/* $NetBSD: list.h,v 1.1.1.1 2008/12/22 00:18:36 haad Exp $ */ /* * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved. * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved. * * This file is part of LVM2. * * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions * of the GNU Lesser General Public License v.2.1. * * You should have received a copy of the GNU Lesser General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifndef _LVM_LIST_H #define _LVM_LIST_H #include /* * A list consists of a list head plus elements. * Each element has 'next' and 'previous' pointers. * The list head's pointers point to the first and the last element. */ struct dm_list { struct dm_list *n, *p; }; /* * Initialise a list before use. * The list head's next and previous pointers point back to itself. */ #define DM_LIST_INIT(name) struct dm_list name = { &(name), &(name) } void dm_list_init(struct dm_list *head); /* * Insert an element before 'head'. * If 'head' is the list head, this adds an element to the end of the list. */ void dm_list_add(struct dm_list *head, struct dm_list *elem); /* * Insert an element after 'head'. * If 'head' is the list head, this adds an element to the front of the list. */ void dm_list_add_h(struct dm_list *head, struct dm_list *elem); /* * Delete an element from its list. * Note that this doesn't change the element itself - it may still be safe * to follow its pointers. */ void dm_list_del(struct dm_list *elem); /* * Remove an element from existing list and insert before 'head'. */ void dm_list_move(struct dm_list *head, struct dm_list *elem); /* * Is the list empty? */ int dm_list_empty(const struct dm_list *head); /* * Is this the first element of the list? */ int dm_list_start(const struct dm_list *head, const struct dm_list *elem); /* * Is this the last element of the list? */ int dm_list_end(const struct dm_list *head, const struct dm_list *elem); /* * Return first element of the list or NULL if empty */ struct dm_list *dm_list_first(const struct dm_list *head); /* * Return last element of the list or NULL if empty */ struct dm_list *dm_list_last(const struct dm_list *head); /* * Return the previous element of the list, or NULL if we've reached the start. */ struct dm_list *dm_list_prev(const struct dm_list *head, const struct dm_list *elem); /* * Return the next element of the list, or NULL if we've reached the end. */ struct dm_list *dm_list_next(const struct dm_list *head, const struct dm_list *elem); /* * Given the address v of an instance of 'struct dm_list' called 'head' * contained in a structure of type t, return the containing structure. */ #define dm_list_struct_base(v, t, head) \ ((t *)((uintptr_t)(v) - (uintptr_t)&((t *) 0)->head)) /* * Given the address v of an instance of 'struct dm_list list' contained in * a structure of type t, return the containing structure. */ #define dm_list_item(v, t) dm_list_struct_base((v), t, list) /* * Given the address v of one known element e in a known structure of type t, * return another element f. */ #define dm_struct_field(v, t, e, f) \ (((t *)((uintptr_t)(v) - (uintptr_t)&((t *) 0)->e))->f) /* * Given the address v of a known element e in a known structure of type t, * return the list head 'list' */ #define dm_list_head(v, t, e) dm_struct_field(v, t, e, list) /* * Set v to each element of a list in turn. */ #define dm_list_iterate(v, head) \ for (v = (head)->n; v != head; v = v->n) /* * Set v to each element in a list in turn, starting from the element * in front of 'start'. * You can use this to 'unwind' a list_iterate and back out actions on * already-processed elements. * If 'start' is 'head' it walks the list backwards. */ #define dm_list_uniterate(v, head, start) \ for (v = (start)->p; v != head; v = v->p) /* * A safe way to walk a list and delete and free some elements along * the way. * t must be defined as a temporary variable of the same type as v. */ #define dm_list_iterate_safe(v, t, head) \ for (v = (head)->n, t = v->n; v != head; v = t, t = v->n) /* * Walk a list, setting 'v' in turn to the containing structure of each item. * The containing structure should be the same type as 'v'. * The 'struct dm_list' variable within the containing structure is 'field'. */ #define dm_list_iterate_items_gen(v, head, field) \ for (v = dm_list_struct_base((head)->n, typeof(*v), field); \ &v->field != (head); \ v = dm_list_struct_base(v->field.n, typeof(*v), field)) /* * Walk a list, setting 'v' in turn to the containing structure of each item. * The containing structure should be the same type as 'v'. * The list should be 'struct dm_list list' within the containing structure. */ #define dm_list_iterate_items(v, head) dm_list_iterate_items_gen(v, (head), list) /* * Walk a list, setting 'v' in turn to the containing structure of each item. * The containing structure should be the same type as 'v'. * The 'struct dm_list' variable within the containing structure is 'field'. * t must be defined as a temporary variable of the same type as v. */ #define dm_list_iterate_items_gen_safe(v, t, head, field) \ for (v = dm_list_struct_base((head)->n, typeof(*v), field), \ t = dm_list_struct_base(v->field.n, typeof(*v), field); \ &v->field != (head); \ v = t, t = dm_list_struct_base(v->field.n, typeof(*v), field)) /* * Walk a list, setting 'v' in turn to the containing structure of each item. * The containing structure should be the same type as 'v'. * The list should be 'struct dm_list list' within the containing structure. * t must be defined as a temporary variable of the same type as v. */ #define dm_list_iterate_items_safe(v, t, head) \ dm_list_iterate_items_gen_safe(v, t, (head), list) /* * Walk a list backwards, setting 'v' in turn to the containing structure * of each item. * The containing structure should be the same type as 'v'. * The 'struct dm_list' variable within the containing structure is 'field'. */ #define dm_list_iterate_back_items_gen(v, head, field) \ for (v = dm_list_struct_base((head)->p, typeof(*v), field); \ &v->field != (head); \ v = dm_list_struct_base(v->field.p, typeof(*v), field)) /* * Walk a list backwards, setting 'v' in turn to the containing structure * of each item. * The containing structure should be the same type as 'v'. * The list should be 'struct dm_list list' within the containing structure. */ #define dm_list_iterate_back_items(v, head) dm_list_iterate_back_items_gen(v, (head), list) /* * Return the number of elements in a list by walking it. */ unsigned int dm_list_size(const struct dm_list *head); #endif