williamr@2: /*
williamr@2: * Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).
williamr@2: * All rights reserved.
williamr@2: * This component and the accompanying materials are made available
williamr@2: * under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members
williamr@2: * which accompanies this distribution, and is available
williamr@2: * at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".
williamr@2: *
williamr@2: * Initial Contributors:
williamr@2: * Nokia Corporation - initial contribution.
williamr@2: *
williamr@2: * Contributors:
williamr@2: *
williamr@2: * Description:
williamr@2: * Definitions for bidirectional text reordering.
williamr@2: * 
williamr@2: *
williamr@2: */
williamr@2: 
williamr@2: 
williamr@2: 
williamr@2: 
williamr@2: 
williamr@2: 
williamr@2: #ifndef BIDI_H_
williamr@2: #define BIDI_H_
williamr@2: 
williamr@2: #include <e32std.h>
williamr@2: 
williamr@2: class RWriteStream;
williamr@2: class RReadStream;
williamr@2: 
williamr@2: 
williamr@2: class TBidirectionalState
williamr@2: /** 
williamr@2: The bidirectional state class. 
williamr@2: This class contains functions that implement the Unicode Bidirectional Algorithm, 
williamr@2: which changes text from logical order to display order for the correct display 
williamr@2: of right-to-left scripts, like Arabic and Hebrew. A TBidirectionalState object 
williamr@2: carries the embedding level and stack from one line to the next. On construction 
williamr@2: it is in its 'start of paragraph' state. 
williamr@2: @publishedAll
williamr@2: @released
williamr@2: */
williamr@2: 	{
williamr@2: public:
williamr@2: 	
williamr@2: 	class TRunInfo
williamr@2: 	/** 
williamr@2: 	Information about a run of characters with the same bidirectional 
williamr@2: 	category. 
williamr@2: 
williamr@2: 	An array of these representing a line is passed into, and reordered by, 
williamr@2: 	ReorderLine(). 
williamr@2: 	@publishedAll
williamr@2: 	@released
williamr@2: 	*/
williamr@2: 		{
williamr@2: 		public:
williamr@2: 		/** Category of a run of text: passed to ReorderLine(); these are 
williamr@2: 		passed in as TChar::TBdCategory values but are modified for internal 
williamr@2: 		use. */
williamr@2: 		TUint iCategory;		
williamr@2: 		/** Embedding level of this run: used internally by ReorderLine(). */
williamr@2: 		TUint8 iEmbeddingLevel;	
williamr@2: 		/** Resolved direction of this run: 0 for left to right, 1 for right 
williamr@2: 		to left. */
williamr@2: 		TUint8 iDirection;		
williamr@2: 		/** Index of this run after reordering. */
williamr@2: 		TInt iIndex;			
williamr@2: 		/** Start of text; returned by ReorderText(). */
williamr@2: 		TInt iStart;			
williamr@2: 		/** Length of text; returned by ReorderText(). */
williamr@2: 		TInt iLength;			
williamr@2: 		};
williamr@2: 
williamr@2: 	IMPORT_C TBidirectionalState();
williamr@2: 	IMPORT_C void ReorderLine(TRunInfo* aRunInfo,TInt aRuns,TBool aParStart,TBool aParEnd,TBool aParRightToLeft,
williamr@2: 					 TChar::TBdCategory aNextCategory,TChar::TBdCategory aNextStrongCategory,
williamr@2: 					 TBool& aVisualEndIsAmbiguous);
williamr@2: 	IMPORT_C void ReorderLine(TRunInfo* aRunInfo,TInt aRuns,TBool aParStart,TBool aParEnd,TBool aParRightToLeft,
williamr@2: 					 TChar::TBdCategory aNextCategory,TChar::TBdCategory aNextStrongCategory);
williamr@2: 	IMPORT_C static TInt ReorderText(const TText* aText,TInt aLength,TBool aParRightToLeft,TText*& aNewText);
williamr@2: 	IMPORT_C static void ReverseGroups(TText* aStart,TInt aLength);
williamr@2: 	IMPORT_C void Reset();
williamr@2: 	IMPORT_C TBool IsDefault() const;
williamr@2: 	IMPORT_C TBool operator==(const TBidirectionalState& aState) const;
williamr@2: 	IMPORT_C void ExternalizeL(RWriteStream& aDest);
williamr@2: 	IMPORT_C void InternalizeL(RReadStream& aSource);
williamr@2: 	TBool ParRightToLeft() const { return iStack[0].iEmbeddingLevel & 1; }
williamr@2: 
williamr@2: private:
williamr@2: 	// Bidirectional categories coded as bit flags
williamr@2: 	enum TCategory
williamr@2: 		{
williamr@2: 		ELeftToRight = 1 << TChar::ELeftToRight, 
williamr@2: 		ELeftToRightEmbedding = 1 << TChar::ELeftToRightEmbedding,
williamr@2: 		ELeftToRightOverride = 1 << TChar::ELeftToRightOverride,
williamr@2: 		ERightToLeft = 1 << TChar::ERightToLeft,
williamr@2: 		ERightToLeftArabic = 1 << TChar::ERightToLeftArabic,
williamr@2: 		ERightToLeftEmbedding = 1 << TChar::ERightToLeftEmbedding, 
williamr@2: 		ERightToLeftOverride = 1 << TChar::ERightToLeftOverride,
williamr@2: 		EPopDirectionalFormat = 1 << TChar::EPopDirectionalFormat, 
williamr@2: 		EEuropeanNumber = 1 << TChar::EEuropeanNumber, 
williamr@2: 		EEuropeanNumberSeparator = 1 << TChar::EEuropeanNumberSeparator, 
williamr@2: 		EEuropeanNumberTerminator = 1 << TChar::EEuropeanNumberTerminator, 
williamr@2: 		EArabicNumber = 1 << TChar::EArabicNumber,
williamr@2: 		ECommonNumberSeparator = 1 << TChar::ECommonNumberSeparator, 
williamr@2: 		ENonSpacingMark = 1 << TChar::ENonSpacingMark, 
williamr@2: 		EBoundaryNeutral = 1 << TChar::EBoundaryNeutral, 
williamr@2: 		EParagraphSeparator = 1 << TChar::EParagraphSeparator, 
williamr@2: 		ESegmentSeparator = 1 << TChar::ESegmentSeparator, 
williamr@2: 		EWhitespace = 1 << TChar::EWhitespace, 
williamr@2: 		EOtherNeutral = 1 << TChar::EOtherNeutral,
williamr@2: 
williamr@2: 		// useful groups
williamr@2: 		EBdControlsGroup = ELeftToRightEmbedding | ERightToLeftEmbedding |
williamr@2: 						   ELeftToRightOverride | ERightToLeftOverride | EPopDirectionalFormat,
williamr@2: 		ELeftToRightGroup = ELeftToRight | EEuropeanNumber | ELeftToRightOverride | ELeftToRightEmbedding,
williamr@2: 		ERightToLeftGroup = ERightToLeft | EArabicNumber | ERightToLeftArabic | ERightToLeftOverride |
williamr@2: 							ERightToLeftEmbedding,
williamr@2: 		EStrongGroup = ELeftToRightEmbedding | ERightToLeftEmbedding
williamr@2: 			| ELeftToRightOverride | ERightToLeftOverride
williamr@2: 			| ELeftToRight | ERightToLeft | ERightToLeftArabic,
williamr@2: 
williamr@2: 		ENoCategory = 0
williamr@2: 		};
williamr@2: 
williamr@2: 	enum
williamr@2: 		{
williamr@2: 		EMaxExplicitLevel = 61,
williamr@2: 		EMaxLevel = 63,
williamr@2: 		EMaxStackLevels = 62
williamr@2: 		};
williamr@2: 
williamr@2: 	enum TOverrideState
williamr@2: 		{
williamr@2: 		ENoOverrideState = 0,
williamr@2: 		ELeftToRightOverrideState = ELeftToRightOverride,
williamr@2: 		ERightToLeftOverrideState = ERightToLeftOverride
williamr@2: 		};
williamr@2: 
williamr@2: 	class TStackItem
williamr@2: 		{
williamr@2: 	public:
williamr@2: 		TUint8 iEmbeddingLevel;			// embedding level
williamr@2: 		TOverrideState iOverrideState;	// directional override state
williamr@2: 		TCategory iStartCategory;		// category that started this level; EOtherNeutral if none
williamr@2: 		};
williamr@2: 
williamr@2: public:
williamr@2: 	/**	The information needed during line reordering.
williamr@2: 	@internalComponent	*/
williamr@2: 	class TReorderContext
williamr@2: 		{
williamr@2: 	public:
williamr@2: 		void SetNextCategory(TChar::TBdCategory aCat);
williamr@2: 		void SetNextStrongCategory(TChar::TBdCategory aCat);
williamr@2: 	public:
williamr@2: 		/** Category at start of next line, or ON if at the end of the
williamr@2: 		paragraph. */
williamr@2: 		TCategory iNextCategory;
williamr@2: 		/** Which of L, R or AL appears first in the remainder of the
williamr@2: 		paragraph, or ON if none. */
williamr@2: 		TCategory iNextStrongCategory;
williamr@2: 		/** The run array for this line. */
williamr@2: 		TRunInfo* iRunInfo;
williamr@2: 		/** The length of iRunInfo. */
williamr@2: 		TInt iRuns;
williamr@2: 		/** Bitmap of categories currently present in iRunInfo. */
williamr@2: 		TUint32 iCategories;
williamr@2: 		/** Found by the algorithm to set iPreviousStrongCategory. */
williamr@2: 		TCategory iLastStrongCategory;
williamr@2: 		};
williamr@2: 
williamr@2: public:
williamr@2: 	static TInt GenerateBdRunArray(const TText* aText, TInt aLength,
williamr@2: 		TBidirectionalState::TRunInfo* aRun, TInt aMaxRuns);
williamr@2: 
williamr@2: private:
williamr@2: 	const TStackItem& State() const { return iStack[iStackLevel]; }
williamr@2: 	TCategory Push(TCategory aStartCategory);
williamr@2: 	TCategory Pop();
williamr@2: 
williamr@2: public:
williamr@2: 	TBidirectionalState(TChar::TBdCategory aPrevCat,
williamr@2: 		TChar::TBdCategory aPrevStrongCat, TBool aParRightToLeft);
williamr@2: 	void HandleBdControls(TReorderContext& aContext); 
williamr@2: 	void ResolveWeakTypesW1W2W3(TReorderContext& aContext);
williamr@2: 	void ResolveWeakTypesW4W5W6(TReorderContext& aContext); 
williamr@2: 	void ResolveWeakTypesW7(TReorderContext& aContext); 
williamr@2: 	void ResolveNeutralTypes(TReorderContext& aContext); 
williamr@2: 	void ResolveImplicitLevels(TReorderContext& aContext); 
williamr@2: 	void PrepareForNextLine(const TReorderContext& aContext);
williamr@2: 	void ReorderRuns(TReorderContext& aContext);
williamr@2: 	static TInt CatToNumber(TInt aCat);
williamr@2: 	static TCategory CharToBdCat(TChar::TBdCategory aCat);
williamr@2: 	static TCategory UintToBdCat(TUint aCat);
williamr@2: 	static void DeneutralizeRuns(TRunInfo* aStart, TRunInfo* aEnd,
williamr@2: 		TCategory aStartCategory, TCategory aEndCategory);
williamr@2: private:
williamr@2: 	TCategory iPreviousCategory;			// category at end of last line, or EStartOfParagraph if at start of par
williamr@2: 	TCategory iPreviousStrongCategory;		// L or R; derived from embedding level if at start of par
williamr@2: 	TInt16 iStackLevel;						// current stack level
williamr@2: 	TInt8 iPushesBeyond60;	// number of times Push called with iStackLevel == 60 and Left-To-Right category
williamr@2: 	TInt8 iPushesBeyond61;	// number of times Push called with iStackLevel == 61
williamr@2: 	TStackItem iStack[EMaxStackLevels];		// the stack of embedding levels
williamr@2: 	};
williamr@2: 
williamr@2: #endif // BIDI_H_