1 | #include <Functions/IFunctionImpl.h> |
---|---|
2 | #include <Functions/FunctionFactory.h> |
3 | #include <DataTypes/DataTypesNumber.h> |
4 | #include <DataTypes/DataTypeLowCardinality.h> |
5 | #include <Columns/ColumnsNumber.h> |
6 | #include <Columns/ColumnLowCardinality.h> |
7 | #include <Common/typeid_cast.h> |
8 | |
9 | |
10 | namespace DB |
11 | { |
12 | |
13 | namespace ErrorCodes |
14 | { |
15 | extern const int ILLEGAL_TYPE_OF_ARGUMENT; |
16 | } |
17 | |
18 | class FunctionLowCardinalityIndices: public IFunction |
19 | { |
20 | public: |
21 | static constexpr auto name = "lowCardinalityIndices"; |
22 | static FunctionPtr create(const Context &) { return std::make_shared<FunctionLowCardinalityIndices>(); } |
23 | |
24 | String getName() const override { return name; } |
25 | |
26 | size_t getNumberOfArguments() const override { return 1; } |
27 | |
28 | bool useDefaultImplementationForNulls() const override { return false; } |
29 | bool useDefaultImplementationForConstants() const override { return true; } |
30 | bool useDefaultImplementationForLowCardinalityColumns() const override { return false; } |
31 | |
32 | DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override |
33 | { |
34 | auto * type = typeid_cast<const DataTypeLowCardinality *>(arguments[0].get()); |
35 | if (!type) |
36 | throw Exception("First first argument of function lowCardinalityIndexes must be ColumnLowCardinality, but got" |
37 | + arguments[0]->getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT); |
38 | |
39 | return std::make_shared<DataTypeUInt64>(); |
40 | } |
41 | |
42 | void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override |
43 | { |
44 | auto arg_num = arguments[0]; |
45 | const auto & arg = block.getByPosition(arg_num); |
46 | auto & res = block.getByPosition(result); |
47 | auto indexes_col = typeid_cast<const ColumnLowCardinality *>(arg.column.get())->getIndexesPtr(); |
48 | auto new_indexes_col = ColumnUInt64::create(indexes_col->size()); |
49 | auto & data = new_indexes_col->getData(); |
50 | for (size_t i = 0; i < data.size(); ++i) |
51 | data[i] = indexes_col->getUInt(i); |
52 | |
53 | res.column = std::move(new_indexes_col); |
54 | } |
55 | }; |
56 | |
57 | |
58 | void registerFunctionLowCardinalityIndices(FunctionFactory & factory) |
59 | { |
60 | factory.registerFunction<FunctionLowCardinalityIndices>(); |
61 | } |
62 | |
63 | } |
64 |