ClickHouse/dbms/AggregateFunctions/AggregateFunctionIf.h
Ivan 97f2a2213e
Move all folders inside /dbms one level up (#9974)
* Move some code outside dbms/src folder
* Fix paths
2020-04-02 02:51:21 +03:00

115 lines
3.2 KiB
C++

#pragma once
#include <DataTypes/DataTypesNumber.h>
#include <Columns/ColumnsNumber.h>
#include <Common/assert_cast.h>
#include <AggregateFunctions/IAggregateFunction.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
/** Not an aggregate function, but an adapter of aggregate functions,
* which any aggregate function `agg(x)` makes an aggregate function of the form `aggIf(x, cond)`.
* The adapted aggregate function takes two arguments - a value and a condition,
* and calculates the nested aggregate function for the values when the condition is satisfied.
* For example, avgIf(x, cond) calculates the average x if `cond`.
*/
class AggregateFunctionIf final : public IAggregateFunctionHelper<AggregateFunctionIf>
{
private:
AggregateFunctionPtr nested_func;
size_t num_arguments;
public:
AggregateFunctionIf(AggregateFunctionPtr nested, const DataTypes & types)
: IAggregateFunctionHelper<AggregateFunctionIf>(types, nested->getParameters())
, nested_func(nested), num_arguments(types.size())
{
if (num_arguments == 0)
throw Exception("Aggregate function " + getName() + " require at least one argument", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
if (!isUInt8(types.back()))
throw Exception("Last argument for aggregate function " + getName() + " must be UInt8", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
String getName() const override
{
return nested_func->getName() + "If";
}
DataTypePtr getReturnType() const override
{
return nested_func->getReturnType();
}
void create(AggregateDataPtr place) const override
{
nested_func->create(place);
}
void destroy(AggregateDataPtr place) const noexcept override
{
nested_func->destroy(place);
}
bool hasTrivialDestructor() const override
{
return nested_func->hasTrivialDestructor();
}
size_t sizeOfData() const override
{
return nested_func->sizeOfData();
}
size_t alignOfData() const override
{
return nested_func->alignOfData();
}
void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena * arena) const override
{
if (assert_cast<const ColumnUInt8 &>(*columns[num_arguments - 1]).getData()[row_num])
nested_func->add(place, columns, row_num, arena);
}
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena * arena) const override
{
nested_func->merge(place, rhs, arena);
}
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
{
nested_func->serialize(place, buf);
}
void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena * arena) const override
{
nested_func->deserialize(place, buf, arena);
}
void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
{
nested_func->insertResultInto(place, to);
}
bool allocatesMemoryInArena() const override
{
return nested_func->allocatesMemoryInArena();
}
bool isState() const override
{
return nested_func->isState();
}
};
}