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95 lines
3.2 KiB
C++
95 lines
3.2 KiB
C++
#pragma once
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#include <common/StringRef.h>
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#include <DataTypes/IDataType.h>
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#include <AggregateFunctions/IAggregateFunction.h>
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#include <AggregateFunctions/AggregateFunctionMinMaxAny.h> // SingleValueDataString used in embedded compiler
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int ILLEGAL_TYPE_OF_ARGUMENT;
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}
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/// For possible values for template parameters, see AggregateFunctionMinMaxAny.h
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template <typename ResultData, typename ValueData>
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struct AggregateFunctionArgMinMaxData
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{
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using ResultData_t = ResultData;
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using ValueData_t = ValueData;
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ResultData result; // the argument at which the minimum/maximum value is reached.
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ValueData value; // value for which the minimum/maximum is calculated.
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static bool allocatesMemoryInArena()
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{
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return ResultData::allocatesMemoryInArena() || ValueData::allocatesMemoryInArena();
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}
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};
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/// Returns the first arg value found for the minimum/maximum value. Example: argMax(arg, value).
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template <typename Data>
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class AggregateFunctionArgMinMax final : public IAggregateFunctionDataHelper<Data, AggregateFunctionArgMinMax<Data>>
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{
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private:
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const DataTypePtr & type_res;
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const DataTypePtr & type_val;
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public:
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AggregateFunctionArgMinMax(const DataTypePtr & type_res_, const DataTypePtr & type_val_)
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: IAggregateFunctionDataHelper<Data, AggregateFunctionArgMinMax<Data>>({type_res_, type_val_}, {}),
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type_res(this->argument_types[0]), type_val(this->argument_types[1])
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{
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if (!type_val->isComparable())
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throw Exception("Illegal type " + type_val->getName() + " of second argument of aggregate function " + getName()
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+ " because the values of that data type are not comparable", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
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}
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String getName() const override { return StringRef(Data::ValueData_t::name()) == StringRef("min") ? "argMin" : "argMax"; }
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DataTypePtr getReturnType() const override
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{
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return type_res;
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}
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void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena * arena) const override
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{
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if (this->data(place).value.changeIfBetter(*columns[1], row_num, arena))
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this->data(place).result.change(*columns[0], row_num, arena);
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}
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void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena * arena) const override
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{
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if (this->data(place).value.changeIfBetter(this->data(rhs).value, arena))
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this->data(place).result.change(this->data(rhs).result, arena);
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}
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void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
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{
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this->data(place).result.write(buf, *type_res);
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this->data(place).value.write(buf, *type_val);
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}
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void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena * arena) const override
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{
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this->data(place).result.read(buf, *type_res, arena);
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this->data(place).value.read(buf, *type_val, arena);
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}
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bool allocatesMemoryInArena() const override
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{
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return Data::allocatesMemoryInArena();
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}
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void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
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{
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this->data(place).result.insertResultInto(to);
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}
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};
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}
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