/*************************************************************************/ /*!
@File
@Title          Double linked list header
@Copyright      Copyright (c) Imagination Technologies Ltd. All Rights Reserved
@Description    Double linked list interface
@License        MIT

The contents of this file are subject to the MIT license as set out below.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

This License is also included in this distribution in the file called
"MIT-COPYING".

EXCEPT AS OTHERWISE STATED IN A NEGOTIATED AGREEMENT: (A) THE SOFTWARE IS
PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND NONINFRINGEMENT; AND (B) IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/ /**************************************************************************/

#ifndef _DLLIST_
#define _DLLIST_

#include "img_types.h"

/*!
	Pointer to a linked list node
*/
typedef struct _DLLIST_NODE_	*PDLLIST_NODE;


/*!
	Node in a linked list
*/
/*
 * Note: the following structure's size is architecture-dependent and
 * clients may need to create a mirror the structure definition if it needs
 * to be used in a structure shared between host and device. Consider such
 * clients if any changes are made to this structure.
 */ 
typedef struct _DLLIST_NODE_
{
	struct _DLLIST_NODE_	*psPrevNode;
	struct _DLLIST_NODE_	*psNextNode;
} DLLIST_NODE;


/*!
	Static initialiser
*/
#define DECLARE_DLLIST(n) \
DLLIST_NODE n = {&n, &n}


/*************************************************************************/ /*!
@Function       dllist_init

@Description    Initialize a new double linked list

@Input          psListHead              List head Node

*/
/*****************************************************************************/
static INLINE
void dllist_init(PDLLIST_NODE psListHead)
{
	psListHead->psPrevNode = psListHead;
	psListHead->psNextNode = psListHead;
}

/*************************************************************************/ /*!
@Function       dllist_is_empty

@Description    Returns whether the list is empty

@Input          psListHead              List head Node

*/
/*****************************************************************************/
static INLINE
IMG_BOOL dllist_is_empty(PDLLIST_NODE psListHead)
{
	return (IMG_BOOL) ((psListHead->psPrevNode == psListHead)
	                   && (psListHead->psNextNode == psListHead));
}

/*************************************************************************/ /*!
@Function       dllist_add_to_head

@Description    Add psNewNode to head of list psListHead

@Input          psListHead             Head Node
@Input          psNewNode              New Node

*/
/*****************************************************************************/
static INLINE
void dllist_add_to_head(PDLLIST_NODE psListHead, PDLLIST_NODE psNewNode)
{
	PDLLIST_NODE psTmp;

	psTmp = psListHead->psNextNode;

	psListHead->psNextNode = psNewNode;
	psNewNode->psNextNode = psTmp;

	psTmp->psPrevNode = psNewNode;
	psNewNode->psPrevNode = psListHead;
}


/*************************************************************************/ /*!
@Function       dllist_add_to_tail

@Description    Add psNewNode to tail of list psListHead

@Input          psListHead             Head Node
@Input          psNewNode              New Node

*/
/*****************************************************************************/
static INLINE
void dllist_add_to_tail(PDLLIST_NODE psListHead, PDLLIST_NODE psNewNode)
{
	PDLLIST_NODE psTmp;

	psTmp = psListHead->psPrevNode;

	psListHead->psPrevNode = psNewNode;
	psNewNode->psPrevNode = psTmp;

	psTmp->psNextNode = psNewNode;
	psNewNode->psNextNode = psListHead;
}

/*************************************************************************/ /*!
@Function       dllist_node_is_in_list

@Description    Returns IMG_TRUE if psNode is in a list 

@Input          psNode             List node

*/
/*****************************************************************************/
static INLINE
IMG_BOOL dllist_node_is_in_list(PDLLIST_NODE psNode)
{
	return (IMG_BOOL) (psNode->psNextNode != NULL);
}

/*************************************************************************/ /*!
@Function       dllist_get_next_node

@Description    Returns the list node after psListHead or NULL psListHead
				is the only element in the list.

@Input          psListHead             List node to start the operation

*/
/*****************************************************************************/
static INLINE
PDLLIST_NODE dllist_get_next_node(PDLLIST_NODE psListHead)
{
	if (psListHead->psNextNode == psListHead)
	{
		return NULL;
	}
	else
	{
		return psListHead->psNextNode;
	}
} 


/*************************************************************************/ /*!
@Function       dllist_remove_node

@Description    Removes psListNode from the list where it currently belongs

@Input          psListNode             List node to be removed

*/
/*****************************************************************************/
static INLINE
void dllist_remove_node(PDLLIST_NODE psListNode)
{
	psListNode->psNextNode->psPrevNode = psListNode->psPrevNode;
	psListNode->psPrevNode->psNextNode = psListNode->psNextNode;

	/* Clear the node to show it's not on a list */
	psListNode->psPrevNode = NULL;
	psListNode->psNextNode = NULL;
}

/*************************************************************************/ /*!
@Function       dllist_replace_head

@Description    Moves the list from psOldHead to psNewHead

@Input          psOldHead       List node to be replaced. Will become a head
                                node of an empty list.
@Input          psNewHead       List node to be inserted. Must be an empty list
                                head.

*/
/*****************************************************************************/
static INLINE
void dllist_replace_head(PDLLIST_NODE psOldHead, PDLLIST_NODE psNewHead)
{
	if (dllist_is_empty(psOldHead))
	{
		psNewHead->psNextNode = psNewHead;
		psNewHead->psPrevNode = psNewHead;
	}
	else
	{
		/* Change the neighbouring nodes */
		psOldHead->psNextNode->psPrevNode = psNewHead;
		psOldHead->psPrevNode->psNextNode = psNewHead;

		/* Copy the old data to the new node */
		psNewHead->psNextNode = psOldHead->psNextNode;
		psNewHead->psPrevNode = psOldHead->psPrevNode;

		/* Remove links to the previous list */
		psOldHead->psNextNode = psOldHead;
		psOldHead->psPrevNode = psOldHead;
	}


}

/*************************************************************************/ /*!
@Function       dllist_foreach_node

@Description    Walk through all the nodes on the list.
				Safe against removal of (node).

@Input          list_head			List node to start the operation
@Input			node				Current list node
@Input			next				Node after the current one

*/
/*****************************************************************************/
#define dllist_foreach_node(list_head, node, next)						\
	for (node = (list_head)->psNextNode, next = (node)->psNextNode;		\
		 node != (list_head);											\
		 node = next, next = (node)->psNextNode)

#define dllist_foreach_node_backwards(list_head, node, prev)			\
	for (node = (list_head)->psPrevNode, prev = (node)->psPrevNode;		\
		 node != (list_head);											\
		 node = prev, prev = (node)->psPrevNode)

#endif	/* _DLLIST_ */