/*

* Copyright (c) 2002-2004 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: Audio Stubs -  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 FILES

#include <e32math.h>

#include <mda/common/resource.h>

// CONSTANTS

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

*	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;

const TInt KRecalculateToneLengths = KMinTInt;

//

// Sequence constants

//

#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;

//

// 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

	};

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 #

	};

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

// LOCAL_C void RampVolume

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

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

// (other items were commented in a header).

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

//

LOCAL_C void RampVolume(

	TInt16* aData,

	TInt aCount,

	TInt aStartVol,

	TInt aEndVol)

	{

	TInt step = (aEndVol - aStartVol)/aCount;

	while (aCount--)

		{

		TInt data = TInt(*aData) * aStartVol;

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

		aStartVol += step;

		}

	}

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

// GenerateSineTableL

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

// Optionally called from InitL()

// (other items were commented in a header).

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

// #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(file2);

	CleanupStack::PopAndDestroy(file);

	}

#endif

// ============================ MEMBER FUNCTIONS ===============================

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

// TSineGen::SetFrequency

// 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.

// (other items were commented in a header).

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

//

void TSineGen::SetFrequency(

	TInt aFrequency,

	TInt aAmplitude)

	{

	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);

	}

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

// TSineGen::NextSample

// Generate the next sample using linear interpolation

// (other items were commented in a header).

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

//

TInt TSineGen::NextSample()

	{

	TUint pos=iPosition>>24;

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

	amp>>=4;

	amp+=SineTable[pos];

	amp=(amp*iAmplitude)>>15;

	iPosition+=iStep;

	return(amp);

	}

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

// TSineWave::Generate

// Called when more samples need to be generated.

// (other items were commented in a header).

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

//

void TSineWave::Generate(

	TInt16* aDest,

	TInt aCount)

	{

	while (aCount--)

		{

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

		}

	}

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

// TSineWave::SetFrequency

// Set to generate a single frequency

// (other items were commented in a header).

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

//

void TSineWave::SetFrequency(

	TInt aFrequency,

	TInt aAmplitude)

	{

	SetFrequency(aFrequency,aAmplitude,0,0);

	}

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

// TSineWave::SetFrequency

// Set to generate two frequencies

// (other items were commented in a header).

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

//

void TSineWave::SetFrequency(

	TInt aFrequency1,

	TInt aAmplitude1,

	TInt aFrequency2,

	TInt aAmplitude2)

	{

	iGen1.SetFrequency(aFrequency1,aAmplitude1);

	iGen2.SetFrequency(aFrequency2,aAmplitude2);

	}

//

// TMdaToneGenerator

//

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

// TMdaToneGenerator::Configure

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

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

// (other items were commented in a header).

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

//

void TMdaToneGenerator::Configure(

	TInt aRate,

	TInt aChannels,

	TInt aRepeats,

	TInt aSilence,

	TInt aRampUp)

	{

	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;

	}

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

// TMdaToneGenerator::FillBuffer

// 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

// (other items were commented in a header).

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

//

TInt TMdaToneGenerator::FillBuffer(

	TDes8& aBuffer)

	{

	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;

		}