/*

 * 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 "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: 

 *

 */

 #include <e32std.h>

 #include <convdata.h>

 #define ARRAY_LENGTH(aArray) (sizeof(aArray)/sizeof((aArray)[0]))

 LOCAL_D const SCnvConversionData::SVariableByteData::SRange asciiVariableByteDataRanges[]=

 	{

 		{

 		0x00,

 		0xff,

 		0,

 		0

 		}

 	};

 LOCAL_D const SCnvConversionData::SOneDirectionData::SRange asciiToUnicodeDataRanges[]=

 	{

 		{

 		0x00,

 		0x7f,

 		SCnvConversionData::SOneDirectionData::SRange::EDirect,

 		0,

 		0,

 			{

 			0,

 			0

 			}

 		}

 	};

 LOCAL_D const SCnvConversionData::SOneDirectionData::SRange unicodeToAsciiDataRanges[]=

 	{

 		{

 		0x0000,

 		0x007f,

 		SCnvConversionData::SOneDirectionData::SRange::EDirect,

 		1,

 		0,

 			{

 			0,

 			0

 			}

 		}

 	};

 GLREF_D const SCnvConversionData asciiConversionData=

 	{

 	SCnvConversionData::EUnspecified,

 		{

 		ARRAY_LENGTH(asciiVariableByteDataRanges),

 		asciiVariableByteDataRanges

 		},

 		{

 		ARRAY_LENGTH(asciiToUnicodeDataRanges),

 		asciiToUnicodeDataRanges

 		},

 		{

 		ARRAY_LENGTH(unicodeToAsciiDataRanges),

 		unicodeToAsciiDataRanges

 		},

 	NULL,

 	NULL

 	};

 GLREF_C void IsCharacterSetAscii(TInt& aConfidenceLevel, const TDesC8& aSample)

 	{

 	// loop through the aSample text checking the range of the character

 	// If greater than 127 then it's not ASCII (gotta be harsh!)  ... 

 	TInt sampleLength = aSample.Length();

 	if (sampleLength == 0)

 		{

 		aConfidenceLevel = 91;

 		return;

 		}

 	aConfidenceLevel = 100;

 	_LIT8(KAsciiEsc,"\x28\x42");

 	_LIT8(KJisRomanEsc,"\x28\x4a");

 	_LIT8(KJisCEsc,"\x24\x40");

 	_LIT8(KJisX0208Esc,"\x24\x42");

 	_LIT8(KJisX0212Esc,"\x24\x28\x44");

 	_LIT8(KHz1Esc,"\x7e\x7e");

 	_LIT8(KHz2Esc,"\x7e\x7b");

 	_LIT8(KHz3Esc,"\x7e\x7b");

 	TInt asciiResult = 0;

 	TInt jisRomanResult = 0; 

 	TInt jisCResult = 0;

 	TInt jisX0208Result =0;

 	TInt jisX0212Result =0;

 	TInt hz1Result=0;

 	TInt hz2Result=0;

 	TInt hz3Result=0;

 	TInt escSequences = 0; 

 	TInt controls = 0;

 	for (TInt i = 0; i < sampleLength; ++i)

 		{

 		if ((aSample[i]&0x80)!=0x00)

 			{

 			aConfidenceLevel = 0;

 			break;

 			}

 		if (i > asciiResult)

 			{

 			asciiResult=(aSample.Right(sampleLength-i)).Find(KAsciiEsc);

 			if (asciiResult!=KErrNotFound) //aConfidenceLevel-=2;

 				escSequences += 2;

 			}

 		if (i > jisRomanResult)

 			{

 			jisRomanResult=(aSample.Right(sampleLength-i)).Find(KJisRomanEsc);

 			if (jisRomanResult!=KErrNotFound) //aConfidenceLevel-=2;

 				escSequences += 2;

 			}

 		if (i > jisCResult)

 			{

 			jisCResult=(aSample.Right(sampleLength-i)).Find(KJisCEsc);

 			if (jisCResult!=KErrNotFound) //aConfidenceLevel-=2;

 				escSequences += 2;

 			}

 		if (i > jisX0208Result)

 			{

 			jisX0208Result=(aSample.Right(sampleLength-i)).Find(KJisX0208Esc);

 			if (jisX0208Result!=KErrNotFound) //aConfidenceLevel-=2;

 				escSequences += 2;

 			}

 		if (i > jisX0212Result)

 			{

 			jisX0212Result=(aSample.Right(sampleLength-i)).Find(KJisX0212Esc);

 			if (jisX0212Result!=KErrNotFound) //aConfidenceLevel-=2;

 				escSequences += 2;

 			}

 		if (i > hz1Result)

 			{

 			hz1Result=(aSample.Right(sampleLength-i)).Find(KHz1Esc);

 			if (hz1Result!=KErrNotFound) //aConfidenceLevel-=2;

 				escSequences += 2;

 			}

 		if (i > hz2Result)

 			{

 			hz2Result=(aSample.Right(sampleLength-i)).Find(KHz2Esc);

 			if (hz2Result!=KErrNotFound) //aConfidenceLevel-=2;

 				escSequences += 2;

 			}

 		if (i > hz3Result)

 			{

 			hz3Result=(aSample.Right(sampleLength-i)).Find(KHz3Esc);

 			if (hz3Result!=KErrNotFound) //aConfidenceLevel-=2;

 				escSequences += 2;

 			}

 		if (aSample[i]==0x7f)

 			// 0x7f is the control code for delete ... 

 			{

 			aConfidenceLevel = 0;

 			break;

 			}

 		 if (aSample[i]==0x1b)

 			{

 			static const TInt smsExtensionTable[12] = 

 				{0x0a, 0x14, 0x1b, 0x24, 0x28, 0x29, 0x2f, 0x3c, 0x3d, 0x3e, 0x40, 0x65};

 			for (TInt j=0; j < 12; ++j) // change the hard coded number to the Array length 

 				{

 				TInt increment1 = i+1;

 				if (increment1 >= sampleLength)

 					break;

 				if (aSample[increment1] == smsExtensionTable[j])

 					{

 					aConfidenceLevel-=5;

 					// /x1b/x24 & /x1b/x28 are the first two characters of a few

 					// of  JIS & ISO2022JP escape sequence (That's why 0x24 was added in smsExtensionTable)

 					// So if what's up next matches any JIS & IS02022JP escape sequence..... more deduction 

 					// of the confidence Level 

 					TInt increment2 = i+2;

 					TInt increment3 = i+3;

 					if((increment2 >= sampleLength)||((increment3) >= sampleLength))

 						break;

 					if (smsExtensionTable[j]==0x24)

 						{

 						// 24 -> 40,42 (28,44)

 						if ((aSample[increment2]==0x40) || (aSample[increment2]==0x42) ||

 							((aSample[increment2]==0x28)&&(aSample[increment3]==0x44)))

 							{

 							aConfidenceLevel=0;

 							break;

 							}

 						}

 					else if (smsExtensionTable[j]==0x28)

 						{

 						// 28 -> 42, 49, 4a

 						if ((aSample[increment2]==0x42) || (aSample[increment2]==0x49) || (aSample[increment2]==0x4a))

 							{

 							aConfidenceLevel=0;

 							break;

 							}

 						}

 					}

 				}

 			if(aConfidenceLevel==0)

 				break;

 			}

 			if (controls < 100 && aSample[i] < 0x20 && 	aSample[i] != '\r' && aSample[i] != '\n' && aSample[i] != '\t')

 			// a few more control codes besides LF, CR, TAB 

 			{

 			controls ? controls *= 3 : controls = 3; 

 			}

 		}

 	aConfidenceLevel -= controls;

 	aConfidenceLevel = aConfidenceLevel - ((escSequences*100)/sampleLength);

 	aConfidenceLevel =(aConfidenceLevel >0)? aConfidenceLevel: 0;

 	}