/*

* 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: 

*

*/

#include "asn1dec.h"

EXPORT_C TASN1DecGeneric::TASN1DecGeneric(const TDesC8& aSource):

 iEncoding(aSource)

	{

	}

EXPORT_C void TASN1DecGeneric::InitL()

// x209 6.2, 6.3

	{

	if(iEncoding.Length() < KASN1ObjectMinLength)

		{

		User::Leave(KErrArgument);

		}	

	TInt i=iEncoding[0];

	TInt b=i>>6;

	iClass=(TASN1Class)b;

	TInt Length=0;

	TInt LengthOfLength=1;

	TInt Pos=0;

	TInt T=0;

	TInt encodingLength = iEncoding.Length();

	// work out tag 

	if ((iEncoding[Pos]&0x1f)==0x1f)

		{

		// tag greater than 30

		Pos++;

		if (encodingLength <= Pos+1)

			{

			User::Leave(KErrArgument);

			}

		while (iEncoding[Pos]>=128)

			{

			T<<=7;

			T+=(TUint8)(iEncoding[Pos]&127);		// this raises warning if TTagType is TUint8

			Pos++;

			if (encodingLength <= Pos+1)

				{

				User::Leave(KErrArgument);

				}

			}

		T<<=7;

		T+=(TUint8)iEncoding[Pos];

		}

	else

		{

		T=(TUint8)(iEncoding[Pos]&0x1f);

		}

	iExplicitTag = T;

	Pos++;

	TUint8 l = iEncoding[Pos];

	if (l > 128)

		{

		// this is a length of length

		if (encodingLength <= Pos+1)

			{

			User::Leave(KErrArgument);

			}

		LengthOfLength=iEncoding[Pos++]&127;

		Length=0;

		while (LengthOfLength)

			{

			if (encodingLength <= Pos+1)

				{

				User::Leave(KErrArgument);

				}

			Length<<=8;

			Length+=iEncoding[Pos++];

			LengthOfLength--;

			}

		}

	if (l == 128)

		{

		//this is constructed, indefinite length: we don't support this

		User::Leave(KErrNotSupported);

		}

	if (l < 128)

		{

		//this is a straight length

		Length = iEncoding[Pos++];

		}

	if (((Length+Pos)>encodingLength) || (Length < 0))

		{

		User::Leave(KErrArgument);

		}

	iStartOfContents = Pos;

	iLength = Length;

	}

EXPORT_C TPtrC8 TASN1DecGeneric::GetContentDER(void) const

	{

	return iEncoding.Mid(iStartOfContents, iLength);

	}

EXPORT_C TInt TASN1DecGeneric::LengthDER(void) const

	{

	return iLength+iStartOfContents;

	}

EXPORT_C TInt TASN1DecGeneric::LengthDERContent(void) const

	{

	return iLength;

	}

EXPORT_C TInt TASN1DecGeneric::LengthDERHeader() const

	{

	return LengthDER() - LengthDERContent();

	}

EXPORT_C TPtrC8 TASN1DecGeneric::Encoding() const

	{

	return iEncoding.Left(LengthDER());

	}

EXPORT_C TTagType TASN1DecGeneric::Tag() const

// we can inline this

	{

	return iExplicitTag;

	}

EXPORT_C TASN1Class TASN1DecGeneric::Class() const

// we can inline this

	{

	return iClass;

	}