Function ToDouble

cpp/src/gandiva/precompiled/decimal_ops.cc:517–526

}

double ToDouble(const BasicDecimalScalar128& in, bool* overflow) {
  // convert int128 to double
  int64_t sign = in.value().Sign();
  auto value_abs = BasicDecimal128::Abs(in.value());
  double unscaled = static_cast<double>(value_abs.low_bits()) +
                    std::ldexp(static_cast<double>(value_abs.high_bits()), 64);

  // scale double.
  return (unscaled * sign) / kDoubleScaleMultipliers[in.scale()];
}

BasicDecimal128 FromInt64(int64_t in, int32_t precision, int32_t scale, bool* overflow) {
  // check if multiplying by scale will cause an overflow.