1/* This code has been stolen from Linux kernel :) */ 2/* distributed under GNU GPL version 2. */ 3 4#ifndef _ATALK_LIST_H 5#define _ATALK_LIST_H 6 7/* 8 * Simple doubly linked list implementation. 9 * 10 * Some of the internal functions ("__xxx") are useful when 11 * manipulating whole lists rather than single entries, as 12 * sometimes we already know the next/prev entries and we can 13 * generate better code by using them directly rather than 14 * using the generic single-entry routines. 15 */ 16 17struct list_head { 18 struct list_head *next, *prev; 19}; 20 21#define ATALK_LIST_HEAD_INIT(name) { &(name), &(name) } 22 23#define ATALK_LIST_HEAD(name) \ 24 struct list_head name = ATALK_LIST_HEAD_INIT(name) 25 26#define ATALK_INIT_LIST_HEAD(ptr) do { \ 27 (ptr)->next = (ptr); (ptr)->prev = (ptr); \ 28} while (0) 29 30#ifdef USE_LIST 31/* 32 * Insert a new entry between two known consecutive entries. 33 * 34 * This is only for internal list manipulation where we know 35 * the prev/next entries already! 36 */ 37static inline void __list_add(struct list_head * new, 38 struct list_head * prev, 39 struct list_head * next) 40{ 41 next->prev = new; 42 new->next = next; 43 new->prev = prev; 44 prev->next = new; 45} 46 47/** 48 * list_add - add a new entry 49 * @new: new entry to be added 50 * @head: list head to add it after 51 * 52 * Insert a new entry after the specified head. 53 * This is good for implementing stacks. 54 */ 55static inline void list_add(struct list_head *new, struct list_head *head) 56{ 57 __list_add(new, head, head->next); 58} 59 60/** 61 * list_add_tail - add a new entry 62 * @new: new entry to be added 63 * @head: list head to add it before 64 * 65 * Insert a new entry before the specified head. 66 * This is useful for implementing queues. 67 */ 68static inline void list_add_tail(struct list_head *new, struct list_head *head) 69{ 70 __list_add(new, head->prev, head); 71} 72 73/* 74 * Delete a list entry by making the prev/next entries 75 * point to each other. 76 * 77 * This is only for internal list manipulation where we know 78 * the prev/next entries already! 79 */ 80static inline void __list_del(struct list_head * prev, 81 struct list_head * next) 82{ 83 next->prev = prev; 84 prev->next = next; 85} 86 87/** 88 * list_del - deletes entry from list. 89 * @entry: the element to delete from the list. 90 * Note: list_empty on entry does not return true after this, the entry is in an undefined state. 91 */ 92static inline void list_del(struct list_head *entry) 93{ 94 __list_del(entry->prev, entry->next); 95} 96 97/** 98 * list_del_init - deletes entry from list and reinitialize it. 99 * @entry: the element to delete from the list. 100 */ 101static inline void list_del_init(struct list_head *entry) 102{ 103 __list_del(entry->prev, entry->next); 104 ATALK_INIT_LIST_HEAD(entry); 105} 106 107/** 108 * list_empty - tests whether a list is empty 109 * @head: the list to test. 110 */ 111static inline int list_empty(struct list_head *head) 112{ 113 return head->next == head; 114} 115 116/** 117 * list_splice - join two lists 118 * @list: the new list to add. 119 * @head: the place to add it in the first list. 120 */ 121static inline void list_splice(struct list_head *list, struct list_head *head) 122{ 123 struct list_head *first = list->next; 124 125 if (first != list) { 126 struct list_head *last = list->prev; 127 struct list_head *at = head->next; 128 129 first->prev = head; 130 head->next = first; 131 132 last->next = at; 133 at->prev = last; 134 } 135} 136 137#endif 138/** 139 * list_entry - get the struct for this entry 140 * @ptr: the &struct list_head pointer. 141 * @type: the type of the struct this is embedded in. 142 * @member: the name of the list_struct within the struct. 143 */ 144#define list_entry(ptr, type, member) \ 145 ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) 146 147/** 148 * list_for_each - iterate over a list 149 * @pos: the &struct list_head to use as a loop counter. 150 * @n: another &struct list_head to use as temporary storage 151 * @head: the head for your list. 152 */ 153#define list_for_each(pos, head) \ 154 for (pos = (head)->next; pos != (head); \ 155 pos = pos->next) 156 157/** 158 * list_for_each_prev - iterate over a list in reverse order 159 * @pos: the &struct list_head to use as a loop counter. 160 * @head: the head for your list. 161 */ 162#define list_for_each_prev(pos, head) \ 163 for (pos = (head)->prev; pos != (head); \ 164 pos = pos->prev) 165#endif 166