esp-idf/components/freertos/list.c

/*
    FreeRTOS V8.2.0 - Copyright (C) 2015 Real Time Engineers Ltd.
    All rights reserved

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    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.  Full license text is available on the following
    link: http://www.freertos.org/a00114.html

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that is more than just the market leader, it     *
     *    is the industry's de facto standard.                               *
     *                                                                       *
     *    Help yourself get started quickly while simultaneously helping     *
     *    to support the FreeRTOS project by purchasing a FreeRTOS           *
     *    tutorial book, reference manual, or both:                          *
     *    http://www.FreeRTOS.org/Documentation                              *
     *                                                                       *
    ***************************************************************************

    http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading
	the FAQ page "My application does not run, what could be wrong?".  Have you
	defined configASSERT()?

	http://www.FreeRTOS.org/support - In return for receiving this top quality
	embedded software for free we request you assist our global community by
	participating in the support forum.

	http://www.FreeRTOS.org/training - Investing in training allows your team to
	be as productive as possible as early as possible.  Now you can receive
	FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
	Ltd, and the world's leading authority on the world's leading RTOS.

    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool, a DOS
    compatible FAT file system, and our tiny thread aware UDP/IP stack.

    http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
    Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

    http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
    Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and commercial middleware.

    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.

    1 tab == 4 spaces!
*/


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


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

void vListInitialise( List_t * const 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 = ( ListItem_t * ) &( pxList->xListEnd );			/*lint !e826 !e740 The mini list structure is used as the list end to save RAM.  This is checked and valid. */

	/* 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 = ( ListItem_t * ) &( pxList->xListEnd );	/*lint !e826 !e740 The mini list structure is used as the list end to save RAM.  This is checked and valid. */
	pxList->xListEnd.pxPrevious = ( ListItem_t * ) &( pxList->xListEnd );/*lint !e826 !e740 The mini list structure is used as the list end to save RAM.  This is checked and valid. */

	pxList->uxNumberOfItems = ( UBaseType_t ) 0U;

	/* Write known values into the list if
	configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
	listSET_LIST_INTEGRITY_CHECK_1_VALUE( pxList );
	listSET_LIST_INTEGRITY_CHECK_2_VALUE( pxList );
}
/*-----------------------------------------------------------*/

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

	/* Write known values into the list item if
	configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
	listSET_FIRST_LIST_ITEM_INTEGRITY_CHECK_VALUE( pxItem );
	listSET_SECOND_LIST_ITEM_INTEGRITY_CHECK_VALUE( pxItem );
}
/*-----------------------------------------------------------*/

void vListInsertEnd( List_t * const pxList, ListItem_t * const pxNewListItem )
{
ListItem_t * const pxIndex = pxList->pxIndex;

	/* Only effective when configASSERT() is also defined, these tests may catch
	the list data structures being overwritten in memory.  They will not catch
	data errors caused by incorrect configuration or use of FreeRTOS. */
	listTEST_LIST_INTEGRITY( pxList );
	listTEST_LIST_ITEM_INTEGRITY( pxNewListItem );

	/* 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
	listGET_OWNER_OF_NEXT_ENTRY(). */
	pxNewListItem->pxNext = pxIndex;
	pxNewListItem->pxPrevious = pxIndex->pxPrevious;
	pxIndex->pxPrevious->pxNext = pxNewListItem;
	pxIndex->pxPrevious = pxNewListItem;

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

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

void vListInsert( List_t * const pxList, ListItem_t * const pxNewListItem )
{
ListItem_t *pxIterator;
const TickType_t xValueOfInsertion = pxNewListItem->xItemValue;

	/* Only effective when configASSERT() is also defined, these tests may catch
	the list data structures being overwritten in memory.  They will not catch
	data errors caused by incorrect configuration or use of FreeRTOS. */
	listTEST_LIST_INTEGRITY( pxList );
	listTEST_LIST_ITEM_INTEGRITY( pxNewListItem );

	/* Insert the new list item into the list, sorted in xItemValue order.

	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 xItemValue value) get a
	share of the CPU.  However, if the xItemValue is the same as the back marker
	the iteration loop below will not end.  Therefore the value is checked
	first, and the algorithm slightly modified if necessary. */
	if( xValueOfInsertion == portMAX_DELAY )
	{
		pxIterator = pxList->xListEnd.pxPrevious;
	}
	else
	{
		/* *** NOTE ***********************************************************
		If you find your application is crashing here then likely causes are
		listed below.  In addition see http://www.freertos.org/FAQHelp.html for
		more tips, and ensure configASSERT() is defined!
		http://www.freertos.org/a00110.html#configASSERT

			1) Stack overflow -
			   see http://www.freertos.org/Stacks-and-stack-overflow-checking.html
			2) Incorrect interrupt priority assignment, especially on Cortex-M
			   parts where numerically high priority values denote low actual
			   interrupt priorities, which can seem counter intuitive.  See
			   http://www.freertos.org/RTOS-Cortex-M3-M4.html and the definition
			   of 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, or calling an API function that does
			   not end in "FromISR" from an interrupt.
			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?).
		**********************************************************************/

		for( pxIterator = ( ListItem_t * ) &( pxList->xListEnd ); pxIterator->pxNext->xItemValue <= xValueOfInsertion; pxIterator = pxIterator->pxNext ) /*lint !e826 !e740 The mini list structure is used as the list end to save RAM.  This is checked and valid. */
		{
			/* There is nothing to do here, just iterating to the wanted
			insertion position. */
		}
	}

	pxNewListItem->pxNext = pxIterator->pxNext;
	pxNewListItem->pxNext->pxPrevious = pxNewListItem;
	pxNewListItem->pxPrevious = pxIterator;
	pxIterator->pxNext = pxNewListItem;

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

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

UBaseType_t uxListRemove( ListItem_t * const pxItemToRemove )
{
/* The list item knows which list it is in.  Obtain the list from the list
item. */
List_t * const pxList = ( List_t * ) pxItemToRemove->pvContainer;

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

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

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

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