// Copyright (c) 2003-2009 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:

 // MMFAudioImaAdpcmToS16PcmCodec.cpp

 // 

 //

 #include "MMFAudioImaAdpcmToS16PcmCodec.h"

 /**

 *

 * Convert

 * @param aSrc

 * @param aDst

 * @param aSamples

 *

 */

 EXPORT_C void TMMFAudioImaAdpcmToS16PcmCodec::Convert(TUint8* aSrc, TUint8* aDst, TInt aSamples)

 	{

 	TInt delta;			// Current adpcm output value 

     TInt step;			// Stepsize

     TInt valpred;		// Predicted value 

     TInt vpdiff;		// Current change to valpred 

     TInt index;			// Current step change index 

 	//[Read first sample and index from block header

 	// we do not need to store the information across calls 

 	//since we process the entire block here]

 	valpred = (*aSrc++) & KAndMask8bit;

 	valpred |= STATIC_CAST(TInt16, ((*aSrc++) << 8));

 	index = *aSrc++;

 	TUint8* dst=aDst;

 	aSrc++; //skip reserved header byte

 	//Write first sample to dest

 	*aDst++ = STATIC_CAST( TUint8, valpred);

 	*aDst++ = STATIC_CAST( TUint8, valpred >> 8);

 	dst += 2;

 	aSamples --;

 	TBool theBufferStep = ETrue;

     TInt  bufferValue = 0;

 	for ( ; aSamples > 0 ; aSamples-- ) 

 		{ 

 		// Step 1 - get the delta value

 		if ( theBufferStep) 

 			{

 			bufferValue = *aSrc++;

 			delta = bufferValue & 0xf;

 			} 

 		else 

 			{

 			delta = (bufferValue >> 4) & 0xf;

 			}

 		theBufferStep = !theBufferStep;

 		ASSERT(index >= 0);

 		step = KStepSizeTable[index];

 		vpdiff = step>>3;

 		if ( delta & 4 ) 

 			vpdiff += step;

 		if ( delta & 2 ) 

 			vpdiff += step>>1;

 		if ( delta & 1 ) 

 			vpdiff += step>>2;

 		if ( delta & 8 )

 			valpred -= vpdiff;

 		else

 			valpred += vpdiff;

 		if ( valpred > (KClamp - 1) )

 			valpred = (KClamp - 1);

 		else if ( valpred < -KClamp )

 			valpred = -KClamp;

 		index += KIndexTable[delta];

 		if ( index < 0 ) 

 			index = 0;

 		if ( index > KMaxImaAdpcmTableEntries ) 

 			index = KMaxImaAdpcmTableEntries;

 		*dst++ = STATIC_CAST( TUint8, valpred&KAndMask8bit);

 		*dst++ = STATIC_CAST( TUint8, (valpred>>8) );

 		}

 	}

 // IMA-ADPCM step variation table 

 const TInt TMMFAudioImaAdpcmToS16PcmCodec::KIndexTable[] =

  	{

     -1, -1, -1, -1, 2, 4, 6, 8,

     -1, -1, -1, -1, 2, 4, 6, 8

 	};

 const TInt TMMFAudioImaAdpcmToS16PcmCodec::KStepSizeTable[89] = 

 	{

    7, 8, 9, 10, 11, 12, 13, 14, 16, 17,

    19, 21, 23, 25, 28, 31, 34, 37, 41, 45,

    50, 55, 60, 66, 73, 80, 88, 97, 107, 118,

    130, 143, 157, 173, 190, 209, 230, 253, 279, 307,

    337, 371, 408, 449, 494, 544, 598, 658, 724, 796,

    876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,

    2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,

    5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,

    15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767

 	};