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#pragma once
#include "zerocopy.h"
#include "zerocopy_output.h"
#include <util/generic/strbuf.h>
/**
* @addtogroup Streams_Memory
* @{
*/
/**
* Input stream that reads data from a memory block.
*/
class TMemoryInput: public IZeroCopyInputFastReadTo {
public:
TMemoryInput() noexcept;
/**
* Constructs a stream that reads from the provided memory block. It's up
* to the user to make sure that the memory block doesn't get freed while
* this stream is in use.
*
* @param buf Memory block to use.
* @param len Size of the memory block.
*/
TMemoryInput(const void* buf, size_t len) noexcept;
explicit TMemoryInput(const TStringBuf buf) noexcept;
~TMemoryInput() override;
TMemoryInput(const TMemoryInput& other) noexcept
: IZeroCopyInputFastReadTo()
, Buf_(other.Buf_)
, Len_(other.Len_)
{
}
TMemoryInput& operator=(const TMemoryInput& other) noexcept {
if (this != &other) {
Buf_ = other.Buf_;
Len_ = other.Len_;
}
return *this;
}
TMemoryInput(TMemoryInput&&) noexcept = default;
TMemoryInput& operator=(TMemoryInput&&) noexcept = default;
/**
* Initializes this stream with a new memory block. It's up to the
* user to make sure that the memory block doesn't get freed while this
* stream is in use.
*
* @param buf New memory block to use.
* @param len Size of the new memory block.
*/
void Reset(const void* buf, size_t len) noexcept {
Buf_ = (const char*)buf;
Len_ = len;
}
/**
* @returns Whether there is more data in the stream.
*/
bool Exhausted() const noexcept {
return !Avail();
}
/**
* @returns Number of bytes available in the stream.
*/
size_t Avail() const noexcept {
return Len_;
}
/**
* @returns Current read position in the memory block
* used by this stream.
*/
const char* Buf() const noexcept {
return Buf_;
}
/**
* Initializes this stream with a next chunk extracted from the given zero
* copy stream.
*
* @param stream Zero copy stream to initialize from.
*/
void Fill(IZeroCopyInput* stream) {
Len_ = stream->Next(&Buf_);
if (!Len_) {
Reset(nullptr, 0);
}
}
private:
size_t DoNext(const void** ptr, size_t len) override;
void DoUndo(size_t len) override;
private:
const char* Buf_;
size_t Len_;
};
/**
* Output stream that writes data to a memory block.
*/
class TMemoryOutput: public IZeroCopyOutput {
public:
/**
* Constructs a stream that writes to the provided memory block. It's up
* to the user to make sure that the memory block doesn't get freed while
* this stream is in use.
*
* @param buf Memory block to use.
* @param len Size of the memory block.
*/
TMemoryOutput(void* buf, size_t len) noexcept
: Buf_(static_cast<char*>(buf))
, End_(Buf_ + len)
{
}
~TMemoryOutput() override;
TMemoryOutput(TMemoryOutput&&) noexcept = default;
TMemoryOutput& operator=(TMemoryOutput&&) noexcept = default;
/**
* Initializes this stream with a new memory block. It's up to the
* user to make sure that the memory block doesn't get freed while this
* stream is in use.
*
* @param buf New memory block to use.
* @param len Size of the new memory block.
*/
inline void Reset(void* buf, size_t len) noexcept {
Buf_ = static_cast<char*>(buf);
End_ = Buf_ + len;
}
/**
* @returns Whether there is more space in the
* stream for writing.
*/
inline bool Exhausted() const noexcept {
return !Avail();
}
/**
* @returns Number of bytes available for writing
* in the stream.
*/
inline size_t Avail() const noexcept {
return End_ - Buf_;
}
/**
* @returns Current write position in the memory block
* used by this stream.
*/
inline char* Buf() const noexcept {
return Buf_;
}
/**
* @returns Pointer to the end of the memory block
* used by this stream.
*/
char* End() const {
return End_;
}
private:
size_t DoNext(void** ptr) override;
void DoUndo(size_t len) override;
void DoWrite(const void* buf, size_t len) override;
void DoWriteC(char c) override;
protected:
char* Buf_;
char* End_;
};
/**
* Memory output stream that supports changing the position of the
* write pointer.
*
* @see TMemoryOutput
*/
class TMemoryWriteBuffer: public TMemoryOutput {
public:
TMemoryWriteBuffer(void* buf, size_t len)
: TMemoryOutput(buf, len)
, Beg_(Buf_)
{
}
void Reset(void* buf, size_t len) {
TMemoryOutput::Reset(buf, len);
Beg_ = Buf_;
}
size_t Len() const {
return Buf() - Beg();
}
size_t Empty() const {
return Buf() == Beg();
}
/**
* @returns Data that has been written into this
* stream as a string.
*/
TStringBuf Str() const {
return TStringBuf(Beg(), Buf());
}
char* Beg() const {
return Beg_;
}
/**
* @param ptr New write position for this stream.
* Must be inside the memory block that
* this stream uses.
*/
void SetPos(char* ptr) {
Y_ASSERT(Beg_ <= ptr);
SetPosImpl(ptr);
}
/**
* @param pos New write position for this stream,
* relative to the beginning of the memory
* block that this stream uses.
*/
void SetPos(size_t pos) {
SetPosImpl(Beg_ + pos);
}
protected:
void SetPosImpl(char* ptr) {
Y_ASSERT(End_ >= ptr);
Buf_ = ptr;
}
protected:
char* Beg_;
};
/** @} */
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