31 October 2005

Do action for all files in some directory on all drives in Symbian

In SDL there is a useful sample of how to run through all files in directory:

void ForAllMatchingFiles(RFs& aSession, const TDesC& aWildName, const TDesC& aScanDir)
TFindFile file_finder(aSession);
CDir* file_list;
TInt err = file_finder.FindWildByDir(aWildName,aScanDir, file_list);
while (err==KErrNone)
TInt i;
for (i=0; i < Count(); i++)
TParse fullentry;
fullentry.Set((*file_list)[i].iName, &file_finder.File(),NULL);

// Do something with the full Symbian OS filename

DoOneFile(aSession, fullentry.FullName());
delete file_list;

26 October 2005

Pics of Symbian smartphone Nokia N71 prototype

In the Internet show up pictures of prototype of the new Nokia Symbian-smartphone N71. Here is the link. And here is one of the pictures:

More about writable descriptor

Code in previous post about writable descriptor was related to use members of class. If you need the descriptor only in small pieceof code then you can write like this:

TPtr8 iWriteDes(iHeapDes->Des());

22 October 2005

How to convert TInt64 to string on Symbian?

Sometimes you need to display some TInt64 on screen so you need to convert it to string representation. But unfortunately you can’t display it using Format() function of Symbian descriptors. What to do? You have to use functions AppendNum() or Num() which can take as parameter TInt64. Code will look like this:

    TInt64 n = 123456789;
    TBuf<64> tInt64;
    tInt64.AppendNum( n );
    tSomeString.Format( “I have this value - %S”, &tInt64 );

20 October 2005

How to assign writable descriptor in Symbian

When you need a writable descriptor like TDes8 to pass as reference into a function ( like FillMyDes(TDes8& aDes) ), and later this function will fill it with data, you probably want to allocate this descriptor in Symbian heap. So you are writing this code:

    HBufC8* iHeapDes = HBufC8::NewL(KSIZE);

And then you want to store writable descriptor for later use like this:

    TPtr8 iWriteDes(NULL,0);
    iWriteDes = iHeapDes->Des();

But iWriteDes don’t becomes what you really wanted. Because you make mistake in previous line of code, you haven’t assigned descriptor, you just trieŠ² to copy the data contained in heap descriptor to you writable descriptor. The right code will look like this:

    iWriteDes.Set( iHeapDes->Des() );

Now you got correct writable descriptor in iWriteDes.

19 October 2005

How to kill another process by its name

This code snippet will kill process with name KPROCNAME

TFullName theName;
TFindProcess process;
while ( process.Next( theName ) != KErrNotFound )
if ( ( theName.Find( KPROCNAME ) != KErrNotFound ) )
RProcess aProcess;
aProcess.Open( process );

18 October 2005

Do you know how to convert to AMR using CMMFCodec?

This task can be tricky because of lack of the documentation on AMR-NB codec in Symbian. The following code will work on Series 60 2.0 devices:

First of all we declare missing declaration from old AmrCodec.h from Series 60 1.0 SDK:

class TAmrEncParams



inline TAmrEncParams();


TInt iMode; // encoding mode 0-7 (0=MR475,1=MR515,...,7=MR122,
default 7)

TInt iDTX; // DTX flag (TRUE or default FALSE)


TAmrEncParams::TAmrEncParams() :

iMode(7), iDTX(0) {}

And we will also declare UIDs of AMR codecs:

#define KAdvancedUidCodecPCM16ToAMR 0x101FAF68
#define KAdvancedUidCodecAMRToPCM16 0x101FAF67

This is the function that convers PCM data to AMR-NB (note that CMMFPtrBuffer class you can use only on Series 60 2.0 FP2 SDK, on earlier SDKs you have to use CMMFDescriptorBuffer). Size of aDes parameter is supposed to be equal to 320 bytes.

HBufC8* ConvertFromPCMToAMRNBL( const TPtr8& aDes, TInt aMode )


TAmrEncParams taepParams;

taepParams.iMode = aMode;

cmmfcCodec = CMMFCodec::NewL(TUid::Uid(KAdvancedUidCodecPCM16ToAMR ));

CleanupStack::PushL( cmmfcCodec );

cmmfcCodec->ConfigureL( TUid::Uid(KAdvancedUidCodecPCM16ToAMR), ( const TDesC8& ) taepParams );
ptrbPCM16 = CMMFPtrBuffer::NewL();

CleanupStack::PushL( ptrbPCM16 );

ptrbPCM16->SetPtr( aDes );

desbAMRNB = CMMFDescriptorBuffer::NewL( 32 );

CleanupStack::PushL( desbAMRNB );

TCodecProcessResult result = cmmfcCodec->ProcessL( * ptrbPCM16, * desbAMRNB );

if ( ( result.iStatus != TCodecProcessResult::EProcessComplete )

( result.iSrcBytesProcessed != ( TUint ) aDes.Length() ) )

return NULL;

CleanupStack::Pop( 2 ); // cmmfcCodec, ptrbPCM16

HBufC8* pAMRData = desbAMRNB->Data().AllocL();

CleanupStack::Pop( 1 ); // desbAMRNB

return pAMRData;