Adding second layer of the echo canceller 3 functionality.

webrtc/modules/audio_processing/aec3/render_delay_buffer.cc

Index: webrtc/modules/audio_processing/aec3/render_delay_buffer.cc
diff --git a/webrtc/modules/audio_processing/aec3/render_delay_buffer.cc b/webrtc/modules/audio_processing/aec3/render_delay_buffer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8794772c105496a174239e1011c1a4b0348b53c7
--- /dev/null
+++ b/webrtc/modules/audio_processing/aec3/render_delay_buffer.cc
@@ -0,0 +1,101 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.

[hlundin-webrtc, 2017/01/18 13:08:49]

2017

[peah-webrtc, 2017/01/19 15:33:06]

Done.

+ *
+ *  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_delay_buffer.h"
+
+#include <string.h>
+#include <algorithm>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
+#include "webrtc/system_wrappers/include/logging.h"
+
+namespace webrtc {
+namespace {
+
+class RenderDelayBufferImpl final : public RenderDelayBuffer {
+ public:
+  RenderDelayBufferImpl(size_t size_blocks,
+                        size_t num_bands,
+                        size_t max_api_jitter_blocks);
+  ~RenderDelayBufferImpl() override;
+
+  bool Insert(std::vector<std::vector<float>>* block) override;
+  const std::vector<std::vector<float>>& GetNext() override;
+  void SetDelay(size_t delay) override;
+  size_t Delay() const override { return delay_; }
+  size_t MaxDelay() const override {
+    return buffer_.size() - max_api_jitter_blocks_;
+  }
+  bool IsBlockAvailable() const override { return insert_surplus_ > 0; }
+  size_t MaxApiJitter() const override { return max_api_jitter_blocks_; }
+
+ private:
+  const size_t max_api_jitter_blocks_;
+  std::vector<std::vector<std::vector<float>>> buffer_;

[hlundin-webrtc, 2017/01/18 13:08:50]

<inception meme> A vector of vectors of vectors... </inception meme>
:)

[peah-webrtc, 2017/01/19 15:33:06]

:-D Yes, it is almost like a 5D world.

+  int last_insert_index_ = 0;

[hlundin-webrtc, 2017/01/18 13:08:50]

Shouldn't this be size_t?

[peah-webrtc, 2017/01/19 15:33:05]

Done.

+  size_t delay_ = 0;
+  size_t insert_surplus_ = 0;
+
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RenderDelayBufferImpl);
+};
+
+RenderDelayBufferImpl::RenderDelayBufferImpl(size_t size_blocks,
+                                             size_t num_bands,
+                                             size_t max_api_jitter_blocks)
+    : max_api_jitter_blocks_(max_api_jitter_blocks),
+      buffer_(size_blocks + max_api_jitter_blocks_,
+              std::vector<std::vector<float>>(
+                  num_bands,
+                  std::vector<float>(kBlockSize, 0.f))) {}
+
+RenderDelayBufferImpl::~RenderDelayBufferImpl() = default;
+
+bool RenderDelayBufferImpl::Insert(std::vector<std::vector<float>>* block) {
+  RTC_DCHECK_EQ(block->size(), buffer_[0].size());
+  RTC_DCHECK_EQ((*block)[0].size(), buffer_[0][0].size());
+
+  if (insert_surplus_ == max_api_jitter_blocks_) {
+    return false;
+  }
+  last_insert_index_ = (last_insert_index_ + 1) % buffer_.size();
+  block->swap(buffer_[last_insert_index_]);
+
+  ++insert_surplus_;
+
+  return true;
+}
+
+const std::vector<std::vector<float>>& RenderDelayBufferImpl::GetNext() {
+  RTC_DCHECK(IsBlockAvailable());

[hlundin-webrtc, 2017/01/18 13:08:49]

I gather it is the caller's responsibility to make sure that there is a block
available before calling GetNext. Better document that in the h file.

[peah-webrtc, 2017/01/19 15:33:05]

Done.

+  const int extract_index_ =

[hlundin-webrtc, 2017/01/18 13:08:49]

size_t?

[peah-webrtc, 2017/01/19 15:33:05]

Done.

+      (last_insert_index_ - delay_ - insert_surplus_ + 1 + buffer_.size()) %
+      buffer_.size();

[hlundin-webrtc, 2017/01/18 13:08:49]

DCHECK that extract_index ends up in the valid range.

[peah-webrtc, 2017/01/19 15:33:05]

Done.

+  RTC_DCHECK_LT(0, insert_surplus_);
+  --insert_surplus_;
+  return buffer_[extract_index_];
+}
+
+void RenderDelayBufferImpl::SetDelay(size_t delay) {
+  RTC_DCHECK_GE(MaxDelay(), delay);

[hlundin-webrtc, 2017/01/18 13:08:49]

Also the caller's responsibility. Document in h file.

[peah-webrtc, 2017/01/19 15:33:05]

Done.

+  delay_ = delay;
+}
+
+}  // namespace
+
+RenderDelayBuffer* RenderDelayBuffer::Create(size_t size_blocks,
+                                             size_t num_bands,
+                                             size_t max_api_jitter_blocks) {
+  return new RenderDelayBufferImpl(size_blocks, num_bands,
+                                   max_api_jitter_blocks);
+}
+
+}  // namespace webrtc