Home | History | Annotate | Download | only in remote_bitrate_estimator 
      1 /*
      2  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include <assert.h>
     12 
     13 #include "webrtc/modules/remote_bitrate_estimator/include/send_time_history.h"
     14 
     15 namespace webrtc {
     16 
     17 SendTimeHistory::SendTimeHistory(Clock* clock, int64_t packet_age_limit)
     18     : clock_(clock),
     19       packet_age_limit_(packet_age_limit),
     20       oldest_sequence_number_(0) {}
     21 
     22 SendTimeHistory::~SendTimeHistory() {
     23 }
     24 
     25 void SendTimeHistory::Clear() {
     26   history_.clear();
     27 }
     28 
     29 void SendTimeHistory::AddAndRemoveOld(uint16_t sequence_number,
     30                                       size_t length,
     31                                       bool was_paced) {
     32   EraseOld();
     33 
     34   if (history_.empty())
     35     oldest_sequence_number_ = sequence_number;
     36 
     37   history_.insert(std::pair<uint16_t, PacketInfo>(
     38       sequence_number, PacketInfo(clock_->TimeInMilliseconds(), 0, -1,
     39                                   sequence_number, length, was_paced)));
     40 }
     41 
     42 bool SendTimeHistory::OnSentPacket(uint16_t sequence_number,
     43                                    int64_t send_time_ms) {
     44   auto it = history_.find(sequence_number);
     45   if (it == history_.end())
     46     return false;
     47   it->second.send_time_ms = send_time_ms;
     48   return true;
     49 }
     50 
     51 void SendTimeHistory::EraseOld() {
     52   while (!history_.empty()) {
     53     auto it = history_.find(oldest_sequence_number_);
     54     assert(it != history_.end());
     55 
     56     if (clock_->TimeInMilliseconds() - it->second.creation_time_ms <=
     57         packet_age_limit_) {
     58       return;  // Oldest packet within age limit, return.
     59     }
     60 
     61     // TODO(sprang): Warn if erasing (too many) old items?
     62     history_.erase(it);
     63     UpdateOldestSequenceNumber();
     64   }
     65 }
     66 
     67 void SendTimeHistory::UpdateOldestSequenceNumber() {
     68   // After removing an element from the map, update oldest_sequence_number_ to
     69   // the element with the lowest sequence number higher than the previous
     70   // value (there might be gaps).
     71   if (history_.empty())
     72     return;
     73   auto it = history_.upper_bound(oldest_sequence_number_);
     74   if (it == history_.end()) {
     75     // No element with higher sequence number than oldest_sequence_number_
     76     // found, check wrap around. Note that history_.upper_bound(0) will not
     77     // find 0 even if it is there, need to explicitly check for 0.
     78     it = history_.find(0);
     79     if (it == history_.end())
     80       it = history_.upper_bound(0);
     81   }
     82   assert(it != history_.end());
     83   oldest_sequence_number_ = it->first;
     84 }
     85 
     86 bool SendTimeHistory::GetInfo(PacketInfo* packet, bool remove) {
     87   auto it = history_.find(packet->sequence_number);
     88   if (it == history_.end())
     89     return false;
     90   int64_t receive_time = packet->arrival_time_ms;
     91   *packet = it->second;
     92   packet->arrival_time_ms = receive_time;
     93   if (remove) {
     94     history_.erase(it);
     95     if (packet->sequence_number == oldest_sequence_number_)
     96       UpdateOldestSequenceNumber();
     97   }
     98   return true;
     99 }
    100 
    101 }  // namespace webrtc
    102