Source/list.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
     FreeRTOS V6.1.0 - Copyright (C) 2010 Real Time Engineers Ltd.

     ***************************************************************************
     *                                                                         *
     * If you are:                                                             *
     *                                                                         *
     *    + New to FreeRTOS,                                                   *
     *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
     *    + Looking for basic training,                                        *
     *    + Wanting to improve your FreeRTOS skills and productivity           *
     *                                                                         *
     * then take a look at the FreeRTOS books - available as PDF or paperback  *
     *                                                                         *
     *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
     *                  http://www.FreeRTOS.org/Documentation                  *
     *                                                                         *
     * A pdf reference manual is also available.  Both are usually delivered   *
     * to your inbox within 20 minutes to two hours when purchased between 8am *
     * and 8pm GMT (although please allow up to 24 hours in case of            *
     * exceptional circumstances).  Thank you for your support!                *
     *                                                                         *
     ***************************************************************************

     This file is part of the FreeRTOS distribution.

     FreeRTOS is free software; you can redistribute it and/or modify it under
     the terms of the GNU General Public License (version 2) as published by the
     Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
     ***NOTE*** The exception to the GPL is included to allow you to distribute
     a combined work that includes FreeRTOS without being obliged to provide the
     source code for proprietary components outside of the FreeRTOS kernel.
     FreeRTOS 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 and the FreeRTOS license exception along with FreeRTOS; if not it
     can be viewed here: http://www.freertos.org/a00114.html and also obtained
     by writing to Richard Barry, contact details for whom are available on the
     FreeRTOS WEB site.

     1 tab == 4 spaces!

     http://www.FreeRTOS.org - Documentation, latest information, license and
     contact details.

     http://www.SafeRTOS.com - A version that is certified for use in safety
     critical systems.

     http://www.OpenRTOS.com - Commercial support, development, porting,
     licensing and training services.
 */


 #include <stdlib.h>
 #include "FreeRTOS.h"
 #include "list.h"

 /*-----------------------------------------------------------
  * PUBLIC LIST API documented in list.h
  *----------------------------------------------------------*/

 void vListInitialise( xList *pxList )
 {
 	/* The list structure contains a list item which is used to mark the
 	end of the list.  To initialise the list the list end is inserted
 	as the only list entry. */
 	pxList->pxIndex = ( xListItem * ) &( pxList->xListEnd );

 	/* The list end value is the highest possible value in the list to
 	ensure it remains at the end of the list. */
 	pxList->xListEnd.xItemValue = portMAX_DELAY;

 	/* The list end next and previous pointers point to itself so we know
 	when the list is empty. */
 	pxList->xListEnd.pxNext = ( xListItem * ) &( pxList->xListEnd );
 	pxList->xListEnd.pxPrevious = ( xListItem * ) &( pxList->xListEnd );

 	pxList->uxNumberOfItems = 0;
 }
 /*-----------------------------------------------------------*/

 void vListInitialiseItem( xListItem *pxItem )
 {
 	/* Make sure the list item is not recorded as being on a list. */
 	pxItem->pvContainer = NULL;
 }
 /*-----------------------------------------------------------*/

 void vListInsertEnd( xList *pxList, xListItem *pxNewListItem )
 {
 volatile xListItem * pxIndex;

 	/* Insert a new list item into pxList, but rather than sort the list,
 	makes the new list item the last item to be removed by a call to
 	pvListGetOwnerOfNextEntry.  This means it has to be the item pointed to by
 	the pxIndex member. */
 	pxIndex = pxList->pxIndex;

 	pxNewListItem->pxNext = pxIndex->pxNext;
 	pxNewListItem->pxPrevious = pxList->pxIndex;
 	pxIndex->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
 	pxIndex->pxNext = ( volatile xListItem * ) pxNewListItem;
 	pxList->pxIndex = ( volatile xListItem * ) pxNewListItem;

 	/* Remember which list the item is in. */
 	pxNewListItem->pvContainer = ( void * ) pxList;

 	( pxList->uxNumberOfItems )++;
 }
 /*-----------------------------------------------------------*/

 void vListInsert( xList *pxList, xListItem *pxNewListItem )
 {
 volatile xListItem *pxIterator;
 portTickType xValueOfInsertion;

 	/* Insert the new list item into the list, sorted in ulListItem order. */
 	xValueOfInsertion = pxNewListItem->xItemValue;

 	/* If the list already contains a list item with the same item value then
 	the new list item should be placed after it.  This ensures that TCB's which
 	are stored in ready lists (all of which have the same ulListItem value)
 	get an equal share of the CPU.  However, if the xItemValue is the same as
 	the back marker the iteration loop below will not end.  This means we need
 	to guard against this by checking the value first and modifying the
 	algorithm slightly if necessary. */
 	if( xValueOfInsertion == portMAX_DELAY )
 	{
 		pxIterator = pxList->xListEnd.pxPrevious;
 	}
 	else
 	{
 		/* *** NOTE ***********************************************************
 		If you find your application is crashing here then likely causes are:
 			1) Stack overflow -
 			   see http://www.freertos.org/Stacks-and-stack-overflow-checking.html
 			2) Incorrect interrupt priority assignment, especially on Cortex M3
 			   parts where numerically high priority values denote low actual
 			   interrupt priories, which can seem counter intuitive.  See
 			   configMAX_SYSCALL_INTERRUPT_PRIORITY on http://www.freertos.org/a00110.html
 			3) Calling an API function from within a critical section or when
 			   the scheduler is suspended.
 			4) Using a queue or semaphore before it has been initialised or
 			   before the scheduler has been started (are interrupts firing
 			   before vTaskStartScheduler() has been called?).
 		See http://www.freertos.org/FAQHelp.html for more tips.
 		**********************************************************************/

 		for( pxIterator = ( xListItem * ) &( pxList->xListEnd ); pxIterator->pxNext->xItemValue <= xValueOfInsertion; pxIterator = pxIterator->pxNext )
 		{
 			/* There is nothing to do here, we are just iterating to the
 			wanted insertion position. */
 		}
 	}

 	pxNewListItem->pxNext = pxIterator->pxNext;
 	pxNewListItem->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
 	pxNewListItem->pxPrevious = pxIterator;
 	pxIterator->pxNext = ( volatile xListItem * ) pxNewListItem;

 	/* Remember which list the item is in.  This allows fast removal of the
 	item later. */
 	pxNewListItem->pvContainer = ( void * ) pxList;

 	( pxList->uxNumberOfItems )++;
 }
 /*-----------------------------------------------------------*/

 void vListRemove( xListItem *pxItemToRemove )
 {
 xList * pxList;

 	pxItemToRemove->pxNext->pxPrevious = pxItemToRemove->pxPrevious;
 	pxItemToRemove->pxPrevious->pxNext = pxItemToRemove->pxNext;

 	/* The list item knows which list it is in.  Obtain the list from the list
 	item. */
 	pxList = ( xList * ) pxItemToRemove->pvContainer;

 	/* Make sure the index is left pointing to a valid item. */
 	if( pxList->pxIndex == pxItemToRemove )
 	{
 		pxList->pxIndex = pxItemToRemove->pxPrevious;
 	}

 	pxItemToRemove->pvContainer = NULL;
 	( pxList->uxNumberOfItems )--;
 }
 /*-----------------------------------------------------------*/
	/*
	FreeRTOS V6.1.0 - Copyright (C) 2010 Real Time Engineers Ltd.

	***************************************************************************
	* *
	* If you are: *
	* *
	* + New to FreeRTOS, *
	* + Wanting to learn FreeRTOS or multitasking in general quickly *
	* + Looking for basic training, *
	* + Wanting to improve your FreeRTOS skills and productivity *
	* *
	* then take a look at the FreeRTOS books - available as PDF or paperback *
	* *
	* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
	* http://www.FreeRTOS.org/Documentation *
	* *
	* A pdf reference manual is also available. Both are usually delivered *
	* to your inbox within 20 minutes to two hours when purchased between 8am *
	* and 8pm GMT (although please allow up to 24 hours in case of *
	* exceptional circumstances). Thank you for your support! *
	* *
	***************************************************************************

	This file is part of the FreeRTOS distribution.

	FreeRTOS is free software; you can redistribute it and/or modify it under
	the terms of the GNU General Public License (version 2) as published by the
	Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
	*NOTE* The exception to the GPL is included to allow you to distribute
	a combined work that includes FreeRTOS without being obliged to provide the
	source code for proprietary components outside of the FreeRTOS kernel.
	FreeRTOS 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 and the FreeRTOS license exception along with FreeRTOS; if not it
	can be viewed here: http://www.freertos.org/a00114.html and also obtained
	by writing to Richard Barry, contact details for whom are available on the
	FreeRTOS WEB site.

	1 tab == 4 spaces!

	http://www.FreeRTOS.org - Documentation, latest information, license and
	contact details.

	http://www.SafeRTOS.com - A version that is certified for use in safety
	critical systems.

	http://www.OpenRTOS.com - Commercial support, development, porting,
	licensing and training services.
	*/


	#include <stdlib.h>
	#include "FreeRTOS.h"
	#include "list.h"

	/*-----------------------------------------------------------
	* PUBLIC LIST API documented in list.h
	----------------------------------------------------------/

	void vListInitialise( xList *pxList )
	{
	/* The list structure contains a list item which is used to mark the
	end of the list. To initialise the list the list end is inserted
	as the only list entry. */
	pxList->pxIndex = ( xListItem * ) &( pxList->xListEnd );

	/* The list end value is the highest possible value in the list to
	ensure it remains at the end of the list. */
	pxList->xListEnd.xItemValue = portMAX_DELAY;

	/* The list end next and previous pointers point to itself so we know
	when the list is empty. */
	pxList->xListEnd.pxNext = ( xListItem * ) &( pxList->xListEnd );
	pxList->xListEnd.pxPrevious = ( xListItem * ) &( pxList->xListEnd );

	pxList->uxNumberOfItems = 0;
	}
	/-----------------------------------------------------------/

	void vListInitialiseItem( xListItem *pxItem )
	{
	/* Make sure the list item is not recorded as being on a list. */
	pxItem->pvContainer = NULL;
	}
	/-----------------------------------------------------------/

	void vListInsertEnd( xList pxList, xListItem pxNewListItem )
	{
	volatile xListItem * pxIndex;

	/* Insert a new list item into pxList, but rather than sort the list,
	makes the new list item the last item to be removed by a call to
	pvListGetOwnerOfNextEntry. This means it has to be the item pointed to by
	the pxIndex member. */
	pxIndex = pxList->pxIndex;

	pxNewListItem->pxNext = pxIndex->pxNext;
	pxNewListItem->pxPrevious = pxList->pxIndex;
	pxIndex->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
	pxIndex->pxNext = ( volatile xListItem * ) pxNewListItem;
	pxList->pxIndex = ( volatile xListItem * ) pxNewListItem;

	/* Remember which list the item is in. */
	pxNewListItem->pvContainer = ( void * ) pxList;

	( pxList->uxNumberOfItems )++;
	}
	/-----------------------------------------------------------/

	void vListInsert( xList pxList, xListItem pxNewListItem )
	{
	volatile xListItem *pxIterator;
	portTickType xValueOfInsertion;

	/* Insert the new list item into the list, sorted in ulListItem order. */
	xValueOfInsertion = pxNewListItem->xItemValue;

	/* If the list already contains a list item with the same item value then
	the new list item should be placed after it. This ensures that TCB's which
	are stored in ready lists (all of which have the same ulListItem value)
	get an equal share of the CPU. However, if the xItemValue is the same as
	the back marker the iteration loop below will not end. This means we need
	to guard against this by checking the value first and modifying the
	algorithm slightly if necessary. */
	if( xValueOfInsertion == portMAX_DELAY )
	{
	pxIterator = pxList->xListEnd.pxPrevious;
	}
	else
	{
	/* * NOTE *********************************************************
	If you find your application is crashing here then likely causes are:
	1) Stack overflow -
	see http://www.freertos.org/Stacks-and-stack-overflow-checking.html
	2) Incorrect interrupt priority assignment, especially on Cortex M3
	parts where numerically high priority values denote low actual
	interrupt priories, which can seem counter intuitive. See
	configMAX_SYSCALL_INTERRUPT_PRIORITY on http://www.freertos.org/a00110.html
	3) Calling an API function from within a critical section or when
	the scheduler is suspended.
	4) Using a queue or semaphore before it has been initialised or
	before the scheduler has been started (are interrupts firing
	before vTaskStartScheduler() has been called?).
	See http://www.freertos.org/FAQHelp.html for more tips.
	**********************************************************************/

	for( pxIterator = ( xListItem * ) &( pxList->xListEnd ); pxIterator->pxNext->xItemValue <= xValueOfInsertion; pxIterator = pxIterator->pxNext )
	{
	/* There is nothing to do here, we are just iterating to the
	wanted insertion position. */
	}
	}

	pxNewListItem->pxNext = pxIterator->pxNext;
	pxNewListItem->pxNext->pxPrevious = ( volatile xListItem * ) pxNewListItem;
	pxNewListItem->pxPrevious = pxIterator;
	pxIterator->pxNext = ( volatile xListItem * ) pxNewListItem;

	/* Remember which list the item is in. This allows fast removal of the
	item later. */
	pxNewListItem->pvContainer = ( void * ) pxList;

	( pxList->uxNumberOfItems )++;
	}
	/-----------------------------------------------------------/

	void vListRemove( xListItem *pxItemToRemove )
	{
	xList * pxList;

	pxItemToRemove->pxNext->pxPrevious = pxItemToRemove->pxPrevious;
	pxItemToRemove->pxPrevious->pxNext = pxItemToRemove->pxNext;

	/* The list item knows which list it is in. Obtain the list from the list
	item. */
	pxList = ( xList * ) pxItemToRemove->pvContainer;

	/* Make sure the index is left pointing to a valid item. */
	if( pxList->pxIndex == pxItemToRemove )
	{
	pxList->pxIndex = pxItemToRemove->pxPrevious;
	}

	pxItemToRemove->pvContainer = NULL;
	( pxList->uxNumberOfItems )--;
	}
	/-----------------------------------------------------------/