ClickHouse/src/Functions/lowCardinalityIndices.cpp
Li Yin 4088c0a7f3 Automated function registration
Automated register all functions with below naming convention by
iterating through the symbols:
void DB::registerXXX(DB::FunctionFactory &)
2022-07-29 15:39:50 +08:00

66 lines
2.2 KiB
C++

#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeLowCardinality.h>
#include <Columns/ColumnsNumber.h>
#include <Columns/ColumnLowCardinality.h>
#include <Common/typeid_cast.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
class FunctionLowCardinalityIndices: public IFunction
{
public:
static constexpr auto name = "lowCardinalityIndices";
static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionLowCardinalityIndices>(); }
String getName() const override { return name; }
size_t getNumberOfArguments() const override { return 1; }
bool useDefaultImplementationForNulls() const override { return false; }
bool useDefaultImplementationForConstants() const override { return true; }
bool useDefaultImplementationForLowCardinalityColumns() const override { return false; }
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return false; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
const auto * type = typeid_cast<const DataTypeLowCardinality *>(arguments[0].get());
if (!type)
throw Exception("First first argument of function lowCardinalityIndexes must be ColumnLowCardinality, but got "
+ arguments[0]->getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeUInt64>();
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t /*input_rows_count*/) const override
{
const auto & arg = arguments[0];
auto indexes_col = typeid_cast<const ColumnLowCardinality *>(arg.column.get())->getIndexesPtr();
auto new_indexes_col = ColumnUInt64::create(indexes_col->size());
auto & data = new_indexes_col->getData();
for (size_t i = 0; i < data.size(); ++i)
data[i] = indexes_col->getUInt(i);
return new_indexes_col;
}
};
}
REGISTER_FUNCTION(LowCardinalityIndices)
{
factory.registerFunction<FunctionLowCardinalityIndices>();
}
}