xref: /freebsd-11-stable/sys/dev/vxge/include/vxge-list.h

/*-
 * Copyright(c) 2002-2011 Exar Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification are permitted provided the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 *    3. Neither the name of the Exar Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
/*$FreeBSD$*/

#ifndef	VXGE_LIST_H
#define	VXGE_LIST_H

__EXTERN_BEGIN_DECLS

/*
 * struct vxge_list_t - List item.
 * @prev: Previous list item.
 * @next: Next list item.
 *
 * Item of a bi-directional linked list.
 */
typedef struct vxge_list_t {
	struct vxge_list_t		 *prev;
	struct vxge_list_t		 *next;
} vxge_list_t;

/*
 * vxge_list_init - Initialize linked list.
 * @header: first element of the list (head)
 *
 * Initialize linked list.
 * See also: vxge_list_t {}.
 */
static inline void vxge_list_init(vxge_list_t *header)
{
	vxge_assert(header != NULL);

	header->next = header;
	header->prev = header;
}

/*
 * vxge_list_is_empty - Is the list empty?
 * @header: first element of the list (head)
 *
 * Determine whether the bi-directional list is empty. Return '1' in
 * case of 'empty'.
 * See also: vxge_list_t {}.
 */
static inline int vxge_list_is_empty(vxge_list_t *header)
{
	vxge_assert(header != NULL);

	return (header->next == header);
}

/*
 * vxge_list_first_get - Return the first item from the linked list.
 * @header: first element of the list (head)
 *
 * Returns the next item from the header.
 * Returns NULL if the next item is header itself
 * See also: vxge_list_remove(), vxge_list_insert(), vxge_list_t {}.
 */
static inline vxge_list_t *vxge_list_first_get(vxge_list_t *header)
{
	vxge_assert(header != NULL);
	vxge_assert(header->next != NULL);
	vxge_assert(header->prev != NULL);

	if (header->next == header)
		return (NULL);
	else
		return (header->next);
}

/*
 * vxge_list_remove - Remove the specified item from the linked list.
 * @item: element of the list
 *
 * Remove item from a list.
 * See also: vxge_list_insert(), vxge_list_t {}.
 */
static inline void vxge_list_remove(vxge_list_t *item)
{
	vxge_assert(item != NULL);
	vxge_assert(item->next != NULL);
	vxge_assert(item->prev != NULL);

	item->next->prev = item->prev;
	item->prev->next = item->next;
#if defined(VXGE_DEBUG_ASSERT)
	item->next = item->prev = NULL;
#endif
}

/*
 * vxge_list_insert - Insert a new item after the specified item.
 * @new_item: new element of the list
 * @prev_item: element of the list after which the new element is
 *		inserted
 *
 * Insert new item (new_item) after given item (prev_item).
 * See also: vxge_list_remove(), vxge_list_insert_before(), vxge_list_t {}.
 */
static inline void vxge_list_insert(vxge_list_t *new_item,
    vxge_list_t *prev_item)
{
	vxge_assert(new_item != NULL);
	vxge_assert(prev_item != NULL);
	vxge_assert(prev_item->next != NULL);

	new_item->next = prev_item->next;
	new_item->prev = prev_item;
	prev_item->next->prev = new_item;
	prev_item->next = new_item;
}

/*
 * vxge_list_insert_before - Insert a new item before the specified item.
 * @new_item: new element of the list
 * @next_item: element of the list after which the new element is inserted
 *
 * Insert new item (new_item) before given item (next_item).
 */
static inline void vxge_list_insert_before(vxge_list_t *new_item,
    vxge_list_t * next_item)
{
	vxge_assert(new_item != NULL);
	vxge_assert(next_item != NULL);
	vxge_assert(next_item->next != NULL);

	new_item->next = next_item;
	new_item->prev = next_item->prev;
	next_item->prev->next = new_item;
	next_item->prev = new_item;
}

#define	vxge_list_for_each(_p, _h) \
	for (_p = (_h)->next, vxge_os_prefetch(_p->next); _p != (_h); \
		_p = _p->next, vxge_os_prefetch(_p->next))

#define	vxge_list_for_each_safe(_p, _n, _h) \
	for (_p = (_h)->next, _n = _p->next; _p != (_h); \
		_p = _n, _n = _p->next)

#define	vxge_list_for_each_prev_safe(_p, _n, _h) \
	for (_p = (_h)->prev, _n = _p->prev; _p != (_h); \
		_p = _n, _n = _p->prev)

#if defined(__GNUC__)
/*
 * vxge_container_of - Given a member, return 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.
 *
 * Cast a member of a structure out to the containing structure.
 */
#define	vxge_container_of(ptr, type, member) (\
	{ __typeof(((type *)0)->member) *__mptr = (ptr);	\
	(type *)(void *)((char *)__mptr - ((ptr_t)&((type *)0)->member)); })
#else
/* type unsafe version */
#define	vxge_container_of(ptr, type, member) \
	((type *)(void *)((char *)(ptr) - ((ptr_t)&((type *)0)->member)))
#endif

/*
 * vxge_offsetof - Offset of the member in the containing structure.
 * @t:	struct name.
 * @m:	the name of the member within the struct.
 *
 * Return the offset of the member @m in the structure @t.
 */
#define	vxge_offsetof(t, m)			((ptr_t)(&((t *)0)->m))

__EXTERN_END_DECLS

#endif	/* VXGE_LIST_H */