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/*------------------------------------------------------------------------
Copyright (C) 2002-2016 SIL International. All rights reserved.

Distributable under the terms of either the Common Public License or the
GNU Lesser General Public License, as specified in the LICENSING.txt file.

File: Engine.h
Responsibility: Jonathan Kew
Last reviewed: Not yet.

Description:
	internal header for the TECkit mapping engine
-------------------------------------------------------------------------*/

/*
	2004-03-19	jk	updated for version 2.2 with new match() function
	2003-09-23	jk	updated for version 2.1 with new Opt APIs
*/

#ifndef __Engine_H__
#define __Engine_H__

#include "TECkit_Engine.h"
#include "TECkit_Format.h"

const UInt32			kNeedMoreInput	= 0xfffffffeUL;
const UInt32			kInvalidChar	= 0xfffffffdUL;
const UInt32			kUnmappedChar	= 0xfffffffcUL;

class Converter;

class Stage
	/* abstract base class for pipeline stages, both mapping and normalization passes */
{
public:
						Stage();
	virtual				~Stage();
	
	virtual UInt32		getChar() = 0;
	
	virtual void		Reset() = 0;
	
	virtual UInt32		lookaheadCount() const;

protected:
	friend class Converter;

	UInt32*				oBuffer;
	long				oBufSize;
	long				oBufEnd;	// points to next unused slot in oBuffer
	long				oBufPtr;	// points to next char to be returned to caller (if less than oBufEnd)

	Stage*				prevStage;
};

class Normalizer
	: public Stage
{
public:
						Normalizer(bool compose);
	virtual				~Normalizer();

	virtual UInt32		getChar();

	virtual void		Reset();

protected:	
	UInt32				process();
	
	void				decompose(UInt32 c);
	UInt32				decomposeOne(UInt32& c);
	
	void				compose();
	void				generateChar(UInt32 c);
	void				appendChar(UInt32 c);
	void				insertChar(UInt32 insCh, int insCombClass);
	void				growOutBuf();

	int					prevCombClass;
	long				oBufSafe;
	
	bool				bCompose;
};

class Pass
	: public Stage
{
public:
						Pass(const TableHeader* inTable, Converter* cnv);
	virtual				~Pass();
	
	virtual UInt32		getChar();

	virtual void		Reset();

	virtual UInt32		lookaheadCount() const;

protected:
	UInt32				DoMapping();

	void				outputChar(UInt32 c);

	UInt32				inputChar(long inIndex);
	void				advanceInput(unsigned int numChars);

	long				classMatch(UInt32 classNumber, UInt32 inChar) const;
	UInt32				repClassMember(UInt32 classNumber, UInt32 index) const;

	struct MatchInfo {
		UInt32			classIndex;
		int				groupRepeats;
		struct {
			UInt16			start;
			UInt16			limit;
		}				matchedSpan;
	};

	UInt32				match(int index, int repeats, int textLoc);
								// returns 0 for no match, 1 for match, or kNeedMoreInput/kInvalidChar
	MatchElem*			pattern;
	int					patternLength;
	int					direction;
	MatchInfo			info[256];
	int					infoLimit;
	int					matchElems;
	int					matchedLength;

	int					groupRepeats;
	struct sgrStackItem {
		sgrStackItem*	link;
		int				savedGroupRepeats;
	};
	sgrStackItem*		sgrStack;

	Converter*			converter;
	const TableHeader*	tableHeader;

	const Byte*			pageBase;
	const Lookup*		lookupBase;
	const Byte*			matchClassBase;
	const Byte*			repClassBase;
	const Byte*			stringListBase;
	const Byte*			stringRuleData;
	const Byte*			planeMap;

	UInt32*				iBuffer;
	long				iBufSize;
	long				iBufStart;	// points to earliest valid char in iBuffer
	long				iBufEnd;	// points to next unused slot in iBuffer (one past last valid char)
	long				iBufPtr;	// points to next char to be fetched from iBuffer (if less than iBufEnd)

	bool				bInputIsUnicode;
	bool				bOutputIsUnicode;
	bool				bSupplementaryChars;
	UInt8				numPageMaps;
};

class Converter
	: public Stage
{
public:
						Converter(const Byte* inTable, UInt32 inTableSize, bool inForward,
									UInt16 inForm, UInt16 outForm);
						~Converter();

	TECkit_Status		ConvertBufferOpt(const Byte* inBuffer, UInt32 inLength, UInt32* inUsed,
							  Byte* outBuffer, UInt32 outLength, UInt32* outUsed,
							  UInt32 inOptions, UInt32* lookaheadCount);

	virtual void		Reset();

	virtual UInt32		getChar();

	bool				IsForward() const;
	void				GetFlags(UInt32& sourceFlags, UInt32& targetFlags) const;
	bool				GetNamePtr(UInt16 inNameID, const Byte*& outNamePtr, UInt32& outNameLen) const;

	class Exception
	{
	public:
						Exception(UInt32 errCode)
							: errorCode(errCode)
							{ }
		UInt32			errorCode;
	};

	long				creationStatus() const
							{ return status; }

	static bool			Validate(const Converter* cnv);

protected:
	friend class Pass;
	friend class Normalizer;

	UInt32				_getCharFn();
	UInt32				_getCharWithSavedBytes();
	void				_savePendingBytes();

	Byte*				table;
	
	Stage*				finalStage;
	
	const Byte*			data;
	UInt32				dataPtr;
	UInt32				dataLen;
	bool				inputComplete;
	Byte				unmappedBehavior;

	bool				forward;

	Byte				inputForm;
	Byte				outputForm;

	Byte				savedBytes[8];
	UInt32				savedCount;

	UInt32				pendingOutputChar;
	long				status;
	
	UInt32				warningStatus;
};

#endif /* __Engine_H__ */