ClickHouse/dbms/include/DB/Functions/Conditional/NumericEvaluator.h

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#pragma once
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#include <DB/Functions/Conditional/CondException.h>
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#include <DB/Functions/Conditional/common.h>
#include <DB/Functions/Conditional/CondSource.h>
#include <DB/Functions/NumberTraits.h>
#include <DB/DataTypes/DataTypesNumberFixed.h>
#include <DB/Columns/ColumnVector.h>
#include <DB/Columns/ColumnConst.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace Conditional
{
namespace
{
/// This class provides type-independent access to the values of a numeric branch
/// (then, else) column. Returned values have the type TResult.
template <typename TResult>
class NumericSource
{
public:
virtual TResult get(size_t i) const = 0;
virtual ~NumericSource() = default;
};
template <typename TResult>
using NumericSourcePtr = std::unique_ptr<NumericSource<TResult> >;
template <typename TResult>
using NumericSources = std::vector<NumericSourcePtr<TResult> >;
/// Column type-specific implementation of NumericSource.
template <typename TResult, typename TType, bool IsConst>
class NumericSourceImpl;
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template <typename TResult, typename TType>
class NumericSourceImpl<TResult, TType, true> final : public NumericSource<TResult>
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{
public:
NumericSourceImpl(const Block & block, const ColumnNumbers & args, const Branch & br)
{
size_t index = br.index;
const ColumnPtr & col = block.getByPosition(args[index]).column;
const auto * const_col = typeid_cast<const ColumnConst<TType> *>(&*col);
if (const_col == nullptr)
throw Exception{"Internal error", ErrorCodes::LOGICAL_ERROR};
data = const_col->getData();
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}
NumericSourceImpl(const NumericSourceImpl &) = delete;
NumericSourceImpl & operator=(const NumericSourceImpl &) = delete;
NumericSourceImpl(NumericSourceImpl &&) = default;
NumericSourceImpl & operator=(NumericSourceImpl &&) = default;
TResult get(size_t i) const override
{
return static_cast<TResult>(data);
};
private:
TType data;
};
template <typename TResult, typename TType>
class NumericSourceImpl<TResult, TType, false> final : public NumericSource<TResult>
{
public:
NumericSourceImpl(const Block & block, const ColumnNumbers & args, const Branch & br)
: data_array{initDataArray(block, args, br)}
{
}
NumericSourceImpl(const NumericSourceImpl &) = delete;
NumericSourceImpl & operator=(const NumericSourceImpl &) = delete;
NumericSourceImpl(NumericSourceImpl &&) = default;
NumericSourceImpl & operator=(NumericSourceImpl &&) = default;
TResult get(size_t i) const override
{
return static_cast<TResult>(data_array[i]);
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};
private:
static const PaddedPODArray<TType> & initDataArray(const Block & block,
const ColumnNumbers & args, const Branch & br)
{
size_t index = br.index;
const ColumnPtr & col = block.getByPosition(args[index]).column;
const auto * vec_col = typeid_cast<const ColumnVector<TType> *>(&*col);
if (vec_col == nullptr)
throw Exception{"Internal error", ErrorCodes::LOGICAL_ERROR};
return vec_col->getData();
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}
private:
const PaddedPODArray<TType> & data_array;
};
/// Create a numeric column accessor if TType is the type registered
/// in the specified branch info.
template <typename TResult, typename TType>
class NumericSourceCreator final
{
public:
static bool execute(NumericSourcePtr<TResult> & source, const Block & block,
const ColumnNumbers & args, const Branch & br)
{
auto type_name = br.type->getName();
if (TypeName<TType>::get() == type_name)
{
if (br.is_const)
source = std::make_unique<NumericSourceImpl<TResult, TType, true> >(block, args, br);
else
source = std::make_unique<NumericSourceImpl<TResult, TType, false> >(block, args, br);
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return true;
}
else
return false;
}
};
}
/// Processing of multiIf in the case of scalar numeric types.
template <typename TResult>
class NumericEvaluator final
{
public:
static void perform(const Branches & branches, Block & block, const ColumnNumbers & args, size_t result, size_t tracker)
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{
const CondSources conds = createConds(block, args);
const NumericSources<TResult> sources = createNumericSources(block, args, branches);
size_t row_count = conds[0].getSize();
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PaddedPODArray<TResult> & res = createSink(block, result, row_count);
ColumnUInt64 * tracker_col = nullptr;
if (tracker != result)
{
auto & col = block.unsafeGetByPosition(tracker).column;
col = std::make_shared<ColumnUInt64>(row_count);
tracker_col = static_cast<ColumnUInt64 *>(col.get());
}
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for (size_t cur_row = 0; cur_row < row_count; ++cur_row)
{
bool has_triggered_cond = false;
size_t cur_source = 0;
for (const auto & cond : conds)
{
if (cond.get(cur_row))
{
res[cur_row] = sources[cur_source]->get(cur_row);
if (tracker_col != nullptr)
{
auto & data = tracker_col->getData();
data[cur_row] = args[branches[cur_source].index];
}
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has_triggered_cond = true;
break;
}
++cur_source;
}
if (!has_triggered_cond)
{
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res[cur_row] = sources.back()->get(cur_row);
if (tracker_col != nullptr)
{
auto & data = tracker_col->getData();
data[cur_row] = args[branches.back().index];
}
}
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}
}
private:
/// Create the result column.
static PaddedPODArray<TResult> & createSink(Block & block, size_t result, size_t size)
{
std::shared_ptr<ColumnVector<TResult>> col_res = std::make_shared<ColumnVector<TResult>>();
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block.getByPosition(result).column = col_res;
typename ColumnVector<TResult>::Container_t & vec_res = col_res->getData();
vec_res.resize(size);
return vec_res;
}
/// Create accessors for condition values.
static CondSources createConds(const Block & block, const ColumnNumbers & args)
{
CondSources conds;
conds.reserve(getCondCount(args));
for (size_t i = firstCond(); i < elseArg(args); i = nextCond(i))
conds.emplace_back(block, args, i);
return conds;
}
/// Create accessors for branch values.
static NumericSources<TResult> createNumericSources(const Block & block,
const ColumnNumbers & args, const Branches & branches)
{
NumericSources<TResult> sources;
sources.reserve(branches.size());
for (const auto & br : branches)
{
NumericSourcePtr<TResult> source;
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if (! (NumericSourceCreator<TResult, UInt8>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, UInt16>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, UInt32>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, UInt64>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, Int8>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, Int16>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, Int32>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, Int64>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, Float32>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, Float64>::execute(source, block, args, br)
|| NumericSourceCreator<TResult, Null>::execute(source, block, args, br)))
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throw CondException{CondErrorCodes::NUMERIC_EVALUATOR_ILLEGAL_ARGUMENT, toString(br.index)};
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sources.push_back(std::move(source));
}
return sources;
}
};
/// Processing of multiIf in the case of an invalid return type.
template <>
class NumericEvaluator<NumberTraits::Error>
{
public:
static void perform(const Branches & branches, Block & block, const ColumnNumbers & args, size_t result, size_t tracker)
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{
throw Exception{"Internal logic error", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
}
};
}
}