Function createExact

src/DataTypes/DataTypeEnum.cpp:320–360

template <typename DataTypeEnum>
static DataTypePtr createExact(const ASTPtr & arguments, bool is_add = false, bool auto_assign = true, std::vector<UInt8> relative_flags = {})
{
    if (!arguments || arguments->children.empty())
        throw Exception(ErrorCodes::EMPTY_DATA_PASSED, "Enum data type cannot be empty");

    typename DataTypeEnum::Values values;
    values.reserve(arguments->children.size());

    using FieldType = typename DataTypeEnum::FieldType;

    if (auto_assign)
        relative_flags = autoAssignNumberForEnum(arguments, is_add);

    /// Children must be functions 'equals' with string literal as left argument and numeric literal as right argument.
    for (const ASTPtr & child : arguments->children)
    {
        const auto literals = getEnumElementLiterals(child);
        const String & field_name = literals.name_literal->value.safeGet<String>();

        /// safeGet<FieldType>() reinterprets the stored bits as Int64, so a UInt64 literal above
        /// Int64 max becomes negative (e.g. 18446744073709551615 -> -1) and would slip past the
        /// range check below. Reject such a value up front against the Enum's range.
        if (literals.value_literal->value.getType() == Field::Types::UInt64)
        {
            const UInt64 unsigned_value = literals.value_literal->value.safeGet<UInt64>();
            if (unsigned_value > static_cast<UInt64>(std::numeric_limits<FieldType>::max()))
                throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND, "Value {} for element '{}' exceeds range of {}",
                    toString(unsigned_value), field_name, EnumName<FieldType>::value);
        }

        const auto value = literals.value_literal->value.safeGet<FieldType>();

        if (value > std::numeric_limits<FieldType>::max() || value < std::numeric_limits<FieldType>::min())
            throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND, "Value {} for element '{}' exceeds range of {}",
                toString(value), field_name, EnumName<FieldType>::value);

        values.emplace_back(field_name, value);
    }

    return std::make_shared<DataTypeEnum>(values, is_add, std::move(relative_flags));
}

static DataTypePtr create(const ASTPtr & arguments, bool is_add = false)
{