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f2737d23d1
Bug: webrtc:163 Change-Id: I318982ee549fe71cd48f74cdfad4173506742411 Reviewed-on: https://webrtc-review.googlesource.com/17040 Commit-Queue: Steve Anton <steveanton@webrtc.org> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Cr-Commit-Position: refs/heads/master@{#20509}
87 lines
2.9 KiB
C++
87 lines
2.9 KiB
C++
/*
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* Copyright 2017 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef P2P_BASE_PACKETLOSSESTIMATOR_H_
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#define P2P_BASE_PACKETLOSSESTIMATOR_H_
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#include <stdint.h>
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#include <string>
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#include <unordered_map>
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namespace cricket {
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// Estimates the response rate for a series of messages expecting responses.
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// Messages and their corresponding responses are identified by a string id.
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//
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// Responses are considered lost if they are not received within
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// |consider_lost_after_ms|. If a response is received after
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// |consider_lost_after_ms|, it is still considered as a response.
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// Messages sent more than |forget_after_ms| ago are not considered
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// anymore. The response rate is initially assumed to be 1.0.
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//
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// If the current time is 7, |forget_after_ms| is 6, and
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// |consider_lost_after_ms| is 2, the response rate considers messages sent
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// between times 1 and 5, so only messages in the following window can be
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// considered lost:
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//
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// Time: 0 1 2 3 4 5 6 7
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// Wind: <-------> |
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//
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// Responses received to the right of the window are still counted.
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class PacketLossEstimator {
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public:
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explicit PacketLossEstimator(int64_t consider_lost_after_ms,
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int64_t forget_after_ms);
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~PacketLossEstimator();
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// Registers that a message with the given |id| was sent at |sent_time|.
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void ExpectResponse(std::string id, int64_t sent_time);
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// Registers a response with the given |id| was received at |received_time|.
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void ReceivedResponse(std::string id, int64_t received_time);
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// Calculates the current response rate based on the expected and received
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// messages. Messages sent more than |forget_after| ms ago will be forgotten.
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void UpdateResponseRate(int64_t now);
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// Gets the current response rate as updated by UpdateResponseRate.
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double get_response_rate() const { return response_rate_; }
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std::size_t tracked_packet_count_for_testing() const;
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// Output tracked packet state as a string.
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std::string TrackedPacketsStringForTesting(std::size_t max) const;
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private:
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struct PacketInfo {
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int64_t sent_time;
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bool response_received;
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};
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// Called periodically by ExpectResponse and ReceivedResponse to manage memory
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// usage.
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void MaybeForgetOldRequests(int64_t now);
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bool ConsiderLost(const PacketInfo&, int64_t now) const;
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bool Forget(const PacketInfo&, int64_t now) const;
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int64_t consider_lost_after_ms_;
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int64_t forget_after_ms_;
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int64_t last_forgot_at_ = 0;
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std::unordered_map<std::string, PacketInfo> tracked_packets_;
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double response_rate_ = 1.0;
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};
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} // namespace cricket
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#endif // P2P_BASE_PACKETLOSSESTIMATOR_H_
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