/*

     File: AUOutputBL.h 

 Abstract:  Part of CoreAudio Utility Classes  

  Version: 1.0 

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*/

#ifndef __AUOutputBL_h__

#define __AUOutputBL_h__

#include "CAStreamBasicDescription.h"

#if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)

#else

#endif

// ____________________________________________________________________________

//

//  AUOutputBL - Simple Buffer List wrapper targetted to use with retrieving AU output

// Works in one of two ways (both adjustable)... Can use it with NULL pointers, or allocate

// memory to receive the data in.

// Before using this with any call to AudioUnitRender, it needs to be Prepared

// as some calls to AudioUnitRender can reset the ABL

class AUOutputBL {

public:

                                            // you CANNOT use one of these - it will crash!

//                                      AUOutputBL ();

                                            // this is the constructor that you use

                                            // it can't be reset once you've constructed it

                                        AUOutputBL (const CAStreamBasicDescription &inDesc, UInt32 inDefaultNumFrames = 512);

                                        ~AUOutputBL();

    void                                Prepare ()

                                        {

                                            Prepare (mFrames);

                                        }

                                // this version can throw if this is an allocted ABL and inNumFrames is > AllocatedFrames()

                                // you can set the bool to true if you want a NULL buffer list even if allocated

                                // inNumFrames must be a valid number (will throw if inNumFrames is 0)

    void                                Prepare (UInt32 inNumFrames, bool inWantNullBufferIfAllocated = false);

    AudioBufferList*                    ABL() { return mBufferList; }

                                // You only need to call this if you want to allocate a buffer list

                                // if you want an empty buffer list, just call Prepare()

                                // if you want to dispose previously allocted memory, pass in 0

                                // then you either have an empty buffer list, or you can re-allocate

                                // Memory is kept around if an Allocation request is less than what is currently allocated

    void                                Allocate (UInt32 inNumberFrames);

    UInt32                              AllocatedFrames() const { return mFrames; }

    const CAStreamBasicDescription&     GetFormat() const { return mFormat; }

#if DEBUG

    void                                Print();

#endif

private:

    UInt32                      AllocatedBytes () const { return (mBufferSize * mNumberBuffers); }

    CAStreamBasicDescription    mFormat;

    Byte*                       mBufferMemory;

    AudioBufferList*            mBufferList;

    UInt32                      mNumberBuffers;

    UInt32                      mBufferSize;

    UInt32                      mFrames;

// don't want to copy these.. can if you want, but more code to write!

    AUOutputBL () {}

    AUOutputBL (const AUOutputBL &c);

    AUOutputBL& operator= (const AUOutputBL& c);

};

#endif // __AUOutputBL_h__