/*

 * 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 the class encoding Big Integers in ASN1 DER

 *

 */

 #include <asn1enc.h>

 #include <bigint.h>

 EXPORT_C CASN1EncBigInt* CASN1EncBigInt::NewLC(const TInteger& aInteger)

 	{

 	CASN1EncBigInt* self = new (ELeave) CASN1EncBigInt();

 	CleanupStack::PushL(self);

 	self->ConstructL(aInteger);

 	return self;

 	}

 EXPORT_C CASN1EncBigInt* CASN1EncBigInt::NewL(const TInteger& aInteger)

 	{

 	CASN1EncBigInt* self = NewLC(aInteger);

 	CleanupStack::Pop(self);

 	return self;

 	}

 EXPORT_C CASN1EncBigInt::~CASN1EncBigInt()

 	{

 	delete iContents;

 	}

 CASN1EncBigInt::CASN1EncBigInt()

 : CASN1EncPrimitive(EASN1Integer)

 	{

 	}

 void CASN1EncBigInt::ConstructL(const TInteger& aInteger)

 {

 	iContents = aInteger.BufferLC();

 	CleanupStack::Pop(); // We take ownership of the contents

 	// May wish to skip leading byte(s) if they're unnecessary - use

 	// iWriteContents to point to the minimal part of Contents, that we'll actually use.

 	TInt last = iContents->Length() - 1;

 	TInt first = 0;

 //	if (aInteger >= 0)	//	Only signed integers now...

 //		{

 		while (first < last

 			&& (*iContents)[first] == 0

 			&& !((*iContents)[first + 1] & 0x80))

 			{

 			++first;

 			}

 //		}

 /*	else

 		{

 		while (first < last

 			&& (*iContents)[first] == 0xFF

 			&& (*iContents)[first + 1] & 0x80)

 			{

 			++first;

 			}

 		}

 */

 		//to encode positive integers correctly add a leading zero byte

 		//if the first bit is set DEF038956

 		if (iContents->Length() != 0)

 			{

 			if ((*iContents)[first] & 0x80)

 				{

 				_LIT8(KPadZero, "\0");

 				TPtr8 ptr = iContents->Des();

 				//check if the buffer does not have enough space to insert a byte

 				if (ptr.Length() == ptr.MaxLength())

 					{

 					iContents = iContents->ReAllocL(iContents->Length() + 1);

 					TPtr8 reallocptr = iContents->Des();

 					reallocptr.Insert(0, KPadZero);

 					}

 				else

 					ptr.Insert(0, KPadZero);

 				}

 			}

 	iWriteContents.Set(iContents->Mid(first));

 	CASN1EncPrimitive::ConstructL();

 	}

 void CASN1EncBigInt::CalculateContentsLengthDER()

 	{

 	iContentsLengthDER = iWriteContents.Length();

 	}

 void CASN1EncBigInt::WriteContentsDERL(TDes8& aBuf) const

 	{

 	aBuf.Copy(iWriteContents);

 	}