list.h

   1 /*
   2  * Copied from the Linux kernel source tree, version 2.6.0-test1.
   3  *
   4  * Licensed under the GPL v2 as per the whole kernel source tree.
   5  *
   6  */
   7
   8 #ifndef _LIST_H
   9 #define _LIST_H
  10
  11 /**
  12  * container_of - cast a member of a structure out to the containing structure
  13  *
  14  * @ptr:        the pointer to the member.
  15  * @type:       the type of the container struct this is embedded in.
  16  * @member:     the name of the member within the struct.
  17  *
  18  */
  19 #define container_of(ptr, type, member) ({                      \
  20         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
  21         (type *)( (char *)__mptr - offsetof(type,member) );})
  22
  23 /*
  24  * These are non-NULL pointers that will result in page faults
  25  * under normal circumstances, used to verify that nobody uses
  26  * non-initialized list entries.
  27  */
  28 #define LIST_POISON1  ((void *) 0x00100100)
  29 #define LIST_POISON2  ((void *) 0x00200200)
  30
  31 /*
  32  * Simple doubly linked list implementation.
  33  *
  34  * Some of the internal functions ("__xxx") are useful when
  35  * manipulating whole lists rather than single entries, as
  36  * sometimes we already know the next/prev entries and we can
  37  * generate better code by using them directly rather than
  38  * using the generic single-entry routines.
  39  */
  40
  41 struct list_head {
  42         struct list_head *next, *prev;
  43 };
  44
  45 #define LIST_HEAD_INIT(name) { &(name), &(name) }
  46
  47 #define LIST_HEAD(name) \
  48         struct list_head name = LIST_HEAD_INIT(name)
  49
  50 #define INIT_LIST_HEAD(ptr) do { \
  51         (ptr)->next = (ptr); (ptr)->prev = (ptr); \
  52 } while (0)
  53
  54 /*
  55  * Insert a new entry between two known consecutive entries.
  56  *
  57  * This is only for internal list manipulation where we know
  58  * the prev/next entries already!
  59  */
  60 static inline void __list_add(struct list_head *new,
  61                               struct list_head *prev,
  62                               struct list_head *next)
  63 {
  64         next->prev = new;
  65         new->next = next;
  66         new->prev = prev;
  67         prev->next = new;
  68 }
  69
  70 /**
  71  * list_add - add a new entry
  72  * @new: new entry to be added
  73  * @head: list head to add it after
  74  *
  75  * Insert a new entry after the specified head.
  76  * This is good for implementing stacks.
  77  */
  78 static inline void list_add(struct list_head *new, struct list_head *head)
  79 {
  80         __list_add(new, head, head->next);
  81 }
  82
  83 /**
  84  * list_add_tail - add a new entry
  85  * @new: new entry to be added
  86  * @head: list head to add it before
  87  *
  88  * Insert a new entry before the specified head.
  89  * This is useful for implementing queues.
  90  */
  91 static inline void list_add_tail(struct list_head *new, struct list_head *head)
  92 {
  93         __list_add(new, head->prev, head);
  94 }
  95
  96 /*
  97  * Delete a list entry by making the prev/next entries
  98  * point to each other.
  99  *
 100  * This is only for internal list manipulation where we know
 101  * the prev/next entries already!
 102  */
 103 static inline void __list_del(struct list_head * prev, struct list_head * next)
 104 {
 105         next->prev = prev;
 106         prev->next = next;
 107 }
 108
 109 /**
 110  * list_del - deletes entry from list.
 111  * @entry: the element to delete from the list.
 112  * Note: list_empty on entry does not return true after this, the entry is
 113  * in an undefined state.
 114  */
 115 static inline void list_del(struct list_head *entry)
 116 {
 117         __list_del(entry->prev, entry->next);
 118         entry->next = LIST_POISON1;
 119         entry->prev = LIST_POISON2;
 120 }
 121
 122 /**
 123  * list_del_init - deletes entry from list and reinitialize it.
 124  * @entry: the element to delete from the list.
 125  */
 126 static inline void list_del_init(struct list_head *entry)
 127 {
 128         __list_del(entry->prev, entry->next);
 129         INIT_LIST_HEAD(entry);
 130 }
 131
 132 /**
 133  * list_move - delete from one list and add as another's head
 134  * @list: the entry to move
 135  * @head: the head that will precede our entry
 136  */
 137 static inline void list_move(struct list_head *list, struct list_head *head)
 138 {
 139         __list_del(list->prev, list->next);
 140         list_add(list, head);
 141 }
 142
 143 /**
 144  * list_move_tail - delete from one list and add as another's tail
 145  * @list: the entry to move
 146  * @head: the head that will follow our entry
 147  */
 148 static inline void list_move_tail(struct list_head *list,
 149                                   struct list_head *head)
 150 {
 151         __list_del(list->prev, list->next);
 152         list_add_tail(list, head);
 153 }
 154
 155 /**
 156  * list_empty - tests whether a list is empty
 157  * @head: the list to test.
 158  */
 159 static inline int list_empty(struct list_head *head)
 160 {
 161         return head->next == head;
 162 }
 163
 164 static inline void __list_splice(struct list_head *list,
 165                                  struct list_head *head)
 166 {
 167         struct list_head *first = list->next;
 168         struct list_head *last = list->prev;
 169         struct list_head *at = head->next;
 170
 171         first->prev = head;
 172         head->next = first;
 173
 174         last->next = at;
 175         at->prev = last;
 176 }
 177
 178 /**
 179  * list_splice - join two lists
 180  * @list: the new list to add.
 181  * @head: the place to add it in the first list.
 182  */
 183 static inline void list_splice(struct list_head *list, struct list_head *head)
 184 {
 185         if (!list_empty(list))
 186                 __list_splice(list, head);
 187 }
 188
 189 /**
 190  * list_splice_init - join two lists and reinitialise the emptied list.
 191  * @list: the new list to add.
 192  * @head: the place to add it in the first list.
 193  *
 194  * The list at @list is reinitialised
 195  */
 196 static inline void list_splice_init(struct list_head *list,
 197                                     struct list_head *head)
 198 {
 199         if (!list_empty(list)) {
 200                 __list_splice(list, head);
 201                 INIT_LIST_HEAD(list);
 202         }
 203 }
 204
 205 /**
 206  * list_entry - get the struct for this entry
 207  * @ptr:        the &struct list_head pointer.
 208  * @type:       the type of the struct this is embedded in.
 209  * @member:     the name of the list_struct within the struct.
 210  */
 211 #define list_entry(ptr, type, member) \
 212         container_of(ptr, type, member)
 213
 214 /**
 215  * list_for_each        -       iterate over a list
 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(pos, head) \
 220         for (pos = (head)->next; pos != (head); \
 221                 pos = pos->next)
 222
 223 /**
 224  * __list_for_each      -       iterate over a list
 225  * @pos:        the &struct list_head to use as a loop counter.
 226  * @head:       the head for your list.
 227  *
 228  * This variant differs from list_for_each() in that it's the
 229  * simplest possible list iteration code.
 230  * Use this for code that knows the list to be very short (empty
 231  * or 1 entry) most of the time.
 232  */
 233 #define __list_for_each(pos, head) \
 234         for (pos = (head)->next; pos != (head); pos = pos->next)
 235
 236 /**
 237  * list_for_each_prev   -       iterate over a list backwards
 238  * @pos:        the &struct list_head to use as a loop counter.
 239  * @head:       the head for your list.
 240  */
 241 #define list_for_each_prev(pos, head) \
 242         for (pos = (head)->prev; pos != (head); pos = pos->prev)
 243
 244 /**
 245  * list_for_each_safe   -       iterate over a list safe against removal of list entry
 246  * @pos:        the &struct list_head to use as a loop counter.
 247  * @n:          another &struct list_head to use as temporary storage
 248  * @head:       the head for your list.
 249  */
 250 #define list_for_each_safe(pos, n, head) \
 251         for (pos = (head)->next, n = pos->next; pos != (head); \
 252                 pos = n, n = pos->next)
 253
 254 /**
 255  * list_for_each_entry  -       iterate over list of given type
 256  * @pos:        the type * to use as a loop counter.
 257  * @head:       the head for your list.
 258  * @member:     the name of the list_struct within the struct.
 259  */
 260 #define list_for_each_entry(pos, head, member)                          \
 261         for (pos = list_entry((head)->next, typeof(*pos), member);      \
 262              &pos->member != (head);                                    \
 263              pos = list_entry(pos->member.next, typeof(*pos), member))
 264
 265 /**
 266  * list_for_each_entry_reverse - iterate backwards over list of given type.
 267  * @pos:        the type * to use as a loop counter.
 268  * @head:       the head for your list.
 269  * @member:     the name of the list_struct within the struct.
 270  */
 271 #define list_for_each_entry_reverse(pos, head, member)                  \
 272         for (pos = list_entry((head)->prev, typeof(*pos), member);      \
 273              &pos->member != (head);                                    \
 274              pos = list_entry(pos->member.prev, typeof(*pos), member))
 275
 276 /**
 277  * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
 278  * @pos:        the type * to use as a loop counter.
 279  * @n:          another type * to use as temporary storage
 280  * @head:       the head for your list.
 281  * @member:     the name of the list_struct within the struct.
 282  */
 283 #define list_for_each_entry_safe(pos, n, head, member)                  \
 284         for (pos = list_entry((head)->next, typeof(*pos), member),      \
 285                 n = list_entry(pos->member.next, typeof(*pos), member); \
 286              &pos->member != (head);                                    \
 287              pos = n, n = list_entry(n->member.next, typeof(*n), member))
 288
 289 #endif /* _LIST_H */