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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.
*/
#include "modules/audio_processing/utility/pffft_wrapper.h"
#include "rtc_base/checks.h"
#include "third_party/pffft/src/pffft.h"
namespace webrtc {
namespace {
size_t GetBufferSize(size_t fft_size, Pffft::FftType fft_type) {
return fft_size * (fft_type == Pffft::FftType::kReal ? 1 : 2);
}
float* AllocatePffftBuffer(size_t size) {
return static_cast<float*>(pffft_aligned_malloc(size * sizeof(float)));
}
} // namespace
Pffft::FloatBuffer::FloatBuffer(size_t fft_size, FftType fft_type)
: size_(GetBufferSize(fft_size, fft_type)),
data_(AllocatePffftBuffer(size_)) {}
Pffft::FloatBuffer::~FloatBuffer() {
pffft_aligned_free(data_);
}
ArrayView<const float> Pffft::FloatBuffer::GetConstView() const {
return {data_, size_};
}
ArrayView<float> Pffft::FloatBuffer::GetView() {
return {data_, size_};
}
Pffft::Pffft(size_t fft_size, FftType fft_type)
: fft_size_(fft_size),
fft_type_(fft_type),
pffft_status_(pffft_new_setup(
fft_size_,
fft_type == Pffft::FftType::kReal ? PFFFT_REAL : PFFFT_COMPLEX)),
scratch_buffer_(
AllocatePffftBuffer(GetBufferSize(fft_size_, fft_type_))) {
RTC_DCHECK(pffft_status_);
RTC_DCHECK(scratch_buffer_);
}
Pffft::~Pffft() {
pffft_destroy_setup(pffft_status_);
pffft_aligned_free(scratch_buffer_);
}
bool Pffft::IsValidFftSize(size_t fft_size, FftType fft_type) {
if (fft_size == 0) {
return false;
}
// PFFFT only supports transforms for inputs of length N of the form
// N = (2^a)*(3^b)*(5^c) where b >=0 and c >= 0 and a >= 5 for the real FFT
// and a >= 4 for the complex FFT.
constexpr int kFactors[] = {2, 3, 5};
int factorization[] = {0, 0, 0};
int n = static_cast<int>(fft_size);
for (int i = 0; i < 3; ++i) {
while (n % kFactors[i] == 0) {
n = n / kFactors[i];
factorization[i]++;
}
}
int a_min = (fft_type == Pffft::FftType::kReal) ? 5 : 4;
return factorization[0] >= a_min && n == 1;
}
bool Pffft::IsSimdEnabled() {
return pffft_simd_size() > 1;
}
std::unique_ptr<Pffft::FloatBuffer> Pffft::CreateBuffer() const {
// Cannot use make_unique from absl because Pffft is the only friend of
// Pffft::FloatBuffer.
std::unique_ptr<Pffft::FloatBuffer> buffer(
new Pffft::FloatBuffer(fft_size_, fft_type_));
return buffer;
}
void Pffft::ForwardTransform(const FloatBuffer& in,
FloatBuffer* out,
bool ordered) {
RTC_DCHECK_EQ(in.size(), GetBufferSize(fft_size_, fft_type_));
RTC_DCHECK_EQ(in.size(), out->size());
RTC_DCHECK(scratch_buffer_);
if (ordered) {
pffft_transform_ordered(pffft_status_, in.const_data(), out->data(),
scratch_buffer_, PFFFT_FORWARD);
} else {
pffft_transform(pffft_status_, in.const_data(), out->data(),
scratch_buffer_, PFFFT_FORWARD);
}
}
void Pffft::BackwardTransform(const FloatBuffer& in,
FloatBuffer* out,
bool ordered) {
RTC_DCHECK_EQ(in.size(), GetBufferSize(fft_size_, fft_type_));
RTC_DCHECK_EQ(in.size(), out->size());
RTC_DCHECK(scratch_buffer_);
if (ordered) {
pffft_transform_ordered(pffft_status_, in.const_data(), out->data(),
scratch_buffer_, PFFFT_BACKWARD);
} else {
pffft_transform(pffft_status_, in.const_data(), out->data(),
scratch_buffer_, PFFFT_BACKWARD);
}
}
void Pffft::FrequencyDomainConvolve(const FloatBuffer& fft_x,
const FloatBuffer& fft_y,
FloatBuffer* out,
float scaling) {
RTC_DCHECK_EQ(fft_x.size(), GetBufferSize(fft_size_, fft_type_));
RTC_DCHECK_EQ(fft_x.size(), fft_y.size());
RTC_DCHECK_EQ(fft_x.size(), out->size());
pffft_zconvolve_accumulate(pffft_status_, fft_x.const_data(),
fft_y.const_data(), out->data(), scaling);
}
} // namespace webrtc
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