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69 lines
1.4 KiB
C++
69 lines
1.4 KiB
C++
#include <Functions/IFunction.h>
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#include <Functions/FunctionFactory.h>
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#include <DataTypes/DataTypesNumber.h>
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#include <Columns/ColumnsNumber.h>
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#include <atomic>
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namespace DB
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{
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namespace
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{
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/** Incremental columns number among calls of this function. */
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class FunctionBlockNumber : public IFunction
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{
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private:
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mutable std::atomic<size_t> columns_number{0};
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public:
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static constexpr auto name = "blockNumber";
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static FunctionPtr create(ContextPtr)
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{
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return std::make_shared<FunctionBlockNumber>();
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}
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/// Get the function name.
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String getName() const override
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{
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return name;
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}
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bool isStateful() const override
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{
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return true;
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}
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size_t getNumberOfArguments() const override
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{
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return 0;
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}
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bool isDeterministic() const override { return false; }
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bool isDeterministicInScopeOfQuery() const override
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{
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return false;
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}
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DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override
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{
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return std::make_shared<DataTypeUInt64>();
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}
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ColumnPtr executeImpl(const ColumnsWithTypeAndName &, const DataTypePtr &, size_t input_rows_count) const override
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{
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size_t current_columns_number = columns_number++;
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return ColumnUInt64::create(input_rows_count, current_columns_number);
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}
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};
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}
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void registerFunctionBlockNumber(FunctionFactory & factory)
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{
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factory.registerFunction<FunctionBlockNumber>();
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}
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}
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