why can't convert Symbian CRSAPublicKey to descriptor?

code as following:

const CRSAPublicKey& iRSAPublicKey = mRSAKeyPair->PublicKey();
const TInteger& e = iRSAPublicKey.E();
HBufC8* exponent8 = e.BufferLC(); //failed to开发者_Python百科 get the right result,it's garbled
TInt ei = e.ConvertToLongL();    //converted successfully,ei=65537

can anyone tell me why BufferLC() doesn't work?is something important i just have missed?,and how to convert a TInterger to descriptor? thanks in advance.

It't not garbled, it just the integer's binary representation as stated in the documentation. The same way as the byte 0x33 is the binary representation for ASCII 3.

I assume you want something printable of the TInteger. For small TIntegers for which IsConvertableToLong() is true, you can use the ConvertToLong() approach with one of the TDes::AppendNum() overloads. For larger integers, I think you need to roll your own conversion function. The most straightforward way is probably just to output the binary representation bytes as hex.

Edited to add: Here's an untested snippet for doing the hex conversion.

HBufC8 *bin = theTInteger.BufferLC();

// One binary byte yields two hex bytes
HBufC8 *output = HBufC8::NewL(bin->Length()*2);
TPtr8 outP = output->Des();

// Loop through the binary bytes  
for (int i = 0; i < bin->Length(); ++i) {
  TUint8 const KHex[] = "01234567890abcdef";
  TUint8 binByte = (*bin)[i];

  // Output high nibble (4 bits)
  outP.Append(KHex[(binByte & 0xf0) >> 4]);

  // Output low nibble
  outP.Append(KHex[binByte & 0x0f]);
}

CleanupStack::PopAndDestroy(bin);