Added implementation of three classes in BBR,with unit-tests.

webrtc/modules/remote_bitrate_estimator/test/estimators/max_bandwidth_filter.cc

 /*
  *  Copyright (c) 2017 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 "webrtc/modules/remote_bitrate_estimator/test/estimators/max_bandwidth_filter.h"
 
 namespace webrtc {
 namespace testing {
 namespace bwe {
 MaxBandwidthFilter::MaxBandwidthFilter()
     : bandwidth_last_round_bytes_per_ms_(0),
-      round_bandwidth_updated_(0),
-      max_bandwidth_estimate_bytes_per_ms_(0),
+      max_bandwidth_estimate_bps_(0),
       rounds_without_growth_(0) {}
 
 MaxBandwidthFilter::~MaxBandwidthFilter() {}
 
 // Rounds are units for packets rtt_time, after packet has been acknowledged,
 // one round has passed from its send time.
-void MaxBandwidthFilter::AddBandwidthSample(int64_t sample_bytes_per_ms,
+void MaxBandwidthFilter::AddBandwidthSample(int64_t sample_bps,
                                             int64_t round,
                                             size_t filter_size_round) {
-  if (round - round_bandwidth_updated_ >= filter_size_round ||
-      sample_bytes_per_ms >= max_bandwidth_estimate_bytes_per_ms_) {
-    max_bandwidth_estimate_bytes_per_ms_ = sample_bytes_per_ms;
-    round_bandwidth_updated_ = round;
+  if (bandwidth_samples_[0].first == 0 ||
+      sample_bps >= bandwidth_samples_[0].first ||
+      round - bandwidth_samples_[2].second >= filter_size_round)
+    bandwidth_samples_[0] = bandwidth_samples_[1] =
+        bandwidth_samples_[2] = {sample_bps, round};
+  if (sample_bps >= bandwidth_samples_[1].first) {
+    bandwidth_samples_[1] = {sample_bps, round};
+    bandwidth_samples_[2] = bandwidth_samples_[1];
+  } else {
+    if (sample_bps >= bandwidth_samples_[1].first)
+      bandwidth_samples_[2] = {sample_bps, round};
   }
+  if (round - bandwidth_samples_[0].second >= filter_size_round) {
+    bandwidth_samples_[0] = bandwidth_samples_[1];
+    bandwidth_samples_[1] = bandwidth_samples_[2];
+    bandwidth_samples_[2] = {sample_bps, round};
+    if (round - bandwidth_samples_[0].second >= filter_size_round) {
+      bandwidth_samples_[0] = bandwidth_samples_[1];
+      bandwidth_samples_[1] = bandwidth_samples_[2];
+    }
+    max_bandwidth_estimate_bps_ = bandwidth_samples_[0].first;
+    return;
+  }
+  if (bandwidth_samples_[1].first == bandwidth_samples_[0].first &&
+      round - bandwidth_samples_[1].second > filter_size_round / 4) {
+    bandwidth_samples_[2] = bandwidth_samples_[1] = {sample_bps, round};
+    max_bandwidth_estimate_bps_ = bandwidth_samples_[0].first;
+    return;
+  }
+  if (bandwidth_samples_[2].first == bandwidth_samples_[1].first &&
+      round - bandwidth_samples_[2].second > filter_size_round / 2)
+    bandwidth_samples_[2] = {sample_bps, round};
+  max_bandwidth_estimate_bps_ = bandwidth_samples_[0].first;
 }
 
 bool MaxBandwidthFilter::FullBandwidthReached(float growth_target,
                                               int max_rounds_without_growth) {
   // Minimal bandwidth necessary to assume that better bandwidth can still be
   // found and full bandwidth is not reached.
   int64_t minimal_bandwidth =
       bandwidth_last_round_bytes_per_ms_ * growth_target;
-  if (max_bandwidth_estimate_bytes_per_ms_ >= minimal_bandwidth) {
-    bandwidth_last_round_bytes_per_ms_ = max_bandwidth_estimate_bytes_per_ms_;
+  if (max_bandwidth_estimate_bps_ >= minimal_bandwidth) {
+    bandwidth_last_round_bytes_per_ms_ = max_bandwidth_estimate_bps_;
     rounds_without_growth_ = 0;
     return false;
   }
   rounds_without_growth_++;
   return rounds_without_growth_ >= max_rounds_without_growth;
 }
 }  // namespace bwe
 }  // namespace testing
 }  // namespace webrtc