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| Current File : //sys/dev/isci/scil/sci_fast_list.h |
/*-
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
* The full GNU General Public License is included in this distribution
* in the file called LICENSE.GPL.
*
* BSD LICENSE
*
* Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 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: release/9.1.0/sys/dev/isci/scil/sci_fast_list.h 231689 2012-02-14 15:58:49Z jimharris $
*/
#ifndef _SCI_FAST_LIST_HEADER_
#define _SCI_FAST_LIST_HEADER_
/**
* @file
*
* @brief Header file that contains basic Linked List manipulation macros.
* These macros implement a double linked list (SCI_FAST_LIST_T) that is
* circular in nature. This means that the next and prev pointers for
* an empty queue head always the address of the queue head
* SCI_FAST_LIST_T. Likewise an element that has been removed from
* a queue will have its next and prev pointer set to the address of
* the SCI_FAST_LIST_T found in the structure just removed from the
* queue. Pointers in this implementation never == NULL.
*
* Definitions:
* - anchor : This is ths list container and has a
* pointer to both the head and tail of the
* list elements
* - element: This is the list element not the actual
* object but the list element which has a
* pointer to the object.
*/
//******************************************************************************
//*
//* P U B L I C M E T H O D S
//*
//******************************************************************************
/**
* Initialize the double linked list anchor. The other macros require the list
* anchor to be set up using this macro.
*/
#define sci_fast_list_init(anchor) \
{ \
(anchor)->list_head = NULL; \
(anchor)->list_tail = NULL; \
(anchor)->element_count = 0; \
}
/**
* Initialize the sci_fast_list_element to point to its owning object
*/
#define sci_fast_list_element_init(list_object, element) \
{ \
(element)->object = (list_object); \
(element)->next = (element)->prev = NULL; \
(element)->owning_list = NULL; \
}
/**
* See if there is anything on the list by checking the list anchor.
*/
#define sci_fast_list_is_empty(anchor) ((anchor)->list_head == NULL)
/**
* Return a pointer to the element at the head of the sci_fast_list. The
* item is NOT removed from the list.
*
* NOTE: This macro will always return a value, even if the list is empty.
* You must insure the list is not empty or use Dlist_safeGetHead.
*
* element - A pointer into which to save the address of the structure
* containing the SCI_FAST_LIST at the list head.
*/
#define sci_fast_list_get_head(anchor) \
((anchor)->list_head == NULL ? NULL: (anchor)->list_head->object)
/**
* Return a pointer to the element at the tail of the sci_fast_list. The item
* is NOT removed from the list.
*
* NOTE: This macro will always return a value, even if the list is empty.
* You must insure the list is not empty or use Dlist_safeGetHead.
*
* element - A pointer into which to save the address of the structure
* containing the SCI_FAST_LIST at the list head.
*/
#define sci_fast_list_get_tail(anchor) \
((anchor)->list_tail == NULL ? NULL: (anchor)->list_head->object)
/**
* This method will get the next dListField in the SCI_FAST_LIST. This method
* returns a pointer to a SCI_FAST_LIST object.
*/
#define sci_fast_list_get_next(element) ((element)->next)
/**
* This method will get the prev dListField in the SCI_FAST_LIST. This method
* returns a pointer to a SCI_FAST_LIST object.
*/
#define sci_fast_list_get_prev(element) ((element)->prev)
/**
* This method returns the object that is represented by this
* sci_fast_list_element
*/
#define sci_fast_list_get_object(element) ((element)->object)
/**
* This method will determine if the supplied dListField is on a SCI_FAST_LIST.
* If the element has only one dListField but can be on more than one list,
* this will only tell you that it is on one of them. If the element has
* multiple dListFields and can exist on multiple lists at the same time, this
* macro can tell you exactly which list it is on.
*/
#define sci_fast_list_is_on_a_list(element) ((element)->owning_list != NULL)
/**
* This method will determine if the supplied dListFieldName is on the given
* specified list? If the element can be on more than one list, this
* allows you to determine exactly which list it is on. Performs a linear
* search through the list.
* result - BOOL_T that will contain the result of the search.
* TRUE - item is on the list described by head.
* FALSE - item is not on the list.
*/
#define sci_fast_list_is_on_this_list(anchor, element) \
((element)->owning_list == (anchor))
//******************************************************************************
//*
//* T Y P E S
//*
//******************************************************************************
/**
* @struct SCI_FAST_LIST
*
* @brief the list owner or list anchor for a set of SCI_FAST_LIST
* elements.
*/
typedef struct SCI_FAST_LIST
{
struct SCI_FAST_LIST_ELEMENT *list_head;
struct SCI_FAST_LIST_ELEMENT *list_tail;
int element_count;
} SCI_FAST_LIST_T;
/**
* @struct SCI_FAST_LIST_ELEMENT
*
* @brief This structure defines what a doubly linked list element contains.
*/
typedef struct SCI_FAST_LIST_ELEMENT
{
struct SCI_FAST_LIST_ELEMENT *next;
struct SCI_FAST_LIST_ELEMENT *prev;
struct SCI_FAST_LIST *owning_list;
void *object;
} SCI_FAST_LIST_ELEMENT_T;
/**
* Insert an element to be the new head of the list hanging off of the list
* anchor. An empty list has the list anchor pointing to itself.
* dListAnchor - The name of the SCI_FAST_LIST_T element that is the anchor
* of the queue.
* dListFieldBeingInserted - The SCI_FAST_LIST_T field in the data structure
* being queued. This SCI_FAST_LIST will become
* the new list head.
*/
INLINE
static void sci_fast_list_insert_head(
SCI_FAST_LIST_T *anchor,
SCI_FAST_LIST_ELEMENT_T *element
)
{
element->owning_list = anchor;
element->prev = NULL;
if ( anchor->list_head == NULL )
anchor->list_tail = element;
else
anchor->list_head->prev = element;
element->next = anchor->list_head;
anchor->list_head = element;
anchor->element_count++;
}
/**
* Insert an element at the tail of the list. Since the list is circular we
* can add the element at the tail through use the list anchors previous
* pointer.
* dListAnchor - The name of the SCI_FAST_LIST_T element that is the anchor
* of the queue.
* dListFieldBeingInserted - The SCI_FAST_LIST_T field in the data structure
* being queued. This SCI_FAST_LIST will become
* the new list head.
*/
INLINE
static void sci_fast_list_insert_tail(
SCI_FAST_LIST_T *anchor,
SCI_FAST_LIST_ELEMENT_T *element
)
{
element->owning_list = anchor;
element->next = NULL;
if ( anchor->list_tail == NULL ) {
anchor->list_head = element;
} else {
anchor->list_tail->next = element;
}
element->prev = anchor->list_tail;
anchor->list_tail = element;
anchor->element_count++;
}
/**
* This method will remove a dListFieldName from the head of the list.
*
* NOTE: This macro will always return a value, even if the list is empty.
* You must insure the list is not empty or use Dlist_safeRemoveHead.
*
* element - A pointer into which to save the address of the structure
* containing the SCI_FAST_LIST at the list head.
*/
INLINE
static void *sci_fast_list_remove_head(
SCI_FAST_LIST_T *anchor
)
{
void *object = NULL;
SCI_FAST_LIST_ELEMENT_T *element;
if ( anchor->list_head != NULL )
{
element = anchor->list_head;
object = anchor->list_head->object;
anchor->list_head = anchor->list_head->next;
if ( anchor->list_head == NULL )
{
anchor->list_tail = NULL;
}
anchor->element_count--;
element->next = element->prev = NULL;
element->owning_list = NULL;
}
return object;
}
INLINE
static void *sci_fast_list_remove_tail(
SCI_FAST_LIST_T *anchor
)
{
void *object = NULL;
SCI_FAST_LIST_ELEMENT_T *element;
if ( anchor->list_tail != NULL )
{
element = anchor->list_tail;
object = element->object;
anchor->list_tail = element->prev;
if ( anchor->list_tail == NULL )
anchor->list_head = NULL;
anchor->element_count--;
element->next = element->prev = NULL;
element->owning_list = NULL;
}
return object;
}
/**
* Remove an element from anywhere in the list referenced by name.
*/
INLINE
static void sci_fast_list_remove_element(
SCI_FAST_LIST_ELEMENT_T *element
)
{
if ( element->next == NULL )
element->owning_list->list_tail = element->prev;
else
element->next->prev = element->prev;
if ( element->prev == NULL )
element->owning_list->list_head = element->next;
else
element->prev->next = element->next;
element->owning_list->element_count--;
element->next = element->prev = NULL;
element->owning_list = NULL;
}
#endif // _SCI_FAST_LIST_HEADER_