fibonacci3.cpp

Symbain mobile code 手机应用程序源代码--基本结构方面

// Fibonacci3.CPP
//
// Copyright (C) Symbian Software Ltd 1997-2005.  All rights reserved.
//


// Example wraps a console in an active object and performs the 
// Fibonacci calculation as a background active object.
//
// The technique used is similar to, but not identical, to that used by CIdle, where
// the background active object is repeatedly called provided the other (higher priority)
// active objects are not ready to run. 
//
//
//  Fibonacci Active Objects example
//
#include <e32cons.h>
#include <e32base.h>
#include <e32std.h>

////testing only - can remove this & ModifyLedMask calls
//nclude <e32hal.h>


LOCAL_D CConsoleBase* console;

_LIT(KTxtMainInstructions,"\n\nPress 'F' to start\n      'ESC' to exit\n      'C' to cancel, anytime\n");

//////////////////////////////////////////////////////////////////////////////
//
// -----> CActiveConsole (definition)
//
// An abstract class which provides the facility to issue key requests. 
//
//////////////////////////////////////////////////////////////////////////////
class CActiveConsole : public CActive
	{
public:
	  // Construction
	CActiveConsole(CConsoleBase* aConsole);
	void ConstructL();

	  // Destruction
	~CActiveConsole();

	  // Issue request
	void RequestCharacter();
	
	  // Cancel request.
	  // Defined as pure virtual by CActive;
	  // implementation provided by this class.
	void DoCancel();

	  // Service completed request.
	  // Defined as pure virtual by CActive;
	  // implementation provided by this class,
	void RunL();

	  // Called from RunL() - an implementation must be provided
	  // by derived classes to handle the completed request
	virtual void ProcessKeyPress(TChar aChar) = 0; 
	  
protected:
	  // Data members defined by this class
	CConsoleBase* iConsole; // A console for reading from
	};


//////////////////////////////////////////////////////////////////////////////
//
// -----> CExampleScheduler (definition)
//
//////////////////////////////////////////////////////////////////////////////
class CActiveConsole;

class CExampleScheduler : public CActiveScheduler
	{
public:
	void Error (TInt aError) const;
	void WaitForAnyRequest();
	void SetActiveObject(CActiveConsole* aActiveConsole);
private:
	  // data members defined for this class
	CActiveConsole* iActiveConsole;
	};



//////////////////////////////////////////////////////////////////////////////
//
// -----> CFibonacciEngine (definition)
//
// This class provides the fibonacci calculation engine
//
//////////////////////////////////////////////////////////////////////////////

class CFibonacciEngine : public CBase
	{
public:
	CFibonacciEngine() ;
	void StartCalculate (TInt aTerms) ;
	void StepCalculate () ;
	
	TUint iResult ;

	enum TEngineState {eInactive, eCalculating, eCompleted}   ;
	TEngineState iState ;

private:
	TUint iCurrentTotal ;
	TUint iPreviousTotal ;
	TInt iTermsLeftToDo ;
	} ;


//////////////////////////////////////////////////////////////////////////////
//
// -----> CFibonacciApplication (definition)
//
// This class encapsulates the fibonacci thread that runs the fibonacci engine
//
//////////////////////////////////////////////////////////////////////////////

class CFibonacciApplication : public CActive
	{
public:
	CFibonacciApplication(CConsoleBase* aConsole, CFibonacciEngine* aFibonacciEngine) ;
	~CFibonacciApplication() ;

	void CalculateFibonacci(TInt aIterations) ;

private:
	void DoCancel() ;
	void RunL() ;

private:
	CConsoleBase* iConsole ;
	CFibonacciEngine* iFibonacciEngine ;
	} ;


//////////////////////////////////////////////////////////////////////////////
//
// -----> CFibonacciKeyHandler (definition)
//
// This class encapsulates the fibonacci keyboard handler
//
//////////////////////////////////////////////////////////////////////////////

class CFibonacciKeyHandler : public CActiveConsole
	{
public:
	CFibonacciKeyHandler(   CConsoleBase* aConsole, 
							CFibonacciApplication* aApplication) ;
	void ConstructL();

	  // Static construction
	static CFibonacciKeyHandler* NewLC(CConsoleBase* aConsole, CFibonacciApplication* aHandler) ;

	  // service request
	void ProcessKeyPress(TChar aChar) ;

private:
	CConsoleBase* iConsole ;
	CFibonacciApplication* iApplication ;
	};


//////////////////////////////////////////////////////////////////////////////
//
// -----> CActiveConsole (implementation)
//
//////////////////////////////////////////////////////////////////////////////
CActiveConsole::CActiveConsole( CConsoleBase* aConsole) 
	: CActive(CActive::EPriorityUserInput)
	  // Construct high-priority active object
	{
	iConsole = aConsole;
	__DECLARE_NAME(_S("CActiveConsole"));

	}

void CActiveConsole::ConstructL()
	{
	  // Add to active scheduler
	CActiveScheduler::Add(this);
	}

CActiveConsole::~CActiveConsole()
	{
	// Make sure we're cancelled
	Cancel();
	}

void  CActiveConsole::DoCancel()
	{
	iConsole->ReadCancel();
	}

void  CActiveConsole::RunL()
	{
	  // Handle completed request
	ProcessKeyPress(TChar(iConsole->KeyCode()));
	}

void CActiveConsole::RequestCharacter()
	{
	  // A request is issued to the CConsoleBase to accept a
	  // character from the keyboard.
	iConsole->Read(iStatus); 
	SetActive();
	}


//////////////////////////////////////////////////////////////////////////////
//
// -----> CExampleScheduler (implementation)
//
//////////////////////////////////////////////////////////////////////////////
void CExampleScheduler::Error(TInt aError) const
	{
	_LIT(KTxtSchedulerError,"CExampleScheduler - error");
	User::Panic(KTxtSchedulerError,aError);
	}


void CExampleScheduler::WaitForAnyRequest()
	{
	if (!(iActiveConsole->IsActive()))
		iActiveConsole->RequestCharacter();     
	CActiveScheduler::WaitForAnyRequest();
	}

void CExampleScheduler::SetActiveObject(CActiveConsole* aActiveConsole)
	{
	iActiveConsole = aActiveConsole;
	}



/////////////////////////////////////////////////////////////////////////////////
// CFibonacciKeyHandler support routine
//   uses up arrow & down arrow to change number, Enter to select
/////////////////////////////////////////////////////////////////////////////////

TInt GetValueFromKeyboard (TInt aInitial, TInt aStep, TInt lowerLimit, TInt upperLimit, const TDesC& aPrompt, CConsoleBase* aConsole)
	{
	TChar input ;
	TInt value = aInitial ;

	aConsole->Printf(aPrompt) ;
	do
		{
		aConsole->SetPos(0);
		_LIT(KFormat1,"%d  ");
		aConsole->Printf(KFormat1, value);
		input = aConsole->Getch() ;
		if (input == EKeyUpArrow && value < upperLimit) value = value + aStep ;
		if (input == EKeyDownArrow && value > lowerLimit) value = value - aStep ;
		}
	while (input != EKeyEnter) ;

	return value ;
	}


//////////////////////////////////////////////////////////////////////////////
//
// -----> CFibonacciKeyHandler (implementation)
//
//////////////////////////////////////////////////////////////////////////////

CFibonacciKeyHandler::CFibonacciKeyHandler(CConsoleBase* aConsole, CFibonacciApplication* aApplication)
	: CActiveConsole(aConsole)