/*

* 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;

	}