secureswitools/swianalysistoolkit/source/common/ucmp.cpp
changeset 0 ba25891c3a9e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/secureswitools/swianalysistoolkit/source/common/ucmp.cpp	Thu Dec 17 08:51:10 2009 +0200
@@ -0,0 +1,763 @@
+/*
+* Copyright (c) 2006-2009 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: 
+* Ported from us_ucmp.cpp.
+* Implementation of the Standard Compression Scheme for Unicode.
+* This code is compiled only in the Unicode build. 
+*
+*/
+
+
+#include "ucmp.h"
+#include <stdexcept>
+
+namespace {
+const int KErrNotFound = -1;
+}
+
+const TUint32 TUnicodeCompressionState::iStaticWindow[EStaticWindows] =
+	{
+	0x0000,		// tags
+	0x0080,		// Latin-1 supplement
+	0x0100,		// Latin Extended-A
+	0x0300,		// Combining Diacritics
+	0x2000,		// General Punctuation
+	0x2080,		// Currency Symbols
+	0x2100,		// Letterlike Symbols and Number Forms
+	0x3000		// CJK Symbols and Punctuation
+	};
+
+const TUint32 TUnicodeCompressionState::iDynamicWindowDefault[EDynamicWindows] =
+	{
+	0x0080,		// Latin-1 supplement
+	0x00C0,		// parts of Latin-1 supplement and Latin Extended-A
+	0x0400,		// Cyrillic
+	0x0600,		// Arabic
+	0x0900,		// Devanagari
+	0x3040,		// Hiragana
+	0x30A0,		// Katakana
+	0xFF00		// Fullwidth ASCII
+	};
+
+const TUint16 TUnicodeCompressionState::iSpecialBase[ESpecialBases] =
+	{ 
+	0x00C0,		// Latin 1 letters (not symbols) and some of Extended-A
+	0x0250,		// IPA extensions
+	0x0370,		// Greek
+	0x0530,		// Armenian
+	0x3040,		// Hiragana
+	0x30A0,		// Katakana
+	0xFF60		// Halfwidth katakana
+	};
+
+// Single-byte mode tag values
+const TUint8 SQ0 = 0x01;	// <byte>				quote from window 0
+const TUint8 SDX = 0x0B;	// <hbyte> <lbyte>		define window in expansion area
+const TUint8 SQU = 0x0E;	// <hbyte> <lbyte>		quote Unicode value
+const TUint8 SCU = 0x0F;	//						switch to Unicode mode
+const TUint8 SC0 = 0x10;	//						select dynamic window 0
+const TUint8 SD0 = 0x18;	// <byte>				set dynamic window 0 index to <byte> and select it
+
+// Unicode mode tag values
+const TUint8 UC0 = 0xE0;	//						select dynamic window 0 and switch to single-byte mode
+const TUint8 UD0 = 0xE8;	// <byte>				set dynamic window 0 index to <byte>, select it and switch to
+							//						single-byte mode
+const TUint8 UQU = 0xF0;	// <hbyte>, <lbyte>		quote Unicode value
+const TUint8 UDX = 0xF1;	// <hbyte>, <lbyte>		define window in expansion area and switch to single-byte mode
+
+
+TUnicodeCompressionState::TUnicodeCompressionState():
+	iUnicodeWords(0),
+	iMaxUnicodeWords(0),
+	iCompressedBytes(0),
+	iMaxCompressedBytes(0)
+	{
+	Reset();
+	}
+
+void TUnicodeCompressionState::Reset()
+	{
+	iUnicodeMode = false;
+	iActiveWindowBase = 0x0080;
+	for (int i = 0; i < EDynamicWindows; i++)
+		iDynamicWindow[i] = iDynamicWindowDefault[i];
+	}
+
+
+// Return the index of the static window that contains this code, if any, or -1 if there is none.
+TInt32 TUnicodeCompressionState::StaticWindowIndex(TUint16 aCode)
+	{
+	for (TInt32 i = 0; i < EStaticWindows; i++)
+		if (aCode >= iStaticWindow[i] && aCode < iStaticWindow[i] + 128)
+			return i;
+	return -1;
+	}
+
+/*
+If aCode can be accommodated in one of the legal dynamic windows, return the index of that window
+in the offset table. If not return KErrNotFound.
+*/
+TInt32 TUnicodeCompressionState::DynamicWindowOffsetIndex(TUint16 aCode)
+	{
+	if (aCode < 0x0080)
+		return KErrNotFound;
+	if (aCode >= 0x3400 && aCode <= 0xDFFF)
+		return KErrNotFound;
+
+	/*
+	Prefer sections that cross half-->WriteUint8(block boundaries. These are better adapted to actual text.
+	They are represented by offset indices 0xf9..0xff.
+	*/
+	for (int i = 0; i < ESpecialBases; i++)
+		if (aCode >= iSpecialBase[i] && aCode < iSpecialBase[i] + 128)
+			return 0xF9 + i;
+
+	/*
+	Offset indices 0x01..0x67 represent half blocks from 0x0080 to 0x3380 and
+	0x68..0xA7 represent half blocks from 0xE000 to 0xFF80.
+	*/
+	if (aCode >= 0xE000)
+		aCode -= 0xAC00;
+	return aCode / 0x80;
+	}
+
+// Return the base of the window represented by offset index <n>. Return 0 if the offset index is illegal.
+TUint32 TUnicodeCompressionState::DynamicWindowBase(TInt32 aOffsetIndex)
+	{
+	if (aOffsetIndex >= 0xF9 && aOffsetIndex <= 0xFF)
+		{
+		/*->WriteUint8(
+		WARNING: don't optimise the following two lines by replacing them with
+		'return iSpecialBase[aOffsetIndex - 0xF9];'. To do so would re-introduce a problem
+		in ARM builds caused by optimisation and consequent erroneous fixing up
+		of the array base: see defect EDNGASR-4AGJQX in ER5U defects.
+		*/
+		int special_base_index = aOffsetIndex - 0xF9;
+		return iSpecialBase[special_base_index];
+		}
+	if (aOffsetIndex >= 0x01 && aOffsetIndex <= 0x67)
+		return aOffsetIndex * 0x80;
+	if (aOffsetIndex >= 0x68 && aOffsetIndex <= 0xA7)
+		return aOffsetIndex * 0x80 + 0xAC00;
+	return 0;
+	}
+
+TBool TUnicodeCompressionState::EncodeAsIs(TUint16 aCode)
+	{
+	return aCode == 0x0000 || aCode == 0x0009 || aCode == 0x000A || aCode == 0x000D ||
+		   (aCode >= 0x0020 && aCode <= 0x007F);
+	}
+
+void TUnicodeCompressionState::Panic(TPanic /*aPanic*/)
+	{
+	throw std::runtime_error("ucmp");
+	}
+
+ TUnicodeCompressor::TUnicodeCompressor():
+	iInputBufferStart(0),
+	iInputBufferSize(0),
+	iOutputBufferStart(0),
+	iOutputBufferSize(0),
+	iDynamicWindowIndex(0),
+	iOutputStream(NULL),
+	iOutputPointer(NULL),
+	iInput(NULL)
+	{
+	}
+
+ void TUnicodeCompressor::Compress(Serialiser& aOutput,MUnicodeSource& aInput,
+											TInt32 aMaxOutputBytes,TInt32 aMaxInputWords,
+											TInt32* aOutputBytes,TInt32* aInputWords)
+	{
+	DoCompress(&aOutput,NULL,&aInput,aMaxOutputBytes,aMaxInputWords,aOutputBytes,aInputWords);
+	}
+
+ void TUnicodeCompressor::Compress(TUint8* aOutput,MUnicodeSource& aInput,
+											TInt32 aMaxOutputBytes,TInt32 aMaxInputWords,
+											TInt32* aOutputBytes,TInt32* aInputWords)
+	{
+	DoCompress(NULL,aOutput,&aInput,aMaxOutputBytes,aMaxInputWords,aOutputBytes,aInputWords);
+	}
+
+ TInt32 TUnicodeCompressor::Flush(Serialiser& aOutput,TInt32 aMaxOutputBytes,TInt32& aOutputBytes)
+	{
+	DoCompress(&aOutput,NULL,NULL,aMaxOutputBytes,0,&aOutputBytes,NULL);
+	return iOutputBufferSize;
+	}
+
+ TInt32 TUnicodeCompressor::Flush(TUint8* aOutput,TInt32 aMaxOutputBytes,TInt32& aOutputBytes)
+	{
+	DoCompress(NULL,aOutput,NULL,aMaxOutputBytes,0,&aOutputBytes,NULL);
+	return iOutputBufferSize;
+	}
+
+ TInt32 TUnicodeCompressor::CompressedSize(MUnicodeSource& aInput,TInt32 aInputWords)
+	{
+	TInt32 bytes;
+	TUnicodeCompressor c;
+	c.DoCompress(NULL,NULL,&aInput,KMaxTInt,aInputWords,&bytes,NULL);
+	return bytes;
+	}
+
+// Compress until input or output is exhausted or an exception occurs.
+void TUnicodeCompressor::DoCompress(Serialiser* aOutputStream,TUint8* aOutputPointer,MUnicodeSource* aInput,
+									 TInt32 aMaxOutputBytes,TInt32 aMaxInputWords,
+									 TInt32* aOutputBytes,TInt32* aInputWords)
+	{
+	iOutputStream = aOutputStream;
+	iOutputPointer = aOutputPointer;
+	iInput = aInput;
+	iMaxCompressedBytes = aMaxOutputBytes;
+	iMaxUnicodeWords = aMaxInputWords;
+	iCompressedBytes = iUnicodeWords = 0;
+	FlushOutputBuffer();
+	if (iInput)
+		{
+		while (iUnicodeWords < iMaxUnicodeWords && iCompressedBytes < iMaxCompressedBytes)
+			{
+			TUint16 x = iInput->ReadUnicodeValue();
+			TAction action(x);
+			iInputBuffer[(iInputBufferStart + iInputBufferSize) % EMaxInputBufferSize] = action;
+			iInputBufferSize++;
+			iUnicodeWords++;
+			if (iInputBufferSize == EMaxInputBufferSize)
+				WriteRun();
+			}
+		}
+	FlushInputBuffer();
+	if (aOutputBytes)
+		*aOutputBytes = iCompressedBytes;
+	if (aInputWords)
+		*aInputWords = iUnicodeWords;
+	}
+
+TUnicodeCompressor::TAction::TAction(TUint16 aCode):
+	iCode(aCode)
+	{
+	if (TUnicodeCompressionState::EncodeAsIs(aCode))
+		iTreatment = EPlainASCII;
+	else
+		{
+		iTreatment = TUnicodeCompressionState::DynamicWindowOffsetIndex(aCode);
+		if (iTreatment == -1)
+			{
+			iTreatment = TUnicodeCompressionState::StaticWindowIndex(aCode);
+			if (iTreatment == -1)
+				iTreatment = EPlainUnicode;
+			else
+				iTreatment += EFirstStatic;
+			}
+		}
+	}
+
+void TUnicodeCompressor::WriteCharacterFromBuffer()
+	{
+	const TAction& action = iInputBuffer[iInputBufferStart];
+	iInputBufferSize--;
+	iInputBufferStart = (iInputBufferStart + 1) % EMaxInputBufferSize;
+	WriteCharacter(action);
+	}
+
+void TUnicodeCompressor::FlushInputBuffer()
+	{
+	while (iInputBufferSize > 0 && iCompressedBytes < iMaxCompressedBytes)
+		WriteRun();
+	}
+
+void TUnicodeCompressor::WriteRun()
+	{
+	// Write out any leading characters that can be passed through.
+	if (!iUnicodeMode)
+		while (iInputBufferSize > 0)
+			{
+			const TAction& action = iInputBuffer[iInputBufferStart];
+			if (action.iTreatment == TAction::EPlainASCII ||
+				(action.iCode >= iActiveWindowBase && action.iCode < iActiveWindowBase + 128))
+				WriteCharacterFromBuffer();
+			else
+				break;
+			}
+
+	// Write a run of characters that cannot be passed through.
+	int i;
+	if (iInputBufferSize > 0)
+		{
+		/*
+		Find a run of characters with the same treatment and select that treatment
+		if the run has more than one character.
+		*/
+		int treatment = iInputBuffer[iInputBufferStart].iTreatment;
+		int next_treatment = treatment;
+		int run_size = 1;
+		for (i = 1; i < iInputBufferSize; i++)
+			{
+			int index = (iInputBufferStart + i) % EMaxInputBufferSize;
+			next_treatment = iInputBuffer[index].iTreatment;
+			if (next_treatment != treatment)
+				break;
+			run_size++;
+			}
+		if (run_size > 1)
+			SelectTreatment(treatment);
+		for (i = 0; i < run_size; i++)
+			WriteCharacterFromBuffer();
+		}
+
+	FlushOutputBuffer();
+	}
+
+void TUnicodeCompressor::FlushOutputBuffer()
+	{
+	while (iOutputBufferSize > 0 &&	iCompressedBytes < iMaxCompressedBytes)
+		{
+		TUint8 byte = iOutputBuffer[iOutputBufferStart];
+		if (iOutputPointer)
+			*iOutputPointer++ = byte;
+		else if (iOutputStream)
+			*iOutputStream << byte;
+		iCompressedBytes++;
+		iOutputBufferSize--;
+		iOutputBufferStart = (iOutputBufferStart + 1) % EMaxOutputBufferSize;
+		}
+	}
+
+void TUnicodeCompressor::SelectTreatment(TInt32 aTreatment)
+	{
+	if (aTreatment == TAction::EPlainUnicode)
+		{
+		// Switch to Unicode mode if not there already.
+		if (!iUnicodeMode)
+			{
+			WriteByte(SCU);
+			iUnicodeMode = true;
+			}
+		return;
+		}
+
+	if (aTreatment == TAction::EPlainASCII)
+		{
+		// Switch to single-byte mode, using the current dynamic window, if not there already.
+		if (iUnicodeMode)
+			{
+			WriteByte(UC0 + iDynamicWindowIndex);
+			iUnicodeMode = false;
+			}
+		return;
+		}
+
+	if (aTreatment >= TAction::EFirstDynamic && aTreatment <= TAction::ELastDynamic)
+		{
+		TUint32 base = DynamicWindowBase(aTreatment);
+
+		// Switch to the appropriate dynamic window if it is available; if not, redefine and select dynamic window 4.
+		for (int i = 0; i < EDynamicWindows; i++)
+			if (base == iDynamicWindow[i])
+				{
+				if (iUnicodeMode)
+					WriteByte(UC0 + i);
+				else if (i != iDynamicWindowIndex)
+					WriteByte(SC0 + i);
+				iUnicodeMode = false;
+				iDynamicWindowIndex = i;
+				iActiveWindowBase = base;
+				return;
+				}
+		if (iUnicodeMode)
+			WriteByte(UD0 + 4);
+		else
+			WriteByte(SD0 + 4);
+		iDynamicWindowIndex = 4;
+		iUnicodeMode = false;
+		WriteByte(aTreatment);
+		iDynamicWindow[4] = base;
+		iActiveWindowBase = base;
+		return;
+		}
+	}
+
+// Write a character without changing mode or window.
+void TUnicodeCompressor::WriteCharacter(const TAction& aAction)
+	{
+	if (iUnicodeMode)
+		WriteUCharacter(aAction.iCode);
+	else
+		WriteSCharacter(aAction);
+	}
+
+void TUnicodeCompressor::WriteUCharacter(TUint16 aCode)
+	{
+	// Emit the 'quote Unicode' tag if the character would conflict with a tag.
+	if (aCode >= 0xE000 && aCode <= 0xF2FF)
+		WriteByte(UQU);
+
+	// Write the Unicode value big-end first.
+	WriteByte((aCode >> 8) & 0xFF);
+	WriteByte(aCode & 0xFF);
+	}
+
+void TUnicodeCompressor::WriteByte(TUint32 aByte)
+	{
+	if (iOutputBufferSize >= EMaxOutputBufferSize)
+		Panic(EOutputBufferOverflow);
+	iOutputBuffer[(iOutputBufferStart + iOutputBufferSize) % EMaxOutputBufferSize] = (TUint8)aByte;
+	iOutputBufferSize++;
+	}
+
+void TUnicodeCompressor::WriteSCharacter(const TAction& aAction)
+	{
+	// Characters in the range 0x0020..0x007F, plus nul, tab, cr, and lf, can be emitted as their low bytes.
+	if (aAction.iTreatment == TAction::EPlainASCII)
+		{
+		WriteByte(aAction.iCode);
+		return;
+		}
+
+	// Characters in a static window can be written using SQ<n> plus a byte in the range 0x00-0x7F
+	if (aAction.iTreatment >= TAction::EFirstStatic && aAction.iTreatment <= TAction::ELastStatic)
+		{
+		int window = aAction.iTreatment - TAction::EFirstStatic;
+		WriteByte(SQ0 + window);
+		WriteByte(aAction.iCode);
+		return;
+		}
+
+	// Characters in the current dynamic window can be written as a byte in the range 0x80-0xFF.
+	if (aAction.iCode >= iActiveWindowBase && aAction.iCode < iActiveWindowBase + 128)
+		{
+		WriteByte(aAction.iCode - iActiveWindowBase + 0x80);
+		return;
+		}
+
+	// Characters in another dynamic window can be written using SQ<n> plus a byte in the range 0x80-0xFF
+	int i;
+	for (i = 0; i < EDynamicWindows; i++)
+		if (aAction.iCode >= iDynamicWindow[i] && aAction.iCode < iDynamicWindow[i] + 128)
+			{
+			WriteByte(SQ0 + i);
+			WriteByte(aAction.iCode - iDynamicWindow[i] + 0x80);
+			return;
+			}
+
+	// Other characters can be quoted.
+	WriteByte(SQU);
+	WriteByte((aAction.iCode >> 8) & 0xFF);
+	WriteByte(aAction.iCode & 0xFF);
+	return;
+	}
+
+ TUnicodeExpander::TUnicodeExpander():
+	iInputBufferStart(0),
+	iInputBufferSize(0),
+	iOutputBufferStart(0),
+	iOutputBufferSize(0),
+	iOutput(NULL),
+	iInputStream(NULL),
+	iInputPointer(NULL)
+	{
+	}
+
+ void TUnicodeExpander::Expand(MUnicodeSink& aOutput,Deserialiser& aInput,
+										TInt32 aMaxOutputWords,TInt32 aMaxInputBytes,
+										TInt32* aOutputWords,TInt32* aInputBytes)
+	{
+	DoExpand(&aOutput,&aInput,NULL,aMaxOutputWords,aMaxInputBytes,aOutputWords,aInputBytes);
+	}
+
+ void TUnicodeExpander::Expand(MUnicodeSink& aOutput,const TUint8* aInput,
+										TInt32 aMaxOutputWords,TInt32 aMaxInputBytes,
+										TInt32* aOutputWords,TInt32* aInputBytes)
+	{
+	DoExpand(&aOutput,NULL,aInput,aMaxOutputWords,aMaxInputBytes,aOutputWords,aInputBytes);
+	}
+
+ TInt32 TUnicodeExpander::Flush(MUnicodeSink& aOutput,TInt32 aMaxOutputWords,TInt32& aOutputWords)
+	{
+	DoExpand(&aOutput,NULL,NULL,aMaxOutputWords,0,&aOutputWords,NULL);
+	return iOutputBufferSize;
+	}
+
+ TInt32 TUnicodeExpander::ExpandedSize(Deserialiser& aInput,TInt32 aInputBytes)
+	{
+	TInt32 words;
+	TUnicodeExpander e;
+	e.DoExpand(NULL,&aInput,NULL,KMaxTInt,aInputBytes,&words,NULL);
+	return words;
+	}
+
+ TInt32 TUnicodeExpander::ExpandedSize(const TUint8* aInput,TInt32 aInputBytes)
+	{
+	TInt32 words;
+	TUnicodeExpander e;
+	e.DoExpand(NULL,NULL,aInput,KMaxTInt,aInputBytes,&words,NULL);
+	return words;
+	}
+
+// Expand until input or output is exhausted or an exception occurs.
+void TUnicodeExpander::DoExpand(MUnicodeSink* aOutput,Deserialiser* aInputStream,const TUint8* aInputPointer,
+								 TInt32 aMaxOutputWords,TInt32 aMaxInputBytes,
+								 TInt32* aOutputWords,TInt32* aInputBytes)
+	{
+	iOutput = aOutput;
+	iInputStream = aInputStream;
+	iInputPointer = aInputPointer;
+	iMaxUnicodeWords = aMaxOutputWords;
+	iMaxCompressedBytes = aMaxInputBytes;
+	iUnicodeWords = iCompressedBytes = 0;
+	iInputBufferStart = 0;
+	FlushOutputBuffer();
+	if (iInputPointer || iInputStream)
+		{
+		while (iUnicodeWords + iOutputBufferSize < iMaxUnicodeWords && iCompressedBytes < iMaxCompressedBytes)
+			HandleByte();
+		}
+	if (aOutputWords)
+		*aOutputWords = iUnicodeWords;
+	if (aInputBytes)
+		*aInputBytes = iCompressedBytes;
+	}
+
+void TUnicodeExpander::HandleByte()
+	{
+	TUint8 byte;
+	TBool handled = false;
+	if (ReadByte(byte))
+		{
+		if (iUnicodeMode)
+			handled = HandleUByte(byte);
+		else
+			handled = HandleSByte(byte);
+		}
+	iInputBufferStart = 0;
+	if (handled)
+		iInputBufferSize = 0;
+	FlushOutputBuffer();
+	}
+
+void TUnicodeExpander::FlushOutputBuffer()
+	{
+	while (iOutputBufferSize > 0 &&	iUnicodeWords < iMaxUnicodeWords)
+		{
+		if (iOutput)
+			iOutput->WriteUnicodeValue(iOutputBuffer[iOutputBufferStart]);
+		iUnicodeWords++;
+		iOutputBufferSize--;
+		iOutputBufferStart = (iOutputBufferStart + 1) % EMaxOutputBufferSize;
+		}
+	}
+
+TBool TUnicodeExpander::HandleSByte(TUint8 aByte)
+	{
+	// 'Pass-through' codes.
+	if (TUnicodeCompressionState::EncodeAsIs(aByte))
+		{
+		WriteChar(aByte);
+		return true;
+		}
+
+	// Codes 0x80-0xFF select a character from the active window.
+	if (aByte >= 0x80)
+		{
+		WriteChar32(iActiveWindowBase + aByte - 0x80);
+		return true;
+		}
+
+	// SQU: quote a Unicode character.
+	if (aByte == SQU)
+		return QuoteUnicode();
+
+	// SCU: switch to Unicode mode.
+	if (aByte == SCU)
+		{
+		iUnicodeMode = true;
+		return true;
+		}
+
+	// SQn: quote from window n.
+	if (aByte >= SQ0 && aByte <= SQ0 + 7)
+		{
+		int window = aByte - SQ0;
+		TUint8 byte;
+		if (ReadByte(byte))
+			{
+			TUint32 c = byte;
+			if (c <= 0x7F)
+				c += iStaticWindow[window];
+			else
+				c += iDynamicWindow[window] - 0x80;
+			WriteChar32(c);
+			return true;
+			}
+		else
+			return false;
+		}
+
+	// SCn: switch to dynamic window n.
+	if (aByte >= SC0 && aByte <= SC0 + 7)
+		{
+		iActiveWindowBase = iDynamicWindow[aByte - SC0];
+		return true;
+		}
+
+	// SDn: define dynamic window n and switch to it.
+	if (aByte >= SD0 && aByte <= SD0 + 7)
+		return DefineWindow(aByte - SD0);
+
+	// SDX: define window in the expansion space.
+	if (aByte == SDX)
+		return DefineExpansionWindow();
+
+	Panic(EUnhandledByte);
+	return false;
+	}
+
+TBool TUnicodeExpander::HandleUByte(TUint8 aByte)
+	{
+	// Plain Unicode; get the low byte and emit the Unicode value.
+	if (aByte <= 0xDF || aByte >= 0xF3)
+		{
+		TUint8 lo;
+		if (ReadByte(lo))
+			{
+			TUint16 c = (TUint16)((aByte << 8) | lo);
+			WriteChar(c);
+			return true;
+			}
+		else
+			return false;
+		}
+
+	// Quote a Unicode character that would otherwise conflict with a tag.
+	if (aByte == UQU)
+		return QuoteUnicode();
+
+	// UCn: change to single byte mode and select window n.
+	if (aByte >= UC0 && aByte <= UC0 + 7)
+		{
+		iUnicodeMode = false;
+		iActiveWindowBase = iDynamicWindow[aByte - UC0];
+		return true;
+		}
+
+	// UDn: define dynamic window n and switch to it.
+	if (aByte >= UD0 && aByte <= UD0 + 7)
+		return DefineWindow(aByte - UD0);
+
+	// UDX: define window in the expansion space.
+	if (aByte == UDX)
+		return DefineExpansionWindow();
+
+	Panic(EUnhandledByte);
+	return false;
+	}
+
+TBool TUnicodeExpander::QuoteUnicode()
+	{
+	TUint8 hi, lo;
+	if (ReadByte(hi) && ReadByte(lo))
+		{
+		TUint16 c = (TUint16)((hi << 8) | lo);
+		WriteChar(c);
+		return true;
+		}
+	else
+		return false;
+	}
+
+TBool TUnicodeExpander::DefineWindow(TInt32 aIndex)
+	{
+	TUint8 window;
+	if (ReadByte(window))
+		{
+		iUnicodeMode = false;
+		iActiveWindowBase = DynamicWindowBase(window);
+		iDynamicWindow[aIndex] = iActiveWindowBase;
+		return true;
+		}
+	else
+		return false;
+	}
+
+TBool TUnicodeExpander::DefineExpansionWindow()
+	{
+	TUint8 hi, lo;
+	if (ReadByte(hi) && ReadByte(lo))
+		{
+		iUnicodeMode = false;
+		iActiveWindowBase = 0x10000 + (0x80 * ((hi & 0x1F) * 0x100 + lo));
+		iDynamicWindow[hi >> 5] = iActiveWindowBase;
+		return true;
+		}
+	else
+		return false;
+	}
+
+// Read either from the buffer (in the case of restarting after source finished in mid-operation) or from the source.
+TBool TUnicodeExpander::ReadByte(TUint8& aByte)
+	{
+	if (iInputBufferStart < iInputBufferSize)
+		{
+		aByte = iInputBuffer[iInputBufferStart++];
+		return true;
+		}
+	else if (iCompressedBytes < iMaxCompressedBytes)
+		{
+		if (iInputPointer)
+			aByte = *iInputPointer++;
+		else
+			*iInputStream >> aByte;
+		iInputBuffer[iInputBufferStart++] = aByte;
+		iInputBufferSize = iInputBufferStart;
+		iCompressedBytes++;
+		return true;
+		}
+	else
+		return false;
+	}
+
+void TUnicodeExpander::WriteChar(TUint16 aChar)
+	{
+	if (iOutputBufferSize >= EMaxOutputBufferSize)
+		Panic(EOutputBufferOverflow);
+	iOutputBuffer[(iOutputBufferStart + iOutputBufferSize) % EMaxOutputBufferSize] = aChar;
+	iOutputBufferSize++;
+	}
+
+// Write a Unicode character; write using surrogates if in the range 0x10000..0x10FFFF.
+void TUnicodeExpander::WriteChar32(TUint32 aChar)
+	{
+	if (aChar <= 0xFFFF)
+		WriteChar((TUint16)aChar);
+	else if (aChar <= 0x10FFFF)
+		{
+		aChar -= 0x10000;									// reduce to 20-bit value in the range 0x0..0xFFFFF
+		WriteChar((TUint16)(0xD800 + (aChar >> 10)));		// first high surrogate + high 10 bits
+		WriteChar((TUint16)(0xDC00 + (aChar & 0x03FF)));	// first low surrogate + low 10 bits
+		}
+	else
+		Panic(ENotUnicode);
+	}
+
+
+void TMemoryStreamUnicodeSink::WriteUnicodeValue(TUint16 aValue)
+	{
+	iStream.write((const char*)&aValue,sizeof(TUint16));
+	}
+
+TUint16 TMemoryStreamUnicodeSource::ReadUnicodeValue()
+	{
+	TUint16 x;
+	iStream.read((char *)&x,sizeof(TUint16));
+	return x;
+	}
+