/*

* 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);

	}