public void Update(long?val, long valMax)
{
AssertValid(valMax);
Contracts.Assert(!val.HasValue || -valMax <= val && val <= valMax);
if (!val.HasValue)
{
_cna++;
}
else if (val >= 0)
{
IntUtils.Add(ref _sumHi, ref _sumLo, (ulong)val);
}
else
{
IntUtils.Sub(ref _sumHi, ref _sumLo, (ulong)(-val));
}
AssertValid(valMax);
}