From 53dd1f3c1a330bab49880f5a044f4b790c85e91a Mon Sep 17 00:00:00 2001
From: Alessio Bazzica <alessiob@webrtc.org>
Date: Tue, 26 Mar 2019 17:27:32 +0100
Subject: [PATCH] PFFFT Wrapper: ordered transform.

Add flag to call either pffft_transform or pffft_transform_ordered.

Bug: webrtc:9577
Change-Id: Ic9af87386264cc5b2baf891a9b4945f58bd3c2ac
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/129761
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Reviewed-by: Yves Gerey <yvesg@webrtc.org>
Reviewed-by: Ivo Creusen <ivoc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27310}
---
 .../audio_processing/utility/pffft_wrapper.cc | 26 ++++++++++++++-----
 .../audio_processing/utility/pffft_wrapper.h  |  4 +--
 .../utility/pffft_wrapper_unittest.cc         |  6 +++--
 3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/modules/audio_processing/utility/pffft_wrapper.cc b/modules/audio_processing/utility/pffft_wrapper.cc
index eb0bff7c58..2361326f25 100644
--- a/modules/audio_processing/utility/pffft_wrapper.cc
+++ b/modules/audio_processing/utility/pffft_wrapper.cc
@@ -91,20 +91,34 @@ std::unique_ptr<Pffft::FloatBuffer> Pffft::CreateBuffer() const {
   return buffer;
 }
 
-void Pffft::ForwardTransform(const FloatBuffer& in, FloatBuffer* out) {
+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_);
-  pffft_transform(pffft_status_, in.const_data(), out->data(), scratch_buffer_,
-                  PFFFT_FORWARD);
+  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) {
+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_);
-  pffft_transform(pffft_status_, in.const_data(), out->data(), scratch_buffer_,
-                  PFFFT_BACKWARD);
+  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);
+  }
 }
 
 }  // namespace webrtc
diff --git a/modules/audio_processing/utility/pffft_wrapper.h b/modules/audio_processing/utility/pffft_wrapper.h
index c1904308bf..a30b97031f 100644
--- a/modules/audio_processing/utility/pffft_wrapper.h
+++ b/modules/audio_processing/utility/pffft_wrapper.h
@@ -69,9 +69,9 @@ class Pffft {
 
   // TODO(https://crbug.com/webrtc/9577): Overload with rtc::ArrayView args.
   // Computes the forward fast Fourier transform.
-  void ForwardTransform(const FloatBuffer& in, FloatBuffer* out);
+  void ForwardTransform(const FloatBuffer& in, FloatBuffer* out, bool ordered);
   // Computes the backward fast Fourier transform.
-  void BackwardTransform(const FloatBuffer& in, FloatBuffer* out);
+  void BackwardTransform(const FloatBuffer& in, FloatBuffer* out, bool ordered);
 
  private:
   const size_t fft_size_;
diff --git a/modules/audio_processing/utility/pffft_wrapper_unittest.cc b/modules/audio_processing/utility/pffft_wrapper_unittest.cc
index 70c5ce52f2..a3d6f357ec 100644
--- a/modules/audio_processing/utility/pffft_wrapper_unittest.cc
+++ b/modules/audio_processing/utility/pffft_wrapper_unittest.cc
@@ -88,7 +88,8 @@ void PffftValidateWrapper(size_t fft_size, bool complex_fft) {
 
   // Forward transform.
   pffft_transform(pffft_status, in, out, scratch, PFFFT_FORWARD);
-  pffft_wrapper.ForwardTransform(*in_wrapper, out_wrapper.get());
+  pffft_wrapper.ForwardTransform(*in_wrapper, out_wrapper.get(),
+                                 /*ordered=*/false);
   ExpectArrayViewsEquality(out_view, out_wrapper_view);
 
   // Copy the FFT results into the input buffers to compute the backward FFT.
@@ -98,7 +99,8 @@ void PffftValidateWrapper(size_t fft_size, bool complex_fft) {
 
   // Backward transform.
   pffft_transform(pffft_status, in, out, scratch, PFFFT_BACKWARD);
-  pffft_wrapper.BackwardTransform(*in_wrapper, out_wrapper.get());
+  pffft_wrapper.BackwardTransform(*in_wrapper, out_wrapper.get(),
+                                  /*ordered=*/false);
   ExpectArrayViewsEquality(out_view, out_wrapper_view);
 
   pffft_destroy_setup(pffft_status);