ClickHouse/dbms/src/Functions/materialize.cpp
2018-09-09 01:04:39 +03:00

52 lines
1.2 KiB
C++

#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
namespace DB
{
/** materialize(x) - materialize the constant
*/
class FunctionMaterialize : public IFunction
{
public:
static constexpr auto name = "materialize";
static FunctionPtr create(const Context &)
{
return std::make_shared<FunctionMaterialize>();
}
/// Get the function name.
String getName() const override
{
return name;
}
size_t getNumberOfArguments() const override
{
return 1;
}
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
return arguments[0];
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override
{
const auto & src = block.getByPosition(arguments[0]).column;
if (ColumnPtr converted = src->convertToFullColumnIfConst())
block.getByPosition(result).column = converted;
else
block.getByPosition(result).column = src;
}
};
void registerFunctionMaterialize(FunctionFactory & factory)
{
factory.registerFunction<FunctionMaterialize>();
}
}