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PiperOrigin-RevId: 237361882
Change-Id: I109a68f44db867b20f8c6a7732b0ce657133e52a

quic/core/quic_sustained_bandwidth_recorder.cc

diff --git a/quic/core/quic_sustained_bandwidth_recorder.cc b/quic/core/quic_sustained_bandwidth_recorder.cc
new file mode 100644
index 0000000..dd94a34
--- /dev/null
+++ b/quic/core/quic_sustained_bandwidth_recorder.cc
@@ -0,0 +1,62 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/third_party/quiche/src/quic/core/quic_sustained_bandwidth_recorder.h"
+
+#include "net/third_party/quiche/src/quic/core/quic_bandwidth.h"
+#include "net/third_party/quiche/src/quic/core/quic_time.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
+
+namespace quic {
+
+QuicSustainedBandwidthRecorder::QuicSustainedBandwidthRecorder()
+    : has_estimate_(false),
+      is_recording_(false),
+      bandwidth_estimate_recorded_during_slow_start_(false),
+      bandwidth_estimate_(QuicBandwidth::Zero()),
+      max_bandwidth_estimate_(QuicBandwidth::Zero()),
+      max_bandwidth_timestamp_(0),
+      start_time_(QuicTime::Zero()) {}
+
+void QuicSustainedBandwidthRecorder::RecordEstimate(bool in_recovery,
+                                                    bool in_slow_start,
+                                                    QuicBandwidth bandwidth,
+                                                    QuicTime estimate_time,
+                                                    QuicWallTime wall_time,
+                                                    QuicTime::Delta srtt) {
+  if (in_recovery) {
+    is_recording_ = false;
+    QUIC_DVLOG(1) << "Stopped recording at: "
+                  << estimate_time.ToDebuggingValue();
+    return;
+  }
+
+  if (!is_recording_) {
+    // This is the first estimate of a new recording period.
+    start_time_ = estimate_time;
+    is_recording_ = true;
+    QUIC_DVLOG(1) << "Started recording at: " << start_time_.ToDebuggingValue();
+    return;
+  }
+
+  // If we have been recording for at least 3 * srtt, then record the latest
+  // bandwidth estimate as a valid sustained bandwidth estimate.
+  if (estimate_time - start_time_ >= 3 * srtt) {
+    has_estimate_ = true;
+    bandwidth_estimate_recorded_during_slow_start_ = in_slow_start;
+    bandwidth_estimate_ = bandwidth;
+    QUIC_DVLOG(1) << "New sustained bandwidth estimate (KBytes/s): "
+                  << bandwidth_estimate_.ToKBytesPerSecond();
+  }
+
+  // Check for an increase in max bandwidth.
+  if (bandwidth > max_bandwidth_estimate_) {
+    max_bandwidth_estimate_ = bandwidth;
+    max_bandwidth_timestamp_ = wall_time.ToUNIXSeconds();
+    QUIC_DVLOG(1) << "New max bandwidth estimate (KBytes/s): "
+                  << max_bandwidth_estimate_.ToKBytesPerSecond();
+  }
+}
+
+}  // namespace quic