Chapter 1

void TShip::ExternalizeL(RWriteStream& aStream) const
{
aStream.WriteUint8L(iType);
aStream.WriteInt8L(iLength);
aStream.WriteInt8L(iRemaining);
aStream.WriteInt8L(iStartX);
aStream.WriteInt8L(iStartY);
aStream.WriteInt8L(iDx);
aStream.WriteInt8L(iDy);
}
The ship data is just a series of 8-bit integers. In all these functions, we don't expect the
integer values to be more than 8 bits, so we specify this is what we want to store. This saves
some space compared to storing a full 32 bits for each integer.
Finally, the controller itself externalizes some extra persistent data: namely, its state and the
current zoom factor:
void CGameController::ExternalizeL(RWriteStream& aStream) const
{
aStream.WriteUint8L(iState);
aStream.WriteInt32L(iZoomFactor);
}
Restoring the controller data
We saw that the document's RestoreL() uses the controller's restoring NewL() function
that takes CStreamStore and TStreamId arguments, which is coded as follows:
CGameController* CGameController::NewL(const CStreamStore& aStore,
{
TStreamId aStreamId)
CGameController* self = new(ELeave) CGameController;
CleanupStack::PushL(self);
self->RestoreL(aStore, aStreamId);
CleanupStack::Pop();
return self;
}
RestoreL() is private, like ConstructL(), so that it can't be accidentally called by
CGameController's clients. Here it is:
void CGameController::RestoreL(const CStreamStore& aStore, TStreamId
aStreamId)
{
iEnv = CEikonEnv::Static();
RStoreReadStream stream;