ClickHouse/dbms/include/DB/Functions/FunctionsFormatting.h

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#include <DB/Functions/IFunction.h>
#include "NumberTraits.h"
#include <DB/Columns/ColumnString.h>
#include <DB/DataTypes/DataTypesNumberFixed.h>
#include <DB/IO/WriteBufferFromVector.h>
#include <DB/IO/WriteBufferFromString.h>
namespace DB
{
/** Функция для необычного преобразования в строку:
*
* bitmaskToList - принимает целое число - битовую маску, возвращает строку из степеней двойки через запятую.
* например, bitmaskToList(50) = '2,16,32'
*/
class FunctionBitmaskToList : public IFunction
{
public:
/// Получить основное имя функции.
virtual String getName() const
{
return "bitmaskToList";
}
/// Получить тип результата по типам аргументов. Если функция неприменима для данных аргументов - кинуть исключение.
virtual DataTypePtr getReturnType(const DataTypes & arguments) const
{
if (arguments.size() != 1)
throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
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+ toString(arguments.size()) + ", should be 1.",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
const IDataType * type = &*arguments[0];
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if (!dynamic_cast<const DataTypeUInt8 *>(type) &&
!dynamic_cast<const DataTypeUInt16 *>(type) &&
!dynamic_cast<const DataTypeUInt32 *>(type) &&
!dynamic_cast<const DataTypeUInt64 *>(type) &&
!dynamic_cast<const DataTypeInt8 *>(type) &&
!dynamic_cast<const DataTypeInt16 *>(type) &&
!dynamic_cast<const DataTypeInt32 *>(type) &&
!dynamic_cast<const DataTypeInt64 *>(type))
throw Exception("Cannot format " + type->getName() + " as bitmask string", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return new DataTypeString;
}
template<typename T>
inline static void writeBitmask(T x, WriteBuffer & out)
{
bool first = true;
while (x)
{
T y = (x & (x - 1));
T bit = x ^ y;
x = y;
if (!first)
out.write(",", 1);
first = false;
writeIntText(bit, out);
}
}
template<typename T>
bool executeType(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (const ColumnVector<T> * col_from = dynamic_cast<const ColumnVector<T> *>(&*block.getByPosition(arguments[0]).column))
{
ColumnString * col_to = new ColumnString;
block.getByPosition(result).column = col_to;
const typename ColumnVector<T>::Container_t & vec_from = col_from->getData();
ColumnString::Chars_t & data_to = col_to->getChars();
ColumnString::Offsets_t & offsets_to = col_to->getOffsets();
size_t size = vec_from.size();
data_to.resize(size * 2);
offsets_to.resize(size);
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WriteBufferFromVector<ColumnString::Chars_t> buf_to(data_to);
for (size_t i = 0; i < size; ++i)
{
writeBitmask<T>(vec_from[i], buf_to);
writeChar(0, buf_to);
offsets_to[i] = buf_to.count();
}
data_to.resize(buf_to.count());
}
else if (const ColumnConst<T> * col_from = dynamic_cast<const ColumnConst<T> *>(&*block.getByPosition(arguments[0]).column))
{
std::string res;
{
WriteBufferFromString buf(res);
writeBitmask<T>(col_from->getData(), buf);
}
block.getByPosition(result).column = new ColumnConstString(col_from->size(), res);
}
else
{
return false;
}
return true;
}
/// Выполнить функцию над блоком.
void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (!( executeType<UInt8>(block, arguments, result)
|| executeType<UInt16>(block, arguments, result)
|| executeType<UInt32>(block, arguments, result)
|| executeType<UInt64>(block, arguments, result)
|| executeType<Int8>(block, arguments, result)
|| executeType<Int16>(block, arguments, result)
|| executeType<Int32>(block, arguments, result)
|| executeType<Int64>(block, arguments, result)))
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
private:
};
}