text: /******************************************************************************
   * Copyright (C) 2016-2017, Cris Cecka.  All rights reserved.
   * Copyright (C) 2016-2017, NVIDIA CORPORATION.  All rights reserved.
   *
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   *       notice, this list of conditions and the following disclaimer.
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   *       notice, this list of conditions and the following disclaimer in the
   *       documentation and/or other materials provided with the distribution.
   *     * Neither the name of the NVIDIA CORPORATION nor the
   *       names of its contributors may be used to endorse or promote products
   *       derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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   ******************************************************************************/
  
  #pragma once
  
  #include <chrono>
  
  struct CPU_Clock {
    using clock      = std::chrono::high_resolution_clock;
    using time_point = clock::time_point;
    using duration   = clock::duration;
    using tick_type  = duration::rep;
  
    CPU_Clock() : starttime_(clock::now()) {}
    /** Start this clock */
    void start() {
      starttime_ = clock::now();
    }
    /** Get the duration this clock has been running */
    duration elapsed() const {
      return clock::now() - starttime_;
    }
    /** Get the number of seconds this clock has been running */
    double seconds() const {
      using units = std::chrono::duration<double>;
      return std::chrono::duration_cast<units>(elapsed()).count();
    }
   private:
    time_point starttime_;
  };
  