// Copyright (c) 1997-2009 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:

// The Unicode collation system.

// 

//

#include "collateimp.h"

#include "foldtable.inl"

#include <collate.h>

#include <unicode.h>

#include "u32std.h"

// maximum size of string which has its own sort key

// 16 instead of 8, in case all supplementary characters

static const TInt KKeyedStringBufferSize = 16;

// Creates a one or two collation keys sequence corresponding to the input character.

// Returns the number of keys output.

static TInt CreateDefaultCollationKeySequence(TInt aChar, TCollationKey* aBuffer)

	{

	if (aChar >= 0x3400 && aChar <= 0x9FFF)	// CJK

		{

		aBuffer[0].iLow = (TUint32)aChar << 16 | 0x0105;

		aBuffer[0].iHigh = aChar;

		return 1;//Collation key sequence consists of 1 key

		}

	aBuffer[0].iLow = 0xFF800000 | ((aChar << 1) & 0x3F0000) | 0x0104;	// no stop bit

	aBuffer[0].iHigh = 1;

	aBuffer[1].iLow = (aChar << 16) | 0x80000105;		// stop bit

	aBuffer[1].iHigh = 0;

	return 2;//Collation key sequence consists of 2 keys

	}

// Finds a character's key in the main index, or returns -1 if it is not there

static TInt FindCollationKeyIndex(TInt aChar, const TCollationKeyTable& aTable)

	{

	TInt n = aTable.iIndices;

	const TUint32 *base = aTable.iIndex;

	const TUint32 *start = base;

	const TUint32 *end = aTable.iIndex + n - 1;

	const TUint32 *p = base;

	TInt currentCharLength = 0;

	while (n > 0)

		{

		TInt pivot = n / 2;

		p += pivot;

		if ((p < start) || (p > end)) 

			{

			break;

			}

		TInt c = *p >> 16;

		if (TChar::IsHighSurrogate( (TText16)c ))

			{

			if ((p < end) && (TChar::IsLowSurrogate( (TText16)((*(p+1))>>16) )))

				{

				currentCharLength = 2;

				c = TChar::JoinSurrogate( (TText16)(*p>>16), (TText16)((*(p+1))>>16) );

				}

			}

		else if (TChar::IsLowSurrogate( (TText16)c ))

			{

			if ((p > start) && (TChar::IsHighSurrogate( (TText16)((*(p-1))>>16) )))

				{

				p--;

				pivot = pivot - 1;

				currentCharLength = 2;

				c = TChar::JoinSurrogate( (TText16)(*p>>16), (TText16)((*(p+1))>>16) );

				}

			}

		else

			{

			currentCharLength = 1;

			}

		if (aChar == c)		// found it

			{

			return *p & 0xFFFF;

			}

		if (aChar < c)		// it's before

			{

			n = pivot;

			}

		else					// it's after

			{

			ASSERT(currentCharLength != 0);

			base = p + currentCharLength;

			n -= pivot + currentCharLength;

			}

		p = base;

		}

	return -1;

	}

static void ProcessKeys(TUint32& aKey1, TUint32& aKey2, TUint aFlags)

	{

	if (aFlags & TCollationMethod::EFoldCase)

		{

		static const TUint case_fold_table[21] =

			{ 0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x2, 0x3, 0x4, 0x5, 0x6,

			  0xD, 0xE, 0xF, 0x10, 0x11, 0x12, 0x13, 0x14 };

		aKey1 = case_fold_table[aKey1];

		aKey2 = case_fold_table[aKey2];

		}					

	if (aFlags & TCollationMethod::ESwapCase)

		{

		static const TUint case_swap_table[21] =

			{ 0, 0x1, 0x8, 0x9, 0xA, 0xB, 0xC, 0x7, 0x2, 0x3, 0x4, 0x5, 0x6,

			  0xD, 0xE, 0xF, 0x10, 0x11, 0x12, 0x13, 0x14 };

		aKey1 = case_swap_table[aKey1];

		aKey2 = case_swap_table[aKey2];

		}

	if (aFlags & TCollationMethod::ESwapKana)

		{

		static const TUint kana_swap_table[21] =

			{ 0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xA, 0xB, 0xC,

			  0x13, 0x14, 0xD, 0xE, 0xF, 0x10, 0x11, 0x12 };

		aKey1 = kana_swap_table[aKey1];

		aKey2 = kana_swap_table[aKey2];

		}

	}

// Returns the position of the character in the string, or aLength if it is not present.

// If aChar is found but it is preceded by aEscapeChar (aEscapeChar != 0), then the search continues.

static TInt FindCharacter(TInt aChar, TInt aEscapeChar, const TUint16* aString, TInt aLength)

	{

	TBool isEscaped = EFalse;

	for(TInt pos=0;pos!=aLength;++pos,++aString)

		{

		if(isEscaped) 

			{ 

			isEscaped = EFalse; 

			} 

		else if(*aString == aEscapeChar) 

			{ 

			isEscaped = ETrue; 

			} 

		else if(*aString == aChar) 

			{ 

			if(!isEscaped)

				{

				return pos; 

				}

			}		

		}

	return aLength;

	}

/*

The standard collation data, containing keys for all the WGL4 characters, plus

commonly-used control characters and spaces. Generated by COLTAB.

*/

static const TUint32 TheKey[] = 

	{

	0x21e0112,0x21e0113,0x2260112,0x2260112,0x2260113,0x2740112,0x2740113,0x6c60178,

	0x266017a,0x6c70179,0x6c60178,0x266017a,0x6c90179,0x6c60178,0x266017a,0x6cd0179,

	0x6c80178,0x266017a,0x6c90179,0x6c80178,0x266017a,0x6cd0179,0x6ca0178,0x266017a,

	0x6cd0179,0x6cc0178,0x266017a,0x6cd0179,0x6f70110,0x2650112,0x8050111,0x74b0110,

	0x78d0111,0x74b0110,0x7bd0111,0x78d0110,0x7a10111,0x78d0128,0x7a10129,0x7bd0110,

	0x2290113,0x7bd0128,0x2290113,0x7ed0128,0x8050111,0x805dd10,0x71f0111,0x805dd28,

	0x71f0129,0x85ddd10,0x85d0111,0x8750150,0x7e50151,0x9060110,0x7ed0111,0x3,

	0x201010b,0x202010b,0x203010b,0x204010b,0x205010b,0x206010b,0x207010b,0x208010b,

	0x209010b,0x2090113,0x209016f,0x209020b,0x209130b,0x209160b,0x209180b,0x2091d0b,

	0x209240b,0x209280b,0x2092a0b,0x2092f0b,0x209330b,0x209360b,0x209390b,0x2093b0b,

	0x2093f0b,0x2096b0b,0x20b010b,0x20c010b,0x20d010b,0x20d016f,0x20e010b,0x20f010b,

	0x210010b,0x211010b,0x214010b,0x21a010b,0x21c010b,0x21e010b,0x21f010b,0x221010b,

	0x222010b,0x226010b,0x229010b,0x22d010b,0x22e010b,0x22f010b,0x230010b,0x231010b,

	0x232010b,0x233010b,0x234010b,0x235010b,0x236010b,0x237010b,0x23c010b,0x23d010b,

	0x23e010b,0x23f010b,0x240010b,0x241010b,0x242010b,0x243010b,0x25e010b,0x25f010b,

	0x260010b,0x261010b,0x262010b,0x263010b,0x265010b,0x266010b,0x267010b,0x268010b,

	0x269010b,0x26a010b,0x26c010b,0x26e010b,0x26f010b,0x270010b,0x274010b,0x2ac010b,

	0x2ad010b,0x2af010b,0x2d6010b,0x2ff010b,0x300010b,0x301010b,0x302010b,0x303010b,

	0x304010b,0x317010b,0x35c010b,0x35f010b,0x366010b,0x368010b,0x369010b,0x36a010b,

	0x36b010b,0x36c010b,0x36d010b,0x36e010b,0x36f010b,0x370010b,0x371010b,0x372010b,

	0x374010b,0x375010b,0x378010b,0x37c010b,0x37d010b,0x381010b,0x382010b,0x38a010b,

	0x38c010b,0x3a2010b,0x3b9010b,0x3bb010b,0x3bc010b,0x42f010b,0x43d010b,0x44d010b,

	0x44e010b,0x4d6010b,0x4d8010b,0x4e2010b,0x4e6010b,0x4ea010b,0x4ee010b,0x4f2010b,

	0x4fa010b,0x502010b,0x50a010b,0x512010b,0x526010b,0x527010b,0x528010b,0x529010b,

	0x52a010b,0x52b010b,0x52c010b,0x52d010b,0x52e010b,0x52f010b,0x530010b,0x531010b,

	0x532010b,0x533010b,0x534010b,0x535010b,0x536010b,0x537010b,0x538010b,0x539010b,

	0x53a010b,0x53b010b,0x53c010b,0x53d010b,0x53e010b,0x53f010b,0x540010b,0x541010b,

	0x542010b,0x556010b,0x55a010b,0x55e010b,0x562010b,0x566010b,0x567010b,0x568010b,

	0x569010b,0x56c010b,0x56d010b,0x576010b,0x577010b,0x578010b,0x57e010b,0x586010b,

	0x588010b,0x590010b,0x596010b,0x597010b,0x59b010b,0x5a4010b,0x5a5010b,0x5b2010b,

	0x5f0010b,0x5f1010b,0x5f2010b,0x5f6010b,0x5f8010b,0x616010b,0x619010b,0x61b010b,

	0x61c010b,0x620010b,0x621010b,0x6b4010b,0x6b5010b,0x1309,0x1609,0x1809,

	0x1d09,0x2209,0x2409,0x2809,0x2f09,0x3009,0x3309,0x3609,

	0x3909,0x3b09,0x4109,0x2c20109,0x2c30109,0x2c40109,0x2c50109,0x2c60109,

	0x2cd0109,0x2ce0109,0x2d10109,0x2d50109,0x2fa0109,0x6c50109,0x6c60109,0x6c60151,

	0x6c70109,0x6c70151,0x6c80109,0x6c80151,0x6c90109,0x6ca0109,0x6cb0109,0x6cc0109,

	0x6cd0109,0x6ce0109,0x6cf0109,0x6cf0121,0x6cf0151,0x6d30109,0x6d30121,0x6e30109,

	0x6e30121,0x6f70109,0x6f70121,0x7030109,0x7030121,0x7070109,0x7070121,0x7170109,

	0x7170121,0x71f0109,0x71f0121,0x74b0109,0x74b0121,0x74f0109,0x7530109,0x7530121,

	0x7730109,0x7730121,0x77f0109,0x77f0121,0x78d0109,0x78d0121,0x7910109,0x7a10109,

	0x7a10121,0x7b10109,0x7b10121,0x7bd0109,0x7bd0115,0x7bd0121,0x7c50109,0x7c50121,

	0x7e50109,0x7e50121,0x7ed0109,0x7ed0121,0x7ed0151,0x8010109,0x8010121,0x8050109,

	0x8050121,0x8050151,0x80d0109,0x80d0121,0x81d0109,0x81d0121,0x8290109,0x8290121,

	0x8310109,0x8350109,0x8350121,0x85d0109,0x85d0121,0x85dde11,0x8750109,0x8750121,

	0x8790109,0x8790121,0x88d0109,0x88d0121,0x8a50109,0x8a50121,0x8b10109,0x8b10121,

	0x8b90109,0x8b90121,0x8bd0109,0x8bd0121,0x8c90109,0x8c90121,0x8e90109,0x8e90121,

	0x9360109,0x9360121,0x9370109,0x9370121,0x9380109,0x9380121,0x9390109,0x9390121,

	0x93a0109,0x93a0121,0x93d0109,0x93d0121,0x93e0109,0x93e0121,0x93f0109,0x93f0121,

	0x9400109,0x9400121,0x9420109,0x9420121,0x9430109,0x9430121,0x9440109,0x9440111,

	0x9440121,0x9450109,0x9450121,0x9460109,0x9460121,0x9470109,0x9470121,0x9480109,

	0x9480121,0x94a0109,0x94a0121,0x94b0109,0x94b0121,0x94c0109,0x94c0121,0x94d0109,

	0x94d0121,0x94e0109,0x94e0121,0x94f0109,0x94f0121,0x9500109,0x9500121,0x9510109,

	0x9510121,0x95a0109,0x95a0121,0x9660109,0x9660121,0x96a0109,0x96a0121,0x96e0109,

	0x96e0121,0x9720109,0x9720121,0x97e0109,0x97e0121,0x9820109,0x9820121,0x98a0109,

	0x98a0121,0x98e0109,0x98e0121,0x9920109,0x9920121,0x99a0109,0x99a0121,0x99e0109,

	0x99e0121,0x9a60109,0x9a60121,0x9aa0109,0x9aa0121,0x9ae0109,0x9ae0121,0x9b20109,

	0x9b20121,0x9ca0109,0x9ca0121,0x9ce0109,0x9ce0121,0x9d20109,0x9d20121,0x9d60109,

	0x9d60121,0x9e60109,0x9e60121,0x9ea0109,0x9ea0121,0x9f20109,0x9f20121,0x9fe0109,

	0x9fe0121,0xa020109,0xa020121,0xa0a0109,0xa0a0121,0xa120109,0xa120121,0xa160109,

	0xa160121,0xa260109,0xa260121,0xa2a0109,0xa2a0121,0xa460109,0xa460121,0xa4e0109,

	0xa4e0121,0xa660109,0xa660121,0xa6a0109,0xa6a0121,0xa6e0109,0xa6e0121,0xa720109,

	0xa720121,0xa760109,0xa760121,0xa7a0109,0xa7a0121,0xa820109,0xa820121,0xa860109,

	0xa860121,0xa8a0109,0xa8a0121,

	};

static const TUint32 TheIndex[] = 

	{

	0x37,0x10037,0x20037,0x30037,0x40037,0x50037,0x60037,0x70037,

	0x80037,0x90038,0xa0039,0xb003a,0xc003b,0xd003c,0xe0037,0xf0037,

	0x100037,0x110037,0x120037,0x130037,0x140037,0x150037,0x160037,0x170037,

	0x180037,0x190037,0x1a0037,0x1b0037,0x1c0037,0x1d0037,0x1e0037,0x1f0037,

	0x200040,0x21005d,0x22006a,0x230080,0x24010d,0x250081,0x26007f,0x270063,

	0x280070,0x290071,0x2a007b,0x2b0096,0x2c005a,0x2d0053,0x2e0061,0x2f007c,

	0x300115,0x310116,0x320118,0x33011a,0x34011c,0x35011d,0x36011e,0x37011f,

	0x380120,0x390121,0x3a005c,0x3b005b,0x3c009a,0x3d009b,0x3e009c,0x3f005f,

	0x40007a,0x410123,0x420128,0x43012a,0x44012c,0x450132,0x460134,0x470137,

	0x480139,0x49013d,0x4a0140,0x4b0142,0x4c0145,0x4d0149,0x4e014b,0x4f0150,

	0x500155,0x510157,0x52015a,0x53015c,0x54015f,0x550163,0x560165,0x570167,

	0x580169,0x59016b,0x5a016d,0x5b0072,0x5c007e,0x5d0073,0x5e0047,0x5f0043,

	0x600045,0x610122,0x620127,0x630129,0x64012b,0x650131,0x660133,0x670136,

	0x680138,0x69013c,0x6a013f,0x6b0141,0x6c0143,0x6d0148,0x6e014a,0x6f014f,

	0x700154,0x710156,0x720159,0x73015b,0x74015e,0x750162,0x760164,0x770166,

	0x780168,0x79016a,0x7a016c,0x7b0074,0x7c009e,0x7d0075,0x7e00a0,0xa00042,

	0xa1005e,0xa2010c,0xa3010e,0xa4010b,0xa5010f,0xa6009f,0xa70076,0xa80049,

	0xa90078,0xaa0124,0xab006e,0xac009d,0xad0052,0xae0079,0xaf004f,0xb0008a,

	0xb10097,0xb20119,0xb3011b,0xb40044,0xb50187,0xb60077,0xb70062,0xb8004d,

	0xb90117,0xba0151,0xbb006f,0xbc000a,0xbd0007,0xbe0010,0xbf0060,0xc60126,

	0xd00130,0xd70099,0xd80153,0xde016f,0xdf0031,0xe60125,0xf0012f,0xf70098,

	0xf80152,0xfe016e,0x110012e,0x111012d,0x126013b,0x127013a,0x131013e,0x1320025,

	0x1330023,0x1380158,0x13f0029,0x1400027,0x1410147,0x1420146,0x1490035,0x14a014e,

	0x14b014d,0x152002f,0x153002d,0x1660161,0x1670160,0x17f015d,0x1920135,0x2c60087,

	0x2c70088,0x2c90089,0x2d80046,0x2d9004c,0x2da0048,0x2db004e,0x2dd004b,0x30000fe,

	0x30100fd,0x3020100,0x3030105,0x3040109,0x30600ff,0x3070106,0x3080103,0x30a0102,

	0x30b0104,0x30c0101,0x30d010a,0x3270107,0x3280108,0x3840044,0x385004a,0x3870062,

	0x3910171,0x3920173,0x3930175,0x3940177,0x3950179,0x396017b,0x397017d,0x398017f,

	0x3990181,0x39a0183,0x39b0185,0x39c0188,0x39d018a,0x39e018c,0x39f018e,0x3a00190,

	0x3a10192,0x3a30194,0x3a40196,0x3a50198,0x3a6019a,0x3a7019c,0x3a8019e,0x3a901a0,

	0x3b10170,0x3b20172,0x3b30174,0x3b40176,0x3b50178,0x3b6017a,0x3b7017c,0x3b8017e,

	0x3b90180,0x3ba0182,0x3bb0184,0x3bc0186,0x3bd0189,0x3be018b,0x3bf018d,0x3c0018f,

	0x3c10191,0x3c20193,0x3c30193,0x3c40195,0x3c50197,0x3c60199,0x3c7019b,0x3c8019d,

	0x3c9019f,0x40201ae,0x40401b2,0x40501b8,0x40601bc,0x40801be,0x40901c4,0x40a01ca,

	0x40b01d6,0x40f01e2,0x41001a2,0x41101a4,0x41201a6,0x41301a8,0x41401ac,0x41501b0,

	0x41601b4,0x41701b6,0x41801ba,0x41a01c0,0x41b01c2,0x41c01c6,0x41d01c8,0x41e01cc,

	0x41f01ce,0x42001d0,0x42101d2,0x42201d4,0x42301d8,0x42401da,0x42501dc,0x42601de,

	0x42701e0,0x42801e4,0x42901e6,0x42a01e8,0x42b01ea,0x42c01ec,0x42d01ee,0x42e01f0,

	0x42f01f2,0x43001a1,0x43101a3,0x43201a5,0x43301a7,0x43401ab,0x43501af,0x43601b3,

	0x43701b5,0x43801b9,0x43a01bf,0x43b01c1,0x43c01c5,0x43d01c7,0x43e01cb,0x43f01cd,

	0x44001cf,0x44101d1,0x44201d3,0x44301d7,0x44401d9,0x44501db,0x44601dd,0x44701df,

	0x44801e3,0x44901e5,0x44a01e7,0x44b01e9,0x44c01eb,0x44d01ed,0x44e01ef,0x44f01f1,

	0x45201ad,0x45401b1,0x45501b7,0x45601bb,0x45801bd,0x45901c3,0x45a01c9,0x45b01d5,

	0x45f01e1,0x49001aa,0x49101a9,0x20000041,0x20010041,0x20020041,0x20030041,0x20040041,

	0x20050041,0x20060041,0x20070042,0x20080041,0x20090041,0x200a0041,0x200b003f,0x200c0037,

	0x200d0037,0x200e0037,0x200f0037,0x20100054,0x20110055,0x20120056,0x20130057,0x20140058,

	0x20150059,0x20170051,0x20180064,0x20190065,0x201a0066,0x201b0067,0x201c006b,0x201d006c,

	0x201e006d,0x20200083,0x20210084,0x20220085,0x20260002,0x2028003d,0x2029003e,0x202a0037,

	0x202b0037,0x202c0037,0x202d0037,0x202e0037,0x20300082,0x20320086,0x20330005,0x20390068,

	0x203a0069,0x203c0000,0x203e0050,0x2044007d,0x207f014c,0x20a30110,0x20a40111,0x20a70112,

	0x20ac0113,0x2105001c,0x21130144,0x2116002b,0x21220033,0x212601a0,0x212e0114,0x215b000d,

	0x215c0013,0x215d0016,0x215e0019,0x2190008b,0x2191008d,0x2192008c,0x2193008e,0x2194008f,

	0x21950090,0x21a80091,0x22020092,0x22060093,0x220f0094,0x22110095,0x221200a1,0x221500a2,

	0x221900a3,0x221a00a4,0x221e00a5,0x221f00a6,0x222900a7,0x222b00a8,0x224800a9,0x226100aa,

	0x226400ab,0x226500ac,0x230200ad,0x231000ae,0x232000af,0x232100b0,0x250000b1,0x250200b2,

	0x250c00b3,0x251000b4,0x251400b5,0x251800b6,0x251c00b7,0x252400b8,0x252c00b9,0x253400ba,

	0x253c00bb,0x255000bc,0x255100bd,0x255200be,0x255300bf,0x255400c0,0x255500c1,0x255600c2,

	0x255700c3,0x255800c4,0x255900c5,0x255a00c6,0x255b00c7,0x255c00c8,0x255d00c9,0x255e00ca,

	0x255f00cb,0x256000cc,0x256100cd,0x256200ce,0x256300cf,0x256400d0,0x256500d1,0x256600d2,

	0x256700d3,0x256800d4,0x256900d5,0x256a00d6,0x256b00d7,0x256c00d8,0x258000d9,0x258400da,

	0x258800db,0x258c00dc,0x259000dd,0x259100de,0x259200df,0x259300e0,0x25a000e1,0x25a100e2,

	0x25aa00e3,0x25ab00e4,0x25ac00e5,0x25b200e6,0x25ba00e7,0x25bc00e8,0x25c400e9,0x25ca00ea,

	0x25cb00eb,0x25cf00ec,0x25d800ed,0x25d900ee,0x25e600ef,0x263a00f0,0x263b00f1,0x263c00f2,

	0x264000f3,0x264200f4,0x266000f5,0x266300f6,0x266500f7,0x266600f8,0x266a00f9,0x266b00fa,

	0xfb01001f,0xfb020021,0xfeff0037,0xfffc00fb,0xfffd00fc,

	};

static const TCollationKeyTable TheStandardTable = 

	{ TheKey, TheIndex, 517, NULL, NULL, 0 };

const TCollationKeyTable* StandardCollationMethod()

	{

	return &TheStandardTable;

	};

inline void Increment(TUint16 const *& aPointer,TBool aNarrow)

	{

	aPointer =  aNarrow ? (const TUint16*)(((const TUint8*)aPointer) + 1) : aPointer + 1;

	}

/////////////////////////////////////////////////////////////////////////////////////////////////

// TCollationValueIterator

/////////////////////////////////////////////////////////////////////////////////////////////////

/**

Initializes TCollationValueIterator object with a new character sequence.

@param aSourceIt An iterator used to access the input character (non-normalized or 

                 normalized) sequence.

@internalComponent

*/

void TCollationValueIterator::SetSourceIt(TUTF32Iterator& aSourceIt)

	{

    iCurrentKeyPos = 0;

	iKey.iKeys = 0;

    iDecompStrIt.Set(aSourceIt);

	}

/**

Gets current raw key.

Note: the method may move the iterator one or more positions forward if there are no produced

      collation keys.

@param aKey A reference to a TCollationKey object, initialized with the

            current collation key after the call, if there is available key.

@return ETrue Successfull call, aKey initialized with the current collation key,

        EFalse - the iteration has come to the end.

@internalComponent

*/

TBool TCollationValueIterator::GetCurrentKey(TCollationKey& aKey)

	{

    ASSERT(iCurrentKeyPos <= iKey.iKeys);

	if(!ProduceCollationKeys())

        {

        return EFalse;

        }

	aKey = iKey.iKey[iCurrentKeyPos];

	return ETrue;

	}

/**

Gets current key at the specified level.

Note: the method may move the iterator one or more positions forward if there are no produced

      collation keys.

@param aLevel Desired level of the collation key: 0..3

@param aKey A reference to TUint32 where the retrieved key will be stored.

@return ETrue Success, EFalse - end of the iteration.

@internalComponent

*/

TBool TCollationValueIterator::GetCurrentKey(TInt aLevel, TUint32& aKey)

	{

	TCollationKey rawKey;

	if(GetCurrentKey(rawKey))

        {

	    //Key values are ignored if their ignore bit is set and the level is less than 3: in other words, the

	    //actual Unicode value is never ignored. This does NOT conform to the system of alternate weightings

	    //described in Unicode Technical Report 10, and will probably have to be changed.

        aKey = (aLevel < 3 && (rawKey.iLow & TCollationKeyTable::EIgnoreFlag) && !IgnoringNone()) ? 0 : rawKey.Level(aLevel);

        return ETrue;

        }

    return EFalse;

	}

/**

The method iterates through the controlled character sequence and tries to find first non-zero

corresponding collation key at the specified level.

@param aLevel Desired level of the collation key: 0..3

@return Non-zero collation key value or 0 if the iteration has come to the end.

@internalComponent

*/

TUint32 TCollationValueIterator::GetNextNonZeroKey(TInt aLevel)

	{

    TUint32 key = 0;

	while(GetCurrentKey(aLevel, key) && key == 0)

		{

		Increment();

		}

	return key;

	}

/**

The method determines wheter the specified as a parameter character matches current iterator's

character.

If there is a match, the iterator will be moved one position forward.

Note: the method may move the iterator one or more positions forward if there are no produced

      collation keys.

@param aMatch The character to compare with the current iterator's character.

@return ETrue The characters match, EFalse otherwise (or the iteration has come to the end).

@internalComponent

*/

TBool TCollationValueIterator::MatchChar(TChar aMatch)

	{

    TUint32 key;

    if(GetCurrentKey(3, key))

        {

	    // Find a match for the quaternary key.. will probably be the unicode value

	    // This is a bit poor.

	    if(aMatch == key)

		    {

		    Increment();

		    return ETrue;

		    }

        }

	return EFalse;

	}

/**

Note: the method may move the iterator one or more positions forward if there are no produced

      collation keys.

@return The method returns ETrue if the iterator is at a combining character, EFalse otherwise

        (or the iterator has come to the end)

@internalComponent

*/

TBool TCollationValueIterator::AtCombiningCharacter()

	{

	TCollationKey rawKey;

	if(!GetCurrentKey(rawKey))

        {

		return EFalse;		// iteration ended

        }

	return rawKey.IsStarter() ? (TBool)EFalse : (TBool)ETrue;

	}

/**

Skips the following combining characters if they are.

Note: the method may move the iterator one or more positions forward.

@return The number of skipped combining characters.

@internalComponent

*/

TInt TCollationValueIterator::SkipCombiningCharacters()

	{

	TInt count;

	for(count=0;AtCombiningCharacter();++count)

        {

		Increment();

        }

	return count;

	}

/**

Moves the iterator one step forward making the next collation key available for getting

using GetCurrentKey().

@return ETrue Successfull call, there is a collation key available.

        EFalse - the iteration has come to the end.

@internalComponent

@see TCollationValueIterator::GetCurrentKey()

*/

TBool TCollationValueIterator::Increment()

	{

	ASSERT(iCurrentKeyPos <= iKey.iKeys);

	if(!ProduceCollationKeys())

        {

        return EFalse;

        }

	++iCurrentKeyPos;

	return ETrue;

	}

/**

Returns the position in the underlying string of the iteration,

if this is well defined. It is not well defined if either we are

half way through keys defined as a string in the collation table

or if we are half way through a canonically reordered sequence.

@return The position in the underlying string if this is well

	defined, or 0 if it is not.

*/

const TText16* TCollationValueIterator::CurrentPositionIfAtCharacter()

	{

	if (!ProduceCollationKeys())

		return iCurrentPosition;

	return iCurrentKeyPos == 0? iCurrentPosition : 0;

	}

/**

Produces the longest possible collation keys sequence using the decomposed character sequence,

pointed by iDecompStrIt iterator. But this will happen only if all keys from iKey array are 

consumed.

@return ETrue Successfull call, iKey initialized with the produced collation keys sequence,

        EFalse - the iteration has come to the end.

@internalComponent

*/

TBool TCollationValueIterator::ProduceCollationKeys()

	{

    //iKey.iKeys represents the keys count in iKey array, so load more keys, only if all 

    //collation keys are already consumed.

    if(iCurrentKeyPos == iKey.iKeys)

        {

		iCurrentPosition = iDecompStrIt.CurrentPositionIfAtCharacter();

		if(iDecompStrIt.AtEnd())

            {//No more characters in the input decomposed canonical string

			return EFalse;

            }

        //Try to get the next collation key sequence. There should be at least one key.

		GetNextRawKeySequence();

	    ASSERT(iKey.iKeys > 0);

        iCurrentKeyPos = 0;

        }

	return ETrue;

	}

/**

Consume zero or more characters from the input and convert them into zero or more collation keys.

@internalComponent

*/

void TCollationValueIterator::GetNextRawKeySequence()

	{

    //Store the first character combining class type for later use.

    TChar firstChar = iDecompStrIt.Get(0);

    TBool combining = !::IsBaseCharacter(firstChar);

	// Initialise.

	iKey.iCharactersConsumed = 0;

	iKey.iKeys = 0;

	// See if the override table has a key for the current collation unit.

	if(iMethod.iOverrideTable)

        {

		GetKeyFromTable(iMethod.iOverrideTable);

        }