Add support for transport wide sequence numbers

webrtc/modules/bitrate_controller/send_time_history.cc

-/*
- *  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 <assert.h>
-
-#include "webrtc/modules/bitrate_controller/send_time_history.h"
-
-namespace webrtc {
-
-SendTimeHistory::SendTimeHistory(int64_t packet_age_limit)
-    : packet_age_limit_(packet_age_limit), oldest_sequence_number_(0) {
-}
-
-SendTimeHistory::~SendTimeHistory() {
-}
-
-void SendTimeHistory::Clear() {
-  history_.clear();
-}
-
-void SendTimeHistory::AddAndRemoveOldSendTimes(uint16_t sequence_number,
-                                               int64_t timestamp) {
-  EraseOld(timestamp - packet_age_limit_);
-
-  if (history_.empty())
-    oldest_sequence_number_ = sequence_number;
-
-  history_[sequence_number] = timestamp;
-}
-
-void SendTimeHistory::EraseOld(int64_t limit) {
-  while (!history_.empty()) {
-    auto it = history_.find(oldest_sequence_number_);
-    assert(it != history_.end());
-
-    if (it->second > limit)
-      return;  // Oldest packet within age limit, return.
-
-    // TODO(sprang): Warn if erasing (too many) old items?
-    history_.erase(it);
-    UpdateOldestSequenceNumber();
-  }
-}
-
-void SendTimeHistory::UpdateOldestSequenceNumber() {
-  // After removing an element from the map, update oldest_sequence_number_ to
-  // the element with the lowest sequence number higher than the previous
-  // value (there might be gaps).
-  if (history_.empty())
-    return;
-  auto it = history_.upper_bound(oldest_sequence_number_);
-  if (it == history_.end()) {
-    // No element with higher sequence number than oldest_sequence_number_
-    // found, check wrap around. Note that history_.upper_bound(0) will not
-    // find 0 even if it is there, need to explicitly check for 0.
-    it = history_.find(0);
-    if (it == history_.end())
-      it = history_.upper_bound(0);
-  }
-  assert(it != history_.end());
-  oldest_sequence_number_ = it->first;
-}
-
-bool SendTimeHistory::GetSendTime(uint16_t sequence_number,
-                                  int64_t* timestamp,
-                                  bool remove) {
-  auto it = history_.find(sequence_number);
-  if (it == history_.end())
-    return false;
-  *timestamp = it->second;
-  if (remove) {
-    history_.erase(it);
-    if (sequence_number == oldest_sequence_number_)
-      UpdateOldestSequenceNumber();
-  }
-  return true;
-}
-
-}  // namespace webrtc