8c68845090
Variance calculation isn't currently used but overflow checks there may cause unnecessary crash. Instead of completely deleting useful feature it's now easy to disable it by choosing an appropriate Counter class. Bug: None Change-Id: Ifa8bbf2d023553504caa768e08e59ebccfb2fbb4 Reviewed-on: https://webrtc-review.googlesource.com/99561 Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org> Cr-Commit-Position: refs/heads/master@{#24699}
98 lines
2.9 KiB
C++
98 lines
2.9 KiB
C++
/*
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* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include <limits>
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#include "rtc_base/checks.h"
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#include "rtc_base/numerics/safe_conversions.h"
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#include "rtc_base/numerics/sample_counter.h"
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namespace rtc {
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SampleCounter::SampleCounter() = default;
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SampleCounter::~SampleCounter() = default;
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void SampleCounter::Add(int sample) {
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if (sum_ > 0) {
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RTC_DCHECK_LE(sample, std::numeric_limits<int64_t>::max() - sum_);
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} else {
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RTC_DCHECK_GE(sample, std::numeric_limits<int64_t>::min() - sum_);
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}
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sum_ += sample;
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++num_samples_;
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if (!max_ || sample > *max_) {
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max_ = sample;
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}
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}
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void SampleCounter::Add(const SampleCounter& other) {
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if (sum_ > 0) {
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RTC_DCHECK_LE(other.sum_, std::numeric_limits<int64_t>::max() - sum_);
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} else {
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RTC_DCHECK_GE(other.sum_, std::numeric_limits<int64_t>::min() - sum_);
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}
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sum_ += other.sum_;
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RTC_DCHECK_LE(other.num_samples_,
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std::numeric_limits<int64_t>::max() - num_samples_);
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num_samples_ += other.num_samples_;
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if (other.max_ && (!max_ || *max_ < *other.max_))
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max_ = other.max_;
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}
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absl::optional<int> SampleCounter::Avg(int64_t min_required_samples) const {
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RTC_DCHECK_GT(min_required_samples, 0);
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if (num_samples_ < min_required_samples)
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return absl::nullopt;
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return rtc::dchecked_cast<int>(sum_ / num_samples_);
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}
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absl::optional<int> SampleCounter::Max() const {
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return max_;
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}
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void SampleCounter::Reset() {
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*this = {};
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}
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SampleCounterWithVariance::SampleCounterWithVariance() = default;
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SampleCounterWithVariance::~SampleCounterWithVariance() = default;
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absl::optional<int64_t> SampleCounterWithVariance::Variance(
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int64_t min_required_samples) const {
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RTC_DCHECK_GT(min_required_samples, 0);
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if (num_samples_ < min_required_samples)
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return absl::nullopt;
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// E[(x-mean)^2] = E[x^2] - mean^2
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int64_t mean = sum_ / num_samples_;
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return sum_squared_ / num_samples_ - mean * mean;
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}
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void SampleCounterWithVariance::Add(int sample) {
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SampleCounter::Add(sample);
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// Prevent overflow in squaring.
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RTC_DCHECK_GT(sample, std::numeric_limits<int32_t>::min());
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RTC_DCHECK_LE(int64_t{sample} * sample,
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std::numeric_limits<int64_t>::max() - sum_squared_);
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sum_squared_ += int64_t{sample} * sample;
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}
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void SampleCounterWithVariance::Add(const SampleCounterWithVariance& other) {
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SampleCounter::Add(other);
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RTC_DCHECK_LE(other.sum_squared_,
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std::numeric_limits<int64_t>::max() - sum_squared_);
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sum_squared_ += other.sum_squared_;
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}
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void SampleCounterWithVariance::Reset() {
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*this = {};
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}
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} // namespace rtc
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