base/include/android-base/chrono_utils.h

/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <chrono>
#include <sstream>

#if __cplusplus > 201103L && !defined(__WIN32)  // C++14
using namespace std::chrono_literals;
#endif

namespace android {
namespace base {

// A std::chrono clock based on CLOCK_BOOTTIME.
class boot_clock {
 public:
  typedef std::chrono::nanoseconds duration;
  typedef std::chrono::time_point<boot_clock, duration> time_point;

  static time_point now();
};

class Timer {
 public:
  Timer() : start_(boot_clock::now()) {}

  std::chrono::milliseconds duration() const {
    return std::chrono::duration_cast<std::chrono::milliseconds>(boot_clock::now() - start_);
  }

 private:
  boot_clock::time_point start_;
};

std::ostream& operator<<(std::ostream& os, const Timer& t);

}  // namespace base
}  // namespace android