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#pragma once
#include "zerocopy.h"
#include "zerocopy_output.h"
#include <utility>
#include <util/generic/ptr.h>
#include <util/generic/typetraits.h>
#include <util/generic/store_policy.h>
/**
* @addtogroup Streams_Buffered
* @{
*/
/**
* Input stream that wraps the given stream and adds a buffer on top of it,
* thus making sure that data is read from the underlying stream in big chunks.
*
* Note that it does not claim ownership of the underlying stream, so it's up
* to the user to free it.
*/
class TBufferedInput: public IZeroCopyInput {
public:
TBufferedInput(IInputStream* slave, size_t buflen = 8192);
TBufferedInput(TBufferedInput&&) noexcept;
TBufferedInput& operator=(TBufferedInput&&) noexcept;
~TBufferedInput() override;
/**
* Switches the underlying stream to the one provided. Does not clear the
* data that was already buffered.
*
* @param slave New underlying stream.
*/
void Reset(IInputStream* slave);
protected:
size_t DoRead(void* buf, size_t len) override;
size_t DoReadTo(TString& st, char ch) override;
size_t DoSkip(size_t len) override;
size_t DoNext(const void** ptr, size_t len) override;
private:
class TImpl;
THolder<TImpl> Impl_;
};
/**
* Output stream that wraps the given stream and adds a buffer on top of it,
* thus making sure that data is written to the underlying stream in big chunks.
*
* Note that by default this stream does not propagate `Flush` and `Finish`
* calls to the underlying stream, instead simply flushing out the buffer.
* You can change this behavior by using propagation mode setters.
*
* Also note that this stream does not claim ownership of the underlying stream,
* so it's up to the user to free it.
*/
class TBufferedOutputBase: public IZeroCopyOutput {
public:
/**
* Constructs a buffered stream that dynamically adjusts the size of the
* buffer. This works best when the amount of data that will be passed
* through this stream is not known and can range in size from several
* kilobytes to several gigabytes.
*
* @param slave Underlying stream.
*/
TBufferedOutputBase(IOutputStream* slave);
/**
* Constructs a buffered stream with the given size of the buffer.
*
* @param slave Underlying stream.
* @param buflen Size of the buffer.
*/
TBufferedOutputBase(IOutputStream* slave, size_t buflen);
TBufferedOutputBase(TBufferedOutputBase&&) noexcept;
TBufferedOutputBase& operator=(TBufferedOutputBase&&) noexcept;
~TBufferedOutputBase() override;
/**
* @param propagate Whether `Flush` and `Finish` calls should
* be propagated to the underlying stream.
* By default they are not.
*/
inline void SetPropagateMode(bool propagate) noexcept {
SetFlushPropagateMode(propagate);
SetFinishPropagateMode(propagate);
}
/**
* @param propagate Whether `Flush` calls should be propagated
* to the underlying stream. By default they
* are not.
*/
void SetFlushPropagateMode(bool propagate) noexcept;
/**
* @param propagate Whether `Finish` calls should be propagated
* to the underlying stream. By default they
* are not.
*/
void SetFinishPropagateMode(bool propagate) noexcept;
class TImpl;
protected:
size_t DoNext(void** ptr) override;
void DoUndo(size_t len) override;
void DoWrite(const void* data, size_t len) override;
void DoWriteC(char c) override;
void DoFlush() override;
void DoFinish() override;
private:
THolder<TImpl> Impl_;
};
/**
* Buffered output stream with a fixed-size buffer.
*
* @see TBufferedOutputBase
*/
class TBufferedOutput: public TBufferedOutputBase {
public:
TBufferedOutput(IOutputStream* slave, size_t buflen = 8192);
~TBufferedOutput() override;
TBufferedOutput(TBufferedOutput&&) noexcept = default;
TBufferedOutput& operator=(TBufferedOutput&&) noexcept = default;
};
/**
* Buffered output stream that dynamically adjusts the size of the buffer based
* on the amount of data that's passed through it.
*
* @see TBufferedOutputBase
*/
class TAdaptiveBufferedOutput: public TBufferedOutputBase {
public:
TAdaptiveBufferedOutput(IOutputStream* slave);
~TAdaptiveBufferedOutput() override;
TAdaptiveBufferedOutput(TAdaptiveBufferedOutput&&) noexcept = default;
TAdaptiveBufferedOutput& operator=(TAdaptiveBufferedOutput&&) noexcept = default;
};
namespace NPrivate {
struct TMyBufferedOutput: public TBufferedOutput {
inline TMyBufferedOutput(IOutputStream* slave, size_t buflen)
: TBufferedOutput(slave, buflen)
{
SetFinishPropagateMode(true);
}
};
template <class T>
struct TBufferedStreamFor {
using TResult = std::conditional_t<std::is_base_of<IInputStream, T>::value, TBufferedInput, TMyBufferedOutput>;
};
}
/**
* A mixin class that turns unbuffered stream into a buffered one.
*
* Note that using this mixin with a stream that is already buffered won't
* result in double buffering, e.g. `TBuffered<TBuffered<TUnbufferedFileInput>>` and
* `TBuffered<TUnbufferedFileInput>` are basically the same types.
*
* Example usage:
* @code
* TBuffered<TUnbufferedFileInput> file_input(1024, "/path/to/file");
* TBuffered<TUnbufferedFileOutput> file_output(1024, "/path/to/file");
* @endcode
* Here 1024 is the size of the buffer.
*/
template <class TSlave>
class TBuffered: private TEmbedPolicy<TSlave>, public ::NPrivate::TBufferedStreamFor<TSlave>::TResult {
using TSlaveBase = TEmbedPolicy<TSlave>;
using TBufferedBase = typename ::NPrivate::TBufferedStreamFor<TSlave>::TResult;
public:
template <typename... Args>
inline TBuffered(size_t b, Args&&... args)
: TSlaveBase(std::forward<Args>(args)...)
, TBufferedBase(TSlaveBase::Ptr(), b)
{
}
inline TSlave& Slave() noexcept {
return *this->Ptr();
}
TBuffered(const TBuffered&) = delete;
TBuffered& operator=(const TBuffered&) = delete;
TBuffered(TBuffered&&) = delete;
TBuffered& operator=(TBuffered&&) = delete;
};
/**
* A mixin class that turns unbuffered stream into an adaptively buffered one.
* Created stream differs from the one created via `TBuffered` template in that
* it dynamically adjusts the size of the buffer based on the amount of data
* that's passed through it.
*
* Example usage:
* @code
* TAdaptivelyBuffered<TUnbufferedFileOutput> file_output("/path/to/file");
* @endcode
*/
template <class TSlave>
class TAdaptivelyBuffered: private TEmbedPolicy<TSlave>, public TAdaptiveBufferedOutput {
using TSlaveBase = TEmbedPolicy<TSlave>;
public:
template <typename... Args>
inline TAdaptivelyBuffered(Args&&... args)
: TSlaveBase(std::forward<Args>(args)...)
, TAdaptiveBufferedOutput(TSlaveBase::Ptr())
{
}
TAdaptivelyBuffered(const TAdaptivelyBuffered&) = delete;
TAdaptivelyBuffered& operator=(const TAdaptivelyBuffered&) = delete;
TAdaptivelyBuffered(TAdaptivelyBuffered&& other) = delete;
TAdaptivelyBuffered& operator=(TAdaptivelyBuffered&& other) = delete;
};
/** @} */
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