uint64
fgRandUint64()
{
    uint64  hi = rng.genInt(),
            lo = rng.genInt();
    return (lo + (hi << 32));
}
uint
fgRandUint(uint size)
{
    return uint(rng.genInt()) % size;
}
bool
randFlip()
{
    return (rng.genInt() > (numeric_limits<uint>::max()/2));
}