Collapse all Symbian^3 Product Developer Library

 

examples/Base/IPC/Async/Fibonacci1/Fibonacci1.cpp

// Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
// Example wraps a console in an active object.
// Calculates Fibonacci number as chosen by the user. Note that, in this
// example, the calculation is done as part of the console active object's 
// RunL() and can take a long time to complete. It also means that nothing
// else can happen (including responding to keyboard events) until the 
// calculation is complete. 
//



#include <e32base.h>
#include <e32cons.h>
#include <e32std.h>


LOCAL_D CConsoleBase* console;

_LIT(KTxtMainInstructions,"\n\nPress 'F' to start\n      'ESC' to exit.\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 CExampleScheduler : public CActiveScheduler
        {
public:
        void Error (TInt aError) const;
        void WaitForAnyRequest();
        void SetActiveObject(CActiveConsole* aActiveConsole);
private:
          // data members defined for this class
        CActiveConsole* iActiveConsole;
        };


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

class TFibonacciEngine
        {
public:
        void Calculate (TInt aTerms) ;

        TInt iResult ;
        } ;


//
// -----> CFibonacciApplication (definition)
//
// This class encapsulates the fibonacci calculation engine
//

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

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

          // service request
        void ProcessKeyPress(TChar aChar) ;

private:
        CConsoleBase* iConsole ;
        TFibonacciEngine iFibonacciEngine ;
        };


//
// -----> 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;
        }


// CFibonacciApplication 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 ;
                if (input == 'c') value = -1;
                }
        while (input != EKeyEnter && input != 'c') ;

        return value ;
        }


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

CFibonacciApplication::CFibonacciApplication(CConsoleBase* aConsole )
        : CActiveConsole(aConsole)
          // construct zero-priority active object
        {
        iConsole = aConsole ;
        __DECLARE_NAME(_S("CFibonacciApplication"));
        } 


CFibonacciApplication* CFibonacciApplication::NewLC(CConsoleBase* aConsole )
        {
        CFibonacciApplication* self=new (ELeave) CFibonacciApplication(aConsole);
        CleanupStack::PushL(self);
        self->ConstructL();
        return self;
        }


void CFibonacciApplication::ConstructL()
        {
          // Add to active scheduler
        CActiveScheduler::Add(this);
          // Make this the active object
        ((CExampleScheduler*)(CActiveScheduler::Current()))->SetActiveObject(this);
        }


void CFibonacciApplication::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"
          //   cancel any outstanding request
          //   issue a fibonacci request.
        if (aChar == 'f' || aChar == 'F') 
                {
                _LIT(KTxtStartingFibonacci,"\nStarting Fibonacci....  \n");
                _LIT(KTxtReturnTermNumber,"\nENTER selects number, and starts calculation\nUP    arrow increases num\nDOWN  arrow decreases num\nC     cancels\n\n");
                _LIT(KTxtCalculating,"\nCalculating...\n");
                _LIT(KFormat2,"\nResult : %u \n");
                _LIT(KTxtCancelled,"Cancelled");

                iConsole->Printf(KTxtStartingFibonacci);
                
                TInt iterations = GetValueFromKeyboard(5,1,2,46, KTxtReturnTermNumber, iConsole) ;
                if (iterations == -1)  // convenient if awkward but allows us to indicate a request to cancel.
                        {
                        iConsole->Printf(KTxtCancelled);
                        iConsole->Printf(KTxtMainInstructions);
                        return;
                        }

                iConsole->Printf(KTxtCalculating);
                iFibonacciEngine.Calculate(iterations);
                
                iConsole->Printf(KFormat2, iFibonacciEngine.iResult) ;
                iConsole->Printf(KTxtMainInstructions);
                return;
                }

       // any other key ignore
        _LIT(KTxtNotRecognised,"\nUnwanted key pressed");
        iConsole->Printf(KTxtNotRecognised);
        iConsole->Printf(KTxtMainInstructions);
        }

//
// -----> TFibonacciEngine (implementation)
//

void TFibonacciEngine::Calculate (TInt aTerms) 
        {
        TInt iterations = aTerms ;

        TInt currentTotal = 1 ;
        TInt previousTotal = 0 ;
        _LIT(KTxtTooManyIterations,"Too many iterations");
        __ASSERT_ALWAYS(iterations<47,User::Panic(KTxtTooManyIterations,iterations));

        // if limit not yet reached
        while (iterations-- > 0)        
                {
                // calculate next number in series
                TInt newTotal = currentTotal + previousTotal ;

                // update variables
                previousTotal = currentTotal ;
                currentTotal = newTotal ;

                // introduce a delay
                User::After(1000000) ;
                }  

        iResult = currentTotal ;

        } 


// 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(KTxtFibSingActObj,"Single Active Object");
        console=Console::NewL(KTxtFibSingActObj, 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
        CExampleScheduler*  exampleScheduler = new (ELeave) CExampleScheduler;

          // Push onto the cleanup stack
        CleanupStack::PushL(exampleScheduler);
         
          // Install as the active scheduler
        CActiveScheduler::Install(exampleScheduler);

          // Create CFibonacciApplication active object.
        CFibonacciApplication* fibonacci = CFibonacciApplication::NewLC(console);

          // issue initial request
        fibonacci->RequestCharacter() ;
                        
        // Main part of the program:
        //    wait loop that cycles until ActiveScheduler::Stop called
        CActiveScheduler::Start();

        // Remove from the cleanup stack and destroy:
        // 1. the CFibonacciApplication active object.
        // 2. exampleScheduler
        CleanupStack::PopAndDestroy(); 
        CleanupStack::PopAndDestroy(); 
        }

---

Copyright ©2010 Nokia Corporation and/or its subsidiary(-ies).
All rights reserved. Unless otherwise stated, these materials are provided under the terms of the Eclipse Public License v1.0.