ClickHouse/dbms/include/DB/AggregateFunctions/AggregateFunctionSum.h
2016-05-28 10:48:40 +03:00

71 lines
1.7 KiB
C++

#pragma once
#include <DB/IO/WriteHelpers.h>
#include <DB/IO/ReadHelpers.h>
#include <DB/DataTypes/DataTypesNumberFixed.h>
#include <DB/AggregateFunctions/IUnaryAggregateFunction.h>
namespace DB
{
template <typename T>
struct AggregateFunctionSumData
{
T sum;
AggregateFunctionSumData() : sum(0) {}
};
/// Считает сумму чисел.
template <typename T>
class AggregateFunctionSum final : public IUnaryAggregateFunction<AggregateFunctionSumData<typename NearestFieldType<T>::Type>, AggregateFunctionSum<T> >
{
public:
String getName() const override { return "sum"; }
DataTypePtr getReturnType() const override
{
return std::make_shared<typename DataTypeFromFieldType<typename NearestFieldType<T>::Type>::Type>();
}
void setArgument(const DataTypePtr & argument)
{
if (!argument->behavesAsNumber())
throw Exception("Illegal type " + argument->getName() + " of argument for aggregate function " + getName(),
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
void addImpl(AggregateDataPtr place, const IColumn & column, size_t row_num) const
{
this->data(place).sum += static_cast<const ColumnVector<T> &>(column).getData()[row_num];
}
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs) const override
{
this->data(place).sum += this->data(rhs).sum;
}
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
{
writeBinary(this->data(place).sum, buf);
}
void deserialize(AggregateDataPtr place, ReadBuffer & buf) const override
{
readBinary(this->data(place).sum, buf);
}
void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
{
static_cast<ColumnVector<typename NearestFieldType<T>::Type> &>(to).getData().push_back(this->data(place).sum);
}
};
}