public BigIntegerBuilder(BigInteger bn) { _fWritable = false; _bits = bn.InternalBits; if (_bits != null) { _iuLast = _bits.Length - 1; _uSmall = _bits[0]; while (_iuLast > 0 && _bits[_iuLast] == 0) { _iuLast--; } } else { _iuLast = 0; _uSmall = NumericHelper.Abs(bn.InternalSign); } }