//
//  dsp.h
//  Kraken Engine / Siren
//
//  Copyright 2023 Kearwood Gilbert. All rights reserved.
//  
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//  permitted provided that the following conditions are met:
//  
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//  2. Redistributions in binary form must reproduce the above copyright notice, this list
//  of conditions and the following disclaimer in the documentation and/or other materials
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//  THIS SOFTWARE IS PROVIDED BY KEARWOOD GILBERT ''AS IS'' AND ANY EXPRESS OR IMPLIED
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//

#pragma once

namespace siren {
namespace dsp {

#ifdef __APPLE__
#define SIREN_DSP_APPLE_VDSP
#include <Accelerate/Accelerate.h>
#else
// Slow, but portable fallback implementation
#define SIREN_DSP_SLOW
#endif

#if defined(SIREN_DSP_APPLE_VDSP)

  // Apple vDSP
typedef DSPSplitComplex SplitComplex;
struct FFTWorkspace
{
  FFTSetup setup;

  void create(size_t length);
  void destroy();
  FFTWorkspace();
  ~FFTWorkspace();
};

#elif defined(SIREN_DSP_SLOW)

typedef struct
{
  float* realp;
  float* imagp;
} SplitComplex;

struct FFTWorkspace
{
  float* sin_table;
  float* cos_table;

  void create(size_t length);
  void destroy();
  FFTWorkspace();
  ~FFTWorkspace();
};

#else
#error Not Implemented
#endif

void FFTForward(const FFTWorkspace& workspace, SplitComplex* src, size_t count);
void FFTInverse(const FFTWorkspace& workspace, SplitComplex* src, size_t count);
void Int16ToFloat(const short* src, size_t srcStride, float* dest, size_t destStride, size_t count);
void Scale(float* buffer, float scale, size_t count);
void ScaleCopy(const float* src, float scale, float* dest, size_t count);
void ScaleCopy(const SplitComplex* src, float scale, SplitComplex* dest, size_t count);
void ScaleRamp(float* buffer, float scaleStart, float scaleStep, size_t count);
void Accumulate(float* buffer, size_t bufferStride, const float* buffer2, size_t buffer2Stride, size_t count);
void Accumulate(SplitComplex* buffer, const SplitComplex* buffer2, size_t count);
void Multiply(const SplitComplex* a, const SplitComplex* b, SplitComplex* c, size_t count);

} // namespace dsp
} // namespace siren