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 "webrtc/voice_engine/test/auto_test/fakes/loudest_filter.h"
  
  #include "webrtc/base/checks.h"
  
  namespace voetest {
  
  void LoudestFilter::RemoveTimeoutStreams(uint32_t time_ms) {
    auto it = stream_levels_.begin();
    while (it != stream_levels_.end()) {
      if (rtc::TimeDiff(time_ms, it->second.last_time_ms) >
          kStreamTimeOutMs) {
        stream_levels_.erase(it++);
      } else {
        ++it;
      }
    }
  }
  
  unsigned int LoudestFilter::FindQuietestStream() {
    int quietest_level = kInvalidAudioLevel;
    unsigned int quietest_ssrc = 0;
    for (auto stream : stream_levels_) {
      // A smaller value if audio level corresponds to a louder sound.
      if (quietest_level == kInvalidAudioLevel ||
          stream.second.audio_level > quietest_level) {
        quietest_level = stream.second.audio_level;
        quietest_ssrc = stream.first;
      }
    }
    return quietest_ssrc;
  }
  
  bool LoudestFilter::ForwardThisPacket(const webrtc::RTPHeader& rtp_header) {
    uint32_t time_now_ms = rtc::Time();
    RemoveTimeoutStreams(time_now_ms);
  
    int source_ssrc = rtp_header.ssrc;
    int audio_level = rtp_header.extension.hasAudioLevel ?
        rtp_header.extension.audioLevel : kInvalidAudioLevel;
  
    if (audio_level == kInvalidAudioLevel) {
      // Always forward streams with unknown audio level, and don't keep their
      // states.
      return true;
    }
  
    auto it = stream_levels_.find(source_ssrc);
    if (it != stream_levels_.end()) {
      // Stream has been forwarded. Update and continue to forward.
      it->second.audio_level = audio_level;
      it->second.last_time_ms = time_now_ms;
      return true;
    }
  
    if (stream_levels_.size() < kMaxMixSize) {
      stream_levels_[source_ssrc].Set(audio_level, time_now_ms);
      return true;
    }
  
    unsigned int quietest_ssrc = FindQuietestStream();
    RTC_CHECK_NE(0u, quietest_ssrc);
    // A smaller value if audio level corresponds to a louder sound.
    if (audio_level < stream_levels_[quietest_ssrc].audio_level) {
      stream_levels_.erase(quietest_ssrc);
      stream_levels_[source_ssrc].Set(audio_level, time_now_ms);
      return true;
    }
    return false;
  }
  
  }  // namespace voetest
  
  