diff -r 000000000000 -r 96e5fb8b040d kernel/eka/debug/crashMonitor/src/scmchksum.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/kernel/eka/debug/crashMonitor/src/scmchksum.cpp	Thu Dec 17 09:24:54 2009 +0200
@@ -0,0 +1,168 @@
+// Copyright (c) 2008-2009 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:
+// e32\debug\crashMonitor\src\scmchksum.cpp
+// 
+//
+
+/**
+ @file
+ @internalTechnology
+*/
+
+#include <scmdatatypes.h>
+
+namespace Debug
+	{	
+	/**
+	 * Constructor
+	 */
+	TScmChecksum::TScmChecksum()
+	: iLength(0)	
+	, iSum(0)
+	, iZeroCount(0)
+		{	
+		}
+	
+	/**
+	 * ChecksumBlock - calculate checksum values for given data
+	 * @param aData - the data to checksum
+	 * @param aLen - the length of the data to checksum
+	 * @return void
+	 */
+	void TScmChecksum::ChecksumBlock(const TUint8* aData, TUint aLen)
+		{		
+		/**
+		 * 
+		 * Note there is Symbian CRC implementation to be found in the following
+		 * \src\cedar\generic\tools\e32tools\elf2e32\source\checksum.h
+		 * \src\cedar\generic\tools\e32tools\elf2e32\source\checksum.cpp
+		 * this however may be no good to us
+		 * as we need to produce a single checksum even though the entire data may be
+		 * read in different size blocks - and the entire data may not be available
+		 * (the comm port requirement is for read only )
+		 * If we do however want to use the CRC then this is the place to insert the code
+		 */		
+		if(!aData)
+			{
+			return;
+			}
+			
+		for(TUint i=0;i<aLen;i++)
+			{
+			TUint8 val = *(aData+i);
+			
+			iLength++;
+			if(val == 0)
+				{
+				iZeroCount++;
+				}
+			else
+				{
+				iSum += val;
+				}			
+			}		
+		}
+	
+	/**
+	 * ChecksumBlock - calculate checksum values for given data
+	 * @param aData - descriptor containing the data to checksum
+	 * @return void
+	 */
+	void TScmChecksum::ChecksumBlock(const TDesC8& aDes)
+		{
+		ChecksumBlock(aDes.Ptr(), aDes.Length());
+		}
+	
+	/**
+	 * ChecksumBlock - operator ==
+	 * @param aOther - the TScmChecksum to compare too
+	 * @return ETrue is objects match - otherwise EFalse
+	 */
+	TBool TScmChecksum::operator == (const TScmChecksum& aOther) const
+		{
+		return (iLength == aOther.iLength && iSum == aOther.iSum && iZeroCount == aOther.iZeroCount);
+		}
+
+	/**
+	 * ChecksumBlock - operator !=
+	 * @param aOther - the TScmChecksum to compare too
+	 * @return EFalse if objects match - otherwise ETrue
+	 */
+	TBool TScmChecksum::operator != (const TScmChecksum& aOther) const
+		{
+		return !(*this == aOther);
+		}
+	
+	/**
+	 * GetSize 
+	 * @return size of this object when streamed in bytes
+	 */
+	TInt TScmChecksum::GetSize() const
+ 		{
+ 		return 12;
+ 		}
+	
+	/**
+	 * Serialize - writes this object to the supplied byte stream
+	 * @param aItem -  aWriter - the TByteStreamWriter that will be written to
+	 * @return One of the OS wide codes
+	 */
+	TInt TScmChecksum::Serialize(TByteStreamWriter& aWriter)
+		{	
+		TInt startPos = aWriter.CurrentPosition();
+		aWriter.WriteInt(iLength);
+		aWriter.WriteInt(iSum);
+		aWriter.WriteInt(iZeroCount);
+		TInt sizeWritten = aWriter.CurrentPosition() - startPos;
+		if(sizeWritten != GetSize())
+			{
+			// error between actual size & real size in data
+			CLTRACE("TScmChecksum serialization size error");	
+			return KErrCorrupt;
+			}
+		return KErrNone;
+		}
+	
+
+	/**
+	 * Deserialize - read this objects state from the supplied byte stream
+	 * @param aItem -  aReader - the TByteStreamReader that will be read from
+	 * @return One of the OS wide codes
+	 */
+	TInt TScmChecksum::Deserialize(TByteStreamReader& aReader)
+		{
+		TInt startPos = aReader.CurrentPosition();
+		// do we need a version check here - will it change ?
+		iLength = aReader.ReadInt();	
+		iSum = aReader.ReadInt();
+		iZeroCount = aReader.ReadInt();	
+
+		TInt sizeRead = aReader.CurrentPosition() - startPos;
+		if(sizeRead != GetSize())
+			{
+			// error between actual size & real size in data
+			CLTRACE("TScmChecksum Deserialization size error");	
+			return KErrCorrupt;
+			}
+		return KErrCorrupt;
+		}
+	
+	
+	void TScmChecksum::Reset()
+		{
+		iLength = iSum = iZeroCount = 0;	
+		}		
+	}
+//eof
+