/*

* Copyright (c) 2001-2009 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: 

* Implementation for TASN1EncBase128 class.

*

*/

#include "base128enc.h"

TASN1EncBase128DER::TASN1EncBase128DER(TUint aInt) : iInt(aInt), iLengthDER(0)

	{

	CalculateLengthDER();

	}

TUint TASN1EncBase128DER::LengthDER() const

	{

	return iLengthDER;

	}

void TASN1EncBase128DER::CalculateLengthDER()

	{

	iLengthDER = 1;

	TUint working = iInt;

	while (working >>= 7)

		{

		++iLengthDER;

		}

	}

void TASN1EncBase128DER::WriteDERL(TDes8& aBuf, TUint& aPos) const

	{

	__ASSERT_DEBUG(aBuf.Length() - aPos >= STATIC_CAST(TUint8, iLengthDER), 

		User::Leave(KErrBadDescriptor));

	TInt last = aPos + iLengthDER - 1;

	TUint working = iInt;

	for (TUint cursor = last; cursor >= aPos; --cursor)

		{

		// Cast takes least significant 8 bits only (actually, we only need 7)

		aBuf[cursor] = STATIC_CAST(TUint8, working);

		aBuf[cursor] |= 0x80; // Top bit always set to 1...

		working >>= 7;

		}

	// ...except top bit on last byte is 0

	aBuf[last] &= 0x7F;

	aPos += iLengthDER;

	}