/*

 * 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;

 	}