/*

    File: ACAppleIMA4Codec.h

Abstract: ACAppleIMA4Codec.h file for AudioCodecSDK.

 Version: 1.0

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*/

#if !defined(__ACAppleIMA4Codec_h__)

#define __ACAppleIMA4Codec_h__

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

//  Includes

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

#include <CoreAudio/CoreAudio.h>

#include <AudioToolbox/AudioFormat.h>

#include <AudioUnit/AudioCodec.h>

#include "ACSimpleCodec.h"

#include <vector>

#include "ACVersions_IMA.h"

#define kMaxIMA4Channels 2

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

//  ACAppleIMA4Codec

//

//  This class encapsulates the common implementation of an Apple IMA codec.

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

class ACAppleIMA4Codec

:

    public ACSimpleCodec

{

//  Construction/Destruction

public:

                        ACAppleIMA4Codec(UInt32 inInputBufferByteSize, AudioComponentInstance inInstance);

    virtual             ~ACAppleIMA4Codec();

//  Data Handling

public:

    virtual void        Initialize(const AudioStreamBasicDescription* inInputFormat, const AudioStreamBasicDescription* inOutputFormat, const void* inMagicCookie, UInt32 inMagicCookieByteSize);

    virtual void        Uninitialize();

    virtual void        Reset();

    virtual void        FixFormats()=0;

    virtual void        GetProperty(AudioCodecPropertyID inPropertyID, UInt32& ioPropertyDataSize, void* outPropertyData);

    virtual void        GetPropertyInfo(AudioCodecPropertyID inPropertyID, UInt32& outPropertyDataSize, Boolean& outWritable);

    virtual void        SetProperty(AudioCodecPropertyID inPropertyID, UInt32 inPropertyDataSize, const void* inPropertyData);

//  Implementation

protected:

    void                InitializeChannelStateList();

    void                ResetChannelStateList();

    struct  ChannelState

    {

        SInt32          mPredictedSample;

        SInt16          mStepTableIndex;

        ChannelState() : mPredictedSample(0), mStepTableIndex(0) {}

        void Reset() { mPredictedSample = 0; mStepTableIndex = 0; }

    };

    typedef std::vector<ChannelState>   ChannelStateList;

    ChannelStateList    mChannelStateList;

//  Implementation Constants

protected:

    enum

    {

        kIMAFramesPerPacket = 64,

        kBytesPerChannelPerPacket = 32,

        kHeaderBytes = 2,

        kInputBufferPackets = 32,

        kIMA4PacketBytes = kHeaderBytes + kBytesPerChannelPerPacket

    };

    static const UInt16 kPredictorMask;

    static const UInt16 kStepTableIndexMask;

    static const SInt32 kPredictorTolerance;

    static const SInt16 sIndexTable[16];

    static const SInt16 sStepTable[89];

};

#endif