1 files changed, 92 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/video_coding/utility/decoded_frames_history.cc b/third_party/libwebrtc/modules/video_coding/utility/decoded_frames_history.cc
new file mode 100644
index 0000000000..1138aa8448
--- /dev/null
+++ b/third_party/libwebrtc/modules/video_coding/utility/decoded_frames_history.cc
@@ -0,0 +1,92 @@
+/*
+ *  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 "modules/video_coding/utility/decoded_frames_history.h"
+
+#include <algorithm>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+namespace video_coding {
+
+DecodedFramesHistory::DecodedFramesHistory(size_t window_size)
+    : buffer_(window_size) {}
+
+DecodedFramesHistory::~DecodedFramesHistory() = default;
+
+void DecodedFramesHistory::InsertDecoded(int64_t frame_id, uint32_t timestamp) {
+  last_decoded_frame_ = frame_id;
+  last_decoded_frame_timestamp_ = timestamp;
+  int new_index = FrameIdToIndex(frame_id);
+
+  RTC_DCHECK(last_frame_id_ < frame_id);
+
+  // Clears expired values from the cyclic buffer_.
+  if (last_frame_id_) {
+    int64_t id_jump = frame_id - *last_frame_id_;
+    int last_index = FrameIdToIndex(*last_frame_id_);
+
+    if (id_jump >= static_cast<int64_t>(buffer_.size())) {
+      std::fill(buffer_.begin(), buffer_.end(), false);
+    } else if (new_index > last_index) {
+      std::fill(buffer_.begin() + last_index + 1, buffer_.begin() + new_index,
+                false);
+    } else {
+      std::fill(buffer_.begin() + last_index + 1, buffer_.end(), false);
+      std::fill(buffer_.begin(), buffer_.begin() + new_index, false);
+    }
+  }
+
+  buffer_[new_index] = true;
+  last_frame_id_ = frame_id;
+}
+
+bool DecodedFramesHistory::WasDecoded(int64_t frame_id) const {
+  if (!last_frame_id_)
+    return false;
+
+  // Reference to the picture_id out of the stored should happen.
+  if (frame_id <= *last_frame_id_ - static_cast<int64_t>(buffer_.size())) {
+    RTC_LOG(LS_WARNING) << "Referencing a frame out of the window. "
+                           "Assuming it was undecoded to avoid artifacts.";
+    return false;
+  }
+
+  if (frame_id > last_frame_id_)
+    return false;
+
+  return buffer_[FrameIdToIndex(frame_id)];
+}
+
+void DecodedFramesHistory::Clear() {
+  last_decoded_frame_timestamp_.reset();
+  last_decoded_frame_.reset();
+  std::fill(buffer_.begin(), buffer_.end(), false);
+  last_frame_id_.reset();
+}
+
+absl::optional<int64_t> DecodedFramesHistory::GetLastDecodedFrameId() const {
+  return last_decoded_frame_;
+}
+
+absl::optional<uint32_t> DecodedFramesHistory::GetLastDecodedFrameTimestamp()
+    const {
+  return last_decoded_frame_timestamp_;
+}
+
+int DecodedFramesHistory::FrameIdToIndex(int64_t frame_id) const {
+  int m = frame_id % buffer_.size();
+  return m >= 0 ? m : m + buffer_.size();
+}
+
+}  // namespace video_coding
+}  // namespace webrtc