--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/secureswitools/swisistools/source/rscparser/dictionarycompression.cpp	Tue Aug 31 15:21:33 2010 +0300
@@ -0,0 +1,170 @@
+// Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of "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:
+// dictionarycompression.cpp
+//
+/** 
+* @file dictionarycompression.cpp
+*
+* @internalComponent
+* @released
+*/
+
+#include "dictionarycompression.h"
+
+RDictionaryCompressionBitStream::RDictionaryCompressionBitStream() :
+	iNumberOfBitsUsedForDictionaryTokens(0),
+	iOffsetToFirstBit(-1),
+	iOffsetToCurrentBit(-1),
+	iOffsetOnePastLastBit(-1),
+	iOwnsBitBuffer(false),
+	iBuffer(NULL)
+	{
+	}
+
+void RDictionaryCompressionBitStream::OpenL(
+				TInt aNumberOfBitsUsedForDictionaryTokens,
+				TInt aOffsetToFirstBit,
+				TInt aOffsetOnePastLastBit,
+				TBool aTransferringOwnershipOfBuffer,
+				TUint8* aBuffer)
+	{
+	iNumberOfBitsUsedForDictionaryTokens = aNumberOfBitsUsedForDictionaryTokens;
+	iOffsetToFirstBit = aOffsetToFirstBit;
+	iOffsetToCurrentBit = aOffsetToFirstBit;
+	iOffsetOnePastLastBit = aOffsetOnePastLastBit;
+	iOwnsBitBuffer = aTransferringOwnershipOfBuffer;
+	iBuffer = aBuffer;
+
+	assert(aBuffer!=NULL);
+	assert(aOffsetToFirstBit >= 0);
+	assert(aOffsetToFirstBit<=aOffsetOnePastLastBit);
+	}
+
+void RDictionaryCompressionBitStream::Close()
+	{
+	if (iOwnsBitBuffer)
+		{
+		iOwnsBitBuffer=EFalse;
+		delete [] iBuffer;
+		}
+	iBuffer=NULL;
+	}
+
+TBool RDictionaryCompressionBitStream::EndOfStreamL() const
+	{
+	assert(iBuffer!=NULL);
+	assert(iOffsetToFirstBit >= 0);
+	assert(iOffsetToCurrentBit>=iOffsetToFirstBit);
+	assert(iOffsetToCurrentBit<=iOffsetOnePastLastBit);
+	return iOffsetToCurrentBit>=iOffsetOnePastLastBit;
+	}
+
+TInt RDictionaryCompressionBitStream::IndexOfDictionaryEntryL()
+	{
+	// increments the current bit-position if it returns a value >=0; returns KErrNotFound if the next thing in the stream is plain data rather than the index of a dictionary entry
+	assert(iBuffer!=NULL);
+	assert(!EndOfStreamL());
+	if (!CurrentBitIsOn())
+		{
+		++iOffsetToCurrentBit;
+		return ReadIntegerL(iNumberOfBitsUsedForDictionaryTokens);
+		}
+	return KErrNotFound;
+	}
+
+void RDictionaryCompressionBitStream::ReadL(Ptr8 aBufferToAppendTo,TBool aCalypsoFileFormat)
+	{
+	// can only be called if IndexOfDictionaryEntry returned a negative value
+	assert(iBuffer!=NULL);
+	assert(!EndOfStreamL());
+	TInt numberOfConsecutivePrefixBits=0;
+	TInt i;
+	for (i=0; i<4; ++i)
+		{
+		const TBool currentBitIsOn=CurrentBitIsOn();
+		++iOffsetToCurrentBit; // increment this regardless whether the current bit is on
+		if (!currentBitIsOn)
+			{
+			break;
+			}
+		++numberOfConsecutivePrefixBits;
+		}
+	assert(numberOfConsecutivePrefixBits>0);
+	assert(numberOfConsecutivePrefixBits<=4);
+	TInt numberOfBytesToRead = numberOfConsecutivePrefixBits;
+	if (numberOfConsecutivePrefixBits==3)
+		{
+		numberOfBytesToRead=3+ReadIntegerL(3);
+		}
+	else if (numberOfConsecutivePrefixBits==4)
+		{
+		numberOfBytesToRead=ReadIntegerL(8);
+		if (!aCalypsoFileFormat)
+			{
+			numberOfBytesToRead+=3+(1<<3);
+			}
+		}
+
+	const TInt numberOfBitsOffByteBoundary=iOffsetToCurrentBit%8;
+	const TUint8* currentByte=iBuffer+(iOffsetToCurrentBit/8);
+	assert((numberOfBytesToRead + aBufferToAppendTo.GetLength()) <= aBufferToAppendTo.GetMaxLength());
+	for (i=0; i<numberOfBytesToRead; ++i, ++currentByte)
+		{
+		TUint byte=*currentByte;
+		assert(numberOfBitsOffByteBoundary>=0);
+		if (numberOfBitsOffByteBoundary>0)
+			{
+			byte>>=numberOfBitsOffByteBoundary;
+			byte|=(*(currentByte+1)<<(8-numberOfBitsOffByteBoundary));
+			byte&=0xff;
+			}
+		aBufferToAppendTo.Append(byte,1);
+		}
+	iOffsetToCurrentBit+=numberOfBytesToRead*8;
+	assert(numberOfBitsOffByteBoundary==iOffsetToCurrentBit%8);
+	}
+
+TBool RDictionaryCompressionBitStream::CurrentBitIsOn() const
+	{
+	// does not increment the current bit-position
+	assert(iBuffer!=NULL);
+	return iBuffer[iOffsetToCurrentBit/8]&(1<<(iOffsetToCurrentBit%8));
+	}
+
+TUint RDictionaryCompressionBitStream::ReadIntegerL(TInt aNumberOfBits)
+	{
+	// increments the current bit-position
+	assert(iBuffer!=NULL);
+	TInt integer=0;
+	TInt numberOfBitsLeftToRead=aNumberOfBits;
+//	FOREVER
+	while(1)
+		{
+		const TInt offsetToFirstBitToReadInCurrentByte=iOffsetToCurrentBit%8;
+		const TInt offsetOnePastLastBitToReadInCurrentByte=Min(8,offsetToFirstBitToReadInCurrentByte+numberOfBitsLeftToRead);
+		const TInt numberOfBitsReadFromCurrentByte=offsetOnePastLastBitToReadInCurrentByte-offsetToFirstBitToReadInCurrentByte;
+		assert(numberOfBitsReadFromCurrentByte>0);
+		const TUint bitsReadFromCurrentByte=((iBuffer[iOffsetToCurrentBit/8]>>offsetToFirstBitToReadInCurrentByte)&((1<<numberOfBitsReadFromCurrentByte)-1));
+		integer|=(bitsReadFromCurrentByte<<(aNumberOfBits-numberOfBitsLeftToRead));
+		iOffsetToCurrentBit+=numberOfBitsReadFromCurrentByte;
+		numberOfBitsLeftToRead-=numberOfBitsReadFromCurrentByte;
+		assert(numberOfBitsLeftToRead>=0);
+		if (numberOfBitsLeftToRead<=0)
+			{
+			break;
+			}
+		}
+	return integer;
+	}
+