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83 lines
2.6 KiB
C++
83 lines
2.6 KiB
C++
#include <Functions/IFunction.h>
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#include <Functions/GatherUtils/GatherUtils.h>
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#include <DataTypes/DataTypeArray.h>
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#include <Columns/ColumnArray.h>
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#include <Common/typeid_cast.h>
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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 LOGICAL_ERROR;
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extern const int ILLEGAL_TYPE_OF_ARGUMENT;
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}
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class FunctionArrayPop : public IFunction
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{
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public:
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FunctionArrayPop(bool pop_front, const char * name) : pop_front(pop_front), name(name) {}
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String getName() const override { return name; }
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bool isVariadic() const override { return false; }
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size_t getNumberOfArguments() const override { return 1; }
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DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
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{
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if (arguments[0]->onlyNull())
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return arguments[0];
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auto array_type = typeid_cast<const DataTypeArray *>(arguments[0].get());
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if (!array_type)
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throw Exception("First argument for function " + getName() + " must be an array but it has type "
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+ arguments[0]->getName() + ".", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
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return arguments[0];
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}
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void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t input_rows_count) override
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{
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const auto & return_type = block.getByPosition(result).type;
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if (return_type->onlyNull())
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{
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block.getByPosition(result).column = return_type->createColumnConstWithDefaultValue(input_rows_count);
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return;
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}
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auto result_column = return_type->createColumn();
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const auto & array_column = block.getByPosition(arguments[0]).column;
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std::unique_ptr<GatherUtils::IArraySource> source;
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size_t size = array_column->size();
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if (auto argument_column_array = typeid_cast<const ColumnArray *>(array_column.get()))
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source = GatherUtils::createArraySource(*argument_column_array, false, size);
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else
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throw Exception{"First arguments for function " + getName() + " must be array.", ErrorCodes::LOGICAL_ERROR};
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auto sink = GatherUtils::createArraySink(typeid_cast<ColumnArray &>(*result_column), size);
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if (pop_front)
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GatherUtils::sliceFromLeftConstantOffsetUnbounded(*source, *sink, 1);
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else
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GatherUtils::sliceFromLeftConstantOffsetBounded(*source, *sink, 0, -1);
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block.getByPosition(result).column = std::move(result_column);
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}
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bool useDefaultImplementationForConstants() const override { return true; }
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bool useDefaultImplementationForNulls() const override { return false; }
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private:
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bool pop_front;
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const char * name;
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};
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}
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