// 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:

 // This file contains an implementation of the ToneGenerator interface

 // that converts all tone generation requests in to sampled audio 

 // data to be played through the normal local sampled audio interface

 // 

 //

 #include "BtToneGenerator.h"

 #include <e32math.h>

 #include <mda/common/resource.h>

 /******************************************************************************

 *	Tone Generators

 *

 *	The following classes are used to generate simple frequency/duration tones,

 *	DTMF, and SymbianOS tone sequences in a WINS environment.  The below code

 *	should only be considered for WINS.

 ******************************************************************************/

 // this defines the maximum possible amplitude allowed for TSineGen::SetFrequency()

 const TInt KMaxAmplitude = 0x8000;

 // default number of samples for trailing silence following a Tone

 const TInt KDefaultTrailingSilenceSamples = 20;

 //

 // Sine tone generator

 //

 const TInt16 TSineGen::SineTable[KMaxSineTable] =

 	{

 		 0,   804,  1607,  2410,  3211,  4011,  4807,  5601,

 	  6392,  7179,  7961,  8739,  9511, 10278, 11038, 11792,

 	 12539, 13278, 14009, 14732, 15446, 16150, 16845, 17530,

 	 18204, 18867, 19519, 20159, 20787, 21402, 22004, 22594,

 	 23169, 23731, 24278, 24811, 25329, 25831, 26318, 26789,

 	 27244, 27683, 28105, 28510, 28897, 29268, 29621, 29955,

 	 30272, 30571, 30851, 31113, 31356, 31580, 31785, 31970,

 	 32137, 32284, 32412, 32520, 32609, 32678, 32727, 32757,

 	 32767, 32757, 32727, 32678, 32609, 32520, 32412, 32284,

 	 32137, 31970, 31785, 31580, 31356, 31113, 30851, 30571,

 	 30272, 29955, 29621, 29268, 28897, 28510, 28105, 27683,

 	 27244, 26789, 26318, 25831, 25329, 24811, 24278, 23731,

 	 23169, 22594, 22004, 21402, 20787, 20159, 19519, 18867,

 	 18204, 17530, 16845, 16150, 15446, 14732, 14009, 13278,

 	 12539, 11792, 11038, 10278,  9511,  8739,  7961,  7179,

 	  6392,  5601,  4807,  4011,  3211,  2410,  1607,   804,

 		 0,  -804, -1607, -2410, -3211, -4011, -4807, -5601,

 	 -6392, -7179, -7961, -8739, -9511,-10278,-11038,-11792,

 	-12539,-13278,-14009,-14732,-15446,-16150,-16845,-17530,

 	-18204,-18867,-19519,-20159,-20787,-21402,-22004,-22594,

 	-23169,-23731,-24278,-24811,-25329,-25831,-26318,-26789,

 	-27244,-27683,-28105,-28510,-28897,-29268,-29621,-29955,

 	-30272,-30571,-30851,-31113,-31356,-31580,-31785,-31970,

 	-32137,-32284,-32412,-32520,-32609,-32678,-32727,-32757,

 	-32767,-32757,-32727,-32678,-32609,-32520,-32412,-32284,

 	-32137,-31970,-31785,-31580,-31356,-31113,-30851,-30571,

 	-30272,-29955,-29621,-29268,-28897,-28510,-28105,-27683,

 	-27244,-26789,-26318,-25831,-25329,-24811,-24278,-23731,

 	-23169,-22594,-22004,-21402,-20787,-20159,-19519,-18867,

 	-18204,-17530,-16845,-16150,-15446,-14732,-14009,-13278,

 	-12539,-11792,-11038,-10278, -9511, -8739, -7961, -7179,

 	 -6392, -5601, -4807, -4011, -3211, -2410, -1607,  -804,

 	};

 const TInt16 TSineGen::IncTable[KMaxSineTable] =

 	{

 			804,  803,  803,  801,  800,  796,  794,

 	  791,  787,  782,  778,  772,  767,  760,  754,

 	  747,  739,  731,  723,  714,  704,  695,  685,

 	  674,  663,  652,  640,  628,  615,  602,  590,

 	  575,  562,  547,  533,  518,  502,  487,  471,

 	  455,  439,  422,  405,  387,  371,  353,  334,

 	  317,  299,  280,  262,  243,  224,  205,  185,

 	  167,  147,  128,  108,   89,   69,   49,   30,

 	   10,  -10,  -30,  -49,  -69,  -89, -108, -128,

 	 -147, -167, -185, -205, -224, -243, -262, -280,

 	 -299, -317, -334, -353, -371, -387, -405, -422,

 	 -439, -455, -471, -487, -502, -518, -533, -547,

 	 -562, -575, -590, -602, -615, -628, -640, -652,

 	 -663, -674, -685, -695, -704, -714, -723, -731,

 	 -739, -747, -754, -760, -767, -772, -778, -782,

 	 -787, -791, -794, -796, -800, -801, -803, -803,

 	 -804, -804, -803, -803, -801, -800, -796, -794,

 	 -791, -787, -782, -778, -772, -767, -760, -754,

 	 -747, -739, -731, -723, -714, -704, -695, -685,

 	 -674, -663, -652, -640, -628, -615, -602, -590,

 	 -575, -562, -547, -533, -518, -502, -487, -471,

 	 -455, -439, -422, -405, -387, -371, -353, -334,

 	 -317, -299, -280, -262, -243, -224, -205, -185,

 	 -167, -147, -128, -108,  -89,  -69,  -49,  -30,

 	  -10,   10,   30,   49,   69,   89,  108,  128,

 	  147,  167,  185,  205,  224,  243,  262,  280,

 	  299,  317,  334,  353,  371,  387,  405,  422,

 	  439,  455,  471,  487,  502,  518,  533,  547,

 	  562,  575,  590,  602,  615,  628,  640,  652,

 	  663,  674,  685,  695,  704,  714,  723,  731,

 	  739,  747,  754,  760,  767,  772,  778,  782,

 	  787,  791,  794,  796,  800,  801,  803,  803,

 	  804

 	};

 void TSineGen::SetFrequency(TInt aFrequency,TInt aAmplitude)

 //

 // Given the frequency set iStep.

 // Reset iPosition to the equivalent of 0 degrees.

 // In the special case of aFrequency==4KHz set iPosition to 90 degrees.

 //

 	{

 	if (aAmplitude>(1<<15))

 		iAmplitude=(1<<15);

 	else if (aAmplitude<-(1<<15))

 		iAmplitude=-(1<<15);

 	else

 		iAmplitude=aAmplitude;

 //

 // There are 256 entries in the sine table to traverse 360 degrees.

 // The codec requires samples at a rate of 8000 per second.

 // Thus for a 1Hz tone the step will be 256/8000 or 4/125.

 // Now we need need the integer part of the result to end up in

 // the MSB so we need to multiply by 2^24. This gives the formula

 // step = (f*4*2^24)/125 or (f*2^26)/125.

 // Our highest frequency is 4KHz so that the term (f*2^26) exceeds

 // a 32 bit result by 4000/2^6 (2^6 is the number of significant bits

 // left after a multiply by 2^26). i.e. 6 bits. We overcome this by

 // having 6 bits less in the fraction, so the new formula becomes

 // ((f*2^20)/125)*2^6. This still gives us 20 significant bits in the

 // fraction.

 //

 	iStep=(((TUint)aFrequency<<20)/125)<<6;

 	iPosition=(aFrequency==4000 ? 0x40000000 : 0);

 	}

 TInt TSineGen::NextSample()

 //

 // Generate the next sample using linear interpolation

 //

 	{

 	TUint pos=iPosition>>24;

 	TInt amp=((IncTable[pos]*((iPosition&0x00ffffff)>>20)));

 	amp>>=4;

 	amp+=SineTable[pos];

 	amp=(amp*iAmplitude)>>15;

 	iPosition+=iStep;

 	return(amp);

 	}

 void TSineWave::Generate(TInt16* aDest,TInt aCount)

 //

 // Called when more samples need to be generated.

 //

 	{

 	while (aCount--)

 		{

 		*aDest++=STATIC_CAST(TInt16,iGen1.NextSample()+iGen2.NextSample());

 		}

 	}

 void TSineWave::SetFrequency(TInt aFrequency,TInt aAmplitude)

 //

 // Set to generate a single frequency

 //

 	{

 	SetFrequency(aFrequency,aAmplitude,0,0);

 	}

 void TSineWave::SetFrequency(TInt aFrequency1,TInt aAmplitude1,TInt aFrequency2,TInt aAmplitude2)

 //

 // Set to generate two frequencies

 //

 	{

 	iGen1.SetFrequency(aFrequency1,aAmplitude1);

 	iGen2.SetFrequency(aFrequency2,aAmplitude2);

 	}

 //

 // TMdaToneGenerator

 //

 void TMdaToneGenerator::Configure(TInt aRate, TInt aChannels, TInt aRepeats, TInt aSilence, TInt aRampUp)

 //

 // Set up this tone generator to generate data at the desired sample rate

 // and number of channels (typically mono/stereo)

 // 

 	{

 	iRate = aRate;

 	iChannels = aChannels;

 	iSamplesLeft = 0;

 	iRampUp = ETrue; // Default ramping to on as it is normally useful

 	iRampDown = ETrue;

 	iRepeats = aRepeats;

 	iSilenceBetweenRepeats = aSilence;

 	iRampUpCount = aRampUp;

 	iRampUpLeft = aRampUp;

 	iAfterRepeatSilence = EFalse;

 	}

 LOCAL_C void RampVolume(TInt16* aData,TInt aCount,TInt aStartVol,TInt aEndVol)

 //

 // Simple function to ramp down the volume of some samples 

 // Typically used to prevent "clicking" artifacts at the beginning/end of tones

 //

 	{

 	TInt step = (aEndVol - aStartVol)/aCount;

 	while (aCount--)

 		{

 		TInt data = TInt(*aData) * aStartVol;

 		*aData++ = TInt16(data>>15);

 		aStartVol += step;

 		}

 	}

 TInt TMdaToneGenerator::FillBuffer(TDes8& aBuffer)

 //

 // Fill the supplied buffer with tone data

 // Sets the buffer length to zero if there is no more data to play

 // The buffer must have a max length of at least one sample * channels

 // e.g. 2 bytes mono, 4 bytes stereo

 //

 	{

 	ASSERT(aBuffer.MaxLength()>= (iChannels<<1));

 	aBuffer.SetMax();

 	TBool silence;

 	TInt samples = 0; // 

 	TInt used = 0; // Data used

 	TInt avail = aBuffer.Length(); // Data filled

 	TInt count = 0; // Data to be converted

 	TBool rampUp = EFalse;

 	TMdaPtr8 fill;

 	fill.Set(aBuffer); // Pointer to data left to be filled

 	// 

 	// The rest of this function will loop around continually until the buffer

 	// is filled or there is no more data to play

 	//

 Restart:

 	silence = EFalse; // Reset

 	if (iSamplesLeft == 0)

 		{

 		if (iTrailingSilence == 0)

 			{

 			TInt error = GetNextTone();

 			if (error)

 				return error;

 			rampUp = ETrue;

 			if ((iSamplesLeft==0)&&(iTrailingSilence==0))

 				{ 

 				if ((iSilenceBetweenRepeats)&&(!iAfterRepeatSilence))

 					{

 					iTrailingSilence = iSilenceBetweenRepeats;

 					iAfterRepeatSilence = ETrue;

 					goto Restart;

 					}

 				else

 					{

 					if ((iRepeats>0)||(iRepeats==KMdaRepeatForever))

 						{

 						iAfterRepeatSilence = EFalse;

 						if (iRepeats>0)

 							iRepeats--;

 						Reset();

 						goto Restart;

 						}

 					}

 				// No more to play

 				goto Finished;

 				}

 			goto Restart;

 			}

 		else

 			{

 			silence = ETrue;

 			samples = iTrailingSilence;

 			}

 		}

 	else

 		samples = iSamplesLeft;

 	count = Min(samples,avail>>1);

 	fill.SetLength(count<<1);

 	if (!silence)

 		{ // Generate wave

 		iSineWave.Generate(REINTERPRET_CAST(TInt16*,&fill[0]),count);

 		if (iRampUp)

 			{ // Ramp up volume at beginning of tone

 			const TInt KRampUpSamples = 50;

 			if (rampUp)

 				{ // Fade in first few samples

 				TInt fadeInLength = Min(Min(KRampUpSamples,iSamplesLeft),(fill.Length()>>1));

 				RampVolume(CONST_CAST(TInt16*,REINTERPRET_CAST(const TInt16*,(&fill[0]))),fadeInLength,0,1<<15);

 				}

 			}

 		if (iRampDown)

 			{ // Ramp down volume at end of tone

 			const TInt KRampDownSamples = 50;

 			if ((iSamplesLeft-count) < KRampDownSamples)

 				{ // Fade out last few samples

 				TInt fadeOutLength = Min(Min(KRampDownSamples,iSamplesLeft),(fill.Length()>>1));

 				RampVolume(CONST_CAST(TInt16*,REINTERPRET_CAST(const TInt16*,(&(fill.Right(fadeOutLength<<1))[0]))),fadeOutLength,1<<15,0);

 				}

 			}

 		iSamplesLeft -= count;

 		}

 	else

 		{ // Generate silence

 		fill.FillZ(count<<1);

 		iTrailingSilence -= count;

 		}

 	used += count<<1;

 	avail -= count<<1;

 	fill.Shift(count<<1);

 	if (avail>(iChannels<<1))

 		goto Restart;

 Finished:

 	aBuffer.SetLength(used);

 	// Do any ramp up that is required

 	if (iRampUpLeft>0)

 		{

 		TInt words = iRampUpLeft * iChannels;

 		words = Min(words,used>>1);

 		if (words>0) // In case buffer has zero length...

 			{

 			TInt left = iRampUpLeft * iChannels;

 			TInt rampup = iRampUpCount * iChannels;

 			iRampUpLeft -= words/iChannels;

 			TInt16* sample = REINTERPRET_CAST(TInt16*,&aBuffer[0]);

 			while (words--)

 				{

 				*sample++ = STATIC_CAST(TInt16,(TInt32(*sample)*(rampup-(left--)))/rampup);

 				}

 			}

 		}

 	return KErrNone;

 	}

 TInt TMdaToneGenerator::DurationToSamples(const TTimeIntervalMicroSeconds& aDuration)

 //

 // Convert the given duration to a sample count using the current settings

 //

 	{

 	const TInt64 KTInt64OneMilion = 1000000;

 	// Calculate duration as samples

 	TInt64 microSeconds(aDuration.Int64());  // MSVC doesn't like "aDuration.Int64()" in line below

 	TInt64 dur = ((TInt64(iRate) * TInt64(iChannels) * microSeconds) / KTInt64OneMilion);

 	if (I64HIGH(dur)>0)

 		return KMaxTInt; // Ridiculous!

 	else

 		return I64LOW(dur);

 	}

 //

 // TMdaSimpleToneGenerator

 //

 void TMdaSimpleToneGenerator::Reset()

 	{

 	iPlayed = EFalse;

 	}

 void TMdaSimpleToneGenerator::SetFrequencyAndDuration(TInt aFrequency, const TTimeIntervalMicroSeconds& aDuration)

 //

 // Store the frequency and duration of the specified sine tone

 //

 	{

 	iFrequency = aFrequency;

 	iDuration = aDuration;

 	iPlayed = EFalse;

 	}

 TInt TMdaSimpleToneGenerator::GetNextTone()

 //

 // Simple implementation - just sets the supplied frequency and duration

 //

 	{

 	// This class only plays one tone for the specified duration

 	if (!iPlayed)

 		{

 		iSamplesLeft = I64LOW((iDuration.Int64() * TInt64(iRate))/1000000);

 		iSineWave.SetFrequency(iFrequency,1<<14);

 		iPlayed = ETrue;

 		iTrailingSilence = 20; // Just to stop clicking

 		}

 	return KErrNone;

 	}

 //

 // TMdaDualToneGenerator

 //

 void TMdaDualToneGenerator::Reset()

 	{

 	iPlayed = EFalse;

 	}

 void TMdaDualToneGenerator::SetFrequencyAndDuration(TInt aFrequencyOne, TInt aFrequencyTwo, const TTimeIntervalMicroSeconds& aDuration)

 	{

 	// Store the frequencies and duration of the specified dual tone

 	iFrequencyOne = aFrequencyOne;

 	iFrequencyTwo = aFrequencyTwo;

 	iDuration = aDuration;

 	iPlayed = EFalse;

 	}

 // 

 // This is called by TMdaToneGenerator::FillBuffer() 

 // to calculate the number of samples (iSamplesLeft) that will be needed 

 // for the tone to be played and to initialize the sine wave generator.

 // If the tone has already been played, then leaves iSamplesLeft 

 // unmodified (should be zero) to indicate that it has finished.

 //

 TInt TMdaDualToneGenerator::GetNextTone()

 	{

 	// This class only plays one tone for the specified duration

 	if (!iPlayed)

 		{

 		iSamplesLeft = I64LOW((iDuration.Int64() * TInt64(iRate))/KOneMillionMicroSeconds);

 		iSineWave.SetFrequency(iFrequencyOne, KMaxAmplitude/2, iFrequencyTwo, KMaxAmplitude/2);

 		iPlayed = ETrue;

 		iTrailingSilence = KDefaultTrailingSilenceSamples; // Just to stop clicking

 		}

 	return KErrNone;

 	}

 //

 // TMdaDTMFGenerator

 //

 const TInt KRecalculateToneLengths = KMinTInt;

 void TMdaDTMFGenerator::Reset()

 	{

 	iChar = 0;

 	}

 void TMdaDTMFGenerator::SetToneDurations(const TTimeIntervalMicroSeconds32 aOn,

 							const TTimeIntervalMicroSeconds32 aOff,

 							const TTimeIntervalMicroSeconds32 aPause)

 //

 // Setup the DTMF tone durations

 // aOn can be == -1 indicating should play first tone indefinately

 //

 	{

 	ASSERT(aOn.Int() >=-1);

 	ASSERT(aOff.Int()>=0);

 	ASSERT(aPause.Int()>=0);

 	iOn = aOn;

 	iOff = aOff;

 	iPause = aPause;

 	iOnSamples = KRecalculateToneLengths; // Must recalculate these later

 	}

 void TMdaDTMFGenerator::SetString(const TDesC& aDTMFString)

 //

 // Store the DTMF string to be played

 // No need to validate it as it will already have been checked 

 //

 	{

 	iChar = 0;

 	iDTMFString = &aDTMFString;

 	}

 const TUint8 KDtmfVolumeTable[4][4]=

 //

 // Relative strengths to assign to different DTMF tones

 //

 // This is only important if DTMFs are being played through a speaker

 // and need to be machine-recognisable. This table compensates for frequency

 // drop-off in the speaker and can boost the relative volume of some 

 // frequencies so they are still within tolerance.

 // 

 // The values normally need to be determined using a frequency analyser on 

 // the hardware

 // 

 // Each column == same low frequency (697, 770, 852, 941 Hz)

 // Each row == same high frequency (1209, 1336, 1477, 1633 Hz)

 //

 // The value are interpreted as ratios:

 //		0  == 100% low

 //		7f == 50% low, 50% high

 //		ff == 100% high

 //

 	{

 	{38,27,29,37},

 	{46,36,36,46},

 	{62,47,49,58},

 	{70,56,60,68}

 	};

 const TUint8 KDtmfTone697=0x0;

 const TUint8 KDtmfTone770=0x1;

 const TUint8 KDtmfTone852=0x2;

 const TUint8 KDtmfTone941=0x3;

 const TUint8 KDtmfTone1209=0x00;

 const TUint8 KDtmfTone1336=0x10;

 const TUint8 KDtmfTone1477=0x20;

 const TUint8 KDtmfTone1633=0x30;

 const TUint8 KDtmfToneTable[16]=

 	{

 	KDtmfTone941|KDtmfTone1336,//0

 	KDtmfTone697|KDtmfTone1209,//1

 	KDtmfTone697|KDtmfTone1336,//2

 	KDtmfTone697|KDtmfTone1477,//3

 	KDtmfTone770|KDtmfTone1209,//4

 	KDtmfTone770|KDtmfTone1336,//5

 	KDtmfTone770|KDtmfTone1477,//6

 	KDtmfTone852|KDtmfTone1209,//7

 	KDtmfTone852|KDtmfTone1336,//8

 	KDtmfTone852|KDtmfTone1477,//9

 	KDtmfTone697|KDtmfTone1633,//A

 	KDtmfTone770|KDtmfTone1633,//B

 	KDtmfTone852|KDtmfTone1633,//C

 	KDtmfTone941|KDtmfTone1633,//D

 	KDtmfTone941|KDtmfTone1209,//E or *

 	KDtmfTone941|KDtmfTone1477,//F or #

 	};

 TInt TMdaDTMFGenerator::GetNextTone()

 //

 // Setup frequency/duration/silence settings for next DTMF tone

 // Supported characters are 0-9 A-F * # , and any kind of white space

 //

 	{

 	TBool onlyPlayFirstTone = EFalse;

 	if (iOnSamples == KRecalculateToneLengths)

 		{

 		// Must recalculate tone durations as samples

 		// Handle special case where tone on duration negative

 		// - meaning play first character indefinately

 		if (iOn.Int()>=0)

 			iOnSamples = DurationToSamples(TInt64(iOn.Int()));

 		else 

 			{

 			onlyPlayFirstTone = ETrue;

 			iOnSamples = -1; 

 			}

 		iOffSamples = DurationToSamples(TInt64(iOff.Int()));

 		iPauseSamples = DurationToSamples(TInt64(iPause.Int()));

 		}

 	ASSERT(iDTMFString);

 	if (iChar==iDTMFString->Length())

 		return KErrNone; // Finished. Nothing to do

 	TInt highFrequency = 0;

 	TInt highVolume = 0;

 	TInt lowFrequency = 0; 

 	TInt lowVolume =0;

 Retry:

    	TChar c((*iDTMFString)[iChar++]);

    	if ((TUint)c=='#' || (TUint)c=='*' || c.IsHexDigit())

    		{

     	TInt tableIndex;

 		switch ((TUint)c)

 			{

 		case '*':

 			tableIndex=14;

 			break;

 		case '#':

 			tableIndex=15;

 			break;

 		default:

 			if (c.IsDigit())

     			tableIndex=(TUint)c-'0';

 			else //letter

 		   		{

 				c.UpperCase();

     			tableIndex=(TUint)c-'A'+10;

 				}

 			}

 		TInt high=KDtmfToneTable[tableIndex]&0xf0;

 		TInt low=KDtmfToneTable[tableIndex]&0x0f;

 		switch(high)

 			{

 		case KDtmfTone1209:

 			highFrequency=1209;

 			break;

 		case KDtmfTone1336:

 			highFrequency=1336;

 			break;

 		case KDtmfTone1477:

 			highFrequency=1477;

 			break;

 		default://KDtmfTone1633:

 			highFrequency=1633;

 			break;

 			}

 		switch(low)

 			{

 		case KDtmfTone697:

 			lowFrequency=697;

 			break;

 		case KDtmfTone770:

 			lowFrequency=770;

 			break;

 		case KDtmfTone852:

 			lowFrequency=852;

 			break;

 		default://KDtmfTone941:

 			lowFrequency=941;

 			break;

 			}

 		high>>=4;

 		const TUint8* dtmfVolumes=&KDtmfVolumeTable[0][0];

 		TInt volume=dtmfVolumes[((low)<<2)+(high)]<<7;

 		highVolume = volume;

 		lowVolume = (1<<15)-volume;

 		iTrailingSilence = iOffSamples;

 		iSamplesLeft = iOnSamples;

 		}

    	else if ((TUint)c==',')

 		{

   		iTrailingSilence = iPauseSamples;

  		iSamplesLeft = 0;

     	}

 	else if (c.IsSpace())

 		{

 		if (iChar < iDTMFString->Length())

 			goto Retry;

 		}

 	else

 		return KErrCorrupt;

 	if (iOnSamples < 0) // Play only first character for ever

 		{

 		iTrailingSilence = 0;

 		iSamplesLeft = iRate * iChannels; // One second of samples

 		iChar = 0; // Reset so this character is played again next time

 		iRampDown = EFalse;

 		if (!onlyPlayFirstTone)

 			{

 			iRampUp = EFalse;

 			// This is not the first time around so we should not

 			// reset the tone generator - it will already have the

 			// correct settings and setting them again would cause

 			// an audible discontinuity

 			return KErrNone; 

 			}

 		}

 	iSineWave.SetFrequency(highFrequency,highVolume,lowFrequency,lowVolume);

 	return KErrNone;

 	}

 //

 // TMdaSequenceGenerator

 //

 //

 // Sequence constants

 // 

 //const TInt KMaxFixedSequenceStack=KMaxSequenceStack;//Max nesting level of FixedSequences * 2 

 #ifdef _DEBUG

 const TInt16 KFixedSequenceSignatureOne='S'+('Q'<<8); 

 const TInt16 KFixedSequenceSignatureTwo='N'+('C'<<8);

 #endif // _DEBUG

 const TInt KFixedSequenceFunctionReturn=-1;

 const TInt KFixedSequenceFunctionStartLoop=-2;

 const TInt KFixedSequenceFunctionEndLoop=-3;

 void TMdaSequenceGenerator::Reset()

 	{

 	iInstructionPtr = REINTERPRET_CAST(const TInt16*,&((*iSequenceData)[0]));

 	iInstructionPtr += 2; // Skip signature

 	iStackIndex = 0;

 	}

 void TMdaSequenceGenerator::SetSequenceData(const TDesC8& aSequenceData)

 //

 // Store the sequence data to be played

 // No need to validate it as it will already have been checked 

 //

 	{

 	iSequenceData = &aSequenceData;

 	iInstructionPtr = REINTERPRET_CAST(const TInt16*,&aSequenceData[0]);

 	iLastInstruction = iInstructionPtr + (iSequenceData->Length()>>1) - 1;

 	// These are asserts because this should not be called if signature not present

 	ASSERT(*iInstructionPtr == KFixedSequenceSignatureOne);

 	ASSERT(*(iInstructionPtr+1) == KFixedSequenceSignatureTwo);

 	iInstructionPtr += 2; // Skip signature

 	iStackIndex = 0;

 	}

 TInt TMdaSequenceGenerator::GetNextTone()

 //

 //

 	{

 	ASSERT(iInstructionPtr); // Sanity check

 	TInt ret = KRequestPending;

 	while (ret == KRequestPending)

 		{

 		if (iInstructionPtr > iLastInstruction)

 			ret = KErrCorrupt;

 		else if (*iInstructionPtr<=0)

 	   		{

 	   		switch (*iInstructionPtr)

 	   			{

 	   		case KFixedSequenceFunctionReturn: // End of sequence

 				ret = KErrNone;

 				break;

 	   		case KFixedSequenceFunctionStartLoop:

 				if (iStackIndex>2) // Validate - can only nest twice

 					ret = KErrCorrupt;

 				else if ((iInstructionPtr+2) > iLastInstruction)

 					ret = KErrCorrupt; // Don't run off end of sequence

 				else

 					{

 		   			iStack[iStackIndex++]=(TInt)(iInstructionPtr+2);

 		   			iStack[iStackIndex++]=(TInt)*(iInstructionPtr+1);

 	   				iInstructionPtr+=2;

 					}

 	   			break;

 	   		case KFixedSequenceFunctionEndLoop:

 				if (iStackIndex==0) // Validate - must already be nested

 					ret = KErrCorrupt;

 				else

 					{

 		   			if ((--iStack[iStackIndex-1])!=0)

 		   				iInstructionPtr=(TInt16*)iStack[iStackIndex-2];

 		   			else

 		   				{

 		   				iStackIndex-=2;

 		   				iInstructionPtr++;

 		   				}

 					}

 	   			break;

 	   		default: // Bad sequence

 				ret = KErrCorrupt;

 	   			}

 			}

 		else

 			{

 			if ((iInstructionPtr+5) > iLastInstruction)

 				ret = KErrCorrupt; // Don't run off end of sequence

 			else

 				{

 				iSamplesLeft = *iInstructionPtr++;

 				TInt freqOne = *iInstructionPtr++;

 				TInt volOne  = *iInstructionPtr++;

 				TInt freqTwo = *iInstructionPtr++;

 				TInt volTwo  = *iInstructionPtr++;

 				if ((volOne> 1<<15)||(volTwo > 1<<15))

 					ret = KErrCorrupt;

 				else	

 					{

 					iSineWave.SetFrequency(freqOne,volOne,freqTwo,volTwo);

 					ret = KErrNone;

 					}

 				}

 			}

 		}

 	return ret;

 	}

 // ---------------------------------

 // Code to generate sine table files used by tone generator

 // Optionally called from InitL()

 // #define GENERATE_SINE_TABLES 1

 #ifdef GENERATE_SINE_TABLES

 LOCAL_C GenerateSineTableL()

 	{

 	_LIT(KSineFile,"sine.txt");

 	_LIT(KSineIncFile,"sineinc.txt");

 	RFile file;

 	file.Replace(MdaManager::Fs(),KSineFile,EFileWrite);

 	CleanupClosePushL(file);

 	RFile file2;

 	file2.Replace(MdaManager::Fs(),KSineIncFile,EFileWrite);

 	CleanupClosePushL(file2);

 	const TReal pi=3.141592653589;

 	const TReal twopi=pi*2;

 	const TReal samples = 256.0;

 	const TReal step = twopi/samples;

 	TBuf8<128> sinebuffer;

 	TBuf8<128> incbuffer;

 	TReal res;

 	TInt first=0;

 	TInt last=KMaxTInt;

 	TInt current;

 	_LIT8(KFormat,"%6d,");

 	_LIT8(KNewLine,"\n");

 	for(TReal angle=0.0;angle<=(twopi-step);) // Copes with rounding errors

 		{

 		sinebuffer.Zero();

 		incbuffer.Zero();

 		for (int i=0;i<8;i++)

 			{

 			User::LeaveIfError(Math::Sin(res,angle));

 			current = TInt(KMaxTInt16*res);

 			sinebuffer.AppendFormat(KFormat,current);

 			if (last != KMaxTInt)

 				incbuffer.AppendFormat(KFormat,current-last);

 			else

 				first = current;

 			last = current;

 			angle += step;

 			}

 		sinebuffer.Append(KNewLine);

 		incbuffer.Append(KNewLine);

 		file.Write(sinebuffer);

 		file2.Write(incbuffer);

 		}

 	// Write fine difference to incbuffer - differnece between first and last

 	incbuffer.Zero();

 	incbuffer.AppendFormat(KFormat,first-last);

 	incbuffer.Append(KNewLine);

 	file2.Write(incbuffer);

 	CleanupStack::PopAndDestroy(2);

 	}

 #endif

 //-------------------------------