ClickHouse/dbms/src/Functions/replicate.cpp

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#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <DataTypes/DataTypeArray.h>
#include <Columns/ColumnArray.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
}
/** Creates an array, multiplying the column (the first argument) by the number of elements in the array (the second argument).
*/
class FunctionReplicate : public IFunction
{
public:
static constexpr auto name = "replicate";
static FunctionPtr create(const Context &)
{
return std::make_shared<FunctionReplicate>();
}
String getName() const override
{
return name;
}
size_t getNumberOfArguments() const override
{
return 2;
}
bool useDefaultImplementationForNulls() const override { return false; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
const DataTypeArray * array_type = checkAndGetDataType<DataTypeArray>(arguments[1].get());
if (!array_type)
throw Exception("Second argument for function " + getName() + " must be array.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeArray>(arguments[0]);
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t) override
{
ColumnPtr first_column = block.getByPosition(arguments[0]).column;
const ColumnArray * array_column = checkAndGetColumn<ColumnArray>(block.getByPosition(arguments[1]).column.get());
ColumnPtr temp_column;
if (!array_column)
{
auto const_array_column = checkAndGetColumnConst<ColumnArray>(block.getByPosition(arguments[1]).column.get());
if (!const_array_column)
throw Exception("Unexpected column for replicate", ErrorCodes::ILLEGAL_COLUMN);
temp_column = const_array_column->convertToFullColumn();
array_column = checkAndGetColumn<ColumnArray>(temp_column.get());
}
block.getByPosition(result).column
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= ColumnArray::create(first_column->replicate(array_column->getOffsets())->convertToFullColumnIfConst(), array_column->getOffsetsPtr());
}
};
void registerFunctionReplicate(FunctionFactory & factory)
{
factory.registerFunction<FunctionReplicate>();
}
}