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

 /*
     FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.

     FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT
     http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

     ***************************************************************************
      *                                                                       *
      *    FreeRTOS tutorial books are available in pdf and paperback.        *
      *    Complete, revised, and edited pdf reference manuals are also       *
      *    available.                                                         *
      *                                                                       *
      *    Purchasing FreeRTOS documentation will not only help you, by       *
      *    ensuring you get running as quickly as possible and with an        *
      *    in-depth knowledge of how to use FreeRTOS, it will also help       *
      *    the FreeRTOS project to continue with its mission of providing     *
      *    professional grade, cross platform, de facto standard solutions    *
      *    for microcontrollers - completely free of charge!                  *
      *                                                                       *
      *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
      *                                                                       *
      *    Thank you for using FreeRTOS, and 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 modification 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 Real Time Engineers Ltd., contact details for whom are available
     on the FreeRTOS WEB site.

     1 tab == 4 spaces!

     ***************************************************************************
      *                                                                       *
      *    Having a problem?  Start by reading the FAQ "My application does   *
      *    not run, what could be wrong?"                                     *
      *                                                                       *
      *    http://www.FreeRTOS.org/FAQHelp.html                               *
      *                                                                       *
     ***************************************************************************


     http://www.FreeRTOS.org - Documentation, books, training, latest versions,
     license and Real Time Engineers Ltd. contact details.

     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
     including FreeRTOS+Trace - an indispensable productivity tool, and our new
     fully thread aware and reentrant UDP/IP stack.

     http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
     Integrity Systems, who sell the code with commercial support,
     indemnification and middleware, under the OpenRTOS brand.

     http://www.SafeRTOS.com - High Integrity Systems also provide a safety
     engineered and independently SIL3 certified version for use in safety and
     mission critical applications that require provable dependability.
 */


 #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 = ( unsigned portBASE_TYPE ) 0U;
 }
 /*-----------------------------------------------------------*/

 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 )++;
 }
 /*-----------------------------------------------------------*/

 unsigned portBASE_TYPE uxListRemove( 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 )--;

 	return pxList->uxNumberOfItems;
 }
 /*-----------------------------------------------------------*/
	/*
	FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.

	FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
	http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

	***************************************************************************
	* *
	* FreeRTOS tutorial books are available in pdf and paperback. *
	* Complete, revised, and edited pdf reference manuals are also *
	* available. *
	* *
	* Purchasing FreeRTOS documentation will not only help you, by *
	* ensuring you get running as quickly as possible and with an *
	* in-depth knowledge of how to use FreeRTOS, it will also help *
	* the FreeRTOS project to continue with its mission of providing *
	* professional grade, cross platform, de facto standard solutions *
	* for microcontrollers - completely free of charge! *
	* *
	* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
	* *
	* Thank you for using FreeRTOS, and 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 modification 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 Real Time Engineers Ltd., contact details for whom are available
	on the FreeRTOS WEB site.

	1 tab == 4 spaces!

	***************************************************************************
	* *
	* Having a problem? Start by reading the FAQ "My application does *
	* not run, what could be wrong?" *
	* *
	* http://www.FreeRTOS.org/FAQHelp.html *
	* *
	***************************************************************************


	http://www.FreeRTOS.org - Documentation, books, training, latest versions,
	license and Real Time Engineers Ltd. contact details.

	http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
	including FreeRTOS+Trace - an indispensable productivity tool, and our new
	fully thread aware and reentrant UDP/IP stack.

	http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
	Integrity Systems, who sell the code with commercial support,
	indemnification and middleware, under the OpenRTOS brand.

	http://www.SafeRTOS.com - High Integrity Systems also provide a safety
	engineered and independently SIL3 certified version for use in safety and
	mission critical applications that require provable dependability.
	*/


	#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 = ( unsigned portBASE_TYPE ) 0U;
	}
	/-----------------------------------------------------------/

	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 )++;
	}
	/-----------------------------------------------------------/

	unsigned portBASE_TYPE uxListRemove( 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 )--;

	return pxList->uxNumberOfItems;
	}
	/-----------------------------------------------------------/