beedb/include/execution/aggregator.h

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2022-04-04 20:25:01 +02:00
/*------------------------------------------------------------------------------*
* Architecture & Implementation of DBMS *
*------------------------------------------------------------------------------*
* Copyright 2022 Databases and Information Systems Group TU Dortmund *
* Visit us at *
* http://dbis.cs.tu-dortmund.de/cms/en/home/ *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR *
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, *
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *
* OTHER DEALINGS IN THE SOFTWARE. *
* *
* Authors: *
* Maximilian Berens <maximilian.berens@tu-dortmund.de> *
* Roland Kühn <roland.kuehn@cs.tu-dortmund.de> *
* Jan Mühlig <jan.muehlig@tu-dortmund.de> *
*------------------------------------------------------------------------------*
*/
#pragma once
#include <cstdint>
#include <table/tuple.h>
#include <table/value.h>
namespace beedb::execution
{
class AggregatorInterface
{
public:
explicit AggregatorInterface(const std::uint16_t schema_index) : _schema_index(schema_index)
{
}
virtual ~AggregatorInterface() = default;
virtual void aggregate(const table::Tuple &tuple) = 0;
virtual table::Value value() = 0;
virtual void reset() = 0;
protected:
[[nodiscard]] std::uint16_t schema_index() const
{
return _schema_index;
}
private:
const std::uint16_t _schema_index;
};
class CountAggregator : public AggregatorInterface
{
public:
explicit CountAggregator(const std::uint16_t schema_index) : AggregatorInterface(schema_index)
{
}
~CountAggregator() override = default;
void aggregate(const table::Tuple &) override
{
++_count;
}
table::Value value() override
{
return table::Value(table::Type{table::Type::LONG}, {static_cast<std::int64_t>(_count)});
}
void reset() override
{
_count = 0u;
}
private:
std::uint64_t _count = 0u;
};
class SumAggregator : public AggregatorInterface
{
public:
SumAggregator(const std::uint16_t schema_index, const table::Type::Id type)
: AggregatorInterface(schema_index), _type(type), _sum(table::Value::make_zero(_type))
{
}
~SumAggregator() override = default;
void aggregate(const table::Tuple &tuple) override
{
_sum += tuple.get(AggregatorInterface::schema_index());
}
table::Value value() override
{
return _sum;
}
void reset() override
{
_sum = table::Value::make_zero(_type);
}
private:
const table::Type::Id _type;
table::Value _sum;
};
class AverageAggregator : public AggregatorInterface
{
public:
AverageAggregator(const std::uint16_t schema_index, const table::Type::Id type)
: AggregatorInterface(schema_index), _type(type), _sum(table::Value::make_zero(_type))
{
}
~AverageAggregator() override = default;
void aggregate(const table::Tuple &tuple) override
{
_sum += tuple.get(AggregatorInterface::schema_index());
_count++;
}
table::Value value() override
{
if (_type == table::Type::Id::LONG)
{
return table::Value(table::Type{table::Type::Id::DECIMAL},
_sum.get<std::int64_t>() / static_cast<double>(_count));
}
else if (_type == table::Type::Id::INT)
{
return table::Value(table::Type{table::Type::Id::DECIMAL},
_sum.get<std::int32_t>() / static_cast<double>(_count));
}
else if (_type == table::Type::Id::DECIMAL)
{
return table::Value(table::Type{table::Type::Id::DECIMAL},
_sum.get<double>() / static_cast<double>(_count));
}
return table::Value::make_zero(_type);
}
void reset() override
{
_sum = table::Value::make_zero(_type);
_count = 0u;
}
private:
const table::Type::Id _type;
table::Value _sum;
std::uint64_t _count = 0u;
};
class MinAggregator : public AggregatorInterface
{
public:
MinAggregator(const std::uint16_t schema_index, const table::Type::Id type)
: AggregatorInterface(schema_index), _type(type), _min(table::Value::make_null(_type))
{
}
~MinAggregator() override = default;
void aggregate(const table::Tuple &tuple) override
{
const auto value = tuple.get(AggregatorInterface::schema_index());
if ((value == nullptr) == false && (_min == nullptr || value < _min))
{
_min = value;
}
}
table::Value value() override
{
return _min;
}
void reset() override
{
_min = table::Value::make_null(_type);
}
private:
const table::Type::Id _type;
table::Value _min;
};
class MaxAggregator : public AggregatorInterface
{
public:
MaxAggregator(const std::uint16_t schema_index, const table::Type::Id type)
: AggregatorInterface(schema_index), _type(type), _max(table::Value::make_null(_type))
{
}
~MaxAggregator() override = default;
void aggregate(const table::Tuple &tuple) override
{
const auto value = tuple.get(AggregatorInterface::schema_index());
if ((value == nullptr) == false && (_max == nullptr || value > _max))
{
_max = value;
}
}
table::Value value() override
{
return _max;
}
void reset() override
{
_max = table::Value::make_null(_type);
}
private:
const table::Type::Id _type;
table::Value _max;
};
} // namespace beedb::execution