Added first layer of the echo canceller 3 functionality

webrtc/modules/audio_processing/aec3/frame_blocker.cc

Index: webrtc/modules/audio_processing/aec3/frame_blocker.cc
diff --git a/webrtc/modules/audio_processing/aec3/frame_blocker.cc b/webrtc/modules/audio_processing/aec3/frame_blocker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b15b45438478a4deed8977d746151805b815be49
--- /dev/null
+++ b/webrtc/modules/audio_processing/aec3/frame_blocker.cc
@@ -0,0 +1,72 @@
+/*
+ *  Copyright (c) 2016 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/frame_blocker.h"
+
+#include <algorithm>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
+
+namespace webrtc {
+
+FrameBlocker::FrameBlocker(size_t num_bands)
+    : num_bands_(num_bands), buffer_(num_bands_) {
+  for (auto& b : buffer_) {
+    b.reserve(kBlockSize);
+    RTC_DCHECK(b.empty());
+  }
+}
+
+FrameBlocker::~FrameBlocker() = default;
+
+void FrameBlocker::InsertSubFrameAndExtractBlock(
+    const std::vector<rtc::ArrayView<float>>& sub_frame,
+    std::vector<std::vector<float>>* block) {
+  RTC_DCHECK(block);
+  RTC_DCHECK_EQ(num_bands_, block->size());
+  RTC_DCHECK_EQ(num_bands_, sub_frame.size());
+  for (size_t i = 0; i < num_bands_; ++i) {
+    RTC_DCHECK_GE(kBlockSize - 16, buffer_[i].size());
+    RTC_DCHECK_EQ(kBlockSize, (*block)[i].size());
+    RTC_DCHECK_EQ(kSubFrameLength, sub_frame[i].size());
+    const int samples_to_block = kBlockSize - buffer_[i].size();
+    (*block)[i].clear();
+    (*block)[i].insert((*block)[i].begin(), buffer_[i].begin(),
+                       buffer_[i].end());
+    (*block)[i].insert((*block)[i].begin() + buffer_[i].size(),
+                       sub_frame[i].begin(),
+                       sub_frame[i].begin() + samples_to_block);
+    buffer_[i].clear();
+    buffer_[i].insert(buffer_[i].begin(),
+                      sub_frame[i].begin() + samples_to_block,
+                      sub_frame[i].end());
+  }
+}
+
+bool FrameBlocker::IsBlockAvailable() const {
+  return kBlockSize == buffer_[0].size();
+}
+
+void FrameBlocker::ExtractBlock(std::vector<std::vector<float>>* block) {
+  RTC_DCHECK(block);
+  RTC_DCHECK_EQ(num_bands_, block->size());
+  RTC_DCHECK(IsBlockAvailable());
+  for (size_t i = 0; i < num_bands_; ++i) {
+    RTC_DCHECK_EQ(kBlockSize, buffer_[i].size());
+    RTC_DCHECK_EQ(kBlockSize, (*block)[i].size());
+    (*block)[i].clear();
+    (*block)[i].insert((*block)[i].begin(), buffer_[i].begin(),
+                       buffer_[i].end());
+    buffer_[i].clear();
+  }
+}
+
+}  // namespace webrtc