1 #if !defined(_BLKID_LIST_H) && !defined(LIST_HEAD_INIT) 2 #define _BLKID_LIST_H 3 4 #ifdef __cplusplus 5 extern "C" { 6 #endif 7 8 #ifdef HAVE_INTTYPES_H 9 #include <inttypes.h> 10 #else 11 #ifdef HAVE_STDINT_H 12 #include <stdint.h> 13 #endif 14 #endif 15 16 #ifdef __GNUC__ 17 #define _INLINE_ static __inline__ 18 #else /* For Watcom C */ 19 #define _INLINE_ static inline 20 #endif 21 22 /* 23 * Simple doubly linked list implementation. 24 * 25 * Some of the internal functions ("__xxx") are useful when 26 * manipulating whole lists rather than single entries, as 27 * sometimes we already know the next/prev entries and we can 28 * generate better code by using them directly rather than 29 * using the generic single-entry routines. 30 */ 31 32 struct list_head { 33 struct list_head *next, *prev; 34 }; 35 36 #define LIST_HEAD_INIT(name) { &(name), &(name) } 37 38 #define INIT_LIST_HEAD(ptr) do { \ 39 (ptr)->next = (ptr); (ptr)->prev = (ptr); \ 40 } while (0) 41 42 /* 43 * Insert a new entry between two known consecutive entries. 44 * 45 * This is only for internal list manipulation where we know 46 * the prev/next entries already! 47 */ 48 _INLINE_ void __list_add(struct list_head * add, 49 struct list_head * prev, 50 struct list_head * next) 51 { 52 next->prev = add; 53 add->next = next; 54 add->prev = prev; 55 prev->next = add; 56 } 57 58 /** 59 * list_add - add a new entry 60 * @add: new entry to be added 61 * @head: list head to add it after 62 * 63 * Insert a new entry after the specified head. 64 * This is good for implementing stacks. 65 */ 66 _INLINE_ void list_add(struct list_head *add, struct list_head *head) 67 { 68 __list_add(add, head, head->next); 69 } 70 71 /** 72 * list_add_tail - add a new entry 73 * @add: new entry to be added 74 * @head: list head to add it before 75 * 76 * Insert a new entry before the specified head. 77 * This is useful for implementing queues. 78 */ 79 _INLINE_ void list_add_tail(struct list_head *add, struct list_head *head) 80 { 81 __list_add(add, head->prev, head); 82 } 83 84 /* 85 * Delete a list entry by making the prev/next entries 86 * point to each other. 87 * 88 * This is only for internal list manipulation where we know 89 * the prev/next entries already! 90 */ 91 _INLINE_ void __list_del(struct list_head * prev, 92 struct list_head * next) 93 { 94 next->prev = prev; 95 prev->next = next; 96 } 97 98 /** 99 * list_del - deletes entry from list. 100 * @entry: the element to delete from the list. 101 * 102 * list_empty() on @entry does not return true after this, @entry is 103 * in an undefined state. 104 */ 105 _INLINE_ void list_del(struct list_head *entry) 106 { 107 __list_del(entry->prev, entry->next); 108 } 109 110 /** 111 * list_del_init - deletes entry from list and reinitialize it. 112 * @entry: the element to delete from the list. 113 */ 114 _INLINE_ void list_del_init(struct list_head *entry) 115 { 116 __list_del(entry->prev, entry->next); 117 INIT_LIST_HEAD(entry); 118 } 119 120 /** 121 * list_empty - tests whether a list is empty 122 * @head: the list to test. 123 */ 124 _INLINE_ int list_empty(struct list_head *head) 125 { 126 return head->next == head; 127 } 128 129 /** 130 * list_splice - join two lists 131 * @list: the new list to add. 132 * @head: the place to add it in the first list. 133 */ 134 _INLINE_ void list_splice(struct list_head *list, struct list_head *head) 135 { 136 struct list_head *first = list->next; 137 138 if (first != list) { 139 struct list_head *last = list->prev; 140 struct list_head *at = head->next; 141 142 first->prev = head; 143 head->next = first; 144 145 last->next = at; 146 at->prev = last; 147 } 148 } 149 150 /** 151 * list_entry - get the struct for this entry 152 * @ptr: the &struct list_head pointer. 153 * @type: the type of the struct this is embedded in. 154 * @member: the name of the list_struct within the struct. 155 */ 156 #define list_entry(ptr, type, member) \ 157 ((type *)((char *)(ptr)-(unsigned long)(intptr_t)(&((type *)0)->member))) 158 159 /** 160 * list_for_each - iterate over elements in a list 161 * @pos: the &struct list_head to use as a loop counter. 162 * @head: the head for your list. 163 */ 164 #define list_for_each(pos, head) \ 165 for (pos = (head)->next; pos != (head); pos = pos->next) 166 167 /** 168 * list_for_each_safe - iterate over elements in a list, but don't dereference 169 * pos after the body is done (in case it is freed) 170 * @pos: the &struct list_head to use as a loop counter. 171 * @pnext: the &struct list_head to use as a pointer to the next item. 172 * @head: the head for your list (not included in iteration). 173 */ 174 #define list_for_each_safe(pos, pnext, head) \ 175 for (pos = (head)->next, pnext = pos->next; pos != (head); \ 176 pos = pnext, pnext = pos->next) 177 178 #undef _INLINE_ 179 180 #ifdef __cplusplus 181 } 182 #endif 183 184 #endif /* _BLKID_LIST_H */ 185
