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204 lines
6.4 KiB
C
204 lines
6.4 KiB
C
/*
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* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
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* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License v.2.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _LVM_LIST_H
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#define _LVM_LIST_H
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#include <assert.h>
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/*
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* A list consists of a list head plus elements.
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* Each element has 'next' and 'previous' pointers.
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* The list head's pointers point to the first and the last element.
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*/
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struct list {
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struct list *n, *p;
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};
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/*
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* Initialise a list before use.
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* The list head's next and previous pointers point back to itself.
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*/
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#define LIST_INIT(name) struct list name = { &(name), &(name) }
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void list_init(struct list *head);
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/*
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* Insert an element before 'head'.
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* If 'head' is the list head, this adds an element to the end of the list.
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*/
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void list_add(struct list *head, struct list *elem);
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/*
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* Insert an element after 'head'.
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* If 'head' is the list head, this adds an element to the front of the list.
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*/
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void list_add_h(struct list *head, struct list *elem);
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/*
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* Delete an element from its list.
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* Note that this doesn't change the element itself - it may still be safe
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* to follow its pointers.
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*/
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void list_del(struct list *elem);
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/*
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* Is the list empty?
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*/
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int list_empty(const struct list *head);
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/*
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* Is this the first element of the list?
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*/
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int list_start(const struct list *head, const struct list *elem);
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/*
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* Is this the last element of the list?
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*/
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int list_end(const struct list *head, const struct list *elem);
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/*
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* Return first element of the list or NULL if empty
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*/
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struct list *list_first(const struct list *head);
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/*
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* Return last element of the list or NULL if empty
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*/
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struct list *list_last(const struct list *head);
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/*
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* Return the previous element of the list, or NULL if we've reached the start.
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*/
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struct list *list_prev(const struct list *head, const struct list *elem);
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/*
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* Return the next element of the list, or NULL if we've reached the end.
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*/
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struct list *list_next(const struct list *head, const struct list *elem);
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/*
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* Given the address v of an instance of 'struct list' called 'head'
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* contained in a structure of type t, return the containing structure.
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*/
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#define list_struct_base(v, t, head) \
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((t *)((uintptr_t)(v) - (uintptr_t)&((t *) 0)->head))
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/*
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* Given the address v of an instance of 'struct list list' contained in
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* a structure of type t, return the containing structure.
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*/
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#define list_item(v, t) list_struct_base((v), t, list)
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/*
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* Given the address v of one known element e in a known structure of type t,
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* return another element f.
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*/
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#define struct_field(v, t, e, f) \
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(((t *)((uintptr_t)(v) - (uintptr_t)&((t *) 0)->e))->f)
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/*
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* Given the address v of a known element e in a known structure of type t,
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* return the list head 'list'
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*/
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#define list_head(v, t, e) struct_field(v, t, e, list)
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/*
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* Set v to each element of a list in turn.
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*/
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#define list_iterate(v, head) \
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for (v = (head)->n; v != head; v = v->n)
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/*
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* Set v to each element in a list in turn, starting from the element
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* in front of 'start'.
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* You can use this to 'unwind' a list_iterate and back out actions on
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* already-processed elements.
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* If 'start' is 'head' it walks the list backwards.
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*/
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#define list_uniterate(v, head, start) \
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for (v = (start)->p; v != head; v = v->p)
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/*
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* A safe way to walk a list and delete and free some elements along
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* the way.
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* t must be defined as a temporary variable of the same type as v.
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*/
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#define list_iterate_safe(v, t, head) \
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for (v = (head)->n, t = v->n; v != head; v = t, t = v->n)
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/*
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* Walk a list, setting 'v' in turn to the containing structure of each item.
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* The containing structure should be the same type as 'v'.
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* The 'struct list' variable within the containing structure is 'field'.
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*/
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#define list_iterate_items_gen(v, head, field) \
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for (v = list_struct_base((head)->n, typeof(*v), field); \
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&v->field != (head); \
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v = list_struct_base(v->field.n, typeof(*v), field))
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/*
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* Walk a list, setting 'v' in turn to the containing structure of each item.
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* The containing structure should be the same type as 'v'.
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* The list should be 'struct list list' within the containing structure.
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*/
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#define list_iterate_items(v, head) list_iterate_items_gen(v, (head), list)
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/*
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* Walk a list, setting 'v' in turn to the containing structure of each item.
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* The containing structure should be the same type as 'v'.
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* The 'struct list' variable within the containing structure is 'field'.
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* t must be defined as a temporary variable of the same type as v.
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*/
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#define list_iterate_items_gen_safe(v, t, head, field) \
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for (v = list_struct_base((head)->n, typeof(*v), field), \
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t = list_struct_base(v->field.n, typeof(*v), field); \
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&v->field != (head); \
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v = t, t = list_struct_base(v->field.n, typeof(*v), field))
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/*
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* Walk a list, setting 'v' in turn to the containing structure of each item.
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* The containing structure should be the same type as 'v'.
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* The list should be 'struct list list' within the containing structure.
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* t must be defined as a temporary variable of the same type as v.
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*/
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#define list_iterate_items_safe(v, t, head) \
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list_iterate_items_gen_safe(v, t, (head), list)
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/*
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* Walk a list backwards, setting 'v' in turn to the containing structure
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* of each item.
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* The containing structure should be the same type as 'v'.
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* The 'struct list' variable within the containing structure is 'field'.
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*/
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#define list_iterate_back_items_gen(v, head, field) \
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for (v = list_struct_base((head)->p, typeof(*v), field); \
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&v->field != (head); \
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v = list_struct_base(v->field.p, typeof(*v), field))
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/*
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* Walk a list backwards, setting 'v' in turn to the containing structure
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* of each item.
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* The containing structure should be the same type as 'v'.
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* The list should be 'struct list list' within the containing structure.
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*/
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#define list_iterate_back_items(v, head) list_iterate_back_items_gen(v, (head), list)
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/*
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* Return the number of elements in a list by walking it.
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*/
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unsigned int list_size(const struct list *head);
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#endif
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