/*
 * Copyright 2012 Samy Al Bahra.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that 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.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *	@(#)queue.h	8.5 (Berkeley) 8/20/94
 * $FreeBSD: release/9.0.0/sys/sys/queue.h 221843 2011-05-13 15:49:23Z mdf $
 */

#ifndef _CK_QUEUE_H_
#define	_CK_QUEUE_H_

#include <ck_pr.h>

/*
 * This file defines four types of data structures: singly-linked lists,
 * singly-linked tail queues, lists and tail queues.
 *
 * A singly-linked list is headed by a single forward pointer. The elements
 * are singly linked for minimum space and pointer manipulation overhead at
 * the expense of O(n) removal for arbitrary elements. New elements can be
 * added to the list after an existing element or at the head of the list.
 * Elements being removed from the head of the list should use the explicit
 * macro for this purpose for optimum efficiency. A singly-linked list may
 * only be traversed in the forward direction.  Singly-linked lists are ideal
 * for applications with large datasets and few or no removals or for
 * implementing a LIFO queue.
 *
 * A list is headed by a single forward pointer (or an array of forward
 * pointers for a hash table header). The elements are doubly linked
 * so that an arbitrary element can be removed without a need to
 * traverse the list. New elements can be added to the list before
 * or after an existing element or at the head of the list. A list
 * may only be traversed in the forward direction.
 *
 * It is safe to use _FOREACH/_FOREACH_SAFE in the presence of concurrent
 * modifications to the list. Writers to these lists must, on the other hand,
 * implement writer-side synchronization. The _SWAP operations are not atomic.
 * This facility is currently unsupported on architectures such as the Alpha
 * which require load-depend memory fences.
 *
 *				CK_SLIST	CK_LIST
 * _HEAD			+		+
 * _HEAD_INITIALIZER		+		+
 * _ENTRY			+		+
 * _INIT			+		+
 * _EMPTY			+		+
 * _FIRST			+		+
 * _NEXT			+		+
 * _FOREACH			+		+
 * _FOREACH_SAFE		+		+
 * _INSERT_HEAD			+		+
 * _INSERT_BEFORE		-		+
 * _INSERT_AFTER		+		+
 * _REMOVE_AFTER		+		-
 * _REMOVE_HEAD			+		-
 * _REMOVE			+		+
 * _SWAP			+		+
 */

/*
 * Singly-linked List declarations.
 */
#define	CK_SLIST_HEAD(name, type)						\
struct name {									\
	struct type *slh_first;	/* first element */				\
}

#define	CK_SLIST_HEAD_INITIALIZER(head)						\
	{ NULL }

#define	CK_SLIST_ENTRY(type)							\
struct {									\
	struct type *sle_next;	/* next element */				\
}

/*
 * Singly-linked List functions.
 */
#define	CK_SLIST_EMPTY(head)							\
	(ck_pr_load_ptr(&(head)->slh_first) == NULL)

#define	CK_SLIST_FIRST(head)							\
	(ck_pr_load_ptr(&(head)->slh_first))

#define	CK_SLIST_NEXT(elm, field)						\
	ck_pr_load_ptr(&((elm)->field.sle_next))

#define	CK_SLIST_FOREACH(var, head, field)					\
	for ((var) = CK_SLIST_FIRST((head));					\
	    (var) && (ck_pr_fence_load(), 1);					\
	    (var) = CK_SLIST_NEXT((var), field))

#define	CK_SLIST_FOREACH_SAFE(var, head, field, tvar)				 \
	for ((var) = CK_SLIST_FIRST(head);					 \
	    (var) && (ck_pr_fence_load(), (tvar) = CK_SLIST_NEXT(var, field), 1);\
	    (var) = (tvar))

#define	CK_SLIST_FOREACH_PREVPTR(var, varp, head, field)			\
	for ((varp) = &(head)->slh_first;					\
	    ((var) = ck_pr_load_ptr(varp)) != NULL && (ck_pr_fence_load(), 1);	\
	    (varp) = &(var)->field.sle_next)

#define	CK_SLIST_INIT(head) do {						\
	ck_pr_store_ptr(&(head)->slh_first, NULL);				\
	ck_pr_fence_store();							\
} while (0)

#define	CK_SLIST_INSERT_AFTER(a, b, field) do {					\
	(b)->field.sle_next = (a)->field.sle_next;				\
	ck_pr_fence_store();							\
	ck_pr_store_ptr(&(a)->field.sle_next, b);				\
} while (0)

#define	CK_SLIST_INSERT_HEAD(head, elm, field) do {				\
	(elm)->field.sle_next = (head)->slh_first;				\
	ck_pr_fence_store();							\
	ck_pr_store_ptr(&(head)->slh_first, elm);				\
} while (0)

#define CK_SLIST_REMOVE_AFTER(elm, field) do {					\
	ck_pr_store_ptr(&(elm)->field.sle_next,					\
	    (elm)->field.sle_next->field.sle_next);				\
} while (0)

#define	CK_SLIST_REMOVE(head, elm, type, field) do {				\
	if ((head)->slh_first == (elm)) {					\
		CK_SLIST_REMOVE_HEAD((head), field);				\
	} else {								\
		struct type *curelm = (head)->slh_first;			\
		while (curelm->field.sle_next != (elm))				\
			curelm = curelm->field.sle_next;			\
		CK_SLIST_REMOVE_AFTER(curelm, field);				\
	}									\
} while (0)

#define	CK_SLIST_REMOVE_HEAD(head, field) do {					\
	ck_pr_store_ptr(&(head)->slh_first,					\
		(head)->slh_first->field.sle_next);				\
} while (0)

/*
 * This operation is not applied atomically.
 */
#define CK_SLIST_SWAP(a, b, type) do {						\
	struct type *swap_first = (a)->slh_first;				\
	(a)->slh_first = (b)->slh_first;					\
	(b)->slh_first = swap_first;						\
} while (0)

/*
 * List declarations.
 */
#define	CK_LIST_HEAD(name, type)						\
struct name {									\
	struct type *lh_first;	/* first element */				\
}

#define	CK_LIST_HEAD_INITIALIZER(head)						\
	{ NULL }

#define	CK_LIST_ENTRY(type)							\
struct {									\
	struct type *le_next;	/* next element */				\
	struct type **le_prev;	/* address of previous next element */		\
}

#define	CK_LIST_FIRST(head)		ck_pr_load_ptr(&(head)->lh_first)
#define	CK_LIST_EMPTY(head)		(CK_LIST_FIRST(head) == NULL)
#define	CK_LIST_NEXT(elm, field)	ck_pr_load_ptr(&(elm)->field.le_next)

#define	CK_LIST_FOREACH(var, head, field)					\
	for ((var) = CK_LIST_FIRST((head));					\
	    (var) && (ck_pr_fence_load(), 1);					\
	    (var) = CK_LIST_NEXT((var), field))

#define	CK_LIST_FOREACH_SAFE(var, head, field, tvar)				  \
	for ((var) = CK_LIST_FIRST((head));					  \
	    (var) && (ck_pr_fence_load(), (tvar) = CK_LIST_NEXT((var), field), 1);\
	    (var) = (tvar))

#define	CK_LIST_INIT(head) do {							\
	ck_pr_store_ptr(&(head)->lh_first, NULL);				\
	ck_pr_fence_store();							\
} while (0)

#define	CK_LIST_INSERT_AFTER(listelm, elm, field) do {				\
	(elm)->field.le_next = (listelm)->field.le_next;			\
	(elm)->field.le_prev = &(listelm)->field.le_next;			\
	ck_pr_fence_store();							\
	if ((listelm)->field.le_next != NULL)					\
		(listelm)->field.le_next->field.le_prev = &(elm)->field.le_next;\
	ck_pr_store_ptr(&(listelm)->field.le_next, elm);			\
} while (0)

#define	CK_LIST_INSERT_BEFORE(listelm, elm, field) do {				\
	(elm)->field.le_prev = (listelm)->field.le_prev;			\
	(elm)->field.le_next = (listelm);					\
	ck_pr_fence_store();							\
	ck_pr_store_ptr((listelm)->field.le_prev, (elm));			\
	(listelm)->field.le_prev = &(elm)->field.le_next;			\
} while (0)

#define	CK_LIST_INSERT_HEAD(head, elm, field) do {				\
	(elm)->field.le_next = (head)->lh_first;				\
	ck_pr_fence_store();							\
	ck_pr_store_ptr(&(head)->lh_first, elm);				\
	if ((elm)->field.le_next != NULL)					\
		(head)->lh_first->field.le_prev =  &(elm)->field.le_next;	\
	(elm)->field.le_prev = &(head)->lh_first;				\
} while (0)

#define	CK_LIST_REMOVE(elm, field) do {						\
	ck_pr_store_ptr((elm)->field.le_prev, (elm)->field.le_next);		\
	if ((elm)->field.le_next != NULL)					\
		(elm)->field.le_next->field.le_prev = (elm)->field.le_prev;	\
} while (0)

/*
 * This operation is not applied atomically.
 */
#define CK_LIST_SWAP(head1, head2, type, field) do {			\
	struct type *swap_tmp = (head1)->lh_first;			\
	(head1)->lh_first = (head2)->lh_first;				\
	(head2)->lh_first = swap_tmp;					\
	if ((swap_tmp = (head1)->lh_first) != NULL)			\
		swap_tmp->field.le_prev = &(head1)->lh_first;		\
	if ((swap_tmp = (head2)->lh_first) != NULL)			\
		swap_tmp->field.le_prev = &(head2)->lh_first;		\
} while (0)

#endif /* _CK_QUEUE_H */