sl@0: /*
sl@0: * Copyright (c) 2002-2009 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: * This file contains the implementation for class encoding bit strings in ASN1 DER.
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: /**
sl@0:  @file
sl@0: */
sl@0: 
sl@0: #include <asn1enc.h>
sl@0: 
sl@0: EXPORT_C CASN1EncBitString* CASN1EncBitString::NewLC(const TDesC8& aBitStr)
sl@0: 	{
sl@0: 	CASN1EncBitString* self = new (ELeave) CASN1EncBitString();
sl@0: 	CleanupStack::PushL(self);
sl@0: 	self->ConstructL(aBitStr);
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CASN1EncBitString* CASN1EncBitString::NewL(const TDesC8& aBitStr)
sl@0: 	{
sl@0: 	CASN1EncBitString* self = NewLC(aBitStr);
sl@0: 	CleanupStack::Pop(self);
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CASN1EncBitString* CASN1EncBitString::NewLC(const TDesC8& aBitStr, 
sl@0: 													 TUint aLengthBits)
sl@0: 	{
sl@0: 	CASN1EncBitString* self = new (ELeave) CASN1EncBitString();
sl@0: 	CleanupStack::PushL(self);
sl@0: 	self->ConstructL(aBitStr, aLengthBits);
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CASN1EncBitString* CASN1EncBitString::NewL(const TDesC8& aBitStr, 
sl@0: 													TUint aLengthBits)
sl@0: 	{
sl@0: 	CASN1EncBitString* self = NewLC(aBitStr, aLengthBits);
sl@0: 	CleanupStack::Pop(self);
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CASN1EncBitString* CASN1EncBitString::NewL(const CASN1EncBase& aEncObj)
sl@0: 	{
sl@0: 	CASN1EncBitString* self = NewLC(aEncObj);
sl@0: 	CleanupStack::Pop(self);
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CASN1EncBitString* CASN1EncBitString::NewLC(const CASN1EncBase& aEncObj)
sl@0: 	{
sl@0: 	CASN1EncBitString* self = new (ELeave) CASN1EncBitString();
sl@0: 	CleanupStack::PushL(self);
sl@0: 	self->ConstructL(aEncObj);
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CASN1EncBitString::~CASN1EncBitString()
sl@0: 	{
sl@0: 	delete iContents;
sl@0: 	}
sl@0: 
sl@0: CASN1EncBitString::CASN1EncBitString()
sl@0: : CASN1EncPrimitive(EASN1BitString),
sl@0:   iPadding(0)
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: void CASN1EncBitString::ConstructL(const TDesC8& aBitStr)
sl@0: 	{
sl@0: 	iContents = aBitStr.AllocL();
sl@0: 	CASN1EncPrimitive::ConstructL();
sl@0: 	}
sl@0: 
sl@0: void CASN1EncBitString::ConstructL(const TDesC8& aBitStr, TUint aLengthBits)
sl@0: 	{
sl@0: 	iContents = aBitStr.AllocL();
sl@0: 	CASN1EncPrimitive::ConstructL();
sl@0: 	TUint totalBits = aBitStr.Length() * 8;
sl@0: 	__ASSERT_ALWAYS(aLengthBits <= totalBits, User::Leave(KErrArgument));
sl@0: 	iPadding = (TUint8)(totalBits - aLengthBits);
sl@0: 	if(iPadding > 7)
sl@0: 		User::Leave(KErrArgument);
sl@0: 	}
sl@0: 
sl@0: /**
sl@0:  * @internalTechnology
sl@0:  * Constructs bit string from ASN.1 encoding object.
sl@0:  * @param aEncObj ASN.1 encoding object to wrap in bit string.
sl@0:  * @note First produces raw DER encoding from the object, then creates 
sl@0:  *     a bit string using other construct function.
sl@0:  */
sl@0: void CASN1EncBitString::ConstructL(const CASN1EncBase& aEncObj)
sl@0: 	{
sl@0: 	// produce raw DER encoding from the created ASN.1 encoding
sl@0: 	TUint len = aEncObj.LengthDER();
sl@0: 	HBufC8* intDer = HBufC8::NewMaxLC(len);
sl@0: 	TPtr8 ptrDer = intDer->Des();
sl@0: 	TUint pos = 0;
sl@0: 	aEncObj.WriteDERL(ptrDer, pos);
sl@0: 	// wrap the produced DER encoding into a bit string
sl@0: 	ConstructL(*intDer);
sl@0: 	// cleanup
sl@0: 	CleanupStack::PopAndDestroy(intDer);
sl@0: 	}
sl@0: 
sl@0: /** 
sl@0:  * @internalTechnology 
sl@0:  * Calculates length of DER-encoded bit string contents. For non empty
sl@0:  * bit strings this differs from octet string in the extra leading byte 
sl@0:  * containing the number of unused bits in the last octet.
sl@0:  */
sl@0: void CASN1EncBitString::CalculateContentsLengthDER()
sl@0: 	{
sl@0: 	iContentsLengthDER = iContents->Length();
sl@0: 	if (iContentsLengthDER > 0)
sl@0: 		{
sl@0: 		iContentsLengthDER++;
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: /**
sl@0:  * @internalTechnology 
sl@0:  * Writes DER-encoded bit string contents to aBuf. Prepends 
sl@0:  * the actual bit string octets with extra octet containing 
sl@0:  * number of unused bits in the last octet. Before writing, 
sl@0:  * converts contents of the bit string to big-endian form.
sl@0:  * @param aBuf Buffer to write to; must be long enough; 
sl@0:  *     see #CalculateContentsLengthDER method.
sl@0:  */
sl@0: void CASN1EncBitString::WriteContentsDERL(TDes8& aBuf) const
sl@0: 	{
sl@0: 	if (iContents->Length() > 0)
sl@0: 		{
sl@0: 		aBuf[0] = iPadding;
sl@0: 		TUint len = iContents->Length();
sl@0: 		// We do not need to swap bits, as it is already done.
sl@0: 		aBuf.Replace(1, len, *iContents);		
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		// no padding octet for the empty bit string
sl@0: 		aBuf.SetLength(0);
sl@0: 		}
sl@0: 	}