1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ 2 3 #pragma once 4 5 /*** 6 This file is part of systemd. 7 8 Copyright 2010 Lennart Poettering 9 10 systemd is free software; you can redistribute it and/or modify it 11 under the terms of the GNU Lesser General Public License as published by 12 the Free Software Foundation; either version 2.1 of the License, or 13 (at your option) any later version. 14 15 systemd is distributed in the hope that it will be useful, but 16 WITHOUT ANY WARRANTY; without even the implied warranty of 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 Lesser General Public License for more details. 19 20 You should have received a copy of the GNU Lesser General Public License 21 along with systemd; If not, see <http://www.gnu.org/licenses/>. 22 ***/ 23 24 /* The head of the linked list. Use this in the structure that shall 25 * contain the head of the linked list */ 26 #define LIST_HEAD(t,name) \ 27 t *name 28 29 /* The pointers in the linked list's items. Use this in the item structure */ 30 #define LIST_FIELDS(t,name) \ 31 t *name##_next, *name##_prev 32 33 /* Initialize the list's head */ 34 #define LIST_HEAD_INIT(head) \ 35 do { \ 36 (head) = NULL; } \ 37 while(false) 38 39 /* Initialize a list item */ 40 #define LIST_INIT(name,item) \ 41 do { \ 42 typeof(*(item)) *_item = (item); \ 43 assert(_item); \ 44 _item->name##_prev = _item->name##_next = NULL; \ 45 } while(false) 46 47 /* Prepend an item to the list */ 48 #define LIST_PREPEND(name,head,item) \ 49 do { \ 50 typeof(*(head)) **_head = &(head), *_item = (item); \ 51 assert(_item); \ 52 if ((_item->name##_next = *_head)) \ 53 _item->name##_next->name##_prev = _item; \ 54 _item->name##_prev = NULL; \ 55 *_head = _item; \ 56 } while(false) 57 58 /* Remove an item from the list */ 59 #define LIST_REMOVE(name,head,item) \ 60 do { \ 61 typeof(*(head)) **_head = &(head), *_item = (item); \ 62 assert(_item); \ 63 if (_item->name##_next) \ 64 _item->name##_next->name##_prev = _item->name##_prev; \ 65 if (_item->name##_prev) \ 66 _item->name##_prev->name##_next = _item->name##_next; \ 67 else { \ 68 assert(*_head == _item); \ 69 *_head = _item->name##_next; \ 70 } \ 71 _item->name##_next = _item->name##_prev = NULL; \ 72 } while(false) 73 74 /* Find the head of the list */ 75 #define LIST_FIND_HEAD(name,item,head) \ 76 do { \ 77 typeof(*(item)) *_item = (item); \ 78 if (!_item) \ 79 (head) = NULL; \ 80 else { \ 81 while (_item->name##_prev) \ 82 _item = _item->name##_prev; \ 83 (head) = _item; \ 84 } \ 85 } while (false) 86 87 /* Find the tail of the list */ 88 #define LIST_FIND_TAIL(name,item,tail) \ 89 do { \ 90 typeof(*(item)) *_item = (item); \ 91 if (!_item) \ 92 (tail) = NULL; \ 93 else { \ 94 while (_item->name##_next) \ 95 _item = _item->name##_next; \ 96 (tail) = _item; \ 97 } \ 98 } while (false) 99 100 /* Insert an item after another one (a = where, b = what) */ 101 #define LIST_INSERT_AFTER(name,head,a,b) \ 102 do { \ 103 typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \ 104 assert(_b); \ 105 if (!_a) { \ 106 if ((_b->name##_next = *_head)) \ 107 _b->name##_next->name##_prev = _b; \ 108 _b->name##_prev = NULL; \ 109 *_head = _b; \ 110 } else { \ 111 if ((_b->name##_next = _a->name##_next)) \ 112 _b->name##_next->name##_prev = _b; \ 113 _b->name##_prev = _a; \ 114 _a->name##_next = _b; \ 115 } \ 116 } while(false) 117 118 #define LIST_JUST_US(name,item) \ 119 (!(item)->name##_prev && !(item)->name##_next) \ 120 121 #define LIST_FOREACH(name,i,head) \ 122 for ((i) = (head); (i); (i) = (i)->name##_next) 123 124 #define LIST_FOREACH_SAFE(name,i,n,head) \ 125 for ((i) = (head); (i) && (((n) = (i)->name##_next), 1); (i) = (n)) 126 127 #define LIST_FOREACH_BEFORE(name,i,p) \ 128 for ((i) = (p)->name##_prev; (i); (i) = (i)->name##_prev) 129 130 #define LIST_FOREACH_AFTER(name,i,p) \ 131 for ((i) = (p)->name##_next; (i); (i) = (i)->name##_next) 132 133 /* Loop starting from p->next until p->prev. 134 p can be adjusted meanwhile. */ 135 #define LIST_LOOP_BUT_ONE(name,i,head,p) \ 136 for ((i) = (p)->name##_next ? (p)->name##_next : (head); \ 137 (i) != (p); \ 138 (i) = (i)->name##_next ? (i)->name##_next : (head)) 139