sl@0: /*
sl@0: * Copyright (c) 2001-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of the License "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description: 
sl@0: * Implementation for TASN1EncBase128 class.
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: #include "base128enc.h"
sl@0: 
sl@0: 
sl@0: TASN1EncBase128DER::TASN1EncBase128DER(TUint aInt) : iInt(aInt), iLengthDER(0)
sl@0: 	{
sl@0: 	CalculateLengthDER();
sl@0: 	}
sl@0: 
sl@0: 
sl@0: TUint TASN1EncBase128DER::LengthDER() const
sl@0: 	{
sl@0: 	return iLengthDER;
sl@0: 	}
sl@0: 
sl@0: 
sl@0: void TASN1EncBase128DER::CalculateLengthDER()
sl@0: 	{
sl@0: 	iLengthDER = 1;
sl@0: 	TUint working = iInt;
sl@0: 	while (working >>= 7)
sl@0: 		{
sl@0: 		++iLengthDER;
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: 
sl@0: void TASN1EncBase128DER::WriteDERL(TDes8& aBuf, TUint& aPos) const
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aBuf.Length() - aPos >= STATIC_CAST(TUint8, iLengthDER), 
sl@0: 		User::Leave(KErrBadDescriptor));
sl@0: 
sl@0: 	TInt last = aPos + iLengthDER - 1;
sl@0: 	TUint working = iInt;
sl@0: 	for (TUint cursor = last; cursor >= aPos; --cursor)
sl@0: 		{
sl@0: 		// Cast takes least significant 8 bits only (actually, we only need 7)
sl@0: 		aBuf[cursor] = STATIC_CAST(TUint8, working);
sl@0: 		aBuf[cursor] |= 0x80; // Top bit always set to 1...
sl@0: 		working >>= 7;
sl@0: 		}
sl@0: 	// ...except top bit on last byte is 0
sl@0: 	aBuf[last] &= 0x7F;
sl@0: 
sl@0: 	aPos += iLengthDER;
sl@0: 	}