fibonacci3.cpp

Symbain mobile code 手机应用程序源代码--基本结构方面

	  // construct zero-priority active object
	{
	iConsole = aConsole ;
	iApplication = aApplication ;

	__DECLARE_NAME(_S("CFibonacciApplication"));
	  // Add to active scheduler
	CActiveScheduler::Add(this);
	  // Make this the active object
	((CExampleScheduler*)(CActiveScheduler::Current()))->SetActiveObject(this);
	} 


void CFibonacciKeyHandler::ProcessKeyPress(TChar aChar)
	{
	  // if key is ESC, cancel any outstanding request & stop the scheduler
	if (aChar == EKeyEscape)
		{
		CActiveScheduler::Stop();
		return;
		}

	  // If key is "f" or "F", issue a Fibonacci request if none is in progress
	if (aChar == 'f' || aChar == 'F') 
		{
		if (!(iApplication->IsActive()))
			{
			_LIT(KTxtReturnTermNumber,"\nENTER selects num\nUP    arrow increases num\nDOWN  arrow decreases num\n\n");
			TInt iterations = GetValueFromKeyboard(5,1,2,46, KTxtReturnTermNumber, iConsole) ;
			iApplication->CalculateFibonacci(iterations);
			}
		else
			{
			_LIT(KTxtAlreadyInProgress,"[Already in progress]");
			iConsole->Printf(KTxtAlreadyInProgress);
			}
		return;
		}

      // If key is "c" or "C", cancel any outstanding request   
	if (aChar == 'c' || aChar == 'C')
		{
		_LIT(KTxtCancelFibonacci,"\nCancelling Fibonacci....  \n");
		iConsole->Printf(KTxtCancelFibonacci);
		iApplication->Cancel();
		iConsole->Printf(KTxtMainInstructions);
		return;
		}
	
	_LIT(KTxtNotRecognised,"\nUnwanted key pressed");
	iConsole->Printf(KTxtNotRecognised);
	iConsole->Printf(KTxtMainInstructions);
	}


//////////////////////////////////////////////////////////////////////////////
//
// -----> CFibonacciApplication (implementation)
//
//////////////////////////////////////////////////////////////////////////////

CFibonacciApplication::CFibonacciApplication(CConsoleBase* aConsole, CFibonacciEngine* aFibonacciEngine)
//
// Constructor
//
	: CActive(EPriorityStandard)
	{
	iConsole = aConsole ;
	iFibonacciEngine = aFibonacciEngine ;
	CActiveScheduler::Add(this);
	__DECLARE_NAME(_S("CFibonacciApplication"));
	};


// destructor
CFibonacciApplication::~CFibonacciApplication() 
	{
	// cancel any requests and tell server 
	Cancel() ;
	}


void CFibonacciApplication::DoCancel() 
	{
	// cancel the active object request 
	iFibonacciEngine->iState = CFibonacciEngine::eInactive ;
	}



// initiate a request
void CFibonacciApplication::CalculateFibonacci(TInt aIterations)
	{
	// initialize engine
	// no neeed to set iStatus to KRequestPending, as request completes below
	iFibonacciEngine->StartCalculate(aIterations) ;

	// schedule the request
	SetActive() ;

	// send signal that this request has completed
	TRequestStatus* status = &iStatus ;
	User::RequestComplete(status, KErrNone) ;
	}



void CFibonacciApplication::RunL() 
// implements a simple state engine: {eInactive, eCalculating, eCompleted}
	{
	if (iFibonacciEngine->iState == CFibonacciEngine::eInactive )
		{
		_LIT(KTxtEngineNotInitialized,"Engine not initialized");
		User::Panic(KTxtEngineNotInitialized, KErrNotReady) ;
		}
	else if (iFibonacciEngine->iState == CFibonacciEngine::eCalculating )
		{               
		// unnecessary - just provides feedback on progression of the calculation
		_LIT(KTxtDot,".");
		iConsole->Printf(KTxtDot) ;

		// no neeed to set iStatus to KRequestPending, as request completes below

		// request next step
		iFibonacciEngine->StepCalculate() ;

		// schedule request
		SetActive() ;

		// send signal that this request has completed
		TRequestStatus* status = &iStatus ;
		User::RequestComplete(status, KErrNone) ;
		}
	else if (iFibonacciEngine->iState == CFibonacciEngine::eCompleted )
		{
		// finished calculation: print result and reset state engine
		_LIT(KFormat2,"\n    Result : %u \n");  //not used
		iConsole->Printf(KFormat2, iFibonacciEngine->iResult) ; 
		iConsole->Printf(KTxtMainInstructions) ; 
		iFibonacciEngine->iState = CFibonacciEngine::eInactive ;
		}
	}



//////////////////////////////////////////////////////////////////////////////
//
// -----> CFibonacciEngine (implementation)
//
//////////////////////////////////////////////////////////////////////////////
CFibonacciEngine::CFibonacciEngine() 
	{
	iState = eInactive ;
	}


void CFibonacciEngine::StartCalculate (TInt aTerms) 
	{
	// initialise all internal variables to initial state
	iCurrentTotal = 1 ;
	iPreviousTotal = 0 ;
	iResult = 0 ;
	iTermsLeftToDo = aTerms - 1 ;   // first step completed in variable initialization
	iState = eCalculating ;
	}



void CFibonacciEngine::StepCalculate () 
	{

	// if full calculation not yet complete, but in progress (i.e. not cancelled)
	if (--iTermsLeftToDo > 0 && iState == eCalculating)     
		{
		// calculate next number in series
		TInt newTotal = iCurrentTotal + iPreviousTotal ;

		// update internal variables
		iPreviousTotal = iCurrentTotal ;
		iCurrentTotal = newTotal ;

		// introduce a delay to make us a long-running service
		User::After(1000000) ;

		// not necessary, but allows running total to be used during the calculation
		// (say for putting values into a chart or graph)
		iResult = iCurrentTotal ;
		}
	else if (iTermsLeftToDo <= 0)
		{
		// flag that calculation has finished and ensure final result is available
		iState = eCompleted ;
		iResult = iCurrentTotal ;
		}
	} 



/////////////////////////////////////////////////////////////////////////////////
// This section deals with initialisation and ensuring we have a console active
/////////////////////////////////////////////////////////////////////////////////

void doExampleL () ;

void SetupConsoleL();

GLDEF_C TInt E32Main()                          // main function called by E32
    {
	CTrapCleanup* cleanup=CTrapCleanup::New();              // get clean-up stack
	TRAPD(error,SetupConsoleL());                           // more initialization, then do example
	_LIT(KTxtFibonacciExampleError,"Fibonacci example error");
	__ASSERT_ALWAYS(!error,User::Panic(KTxtFibonacciExampleError,error));
	delete cleanup;                                         // destroy clean-up stack
	return 0;                                                                               // and return
    }

void SetupConsoleL()                             // initialize and call example code under cleanup stack
    {
	_LIT(KTxtFibActObjBackground,"Background Active Object");
	console=Console::NewL(KTxtFibActObjBackground, TSize(KConsFullScreen,KConsFullScreen));
	CleanupStack::PushL(console);
	console->Printf(KTxtMainInstructions) ;
	TRAPD(error, doExampleL());                                                     // perform example function
	if (error)
		{
		_LIT(KFormat3,"failed: leave code=%d");
		console->Printf(KFormat3, error);
		}
	_LIT(KTxtPressAnyKey,"[Press any key to exit]");
	console->Printf(KTxtPressAnyKey);
	console->Getch();                                                               // get and ignore character
	CleanupStack::PopAndDestroy();                                  // close console
    }


//////////////////////////////////////////////////////////////////////////////
//
// Do the example
//
//////////////////////////////////////////////////////////////////////////////
void doExampleL()
    {
	  // Construct and install the active scheduler; push onto the cleanup stack
	CExampleScheduler*  exampleScheduler = new (ELeave) CExampleScheduler;
	CleanupStack::PushL(exampleScheduler);
	 
	  // Install as the active scheduler
	CActiveScheduler::Install(exampleScheduler);

	// Create CFibonacciEngine active object; push onto the cleanup stack
	CFibonacciEngine* fibEngine = new (ELeave) CFibonacciEngine ;
    CleanupStack::PushL(fibEngine);
    
	  // Create CFibonacciApplication handler active object; push onto the cleanup stack
	CFibonacciApplication* fibApplication = new CFibonacciApplication(console, fibEngine);
    CleanupStack::PushL(fibApplication);

	  // Create CFibonacciKeyHandler active object; push onto the cleanup stack
	CFibonacciKeyHandler* fibKeyHandler = new CFibonacciKeyHandler(console, fibApplication);
    CleanupStack::PushL(fibKeyHandler);

	  // issue initial request
	fibKeyHandler->RequestCharacter() ;
			
	// Main part of the program:
	//    wait loop that cycles until ActiveScheduler::Stop called
	CActiveScheduler::Start();
           
	// Remove items from the cleanup stack and destroy them
	CleanupStack::PopAndDestroy(4); 
	}