Function FormatDecimalValue

cpp/src/parquet/types.cc:119–159

}

std::string FormatDecimalValue(Type::type parquet_type, ::std::string_view val,
                               const std::shared_ptr<const LogicalType>& logical_type) {
  ARROW_DCHECK(logical_type != nullptr && logical_type->is_decimal());

  const auto& decimal_type =
      ::arrow::internal::checked_cast<const DecimalLogicalType&>(*logical_type);
  const int32_t scale = decimal_type.scale();

  std::stringstream result;
  switch (parquet_type) {
    case Type::INT32: {
      int32_t int_value{};
      std::memcpy(&int_value, val.data(), sizeof(int32_t));
      ::arrow::Decimal128 decimal_value(int_value);
      result << decimal_value.ToString(scale);
      break;
    }
    case Type::INT64: {
      int64_t long_value{};
      std::memcpy(&long_value, val.data(), sizeof(int64_t));
      ::arrow::Decimal128 decimal_value(long_value);
      result << decimal_value.ToString(scale);
      break;
    }
    case Type::FIXED_LEN_BYTE_ARRAY:
    case Type::BYTE_ARRAY: {
      auto decimal_result = ::arrow::Decimal256::FromBigEndian(
          reinterpret_cast<const uint8_t*>(val.data()), static_cast<int32_t>(val.size()));
      if (!decimal_result.ok()) {
        throw ParquetException("Failed to parse decimal value: ",
                               decimal_result.status().message());
      }
      result << decimal_result.ValueUnsafe().ToString(scale);
      break;
    }
    default:
      throw ParquetException("Unsupported decimal type: ", TypeToString(parquet_type));
  }

  return result.str();
}

std::string FormatNonUTF8Value(::std::string_view val) {
  if (val.empty()) {