ClickHouse/dbms/src/Functions/arrayEnumerate.cpp
2018-09-10 00:15:40 +03:00

86 lines
2.7 KiB
C++

#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypesNumber.h>
#include <Columns/ColumnArray.h>
#include <Columns/ColumnsNumber.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
/// arrayEnumerate(arr) - Returns the array [1,2,3,..., length(arr)]
class FunctionArrayEnumerate : public IFunction
{
public:
static constexpr auto name = "arrayEnumerate";
static FunctionPtr create(const Context &)
{
return std::make_shared<FunctionArrayEnumerate>();
}
String getName() const override
{
return name;
}
size_t getNumberOfArguments() const override { return 1; }
bool useDefaultImplementationForConstants() const override { return true; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
const DataTypeArray * array_type = checkAndGetDataType<DataTypeArray>(arguments[0].get());
if (!array_type)
throw Exception("First argument for function " + getName() + " must be an array but it has type "
+ arguments[0]->getName() + ".", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeArray>(std::make_shared<DataTypeUInt32>());
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t) override
{
if (const ColumnArray * array = checkAndGetColumn<ColumnArray>(block.getByPosition(arguments[0]).column.get()))
{
const ColumnArray::Offsets & offsets = array->getOffsets();
auto res_nested = ColumnUInt32::create();
ColumnUInt32::Container & res_values = res_nested->getData();
res_values.resize(array->getData().size());
ColumnArray::Offset prev_off = 0;
for (ColumnArray::Offset i = 0; i < offsets.size(); ++i)
{
ColumnArray::Offset off = offsets[i];
for (ColumnArray::Offset j = prev_off; j < off; ++j)
res_values[j] = j - prev_off + 1;
prev_off = off;
}
block.getByPosition(result).column = ColumnArray::create(std::move(res_nested), array->getOffsetsPtr());
}
else
{
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of first argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
}
};
void registerFunctionArrayEnumerate(FunctionFactory & factory)
{
factory.registerFunction<FunctionArrayEnumerate>();
}
}