arrow/util/stopwatch.h

0001 // Licensed to the Apache Software Foundation (ASF) under one
0002 // or more contributor license agreements.  See the NOTICE file
0003 // distributed with this work for additional information
0004 // regarding copyright ownership.  The ASF licenses this file
0005 // to you under the Apache License, Version 2.0 (the
0006 // "License"); you may not use this file except in compliance
0007 // with the License.  You may obtain a copy of the License at
0008 //
0009 //   http://www.apache.org/licenses/LICENSE-2.0
0010 //
0011 // Unless required by applicable law or agreed to in writing,
0012 // software distributed under the License is distributed on an
0013 // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
0014 // KIND, either express or implied.  See the License for the
0015 // specific language governing permissions and limitations
0016 // under the License.
0017
0018 #pragma once
0019
0020 #include <cassert>
0021 #include <chrono>
0022
0023 namespace arrow {
0024 namespace internal {
0025
0026 class StopWatch {
0027   // This clock should give us wall clock time
0028   using ClockType = std::chrono::steady_clock;
0029
0030  public:
0031   StopWatch() {}
0032
0033   void Start() { start_ = ClockType::now(); }
0034
0035   // Returns time in nanoseconds.
0036   uint64_t Stop() {
0037     auto stop = ClockType::now();
0038     std::chrono::nanoseconds d = stop - start_;
0039     assert(d.count() >= 0);
0040     return static_cast<uint64_t>(d.count());
0041   }
0042
0043  private:
0044   std::chrono::time_point<ClockType> start_;
0045 };
0046
0047 }  // namespace internal
0048 }  // namespace arrow