sl@0: /*
sl@0: * Copyright (c) 2003-2010 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description:
sl@0: * Definitions for bidirectional text reordering.
sl@0: * 
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: 
sl@0: #ifndef BIDI_H_
sl@0: #define BIDI_H_
sl@0: 
sl@0: #include <e32std.h>
sl@0: 
sl@0: class RWriteStream;
sl@0: class RReadStream;
sl@0: 
sl@0: 
sl@0: class TBidirectionalState
sl@0: /** 
sl@0: The bidirectional state class. 
sl@0: This class contains functions that implement the Unicode Bidirectional Algorithm, 
sl@0: which changes text from logical order to display order for the correct display 
sl@0: of right-to-left scripts, like Arabic and Hebrew. A TBidirectionalState object 
sl@0: carries the embedding level and stack from one line to the next. On construction 
sl@0: it is in its 'start of paragraph' state. 
sl@0: @publishedAll
sl@0: @released
sl@0: */
sl@0: 	{
sl@0: 	friend class CTBiDi;
sl@0: 	
sl@0: public:
sl@0: 	
sl@0: 	class TRunInfo
sl@0: 	/** 
sl@0: 	Information about a run of characters with the same bidirectional 
sl@0: 	category. 
sl@0: 
sl@0: 	An array of these representing a line is passed into, and reordered by, 
sl@0: 	ReorderLine(). 
sl@0: 	@publishedAll
sl@0: 	@released
sl@0: 	*/
sl@0: 		{
sl@0: 		public:
sl@0: 		/** Category of a run of text: passed to ReorderLine(); these are 
sl@0: 		passed in as TChar::TBdCategory values but are modified for internal 
sl@0: 		use. */
sl@0: 		TUint iCategory;		
sl@0: 		/** Embedding level of this run: used internally by ReorderLine(). */
sl@0: 		TUint8 iEmbeddingLevel;	
sl@0: 		/** Resolved direction of this run: 0 for left to right, 1 for right 
sl@0: 		to left. */
sl@0: 		TUint8 iDirection;		
sl@0: 		/** Index of this run after reordering. */
sl@0: 		TInt iIndex;			
sl@0: 		/** Start of text; returned by ReorderText(). */
sl@0: 		TInt iStart;			
sl@0: 		/** Length of text; returned by ReorderText(). */
sl@0: 		TInt iLength;			
sl@0: 		};
sl@0: 
sl@0: 	IMPORT_C TBidirectionalState();
sl@0: 	IMPORT_C void ReorderLine(TRunInfo* aRunInfo,TInt aRuns,TBool aParStart,TBool aParEnd,TBool aParRightToLeft,
sl@0: 					 TChar::TBdCategory aNextCategory,TChar::TBdCategory aNextStrongCategory,
sl@0: 					 TBool& aVisualEndIsAmbiguous);
sl@0: 	IMPORT_C void ReorderLine(TRunInfo* aRunInfo,TInt aRuns,TBool aParStart,TBool aParEnd,TBool aParRightToLeft,
sl@0: 					 TChar::TBdCategory aNextCategory,TChar::TBdCategory aNextStrongCategory);
sl@0: 	IMPORT_C static TInt ReorderText(const TText* aText,TInt aLength,TBool aParRightToLeft,TText*& aNewText);
sl@0: 	IMPORT_C static void ReverseGroups(TText* aStart,TInt aLength);
sl@0: 	IMPORT_C void Reset();
sl@0: 	IMPORT_C TBool IsDefault() const;
sl@0: 	IMPORT_C TBool operator==(const TBidirectionalState& aState) const;
sl@0: 	IMPORT_C void ExternalizeL(RWriteStream& aDest);
sl@0: 	IMPORT_C void InternalizeL(RReadStream& aSource);
sl@0: 	TBool ParRightToLeft() const { return iStack[0].iEmbeddingLevel & 1; }
sl@0: 
sl@0: private:
sl@0: 	// Bidirectional categories coded as bit flags
sl@0: 	enum TCategory
sl@0: 		{
sl@0: 		ELeftToRight = 1 << TChar::ELeftToRight, 
sl@0: 		ELeftToRightEmbedding = 1 << TChar::ELeftToRightEmbedding,
sl@0: 		ELeftToRightOverride = 1 << TChar::ELeftToRightOverride,
sl@0: 		ERightToLeft = 1 << TChar::ERightToLeft,
sl@0: 		ERightToLeftArabic = 1 << TChar::ERightToLeftArabic,
sl@0: 		ERightToLeftEmbedding = 1 << TChar::ERightToLeftEmbedding, 
sl@0: 		ERightToLeftOverride = 1 << TChar::ERightToLeftOverride,
sl@0: 		EPopDirectionalFormat = 1 << TChar::EPopDirectionalFormat, 
sl@0: 		EEuropeanNumber = 1 << TChar::EEuropeanNumber, 
sl@0: 		EEuropeanNumberSeparator = 1 << TChar::EEuropeanNumberSeparator, 
sl@0: 		EEuropeanNumberTerminator = 1 << TChar::EEuropeanNumberTerminator, 
sl@0: 		EArabicNumber = 1 << TChar::EArabicNumber,
sl@0: 		ECommonNumberSeparator = 1 << TChar::ECommonNumberSeparator, 
sl@0: 		ENonSpacingMark = 1 << TChar::ENonSpacingMark, 
sl@0: 		EBoundaryNeutral = 1 << TChar::EBoundaryNeutral, 
sl@0: 		EParagraphSeparator = 1 << TChar::EParagraphSeparator, 
sl@0: 		ESegmentSeparator = 1 << TChar::ESegmentSeparator, 
sl@0: 		EWhitespace = 1 << TChar::EWhitespace, 
sl@0: 		EOtherNeutral = 1 << TChar::EOtherNeutral,
sl@0: 
sl@0: 		// useful groups
sl@0: 		EBdControlsGroup = ELeftToRightEmbedding | ERightToLeftEmbedding |
sl@0: 						   ELeftToRightOverride | ERightToLeftOverride | EPopDirectionalFormat,
sl@0: 		ELeftToRightGroup = ELeftToRight | EEuropeanNumber | ELeftToRightOverride | ELeftToRightEmbedding,
sl@0: 		ERightToLeftGroup = ERightToLeft | EArabicNumber | ERightToLeftArabic | ERightToLeftOverride |
sl@0: 							ERightToLeftEmbedding,
sl@0: 		EStrongGroup = ELeftToRightEmbedding | ERightToLeftEmbedding
sl@0: 			| ELeftToRightOverride | ERightToLeftOverride
sl@0: 			| ELeftToRight | ERightToLeft | ERightToLeftArabic,
sl@0: 
sl@0: 		ENoCategory = 0
sl@0: 		};
sl@0: 
sl@0: 	enum
sl@0: 		{
sl@0: 		EMaxExplicitLevel = 61,
sl@0: 		EMaxLevel = 63,
sl@0: 		EMaxStackLevels = 62
sl@0: 		};
sl@0: 
sl@0: 	enum TOverrideState
sl@0: 		{
sl@0: 		ENoOverrideState = 0,
sl@0: 		ELeftToRightOverrideState = ELeftToRightOverride,
sl@0: 		ERightToLeftOverrideState = ERightToLeftOverride
sl@0: 		};
sl@0: 
sl@0: 	class TStackItem
sl@0: 		{
sl@0: 	public:
sl@0: 		TUint8 iEmbeddingLevel;			// embedding level
sl@0: 		TOverrideState iOverrideState;	// directional override state
sl@0: 		TCategory iStartCategory;		// category that started this level; EOtherNeutral if none
sl@0: 		};
sl@0: 
sl@0: private:
sl@0: 	/**	The information needed during line reordering.
sl@0: 	WARNING: Class for internal use ONLY.  Compatibility is not guaranteed in future releases.	
sl@0: 	 */
sl@0: 	class TReorderContext
sl@0: 		{
sl@0: 	public:
sl@0: 		void SetNextCategory(TChar::TBdCategory aCat);
sl@0: 		void SetNextStrongCategory(TChar::TBdCategory aCat);
sl@0: 	public:
sl@0: 		/** Category at start of next line, or ON if at the end of the
sl@0: 		paragraph. */
sl@0: 		TCategory iNextCategory;
sl@0: 		/** Which of L, R or AL appears first in the remainder of the
sl@0: 		paragraph, or ON if none. */
sl@0: 		TCategory iNextStrongCategory;
sl@0: 		/** The run array for this line. */
sl@0: 		TRunInfo* iRunInfo;
sl@0: 		/** The length of iRunInfo. */
sl@0: 		TInt iRuns;
sl@0: 		/** Bitmap of categories currently present in iRunInfo. */
sl@0: 		TUint32 iCategories;
sl@0: 		/** Found by the algorithm to set iPreviousStrongCategory. */
sl@0: 		TCategory iLastStrongCategory;
sl@0: 		};
sl@0: 
sl@0: public:
sl@0: 	static TInt GenerateBdRunArray(const TText* aText, TInt aLength,
sl@0: 		TBidirectionalState::TRunInfo* aRun, TInt aMaxRuns);
sl@0: 
sl@0: private:
sl@0: 	const TStackItem& State() const { return iStack[iStackLevel]; }
sl@0: 	TCategory Push(TCategory aStartCategory);
sl@0: 	TCategory Pop();
sl@0: 
sl@0: public:
sl@0: 	TBidirectionalState(TChar::TBdCategory aPrevCat,
sl@0: 		TChar::TBdCategory aPrevStrongCat, TBool aParRightToLeft);
sl@0: 	void HandleBdControls(TReorderContext& aContext); 
sl@0: 	void ResolveWeakTypesW1W2W3(TReorderContext& aContext);
sl@0: 	void ResolveWeakTypesW4W5W6(TReorderContext& aContext); 
sl@0: 	void ResolveWeakTypesW7(TReorderContext& aContext); 
sl@0: 	void ResolveNeutralTypes(TReorderContext& aContext); 
sl@0: 	void ResolveImplicitLevels(TReorderContext& aContext); 
sl@0: 	void PrepareForNextLine(const TReorderContext& aContext);
sl@0: 	void ReorderRuns(TReorderContext& aContext);
sl@0: 	static TInt CatToNumber(TInt aCat);
sl@0: 	static TCategory CharToBdCat(TChar::TBdCategory aCat);
sl@0: 	static TCategory UintToBdCat(TUint aCat);
sl@0: 	static void DeneutralizeRuns(TRunInfo* aStart, TRunInfo* aEnd,
sl@0: 		TCategory aStartCategory, TCategory aEndCategory);
sl@0: private:
sl@0: 	TCategory iPreviousCategory;			// category at end of last line, or EStartOfParagraph if at start of par
sl@0: 	TCategory iPreviousStrongCategory;		// L or R; derived from embedding level if at start of par
sl@0: 	TInt16 iStackLevel;						// current stack level
sl@0: 	TInt8 iPushesBeyond60;	// number of times Push called with iStackLevel == 60 and Left-To-Right category
sl@0: 	TInt8 iPushesBeyond61;	// number of times Push called with iStackLevel == 61
sl@0: 	TStackItem iStack[EMaxStackLevels];		// the stack of embedding levels
sl@0: 	};
sl@0: 
sl@0: #endif // BIDI_H_