); \ } \ } while (/*CONSTCOND*/0) #define QSIMPLEQ_PREPEND(head1, head2) do { \ if (!QSIMPLEQ_EMPTY((head2))) { \ *(head2)->sqh_last = (head1)->sqh_first; \ (head1)->sqh_first = (head2)->sqh_first; \ QSIMPLEQ_INIT((head2)); \ } \ } while (/*CONSTCOND*/0) #define QSIMPLEQ_LAST(head, type, field) \ (QSIMPLEQ_EMPTY((head)) ? \ NULL : \ ((struct type *)(void *) \ ((char *)((head)->sqh_last) - offsetof(struct type, field)))) /* * Simple queue access methods. */ #define QSIMPLEQ_EMPTY_ATOMIC(head) \ (qatomic_read(&((head)->sqh_first)) == NULL) #define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) #define QSIMPLEQ_FIRST(head) ((head)->sqh_first) #define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 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. */ #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 */ \ } /* * Tail queue functions. */ #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; \ (elm)->field.tqe_circ.tql_next = NULL; \ (elm)->field.tqe_next = NULL; \ } while (/*CONSTCOND*/0) /* remove @left, @right and all elements in between from @head */ #define QTAILQ_REMOVE_SEVERAL(head, left, right, field) do { \ if (((right)->field.tqe_next) != NULL) \ (right)->field.tqe_next->field.tqe_circ.tql_prev = \ (left)->field.tqe_circ.tql_prev; \ else \ (head)->tqh_circ.tql_prev = (left)->field.tqe_circ.tql_prev; \ (left)->field.tqe_circ.tql_prev->tql_next = (right)->field.tqe_next; \ } 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), 1); \ (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) #define QLIST_RAW_FIRST(head) \ field_at_offset(head, 0, void *) #define QLIST_RAW_NEXT(elm, entry) \ field_at_offset(elm, entry, void *) #define QLIST_RAW_PREVIOUS(elm, entry) \ field_at_offset(elm, entry + sizeof(void *), void *) #define QLIST_RAW_FOREACH(elm, head, entry) \ for ((elm) = *QLIST_RAW_FIRST(head); \ (elm); \ (elm) = *QLIST_RAW_NEXT(elm, entry)) #define QLIST_RAW_INSERT_AFTER(head, prev, elem, entry) do { \ *QLIST_RAW_NEXT(prev, entry) = elem; \ *QLIST_RAW_PREVIOUS(elem, entry) = QLIST_RAW_NEXT(prev, entry); \ *QLIST_RAW_NEXT(elem, entry) = NULL; \ } while (0) #define QLIST_RAW_INSERT_HEAD(head, elm, entry) do { \ void *first = *QLIST_RAW_FIRST(head); \ *QLIST_RAW_FIRST(head) = elm; \ *QLIST_RAW_PREVIOUS(elm, entry) = QLIST_RAW_FIRST(head); \ if (first) { \ *QLIST_RAW_NEXT(elm, entry) = first; \ *QLIST_RAW_PREVIOUS(first, entry) = QLIST_RAW_NEXT(elm, entry); \ } else { \ *QLIST_RAW_NEXT(elm, entry) = NULL; \ } \ } while (0) #endif /* QEMU_SYS_QUEUE_H */