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#pragma once
#include <IO/BufferWithOwnMemory.h>
#include <IO/CompressionMethod.h>
#include <IO/WriteBuffer.h>
#include <IO/WriteBufferDecorator.h>
#include <zstd.h>
namespace DB
{
/// Performs compression using zstd library and writes compressed data to out_ WriteBuffer.
class ZstdDeflatingWriteBuffer : public WriteBufferWithOwnMemoryDecorator
{
public:
ZstdDeflatingWriteBuffer(
std::unique_ptr<WriteBuffer> out_,
int compression_level,
size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
char * existing_memory = nullptr,
size_t alignment = 0);
~ZstdDeflatingWriteBuffer() override;
void sync() override
{
out->sync();
}
private:
void nextImpl() override;
/// Flush all pending data and write zstd footer to the underlying buffer.
/// After the first call to this function, subsequent calls will have no effect and
/// an attempt to write to this buffer will result in exception.
void finalizeBefore() override;
void finalizeAfter() override;
void flush(ZSTD_EndDirective mode);
ZSTD_CCtx * cctx;
ZSTD_inBuffer input;
ZSTD_outBuffer output;
};
}
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