/*

 * Copyright (c) 2005-2009 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: 

 *

 */

 /**

  @file

 */

 #include <e32std.h>

 #include <hash.h>

 #define EXPANDLOOP

 //

 // HMAC implementation

 //

 CHMAC::CHMAC()

 :CMessageDigest(){}

 CHMAC::CHMAC(CMessageDigest* aDigest)

 	:CMessageDigest(),

 	iDigest(aDigest),

 	iInnerPad(KMaxBlockSize),

 	iOuterPad(KMaxBlockSize)

 {}

 CHMAC::CHMAC(const CHMAC& aMD)

 	:CMessageDigest(aMD), 

 	iDigest(NULL),

 	iInnerPad(aMD.iInnerPad), 

 	iOuterPad(aMD.iOuterPad),

 	iBlockSize(aMD.iBlockSize)

 	{}

 EXPORT_C CHMAC::~CHMAC(void)

 	{

 	delete iDigest;

 	}

 EXPORT_C CHMAC* CHMAC::NewL(const TDesC8& aKey,CMessageDigest* aDigest)

 	{

 	CHMAC* self=new(ELeave) CHMAC(aDigest);

 	CleanupStack::PushL(self);

 	self->InitialiseL(aKey);

 	CleanupStack::Pop(self);

 	return self;

 	}

 void CHMAC::InitialiseL(const TDesC8& aKey)

 	{

 	InitBlockSizeL();

 	// initialisation

 	if (iDigest)

 		{

 		iDigest->Reset();

 		if( (TUint32)aKey.Size() > iBlockSize)

 			{

 			iInnerPad = iDigest->Final(aKey);

 			}

 		else 

 			{

 			iInnerPad = aKey;

 			}

 		TUint i;

 		for (i=iInnerPad.Size();i<iBlockSize;i++)

 			iInnerPad.Append(0);

 		iOuterPad=iInnerPad;

 		const TUint8 Magic1=0x36, Magic2=0x5c;

 		for (i=0;i<iBlockSize;i++)

 		{

 			iInnerPad[i]^=Magic1;

 			iOuterPad[i]^=Magic2;

 		}

 		//start inner hash

 		iDigest->Hash(iInnerPad);

 		}

 	}

 void CHMAC::InitBlockSizeL()

  	{

  	 iBlockSize = iDigest->BlockSize();

 	 if(iBlockSize > KMaxBlockSize)

 		 {

 		 User::Leave(KErrNotSupported);

 		 }

  	 iInnerPad.SetLength(iBlockSize);

  	 iOuterPad.SetLength(iBlockSize);

  	 iInnerPadCopy.SetLength(iBlockSize);

  	 iOuterPadCopy.SetLength(iBlockSize);

    	}

 EXPORT_C CMessageDigest* CHMAC::CopyL(void)

 	{

 	CHMAC* that=new(ELeave) CHMAC(*this);

 	CleanupStack::PushL(that);

 	that->iDigest=iDigest ? iDigest->CopyL() : NULL;

 	CleanupStack::Pop();

 	return that;

 	}

 EXPORT_C CMessageDigest*  CHMAC::ReplicateL(void)

 	{

 	CHMAC* that=new(ELeave) CHMAC(*this);

 	CleanupStack::PushL(that);

 	that->iDigest=iDigest ? iDigest->ReplicateL() : NULL;

 	that->Reset();

 	CleanupStack::Pop();

 	return that;

 	}

 EXPORT_C TInt CHMAC::BlockSize(void)

 	{

 	return iBlockSize;

 	}

 EXPORT_C TInt CHMAC::HashSize(void)

 	{

 	return iDigest ? iDigest->HashSize() : 0;

 	}

 EXPORT_C void CHMAC::Reset(void)

 	{

 	if (iDigest)

 		{

 		iDigest->Reset();

 		iDigest->Update(iInnerPad);

 		}

 	}

 //	JCS, There may be a more efficient method but I can't find it

 //	because using the DoFinal/DoUpdate functions directly calls

 //	Store/Restore at inappropriate times and scribbles over stored

 //	data

 //	This is the only way I've found to both generate a hash value

 //	and get this in the correctly updated state

 EXPORT_C TPtrC8 CHMAC::Hash(const TDesC8& aMessage)

 {

 	TPtrC8 ptr(KNullDesC8());

 	TPtrC8 finalPtr(KNullDesC8());

 	StoreState();

 	if (iDigest)

 	{

 		ptr.Set(iDigest->Final(aMessage));

 		iDigest->Update(iOuterPad);

 		finalPtr.Set(iDigest->Final(ptr));

 	}

 	RestoreState();

 	iDigest->Update(aMessage);

 	return (finalPtr);

 }

 EXPORT_C void CHMAC::Update(const TDesC8& aMessage)

 	{

 	if(iDigest)

 		{

 		iDigest->Update(aMessage);

 		}

 	}

 EXPORT_C TPtrC8 CHMAC::Final(const TDesC8& aMessage)

 	{

 	TPtrC8 ptr(KNullDesC8());

 	if(iDigest)

 		{

 		ptr.Set(iDigest->Final(aMessage));

 		iDigest->Update(iOuterPad);

 		iDigest->Final(ptr);

 		Reset();

 		}

 	return (ptr);

 	}

 EXPORT_C TPtrC8 CHMAC::Final()

 	{

 	TPtrC8 ptr(KNullDesC8());

 	if(iDigest)

 		{

 		ptr.Set(iDigest->Final());

 		iDigest->Update(iOuterPad);

 		iDigest->Final(ptr);

 		Reset();

 		}

 	return (ptr);

 	}

 void CHMAC::RestoreState()

 {

 	iOuterPad.Copy(iOuterPadCopy);

 	iInnerPad.Copy(iInnerPadCopy);

 	if (iDigest)

 		iDigest->RestoreState();

 }

 void CHMAC::StoreState()

 {

 	iOuterPadCopy.Copy(iOuterPad);

 	iInnerPadCopy.Copy(iInnerPad);

 	if (iDigest)

 		iDigest->StoreState();

 }