diff options
Diffstat (limited to 'libblkid/list.h')
-rw-r--r-- | libblkid/list.h | 340 |
1 files changed, 0 insertions, 340 deletions
diff --git a/libblkid/list.h b/libblkid/list.h deleted file mode 100644 index 7b6067239..000000000 --- a/libblkid/list.h +++ /dev/null @@ -1,340 +0,0 @@ -/* - * Copyright (C) 2008 Karel Zak <kzak@redhat.com> - * Copyright (C) 1999-2008 by Theodore Ts'o - * - * This file may be redistributed under the terms of the - * GNU Lesser General Public License. - * - * (based on list.h from e2fsprogs) - * Merge sort based on kernel's implementation. - */ - -#ifndef UTIL_LINUX_LIST_H -#define UTIL_LINUX_LIST_H - -/* TODO: use AC_C_INLINE */ -#ifdef __GNUC__ -#define _INLINE_ static __inline__ -#else /* For Watcom C */ -#define _INLINE_ static inline -#endif - -/* - * 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! - */ -_INLINE_ void __list_add(struct list_head * add, - struct list_head * prev, - struct list_head * next) -{ - next->prev = add; - add->next = next; - add->prev = prev; - prev->next = add; -} - -/** - * list_add - add a new entry - * @add: 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. - */ -_INLINE_ void list_add(struct list_head *add, struct list_head *head) -{ - __list_add(add, head, head->next); -} - -/** - * list_add_tail - add a new entry - * @add: 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. - */ -_INLINE_ void list_add_tail(struct list_head *add, struct list_head *head) -{ - __list_add(add, 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! - */ -_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. - * - * list_empty() on @entry does not return true after this, @entry is - * in an undefined state. - */ -_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. - */ -_INLINE_ void list_del_init(struct list_head *entry) -{ - __list_del(entry->prev, entry->next); - INIT_LIST_HEAD(entry); -} - -/** - * list_empty - tests whether a list is empty - * @head: the list to test. - */ -_INLINE_ int list_empty(struct list_head *head) -{ - return head->next == head; -} - -/** - * list_entry_is_last - tests whether is entry last in the list - * @entry: the entry to test. - * @head: the list to test. - */ -_INLINE_ int list_entry_is_last(struct list_head *entry, struct list_head *head) -{ - return head->prev == entry; -} - -/** - * list_splice - join two lists - * @list: the new list to add. - * @head: the place to add it in the first list. - */ -_INLINE_ void list_splice(struct list_head *list, struct list_head *head) -{ - struct list_head *first = list->next; - - if (first != list) { - 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_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) ({ \ - const typeof( ((type *)0)->member ) *__mptr = (ptr); \ - (type *)( (char *)__mptr - offsetof(type,member) );}) - - -#define list_first_entry(head, type, member) \ - ((head) && (head)->next != (head) ? list_entry((head)->next, type, member) : NULL) - -#define list_last_entry(head, type, member) \ - ((head) && (head)->prev != (head) ? list_entry((head)->prev, type, member) : NULL) - -/** - * list_for_each - iterate over elements in a list - * @pos: the &struct list_head to use as a loop counter. - * @head: the head for your list. - */ -#define list_for_each(pos, head) \ - for (pos = (head)->next; pos != (head); pos = pos->next) - -/** - * list_for_each_backwardly - iterate over elements in a list in reverse - * @pos: the &struct list_head to use as a loop counter. - * @head: the head for your list. - */ -#define list_for_each_backwardly(pos, head) \ - for (pos = (head)->prev; pos != (head); pos = pos->prev) - -/** - * list_for_each_safe - iterate over elements in a list, but don't dereference - * pos after the body is done (in case it is freed) - * @pos: the &struct list_head to use as a loop counter. - * @pnext: the &struct list_head to use as a pointer to the next item. - * @head: the head for your list (not included in iteration). - */ -#define list_for_each_safe(pos, pnext, head) \ - for (pos = (head)->next, pnext = pos->next; pos != (head); \ - pos = pnext, pnext = pos->next) - -#define MAX_LIST_LENGTH_BITS 20 - -/* - * Returns a list organized in an intermediate format suited - * to chaining of merge() calls: null-terminated, no reserved or - * sentinel head node, "prev" links not maintained. - */ -_INLINE_ struct list_head *merge(int (*cmp)(struct list_head *a, - struct list_head *b), - struct list_head *a, struct list_head *b) -{ - struct list_head head, *tail = &head; - - while (a && b) { - /* if equal, take 'a' -- important for sort stability */ - if ((*cmp)(a, b) <= 0) { - tail->next = a; - a = a->next; - } else { - tail->next = b; - b = b->next; - } - tail = tail->next; - } - tail->next = a ? a : b; - return head.next; -} - -/* - * Combine final list merge with restoration of standard doubly-linked - * list structure. This approach duplicates code from merge(), but - * runs faster than the tidier alternatives of either a separate final - * prev-link restoration pass, or maintaining the prev links - * throughout. - */ -_INLINE_ void merge_and_restore_back_links(int (*cmp)(struct list_head *a, - struct list_head *b), - struct list_head *head, - struct list_head *a, struct list_head *b) -{ - struct list_head *tail = head; - - while (a && b) { - /* if equal, take 'a' -- important for sort stability */ - if ((*cmp)(a, b) <= 0) { - tail->next = a; - a->prev = tail; - a = a->next; - } else { - tail->next = b; - b->prev = tail; - b = b->next; - } - tail = tail->next; - } - tail->next = a ? a : b; - - do { - /* - * In worst cases this loop may run many iterations. - * Continue callbacks to the client even though no - * element comparison is needed, so the client's cmp() - * routine can invoke cond_resched() periodically. - */ - (*cmp)(tail->next, tail->next); - - tail->next->prev = tail; - tail = tail->next; - } while (tail->next); - - tail->next = head; - head->prev = tail; -} - - -/** - * list_sort - sort a list - * @head: the list to sort - * @cmp: the elements comparison function - * - * This function implements "merge sort", which has O(nlog(n)) - * complexity. - * - * The comparison function @cmp must return a negative value if @a - * should sort before @b, and a positive value if @a should sort after - * @b. If @a and @b are equivalent, and their original relative - * ordering is to be preserved, @cmp must return 0. - */ -_INLINE_ void list_sort(struct list_head *head, - int (*cmp)(struct list_head *a, - struct list_head *b)) -{ - struct list_head *part[MAX_LIST_LENGTH_BITS+1]; /* sorted partial lists - -- last slot is a sentinel */ - size_t lev; /* index into part[] */ - size_t max_lev = 0; - struct list_head *list; - - if (list_empty(head)) - return; - - memset(part, 0, sizeof(part)); - - head->prev->next = NULL; - list = head->next; - - while (list) { - struct list_head *cur = list; - list = list->next; - cur->next = NULL; - - for (lev = 0; part[lev]; lev++) { - cur = merge(cmp, part[lev], cur); - part[lev] = NULL; - } - if (lev > max_lev) { - /* list passed to list_sort() too long for efficiency */ - if (lev >= ARRAY_SIZE(part) - 1) - lev--; - max_lev = lev; - } - part[lev] = cur; - } - - for (lev = 0; lev < max_lev; lev++) - if (part[lev]) - list = merge(cmp, part[lev], list); - - merge_and_restore_back_links(cmp, head, part[max_lev], list); -} - -#undef _INLINE_ - -#endif /* UTIL_LINUX_LIST_H */ |