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/*
* Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef MODULES_AUDIO_PROCESSING_UTILITY_PFFFT_WRAPPER_H_
#define MODULES_AUDIO_PROCESSING_UTILITY_PFFFT_WRAPPER_H_
#include <memory>
#include "api/array_view.h"
// Forward declaration.
struct PFFFT_Setup;
namespace webrtc {
// Pretty-Fast Fast Fourier Transform (PFFFT) wrapper class.
// Not thread safe.
class Pffft {
public:
enum class FftType { kReal, kComplex };
// 1D floating point buffer used as input/output data type for the FFT ops.
// It must be constructed using Pffft::CreateBuffer().
class FloatBuffer {
public:
FloatBuffer(const FloatBuffer&) = delete;
FloatBuffer& operator=(const FloatBuffer&) = delete;
~FloatBuffer();
ArrayView<const float> GetConstView() const;
ArrayView<float> GetView();
private:
friend class Pffft;
FloatBuffer(size_t fft_size, FftType fft_type);
const float* const_data() const { return data_; }
float* data() { return data_; }
size_t size() const { return size_; }
const size_t size_;
float* const data_;
};
// TODO(https://crbug.com/webrtc/9577): Consider adding a factory and making
// the ctor private.
// static std::unique_ptr<Pffft> Create(size_t fft_size,
// FftType fft_type); Ctor. `fft_size` must be a supported size (see
// Pffft::IsValidFftSize()). If not supported, the code will crash.
Pffft(size_t fft_size, FftType fft_type);
Pffft(const Pffft&) = delete;
Pffft& operator=(const Pffft&) = delete;
~Pffft();
// Returns true if the FFT size is supported.
static bool IsValidFftSize(size_t fft_size, FftType fft_type);
// Returns true if SIMD code optimizations are being used.
static bool IsSimdEnabled();
// Creates a buffer of the right size.
std::unique_ptr<FloatBuffer> CreateBuffer() const;
// TODO(https://crbug.com/webrtc/9577): Overload with webrtc::ArrayView args.
// Computes the forward fast Fourier transform.
void ForwardTransform(const FloatBuffer& in, FloatBuffer* out, bool ordered);
// Computes the backward fast Fourier transform.
void BackwardTransform(const FloatBuffer& in, FloatBuffer* out, bool ordered);
// Multiplies the frequency components of `fft_x` and `fft_y` and accumulates
// them into `out`. The arrays must have been obtained with
// ForwardTransform(..., /*ordered=*/false) - i.e., `fft_x` and `fft_y` must
// not be ordered.
void FrequencyDomainConvolve(const FloatBuffer& fft_x,
const FloatBuffer& fft_y,
FloatBuffer* out,
float scaling = 1.f);
private:
const size_t fft_size_;
const FftType fft_type_;
PFFFT_Setup* pffft_status_;
float* const scratch_buffer_;
};
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_UTILITY_PFFFT_WRAPPER_H_
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