/*

* Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "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: 

*

*/

#include <e32base.h>

#include <padding.h>

#include <securityerr.h>

#include <cryptopanic.h>

/* CPaddingPKCS7 */

EXPORT_C CPaddingPKCS7* CPaddingPKCS7::NewL(TInt aBlockBytes)

	{

	__ASSERT_ALWAYS(aBlockBytes > 0, User::Leave(KErrArgument));

	return new(ELeave)CPaddingPKCS7(aBlockBytes);

	}

EXPORT_C CPaddingPKCS7* CPaddingPKCS7::NewLC(TInt aBlockBytes)

	{

	CPaddingPKCS7* self = CPaddingPKCS7::NewL(aBlockBytes);

	CleanupStack::PushL(self);

	return self;

	}

EXPORT_C CPaddingPKCS7::CPaddingPKCS7(TInt aBlockBytes):CPadding(aBlockBytes)

	{

	}

void CPaddingPKCS7::DoPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	TInt paddingBytes = BlockSize()-(aInput.Length()%BlockSize());		

	aOutput.Append(aInput);

	aOutput.SetLength(aOutput.Length()+paddingBytes);

	for (TInt i=1;i<=paddingBytes;i++)

		{

		aOutput[aOutput.Length()-i]=(TUint8)(paddingBytes);

		}

	}

void CPaddingPKCS7::UnPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	TUint inputLen = aInput.Length();

 	TUint paddingLen = (TUint)(aInput[inputLen - 1]);

	if (paddingLen > inputLen)

 		{

 		User::Leave(KErrInvalidPadding);

 		}

	TInt outlen = aInput.Length() - paddingLen;

	__ASSERT_DEBUG(aOutput.MaxLength() >= outlen, User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

	aOutput.Append(aInput.Left(outlen));

	for (TInt i=outlen;i<inputLen;i++)

		{

		//All padding bytes must equal the length of padding expected

		if (aInput[i]!=paddingLen)

			{

			User::Leave(KErrInvalidPadding);

			}

		}

	}

TInt CPaddingPKCS7::MinPaddingLength(void) const

	{

	//if aInputBytes is 1 less than the blocksize then we get 1 byte of padding

	return 1;

	}

TInt CPaddingPKCS7::MaxPaddedLength(TInt aInputBytes) const

	{

	TUint padBytes = BlockSize() - (aInputBytes % BlockSize());

	return padBytes + aInputBytes;

	}