Finalization of the first version of EchoCanceller 3

webrtc/modules/audio_processing/aec3/aec3_fft.cc

Index: webrtc/modules/audio_processing/aec3/aec3_fft.cc
diff --git a/webrtc/modules/audio_processing/aec3/aec3_fft.cc b/webrtc/modules/audio_processing/aec3/aec3_fft.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3f9ff44e9c84ff144e3cc6a5d27216c0fdeb4295
--- /dev/null
+++ b/webrtc/modules/audio_processing/aec3/aec3_fft.cc
@@ -0,0 +1,42 @@
+/*
+ *  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/aec3_fft.h"
+
+#include <algorithm>
+
+#include "webrtc/base/checks.h"
+
+namespace webrtc {
+
+// TODO(peah): Change x to be std::array once the rest of the code allows this.
+void Aec3Fft::ZeroPaddedFft(rtc::ArrayView<const float> x, FftData* X) const {
+  RTC_DCHECK(X);
+  RTC_DCHECK_EQ(kFftLengthBy2, x.size());
+  std::array<float, kFftLength> fft;
+  std::fill(fft.begin(), fft.begin() + kFftLengthBy2, 0.f);
+  std::copy(x.begin(), x.end(), fft.begin() + kFftLengthBy2);
+  Fft(&fft, X);
+}
+
+void Aec3Fft::PaddedFft(rtc::ArrayView<const float> x,
+                        rtc::ArrayView<float> x_old,
+                        FftData* X) const {
+  RTC_DCHECK(X);
+  RTC_DCHECK_EQ(kFftLengthBy2, x.size());
+  RTC_DCHECK_EQ(kFftLengthBy2, x_old.size());
+  std::array<float, kFftLength> fft;
+  std::copy(x_old.begin(), x_old.end(), fft.begin());
+  std::copy(x.begin(), x.end(), fft.begin() + x_old.size());
+  std::copy(x.begin(), x.end(), x_old.begin());
+  Fft(&fft, X);
+}
+
+}  // namespace webrtc