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#pragma once
#include <base/types.h>
#include <DataTypes/IDataType.h>
#include <Core/Block.h>
namespace DB
{
class WriteBuffer;
class CompressedWriteBuffer;
struct IndexForNativeFormat;
/** Serializes the stream of blocks in their native binary format (with names and column types).
* Designed for communication between servers.
*
* A stream can be specified to write the index. The index contains offsets to each part of each column.
* If an `append` is made to an existing file, and you need to write the index, then specify `initial_size_of_file`.
*/
class NativeWriter
{
public:
/** If non-zero client_revision is specified, additional block information can be written.
*/
NativeWriter(
WriteBuffer & ostr_, UInt64 client_revision_, const Block & header_, bool remove_low_cardinality_ = false,
IndexForNativeFormat * index_ = nullptr, size_t initial_size_of_file_ = 0);
Block getHeader() const { return header; }
/// Returns the number of bytes written.
size_t write(const Block & block);
void flush();
static String getContentType() { return "application/octet-stream"; }
private:
WriteBuffer & ostr;
UInt64 client_revision;
Block header;
IndexForNativeFormat * index = nullptr;
size_t initial_size_of_file; /// The initial size of the data file, if `append` done. Used for the index.
/// If you need to write index, then `ostr` must be a CompressedWriteBuffer.
CompressedWriteBuffer * ostr_concrete = nullptr;
bool remove_low_cardinality;
};
}
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