Stopwatch.cc

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#include <sys/times.h>
#include <unistd.h>
#include "Stopwatch.h"

using namespace utl;


const long Stopwatch::fgClockTicks = sysconf(_SC_CLK_TCK);


Stopwatch::Stopwatch() :
  fIsStopped(false),
  fUserTimeSum(0),
  fSystemTimeSum(0)
{
  times(&fStart);
}


void
Stopwatch::Reset()
{
  fIsStopped = true;
  fUserTimeSum = fSystemTimeSum = 0;
}


void
Stopwatch::Start()
{
  if (fIsStopped) {
    times(&fStart);
    fIsStopped = false;
  }
}


void
Stopwatch::Stop()
{
  if (!fIsStopped) {
    struct tms stop;
    times(&stop);
    fUserTimeSum += stop.tms_utime - fStart.tms_utime;
    fSystemTimeSum += stop.tms_stime - fStart.tms_stime;
    fIsStopped = true;
  }
}


double
Stopwatch::GetCPUTime(const CPUTime kind)
{
  if (fIsStopped)
    switch (kind) {
    case eTotal:
      return double(fUserTimeSum + fSystemTimeSum)/fgClockTicks*second;
    case eUser:
      return double(fUserTimeSum)/fgClockTicks*second;
    case eSystem:
      return double(fSystemTimeSum)/fgClockTicks*second;
    }
  else {
    struct tms stop;
    times(&stop);
    switch (kind) {
    case eTotal:
      return double(fUserTimeSum + fSystemTimeSum +
                    stop.tms_utime - fStart.tms_utime +
                    stop.tms_stime - fStart.tms_stime)/fgClockTicks*second;
    case eUser:
      return double(fUserTimeSum +
                    stop.tms_utime - fStart.tms_utime)/fgClockTicks*second;
    case eSystem:
      return double(fSystemTimeSum +
                    stop.tms_stime - fStart.tms_stime)/fgClockTicks*second;
    }
  }

  return 0;
}


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