/*

Copyright (C) 2016 Apple Inc. All Rights Reserved.

See LICENSE.txt for this sample’s licensing information

Abstract:

Part of Core Audio AUBase Classes

*/

#ifndef __AUBuffer_h__

#define __AUBuffer_h__

#include <TargetConditionals.h>

#if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)

    #include <AudioUnit/AudioUnit.h>

#else

    #include <AudioUnit.h>

#endif

#include <string.h>

#include "CAStreamBasicDescription.h"

#include "CAAutoDisposer.h"

#include "CADebugMacros.h"

// make this usable outside the stricter context of AudiUnits

#ifndef COMPONENT_THROW

    #define COMPONENT_THROW(err) \

        do { DebugMessage(#err); throw static_cast<OSStatus>(err); } while (0)

#endif

    /*! @class AUBufferList */

class AUBufferList {

    enum EPtrState {

        kPtrsInvalid,

        kPtrsToMyMemory,

        kPtrsToExternalMemory

    };

public:

    /*! @ctor AUBufferList */

    AUBufferList() : mPtrState(kPtrsInvalid), mExternalMemory(false), mPtrs(NULL), mMemory(NULL), 

        mAllocatedStreams(0), mAllocatedFrames(0), mAllocatedBytes(0) { }

    /*! @dtor ~AUBufferList */

    ~AUBufferList();

    /*! @method PrepareBuffer */

    AudioBufferList &   PrepareBuffer(const CAStreamBasicDescription &format, UInt32 nFrames);

    /*! @method PrepareNullBuffer */

    AudioBufferList &   PrepareNullBuffer(const CAStreamBasicDescription &format, UInt32 nFrames);

    /*! @method SetBufferList */

    AudioBufferList &   SetBufferList(const AudioBufferList &abl) {

                            if (mAllocatedStreams < abl.mNumberBuffers)

                                COMPONENT_THROW(-1);

                            mPtrState = kPtrsToExternalMemory;

                            memcpy(mPtrs, &abl, (char *)&abl.mBuffers[abl.mNumberBuffers] - (char *)&abl);

                            return *mPtrs;

                        }

    /*! @method SetBuffer */

    void                SetBuffer(UInt32 index, const AudioBuffer &ab) {

                            if (mPtrState == kPtrsInvalid || index >= mPtrs->mNumberBuffers)

                                COMPONENT_THROW(-1);

                            mPtrState = kPtrsToExternalMemory;

                            mPtrs->mBuffers[index] = ab;

                        }

    /*! @method InvalidateBufferList */

    void                InvalidateBufferList() { mPtrState = kPtrsInvalid; }

    /*! @method GetBufferList */

    AudioBufferList &   GetBufferList() const {

                            if (mPtrState == kPtrsInvalid)

                                COMPONENT_THROW(-1);

                            return *mPtrs;

                        }

    /*! @method CopyBufferListTo */

    void                CopyBufferListTo(AudioBufferList &abl) const {

                            if (mPtrState == kPtrsInvalid)

                                COMPONENT_THROW(-1);

                            memcpy(&abl, mPtrs, (char *)&abl.mBuffers[abl.mNumberBuffers] - (char *)&abl);

                        }

    /*! @method CopyBufferContentsTo */

    void                CopyBufferContentsTo(AudioBufferList &abl) const {

                            if (mPtrState == kPtrsInvalid)

                                COMPONENT_THROW(-1);

                            const AudioBuffer *srcbuf = mPtrs->mBuffers;

                            AudioBuffer *destbuf = abl.mBuffers;

                            for (UInt32 i = 0; i < abl.mNumberBuffers; ++i, ++srcbuf, ++destbuf) {

                                if (i >= mPtrs->mNumberBuffers) // duplicate last source to additional outputs [4341137]

                                    --srcbuf;

                                if (destbuf->mData != srcbuf->mData)

                                    memmove(destbuf->mData, srcbuf->mData, srcbuf->mDataByteSize);

                                destbuf->mDataByteSize = srcbuf->mDataByteSize;

                            }

                        }

    /*! @method Allocate */

    void                Allocate(const CAStreamBasicDescription &format, UInt32 nFrames);

    /*! @method Deallocate */

    void                Deallocate();

    /*! @method UseExternalBuffer */

    void                UseExternalBuffer(const CAStreamBasicDescription &format, const AudioUnitExternalBuffer &buf);

    // AudioBufferList utilities

    /*! @method ZeroBuffer */

    static void         ZeroBuffer(AudioBufferList &abl) {

                            AudioBuffer *buf = abl.mBuffers;

                            for (UInt32 i = abl.mNumberBuffers ; i--; ++buf)

                                memset(buf->mData, 0, buf->mDataByteSize);

                        }

#if DEBUG

    /*! @method PrintBuffer */

    static void         PrintBuffer(const char *label, int subscript, const AudioBufferList &abl, UInt32 nFrames = 8, bool asFloats = true);

#endif

    /*! @method GetAllocatedFrames */

    UInt32              GetAllocatedFrames() const { return mAllocatedFrames; }

private:

    /*! @ctor AUBufferList */

    AUBufferList(AUBufferList &) { }    // prohibit copy constructor

    /*! @var mPtrState */

    EPtrState                   mPtrState;

    /*! @var mExternalMemory */

    bool                        mExternalMemory;

    /*! @var mPtrs */

    AudioBufferList *           mPtrs;

    /*! @var mMemory */

    Byte *                      mMemory;

    /*! @var mAllocatedStreams */

    UInt32                      mAllocatedStreams;

    /*! @var mAllocatedFrames */

    UInt32                      mAllocatedFrames;

    /*! @var mAllocatedBytes */

    UInt32                      mAllocatedBytes;

};

// Allocates an array of samples (type T), to be optimally aligned for the processor

    /*! @class TAUBuffer */

template <class T>

class TAUBuffer {

public:

    enum { 

        kAlignInterval = 0x10,

        kAlignMask = kAlignInterval - 1

    };

    /*! @ctor TAUBuffer.0 */

    TAUBuffer() :   mMemObject(NULL), mAlignedBuffer(NULL), mBufferSizeBytes(0)

    {

    }

    /*! @ctor TAUBuffer.1 */

    TAUBuffer(UInt32 numElems, UInt32 numChannels) :    mMemObject(NULL), mAlignedBuffer(NULL),

                                                        mBufferSizeBytes(0)

    {

        Allocate(numElems, numChannels);

    }

    /*! @dtor ~TAUBuffer */

    ~TAUBuffer()

    {

        Deallocate();

    }

    /*! @method Allocate */

    void    Allocate(UInt32 numElems)           // can also re-allocate

    {

        UInt32 reqSize = numElems * sizeof(T);

        if (mMemObject != NULL && reqSize == mBufferSizeBytes)

            return; // already allocated

        mBufferSizeBytes = reqSize;

        mMemObject = CA_realloc(mMemObject, reqSize);

        UInt32 misalign = (uintptr_t)mMemObject & kAlignMask;

        if (misalign) {

            mMemObject = CA_realloc(mMemObject, reqSize + kAlignMask);

            mAlignedBuffer = (T *)((char *)mMemObject + kAlignInterval - misalign);

        } else

            mAlignedBuffer = (T *)mMemObject;

    }

    /*! @method Deallocate */

    void    Deallocate()

    {

        if (mMemObject == NULL) return;         // so this method has no effect if we're using

                                                // an external buffer

        free(mMemObject);

        mMemObject = NULL;

        mAlignedBuffer = NULL;

        mBufferSizeBytes = 0;

    }

    /*! @method AllocateClear */

    void    AllocateClear(UInt32 numElems)      // can also re-allocate

    {

        Allocate(numElems);

        Clear();

    }

    /*! @method Clear */

    void    Clear()

    {

        memset(mAlignedBuffer, 0, mBufferSizeBytes);

    }

    // accessors

    /*! @method operator T *()@ */

    operator T *()              { return mAlignedBuffer; }

private:

    /*! @var mMemObject */

    void *      mMemObject;         // null when using an external buffer

    /*! @var mAlignedBuffer */

    T *         mAlignedBuffer;     // always valid once allocated

    /*! @var mBufferSizeBytes */

    UInt32      mBufferSizeBytes;

};

#endif // __AUBuffer_h__