reactos/drivers/filesystems/ext2/inc/linux/list.h

   1 #ifndef __LINUX_LIST_H__
   2 #define __LINUX_LIST_H__
   3
   4 /*
   5  * Simple doubly linked list implementation.
   6  *
   7  * Some of the internal functions ("__xxx") are useful when
   8  * manipulating whole lists rather than single entries, as
   9  * sometimes we already know the next/prev entries and we can
  10  * generate better code by using them directly rather than
  11  * using the generic single-entry routines.
  12  */
  13
  14 #define prefetch(a) ((void *)a)
  15
  16 struct list_head {
  17     struct list_head *next, *prev;
  18 };
  19
  20 #define LIST_HEAD_INIT(name) { &(name), &(name) }
  21
  22 #define LIST_HEAD(name) \
  23         struct list_head name = LIST_HEAD_INIT(name)
  24
  25 static inline void INIT_LIST_HEAD(struct list_head *list)
  26 {
  27     list->next = list;
  28     list->prev = list;
  29 }
  30
  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  */
  37 static 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  */
  55 static 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  */
  68 static 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  */
  80 static inline void __list_del(struct list_head * prev, struct list_head * next)
  81 {
  82     next->prev = prev;
  83     prev->next = next;
  84 }
  85
  86 /**
  87  * list_del - deletes entry from list.
  88  * @entry: the element to delete from the list.
  89  * Note: list_empty on entry does not return true after this, the entry is in an undefined state.
  90  */
  91 static inline void list_del(struct list_head *entry)
  92 {
  93     __list_del(entry->prev, entry->next);
  94 }
  95
  96 /**
  97  * list_del_init - deletes entry from list and reinitialize it.
  98  * @entry: the element to delete from the list.
  99  */
 100 static inline void list_del_init(struct list_head *entry)
 101 {
 102     __list_del(entry->prev, entry->next);
 103     INIT_LIST_HEAD(entry);
 104 }
 105
 106 /**
 107  * list_move - delete from one list and add as another's head
 108  * @list: the entry to move
 109  * @head: the head that will precede our entry
 110  */
 111 static inline void list_move(struct list_head *list, struct list_head *head)
 112 {
 113     __list_del(list->prev, list->next);
 114     list_add(list, head);
 115 }
 116
 117 /**
 118  * list_move_tail - delete from one list and add as another's tail
 119  * @list: the entry to move
 120  * @head: the head that will follow our entry
 121  */
 122 static inline void list_move_tail(struct list_head *list,
 123                                   struct list_head *head)
 124 {
 125     __list_del(list->prev, list->next);
 126     list_add_tail(list, head);
 127 }
 128
 129 /**
 130  * list_empty - tests whether a list is empty
 131  * @head: the list to test.
 132  */
 133 static inline int list_empty(struct list_head *head)
 134 {
 135     return head->next == head;
 136 }
 137
 138 static inline int list_empty_careful(const struct list_head *head)
 139 {
 140     struct list_head *next = head->next;
 141     return (next == head) && (next == head->prev);
 142 }
 143
 144 static inline void __list_splice(struct list_head *list,
 145                                  struct list_head *head)
 146 {
 147     struct list_head *first = list->next;
 148     struct list_head *last = list->prev;
 149     struct list_head *at = head->next;
 150
 151     first->prev = head;
 152     head->next = first;
 153
 154     last->next = at;
 155     at->prev = last;
 156 }
 157
 158 /**
 159  * list_splice - join two lists
 160  * @list: the new list to add.
 161  * @head: the place to add it in the first list.
 162  */
 163 static inline void list_splice(struct list_head *list, struct list_head *head)
 164 {
 165     if (!list_empty(list))
 166         __list_splice(list, head);
 167 }
 168
 169 /**
 170  * list_splice_init - join two lists and reinitialise the emptied list.
 171  * @list: the new list to add.
 172  * @head: the place to add it in the first list.
 173  *
 174  * The list at @list is reinitialised
 175  */
 176 static inline void list_splice_init(struct list_head *list,
 177                                     struct list_head *head)
 178 {
 179     if (!list_empty(list)) {
 180         __list_splice(list, head);
 181         INIT_LIST_HEAD(list);
 182     }
 183 }
 184
 185 /**
 186  * list_entry - get the struct for this entry
 187  * @ptr:        the &struct list_head pointer.
 188  * @type:       the type of the struct this is embedded in.
 189  * @member:     the name of the list_struct within the struct.
 190  */
 191 #define list_entry(ptr, type, member) \
 192         ((type *)((char *)(ptr)-(char *)(&((type *)0)->member)))
 193
 194 /**
 195  * list_for_each        -       iterate over a list
 196  * @pos:        the &struct list_head to use as a loop counter.
 197  * @head:       the head for your list.
 198  */
 199 #define list_for_each(pos, head) \
 200         for (pos = (head)->next, prefetch(pos->next); pos != (head); \
 201                 pos = pos->next, prefetch(pos->next))
 202
 203 /**
 204  * list_for_each_safe   -       iterate over a list safe against removal of list entry
 205  * @pos:        the &struct list_head to use as a loop counter.
 206  * @n:          another &struct list_head to use as temporary storage
 207  * @head:       the head for your list.
 208  */
 209 #define list_for_each_safe(pos, n, head) \
 210         for (pos = (head)->next, n = pos->next; pos != (head); \
 211                 pos = n, n = pos->next)
 212
 213 #ifndef list_for_each_prev
 214 /**
 215  * list_for_each_prev   -       iterate over a list in reverse order
 216  * @pos:        the &struct list_head to use as a loop counter.
 217  * @head:       the head for your list.
 218  */
 219 #define list_for_each_prev(pos, head) \
 220         for (pos = (head)->prev, prefetch(pos->prev); pos != (head); \
 221                 pos = pos->prev, prefetch(pos->prev))
 222
 223 #endif /* list_for_each_prev */
 224
 225 #ifndef list_for_each_entry
 226 /**
 227  * list_for_each_entry  -       iterate over list of given type
 228  * @pos:        the type * to use as a loop counter.
 229  * @head:       the head for your list.
 230  * @member:     the name of the list_struct within the struct.
 231  */
 232 #define list_for_each_entry(pos, head, type, member)            \
 233         for (pos = list_entry((head)->next, type, member),      \
 234                      prefetch(pos->member.next);                        \
 235              &pos->member != (head);                                    \
 236              pos = list_entry(pos->member.next, type, member),  \
 237              prefetch(pos->member.next))
 238 #endif /* list_for_each_entry */
 239
 240 #ifndef list_for_each_entry_safe
 241 /**
 242  * list_for_each_entry_safe  -       iterate over list of given type safe against removal of list entry
 243  * @pos:        the type * to use as a loop counter.
 244  * @n:          another type * to use as temporary storage
 245  * @head:       the head for your list.
 246  * @member:     the name of the list_struct within the struct.
 247  */
 248 #define list_for_each_entry_safe(pos, n, head, type, member)                    \
 249         for (pos = list_entry((head)->next, type, member),      \
 250                 n = list_entry(pos->member.next, type, member); \
 251              &pos->member != (head);                                    \
 252              pos = n, n = list_entry(n->member.next, type, member))
 253 #endif /* list_for_each_entry_safe */
 254
 255 #endif /* __LINUX_LIST_H__ */