fontservices/textbase/sgdi/LinebreakComplex.cpp
author hgs
Mon, 12 Jul 2010 14:38:26 +0800
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201024_05
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// Copyright (c) 2003-2010 Nokia Corporation and/or its subsidiary(-ies).
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// All rights reserved.
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// This component and the accompanying materials are made available
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// under the terms of "Eclipse Public License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.eclipse.org/legal/epl-v10.html".
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//
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// Initial Contributors:
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// Nokia Corporation - initial contribution.
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//
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// Contributors:
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//
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// Description:
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//
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#include <e32std.h>
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#include <e32svr.h>
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#include "LineBreak.h"
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#include "LineBreakImp.h"
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#include "GlyphSel.h"
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const TText16 KThaiCodePageStart = 0x0E00;
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const TText16 KThaiCodePageEnd   = 0x0E5C;
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const TUint KNumThaiCharacters = KThaiCodePageEnd - KThaiCodePageStart;
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/**
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 Ecanpsulates rules for when Thai character sequence line breaking.
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@internalComponent
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*/
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class ThaiLinebreakRules
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	{
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public:
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	enum TCharClassification
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		{
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		EOutOfRange,
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		EConsOAng,
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		EConsYoYak,
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		EConsHoHip,
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		EConsWoWean,
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		EConsDigraph,
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		EConsOther,
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		EPostVowelA,
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		EPostVowelAA,
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		EPostVowelOther,
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		EPreVowel,
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		EDepMaiHanAkat,
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		EDepSaraI,
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		EDepOther,
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		// marker for end
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		EMaxClassification
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		};
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	enum
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		{
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		KOutOfRangeFlag = 1 << EOutOfRange,
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		KConsOAngFlag = 1 << EConsOAng,
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		KConsYoYakFlag = 1 << EConsYoYak,
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		KConsHoHipFlag = 1 << EConsHoHip,
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		KConsWoWeanFlag = 1 << EConsWoWean,
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		KConsDigraphFlag = 1 << EConsDigraph,
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		KConsOtherFlag = 1 << EConsOther,
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		KPostVowelAFlag = 1 << EPostVowelA,
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		KPostVowelAAFlag = 1 << EPostVowelAA,
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		KPostVowelOtherFlag = 1 << EPostVowelOther,
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		KPreVowelFlag = 1 << EPreVowel,
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		KDepMaiHanAkatFlag = 1 << EDepMaiHanAkat,
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		KDepSaraIFlag = 1 << EDepSaraI,
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		KDepOtherFlag = 1 << EDepOther,
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		KSpecialDepFlags = KDepMaiHanAkatFlag | KDepSaraIFlag,
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		KPostVowelFlags = KPostVowelAFlag | KPostVowelAAFlag | KPostVowelOtherFlag,
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		KConsFlags = KConsOtherFlag | KConsDigraphFlag | KConsWoWeanFlag
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			| KConsHoHipFlag | KConsYoYakFlag | KConsOAngFlag,
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		KAllFlags = KOutOfRangeFlag | KConsOAngFlag | KConsYoYakFlag
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			| KConsHoHipFlag | KConsWoWeanFlag | KConsDigraphFlag
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			| KConsOtherFlag | KPostVowelAFlag | KPostVowelAAFlag
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			| KPostVowelOtherFlag | KPreVowelFlag | KDepMaiHanAkatFlag
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			| KDepSaraIFlag | KDepOtherFlag
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		};
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	/** Returns the Thai linebreaking class of the character. */
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	static TCharClassification Class(TInt aChar);
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	/** Returns true if aChar is a combining character according to aBreaker. */
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	static TBool IsCombiningChar(TInt aChar, const MLineBreaker& aBreaker);
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	/** Returns the Thai linebreaking class of the character at (*aChar),
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	searching backwards for the base character if it is foreign and of type CM.
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	@param aChar The position of the character within the string.
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	@param aStart The start of the string.
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	@param aBreaker The line breaker to query for line breaking class.
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	*/
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	static TCharClassification DerivedClass(const TText* aChar,
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		const TText* aStart, const MLineBreaker& aBreaker);
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	/**
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	 Gets the line break rule for the previous and current character pair
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	@param aPrevClass Class of the previous character.
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	@param aClass Class of the current character.
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	@return the rule code corresponding to the input pair.
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	*/
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	static TBool BreakAllowedBetween(
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		TCharClassification aPrevClass, TCharClassification aClass);
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	/** Returns whether a line break is allowed before the SA character at
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	(*aChar).
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	@param aChar The position of the character within the string.
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	@param aStart The start of the string.
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	@param aBreaker The line breaker to query for line breaking class.
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	*/
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	static TBool BreakAllowedAt(const TText* aChar,
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		const TText* aStart, const MLineBreaker& aBreaker);
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	/**
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	 Classification of each character
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	*/
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	static const TUint8 KCharClassifications[KNumThaiCharacters];
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	/**
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	 Rules table of prev to next character
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	*/
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	static const TUint32 KRules[EMaxClassification];
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	};
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const TUint8 ThaiLinebreakRules::KCharClassifications[KNumThaiCharacters] = 
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	{
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	EOutOfRange,	// 0x0E00
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	EConsOther,		// 0x0E01
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	EConsOther,		// 0x0E02
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	EConsOther,		// 0x0E03
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	EConsOther,		// 0x0E04
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	EConsOther,		// 0x0E05
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	EConsOther,		// 0x0E06
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	EConsDigraph,	// 0x0E07
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	EConsOther,		// 0x0E08
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	EConsOther,		// 0x0E09
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	EConsOther,		// 0x0E0A
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	EConsOther,		// 0x0E0B
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	EConsOther,		// 0x0E0C
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	EConsOther,		// 0x0E0D
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	EConsOther,		// 0x0E0E
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	EConsOther,		// 0x0E0F
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	EConsOther,		// 0x0E10
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	EConsOther,		// 0x0E11
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	EConsOther,		// 0x0E12
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	EConsOther,		// 0x0E13
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	EConsOther,		// 0x0E14
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	EConsOther,		// 0x0E15
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	EConsOther,		// 0x0E16
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	EConsOther,		// 0x0E17
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	EConsOther,		// 0x0E18
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	EConsDigraph,	// 0x0E19
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	EConsOther,		// 0x0E1A
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	EConsOther,		// 0x0E1B
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	EConsOther,		// 0x0E1C
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	EConsOther,		// 0x0E1D
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	EConsOther,		// 0x0E1E
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	EConsOther,		// 0x0E1F
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	EConsOther,		// 0x0E20
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	EConsDigraph,	// 0x0E21
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	EConsYoYak,		// 0x0E22
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	EConsDigraph,	// 0x0E23
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	EConsOther,		// 0x0E24
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	EConsDigraph,	// 0x0E25
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	EConsOther,		// 0x0E26
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	EConsWoWean,	// 0x0E27
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	EConsOther,		// 0x0E28
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	EConsOther,		// 0x0E29
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	EConsOther,		// 0x0E2A
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	EConsHoHip,		// 0x0E2B
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	EConsOther,		// 0x0E2C
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	EConsOAng,		// 0x0E2D
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	EConsOther,		// 0x0E2E
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	EOutOfRange,	// 0x0E2F
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	EPostVowelA,	// 0x0E30
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	EDepMaiHanAkat,	// 0x0E31
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	EPostVowelAA,	// 0x0E32
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	EPostVowelOther,// 0x0E33
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	EDepSaraI,		// 0x0E34
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	EDepOther,		// 0x0E35
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	EDepOther,		// 0x0E36
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	EDepOther,		// 0x0E37
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	EDepOther,		// 0x0E38
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	EDepOther,		// 0x0E39
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	EDepOther,		// 0x0E3A
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	EOutOfRange,	// 0x0E3B
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	EOutOfRange,	// 0x0E3C
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	EOutOfRange,	// 0x0E3D
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	EOutOfRange,	// 0x0E3E
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   195
	EOutOfRange,	// 0x0E3F
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parents:
diff changeset
   196
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parents:
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   197
	EPreVowel,		// 0x0E40
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parents:
diff changeset
   198
	EPreVowel,		// 0x0E41
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parents:
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   199
	EPreVowel,		// 0x0E42
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hgs
parents:
diff changeset
   200
	EPreVowel,		// 0x0E43
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hgs
parents:
diff changeset
   201
	EPreVowel,		// 0x0E44
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hgs
parents:
diff changeset
   202
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parents:
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   203
	EPostVowelOther,// 0x0E45
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parents:
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   204
	EOutOfRange,	// 0x0E46
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hgs
parents:
diff changeset
   205
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parents:
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   206
	EDepOther,		// 0x0E47
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parents:
diff changeset
   207
	EDepOther,		// 0x0E48
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parents:
diff changeset
   208
	EDepOther,		// 0x0E49
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hgs
parents:
diff changeset
   209
	EDepOther,		// 0x0E4A
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parents:
diff changeset
   210
	EDepOther,		// 0x0E4B
662fa7de7023 201024_05
hgs
parents:
diff changeset
   211
	EDepOther,		// 0x0E4C
662fa7de7023 201024_05
hgs
parents:
diff changeset
   212
	EDepOther,		// 0x0E4D
662fa7de7023 201024_05
hgs
parents:
diff changeset
   213
	EDepOther,		// 0x0E4E
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hgs
parents:
diff changeset
   214
	EOutOfRange,	// 0x0E4F
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hgs
parents:
diff changeset
   215
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hgs
parents:
diff changeset
   216
	EOutOfRange,		// 0x0E50
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hgs
parents:
diff changeset
   217
	EOutOfRange,		// 0x0E51
662fa7de7023 201024_05
hgs
parents:
diff changeset
   218
	EOutOfRange,		// 0x0E52
662fa7de7023 201024_05
hgs
parents:
diff changeset
   219
	EOutOfRange,		// 0x0E53
662fa7de7023 201024_05
hgs
parents:
diff changeset
   220
	EOutOfRange,		// 0x0E54
662fa7de7023 201024_05
hgs
parents:
diff changeset
   221
	EOutOfRange,		// 0x0E55
662fa7de7023 201024_05
hgs
parents:
diff changeset
   222
	EOutOfRange,		// 0x0E56
662fa7de7023 201024_05
hgs
parents:
diff changeset
   223
	EOutOfRange,		// 0x0E57
662fa7de7023 201024_05
hgs
parents:
diff changeset
   224
	EOutOfRange,		// 0x0E58
662fa7de7023 201024_05
hgs
parents:
diff changeset
   225
	EOutOfRange,		// 0x0E59
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hgs
parents:
diff changeset
   226
	EOutOfRange,		// 0x0E5A
662fa7de7023 201024_05
hgs
parents:
diff changeset
   227
	EOutOfRange			// 0x0E5B
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hgs
parents:
diff changeset
   228
	};
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parents:
diff changeset
   229
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   230
const TUint32 KNormalBreaksBeforeCons =
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parents:
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   231
	ThaiLinebreakRules::KPreVowelFlag
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parents:
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   232
	| ThaiLinebreakRules::KConsOtherFlag
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parents:
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   233
	| ThaiLinebreakRules::KConsDigraphFlag
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parents:
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   234
	| ThaiLinebreakRules::KConsHoHipFlag
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parents:
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   235
	| ThaiLinebreakRules::KOutOfRangeFlag;
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hgs
parents:
diff changeset
   236
const TUint32 KNormalBreaksBeforePostVowel =
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hgs
parents:
diff changeset
   237
	ThaiLinebreakRules::KPreVowelFlag
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parents:
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   238
	| ThaiLinebreakRules::KPostVowelFlags
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hgs
parents:
diff changeset
   239
	| ThaiLinebreakRules::KConsFlags
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parents:
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   240
	| ThaiLinebreakRules::KOutOfRangeFlag;
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hgs
parents:
diff changeset
   241
const TUint32 ThaiLinebreakRules::KRules[EMaxClassification] =
662fa7de7023 201024_05
hgs
parents:
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   242
	{
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parents:
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   243
	/* Prev Char EOutOfRange */
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hgs
parents:
diff changeset
   244
	KAllFlags - KOutOfRangeFlag,
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hgs
parents:
diff changeset
   245
	/* Prev Char EConsOAng */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   246
	KNormalBreaksBeforeCons,
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hgs
parents:
diff changeset
   247
	/* Prev Char EConsYoYak */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   248
	KNormalBreaksBeforeCons,
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hgs
parents:
diff changeset
   249
	/* Prev Char EConsHoHip */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   250
	KNormalBreaksBeforeCons - KConsDigraphFlag,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   251
	/* Prev Char EConsWoWean */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   252
	KNormalBreaksBeforeCons - KConsDigraphFlag - KConsHoHipFlag,
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hgs
parents:
diff changeset
   253
	/* Prev Char EConsDigraph */
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hgs
parents:
diff changeset
   254
	KNormalBreaksBeforeCons,
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hgs
parents:
diff changeset
   255
	/* Prev Char EConsOther */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   256
	KNormalBreaksBeforeCons,
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hgs
parents:
diff changeset
   257
	/* Prev Char EPostVowelA */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   258
	KNormalBreaksBeforePostVowel,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   259
	/* Prev Char EPostVowelAA */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   260
	KNormalBreaksBeforePostVowel - KPostVowelAFlag,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   261
	/* Prev Char EPostVowelOther */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   262
	KNormalBreaksBeforePostVowel,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   263
	/* Prev Char EPreVowel */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   264
	KPreVowelFlag | KPostVowelFlags | KOutOfRangeFlag,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   265
	/* Prev Char EDepMaiHanAkat */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   266
	KSpecialDepFlags | KPreVowelFlag | KPostVowelAAFlag
662fa7de7023 201024_05
hgs
parents:
diff changeset
   267
		| KPostVowelAFlag | KOutOfRangeFlag,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   268
	/* Prev Char EDepSaraI */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   269
	KSpecialDepFlags | KPreVowelFlag | KPostVowelAAFlag
662fa7de7023 201024_05
hgs
parents:
diff changeset
   270
		| KPostVowelAFlag | KOutOfRangeFlag,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   271
	/* Prev Char EDepOther */
662fa7de7023 201024_05
hgs
parents:
diff changeset
   272
	KSpecialDepFlags | KPreVowelFlag | KPostVowelAAFlag
662fa7de7023 201024_05
hgs
parents:
diff changeset
   273
		| KPostVowelAFlag | KConsOtherFlag | KConsDigraphFlag
662fa7de7023 201024_05
hgs
parents:
diff changeset
   274
		| KConsWoWeanFlag | KConsHoHipFlag | KOutOfRangeFlag
662fa7de7023 201024_05
hgs
parents:
diff changeset
   275
	};
662fa7de7023 201024_05
hgs
parents:
diff changeset
   276
662fa7de7023 201024_05
hgs
parents:
diff changeset
   277
ThaiLinebreakRules::TCharClassification ThaiLinebreakRules::Class(TInt a)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   278
    {
662fa7de7023 201024_05
hgs
parents:
diff changeset
   279
	return static_cast<TCharClassification>(
662fa7de7023 201024_05
hgs
parents:
diff changeset
   280
		(KThaiCodePageStart <= a && a < KThaiCodePageEnd) ?
662fa7de7023 201024_05
hgs
parents:
diff changeset
   281
			KCharClassifications[a - KThaiCodePageStart] :
662fa7de7023 201024_05
hgs
parents:
diff changeset
   282
			EOutOfRange);
662fa7de7023 201024_05
hgs
parents:
diff changeset
   283
    }
662fa7de7023 201024_05
hgs
parents:
diff changeset
   284
662fa7de7023 201024_05
hgs
parents:
diff changeset
   285
TBool ThaiLinebreakRules::IsCombiningChar(TInt aChar,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   286
	const MLineBreaker& aBreaker)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   287
	{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   288
	TUint dummy1, dummy2;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   289
	return aBreaker.LineBreakClass(aChar, dummy1, dummy2) == MLineBreaker::ECmLineBreakClass;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   290
	}
662fa7de7023 201024_05
hgs
parents:
diff changeset
   291
662fa7de7023 201024_05
hgs
parents:
diff changeset
   292
ThaiLinebreakRules::TCharClassification ThaiLinebreakRules::DerivedClass(
662fa7de7023 201024_05
hgs
parents:
diff changeset
   293
	const TText* aChar, const TText* aStart, const MLineBreaker& aBreaker)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   294
	{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   295
	ThaiLinebreakRules::TCharClassification c = Class(*aChar);
662fa7de7023 201024_05
hgs
parents:
diff changeset
   296
	while (c == EOutOfRange && aChar != aStart
662fa7de7023 201024_05
hgs
parents:
diff changeset
   297
		&& IsCombiningChar(*aChar, aBreaker))
662fa7de7023 201024_05
hgs
parents:
diff changeset
   298
		{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   299
		--aChar;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   300
		c = Class(*aChar);
662fa7de7023 201024_05
hgs
parents:
diff changeset
   301
		}
662fa7de7023 201024_05
hgs
parents:
diff changeset
   302
	return c;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   303
	}
662fa7de7023 201024_05
hgs
parents:
diff changeset
   304
662fa7de7023 201024_05
hgs
parents:
diff changeset
   305
TBool ThaiLinebreakRules::BreakAllowedBetween(
662fa7de7023 201024_05
hgs
parents:
diff changeset
   306
	ThaiLinebreakRules::TCharClassification aClass,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   307
	ThaiLinebreakRules::TCharClassification aNextClass)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   308
	{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   309
	return KRules[aClass] & (1 << aNextClass);
662fa7de7023 201024_05
hgs
parents:
diff changeset
   310
	}
662fa7de7023 201024_05
hgs
parents:
diff changeset
   311
662fa7de7023 201024_05
hgs
parents:
diff changeset
   312
TBool ThaiLinebreakRules::BreakAllowedAt(const TText* aChar,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   313
	const TText* aStart, const MLineBreaker& aBreaker)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   314
	{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   315
	__ASSERT_DEBUG(aStart < aChar, User::Invariant());
662fa7de7023 201024_05
hgs
parents:
diff changeset
   316
	TCharClassification c = Class(*aChar);
662fa7de7023 201024_05
hgs
parents:
diff changeset
   317
	if (c == EOutOfRange && IsCombiningChar(*aChar, aBreaker))
662fa7de7023 201024_05
hgs
parents:
diff changeset
   318
		return EFalse;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   319
	return BreakAllowedBetween(DerivedClass(aChar - 1, aStart, aBreaker), c);
662fa7de7023 201024_05
hgs
parents:
diff changeset
   320
	}
662fa7de7023 201024_05
hgs
parents:
diff changeset
   321
662fa7de7023 201024_05
hgs
parents:
diff changeset
   322
/**
662fa7de7023 201024_05
hgs
parents:
diff changeset
   323
 Returns whether a line break is possible within a run of characters all having
662fa7de7023 201024_05
hgs
parents:
diff changeset
   324
 the class ESaLineBreakClass (Complex content). Languages with Unicocde
662fa7de7023 201024_05
hgs
parents:
diff changeset
   325
 characters having such a class include: Thai, Lao, Myanmar and Khmer. This
662fa7de7023 201024_05
hgs
parents:
diff changeset
   326
 default implementation of the GetLineBreakInContext() method only supports the
662fa7de7023 201024_05
hgs
parents:
diff changeset
   327
 Thai script. Breaks are determined in Thai based on a simple understanding of
662fa7de7023 201024_05
hgs
parents:
diff changeset
   328
 syllable boundaries. When characters from the other unsupported Sa class
662fa7de7023 201024_05
hgs
parents:
diff changeset
   329
 languages are found the method exits with EFalse.
662fa7de7023 201024_05
hgs
parents:
diff changeset
   330
@param aText
662fa7de7023 201024_05
hgs
parents:
diff changeset
   331
 The text to be searched, which is a contiguous run of characters of class SA
662fa7de7023 201024_05
hgs
parents:
diff changeset
   332
 (or CM attatched to SA). The break position may be restricted further by
662fa7de7023 201024_05
hgs
parents:
diff changeset
   333
 aMinBreakPos and aMaxBreakPos, but more text is provided for extra context
662fa7de7023 201024_05
hgs
parents:
diff changeset
   334
 should it be needed.
662fa7de7023 201024_05
hgs
parents:
diff changeset
   335
@param aMinBreakPos
662fa7de7023 201024_05
hgs
parents:
diff changeset
   336
 The start of the text to be considered for line breaks.
662fa7de7023 201024_05
hgs
parents:
diff changeset
   337
@param aMaxBreakPos
662fa7de7023 201024_05
hgs
parents:
diff changeset
   338
 The end of the text to be considered for line breaks.
662fa7de7023 201024_05
hgs
parents:
diff changeset
   339
@param aForwards
662fa7de7023 201024_05
hgs
parents:
diff changeset
   340
 ETrue if aBreakPos is to be set with the first legal break position,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   341
 EFalse if aBreakPos is to be set with the last legal break position.
662fa7de7023 201024_05
hgs
parents:
diff changeset
   342
@param aBreakPos
662fa7de7023 201024_05
hgs
parents:
diff changeset
   343
 If break position found on exit its value is >= Min and <= Max 
662fa7de7023 201024_05
hgs
parents:
diff changeset
   344
 positions supplied.
662fa7de7023 201024_05
hgs
parents:
diff changeset
   345
@return TBool
662fa7de7023 201024_05
hgs
parents:
diff changeset
   346
 ETrue if and only if a legal break was found, EFalse otherwise.
662fa7de7023 201024_05
hgs
parents:
diff changeset
   347
@publishedAll
662fa7de7023 201024_05
hgs
parents:
diff changeset
   348
@released
662fa7de7023 201024_05
hgs
parents:
diff changeset
   349
*/
662fa7de7023 201024_05
hgs
parents:
diff changeset
   350
EXPORT_C TBool MLineBreaker::GetLineBreakInContext(const TDesC16& aText,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   351
		TInt aMinBreakPos, TInt aMaxBreakPos, TBool aForwards,
662fa7de7023 201024_05
hgs
parents:
diff changeset
   352
		TInt& aBreakPos) const
662fa7de7023 201024_05
hgs
parents:
diff changeset
   353
	{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   354
	__ASSERT_DEBUG (0 <= aMinBreakPos && aMaxBreakPos <= aText.Length(), 
662fa7de7023 201024_05
hgs
parents:
diff changeset
   355
			Panic(ELineBreakPanic_InvalidInputParam));
662fa7de7023 201024_05
hgs
parents:
diff changeset
   356
662fa7de7023 201024_05
hgs
parents:
diff changeset
   357
	TInt length = aText.Length();
662fa7de7023 201024_05
hgs
parents:
diff changeset
   358
662fa7de7023 201024_05
hgs
parents:
diff changeset
   359
	if (aMinBreakPos < 1)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   360
		aMinBreakPos = 1;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   361
	if (length - 1 < aMaxBreakPos)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   362
		aMaxBreakPos = length - 1;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   363
	if (aMaxBreakPos < aMinBreakPos)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   364
		return EFalse;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   365
662fa7de7023 201024_05
hgs
parents:
diff changeset
   366
	const TText16* text = aText.Ptr();
662fa7de7023 201024_05
hgs
parents:
diff changeset
   367
662fa7de7023 201024_05
hgs
parents:
diff changeset
   368
	if (*text == KZeroWidthSpace)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   369
		{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   370
		aBreakPos = aMinBreakPos;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   371
		return ETrue;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   372
		}
662fa7de7023 201024_05
hgs
parents:
diff changeset
   373
	else if (*(text+length-1) == KZeroWidthSpace)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   374
		return EFalse;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   375
	
662fa7de7023 201024_05
hgs
parents:
diff changeset
   376
	TInt start = aForwards? aMinBreakPos : aMaxBreakPos;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   377
	TInt end = aForwards? aMaxBreakPos + 1 : aMinBreakPos - 1;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   378
	TInt direction = aForwards? 1 : -1;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   379
	for (TInt i = start; i != end; i += direction)
662fa7de7023 201024_05
hgs
parents:
diff changeset
   380
		{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   381
		if (ThaiLinebreakRules::BreakAllowedAt(text + i, text, *this))
662fa7de7023 201024_05
hgs
parents:
diff changeset
   382
			{
662fa7de7023 201024_05
hgs
parents:
diff changeset
   383
			aBreakPos = i;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   384
			return ETrue;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   385
			}
662fa7de7023 201024_05
hgs
parents:
diff changeset
   386
		}
662fa7de7023 201024_05
hgs
parents:
diff changeset
   387
	return EFalse;
662fa7de7023 201024_05
hgs
parents:
diff changeset
   388
	}