JToAImp.cc

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#include <chrono>
#include "JAcoustics/JToA.hh"

// FIXME: to be replaced by std::chrono::round once we move to C++17
namespace {
  template<class To, class Duration>
  To round(const Duration& d)
  {
    To   t0    = std::chrono::duration_cast<To>(d);
    To   t1    = t0 + To{1};
    auto diff0 = d - t0;
    auto diff1 = t1 - d;
    if (diff0 == diff1) {
      if (t0.count() & 1) {
        return t1;
      }
      return t0;
    } else if (diff0 < diff1) {
      return t0;
    }
    return t1;
  }
}

namespace JACOUSTICS {

  constexpr double  ONE_TICK_IN_NS            = 16E-9;  // one tick of the 62.5 MHz clock = 16 nanoseconds
  constexpr double  SECOND_IN_NANOSECOND      = 1E-9;
  constexpr double  SECOND_IN_MICROSECOND     = 1E-6;
  constexpr int64_t NANOSECONDS_IN_ONE_SECOND = 1000000000LL;
  constexpr int64_t NANOSECONDS_IN_ONE_TICK   = 16LL;

  JToA::JToA() = default;

  double JToA::daqFrameTimeStart_s() const
  {
    return (static_cast<double>(SECONDS) + static_cast<double>(TICKS) * ONE_TICK_IN_NS);
  }

  double JToA::TOA_S() const
  {
    return relativeToA_s() + daqFrameTimeStart_s();
  }

  int64_t JToA::relativeToA_ns() const
  {
    return TOA_NS - daqFrameTimeStart_ns();
  }

  double JToA::relativeToA_s() const
  {
    // to mimic what's done in the streamds retrieval, we truncate
    // to microseconds first, then go to seconds.
    std::chrono::microseconds mus = round<std::chrono::microseconds>(std::chrono::nanoseconds{relativeToA_ns()});
    return static_cast<double>(mus.count()) * SECOND_IN_MICROSECOND;
  }

  int64_t JToA::daqFrameTimeStart_ns() const
  {
    return SECONDS * NANOSECONDS_IN_ONE_SECOND + TICKS * NANOSECONDS_IN_ONE_TICK;
  }

}  // namespace JACOUSTICS