|  | /* | 
|  | *  Copyright 2018 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 "rtc_base/experiments/normalize_simulcast_size_experiment.h" | 
|  |  | 
|  | #include <stdio.h> | 
|  |  | 
|  | #include <string> | 
|  |  | 
|  | #include "api/field_trials_view.h" | 
|  | #include "rtc_base/logging.h" | 
|  |  | 
|  | namespace webrtc { | 
|  | namespace { | 
|  | constexpr char kFieldTrial[] = "WebRTC-NormalizeSimulcastResolution"; | 
|  | constexpr int kMinSetting = 0; | 
|  | constexpr int kMaxSetting = 5; | 
|  | }  // namespace | 
|  |  | 
|  | std::optional<int> NormalizeSimulcastSizeExperiment::GetBase2Exponent( | 
|  | const FieldTrialsView& field_trials) { | 
|  | if (!field_trials.IsEnabled(kFieldTrial)) | 
|  | return std::nullopt; | 
|  |  | 
|  | const std::string group = field_trials.Lookup(kFieldTrial); | 
|  | if (group.empty()) | 
|  | return std::nullopt; | 
|  |  | 
|  | int exponent; | 
|  | if (sscanf(group.c_str(), "Enabled-%d", &exponent) != 1) { | 
|  | RTC_LOG(LS_WARNING) << "No parameter provided."; | 
|  | return std::nullopt; | 
|  | } | 
|  |  | 
|  | if (exponent < kMinSetting || exponent > kMaxSetting) { | 
|  | RTC_LOG(LS_WARNING) << "Unsupported exp value provided, value ignored."; | 
|  | return std::nullopt; | 
|  | } | 
|  |  | 
|  | return std::optional<int>(exponent); | 
|  | } | 
|  |  | 
|  | }  // namespace webrtc |