ClickHouse/dbms/src/Columns/ColumnConst.cpp

#include <DB/DataTypes/FieldToDataType.h>

#include <DB/Columns/ColumnString.h>
#include <DB/Columns/ColumnConst.h>


namespace DB
{
	
template <> ColumnConst<Array>::ColumnConst(size_t s_, const Array & data_) { throw Exception("Can't create ColumnConst<Array> without nested type", ErrorCodes::LOGICAL_ERROR); }
template <> ColumnConst<Array>::ColumnConst(size_t s_, const Array & data_, DataTypePtr nested_type_) : s(s_), data(data_), nested_type(nested_type_) {}


template <> ColumnPtr ColumnConst<String>::convertToFullColumn() const
{
	ColumnString * res = new ColumnString;
	ColumnString::Offsets_t & offsets = res->getOffsets();
	ColumnUInt8::Container_t & vec = dynamic_cast<ColumnVector<UInt8> &>(res->getData()).getData();

	size_t string_size = data.size() + 1;
	size_t offset = 0;
	offsets.resize(s);
	vec.resize(s * string_size);

	for (size_t i = 0; i < s; ++i)
	{
		memcpy(&vec[offset], data.data(), string_size);
		offset += string_size;
		offsets[i] = offset;
	}

	return res;
}


template <> ColumnPtr ColumnConst<Array>::convertToFullColumn() const
{
	size_t array_size = data.size();
	ColumnPtr nested_column = nested_type->createColumn();

	ColumnArray * res = new ColumnArray(nested_column);
	ColumnArray::Offsets_t & offsets = res->getOffsets();

	offsets.resize(s);
	for (size_t i = 0; i < s; ++i)
	{
		offsets[i] = (i + 1) * array_size;
		for (size_t j = 0; j < array_size; ++j)
			nested_column->insert(data[j]);
	}

	return res;
}


}