inline all the things

gistfile1.txt

    func createGrainNode() -> AVAudioSourceNode? {
        guard let audioBuffer = self.source?.audioBuffer,
              let sourceData = audioBuffer.floatChannelData else {
            return nil
        }
        
        grainEngine = GrainEngine(withBuffer: sourceData, length: audioBuffer.frameLength, channels: audioBuffer.stride)
        
        let count = 40000
        var grainCount = 0
        
        let bufferLength = audioBuffer.frameLength
        let bufferIndex = bufferLength / 2
        
        let indicesPointer = UnsafeMutablePointer<UInt32>.allocate(capacity: count)

        
        return AVAudioSourceNode { _, _, frameCount, audioBufferList -> OSStatus in
            
            let bufferListPointer = UnsafeMutableAudioBufferListPointer(audioBufferList)
            let density = self.grainEngine?.density ?? 0.0

            for frame in 0..<Int(frameCount) {
                
                if Double(grainCount) < density * Double(count) {
                    grainCount += 1
                }

                var sampleSum = SIMD2<Float>(0.0, 0.0)

                // iterate over grains and accumulate samples
                for i in 0..<grainCount {
                    
                    let index = (indicesPointer+i).pointee
                    let grainIndex:Int = Int((bufferIndex + index) % bufferLength)

                    var sample = SIMD2<Float>(0.0, 0.0)
                    
                    sample.x = sourceData[0][grainIndex]
                    sample.y = sourceData[1][grainIndex]
                    
                    sampleSum += sample
                                        
                    (indicesPointer + i).pointee = (index + 1) % 44100
                }
                                
                sampleSum = sampleSum / Float(grainCount)
                
                for channel in 0..<bufferListPointer.count {
                    let outBuffer:UnsafeMutableBufferPointer<Float> = UnsafeMutableBufferPointer(bufferListPointer[channel])
                    outBuffer[frame] = channel == 0 ? sampleSum.x : sampleSum.y
                }
            }
            return noErr
        }
    }