/*+
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* Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).+
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* All rights reserved.+
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* This component and the accompanying materials are made available+
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* under the terms of the License "Eclipse Public License v1.0"+
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* which accompanies this distribution, and is available+
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* at the URL "http://www.eclipse.org/legal/epl-v10.html".+
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*+
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* Initial Contributors:+
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* Nokia Corporation - initial contribution.+
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*+
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* Contributors:+
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*+
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* Description: +
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* This file contains the implementation for class encoding bit strings in ASN1 DER.+
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*+
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*/+
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+
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+
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/**+
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 @file+
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*/+
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+
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#include <asn1enc.h>+
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+
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EXPORT_C CASN1EncBitString* CASN1EncBitString::NewLC(const TDesC8& aBitStr)+
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	{+
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	CASN1EncBitString* self = new (ELeave) CASN1EncBitString();+
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	CleanupStack::PushL(self);+
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	self->ConstructL(aBitStr);+
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	return self;+
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	}+
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+
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EXPORT_C CASN1EncBitString* CASN1EncBitString::NewL(const TDesC8& aBitStr)+
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	{+
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	CASN1EncBitString* self = NewLC(aBitStr);+
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	CleanupStack::Pop(self);+
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	return self;+
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	}+
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+
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EXPORT_C CASN1EncBitString* CASN1EncBitString::NewLC(const TDesC8& aBitStr, +
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													 TUint aLengthBits)+
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	{+
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	CASN1EncBitString* self = new (ELeave) CASN1EncBitString();+
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	CleanupStack::PushL(self);+
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	self->ConstructL(aBitStr, aLengthBits);+
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	return self;+
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	}+
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+
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EXPORT_C CASN1EncBitString* CASN1EncBitString::NewL(const TDesC8& aBitStr, +
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													TUint aLengthBits)+
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	{+
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	CASN1EncBitString* self = NewLC(aBitStr, aLengthBits);+
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	CleanupStack::Pop(self);+
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	return self;+
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	}+
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+
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EXPORT_C CASN1EncBitString* CASN1EncBitString::NewL(const CASN1EncBase& aEncObj)+
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	{+
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	CASN1EncBitString* self = NewLC(aEncObj);+
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	CleanupStack::Pop(self);+
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	return self;+
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	}+
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+
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EXPORT_C CASN1EncBitString* CASN1EncBitString::NewLC(const CASN1EncBase& aEncObj)+
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	{+
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	CASN1EncBitString* self = new (ELeave) CASN1EncBitString();+
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	CleanupStack::PushL(self);+
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	self->ConstructL(aEncObj);+
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	return self;+
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	}+
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+
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EXPORT_C CASN1EncBitString::~CASN1EncBitString()+
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	{+
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	delete iContents;+
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	}+
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+
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CASN1EncBitString::CASN1EncBitString()+
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: CASN1EncPrimitive(EASN1BitString),+
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  iPadding(0)+
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	{+
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	}+
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+
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void CASN1EncBitString::ConstructL(const TDesC8& aBitStr)+
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	{+
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	iContents = aBitStr.AllocL();+
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	CASN1EncPrimitive::ConstructL();+
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	}+
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+
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void CASN1EncBitString::ConstructL(const TDesC8& aBitStr, TUint aLengthBits)+
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	{+
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	iContents = aBitStr.AllocL();+
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	CASN1EncPrimitive::ConstructL();+
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	TUint totalBits = aBitStr.Length() * 8;+
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	__ASSERT_ALWAYS(aLengthBits <= totalBits, User::Leave(KErrArgument));+
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	iPadding = (TUint8)(totalBits - aLengthBits);+
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	if(iPadding > 7)+
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		User::Leave(KErrArgument);+
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	}+
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+
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/**+
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 * @internalTechnology+
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 * Constructs bit string from ASN.1 encoding object.+
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 * @param aEncObj ASN.1 encoding object to wrap in bit string.+
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 * @note First produces raw DER encoding from the object, then creates +
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 *     a bit string using other construct function.+
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 */+
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void CASN1EncBitString::ConstructL(const CASN1EncBase& aEncObj)+
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	{+
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	// produce raw DER encoding from the created ASN.1 encoding+
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	TUint len = aEncObj.LengthDER();+
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	HBufC8* intDer = HBufC8::NewMaxLC(len);+
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	TPtr8 ptrDer = intDer->Des();+
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	TUint pos = 0;+
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	aEncObj.WriteDERL(ptrDer, pos);+
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	// wrap the produced DER encoding into a bit string+
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	ConstructL(*intDer);+
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	// cleanup+
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	CleanupStack::PopAndDestroy(intDer);+
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	}+
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+
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/** +
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 * @internalTechnology +
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 * Calculates length of DER-encoded bit string contents. For non empty+
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 * bit strings this differs from octet string in the extra leading byte +
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 * containing the number of unused bits in the last octet.+
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 */+
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void CASN1EncBitString::CalculateContentsLengthDER()+
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	{+
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	iContentsLengthDER = iContents->Length();+
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	if (iContentsLengthDER > 0)+
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		{+
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		iContentsLengthDER++;+
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		}+
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	}+
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+
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/**+
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 * @internalTechnology +
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 * Writes DER-encoded bit string contents to aBuf. Prepends +
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 * the actual bit string octets with extra octet containing +
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 * number of unused bits in the last octet. Before writing, +
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 * converts contents of the bit string to big-endian form.+
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 * @param aBuf Buffer to write to; must be long enough; +
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 *     see #CalculateContentsLengthDER method.+
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 */+
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void CASN1EncBitString::WriteContentsDERL(TDes8& aBuf) const+
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	{+
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	if (iContents->Length() > 0)+
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		{+
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		aBuf[0] = iPadding;+
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		TUint len = iContents->Length();+
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		// We do not need to swap bits, as it is already done.+
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		aBuf.Replace(1, len, *iContents);		+
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		}+
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	else+
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		{+
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		// no padding octet for the empty bit string+
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		aBuf.SetLength(0);+
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		}+
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	}+
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