Moving src/webrtc into src/.

In order to eliminate the WebRTC Subtree mirror in Chromium, 
WebRTC is moving the content of the src/webrtc directory up
to the src/ directory.

NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
TBR=tommi@webrtc.org

Bug: chromium:611808
Change-Id: Iac59c5b51b950f174119565bac87955a7994bc38
Reviewed-on: https://webrtc-review.googlesource.com/1560
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19845}

modules/audio_processing/aec3/render_buffer.cc

@@ -0,0 +1,95 @@
+/*
+ *  Copyright (c) 2017 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 "webrtc/modules/audio_processing/aec3/render_buffer.h"
+
+#include <algorithm>
+
+#include "webrtc/modules/audio_processing/aec3/aec3_common.h"
+#include "webrtc/rtc_base/checks.h"
+
+namespace webrtc {
+
+RenderBuffer::RenderBuffer(Aec3Optimization optimization,
+                           size_t num_bands,
+                           size_t num_partitions,
+                           const std::vector<size_t> num_ffts_for_spectral_sums)
+    : optimization_(optimization),
+      fft_buffer_(num_partitions),
+      spectrum_buffer_(num_partitions, std::array<float, kFftLengthBy2Plus1>()),
+      spectral_sums_(num_ffts_for_spectral_sums.size(),
+                     std::array<float, kFftLengthBy2Plus1>()),
+      last_block_(num_bands, std::vector<float>(kBlockSize, 0.f)),
+      fft_() {
+  // Current implementation only allows a maximum of one spectral sum lengths.
+  RTC_DCHECK_EQ(1, num_ffts_for_spectral_sums.size());
+  spectral_sums_length_ = num_ffts_for_spectral_sums[0];
+  RTC_DCHECK_GE(fft_buffer_.size(), spectral_sums_length_);
+
+  Clear();
+}
+
+RenderBuffer::~RenderBuffer() = default;
+
+void RenderBuffer::Clear() {
+  position_ = 0;
+  for (auto& sum : spectral_sums_) {
+    sum.fill(0.f);
+  }
+
+  for (auto& spectrum : spectrum_buffer_) {
+    spectrum.fill(0.f);
+  }
+
+  for (auto& fft : fft_buffer_) {
+    fft.Clear();
+  }
+
+  for (auto& b : last_block_) {
+    std::fill(b.begin(), b.end(), 0.f);
+  }
+}
+
+void RenderBuffer::Insert(const std::vector<std::vector<float>>& block) {
+  // Compute the FFT of the data in the lowest band.
+  FftData X;
+  fft_.PaddedFft(block[0], last_block_[0], &X);
+
+  // Copy the last render frame.
+  RTC_DCHECK_EQ(last_block_.size(), block.size());
+  for (size_t k = 0; k < block.size(); ++k) {
+    RTC_DCHECK_EQ(last_block_[k].size(), block[k].size());
+    std::copy(block[k].begin(), block[k].end(), last_block_[k].begin());
+  }
+
+  // Insert X into the buffer.
+  position_ = position_ > 0 ? position_ - 1 : fft_buffer_.size() - 1;
+  fft_buffer_[position_].Assign(X);
+
+  // Compute and insert the spectrum for the FFT into the spectrum buffer.
+  X.Spectrum(optimization_, &spectrum_buffer_[position_]);
+
+  // Pre-compute and cache the spectral sums.
+  std::copy(spectrum_buffer_[position_].begin(),
+            spectrum_buffer_[position_].end(), spectral_sums_[0].begin());
+  size_t position = (position_ + 1) % fft_buffer_.size();
+  for (size_t j = 1; j < spectral_sums_length_; ++j) {
+    const std::array<float, kFftLengthBy2Plus1>& spectrum =
+        spectrum_buffer_[position];
+
+    for (size_t k = 0; k < spectral_sums_[0].size(); ++k) {
+      spectral_sums_[0][k] += spectrum[k];
+    }
+
+    position = position < (fft_buffer_.size() - 1) ? position + 1 : 0;
+  }
+}
+
+}  // namespace webrtc