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// Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).
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// All rights reserved.
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// This component and the accompanying materials are made available
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// under the terms of "Eclipse Public License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.eclipse.org/legal/epl-v10.html".
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//
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// Initial Contributors:
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// Nokia Corporation - initial contribution.
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//
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// Contributors:
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//
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// Description:
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//
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#include "MMFAudioALawToS16PcmCodec.h"
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/***
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*
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* Convert
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*
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*/
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EXPORT_C void TMMFAudioALawToS16PcmCodec::Convert(TUint8* aSrc, TUint8* aDst, TInt aSamples)
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{
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ASSERT(aSrc);
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ASSERT(aDst);
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TInt pcm;
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while (aSamples--)
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{
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pcm = AlawSampleToPcm(*aSrc++);
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*aDst++ = STATIC_CAST( TUint8, pcm&KAndMask8bit);
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*aDst++ = STATIC_CAST( TUint8, pcm>>8);
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}
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}
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/***
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*
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* AlawSampleToPcm
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* @param aLaw
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* @return TInt
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*
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*/
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TInt TMMFAudioALawToS16PcmCodec::AlawSampleToPcm(TUint8 aAlaw)
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{
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TInt sign, exponent, mantissa, sample;
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aAlaw ^= 0x55; //will leave this as is, more readable
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sign = ( aAlaw & KMaskSign8bit );
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aAlaw &= 0x7f; /* get magnitude */
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if (aAlaw >= 16)
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{
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exponent = (aAlaw >> 4 ) & 0x07;
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mantissa = aAlaw & 0x0F;
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sample = KExpLut[exponent] + ( mantissa << ( exponent + 3 ) );
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}
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else
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sample = (aAlaw << 4) + 8;
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if ( sign == 0 )
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sample = -sample;
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return sample;
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}
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const TInt TMMFAudioALawToS16PcmCodec::KExpLut[] =
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{
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0, 264, 528, 1056, 2112, 4224, 8448, 16896
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};
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