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#pragma once
#include "blob.h"
#include <library/cpp/yt/memory/ref.h>
#include <util/stream/zerocopy_output.h>
#include <util/generic/size_literals.h>
namespace NYT {
////////////////////////////////////////////////////////////////////////////////
struct TDefaultChunkedOutputStreamTag
{ };
class TChunkedOutputStream
: public IZeroCopyOutput
{
public:
explicit TChunkedOutputStream(
TRefCountedTypeCookie tagCookie = GetRefCountedTypeCookie<TDefaultChunkedOutputStreamTag>(),
size_t initialReserveSize = 4_KB,
size_t maxReserveSize = 64_KB);
TChunkedOutputStream(TChunkedOutputStream&&) = default;
TChunkedOutputStream& operator=(TChunkedOutputStream&&) = default;
//! Returns a sequence of written chunks.
//! The stream is no longer usable after this call.
std::vector<TSharedRef> Finish();
//! Returns the number of bytes actually written.
size_t GetSize() const;
//! Returns the number of bytes actually written plus unused capacity in the
//! last chunk.
size_t GetCapacity() const;
//! Returns a pointer to a contiguous memory block of a given #size.
//! Do not forget to call #Advance after use.
char* Preallocate(size_t size);
//! Marks #size bytes (which were previously preallocated) as used.
void Advance(size_t size);
private:
size_t MaxReserveSize_;
size_t CurrentReserveSize_;
size_t FinishedSize_ = 0;
TBlob CurrentChunk_;
std::vector<TSharedRef> FinishedChunks_;
void ReserveNewChunk(size_t spaceRequired);
void DoWrite(const void* buf, size_t len) override;
size_t DoNext(void** ptr) override;
void DoUndo(size_t len) override;
};
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT
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