1 files changed, 68 insertions, 0 deletions
diff --git a/third_party/libwebrtc/media/engine/unhandled_packets_buffer.cc b/third_party/libwebrtc/media/engine/unhandled_packets_buffer.cc
new file mode 100644
index 0000000000..563712bdf3
--- /dev/null
+++ b/third_party/libwebrtc/media/engine/unhandled_packets_buffer.cc
@@ -0,0 +1,68 @@
+/*
+ *  Copyright (c) 2019 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 "media/engine/unhandled_packets_buffer.h"
+
+#include "absl/algorithm/container.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace cricket {
+
+UnhandledPacketsBuffer::UnhandledPacketsBuffer() {
+  buffer_.reserve(kMaxStashedPackets);
+}
+
+UnhandledPacketsBuffer::~UnhandledPacketsBuffer() = default;
+
+// Store packet in buffer.
+void UnhandledPacketsBuffer::AddPacket(uint32_t ssrc,
+                                       int64_t packet_time_us,
+                                       rtc::CopyOnWriteBuffer packet) {
+  if (buffer_.size() < kMaxStashedPackets) {
+    buffer_.push_back({ssrc, packet_time_us, packet});
+  } else {
+    RTC_DCHECK_LT(insert_pos_, kMaxStashedPackets);
+    buffer_[insert_pos_] = {ssrc, packet_time_us, packet};
+  }
+  insert_pos_ = (insert_pos_ + 1) % kMaxStashedPackets;
+}
+
+// Backfill `consumer` with all stored packet related `ssrcs`.
+void UnhandledPacketsBuffer::BackfillPackets(
+    rtc::ArrayView<const uint32_t> ssrcs,
+    std::function<void(uint32_t, int64_t, rtc::CopyOnWriteBuffer)> consumer) {
+  size_t start;
+  if (buffer_.size() < kMaxStashedPackets) {
+    start = 0;
+  } else {
+    start = insert_pos_;
+  }
+
+  std::vector<PacketWithMetadata> remaining;
+  remaining.reserve(kMaxStashedPackets);
+  for (size_t i = 0; i < buffer_.size(); ++i) {
+    const size_t pos = (i + start) % kMaxStashedPackets;
+
+    // One or maybe 2 ssrcs is expected => loop array instead of more elaborate
+    // scheme.
+    const uint32_t ssrc = buffer_[pos].ssrc;
+    if (absl::c_linear_search(ssrcs, ssrc)) {
+      consumer(ssrc, buffer_[pos].packet_time_us, buffer_[pos].packet);
+    } else {
+      remaining.push_back(buffer_[pos]);
+    }
+  }
+
+  insert_pos_ = 0;  // insert_pos is only used when buffer is full.
+  buffer_.swap(remaining);
+}
+
+}  // namespace cricket