diff options
Diffstat (limited to 'src/linkedlist.h')
| -rw-r--r-- | src/linkedlist.h | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/src/linkedlist.h b/src/linkedlist.h new file mode 100644 index 0000000..4f07927 --- /dev/null +++ b/src/linkedlist.h @@ -0,0 +1,295 @@ +/* + * Burrowed from the Linux kernel. + */ + +#ifndef _RATPOISON_LINKLIST_H +#define _RATPOISON_LINKLIST_H + +static inline void prefetch(const void *x) {;} + +/* + * Simple doubly linked list implementation. + * + * Some of the internal functions ("__xxx") are useful when + * manipulating whole lists rather than single entries, as + * sometimes we already know the next/prev entries and we can + * generate better code by using them directly rather than + * using the generic single-entry routines. + */ + +struct list_head { + struct list_head *next, *prev; +}; + +#define LIST_HEAD_INIT(name) { &(name), &(name) } + +#define LIST_HEAD(name) \ + struct list_head name = LIST_HEAD_INIT(name) + +#define INIT_LIST_HEAD(ptr) do { \ + (ptr)->next = (ptr); (ptr)->prev = (ptr); \ +} while (0) + +/* + * Insert a new entry between two known consecutive entries. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_add(struct list_head *new, + struct list_head *prev, + struct list_head *next) +{ + next->prev = new; + new->next = next; + new->prev = prev; + prev->next = new; +} + +/** + * list_add - add a new entry + * @new: new entry to be added + * @head: list head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ +static inline void list_add(struct list_head *new, struct list_head *head) +{ + __list_add(new, head, head->next); +} + +/** + * list_add_tail - add a new entry + * @new: new entry to be added + * @head: list head to add it before + * + * Insert a new entry before the specified head. + * This is useful for implementing queues. + */ +static inline void list_add_tail(struct list_head *new, struct list_head *head) +{ + __list_add(new, head->prev, head); +} + +/* + * Delete a list entry by making the prev/next entries + * point to each other. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_del(struct list_head * prev, struct list_head * next) +{ + next->prev = prev; + prev->next = next; +} + +/** + * list_del - deletes entry from list. + * @entry: the element to delete from the list. + * Note: list_empty on entry does not return true after this, the entry is + * in an undefined state. + */ +static inline void list_del(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); +} + +/** + * list_del_init - deletes entry from list and reinitialize it. + * @entry: the element to delete from the list. + */ +static inline void list_del_init(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + INIT_LIST_HEAD(entry); +} + +/** + * list_move - delete from one list and add as another's head + * @list: the entry to move + * @head: the head that will precede our entry + */ +static inline void list_move(struct list_head *list, struct list_head *head) +{ + __list_del(list->prev, list->next); + list_add(list, head); +} + +/** + * list_move_tail - delete from one list and add as another's tail + * @list: the entry to move + * @head: the head that will follow our entry + */ +static inline void list_move_tail(struct list_head *list, + struct list_head *head) +{ + __list_del(list->prev, list->next); + list_add_tail(list, head); +} + +/** + * list_empty - tests whether a list is empty + * @head: the list to test. + */ +static inline int list_empty(struct list_head *head) +{ + return head->next == head; +} + +static inline void __list_splice(struct list_head *list, + struct list_head *head) +{ + struct list_head *first = list->next; + struct list_head *last = list->prev; + struct list_head *at = head->next; + + first->prev = head; + head->next = first; + + last->next = at; + at->prev = last; +} + +/** + * list_splice - join two lists + * @list: the new list to add. + * @head: the place to add it in the first list. + */ +static inline void list_splice(struct list_head *list, struct list_head *head) +{ + if (!list_empty(list)) + __list_splice(list, head); +} + +/** + * list_splice_init - join two lists and reinitialise the emptied list. + * @list: the new list to add. + * @head: the place to add it in the first list. + * + * The list at @list is reinitialised + */ +static inline void list_splice_init(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) { + __list_splice(list, head); + INIT_LIST_HEAD(list); + } +} + +/** + * container_of - cast a member of a structure out to the containing structure + * + * @ptr: the pointer to the member. + * @type: the type of the container struct this is embedded in. + * @member: the name of the member within the struct. + * + */ +#define container_of(ptr, type, member) ({ \ + const typeof( ((type *)0)->member ) *__mptr = (ptr); \ + (type *)( (char *)__mptr - offsetof(type,member) );}) + +/** + * list_entry - get the struct for this entry + * @ptr: the &struct list_head pointer. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_struct within the struct. + */ +#define list_entry(ptr, type, member) \ + container_of(ptr, type, member) + + +/** + * __list_for_each - iterate over a list + * @pos: the &struct list_head to use as a loop counter. + * @head: the head for your list. + * + * This variant differs from list_for_each() in that it's the + * simplest possible list iteration code, no prefetching is done. + * Use this for code that knows the list to be very short (empty + * or 1 entry) most of the time. + */ +#define list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/** + * list_for_each_prev - iterate over a list backwards + * @pos: the &struct list_head to use as a loop counter. + * @head: the head for your list. + */ +#define list_for_each_prev(pos, head) \ + for (pos = (head)->prev, prefetch(pos->prev); pos != (head); \ + pos = pos->prev, prefetch(pos->prev)) + +/** + * list_for_each_safe - iterate over a list safe against removal of list entry + * @pos: the &struct list_head to use as a loop counter. + * @n: another &struct list_head to use as temporary storage + * @head: the head for your list. + */ +#define list_for_each_safe(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, n = pos->next) + +#define list_for_each_safe_entry(item, pos, n, head, member) \ + for (pos = (head)->next, \ + item = list_entry(pos, typeof(*item), member), \ + n = pos->next \ + ; \ + pos != (head) \ + ; \ + pos = n, \ + item = list_entry(pos, typeof(*item), member), \ + n = pos->next) \ + +/** + * list_for_each_entry - iterate over list of given type + * @pos: the type * to use as a loop counter. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry(pos, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member), \ + prefetch(pos->member.next); \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member), \ + prefetch(pos->member.next)) + +#define list_for_each_entry_safe(pos, n, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member), \ + n = list_entry(pos->member.next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = n, \ + n = list_entry(pos->member.next, typeof(*pos), member)) + +#define list_direction_entry(pos, head, member, direction) \ +({ \ + typeof(pos) ret = NULL; \ + struct list_head *a_head = head; \ + if (pos->member.direction == a_head) { \ + if (a_head->direction != &pos->member) \ + ret = list_entry(a_head->direction, \ + typeof(*pos), member); \ + } else { \ + ret = list_entry(pos->member.direction, \ + typeof(*pos), member); \ + } \ + ret; \ +}) + +#define list_next_entry(pos, head, member) \ + list_direction_entry(pos, head, member, next) + +#define list_prev_entry(pos, head, member) \ + list_direction_entry(pos, head, member, prev) + +#define list_for_each_entry_prev(pos, head, member) \ + for (pos = list_entry((head)->prev, typeof(*pos), member), \ + prefetch(pos->member.prev); \ + &pos->member != (head); \ + pos = list_entry(pos->member.prev, typeof(*pos), member), \ + prefetch(pos->member.prev)) + +#endif |