1 /* $NetBSD: pthread_queue.h,v 1.4 2008/04/28 20:23:01 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Nathan J. Williams. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* pthread_queue.h 33 * Definition of a queue interface for the pthread library. 34 * Style modeled on the sys/queue.h macros; implementation taken from 35 * the tail queue, with the added property of static initializability 36 * (and a corresponding extra cost in the _INSERT_TAIL() function. 37 */ 38 39 40 41 /* 42 * Queue definitions. 43 */ 44 #define PTQ_HEAD(name, type) \ 45 struct name { \ 46 struct type *ptqh_first;/* first element */ \ 47 struct type **ptqh_last;/* addr of last next element */ \ 48 } 49 50 #define PTQ_HEAD_INITIALIZER { NULL, NULL } 51 52 53 #define PTQ_ENTRY(type) \ 54 struct { \ 55 struct type *ptqe_next; /* next element */ \ 56 struct type **ptqe_prev;/* address of previous next element */ \ 57 } 58 59 /* 60 * Queue functions. 61 */ 62 63 #define PTQ_INIT(head) do { \ 64 (head)->ptqh_first = NULL; \ 65 (head)->ptqh_last = &(head)->ptqh_first; \ 66 } while (/*CONSTCOND*/0) 67 68 #define PTQ_INSERT_HEAD(head, elm, field) do { \ 69 if (((elm)->field.ptqe_next = (head)->ptqh_first) != NULL) \ 70 (head)->ptqh_first->field.ptqe_prev = \ 71 &(elm)->field.ptqe_next; \ 72 else \ 73 (head)->ptqh_last = &(elm)->field.ptqe_next; \ 74 (head)->ptqh_first = (elm); \ 75 (elm)->field.ptqe_prev = &(head)->ptqh_first; \ 76 } while (/*CONSTCOND*/0) 77 78 #define PTQ_INSERT_TAIL(head, elm, field) do { \ 79 (elm)->field.ptqe_next = NULL; \ 80 if ((head)->ptqh_last == NULL) \ 81 (head)->ptqh_last = &(head)->ptqh_first; \ 82 (elm)->field.ptqe_prev = (head)->ptqh_last; \ 83 *(head)->ptqh_last = (elm); \ 84 (head)->ptqh_last = &(elm)->field.ptqe_next; \ 85 } while (/*CONSTCOND*/0) 86 87 #define PTQ_INSERT_AFTER(head, listelm, elm, field) do { \ 88 if (((elm)->field.ptqe_next = (listelm)->field.ptqe_next) != NULL)\ 89 (elm)->field.ptqe_next->field.ptqe_prev = \ 90 &(elm)->field.ptqe_next; \ 91 else \ 92 (head)->ptqh_last = &(elm)->field.ptqe_next; \ 93 (listelm)->field.ptqe_next = (elm); \ 94 (elm)->field.ptqe_prev = &(listelm)->field.ptqe_next; \ 95 } while (/*CONSTCOND*/0) 96 97 #define PTQ_INSERT_BEFORE(listelm, elm, field) do { \ 98 (elm)->field.ptqe_prev = (listelm)->field.ptqe_prev; \ 99 (elm)->field.ptqe_next = (listelm); \ 100 *(listelm)->field.ptqe_prev = (elm); \ 101 (listelm)->field.ptqe_prev = &(elm)->field.ptqe_next; \ 102 } while (/*CONSTCOND*/0) 103 104 #define PTQ_REMOVE(head, elm, field) do { \ 105 if (((elm)->field.ptqe_next) != NULL) \ 106 (elm)->field.ptqe_next->field.ptqe_prev = \ 107 (elm)->field.ptqe_prev; \ 108 else \ 109 (head)->ptqh_last = (elm)->field.ptqe_prev; \ 110 *(elm)->field.ptqe_prev = (elm)->field.ptqe_next; \ 111 } while (/*CONSTCOND*/0) 112 113 /* 114 * Queue access methods. 115 */ 116 #define PTQ_EMPTY(head) ((head)->ptqh_first == NULL) 117 #define PTQ_FIRST(head) ((head)->ptqh_first) 118 #define PTQ_NEXT(elm, field) ((elm)->field.ptqe_next) 119 120 #define PTQ_LAST(head, headname) \ 121 (*(((struct headname *)(void *)((head)->ptqh_last))->ptqh_last)) 122 #define PTQ_PREV(elm, headname, field) \ 123 (*(((struct headname *)(void *)((elm)->field.ptqe_prev))->ptqh_last)) 124 125 #define PTQ_FOREACH(var, head, field) \ 126 for ((var) = ((head)->ptqh_first); \ 127 (var); \ 128 (var) = ((var)->field.ptqe_next)) 129 130 #define PTQ_FOREACH_REVERSE(var, head, headname, field) \ 131 for ((var) = (*(((struct headname *)(void *)((head)->ptqh_last))->ptqh_last)); \ 132 (var); \ 133 (var) = (*(((struct headname *)(void *)((var)->field.ptqe_prev))->ptqh_last))) 134