text: /*
   *  Copyright (c) 2015 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/congestion_controller/rtp/send_time_history.h"
  
  #include <algorithm>
  #include <utility>
  
  #include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
  #include "rtc_base/checks.h"
  #include "system_wrappers/include/clock.h"
  
  namespace webrtc {
  namespace webrtc_cc {
  
  SendTimeHistory::SendTimeHistory(const Clock* clock,
                                   int64_t packet_age_limit_ms)
      : clock_(clock), packet_age_limit_ms_(packet_age_limit_ms) {}
  
  SendTimeHistory::~SendTimeHistory() {}
  
  void SendTimeHistory::AddAndRemoveOld(const PacketFeedback& packet) {
    int64_t now_ms = clock_->TimeInMilliseconds();
    // Remove old.
    while (!history_.empty() &&
           now_ms - history_.begin()->second.creation_time_ms >
               packet_age_limit_ms_) {
      // TODO(sprang): Warn if erasing (too many) old items?
      history_.erase(history_.begin());
    }
  
    // Add new.
    int64_t unwrapped_seq_num = seq_num_unwrapper_.Unwrap(packet.sequence_number);
    PacketFeedback packet_copy = packet;
    packet_copy.long_sequence_number = unwrapped_seq_num;
    history_.insert(std::make_pair(unwrapped_seq_num, packet_copy));
  }
  
  bool SendTimeHistory::OnSentPacket(uint16_t sequence_number,
                                     int64_t send_time_ms) {
    int64_t unwrapped_seq_num = seq_num_unwrapper_.Unwrap(sequence_number);
    auto it = history_.find(unwrapped_seq_num);
    if (it == history_.end())
      return false;
    it->second.send_time_ms = send_time_ms;
    return true;
  }
  
  rtc::Optional<PacketFeedback> SendTimeHistory::GetPacket(
      uint16_t sequence_number) const {
    int64_t unwrapped_seq_num =
        seq_num_unwrapper_.UnwrapWithoutUpdate(sequence_number);
    rtc::Optional<PacketFeedback> optional_feedback;
    auto it = history_.find(unwrapped_seq_num);
    if (it != history_.end())
      optional_feedback.emplace(it->second);
    return optional_feedback;
  }
  
  bool SendTimeHistory::GetFeedback(PacketFeedback* packet_feedback,
                                    bool remove) {
    RTC_DCHECK(packet_feedback);
    int64_t unwrapped_seq_num =
        seq_num_unwrapper_.Unwrap(packet_feedback->sequence_number);
    latest_acked_seq_num_.emplace(
        std::max(unwrapped_seq_num, latest_acked_seq_num_.value_or(0)));
    RTC_DCHECK_GE(*latest_acked_seq_num_, 0);
    auto it = history_.find(unwrapped_seq_num);
    if (it == history_.end())
      return false;
  
    // Save arrival_time not to overwrite it.
    int64_t arrival_time_ms = packet_feedback->arrival_time_ms;
    *packet_feedback = it->second;
    packet_feedback->arrival_time_ms = arrival_time_ms;
  
    if (remove)
      history_.erase(it);
    return true;
  }
  
  size_t SendTimeHistory::GetOutstandingBytes(uint16_t local_net_id,
                                              uint16_t remote_net_id) const {
    size_t outstanding_bytes = 0;
    auto unacked_it = history_.begin();
    if (latest_acked_seq_num_) {
      unacked_it = history_.lower_bound(*latest_acked_seq_num_);
    }
    for (; unacked_it != history_.end(); ++unacked_it) {
      if (unacked_it->second.local_net_id == local_net_id &&
          unacked_it->second.remote_net_id == remote_net_id &&
          unacked_it->second.send_time_ms >= 0) {
        outstanding_bytes += unacked_it->second.payload_size;
      }
    }
    return outstanding_bytes;
  }
  
  }  // namespace webrtc_cc
  }  // namespace webrtc
  