/*

* Copyright (c) 1998-2009 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: 

* This file contains the object implementing the Bitstring ASN1 object.

* There is no handling for constructed form of Bitstring right now.

*

*/

#include "asn1dec.h"

EXPORT_C TASN1DecBitString::TASN1DecBitString(void)

	{

	}

EXPORT_C HBufC8* TASN1DecBitString::DecodeDERL(const TDesC8& /*aSource*/,TInt& /*aPos*/)

	{

	User::Leave(KErrNotSupported);

	return NULL;

	}

EXPORT_C HBufC8* TASN1DecBitString::DecodeDERL(const TASN1DecGeneric& /*aSource*/)

	{

	User::Leave(KErrNotSupported);

	return NULL;

	}

EXPORT_C HBufC8* TASN1DecBitString::ExtractOctetStringL(const TDesC8& aSource,TInt& aPos)

	{

	TASN1DecGeneric gen(aSource.Right(aSource.Length() - aPos));

	gen.InitL();

	HBufC8* res = ExtractOctetStringL(gen);

	aPos+=gen.LengthDER();

	return res;

	}

EXPORT_C HBufC8* TASN1DecBitString::ExtractOctetStringL(const TASN1DecGeneric& aSource)

	{

	TPtrC8 encoding = aSource.GetContentDER();

	// Special case. The empty bit string. (No padding length octet)

	if (encoding.Length() == 0 )

		{

		return encoding.AllocL();				

		}

	// Length must either be 0 for the empty string or >= 2 because

	// of the padding length octet.

	if (encoding.Length() == 1)

		{

		User::Leave(KErrArgument);

		}

	TUint8 paddingLength = encoding[0];

	if (paddingLength > 7)

		{

		User::Leave(KErrArgument);

		}

	TPtrC8 pEncoding = encoding.Right(encoding.Length()-1);

	HBufC8* octetStr = pEncoding.AllocL();

	TPtr8 pEncKey = octetStr->Des();

	//stop stupid compiler warning

	TUint8 mask =(TUint8)(255 << paddingLength);

	//stop stupid compiler warning

	pEncKey[pEncKey.Length()-1] = (TUint8) ((pEncKey[pEncKey.Length()-1]) & mask);

	return octetStr;

	}