/*

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

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 This class handles buffering of audio data that is shared between the view and audio controller

 */

#include "BufferManager.h"

#define min(x,y) (x < y) ? x : y

BufferManager::BufferManager( UInt32 inMaxFramesPerSlice ) :

mDisplayMode(0 /*aurioTouchDisplayModeOscilloscopeWaveform*/),

mDrawBuffers(),

mDrawBufferIndex(0),

mCurrentDrawBufferLen(kDefaultDrawSamples),

mFFTInputBuffer(NULL),

mFFTInputBufferFrameIndex(0),

mFFTInputBufferLen(inMaxFramesPerSlice),

mHasNewFFTData(0),

mNeedsNewFFTData(0),

mFFTHelper(NULL)

{

    for(UInt32 i=0; i<kNumDrawBuffers; ++i) {

        mDrawBuffers[i] = (Float32*) calloc(inMaxFramesPerSlice, sizeof(Float32));

    }

    mFFTInputBuffer = (Float32*) calloc(inMaxFramesPerSlice, sizeof(Float32));

    mFFTHelper = new FFTHelper(inMaxFramesPerSlice);

    OSAtomicIncrement32Barrier(&mNeedsNewFFTData);

}

BufferManager::~BufferManager()

{

    for(UInt32 i=0; i<kNumDrawBuffers; ++i) {

        free(mDrawBuffers[i]);

        mDrawBuffers[i] = NULL;

    }

    free(mFFTInputBuffer);

    delete mFFTHelper; mFFTHelper = NULL;

}

void BufferManager::CopyAudioDataToDrawBuffer( Float32* inData, UInt32 inNumFrames )

{

    if (inData == NULL) return;

    for (UInt32 i=0; i<inNumFrames; i++)

    {

        if ((i+mDrawBufferIndex) >= mCurrentDrawBufferLen)

        {

            CycleDrawBuffers();

            mDrawBufferIndex = -i;

        }

        mDrawBuffers[0][i + mDrawBufferIndex] = inData[i];

    }

    mDrawBufferIndex += inNumFrames;

}

void BufferManager::CycleDrawBuffers()

{

    // Cycle the lines in our draw buffer so that they age and fade. The oldest line is discarded.

    for (int drawBuffer_i=(kNumDrawBuffers - 2); drawBuffer_i>=0; drawBuffer_i--)

        memmove(mDrawBuffers[drawBuffer_i + 1], mDrawBuffers[drawBuffer_i], mCurrentDrawBufferLen);

}

void BufferManager::CopyAudioDataToFFTInputBuffer( Float32* inData, UInt32 numFrames )

{

    UInt32 framesToCopy = min(numFrames, mFFTInputBufferLen - mFFTInputBufferFrameIndex);

    memcpy(mFFTInputBuffer + mFFTInputBufferFrameIndex, inData, framesToCopy * sizeof(Float32));

    mFFTInputBufferFrameIndex += framesToCopy * sizeof(Float32);

    if (mFFTInputBufferFrameIndex >= mFFTInputBufferLen) {

        OSAtomicIncrement32(&mHasNewFFTData);

        OSAtomicDecrement32(&mNeedsNewFFTData);

    }

}

void BufferManager::GetFFTOutput( Float32* outFFTData )

{

    mFFTHelper->ComputeFFT(mFFTInputBuffer, outFFTData);

    mFFTInputBufferFrameIndex = 0;

    OSAtomicDecrement32Barrier(&mHasNewFFTData);

    OSAtomicIncrement32Barrier(&mNeedsNewFFTData);

}