Stopwatch.hpp

// Copyright Ingo Proff 2017.
// https://github.com/CrikeeIP/Stopwatch
// Distributed under the MIT Software License (X11 license).
// (See accompanying file LICENSE)

#pragma once

#include <vector>
#include <chrono>


namespace stopwatch{

class Stopwatch{
public:
   enum TimeFormat{ NANOSECONDS, MICROSECONDS, MILLISECONDS, SECONDS };

   Stopwatch(): start_time(), laps({}) {
      start();
   }

   void start(){
      start_time = std::chrono::high_resolution_clock::now();
      laps = {start_time};
   }

   template<TimeFormat fmt = TimeFormat::MILLISECONDS>
   std::uint64_t lap(){
      const auto t = std::chrono::high_resolution_clock::now();
      const auto last_r = laps.back();
      laps.push_back( t );
      return ticks<fmt>(last_r, t);
   }

   template<TimeFormat fmt = TimeFormat::MILLISECONDS>
   std::uint64_t elapsed(){
      const auto end_time = std::chrono::high_resolution_clock::now();
      return ticks<fmt>(start_time, end_time);
   }

   template<TimeFormat fmt_total = TimeFormat::MILLISECONDS, TimeFormat fmt_lap = fmt_total>
   std::pair<std::uint64_t, std::vector<std::uint64_t>> elapsed_laps(){
      std::vector<std::uint64_t> lap_times;
      lap_times.reserve(laps.size()-1);

      for( std::size_t idx = 0; idx <= laps.size()-2; idx++){
         const auto lap_end = laps[idx+1];
         const auto lap_start = laps[idx];
         lap_times.push_back( ticks<fmt_lap>(lap_start, lap_end) );
      }

      return { ticks<fmt_total>(start_time, laps.back()), lap_times };
   }

private:
   typedef std::chrono::time_point<std::chrono::high_resolution_clock> time_pt;
   time_pt start_time;
   std::vector<time_pt> laps;

   template<TimeFormat fmt = TimeFormat::MILLISECONDS>
   static std::uint64_t ticks( const time_pt& start_time, const time_pt& end_time){
      const auto duration = end_time - start_time;
      const std::uint64_t ns_count = std::chrono::duration_cast<std::chrono::nanoseconds>(duration).count();

      switch(fmt){
      case TimeFormat::NANOSECONDS:
      {
         return ns_count;
      }
      case TimeFormat::MICROSECONDS:
      {
         std::uint64_t up = ((ns_count/100)%10 >= 5) ? 1 : 0;
         const auto mus_count = (ns_count /1000) + up;
         return mus_count;
      }
      case TimeFormat::MILLISECONDS:
      {
         std::uint64_t up = ((ns_count/100000)%10 >= 5) ? 1 : 0;
         const auto ms_count = (ns_count /1000000) + up;
         return ms_count;
      }
      case TimeFormat::SECONDS:
      {
         std::uint64_t up = ((ns_count/100000000)%10 >= 5) ? 1 : 0;
         const auto s_count = (ns_count /1000000000) + up;
         return s_count;
      }
      }
    }
};


constexpr Stopwatch::TimeFormat ns = Stopwatch::TimeFormat::NANOSECONDS;
constexpr Stopwatch::TimeFormat mus = Stopwatch::TimeFormat::MICROSECONDS;
constexpr Stopwatch::TimeFormat ms = Stopwatch::TimeFormat::MILLISECONDS;
constexpr Stopwatch::TimeFormat s = Stopwatch::TimeFormat::SECONDS;

constexpr Stopwatch::TimeFormat nanoseconds = Stopwatch::TimeFormat::NANOSECONDS;
constexpr Stopwatch::TimeFormat microseconds = Stopwatch::TimeFormat::MICROSECONDS;
constexpr Stopwatch::TimeFormat milliseconds = Stopwatch::TimeFormat::MILLISECONDS;
constexpr Stopwatch::TimeFormat seconds = Stopwatch::TimeFormat::SECONDS;


std::string show_times( const std::vector<std::uint64_t>& times ){
    std::string result("{");
    for( const auto& t : times ){
        result += std::to_string(t) + ",";
    }
    result.back() = static_cast<char>('}');
    return result;
}

} //namespace stopwatch