/*

     File: CAAudioUnitOutputCapturer.h

 Abstract: 

  Version: 1.1.2

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 */

#ifndef __CAAudioUnitOutputCapturer_h__

#define __CAAudioUnitOutputCapturer_h__

#include <AudioToolbox/ExtendedAudioFile.h>

/*

    Class to capture output from an AudioUnit for analysis.

    example:

    CFURL fileurl = CFURLCreateWithFileSystemPath(NULL, CFSTR("/tmp/recording.caf"), kCFURLPOSIXPathStyle, false);

    CAAudioUnitOutputCapturer captor(someAU, fileurl, 'caff', anASBD);

    {

    captor.Start();

    ...

    captor.Stop();

    } // can repeat

    captor.Close(); // can be omitted; happens automatically from destructor

*/

class CAAudioUnitOutputCapturer {

public:

    enum { noErr = 0 };

    CAAudioUnitOutputCapturer(AudioUnit au, CFURLRef outputFileURL, AudioFileTypeID fileType, const AudioStreamBasicDescription &format, UInt32 busNumber = 0) :

        mFileOpen(false),

        mClientFormatSet(false),

        mAudioUnit(au),

        mExtAudioFile(NULL),

        mBusNumber (busNumber)

    {   

        CFShow(outputFileURL);

        OSStatus err = ExtAudioFileCreateWithURL(outputFileURL, fileType, &format, NULL, kAudioFileFlags_EraseFile, &mExtAudioFile);

        if (!err)

            mFileOpen = true;

    }

    void    Start() {

        if (mFileOpen) {

            if (!mClientFormatSet) {

                AudioStreamBasicDescription clientFormat;

                UInt32 size = sizeof(clientFormat);

                AudioUnitGetProperty(mAudioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, mBusNumber, &clientFormat, &size);

                ExtAudioFileSetProperty(mExtAudioFile, kExtAudioFileProperty_ClientDataFormat, size, &clientFormat);

                mClientFormatSet = true;

            }

            ExtAudioFileWriteAsync(mExtAudioFile, 0, NULL); // initialize async writes

            AudioUnitAddRenderNotify(mAudioUnit, RenderCallback, this);

        }

    }

    void    Stop() {

        if (mFileOpen)

            AudioUnitRemoveRenderNotify(mAudioUnit, RenderCallback, this);

    }

    void    Close() {

        if (mExtAudioFile) {

            ExtAudioFileDispose(mExtAudioFile);

            mExtAudioFile = NULL;

        }

    }

    ~CAAudioUnitOutputCapturer() {

        Close();

    }

private:

    static OSStatus RenderCallback( void *                          inRefCon,

                                    AudioUnitRenderActionFlags *    ioActionFlags,

                                    const AudioTimeStamp *          inTimeStamp,

                                    UInt32                          inBusNumber,

                                    UInt32                          inNumberFrames,

                                    AudioBufferList *               ioData)

    {

        if (*ioActionFlags & kAudioUnitRenderAction_PostRender) {

            CAAudioUnitOutputCapturer *This = (CAAudioUnitOutputCapturer *)inRefCon;

            static int TEMP_kAudioUnitRenderAction_PostRenderError  = (1 << 8);

            if (This->mBusNumber == inBusNumber && !(*ioActionFlags & TEMP_kAudioUnitRenderAction_PostRenderError)) {

                ExtAudioFileWriteAsync(This->mExtAudioFile, inNumberFrames, ioData);

            }

        }

        return noErr;

    }

    bool                mFileOpen;

    bool                mClientFormatSet;

    AudioUnit           mAudioUnit;

    ExtAudioFileRef     mExtAudioFile;

    UInt32              mBusNumber;

};

#endif // __CAAudioUnitOutputCapturer_h__