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#pragma once
#include <DataTypes/DataTypeNullable.h>
#include <DataTypes/DataTypeNothing.h>
#include <Columns/IColumn.h>
#include <AggregateFunctions/IAggregateFunction.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteHelpers.h>
#include "DataTypes/IDataType.h"
namespace DB
{
struct Settings;
namespace ErrorCodes
{
extern const int INCORRECT_DATA;
}
/** Aggregate function that takes arbitrary number of arbitrary arguments and does nothing.
*/
class AggregateFunctionNothing final : public IAggregateFunctionHelper<AggregateFunctionNothing>
{
public:
AggregateFunctionNothing(const DataTypes & arguments, const Array & params, const DataTypePtr & result_type_)
: IAggregateFunctionHelper<AggregateFunctionNothing>(arguments, params, result_type_) {}
String getName() const override
{
return "nothing";
}
bool allocatesMemoryInArena() const override { return false; }
void create(AggregateDataPtr __restrict) const override
{
}
void destroy(AggregateDataPtr __restrict) const noexcept override
{
}
bool hasTrivialDestructor() const override
{
return true;
}
size_t sizeOfData() const override
{
return 0;
}
size_t alignOfData() const override
{
return 1;
}
void add(AggregateDataPtr __restrict, const IColumn **, size_t, Arena *) const override
{
}
void merge(AggregateDataPtr __restrict, ConstAggregateDataPtr, Arena *) const override
{
}
void serialize(ConstAggregateDataPtr __restrict, WriteBuffer & buf, std::optional<size_t>) const override
{
writeChar('\0', buf);
}
void deserialize(AggregateDataPtr __restrict, ReadBuffer & buf, std::optional<size_t>, Arena *) const override
{
[[maybe_unused]] char symbol;
readChar(symbol, buf);
if (symbol != '\0')
throw Exception(ErrorCodes::INCORRECT_DATA, "Incorrect state of aggregate function 'nothing', it should contain exactly one zero byte, while it is {}.", static_cast<UInt32>(symbol));
}
void insertResultInto(AggregateDataPtr __restrict, IColumn & to, Arena *) const override
{
to.insertDefault();
}
};
}
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