Demo/Common/Utils/CommandInterpreter.c

/*
    FreeRTOS V7.0.2 - Copyright (C) 2011 Real Time Engineers Ltd.
	

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    This file is part of the FreeRTOS distribution.

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    the terms of the GNU General Public License (version 2) as published by the
    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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*/

/* Standard includes. */
#include <string.h>

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"

/* Utils includes. */
#include "CommandInterpreter.h"

typedef struct xCOMMAND_INPUT_LIST
{
	const xCommandLineInput *pxCommandLineDefinition;
	struct xCOMMAND_INPUT_LIST *pxNext;
} xCommandLineInputListItem;

/*
 * The callback function that is executed when "help" is entered.  This is the
 * only default command that is always present.
 */
static portBASE_TYPE prvHelpCommand( signed char *pcWriteBuffer, size_t xWriteBufferLen );

/* The definition of the "help" command.  This command is always at the front
of the list of registered commands. */
static const xCommandLineInput xHelpCommand = 
{
	( const signed char * const ) "help",
	( const signed char * const ) "help: Lists all the registered commands\r\n",
	prvHelpCommand
};

/* The definition of the list of commands.  Commands that are registered are
added to this list. */
static xCommandLineInputListItem xRegisteredCommands =
{	
	&xHelpCommand,	/* The first command in the list is always the help command, defined in this file. */
	NULL			/* The next pointer is initialised to NULL, as there are no other registered commands yet. */
};

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

portBASE_TYPE xCmdIntRegisterCommand( const xCommandLineInput * const pxCommandToRegister )
{
static xCommandLineInputListItem *pxLastCommandInList = &xRegisteredCommands;
xCommandLineInputListItem *pxNewListItem;
portBASE_TYPE xReturn = pdFAIL;

	/* Check the parameter is not NULL. */
	configASSERT( pxCommandToRegister );

	/* Create a new list item that will reference the command being registered. */
	pxNewListItem = ( xCommandLineInputListItem * ) pvPortMalloc( sizeof( xCommandLineInputListItem ) );
	configASSERT( pxNewListItem );

	if( pxNewListItem != NULL )
	{
		taskENTER_CRITICAL();
		{
			/* Reference the command being registered from the newly created 
			list item. */
			pxNewListItem->pxCommandLineDefinition = pxCommandToRegister;

			/* The new list item will get added to the end of the list, so 
			pxNext has nowhere to point. */
			pxNewListItem->pxNext = NULL;

			/* Add the newly created list item to the end of the already existing
			list. */
			pxLastCommandInList->pxNext = pxNewListItem;

			/* Set the end of list marker to the new list item. */
			pxLastCommandInList = pxNewListItem;
		}
		
		xReturn = pdPASS;
	}

	return xReturn;
}
/*-----------------------------------------------------------*/

portBASE_TYPE xCmdIntProcessCommand( const signed char * const pcCommandInput, signed char * pcWriteBuffer, size_t xWriteBufferLen  )
{
static const xCommandLineInputListItem *pxCommand = NULL;
portBASE_TYPE xReturn;

	/* Note:  This function is not re-entrant.  It must not be called from more
	thank one task. */

	if( pxCommand == NULL )
	{
		/* Search for the command string in the list of registered commands. */
		for( pxCommand = &xRegisteredCommands; pxCommand != NULL; pxCommand = pxCommand->pxNext )
		{
			if( strcmp( ( const char * ) pcCommandInput, ( const char * ) pxCommand->pxCommandLineDefinition->pcCommand ) == 0 )
			{
				/* The command has been found, the loop can exit so the command
				can be executed. */
				break;
			}
		}
	}

	if( pxCommand != NULL )
	{
		/* Call the callback function that is registered to this command. */
		xReturn = pxCommand->pxCommandLineDefinition->pxCommandInterpreter( pcWriteBuffer, xWriteBufferLen );

		/* If xReturn is pdFALSE, then no further strings will be returned
		after this one, and	pxCommand can be reset to NULL ready to search 
		for the next entered command. */
		if( xReturn == pdFALSE )
		{
			pxCommand = NULL;
		}
	}
	else
	{
		strncpy( ( char * ) pcWriteBuffer, ( const char * const ) "Command not recognised.  Enter \"help\" to view a list of available commands.\r\n\r\n", xWriteBufferLen );
		xReturn = pdFALSE;
	}

	return xReturn;
}
/*-----------------------------------------------------------*/

static portBASE_TYPE prvHelpCommand( signed char *pcWriteBuffer, size_t xWriteBufferLen )
{
static const xCommandLineInputListItem * pxCommand = NULL;
signed portBASE_TYPE xReturn;

	if( pxCommand == NULL )
	{
		/* Reset the pxCommand pointer back to the start of the list. */
		pxCommand = &xRegisteredCommands;
	}

	/* Return the next command help string, before moving the pointer on to
	the next command in the list. */
	strncpy( ( char * ) pcWriteBuffer, ( const char * ) pxCommand->pxCommandLineDefinition->pcHelpString, xWriteBufferLen );
	pxCommand = pxCommand->pxNext;

	if( pxCommand == NULL )
	{
		/* There are no more commands in the list, so there will be no more
		strings to return after this one and pdFALSE should be returned. */
		xReturn = pdFALSE;
	}
	else
	{
		xReturn = pdTRUE;
	}

	return xReturn;
}