ClickHouse/src/Functions/array/emptyArray.cpp
2020-07-21 16:58:07 +03:00

94 lines
3.7 KiB
C++

#include <Functions/IFunctionImpl.h>
#include <Functions/FunctionFactory.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeDate.h>
#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypeDateTime64.h>
#include <DataTypes/DataTypeString.h>
#include <Columns/ColumnArray.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnsNumber.h>
namespace DB
{
/// TODO Make it simple.
template <typename Type> struct TypeToColumnType { using ColumnType = ColumnVector<Type>; };
template <> struct TypeToColumnType<String> { using ColumnType = ColumnString; };
template <typename DataType> struct DataTypeToName : TypeName<typename DataType::FieldType> { };
template <> struct DataTypeToName<DataTypeDate> { static std::string get() { return "Date"; } };
template <> struct DataTypeToName<DataTypeDateTime> { static std::string get() { return "DateTime"; } };
template <typename DataType>
struct FunctionEmptyArray : public IFunction
{
static constexpr auto base_name = "emptyArray";
static const String name;
static FunctionPtr create(const Context &) { return std::make_shared<FunctionEmptyArray>(); }
private:
String getName() const override
{
return name;
}
size_t getNumberOfArguments() const override { return 0; }
DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override
{
return std::make_shared<DataTypeArray>(std::make_shared<DataType>());
}
void executeImpl(Block & block, const ColumnNumbers &, size_t result, size_t input_rows_count) const override
{
using UnderlyingColumnType = typename TypeToColumnType<typename DataType::FieldType>::ColumnType;
block.getByPosition(result).column = ColumnArray::create(
UnderlyingColumnType::create(),
ColumnArray::ColumnOffsets::create(input_rows_count, 0));
}
};
template <typename DataType>
const String FunctionEmptyArray<DataType>::name = FunctionEmptyArray::base_name + String(DataTypeToName<DataType>::get());
using FunctionEmptyArrayUInt8 = FunctionEmptyArray<DataTypeUInt8>;
using FunctionEmptyArrayUInt16 = FunctionEmptyArray<DataTypeUInt16>;
using FunctionEmptyArrayUInt32 = FunctionEmptyArray<DataTypeUInt32>;
using FunctionEmptyArrayUInt64 = FunctionEmptyArray<DataTypeUInt64>;
using FunctionEmptyArrayInt8 = FunctionEmptyArray<DataTypeInt8>;
using FunctionEmptyArrayInt16 = FunctionEmptyArray<DataTypeInt16>;
using FunctionEmptyArrayInt32 = FunctionEmptyArray<DataTypeInt32>;
using FunctionEmptyArrayInt64 = FunctionEmptyArray<DataTypeInt64>;
using FunctionEmptyArrayFloat32 = FunctionEmptyArray<DataTypeFloat32>;
using FunctionEmptyArrayFloat64 = FunctionEmptyArray<DataTypeFloat64>;
using FunctionEmptyArrayDate = FunctionEmptyArray<DataTypeDate>;
using FunctionEmptyArrayDateTime = FunctionEmptyArray<DataTypeDateTime>;
using FunctionEmptyArrayString = FunctionEmptyArray<DataTypeString>;
void registerFunctionsEmptyArray(FunctionFactory & factory)
{
factory.registerFunction<FunctionEmptyArrayUInt8>();
factory.registerFunction<FunctionEmptyArrayUInt16>();
factory.registerFunction<FunctionEmptyArrayUInt32>();
factory.registerFunction<FunctionEmptyArrayUInt64>();
factory.registerFunction<FunctionEmptyArrayInt8>();
factory.registerFunction<FunctionEmptyArrayInt16>();
factory.registerFunction<FunctionEmptyArrayInt32>();
factory.registerFunction<FunctionEmptyArrayInt64>();
factory.registerFunction<FunctionEmptyArrayFloat32>();
factory.registerFunction<FunctionEmptyArrayFloat64>();
factory.registerFunction<FunctionEmptyArrayDate>();
factory.registerFunction<FunctionEmptyArrayDateTime>();
factory.registerFunction<FunctionEmptyArrayString>();
}
}