/*

    File: ACAppleIMA4Decoder.cpp

Abstract: ACAppleIMA4Decoder.cpp file for AudioCodecSDK.

 Version: 1.0

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*/

//=============================================================================

//  Includes

//=============================================================================

#include "ACAppleIMA4Decoder.h"

#include "CAStreamBasicDescription.h"

#include "CADebugMacros.h"

#include "CABundleLocker.h"

//=============================================================================

//  ACAppleIMA4Decoder

//=============================================================================

ACAppleIMA4Decoder::ACAppleIMA4Decoder(AudioComponentInstance inInstance)

:

    ACAppleIMA4Codec(kInputBufferPackets * kIMA4PacketBytes, inInstance)

{    

    //  This decoder only takes an Apple IMA4 stream as it's input

    CAStreamBasicDescription theInputFormat(kAudioStreamAnyRate, 'DEMO', 0, kIMAFramesPerPacket, 0, 0, 0, 0);

    AddInputFormat(theInputFormat);

    //  set our initial input format to mono Apple IMA4 at a 44100 sample rate

    mInputFormat.mFormatID = 'DEMO';

    mInputFormat.mBytesPerPacket = kIMA4PacketBytes;

    mInputFormat.mFramesPerPacket = kIMAFramesPerPacket;

    mInputFormat.mSampleRate = 44100;

    mInputFormat.mFormatFlags = 0;

    mInputFormat.mBytesPerFrame = 0;

    mInputFormat.mChannelsPerFrame = 1;

    mInputFormat.mBitsPerChannel = 0;

    //  This decoder produces 16 bit native endian signed integer

    //  It can handle any sample rate and any number of channels

    CAStreamBasicDescription theOutputFormat1(kAudioStreamAnyRate, kAudioFormatLinearPCM, 0, 1, 0, 0, 16, kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked);

    AddOutputFormat(theOutputFormat1);

    //  set our intial output format to mono 16 bit native endian integers at a 44100 sample rate

    mOutputFormat.mSampleRate = 44100;

    mOutputFormat.mFormatID = kAudioFormatLinearPCM;

    mOutputFormat.mFormatFlags = kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;

    mOutputFormat.mBytesPerPacket = 2;

    mOutputFormat.mFramesPerPacket = 1;

    mOutputFormat.mBytesPerFrame = 2;

    mOutputFormat.mChannelsPerFrame = 1;

    mOutputFormat.mBitsPerChannel = 16;

    //  initialize our channel state

    InitializeChannelStateList();

}

ACAppleIMA4Decoder::~ACAppleIMA4Decoder()

{

}

void    ACAppleIMA4Decoder::GetProperty(AudioCodecPropertyID inPropertyID, UInt32& ioPropertyDataSize, void* outPropertyData)

{   

    switch(inPropertyID)

    {

#if !BUILD_ADEC_LIB

        case kAudioCodecPropertyNameCFString:

        {

            if (ioPropertyDataSize != SizeOf32(CFStringRef)) CODEC_THROW(kAudioCodecBadPropertySizeError);

            CABundleLocker lock;

            CFStringRef name = CFCopyLocalizedStringFromTableInBundle(CFSTR("Acme IMA4 decoder"), CFSTR("CodecNames"), GetCodecBundle(), CFSTR(""));

            *(CFStringRef*)outPropertyData = name;

            break; 

        }

#endif

       case kAudioCodecPropertyMaximumPacketByteSize:

            if(ioPropertyDataSize == SizeOf32(UInt32))

            {

                *reinterpret_cast<UInt32*>(outPropertyData) = kIMA4PacketBytes * mInputFormat.mChannelsPerFrame;

            }

            else

            {

                CODEC_THROW(kAudioCodecBadPropertySizeError);

            }

            break;

        case kAudioCodecPropertyPacketFrameSize:

            if(ioPropertyDataSize == SizeOf32(UInt32))

            {

                *reinterpret_cast<UInt32*>(outPropertyData) = kIMAFramesPerPacket;

            }

            else

            {

                CODEC_THROW(kAudioCodecBadPropertySizeError);

            }

            break;

        default:

            ACAppleIMA4Codec::GetProperty(inPropertyID, ioPropertyDataSize, outPropertyData);

    }

}

void    ACAppleIMA4Decoder::SetCurrentInputFormat(const AudioStreamBasicDescription& inInputFormat)

{

    if(!mIsInitialized)

    {

        AudioStreamBasicDescription tempInputFormat = inInputFormat;

        //  check to make sure the input format is legal

        if(tempInputFormat.mFormatID != mCodecSubType)

        {

#if VERBOSE

            DebugMessage("ACAppleIMA4Decoder::SetCurrentInputFormat: only support Acme IMA for output");

#endif

            CODEC_THROW(kAudioCodecUnsupportedFormatError);

        }

        if (tempInputFormat.mFramesPerPacket != kIMAFramesPerPacket)

        {

#if VERBOSE

            DebugMessage("ACAppleIMA4Decoder::SetCurrentInputFormat: only supports 64 frames per packet");

#endif

            CODEC_THROW(kAudioCodecUnsupportedFormatError);

        }

        // Do same basic sanity checks

        if(tempInputFormat.mSampleRate < 0.0)

        {

    #if VERBOSE

            DebugMessage("ACAppleIMA4Decoder::SetCurrentInputFormat: input sample rates may not be negative");

    #endif

            CODEC_THROW(kAudioCodecUnsupportedFormatError);

        }

        if (kMaxIMA4Channels < tempInputFormat.mChannelsPerFrame)

        {

    #if VERBOSE

            DebugMessage("ACAppleIMA4Decoder::SetCurrentInputFormat: only supports up to 2 channels for input");

    #endif

            CODEC_THROW(kAudioCodecUnsupportedFormatError);

        }

        if (tempInputFormat.mBytesPerPacket > tempInputFormat.mChannelsPerFrame * SizeOf32(SInt16) * tempInputFormat.mFramesPerPacket)

        {

    #if VERBOSE

            DebugMessage("ACAppleIMA4Decoder::SetCurrentInputFormat: bytes per packet is too large");

    #endif

            CODEC_THROW(kAudioCodecUnsupportedFormatError);

        }

        //  tell our base class about the new format

        ACAppleIMA4Codec::SetCurrentInputFormat(tempInputFormat);

        // The decoder does no sample rate conversion nor channel manipulation

        if (tempInputFormat.mChannelsPerFrame == 0)

        {

            mInputFormat.mChannelsPerFrame = mOutputFormat.mChannelsPerFrame;

        }

        else

        {

            mOutputFormat.mChannelsPerFrame = mInputFormat.mChannelsPerFrame;

        }

        if (tempInputFormat.mSampleRate == 0.0)

        {

            mInputFormat.mSampleRate = mOutputFormat.mSampleRate;

        }

        else

        {

            mOutputFormat.mSampleRate = mInputFormat.mSampleRate;

        }

        // Zero out everything that has to be zero

        mInputFormat.mBytesPerFrame = 0;

        mInputFormat.mBitsPerChannel = 0;

        mInputFormat.mFormatFlags = 0;

        mInputFormat.mReserved = 0;

        // This needs to be calculated out

        mInputFormat.mBytesPerPacket = kIMA4PacketBytes * mInputFormat.mChannelsPerFrame;

    }

    else

    {

        CODEC_THROW(kAudioCodecStateError);

    }

}

void    ACAppleIMA4Decoder::SetCurrentOutputFormat(const AudioStreamBasicDescription& inOutputFormat)

{

    if(!mIsInitialized)

    {

        //  check to make sure the output format is legal

        if( (inOutputFormat.mFormatID != kAudioFormatLinearPCM) ||

            !( (inOutputFormat.mFormatFlags == (kLinearPCMFormatFlagIsSignedInteger | kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked) ) &&

               (inOutputFormat.mBitsPerChannel == 16) ) )

        {

#if VERBOSE

            DebugMessage("ACAppleIMA4Decoder::SetCurrentOutputFormat: only supports 16 bit native endian signed integers for output");

#endif

            CODEC_THROW(kAudioCodecUnsupportedFormatError);

        }

        // Do some basic sanity checks

        if(inOutputFormat.mSampleRate < 0.0)

        {

    #if VERBOSE

            DebugMessage("ACAppleIMA4Decoder::SetCurrentOutputFormat: output sample rates may not be negative");

    #endif

            CODEC_THROW(kAudioCodecUnsupportedFormatError);

        }       

        if (kMaxIMA4Channels < inOutputFormat.mChannelsPerFrame)

        {

    #if VERBOSE

            DebugMessage("ACAppleIMA4Decoder::SetCurrentOutputFormat: only supports up to 2 channels for output");

    #endif

            CODEC_THROW(kAudioCodecUnsupportedFormatError);

        }

        //  tell our base class about the new format

        ACAppleIMA4Codec::SetCurrentOutputFormat(inOutputFormat);

        if (mOutputFormat.mSampleRate == 0.0)

        {

            mOutputFormat.mSampleRate = mInputFormat.mSampleRate;

        }

        if (mOutputFormat.mChannelsPerFrame == 0)

        {

            mOutputFormat.mChannelsPerFrame = mInputFormat.mChannelsPerFrame;

        }

        // Fix values that are derived from the others

        mOutputFormat.mBytesPerPacket = mOutputFormat.mBytesPerFrame = mOutputFormat.mChannelsPerFrame * (mOutputFormat.mBitsPerChannel >> 3);

        mOutputFormat.mFramesPerPacket = 1; // always       

        // Zero out everything that has to be zero

        mOutputFormat.mReserved = 0;

    }

    else

    {

        CODEC_THROW(kAudioCodecStateError);

    }

}

UInt32  ACAppleIMA4Decoder::ProduceOutputPackets(void* outOutputData, UInt32& ioOutputDataByteSize, UInt32& ioNumberPackets, AudioStreamPacketDescription* outPacketDescription)

{

    //  setup the return value, by assuming that everything is going to work

    UInt32 theAnswer = kAudioCodecProduceOutputPacketSuccess;

    if(!mIsInitialized)

    {

        CODEC_THROW(kAudioCodecStateError);

    }

    //  Note that the decoder doesn't suffer from the same problem the encoder

    //  does with not having enough data for a packet, since the encoded data

    //  is always going to be in whole packets.

    //  clamp the number of packets to produce based on what is available in the input buffer

    UInt32 inputPacketSize = mInputFormat.mBytesPerPacket;

    UInt32 numberOfInputPackets = GetUsedInputBufferByteSize() / inputPacketSize;

    if (ioNumberPackets < numberOfInputPackets)

    {

        numberOfInputPackets = ioNumberPackets;

    }

    else if (ioNumberPackets > numberOfInputPackets)

    {

        ioNumberPackets = numberOfInputPackets;

        //  this also means we need more input to satisfy the request so set the return value

        theAnswer = kAudioCodecProduceOutputPacketNeedsMoreInputData;

    }

    // We only produce 1 at a time

    if (ioNumberPackets > 1 && numberOfInputPackets > 1)

    {

        numberOfInputPackets = ioNumberPackets = 1;

        theAnswer = kAudioCodecProduceOutputPacketSuccessHasMore;

    }

    UInt32 inputByteSize = numberOfInputPackets * inputPacketSize;

    if(ioNumberPackets > 0)

    {

        //  make sure that there is enough space in the output buffer for the encoded data

        //  it is an error to ask for more output than you pass in buffer space for

        UInt32 theOutputByteSize = ioNumberPackets * mInputFormat.mFramesPerPacket * mOutputFormat.mBytesPerFrame;

        ThrowIf(ioOutputDataByteSize < theOutputByteSize, static_cast<OSStatus>(kAudioCodecNotEnoughBufferSpaceError), "ACAppleIMA4Decoder::ProduceOutputPackets: not enough space in the output buffer");

        //  set the return value

        ioOutputDataByteSize = theOutputByteSize;

        //  decode the input data for each channel

        Byte* theInputData = GetBytes(inputByteSize);

        SInt16* theOutputData = reinterpret_cast<SInt16*>(outOutputData);

        ChannelStateList::iterator theIterator = mChannelStateList.begin();

        for(UInt32 theChannelIndex = 0; theChannelIndex < mOutputFormat.mChannelsPerFrame; ++theChannelIndex)

        {

            //printf("->DecodeChannel %d %d %d %08X %08X\n", mOutputFormat.mChannelsPerFrame, theChannelIndex, ioNumberPackets, theInputData, theOutputData);

            DecodeChannelSInt16(*theIterator, mOutputFormat.mChannelsPerFrame, theChannelIndex, ioNumberPackets, theInputData, theOutputData);

            std::advance(theIterator, 1);

        }

        ConsumeInputData(inputByteSize);

    }

    else

    {

        //  set the return value since we're not actually doing any work

        ioOutputDataByteSize = 0;

    }

    if((theAnswer == kAudioCodecProduceOutputPacketSuccess) && (GetUsedInputBufferByteSize() >= inputPacketSize))

    {

        //  we satisfied the request, and there's at least one more full packet of data we can decode

        //  so set the return value

        theAnswer = kAudioCodecProduceOutputPacketSuccessHasMore;

    }

    return theAnswer;

}

void    ACAppleIMA4Decoder::DecodeChannelSInt16(ChannelState& ioChannelState, UInt32 inNumberChannels, UInt32 inDecodeChannel, UInt32 inNumberPacketsToDecode, const Byte* inInputData, SInt16* outOutputData)

{

    //  This decoder can only decode one channel at a time.

    //  Each channel in a packet of frames is encoded separately and

    //  the resulting channel packets are interleaved in channel order.

    //  We need to figure out how to skip through the input and output buffers

    //  and point at the appropriate place in the data to start off

    UInt32  theInputStride  = (inNumberChannels - 1) * kIMA4PacketBytes + 2;

    Byte*   theInputData    = const_cast<Byte*>(inInputData) + (inDecodeChannel * kIMA4PacketBytes);

    UInt32  theOutputStride = inNumberChannels;

    SInt32 theDifference;

    SInt32 theCode = 0;

    UInt32 theTemporaryInputData = 0;                   /* initialize so warnings go away */

    SInt16* theOutputData   = const_cast<SInt16*>(outOutputData) + inDecodeChannel;

    if (inNumberPacketsToDecode == 0)

        return;

    CheckState(theInputData, ioChannelState);                       /* make sure state predictors match stream */

    theInputData += 2;                                      /* skip first predictor */

    SInt32 thePredictedSample = ioChannelState.mPredictedSample;                    /* continue where we left off last time */

    SInt32  theStepTableIndex = ioChannelState.mStepTableIndex;

    SInt32  theStep = sStepTable[theStepTableIndex];

    for (; inNumberPacketsToDecode > 0; --inNumberPacketsToDecode)

    {

        //printf("inNumberPacketsToDecode %d\n", inNumberPacketsToDecode);

        for(UInt32 theNumberSamplesLeft = kIMAFramesPerPacket; theNumberSamplesLeft > 0; --theNumberSamplesLeft)

        {

            if  (theNumberSamplesLeft & 1)                      /* two samples per input char */

                theCode = theTemporaryInputData >> 4;

            else

            {

                //printf("IN %02X\n", *theInputData & 255);

                theTemporaryInputData = *theInputData++;                    /* buffer two ADPCM nibbles */

                theCode = theTemporaryInputData & 0x0F;

            }

            theDifference = 0;                              /* compute new sample estimate thePredictedSample */

            if (theCode & 4)

                theDifference += theStep;

            if (theCode & 2)

                theDifference += theStep >> 1;

            if (theCode & 1)

                theDifference += theStep >> 2;

            theDifference += theStep >> 3;

            if (theCode & 8)

                theDifference = -theDifference;

            thePredictedSample += theDifference;

            //  check for overflow

            if(thePredictedSample > 32767)

            {

                thePredictedSample = 32767;

            }

            else if(thePredictedSample < -32768)

            {

                thePredictedSample = -32768;

            }

            //printf("   theCode %02X  theDifference %d\n", theCode, theDifference);

            //printf("OUT %02X %d   \n", thePredictedSample & 255, thePredictedSample);

            *theOutputData = thePredictedSample;

            theOutputData += theOutputStride;

            theStepTableIndex += sIndexTable[theCode];              /* compute new stepsize step */

            if (theStepTableIndex < 0)

                theStepTableIndex = 0;

            else if (theStepTableIndex > 88)

                theStepTableIndex = 88;

            theStep = sStepTable[theStepTableIndex];

            //printf("   theStep %d  theStepTableIndex %d\n", theStep, theStepTableIndex);

        }

        theInputData += theInputStride;

    }

    ioChannelState.mPredictedSample = thePredictedSample;

    ioChannelState.mStepTableIndex = theStepTableIndex;

}

UInt32  ACAppleIMA4Decoder::GetVersion() const

{

    return kIMA4adecVersion;

}

#include "ACPlugInDispatch.h"

AUDIOCOMPONENT_ENTRY(AudioCodecFactory, ACAppleIMA4Decoder)

const SInt32 kPredTolerance = 0x007F;

const UInt32 kIndexMask = 0x007F;

const UInt32 kPredictorMask = 0xFF80;

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

void ACAppleIMA4Decoder::CheckState(const Byte *inInputData, ChannelState& ioChannelState)

{

    SInt16 s = CFSwapInt16BigToHost(*((short *) inInputData));

    SInt16 theStepTableIndex = s & kIndexMask;                  // get stored index

    s &= kPredictorMask;                    // get stored thePredictedSample

    SInt32 thePredictedSample = s;                          // make sure it gets sign-extended!

    if (theStepTableIndex == ioChannelState.mStepTableIndex)                // indexes match

    {

        SInt32 theDifference = thePredictedSample - ioChannelState.mPredictedSample;    // calculate theDifference between state and stored value

        if (theDifference < 0)

            theDifference = -theDifference;

        if (theDifference <= kPredTolerance)            // is difference greater than tolerance?

            return;                         // no, so state is good

    }

    ioChannelState.mPredictedSample = thePredictedSample;           // use stored state

    ioChannelState.mStepTableIndex = theStepTableIndex;

}

void ACAppleIMA4Decoder::FixFormats()

{

    mInputFormat.mFramesPerPacket = 64;

    mInputFormat.mBytesPerPacket = mInputFormat.mChannelsPerFrame * 34;

    mInputFormat.mBytesPerFrame = 0;

}