sl@0: /*
sl@0: * Copyright (c) 2002-2010 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of the License "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description: 
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: #include "bufferedtransformation.h"
sl@0: 
sl@0: #include <cryptospi/cryptospidef.h>
sl@0: #include <cryptopanic.h>
sl@0: #include <e32cmn.h>
sl@0: #include <cryptospi/symmetriccipherplugin.h>
sl@0: 
sl@0: #include "blocktransformation.h"
sl@0: #include "bufferedtransformationshim.h"
sl@0: #include "padding.h"
sl@0: #include "../common/inlines.h"
sl@0: 
sl@0: EXPORT_C CBufferedTransformation::~CBufferedTransformation()
sl@0: 	{
sl@0: 	delete iBT;
sl@0: 	delete iPadding;
sl@0: 	delete iInputStoreBuf;
sl@0: 	}
sl@0: 
sl@0: void CBufferedTransformation::Process(const TDesC8& aInput, TDes8& aOutput)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aOutput.MaxLength() >= MaxOutputLength(aInput.Length()), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));
sl@0: 
sl@0: 	TInt blockSize = iBT->BlockSize();
sl@0: 
sl@0: 	if ( (aInput.Size() + iInputStore.Size()) < blockSize )
sl@0: 		{
sl@0: 		iInputStore.Append(aInput);
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		TInt outputIndex = aOutput.Size();
sl@0: 		aOutput.Append(iInputStore);
sl@0: 
sl@0: 		TInt inputIndex = blockSize - iInputStore.Size();
sl@0: 		aOutput.Append(aInput.Mid(0, inputIndex));
sl@0: 
sl@0: 		TPtr8 transformBuf((TUint8*)(aOutput.Ptr()) + outputIndex, blockSize,
sl@0: 			blockSize);
sl@0: 		//This should read: 
sl@0: 		//TPtr8 transformBuf(aOutput.Mid(outputIndex, blockSize));
sl@0: 		//but in the wonderful world of descriptors, Mid returns a TPtrC8 even
sl@0: 		//when called on a TPtr8.  Fantastic eh?
sl@0: 		iBT->Transform(transformBuf);
sl@0: 
sl@0: 		outputIndex += blockSize;
sl@0: 
sl@0: 		TInt len = aInput.Size() - blockSize;
sl@0: 
sl@0: 		for (; inputIndex<=len; inputIndex+=blockSize)
sl@0: 			{
sl@0: 			aOutput.Append(aInput.Mid(inputIndex, blockSize));			
sl@0: 			transformBuf.Set((TUint8*)(aOutput.Ptr()) + outputIndex, blockSize,
sl@0: 				blockSize);
sl@0: 			iBT->Transform(transformBuf);
sl@0: 			outputIndex += blockSize;
sl@0: 			}
sl@0: 
sl@0: 		iInputStore.Zero();
sl@0: 		if (inputIndex < aInput.Size())
sl@0: 			iInputStore.Append(aInput.Mid(inputIndex));
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: TInt CBufferedTransformation::MaxOutputLength(TInt aInputLength) const
sl@0: 	{
sl@0: 	TInt rem = (aInputLength + iInputStore.Size()) % (iBT->BlockSize());
sl@0: 	return ((aInputLength + iInputStore.Size()) - rem);
sl@0: 	}
sl@0: 
sl@0: void CBufferedTransformation::Reset()
sl@0: 	{
sl@0: 	iBT->Reset();
sl@0: 	iInputStore.Zero();
sl@0: 	}
sl@0: 
sl@0: TInt CBufferedTransformation::BlockSize() const
sl@0: 	{
sl@0: 	return (iBT->BlockSize());
sl@0: 	}
sl@0: 
sl@0: TInt CBufferedTransformation::KeySize() const
sl@0: 	{
sl@0: 	return (iBT->KeySize());
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CBlockTransformation* CBufferedTransformation::BlockTransformer() const
sl@0: {
sl@0: 	return (iBT);
sl@0: }
sl@0: 
sl@0: CBufferedTransformation::CBufferedTransformation()
sl@0: 	: iInputStore(0,0,0)
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: void CBufferedTransformation::ConstructL(CBlockTransformation* aBT, CPadding* aPadding)
sl@0: 	{
sl@0: 	iInputStoreBuf = HBufC8::NewL(aBT->BlockSize());
sl@0: 	iInputStore.Set(iInputStoreBuf->Des());
sl@0: 
sl@0: 	// Take ownership last - doesn't take ownership if we leave
sl@0: 	iBT = aBT;
sl@0: 	iPadding = aPadding;
sl@0: 	}
sl@0: 
sl@0: 
sl@0: // CBufferedEncryptor
sl@0: 
sl@0: EXPORT_C CBufferedEncryptor* CBufferedEncryptor::NewL(
sl@0: 	CBlockTransformation* aBT, CPadding* aPadding)
sl@0: 	{
sl@0: 	CBufferedEncryptor* self = CBufferedEncryptorShim::NewL(aBT, aPadding);
sl@0: 	if (! self)
sl@0: 		{			
sl@0: 		// not able to use CryptoSpi, possibly due to an exterally 
sl@0: 		// derived legacy class so fallback to old implementation.			
sl@0: 		self = NewLC(aBT,aPadding);
sl@0: 		CleanupStack::Pop(self);
sl@0: 		}	
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CBufferedEncryptor* CBufferedEncryptor::NewLC(
sl@0: 	CBlockTransformation* aBT, CPadding* aPadding)
sl@0: 	{
sl@0: 	CBufferedEncryptor* self = new (ELeave) CBufferedEncryptor();
sl@0: 	CleanupStack::PushL(self);
sl@0: 	self->ConstructL(aBT, aPadding);
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: void CBufferedEncryptor::ConstructL(CBlockTransformation* aBT, CPadding* aPadding) 
sl@0: 	{
sl@0: 	CBufferedTransformation::ConstructL(aBT, aPadding);
sl@0: 	}
sl@0: 
sl@0: CBufferedEncryptor::CBufferedEncryptor()
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: void CBufferedEncryptor::ProcessFinalL(const TDesC8& aInput, TDes8& aOutput)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aOutput.MaxLength() >= MaxFinalOutputLength(aInput.Length()), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));
sl@0: 	Process(aInput, aOutput);
sl@0: 	
sl@0: 	TInt outputIndex = aOutput.Size();
sl@0: 	iPadding->PadL(iInputStore, aOutput);
sl@0: 	assert(aOutput.Size() % iBT->BlockSize() == 0);
sl@0: 
sl@0: 	TUint blockSize = iBT->BlockSize();
sl@0: 	TInt len = aOutput.Size() - outputIndex;
sl@0: 	
sl@0: 	for(TInt i=len; i>0; i-=blockSize)
sl@0: 		{
sl@0: 		TPtr8 transformBuf((TUint8*)(aOutput.Ptr()) + outputIndex, blockSize,
sl@0: 			blockSize);
sl@0: 		iBT->Transform(transformBuf);
sl@0: 		outputIndex+=blockSize;
sl@0: 		}
sl@0: 
sl@0: 	iInputStore.Zero();
sl@0: 	}
sl@0: 
sl@0: TInt CBufferedEncryptor::MaxFinalOutputLength(TInt aInputLength) const
sl@0: 	{
sl@0:     return iPadding->MaxPaddedLength(iInputStore.Size() + aInputLength);
sl@0: 	}
sl@0: 
sl@0: // CBufferedDecryptor
sl@0: 
sl@0: EXPORT_C CBufferedDecryptor* CBufferedDecryptor::NewL(
sl@0: 	CBlockTransformation* aBT, CPadding* aPadding)
sl@0: 	{
sl@0: 	CBufferedDecryptor* self = CBufferedDecryptorShim::NewL(aBT, aPadding);
sl@0: 	if (! self)
sl@0: 		{			
sl@0: 		// not able to use CryptoSpi, possibly due to an exterally 
sl@0: 		// derived legacy class so fallback to old implementation.			
sl@0: 		self = NewLC(aBT,aPadding);
sl@0: 		CleanupStack::Pop(self);
sl@0: 		}	
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CBufferedDecryptor* CBufferedDecryptor::NewLC(
sl@0: 	CBlockTransformation* aBT, CPadding* aPadding)
sl@0: 	{
sl@0: 	CBufferedDecryptor* self = new (ELeave) CBufferedDecryptor();
sl@0: 	CleanupStack::PushL(self);
sl@0: 	self->ConstructL(aBT, aPadding);
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: CBufferedDecryptor::CBufferedDecryptor()
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: void CBufferedDecryptor::ProcessFinalL(const TDesC8& aInput, TDes8& aOutput)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aOutput.MaxLength() >= MaxFinalOutputLength(aInput.Length()), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));
sl@0: 
sl@0: 	assert((aInput.Size() + iInputStore.Size()) % iPadding->BlockSize()==0);
sl@0: 	assert(aInput.Size() + iInputStore.Size() !=0 );
sl@0: 	assert(iPadding->BlockSize() % BlockSize() == 0);
sl@0: 	//1) Decrypt into aOutput up till the last full _padding_ blocksize
sl@0: 	//If this panics with descriptor problems, you've probably called
sl@0: 	//ProcessFinalL with a non-_padding_ blocksized aligned amount of data.
sl@0: 	TInt lenToDecrypt = aInput.Size() - iPadding->BlockSize();
sl@0: 	if(lenToDecrypt > 0)
sl@0: 		{
sl@0: 		Process(aInput.Left(lenToDecrypt), aOutput);
sl@0: 		assert(iInputStore.Size()==0);
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		lenToDecrypt = 0;
sl@0: 		}
sl@0: 	
sl@0: 	//2) Decrypt the last _padding_ blocksize into a new buffer
sl@0: 	HBufC8* padBuf = HBufC8::NewLC(iPadding->BlockSize());
sl@0: 	TPtr8 padPtr = padBuf->Des(); 
sl@0: 	Process(aInput.Mid(lenToDecrypt), padPtr);
sl@0: 	assert(iInputStore.Size()==0);
sl@0: 		
sl@0: 	//3) Unpad that last _padding_ blocksize into aOutput
sl@0: 	// Note that padding systems must always, like everything else in crypto,
sl@0: 	// _append_ data.
sl@0: 	iPadding->UnPadL(padPtr, aOutput);
sl@0: 
sl@0: 	CleanupStack::PopAndDestroy(padBuf);
sl@0: 	}
sl@0: 
sl@0: TInt CBufferedDecryptor::MaxFinalOutputLength(TInt aInputLength) const
sl@0: 	{
sl@0: 	return iPadding->MaxUnPaddedLength(aInputLength + iInputStore.Size());
sl@0: 	}
sl@0: 
sl@0: void CBufferedDecryptor::ConstructL(CBlockTransformation* aBT, CPadding* aPadding) 
sl@0: 	{
sl@0: 	CBufferedTransformation::ConstructL(aBT, aPadding);
sl@0: 	}