cryptoservices/certificateandkeymgmt/asn1/bigintenc.cpp
changeset 0 2c201484c85f
child 8 35751d3474b7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cryptoservices/certificateandkeymgmt/asn1/bigintenc.cpp	Wed Jul 08 11:25:26 2009 +0100
@@ -0,0 +1,117 @@
+/*
+* 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);
+	}