ClickHouse/dbms/DataTypes/DataTypeNothing.cpp

#include <Common/typeid_cast.h>
#include <DataTypes/DataTypeNothing.h>
#include <DataTypes/DataTypeFactory.h>
#include <Columns/ColumnNothing.h>
#include <IO/ReadBuffer.h>
#include <IO/WriteBuffer.h>


namespace DB
{

MutableColumnPtr DataTypeNothing::createColumn() const
{
    return ColumnNothing::create(0);
}

void DataTypeNothing::serializeBinaryBulk(const IColumn & column, WriteBuffer & ostr, size_t offset, size_t limit) const
{
    size_t size = column.size();

    if (limit == 0 || offset + limit > size)
        limit = size - offset;

    for (size_t i = 0; i < limit; ++i)
        ostr.write('0');
}

void DataTypeNothing::deserializeBinaryBulk(IColumn & column, ReadBuffer & istr, size_t limit, double /*avg_value_size_hint*/) const
{
    typeid_cast<ColumnNothing &>(column).addSize(istr.tryIgnore(limit));
}

bool DataTypeNothing::equals(const IDataType & rhs) const
{
    return typeid(rhs) == typeid(*this);
}


void registerDataTypeNothing(DataTypeFactory & factory)
{
    factory.registerSimpleDataType("Nothing", [] { return DataTypePtr(std::make_shared<DataTypeNothing>()); });
}

}