Move webrtc/{base => rtc_base}

webrtc/base/rate_statistics.cc

-/*
- *  Copyright (c) 2013 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/base/rate_statistics.h"
-
-#include <algorithm>
-
-#include "webrtc/base/checks.h"
-
-namespace webrtc {
-
-RateStatistics::RateStatistics(int64_t window_size_ms, float scale)
-    : buckets_(new Bucket[window_size_ms]()),
-      accumulated_count_(0),
-      num_samples_(0),
-      oldest_time_(-window_size_ms),
-      oldest_index_(0),
-      scale_(scale),
-      max_window_size_ms_(window_size_ms),
-      current_window_size_ms_(max_window_size_ms_) {}
-
-RateStatistics::~RateStatistics() {}
-
-void RateStatistics::Reset() {
-  accumulated_count_ = 0;
-  num_samples_ = 0;
-  oldest_time_ = -max_window_size_ms_;
-  oldest_index_ = 0;
-  current_window_size_ms_ = max_window_size_ms_;
-  for (int64_t i = 0; i < max_window_size_ms_; i++)
-    buckets_[i] = Bucket();
-}
-
-void RateStatistics::Update(size_t count, int64_t now_ms) {
-  if (now_ms < oldest_time_) {
-    // Too old data is ignored.
-    return;
-  }
-
-  EraseOld(now_ms);
-
-  // First ever sample, reset window to start now.
-  if (!IsInitialized())
-    oldest_time_ = now_ms;
-
-  uint32_t now_offset = static_cast<uint32_t>(now_ms - oldest_time_);
-  RTC_DCHECK_LT(now_offset, max_window_size_ms_);
-  uint32_t index = oldest_index_ + now_offset;
-  if (index >= max_window_size_ms_)
-    index -= max_window_size_ms_;
-  buckets_[index].sum += count;
-  ++buckets_[index].samples;
-  accumulated_count_ += count;
-  ++num_samples_;
-}
-
-rtc::Optional<uint32_t> RateStatistics::Rate(int64_t now_ms) const {
-  // Yeah, this const_cast ain't pretty, but the alternative is to declare most
-  // of the members as mutable...
-  const_cast<RateStatistics*>(this)->EraseOld(now_ms);
-
-  // If window is a single bucket or there is only one sample in a data set that
-  // has not grown to the full window size, treat this as rate unavailable.
-  int64_t active_window_size = now_ms - oldest_time_ + 1;
-  if (num_samples_ == 0 || active_window_size <= 1 ||
-      (num_samples_ <= 1 && active_window_size < current_window_size_ms_)) {
-    return rtc::Optional<uint32_t>();
-  }
-
-  float scale = scale_ / active_window_size;
-  return rtc::Optional<uint32_t>(
-      static_cast<uint32_t>(accumulated_count_ * scale + 0.5f));
-}
-
-void RateStatistics::EraseOld(int64_t now_ms) {
-  if (!IsInitialized())
-    return;
-
-  // New oldest time that is included in data set.
-  int64_t new_oldest_time = now_ms - current_window_size_ms_ + 1;
-
-  // New oldest time is older than the current one, no need to cull data.
-  if (new_oldest_time <= oldest_time_)
-    return;
-
-  // Loop over buckets and remove too old data points.
-  while (num_samples_ > 0 && oldest_time_ < new_oldest_time) {
-    const Bucket& oldest_bucket = buckets_[oldest_index_];
-    RTC_DCHECK_GE(accumulated_count_, oldest_bucket.sum);
-    RTC_DCHECK_GE(num_samples_, oldest_bucket.samples);
-    accumulated_count_ -= oldest_bucket.sum;
-    num_samples_ -= oldest_bucket.samples;
-    buckets_[oldest_index_] = Bucket();
-    if (++oldest_index_ >= max_window_size_ms_)
-      oldest_index_ = 0;
-    ++oldest_time_;
-  }
-  oldest_time_ = new_oldest_time;
-}
-
-bool RateStatistics::SetWindowSize(int64_t window_size_ms, int64_t now_ms) {
-  if (window_size_ms <= 0 || window_size_ms > max_window_size_ms_)
-    return false;
-
-  current_window_size_ms_ = window_size_ms;
-  EraseOld(now_ms);
-  return true;
-}
-
-bool RateStatistics::IsInitialized() const {
-  return oldest_time_ != -max_window_size_ms_;
-}
-
-}  // namespace webrtc