FreeRTOS-Kernel/FreeRTOS/Demo/Common/Minimal/QueueOverwrite.c

/*
    FreeRTOS V7.4.2 - 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.
*/

/*
 * Basic task to demonstrate the xQueueOverwrite() function.  See the comments
 * in the function itself.
 */

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"

/* Demo program include files. */
#include "QueueOverwrite.h"

/* A block time of 0 just means "don't block". */
#define qoDONT_BLOCK		0

/* Number of times to overwrite the value in the queue. */
#define qoLOOPS			5

/* The task that uses the queue. */
static void prvQueueOverwriteTask( void *pvParameters );

/* Variable that is incremented on each loop of prvQueueOverwriteTask() provided
prvQueueOverwriteTask() has not found any errors. */
static unsigned long ulLoopCounter = 0;

/*-----------------------------------------------------------*/

void vStartQueueOverwriteTask( unsigned portBASE_TYPE uxPriority )
{
	/* Create the test task. */
	xTaskCreate( prvQueueOverwriteTask, ( signed char * ) "QOver", configMINIMAL_STACK_SIZE, NULL, uxPriority, ( xTaskHandle * ) NULL );
}
/*-----------------------------------------------------------*/

static void prvQueueOverwriteTask( void *pvParameters )
{
xQueueHandle xQueue;
const unsigned portBASE_TYPE uxQueueLength = 1;
unsigned long ulValue, ulStatus = pdPASS, x;

	/* The parameter is not used. */
	( void ) pvParameters;

	/* Create the queue.  xQueueOverwrite() should only be used on queues that
	have a length of 1. */
	xQueue = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( unsigned long ) );
	configASSERT( xQueue );

	for( ;; )
	{
		/* The queue is empty.  Writing to the queue then reading from the queue
		should return the item written. */
		ulValue = 10;
		xQueueOverwrite( xQueue, &ulValue );

		ulValue = 0;
		xQueueReceive( xQueue, &ulValue, qoDONT_BLOCK );

		if( ulValue != 10 )
		{
			ulStatus = pdFAIL;
		}

		/* Now try writing to the queue several times.  Each time the value
		in the queue should get overwritten. */
		for( x = 0; x < qoLOOPS; x++ )
		{
			/* Write to the queue. */
			xQueueOverwrite( xQueue, &x );

			/* Check the value in the queue is that written, even though the
			queue was not necessarily empty. */
			xQueuePeek( xQueue, &ulValue, qoDONT_BLOCK );
			if( ulValue != x )
			{
				ulStatus = pdFAIL;
			}

			/* There should always be one item in the queue. */
			if( uxQueueMessagesWaiting( xQueue ) != uxQueueLength )
			{
				ulStatus = pdFAIL;
			}
		}

		/* Empty the queue again. */
		xQueueReceive( xQueue, &ulValue, qoDONT_BLOCK );

		if( uxQueueMessagesWaiting( xQueue ) != 0 )
		{
			ulStatus = pdFAIL;
		}

		if( ulStatus != pdFAIL )
		{
			/* Increment a counter to show this task is still running without
			error. */
			ulLoopCounter++;
		}
	}
}
/*-----------------------------------------------------------*/

portBASE_TYPE xIsQueueOverwriteTaskStillRunning( void )
{
portBASE_TYPE xReturn;

	if( ulLoopCounter > 0 )
	{
		xReturn = pdPASS;
	}
	else
	{
		/* The task has either stalled of discovered an error. */
		xReturn = pdFAIL;
	}

	ulLoopCounter = 0;

	return xReturn;
}