1/* 2 * Copyright (C) 2002 Free Software Foundation, Inc. 3 * (originally part of the GNU C Library and Userspace RCU) 4 * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. 5 * 6 * Copyright (C) 2009 Pierre-Marc Fournier 7 * Conversion to RCU list. 8 * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> 9 * 10 * This library is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU Lesser General Public 12 * License as published by the Free Software Foundation; either 13 * version 2.1 of the License, or (at your option) any later version. 14 * 15 * This library is distributed in the hope that it will be useful, 16 * but 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 21 * License along with this library; if not, see 22 * <http://www.gnu.org/licenses/>. 23 */ 24 25#ifndef LIST_H 26#define LIST_H 1 27 28/* 29 * The definitions of this file are adopted from those which can be 30 * found in the Linux kernel headers to enable people familiar with the 31 * latter find their way in these sources as well. 32 */ 33 34/* Basic type for the double-link list. */ 35struct list_head { 36 struct list_head *next, *prev; 37}; 38 39/* Define a variable with the head and tail of the list. */ 40#define LIST_HEAD(name) \ 41 struct list_head name = { &(name), &(name) } 42 43/* Initialize a new list head. */ 44#define INIT_LIST_HEAD(ptr) \ 45 (ptr)->next = (ptr)->prev = (ptr) 46 47#define LIST_HEAD_INIT(name) { &(name), &(name) } 48 49/* Add new element at the head of the list. */ 50static inline void list_add(struct list_head *newp, struct list_head *head) 51{ 52 head->next->prev = newp; 53 newp->next = head->next; 54 newp->prev = head; 55 head->next = newp; 56} 57 58/* Add new element at the tail of the list. */ 59static inline void list_add_tail(struct list_head *newp, struct list_head *head) 60{ 61 head->prev->next = newp; 62 newp->next = head; 63 newp->prev = head->prev; 64 head->prev = newp; 65} 66 67/* Remove element from list. */ 68static inline void __list_del(struct list_head *prev, struct list_head *next) 69{ 70 next->prev = prev; 71 prev->next = next; 72} 73 74/* Remove element from list. */ 75static inline void list_del(struct list_head *elem) 76{ 77 __list_del(elem->prev, elem->next); 78} 79 80/* Remove element from list, initializing the element's list pointers. */ 81static inline void list_del_init(struct list_head *elem) 82{ 83 list_del(elem); 84 INIT_LIST_HEAD(elem); 85} 86 87/* Delete from list, add to another list as head. */ 88static inline void list_move(struct list_head *elem, struct list_head *head) 89{ 90 __list_del(elem->prev, elem->next); 91 list_add(elem, head); 92} 93 94/* Replace an old entry. */ 95static inline void list_replace(struct list_head *old, struct list_head *newp) 96{ 97 newp->next = old->next; 98 newp->prev = old->prev; 99 newp->prev->next = newp; 100 newp->next->prev = newp; 101} 102 103/* Join two lists. */ 104static inline void list_splice(struct list_head *add, struct list_head *head) 105{ 106 /* Do nothing if the list which gets added is empty. */ 107 if (add != add->next) { 108 add->next->prev = head; 109 add->prev->next = head->next; 110 head->next->prev = add->prev; 111 head->next = add->next; 112 } 113} 114 115/* Get typed element from list at a given position. */ 116#define list_entry(ptr, type, member) \ 117 ((type *) ((char *) (ptr) - offsetof(type, member))) 118 119/* Get first entry from a list. */ 120#define list_first_entry(ptr, type, member) \ 121 list_entry((ptr)->next, type, member) 122 123/* Iterate forward over the elements of the list. */ 124#define list_for_each(pos, head) \ 125 for (pos = (head)->next; pos != (head); pos = pos->next) 126 127/* 128 * Iterate forward over the elements list. The list elements can be 129 * removed from the list while doing this. 130 */ 131#define list_for_each_safe(pos, p, head) \ 132 for (pos = (head)->next, p = pos->next; \ 133 pos != (head); \ 134 pos = p, p = pos->next) 135 136/* Iterate backward over the elements of the list. */ 137#define list_for_each_prev(pos, head) \ 138 for (pos = (head)->prev; pos != (head); pos = pos->prev) 139 140/* 141 * Iterate backwards over the elements list. The list elements can be 142 * removed from the list while doing this. 143 */ 144#define list_for_each_prev_safe(pos, p, head) \ 145 for (pos = (head)->prev, p = pos->prev; \ 146 pos != (head); \ 147 pos = p, p = pos->prev) 148 149static inline int list_empty(struct list_head *head) 150{ 151 return head == head->next; 152} 153 154static inline void list_replace_init(struct list_head *old, 155 struct list_head *newp) 156{ 157 struct list_head *head = old->next; 158 159 list_del(old); 160 list_add_tail(newp, head); 161 INIT_LIST_HEAD(old); 162} 163 164#endif /* LIST_H */