Add TransportFeedbackPacketLossTracker.

webrtc/test/fuzzers/transport_feedback_packet_loss_tracker_fuzzer.cc

+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.

[minyue-webrtc, 2017/01/23 14:29:38]

2017

+ *
+ *  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 <algorithm>
+
+#include "webrtc/base/array_view.h"
+#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
+#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
+#include "webrtc/voice_engine/transport_feedback_packet_loss_tracker.h"
+
+namespace webrtc {
+
+namespace {
+
+using TransportFeedback = rtcp::TransportFeedback;

[kwiberg-webrtc, 2017/01/23 14:04:36]

I'm counting just two uses of this alias. You can probably remove it.

[minyue-webrtc, 2017/01/23 14:29:38]

Done.

+
+class TransportFeedbackGenerator {
+ public:
+  explicit TransportFeedbackGenerator(rtc::ArrayView<const uint8_t> data)
+      : data_(data), ended_(false), data_idx_(0) {}
+
+  void GetNextTransportFeedback(TransportFeedback* feedback) {
+    uint16_t base_seq_num = 0;
+    if (!ReadData<uint16_t>(&base_seq_num)) {
+      return;
+    }
+
+    const int64_t kBaseTimeUs = 1234;  // Irrelevant to this test.
+    feedback->SetBase(base_seq_num, kBaseTimeUs);
+
+    uint16_t num_statuses = 0;
+    if (!ReadData<uint16_t>(&num_statuses))
+      return;
+    num_statuses = std::max<uint16_t>(num_statuses, 1);
+
+    uint16_t seq_num = base_seq_num;
+    while (true) {
+      uint8_t status_byte = 0;
+      if (!ReadData<uint8_t>(&status_byte))
+        return;
+      // Each status byte contains 8 statuses.
+      for (size_t j = 0; j < 8; ++j) {
+        if (status_byte & 0x01) {
+          feedback->AddReceivedPacket(seq_num, kBaseTimeUs);
+        }
+        seq_num++;
+        if (seq_num >= base_seq_num + num_statuses) {
+          feedback->AddReceivedPacket(seq_num, kBaseTimeUs);
+          return;
+        }
+        status_byte >>= 1;
+      }
+    }
+  }
+
+  bool ended() const { return ended_; }
+
+ private:
+  template <typename T>
+  bool ReadData(T* value) {
+    RTC_DCHECK(!ended_);
+    if (data_idx_ + sizeof(T) > data_.size()) {
+      ended_ = true;
+      return false;
+    }
+    *value = ByteReader<T>::ReadBigEndian(&data_[data_idx_]);
+    data_idx_ += sizeof(T);
+    return true;
+  }
+
+  const rtc::ArrayView<const uint8_t> data_;
+  bool ended_;
+  size_t data_idx_;
+};
+
+}  // namespace
+
+void FuzzOneInput(const uint8_t* data, size_t size) {
+  if (size < sizeof(uint32_t)) {
+    return;
+  }
+  constexpr size_t kSeqNumHalf = 0x8000u;
+  const size_t window_size_1 = std::min<size_t>(
+      kSeqNumHalf,
+      std::max<uint16_t>(1, ByteReader<uint16_t>::ReadBigEndian(data)));
+  data += sizeof(uint16_t);
+  const size_t window_size_2 = std::min<size_t>(
+      kSeqNumHalf,
+      std::max<uint16_t>(1, ByteReader<uint16_t>::ReadBigEndian(data)));
+  data += sizeof(uint16_t);
+  size -= 2 * sizeof(uint16_t);
+
+  TransportFeedbackPacketLossTracker tracker(
+      std::min(window_size_1, window_size_2),
+      std::max(window_size_1, window_size_2));
+  TransportFeedbackGenerator feedback_generator(
+      rtc::ArrayView<const uint8_t>(data, size));
+  while (!feedback_generator.ended()) {
+    TransportFeedback feedback;
+    feedback_generator.GetNextTransportFeedback(&feedback);
+    tracker.OnReceivedTransportFeedback(feedback);
+    tracker.Validate();
+  }
+}
+
+}  // namespace webrtc