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 | class FunctionToLowCardinality: public IFunction |
14 | { |
15 | public: |
16 | static constexpr auto name = "toLowCardinality"; |
17 | static FunctionPtr create(const Context &) { return std::make_shared<FunctionToLowCardinality>(); } |
18 | |
19 | String getName() const override { return name; } |
20 | |
21 | size_t getNumberOfArguments() const override { return 1; } |
22 | |
23 | bool useDefaultImplementationForNulls() const override { return false; } |
24 | bool useDefaultImplementationForConstants() const override { return true; } |
25 | bool useDefaultImplementationForLowCardinalityColumns() const override { return false; } |
26 | |
27 | DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override |
28 | { |
29 | if (arguments[0]->lowCardinality()) |
30 | return arguments[0]; |
31 | |
32 | return std::make_shared<DataTypeLowCardinality>(arguments[0]); |
33 | } |
34 | |
35 | void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override |
36 | { |
37 | auto arg_num = arguments[0]; |
38 | const auto & arg = block.getByPosition(arg_num); |
39 | auto & res = block.getByPosition(result); |
40 | |
41 | if (arg.type->lowCardinality()) |
42 | res.column = arg.column; |
43 | else |
44 | { |
45 | auto column = res.type->createColumn(); |
46 | typeid_cast<ColumnLowCardinality &>(*column).insertRangeFromFullColumn(*arg.column, 0, arg.column->size()); |
47 | res.column = std::move(column); |
48 | } |
49 | } |
50 | }; |
51 | |
52 | |
53 | void registerFunctionToLowCardinality(FunctionFactory & factory) |
54 | { |
55 | factory.registerFunction<FunctionToLowCardinality>(); |
56 | } |
57 | |
58 | } |
59 |