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#pragma once
#include "input.h"
#include <util/generic/buffer.h>
#include <util/generic/mem_copy.h>
#include <util/generic/strbuf.h>
#include <util/system/compiler.h>
#include <util/system/yassert.h>
/**
* @addtogroup Streams
* @{
*/
/**
* Simple stream tokenizer. Splits the stream into tokens that are available
* via iterator interface.
*
* @tparam TEndOfToken Predicate for token delimiter characters.
* @see TEol
*/
template <typename TEndOfToken>
class TStreamTokenizer {
public:
class TIterator {
public:
inline TIterator(TStreamTokenizer* const parent)
: Parent_(parent)
, AtEnd_(!Parent_->Next(Data_, Len_))
{
}
inline TIterator() noexcept
: Parent_(nullptr)
, Data_(nullptr)
, Len_(0)
, AtEnd_(true)
{
}
inline ~TIterator() = default;
inline void operator++() {
Next();
}
inline bool operator==(const TIterator& l) const noexcept {
return AtEnd_ == l.AtEnd_;
}
inline bool operator!=(const TIterator& l) const noexcept {
return !(*this == l);
}
/**
* @return Return null-terminated character array with current token.
* The pointer may be invalid after iterator increment.
*/
inline const char* Data() const noexcept {
Y_ASSERT(!AtEnd_);
return Data_;
}
/**
* @return Length of current token.
*/
inline size_t Length() const noexcept {
Y_ASSERT(!AtEnd_);
return Len_;
}
inline TIterator* operator->() noexcept {
return this;
}
inline TStringBuf operator*() noexcept {
return TStringBuf{Data_, Len_};
}
private:
inline void Next() {
Y_ASSERT(Parent_);
AtEnd_ = !Parent_->Next(Data_, Len_);
}
private:
TStreamTokenizer* const Parent_;
char* Data_;
size_t Len_;
bool AtEnd_;
};
inline TStreamTokenizer(IInputStream* const input, const TEndOfToken& eot = TEndOfToken(),
const size_t initial = 1024)
: Input_(input)
, Buf_(initial)
, Cur_(BufBegin())
, End_(BufBegin())
, Eot_(eot)
{
CheckBuf();
}
inline bool Next(char*& buf, size_t& len) {
char* it = Cur_;
while (true) {
do {
while (it != End_) {
if (Eot_(*it)) {
*it = '\0';
buf = Cur_;
len = it - Cur_;
Cur_ = it + 1;
return true;
} else {
++it;
}
}
if (Fill() == 0 && End_ != BufEnd()) {
*it = '\0';
buf = Cur_;
len = it - Cur_;
Cur_ = End_;
return len;
}
} while (it != BufEnd());
Y_ASSERT(it == BufEnd());
Y_ASSERT(End_ == BufEnd());
const size_t blen = End_ - Cur_;
if (Cur_ == BufBegin()) {
Y_ASSERT(blen == Buf_.Capacity());
/*
* do reallocate
*/
Buf_.Reserve(Buf_.Capacity() * 4);
CheckBuf();
} else {
/*
* do move
*/
MemMove(BufBegin(), Cur_, blen);
}
Cur_ = BufBegin();
End_ = Cur_ + blen;
it = End_;
}
}
inline TIterator begin() {
return TIterator{this};
}
inline TIterator end() noexcept {
return {};
}
private:
inline size_t Fill() {
const size_t avail = BufEnd() - End_;
const size_t bytesRead = Input_->Read(End_, avail);
End_ += bytesRead;
return bytesRead;
}
inline char* BufBegin() noexcept {
return Buf_.Data();
}
inline char* BufEnd() noexcept {
return Buf_.Data() + Buf_.Capacity();
}
inline void CheckBuf() const {
if (!Buf_.Data()) {
throw std::bad_alloc();
}
}
private:
IInputStream* const Input_;
TBuffer Buf_;
char* Cur_;
char* End_;
TEndOfToken Eot_;
};
/**
* Predicate for `TStreamTokenizer` that uses '\\n' as a delimiter.
*/
struct TEol {
inline bool operator()(char ch) const noexcept {
return ch == '\n';
}
};
/** @} */
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