Function AddTime

general.cpp:802–881

// check for overflows, e.g. Dec 30 + 3 days = Jan 2 of next year.

void AddTime(CI *pci, int mode, int toadd)
{
  int d, h;
  real m;

  if (mode < 1 || mode == iAnimNow)
    mode = iAnimDay;

  h = (int)RFloor(pci->tim);
  m = RFract(pci->tim)*60.0;
  if (m < 60.0 && m + 1.0/rLarge >= 60.0)  // Avoid roundoff error.
    m = 60.0;
  if (mode == 13)
    m += 1.0/60000.0*(real)toadd;          // Add milliseconds.
  else if (mode == 12)
    m += 1.0/6000.0*(real)toadd;           // Add 1/100th seconds.
  else if (mode == 11)
    m += 1.0/600.0*(real)toadd;            // Add 1/10th seconds.
  else if (mode == 1)
    m += 1.0/60.0*(real)toadd;             // Add seconds.
  else if (mode == 2)
    m += (real)toadd;                      // Add minutes.

  // Add hours, either naturally or if minute value overflowed.

  if (m >= 60.0 || m < 0.0 || mode == 3) {
    if (m >= 60.0) {
      m -= 60.0; toadd = NSgn2(toadd);
    } else if (m < 0.0) {
      m += 60.0; toadd = -NSgn2(-toadd);
    }
    h += toadd;
  }

  // Add days, either naturally or if hour value overflowed.

  if (h >= 24 || h < 0 || mode == 4) {
    if (h >= 24) {
      h -= 24; toadd = NSgn2(toadd);
    } else if (h < 0) {
      h += 24; toadd = -NSgn2(-toadd);
    }
    pci->day = AddDay(pci->mon, pci->day, pci->yea, toadd);
  }

  // Add months, either naturally or if day value overflowed.

  d = DayInMonth(pci->mon, pci->yea);
  if (pci->day > d || pci->day < 1 || mode == 5) {
    if (pci->day > d) {
      pci->day -= d; toadd = NSgn2(toadd);
    } else if (pci->day < 1) {
      pci->day += DayInMonth(Mod12(pci->mon - 1), pci->yea);
      toadd = -NSgn2(-toadd);
    }
    pci->mon += toadd;
  }