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#pragma once
#include "zerocopy.h"
#include "zerocopy_output.h"
#include <util/generic/string.h>
#include <util/generic/noncopyable.h>
#include <util/generic/store_policy.h>
/**
* @addtogroup Streams_Strings
* @{
*/
/**
* Input stream for reading data from a string.
*/
class TStringInput: public IZeroCopyInputFastReadTo {
public:
/**
* Constructs a string input stream that reads character data from the
* provided string.
*
* Note that this stream keeps a reference to the provided string, so it's
* up to the user to make sure that the string doesn't get destroyed while
* this stream is in use.
*
* For reading data from `TStringBuf`s, see `TMemoryInput` (`util/stream/mem.h`).
*
* @param s String to read from.
*/
inline TStringInput(const TString& s) noexcept
: S_(&s)
, Pos_(0)
{
}
TStringInput(const TString&&) = delete;
~TStringInput() override;
TStringInput(TStringInput&&) noexcept = default;
TStringInput& operator=(TStringInput&&) noexcept = default;
inline void Swap(TStringInput& s) noexcept {
DoSwap(S_, s.S_);
DoSwap(Pos_, s.Pos_);
}
protected:
size_t DoNext(const void** ptr, size_t len) override;
void DoUndo(size_t len) override;
private:
const TString* S_;
size_t Pos_;
friend class TStringStream;
};
/**
* Stream for writing data into a string.
*/
class TStringOutput: public IZeroCopyOutput {
public:
/**
* Constructs a string output stream that appends character data to the
* provided string.
*
* Note that this stream keeps a reference to the provided string, so it's
* up to the user to make sure that the string doesn't get destroyed while
* this stream is in use.
*
* @param s String to append to.
*/
inline TStringOutput(TString& s) noexcept
: S_(&s)
{
}
TStringOutput(TStringOutput&& s) noexcept = default;
~TStringOutput() override;
/**
* @param size Number of additional characters to
* reserve in output string.
*/
inline void Reserve(size_t size) {
S_->reserve(S_->size() + size);
}
inline void Swap(TStringOutput& s) noexcept {
DoSwap(S_, s.S_);
}
protected:
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;
private:
TString* S_;
};
/**
* String input/output stream, similar to `std::stringstream`.
*/
class TStringStream: private TEmbedPolicy<TString>, public TStringInput, public TStringOutput {
using TEmbeddedString = TEmbedPolicy<TString>;
public:
inline TStringStream()
: TEmbeddedString()
, TStringInput(*TEmbeddedString::Ptr())
, TStringOutput(*TEmbeddedString::Ptr())
{
}
inline TStringStream(const TString& string)
: TEmbeddedString(string)
, TStringInput(*TEmbeddedString::Ptr())
, TStringOutput(*TEmbeddedString::Ptr())
{
}
inline TStringStream(const TStringStream& other)
: TEmbeddedString(other.Str())
, TStringInput(*TEmbeddedString::Ptr())
, TStringOutput(*TEmbeddedString::Ptr())
{
}
inline TStringStream& operator=(const TStringStream& other) {
// All references remain alive, we need to change position only
Str() = other.Str();
Pos_ = other.Pos_;
return *this;
}
~TStringStream() override;
/**
* @returns Whether @c this contains any data
*/
explicit operator bool() const noexcept {
return !Empty();
}
/**
* @returns String that this stream is writing into.
*/
inline TString& Str() noexcept {
return *Ptr();
}
/**
* @returns String that this stream is writing into.
*/
inline const TString& Str() const noexcept {
return *Ptr();
}
/**
* @returns Pointer to the character data contained
* in this stream. The data is guaranteed
* to be null-terminated.
*/
inline const char* Data() const noexcept {
return Ptr()->data();
}
/**
* @returns Total number of characters in this
* stream. Note that this is not the same
* as the total number of characters
* available for reading.
*/
inline size_t Size() const noexcept {
return Ptr()->size();
}
/**
* @returns Whether the string that this stream
* operates on is empty.
*/
Y_PURE_FUNCTION inline bool Empty() const noexcept {
return Str().empty();
}
using TStringOutput::Reserve;
/**
* Clears the string that this stream operates on and resets the
* read/write pointers.
*/
inline void Clear() {
Str().clear();
Pos_ = 0;
}
// TODO: compatibility with existing code, remove
Y_PURE_FUNCTION bool empty() const {
return Empty();
}
void clear() {
Clear();
}
};
/** @} */
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