TimeUtil.hh

#ifndef __RAT_TimeUtil__
#define __RAT_TimeUtil__
 
#include <TTimeStamp.h>
 
namespace RAT {
// I am going to type the wrong number of zeros if I don't do this
// and I want an integer, not a double
const long TIME_UTIL_BILLION = 1000000000L;
 
// Return a new TTimeStamp offset by nanoseconds.  nanoseconds can be negative
inline TTimeStamp AddNanoseconds(const TTimeStamp &a, const long nanoseconds) {
  time_t new_sec = a.GetSec();
  long new_nsec = a.GetNanoSec() + nanoseconds;
  // Normalize
  if (new_nsec < 0) {
    new_sec -= 1 + (-new_nsec / TIME_UTIL_BILLION);
    new_nsec = TIME_UTIL_BILLION - (-new_nsec % TIME_UTIL_BILLION);
  } else if (new_nsec >= TIME_UTIL_BILLION) {
    new_sec += new_nsec / TIME_UTIL_BILLION;
    new_nsec = new_nsec % TIME_UTIL_BILLION;
  }
  return TTimeStamp(new_sec, new_nsec);
}
 
// Get time difference (a - b) in nanoseconds.  Note that maximum deltaT is
// +/-2^63 = 292 years
inline long TimeDifference(const TTimeStamp &a, const TTimeStamp &b) {
  return (a.GetSec() - b.GetSec()) * TIME_UTIL_BILLION + (a.GetNanoSec() - b.GetNanoSec());
}
}  // namespace RAT
 
#endif