Back to home page

EIC code displayed by LXR

 
 

    


Warning, /include/c++/v1/fstream is written in an unsupported language. File is not indexed.

0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009 
0010 #ifndef _LIBCPP_FSTREAM
0011 #define _LIBCPP_FSTREAM
0012 
0013 /*
0014     fstream synopsis
0015 
0016 template <class charT, class traits = char_traits<charT> >
0017 class basic_filebuf
0018     : public basic_streambuf<charT, traits>
0019 {
0020 public:
0021     typedef charT                          char_type;
0022     typedef traits                         traits_type;
0023     typedef typename traits_type::int_type int_type;
0024     typedef typename traits_type::pos_type pos_type;
0025     typedef typename traits_type::off_type off_type;
0026 
0027     // 27.9.1.2 Constructors/destructor:
0028     basic_filebuf();
0029     basic_filebuf(basic_filebuf&& rhs);
0030     virtual ~basic_filebuf();
0031 
0032     // 27.9.1.3 Assign/swap:
0033     basic_filebuf& operator=(basic_filebuf&& rhs);
0034     void swap(basic_filebuf& rhs);
0035 
0036     // 27.9.1.4 Members:
0037     bool is_open() const;
0038     basic_filebuf* open(const char* s, ios_base::openmode mode);
0039     basic_filebuf* open(const string& s, ios_base::openmode mode);
0040     basic_filebuf* open(const filesystem::path& p, ios_base::openmode mode); // C++17
0041     basic_filebuf* close();
0042 
0043 protected:
0044     // 27.9.1.5 Overridden virtual functions:
0045     virtual streamsize showmanyc();
0046     virtual int_type underflow();
0047     virtual int_type uflow();
0048     virtual int_type pbackfail(int_type c = traits_type::eof());
0049     virtual int_type overflow (int_type c = traits_type::eof());
0050     virtual basic_streambuf<char_type, traits_type>* setbuf(char_type* s, streamsize n);
0051     virtual pos_type seekoff(off_type off, ios_base::seekdir way,
0052                              ios_base::openmode which = ios_base::in | ios_base::out);
0053     virtual pos_type seekpos(pos_type sp,
0054                              ios_base::openmode which = ios_base::in | ios_base::out);
0055     virtual int sync();
0056     virtual void imbue(const locale& loc);
0057 };
0058 
0059 template <class charT, class traits>
0060   void
0061   swap(basic_filebuf<charT, traits>& x, basic_filebuf<charT, traits>& y);
0062 
0063 typedef basic_filebuf<char>    filebuf;
0064 typedef basic_filebuf<wchar_t> wfilebuf;
0065 
0066 template <class charT, class traits = char_traits<charT> >
0067 class basic_ifstream
0068     : public basic_istream<charT,traits>
0069 {
0070 public:
0071     typedef charT                          char_type;
0072     typedef traits                         traits_type;
0073     typedef typename traits_type::int_type int_type;
0074     typedef typename traits_type::pos_type pos_type;
0075     typedef typename traits_type::off_type off_type;
0076     using native_handle_type = typename basic_filebuf<charT, traits>::native_handle_type; // Since C++26
0077 
0078     basic_ifstream();
0079     explicit basic_ifstream(const char* s, ios_base::openmode mode = ios_base::in);
0080     explicit basic_ifstream(const string& s, ios_base::openmode mode = ios_base::in);
0081     template<class T>
0082     explicit basic_ifstream(const T& s, ios_base::openmode mode = ios_base::in); // Since C++17
0083     basic_ifstream(basic_ifstream&& rhs);
0084 
0085     basic_ifstream& operator=(basic_ifstream&& rhs);
0086     void swap(basic_ifstream& rhs);
0087 
0088     basic_filebuf<char_type, traits_type>* rdbuf() const;
0089     native_handle_type native_handle() const noexcept; // Since C++26
0090     bool is_open() const;
0091     void open(const char* s, ios_base::openmode mode = ios_base::in);
0092     void open(const string& s, ios_base::openmode mode = ios_base::in);
0093     void open(const filesystem::path& s, ios_base::openmode mode = ios_base::in); // C++17
0094 
0095     void close();
0096 };
0097 
0098 template <class charT, class traits>
0099   void
0100   swap(basic_ifstream<charT, traits>& x, basic_ifstream<charT, traits>& y);
0101 
0102 typedef basic_ifstream<char>    ifstream;
0103 typedef basic_ifstream<wchar_t> wifstream;
0104 
0105 template <class charT, class traits = char_traits<charT> >
0106 class basic_ofstream
0107     : public basic_ostream<charT,traits>
0108 {
0109 public:
0110     typedef charT                          char_type;
0111     typedef traits                         traits_type;
0112     typedef typename traits_type::int_type int_type;
0113     typedef typename traits_type::pos_type pos_type;
0114     typedef typename traits_type::off_type off_type;
0115     using native_handle_type = typename basic_filebuf<charT, traits>::native_handle_type; // Since C++26
0116 
0117     basic_ofstream();
0118     explicit basic_ofstream(const char* s, ios_base::openmode mode = ios_base::out);
0119     explicit basic_ofstream(const string& s, ios_base::openmode mode = ios_base::out);
0120     template<class T>
0121     explicit basic_ofstream(const T& s, ios_base::openmode mode = ios_base::out); // Since C++17
0122     basic_ofstream(basic_ofstream&& rhs);
0123 
0124     basic_ofstream& operator=(basic_ofstream&& rhs);
0125     void swap(basic_ofstream& rhs);
0126 
0127     basic_filebuf<char_type, traits_type>* rdbuf() const;
0128     native_handle_type native_handle() const noexcept; // Since C++26
0129 
0130     bool is_open() const;
0131     void open(const char* s, ios_base::openmode mode = ios_base::out);
0132     void open(const string& s, ios_base::openmode mode = ios_base::out);
0133     void open(const filesystem::path& p,
0134               ios_base::openmode mode = ios_base::out); // C++17
0135 
0136     void close();
0137 };
0138 
0139 template <class charT, class traits>
0140   void
0141   swap(basic_ofstream<charT, traits>& x, basic_ofstream<charT, traits>& y);
0142 
0143 typedef basic_ofstream<char>    ofstream;
0144 typedef basic_ofstream<wchar_t> wofstream;
0145 
0146 template <class charT, class traits=char_traits<charT> >
0147 class basic_fstream
0148     : public basic_iostream<charT,traits>
0149 {
0150 public:
0151     typedef charT                          char_type;
0152     typedef traits                         traits_type;
0153     typedef typename traits_type::int_type int_type;
0154     typedef typename traits_type::pos_type pos_type;
0155     typedef typename traits_type::off_type off_type;
0156     using native_handle_type = typename basic_filebuf<charT, traits>::native_handle_type; // Since C++26
0157 
0158     basic_fstream();
0159     explicit basic_fstream(const char* s, ios_base::openmode mode = ios_base::in|ios_base::out);
0160     explicit basic_fstream(const string& s, ios_base::openmode mode = ios_base::in|ios_base::out);
0161     template<class T>
0162     explicit basic_fstream(const T& s, ios_base::openmode mode = ios_base::in | ios_base::out); // Since C++17
0163     basic_fstream(basic_fstream&& rhs);
0164 
0165     basic_fstream& operator=(basic_fstream&& rhs);
0166     void swap(basic_fstream& rhs);
0167 
0168     basic_filebuf<char_type, traits_type>* rdbuf() const;
0169     native_handle_type native_handle() const noexcept; // Since C++26
0170     bool is_open() const;
0171     void open(const char* s, ios_base::openmode mode = ios_base::in|ios_base::out);
0172     void open(const string& s, ios_base::openmode mode = ios_base::in|ios_base::out);
0173     void open(const filesystem::path& s,
0174               ios_base::openmode mode = ios_base::in|ios_base::out); // C++17
0175 
0176     void close();
0177 };
0178 
0179 template <class charT, class traits>
0180   void swap(basic_fstream<charT, traits>& x, basic_fstream<charT, traits>& y);
0181 
0182 typedef basic_fstream<char>    fstream;
0183 typedef basic_fstream<wchar_t> wfstream;
0184 
0185 }  // std
0186 
0187 */
0188 
0189 #if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
0190 #  include <__cxx03/fstream>
0191 #else
0192 #  include <__config>
0193 
0194 #  if _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION
0195 
0196 #    include <__algorithm/max.h>
0197 #    include <__assert>
0198 #    include <__filesystem/path.h>
0199 #    include <__fwd/fstream.h>
0200 #    include <__locale>
0201 #    include <__memory/addressof.h>
0202 #    include <__memory/unique_ptr.h>
0203 #    include <__ostream/basic_ostream.h>
0204 #    include <__type_traits/enable_if.h>
0205 #    include <__type_traits/is_same.h>
0206 #    include <__utility/move.h>
0207 #    include <__utility/swap.h>
0208 #    include <__utility/unreachable.h>
0209 #    include <cstdio>
0210 #    include <istream>
0211 #    include <streambuf>
0212 #    include <typeinfo>
0213 #    include <version>
0214 
0215 #    if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0216 #      pragma GCC system_header
0217 #    endif
0218 
0219 _LIBCPP_PUSH_MACROS
0220 #    include <__undef_macros>
0221 
0222 _LIBCPP_BEGIN_NAMESPACE_STD
0223 
0224 #    if _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_WIN32API)
0225 _LIBCPP_EXPORTED_FROM_ABI void* __filebuf_windows_native_handle(FILE* __file) noexcept;
0226 #    endif
0227 
0228 template <class _CharT, class _Traits>
0229 class _LIBCPP_TEMPLATE_VIS basic_filebuf : public basic_streambuf<_CharT, _Traits> {
0230 public:
0231   typedef _CharT char_type;
0232   typedef _Traits traits_type;
0233   typedef typename traits_type::int_type int_type;
0234   typedef typename traits_type::pos_type pos_type;
0235   typedef typename traits_type::off_type off_type;
0236   typedef typename traits_type::state_type state_type;
0237 #    if _LIBCPP_STD_VER >= 26
0238 #      if defined(_LIBCPP_WIN32API)
0239   using native_handle_type = void*; // HANDLE
0240 #      elif __has_include(<unistd.h>)
0241   using native_handle_type = int; // POSIX file descriptor
0242 #      else
0243 #        error "Provide a native file handle!"
0244 #      endif
0245 #    endif
0246 
0247   // 27.9.1.2 Constructors/destructor:
0248   basic_filebuf();
0249   basic_filebuf(basic_filebuf&& __rhs);
0250   ~basic_filebuf() override;
0251 
0252   // 27.9.1.3 Assign/swap:
0253   _LIBCPP_HIDE_FROM_ABI basic_filebuf& operator=(basic_filebuf&& __rhs);
0254   void swap(basic_filebuf& __rhs);
0255 
0256   // 27.9.1.4 Members:
0257   _LIBCPP_HIDE_FROM_ABI bool is_open() const;
0258   basic_filebuf* open(const char* __s, ios_base::openmode __mode);
0259 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
0260   basic_filebuf* open(const wchar_t* __s, ios_base::openmode __mode);
0261 #    endif
0262   _LIBCPP_HIDE_FROM_ABI basic_filebuf* open(const string& __s, ios_base::openmode __mode);
0263 
0264 #    if _LIBCPP_STD_VER >= 17
0265   _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI basic_filebuf*
0266   open(const filesystem::path& __p, ios_base::openmode __mode) {
0267     return open(__p.c_str(), __mode);
0268   }
0269 #    endif
0270   _LIBCPP_HIDE_FROM_ABI basic_filebuf* __open(int __fd, ios_base::openmode __mode);
0271   basic_filebuf* close();
0272 #    if _LIBCPP_STD_VER >= 26
0273   _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() const noexcept {
0274     _LIBCPP_ASSERT_UNCATEGORIZED(this->is_open(), "File must be opened");
0275 #      if defined(_LIBCPP_WIN32API)
0276     return std::__filebuf_windows_native_handle(__file_);
0277 #      elif __has_include(<unistd.h>)
0278     return fileno(__file_);
0279 #      else
0280 #        error "Provide a way to determine the file native handle!"
0281 #      endif
0282   }
0283 #    endif //  _LIBCPP_STD_VER >= 26
0284 
0285   _LIBCPP_HIDE_FROM_ABI inline static const char* __make_mdstring(ios_base::openmode __mode) _NOEXCEPT;
0286 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
0287   _LIBCPP_HIDE_FROM_ABI inline static const wchar_t* __make_mdwstring(ios_base::openmode __mode) _NOEXCEPT;
0288 #    endif
0289 
0290 protected:
0291   // 27.9.1.5 Overridden virtual functions:
0292   int_type underflow() override;
0293   int_type pbackfail(int_type __c = traits_type::eof()) override;
0294   int_type overflow(int_type __c = traits_type::eof()) override;
0295   basic_streambuf<char_type, traits_type>* setbuf(char_type* __s, streamsize __n) override;
0296   pos_type
0297   seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __wch = ios_base::in | ios_base::out) override;
0298   pos_type seekpos(pos_type __sp, ios_base::openmode __wch = ios_base::in | ios_base::out) override;
0299   int sync() override;
0300   void imbue(const locale& __loc) override;
0301 
0302 private:
0303   char* __extbuf_;
0304   const char* __extbufnext_;
0305   const char* __extbufend_;
0306   char __extbuf_min_[8];
0307   size_t __ebs_;
0308   char_type* __intbuf_;
0309   size_t __ibs_;
0310   FILE* __file_;
0311   const codecvt<char_type, char, state_type>* __cv_;
0312   state_type __st_;
0313   state_type __st_last_;
0314   ios_base::openmode __om_;
0315   // There have been no file operations yet, which allows setting unbuffered
0316   // I/O mode.
0317   static const ios_base::openmode __no_io_operations = ios_base::trunc;
0318   // Unbuffered I/O mode has been requested.
0319   static const ios_base::openmode __use_unbuffered_io = ios_base::ate;
0320   // Used to track the currently used mode and track whether the output should
0321   // be unbuffered.
0322   // [filebuf.virtuals]/12
0323   //   If setbuf(0, 0) is called on a stream before any I/O has occurred on
0324   //   that stream, the stream becomes unbuffered. Otherwise the results are
0325   //   implementation-defined.
0326   // This allows calling setbuf(0, 0)
0327   // - before opening a file,
0328   // - after opening a file, before
0329   //   - a read
0330   //   - a write
0331   //   - a seek.
0332   // Note that opening a file with ios_base::ate does a seek operation.
0333   // Normally underflow, overflow, and sync change this flag to ios_base::in,
0334   // ios_base_out, or 0.
0335   //
0336   // The ios_base::trunc and ios_base::ate flags are not used in __cm_. They
0337   // are used to track the state of the unbuffered request. For readability
0338   // they have the aliases __no_io_operations and __use_unbuffered_io
0339   // respectively.
0340   //
0341   // The __no_io_operations and __use_unbuffered_io flags are used in the
0342   // following way:
0343   // - __no_io_operations is set upon construction to indicate the unbuffered
0344   //   state can be set.
0345   // - When requesting unbuffered output:
0346   //   - If the file is open it sets the mode.
0347   //   - Else places a request by adding the __use_unbuffered_io flag.
0348   // - When a file is opened it checks whether both __no_io_operations and
0349   //   __use_unbuffered_io are set. If so switches to unbuffered mode.
0350   // - All file I/O operations change the mode effectively clearing the
0351   //   __no_io_operations and __use_unbuffered_io flags.
0352   ios_base::openmode __cm_;
0353   bool __owns_eb_;
0354   bool __owns_ib_;
0355   bool __always_noconv_;
0356 
0357   bool __read_mode();
0358   void __write_mode();
0359 
0360   _LIBCPP_HIDE_FROM_ABI static int __fseek(FILE* __file, pos_type __offset, int __whence);
0361   _LIBCPP_HIDE_FROM_ABI static pos_type __ftell(FILE* __file);
0362 
0363   _LIBCPP_EXPORTED_FROM_ABI friend FILE* __get_ostream_file(ostream&);
0364 
0365   // There are multiple (__)open function, they use different C-API open
0366   // function. After that call these functions behave the same. This function
0367   // does that part and determines the final return value.
0368   _LIBCPP_HIDE_FROM_ABI basic_filebuf* __do_open(FILE* __file, ios_base::openmode __mode) {
0369     __file_ = __file;
0370     if (!__file_)
0371       return nullptr;
0372 
0373     __om_ = __mode;
0374     if (__cm_ == (__no_io_operations | __use_unbuffered_io)) {
0375       std::setbuf(__file_, nullptr);
0376       __cm_ = 0;
0377     }
0378 
0379     if (__mode & ios_base::ate) {
0380       __cm_ = 0;
0381       if (fseek(__file_, 0, SEEK_END)) {
0382         fclose(__file_);
0383         __file_ = nullptr;
0384         return nullptr;
0385       }
0386     }
0387 
0388     return this;
0389   }
0390 
0391   // If the file is already open, switch to unbuffered mode. Otherwise, record
0392   // the request to use unbuffered mode so that we use that mode when we
0393   // eventually open the file.
0394   _LIBCPP_HIDE_FROM_ABI void __request_unbuffered_mode(char_type* __s, streamsize __n) {
0395     if (__cm_ == __no_io_operations && __s == nullptr && __n == 0) {
0396       if (__file_) {
0397         std::setbuf(__file_, nullptr);
0398         __cm_ = 0;
0399       } else {
0400         __cm_ = __no_io_operations | __use_unbuffered_io;
0401       }
0402     }
0403   }
0404 };
0405 
0406 template <class _CharT, class _Traits>
0407 basic_filebuf<_CharT, _Traits>::basic_filebuf()
0408     : __extbuf_(nullptr),
0409       __extbufnext_(nullptr),
0410       __extbufend_(nullptr),
0411       __ebs_(0),
0412       __intbuf_(nullptr),
0413       __ibs_(0),
0414       __file_(nullptr),
0415       __cv_(nullptr),
0416       __st_(),
0417       __st_last_(),
0418       __om_(0),
0419       __cm_(__no_io_operations),
0420       __owns_eb_(false),
0421       __owns_ib_(false),
0422       __always_noconv_(false) {
0423   if (std::has_facet<codecvt<char_type, char, state_type> >(this->getloc())) {
0424     __cv_            = &std::use_facet<codecvt<char_type, char, state_type> >(this->getloc());
0425     __always_noconv_ = __cv_->always_noconv();
0426   }
0427   setbuf(nullptr, 4096);
0428 }
0429 
0430 template <class _CharT, class _Traits>
0431 basic_filebuf<_CharT, _Traits>::basic_filebuf(basic_filebuf&& __rhs) : basic_streambuf<_CharT, _Traits>(__rhs) {
0432   if (__rhs.__extbuf_ == __rhs.__extbuf_min_) {
0433     __extbuf_     = __extbuf_min_;
0434     __extbufnext_ = __extbuf_ + (__rhs.__extbufnext_ - __rhs.__extbuf_);
0435     __extbufend_  = __extbuf_ + (__rhs.__extbufend_ - __rhs.__extbuf_);
0436   } else {
0437     __extbuf_     = __rhs.__extbuf_;
0438     __extbufnext_ = __rhs.__extbufnext_;
0439     __extbufend_  = __rhs.__extbufend_;
0440   }
0441   __ebs_           = __rhs.__ebs_;
0442   __intbuf_        = __rhs.__intbuf_;
0443   __ibs_           = __rhs.__ibs_;
0444   __file_          = __rhs.__file_;
0445   __cv_            = __rhs.__cv_;
0446   __st_            = __rhs.__st_;
0447   __st_last_       = __rhs.__st_last_;
0448   __om_            = __rhs.__om_;
0449   __cm_            = __rhs.__cm_;
0450   __owns_eb_       = __rhs.__owns_eb_;
0451   __owns_ib_       = __rhs.__owns_ib_;
0452   __always_noconv_ = __rhs.__always_noconv_;
0453   if (__rhs.pbase()) {
0454     if (__rhs.pbase() == __rhs.__intbuf_)
0455       this->setp(__intbuf_, __intbuf_ + (__rhs.epptr() - __rhs.pbase()));
0456     else
0457       this->setp((char_type*)__extbuf_, (char_type*)__extbuf_ + (__rhs.epptr() - __rhs.pbase()));
0458     this->__pbump(__rhs.pptr() - __rhs.pbase());
0459   } else if (__rhs.eback()) {
0460     if (__rhs.eback() == __rhs.__intbuf_)
0461       this->setg(__intbuf_, __intbuf_ + (__rhs.gptr() - __rhs.eback()), __intbuf_ + (__rhs.egptr() - __rhs.eback()));
0462     else
0463       this->setg((char_type*)__extbuf_,
0464                  (char_type*)__extbuf_ + (__rhs.gptr() - __rhs.eback()),
0465                  (char_type*)__extbuf_ + (__rhs.egptr() - __rhs.eback()));
0466   }
0467   __rhs.__extbuf_     = nullptr;
0468   __rhs.__extbufnext_ = nullptr;
0469   __rhs.__extbufend_  = nullptr;
0470   __rhs.__ebs_        = 0;
0471   __rhs.__intbuf_     = 0;
0472   __rhs.__ibs_        = 0;
0473   __rhs.__file_       = nullptr;
0474   __rhs.__st_         = state_type();
0475   __rhs.__st_last_    = state_type();
0476   __rhs.__om_         = 0;
0477   __rhs.__cm_         = 0;
0478   __rhs.__owns_eb_    = false;
0479   __rhs.__owns_ib_    = false;
0480   __rhs.setg(0, 0, 0);
0481   __rhs.setp(0, 0);
0482 }
0483 
0484 template <class _CharT, class _Traits>
0485 inline basic_filebuf<_CharT, _Traits>& basic_filebuf<_CharT, _Traits>::operator=(basic_filebuf&& __rhs) {
0486   close();
0487   swap(__rhs);
0488   return *this;
0489 }
0490 
0491 template <class _CharT, class _Traits>
0492 basic_filebuf<_CharT, _Traits>::~basic_filebuf() {
0493 #    if _LIBCPP_HAS_EXCEPTIONS
0494   try {
0495 #    endif // _LIBCPP_HAS_EXCEPTIONS
0496     close();
0497 #    if _LIBCPP_HAS_EXCEPTIONS
0498   } catch (...) {
0499   }
0500 #    endif // _LIBCPP_HAS_EXCEPTIONS
0501   if (__owns_eb_)
0502     delete[] __extbuf_;
0503   if (__owns_ib_)
0504     delete[] __intbuf_;
0505 }
0506 
0507 template <class _CharT, class _Traits>
0508 void basic_filebuf<_CharT, _Traits>::swap(basic_filebuf& __rhs) {
0509   basic_streambuf<char_type, traits_type>::swap(__rhs);
0510   if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_) {
0511     // Neither *this nor __rhs uses the small buffer, so we can simply swap the pointers.
0512     std::swap(__extbuf_, __rhs.__extbuf_);
0513     std::swap(__extbufnext_, __rhs.__extbufnext_);
0514     std::swap(__extbufend_, __rhs.__extbufend_);
0515   } else {
0516     ptrdiff_t __ln = __extbufnext_ ? __extbufnext_ - __extbuf_ : 0;
0517     ptrdiff_t __le = __extbufend_ ? __extbufend_ - __extbuf_ : 0;
0518     ptrdiff_t __rn = __rhs.__extbufnext_ ? __rhs.__extbufnext_ - __rhs.__extbuf_ : 0;
0519     ptrdiff_t __re = __rhs.__extbufend_ ? __rhs.__extbufend_ - __rhs.__extbuf_ : 0;
0520     if (__extbuf_ == __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_) {
0521       // *this uses the small buffer, but __rhs doesn't.
0522       __extbuf_       = __rhs.__extbuf_;
0523       __rhs.__extbuf_ = __rhs.__extbuf_min_;
0524       std::memmove(__rhs.__extbuf_min_, __extbuf_min_, sizeof(__extbuf_min_));
0525     } else if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ == __rhs.__extbuf_min_) {
0526       // *this doesn't use the small buffer, but __rhs does.
0527       __rhs.__extbuf_ = __extbuf_;
0528       __extbuf_       = __extbuf_min_;
0529       std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));
0530     } else {
0531       // Both *this and __rhs use the small buffer.
0532       char __tmp[sizeof(__extbuf_min_)];
0533       std::memmove(__tmp, __extbuf_min_, sizeof(__extbuf_min_));
0534       std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));
0535       std::memmove(__rhs.__extbuf_min_, __tmp, sizeof(__extbuf_min_));
0536     }
0537     __extbufnext_       = __extbuf_ + __rn;
0538     __extbufend_        = __extbuf_ + __re;
0539     __rhs.__extbufnext_ = __rhs.__extbuf_ + __ln;
0540     __rhs.__extbufend_  = __rhs.__extbuf_ + __le;
0541   }
0542   std::swap(__ebs_, __rhs.__ebs_);
0543   std::swap(__intbuf_, __rhs.__intbuf_);
0544   std::swap(__ibs_, __rhs.__ibs_);
0545   std::swap(__file_, __rhs.__file_);
0546   std::swap(__cv_, __rhs.__cv_);
0547   std::swap(__st_, __rhs.__st_);
0548   std::swap(__st_last_, __rhs.__st_last_);
0549   std::swap(__om_, __rhs.__om_);
0550   std::swap(__cm_, __rhs.__cm_);
0551   std::swap(__owns_eb_, __rhs.__owns_eb_);
0552   std::swap(__owns_ib_, __rhs.__owns_ib_);
0553   std::swap(__always_noconv_, __rhs.__always_noconv_);
0554   if (this->eback() == (char_type*)__rhs.__extbuf_min_) {
0555     ptrdiff_t __n = this->gptr() - this->eback();
0556     ptrdiff_t __e = this->egptr() - this->eback();
0557     this->setg((char_type*)__extbuf_min_, (char_type*)__extbuf_min_ + __n, (char_type*)__extbuf_min_ + __e);
0558   } else if (this->pbase() == (char_type*)__rhs.__extbuf_min_) {
0559     ptrdiff_t __n = this->pptr() - this->pbase();
0560     ptrdiff_t __e = this->epptr() - this->pbase();
0561     this->setp((char_type*)__extbuf_min_, (char_type*)__extbuf_min_ + __e);
0562     this->__pbump(__n);
0563   }
0564   if (__rhs.eback() == (char_type*)__extbuf_min_) {
0565     ptrdiff_t __n = __rhs.gptr() - __rhs.eback();
0566     ptrdiff_t __e = __rhs.egptr() - __rhs.eback();
0567     __rhs.setg(
0568         (char_type*)__rhs.__extbuf_min_, (char_type*)__rhs.__extbuf_min_ + __n, (char_type*)__rhs.__extbuf_min_ + __e);
0569   } else if (__rhs.pbase() == (char_type*)__extbuf_min_) {
0570     ptrdiff_t __n = __rhs.pptr() - __rhs.pbase();
0571     ptrdiff_t __e = __rhs.epptr() - __rhs.pbase();
0572     __rhs.setp((char_type*)__rhs.__extbuf_min_, (char_type*)__rhs.__extbuf_min_ + __e);
0573     __rhs.__pbump(__n);
0574   }
0575 }
0576 
0577 template <class _CharT, class _Traits>
0578 inline _LIBCPP_HIDE_FROM_ABI void swap(basic_filebuf<_CharT, _Traits>& __x, basic_filebuf<_CharT, _Traits>& __y) {
0579   __x.swap(__y);
0580 }
0581 
0582 template <class _CharT, class _Traits>
0583 inline bool basic_filebuf<_CharT, _Traits>::is_open() const {
0584   return __file_ != nullptr;
0585 }
0586 
0587 template <class _CharT, class _Traits>
0588 const char* basic_filebuf<_CharT, _Traits>::__make_mdstring(ios_base::openmode __mode) _NOEXCEPT {
0589   switch (__mode & ~ios_base::ate) {
0590   case ios_base::out:
0591   case ios_base::out | ios_base::trunc:
0592     return "w" _LIBCPP_FOPEN_CLOEXEC_MODE;
0593   case ios_base::out | ios_base::app:
0594   case ios_base::app:
0595     return "a" _LIBCPP_FOPEN_CLOEXEC_MODE;
0596   case ios_base::in:
0597     return "r" _LIBCPP_FOPEN_CLOEXEC_MODE;
0598   case ios_base::in | ios_base::out:
0599     return "r+" _LIBCPP_FOPEN_CLOEXEC_MODE;
0600   case ios_base::in | ios_base::out | ios_base::trunc:
0601     return "w+" _LIBCPP_FOPEN_CLOEXEC_MODE;
0602   case ios_base::in | ios_base::out | ios_base::app:
0603   case ios_base::in | ios_base::app:
0604     return "a+" _LIBCPP_FOPEN_CLOEXEC_MODE;
0605   case ios_base::out | ios_base::binary:
0606   case ios_base::out | ios_base::trunc | ios_base::binary:
0607     return "wb" _LIBCPP_FOPEN_CLOEXEC_MODE;
0608   case ios_base::out | ios_base::app | ios_base::binary:
0609   case ios_base::app | ios_base::binary:
0610     return "ab" _LIBCPP_FOPEN_CLOEXEC_MODE;
0611   case ios_base::in | ios_base::binary:
0612     return "rb" _LIBCPP_FOPEN_CLOEXEC_MODE;
0613   case ios_base::in | ios_base::out | ios_base::binary:
0614     return "r+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
0615   case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
0616     return "w+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
0617   case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
0618   case ios_base::in | ios_base::app | ios_base::binary:
0619     return "a+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
0620 #    if _LIBCPP_STD_VER >= 23
0621   case ios_base::out | ios_base::noreplace:
0622   case ios_base::out | ios_base::trunc | ios_base::noreplace:
0623     return "wx" _LIBCPP_FOPEN_CLOEXEC_MODE;
0624   case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:
0625     return "w+x" _LIBCPP_FOPEN_CLOEXEC_MODE;
0626   case ios_base::out | ios_base::binary | ios_base::noreplace:
0627   case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
0628     return "wbx" _LIBCPP_FOPEN_CLOEXEC_MODE;
0629   case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
0630     return "w+bx" _LIBCPP_FOPEN_CLOEXEC_MODE;
0631 #    endif // _LIBCPP_STD_VER >= 23
0632   default:
0633     return nullptr;
0634   }
0635   __libcpp_unreachable();
0636 }
0637 
0638 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
0639 template <class _CharT, class _Traits>
0640 const wchar_t* basic_filebuf<_CharT, _Traits>::__make_mdwstring(ios_base::openmode __mode) _NOEXCEPT {
0641   switch (__mode & ~ios_base::ate) {
0642   case ios_base::out:
0643   case ios_base::out | ios_base::trunc:
0644     return L"w";
0645   case ios_base::out | ios_base::app:
0646   case ios_base::app:
0647     return L"a";
0648   case ios_base::in:
0649     return L"r";
0650   case ios_base::in | ios_base::out:
0651     return L"r+";
0652   case ios_base::in | ios_base::out | ios_base::trunc:
0653     return L"w+";
0654   case ios_base::in | ios_base::out | ios_base::app:
0655   case ios_base::in | ios_base::app:
0656     return L"a+";
0657   case ios_base::out | ios_base::binary:
0658   case ios_base::out | ios_base::trunc | ios_base::binary:
0659     return L"wb";
0660   case ios_base::out | ios_base::app | ios_base::binary:
0661   case ios_base::app | ios_base::binary:
0662     return L"ab";
0663   case ios_base::in | ios_base::binary:
0664     return L"rb";
0665   case ios_base::in | ios_base::out | ios_base::binary:
0666     return L"r+b";
0667   case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
0668     return L"w+b";
0669   case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
0670   case ios_base::in | ios_base::app | ios_base::binary:
0671     return L"a+b";
0672 #      if _LIBCPP_STD_VER >= 23
0673   case ios_base::out | ios_base::noreplace:
0674   case ios_base::out | ios_base::trunc | ios_base::noreplace:
0675     return L"wx";
0676   case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:
0677     return L"w+x";
0678   case ios_base::out | ios_base::binary | ios_base::noreplace:
0679   case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
0680     return L"wbx";
0681   case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
0682     return L"w+bx";
0683 #      endif // _LIBCPP_STD_VER >= 23
0684   default:
0685     return nullptr;
0686   }
0687   __libcpp_unreachable();
0688 }
0689 #    endif
0690 
0691 template <class _CharT, class _Traits>
0692 basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
0693   if (__file_)
0694     return nullptr;
0695   const char* __mdstr = __make_mdstring(__mode);
0696   if (!__mdstr)
0697     return nullptr;
0698 
0699   return __do_open(fopen(__s, __mdstr), __mode);
0700 }
0701 
0702 template <class _CharT, class _Traits>
0703 inline basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
0704   if (__file_)
0705     return nullptr;
0706   const char* __mdstr = __make_mdstring(__mode);
0707   if (!__mdstr)
0708     return nullptr;
0709 
0710   return __do_open(fdopen(__fd, __mdstr), __mode);
0711 }
0712 
0713 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
0714 // This is basically the same as the char* overload except that it uses _wfopen
0715 // and long mode strings.
0716 template <class _CharT, class _Traits>
0717 basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {
0718   if (__file_)
0719     return nullptr;
0720   const wchar_t* __mdstr = __make_mdwstring(__mode);
0721   if (!__mdstr)
0722     return nullptr;
0723 
0724   return __do_open(_wfopen(__s, __mdstr), __mode);
0725 }
0726 #    endif
0727 
0728 template <class _CharT, class _Traits>
0729 inline basic_filebuf<_CharT, _Traits>*
0730 basic_filebuf<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {
0731   return open(__s.c_str(), __mode);
0732 }
0733 
0734 template <class _CharT, class _Traits>
0735 basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::close() {
0736   basic_filebuf<_CharT, _Traits>* __rt = nullptr;
0737   if (__file_) {
0738     __rt = this;
0739     unique_ptr<FILE, int (*)(FILE*)> __h(__file_, fclose);
0740     if (sync())
0741       __rt = nullptr;
0742     if (fclose(__h.release()))
0743       __rt = nullptr;
0744     __file_ = nullptr;
0745     setbuf(0, 0);
0746   }
0747   return __rt;
0748 }
0749 
0750 template <class _CharT, class _Traits>
0751 typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::underflow() {
0752   if (__file_ == nullptr)
0753     return traits_type::eof();
0754   bool __initial = __read_mode();
0755   char_type __1buf;
0756   if (this->gptr() == nullptr)
0757     this->setg(&__1buf, &__1buf + 1, &__1buf + 1);
0758   const size_t __unget_sz = __initial ? 0 : std::min<size_t>((this->egptr() - this->eback()) / 2, 4);
0759   int_type __c            = traits_type::eof();
0760   if (this->gptr() == this->egptr()) {
0761     std::memmove(this->eback(), this->egptr() - __unget_sz, __unget_sz * sizeof(char_type));
0762     if (__always_noconv_) {
0763       size_t __nmemb = static_cast<size_t>(this->egptr() - this->eback() - __unget_sz);
0764       __nmemb        = ::fread(this->eback() + __unget_sz, 1, __nmemb, __file_);
0765       if (__nmemb != 0) {
0766         this->setg(this->eback(), this->eback() + __unget_sz, this->eback() + __unget_sz + __nmemb);
0767         __c = traits_type::to_int_type(*this->gptr());
0768       }
0769     } else {
0770       if (__extbufend_ != __extbufnext_) {
0771         _LIBCPP_ASSERT_NON_NULL(__extbufnext_ != nullptr, "underflow moving from nullptr");
0772         _LIBCPP_ASSERT_NON_NULL(__extbuf_ != nullptr, "underflow moving into nullptr");
0773         std::memmove(__extbuf_, __extbufnext_, __extbufend_ - __extbufnext_);
0774       }
0775       __extbufnext_ = __extbuf_ + (__extbufend_ - __extbufnext_);
0776       __extbufend_  = __extbuf_ + (__extbuf_ == __extbuf_min_ ? sizeof(__extbuf_min_) : __ebs_);
0777       size_t __nmemb =
0778           std::min(static_cast<size_t>(__ibs_ - __unget_sz), static_cast<size_t>(__extbufend_ - __extbufnext_));
0779       codecvt_base::result __r;
0780       __st_last_  = __st_;
0781       size_t __nr = fread((void*)const_cast<char*>(__extbufnext_), 1, __nmemb, __file_);
0782       if (__nr != 0) {
0783         if (!__cv_)
0784           __throw_bad_cast();
0785 
0786         __extbufend_ = __extbufnext_ + __nr;
0787         char_type* __inext;
0788         __r = __cv_->in(
0789             __st_, __extbuf_, __extbufend_, __extbufnext_, this->eback() + __unget_sz, this->eback() + __ibs_, __inext);
0790         if (__r == codecvt_base::noconv) {
0791           this->setg((char_type*)__extbuf_, (char_type*)__extbuf_, (char_type*)const_cast<char*>(__extbufend_));
0792           __c = traits_type::to_int_type(*this->gptr());
0793         } else if (__inext != this->eback() + __unget_sz) {
0794           this->setg(this->eback(), this->eback() + __unget_sz, __inext);
0795           __c = traits_type::to_int_type(*this->gptr());
0796         }
0797       }
0798     }
0799   } else
0800     __c = traits_type::to_int_type(*this->gptr());
0801   if (this->eback() == &__1buf)
0802     this->setg(nullptr, nullptr, nullptr);
0803   return __c;
0804 }
0805 
0806 template <class _CharT, class _Traits>
0807 typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::pbackfail(int_type __c) {
0808   if (__file_ && this->eback() < this->gptr()) {
0809     if (traits_type::eq_int_type(__c, traits_type::eof())) {
0810       this->gbump(-1);
0811       return traits_type::not_eof(__c);
0812     }
0813     if ((__om_ & ios_base::out) || traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1])) {
0814       this->gbump(-1);
0815       *this->gptr() = traits_type::to_char_type(__c);
0816       return __c;
0817     }
0818   }
0819   return traits_type::eof();
0820 }
0821 
0822 template <class _CharT, class _Traits>
0823 typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::overflow(int_type __c) {
0824   if (__file_ == nullptr)
0825     return traits_type::eof();
0826   __write_mode();
0827   char_type __1buf;
0828   char_type* __pb_save  = this->pbase();
0829   char_type* __epb_save = this->epptr();
0830   if (!traits_type::eq_int_type(__c, traits_type::eof())) {
0831     if (this->pptr() == nullptr)
0832       this->setp(&__1buf, &__1buf + 1);
0833     *this->pptr() = traits_type::to_char_type(__c);
0834     this->pbump(1);
0835   }
0836   if (this->pptr() != this->pbase()) {
0837     if (__always_noconv_) {
0838       size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
0839       if (std::fwrite(this->pbase(), sizeof(char_type), __nmemb, __file_) != __nmemb)
0840         return traits_type::eof();
0841     } else {
0842       char* __extbe = __extbuf_;
0843       codecvt_base::result __r;
0844       do {
0845         if (!__cv_)
0846           __throw_bad_cast();
0847 
0848         const char_type* __e;
0849         __r = __cv_->out(__st_, this->pbase(), this->pptr(), __e, __extbuf_, __extbuf_ + __ebs_, __extbe);
0850         if (__e == this->pbase())
0851           return traits_type::eof();
0852         if (__r == codecvt_base::noconv) {
0853           size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
0854           if (std::fwrite(this->pbase(), 1, __nmemb, __file_) != __nmemb)
0855             return traits_type::eof();
0856         } else if (__r == codecvt_base::ok || __r == codecvt_base::partial) {
0857           size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
0858           if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
0859             return traits_type::eof();
0860           if (__r == codecvt_base::partial) {
0861             this->setp(const_cast<char_type*>(__e), this->pptr());
0862             this->__pbump(this->epptr() - this->pbase());
0863           }
0864         } else
0865           return traits_type::eof();
0866       } while (__r == codecvt_base::partial);
0867     }
0868     this->setp(__pb_save, __epb_save);
0869   }
0870   return traits_type::not_eof(__c);
0871 }
0872 
0873 template <class _CharT, class _Traits>
0874 basic_streambuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::setbuf(char_type* __s, streamsize __n) {
0875   this->setg(nullptr, nullptr, nullptr);
0876   this->setp(nullptr, nullptr);
0877   __request_unbuffered_mode(__s, __n);
0878   if (__owns_eb_)
0879     delete[] __extbuf_;
0880   if (__owns_ib_)
0881     delete[] __intbuf_;
0882   __ebs_ = __n;
0883   if (__ebs_ > sizeof(__extbuf_min_)) {
0884     if (__always_noconv_ && __s) {
0885       __extbuf_  = (char*)__s;
0886       __owns_eb_ = false;
0887     } else {
0888       __extbuf_  = new char[__ebs_];
0889       __owns_eb_ = true;
0890     }
0891   } else {
0892     __extbuf_  = __extbuf_min_;
0893     __ebs_     = sizeof(__extbuf_min_);
0894     __owns_eb_ = false;
0895   }
0896   if (!__always_noconv_) {
0897     __ibs_ = max<streamsize>(__n, sizeof(__extbuf_min_));
0898     if (__s && __ibs_ > sizeof(__extbuf_min_)) {
0899       __intbuf_  = __s;
0900       __owns_ib_ = false;
0901     } else {
0902       __intbuf_  = new char_type[__ibs_];
0903       __owns_ib_ = true;
0904     }
0905   } else {
0906     __ibs_     = 0;
0907     __intbuf_  = nullptr;
0908     __owns_ib_ = false;
0909   }
0910   return this;
0911 }
0912 
0913 template <class _CharT, class _Traits>
0914 typename basic_filebuf<_CharT, _Traits>::pos_type
0915 basic_filebuf<_CharT, _Traits>::seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode) {
0916   if (!__cv_)
0917     __throw_bad_cast();
0918 
0919   int __width = __cv_->encoding();
0920   if (__file_ == nullptr || (__width <= 0 && __off != 0) || sync())
0921     return pos_type(off_type(-1));
0922   // __width > 0 || __off == 0
0923   int __whence;
0924   switch (__way) {
0925   case ios_base::beg:
0926     __whence = SEEK_SET;
0927     break;
0928   case ios_base::cur:
0929     __whence = SEEK_CUR;
0930     break;
0931   case ios_base::end:
0932     __whence = SEEK_END;
0933     break;
0934   default:
0935     return pos_type(off_type(-1));
0936   }
0937   if (__fseek(__file_, __width > 0 ? __width * __off : 0, __whence))
0938     return pos_type(off_type(-1));
0939   pos_type __r = __ftell(__file_);
0940   __r.state(__st_);
0941   return __r;
0942 }
0943 
0944 template <class _CharT, class _Traits>
0945 int basic_filebuf<_CharT, _Traits>::__fseek(FILE* __file, pos_type __offset, int __whence) {
0946 #    if defined(_LIBCPP_MSVCRT_LIKE)
0947   return _fseeki64(__file, __offset, __whence);
0948 #    elif defined(_NEWLIB_VERSION)
0949   return fseek(__file, __offset, __whence);
0950 #    else
0951   return ::fseeko(__file, __offset, __whence);
0952 #    endif
0953 }
0954 
0955 template <class _CharT, class _Traits>
0956 typename basic_filebuf<_CharT, _Traits>::pos_type basic_filebuf<_CharT, _Traits>::__ftell(FILE* __file) {
0957 #    if defined(_LIBCPP_MSVCRT_LIKE)
0958   return _ftelli64(__file);
0959 #    elif defined(_NEWLIB_VERSION)
0960   return ftell(__file);
0961 #    else
0962   return ftello(__file);
0963 #    endif
0964 }
0965 
0966 template <class _CharT, class _Traits>
0967 typename basic_filebuf<_CharT, _Traits>::pos_type
0968 basic_filebuf<_CharT, _Traits>::seekpos(pos_type __sp, ios_base::openmode) {
0969   if (__file_ == nullptr || sync())
0970     return pos_type(off_type(-1));
0971   if (__fseek(__file_, __sp, SEEK_SET))
0972     return pos_type(off_type(-1));
0973   __st_ = __sp.state();
0974   return __sp;
0975 }
0976 
0977 template <class _CharT, class _Traits>
0978 int basic_filebuf<_CharT, _Traits>::sync() {
0979   if (__file_ == nullptr)
0980     return 0;
0981   if (!__cv_)
0982     __throw_bad_cast();
0983 
0984   if (__cm_ & ios_base::out) {
0985     if (this->pptr() != this->pbase())
0986       if (overflow() == traits_type::eof())
0987         return -1;
0988     codecvt_base::result __r;
0989     do {
0990       char* __extbe;
0991       __r            = __cv_->unshift(__st_, __extbuf_, __extbuf_ + __ebs_, __extbe);
0992       size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
0993       if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
0994         return -1;
0995     } while (__r == codecvt_base::partial);
0996     if (__r == codecvt_base::error)
0997       return -1;
0998     if (fflush(__file_))
0999       return -1;
1000   } else if (__cm_ & ios_base::in) {
1001     off_type __c;
1002     state_type __state = __st_last_;
1003     bool __update_st   = false;
1004     if (__always_noconv_)
1005       __c = this->egptr() - this->gptr();
1006     else {
1007       int __width = __cv_->encoding();
1008       __c         = __extbufend_ - __extbufnext_;
1009       if (__width > 0)
1010         __c += __width * (this->egptr() - this->gptr());
1011       else {
1012         if (this->gptr() != this->egptr()) {
1013           const int __off = __cv_->length(__state, __extbuf_, __extbufnext_, this->gptr() - this->eback());
1014           __c += __extbufnext_ - __extbuf_ - __off;
1015           __update_st = true;
1016         }
1017       }
1018     }
1019     if (__fseek(__file_, -__c, SEEK_CUR))
1020       return -1;
1021     if (__update_st)
1022       __st_ = __state;
1023     __extbufnext_ = __extbufend_ = __extbuf_;
1024     this->setg(nullptr, nullptr, nullptr);
1025     __cm_ = 0;
1026   }
1027   return 0;
1028 }
1029 
1030 template <class _CharT, class _Traits>
1031 void basic_filebuf<_CharT, _Traits>::imbue(const locale& __loc) {
1032   sync();
1033   __cv_            = &std::use_facet<codecvt<char_type, char, state_type> >(__loc);
1034   bool __old_anc   = __always_noconv_;
1035   __always_noconv_ = __cv_->always_noconv();
1036   if (__old_anc != __always_noconv_) {
1037     this->setg(nullptr, nullptr, nullptr);
1038     this->setp(nullptr, nullptr);
1039     // invariant, char_type is char, else we couldn't get here
1040     if (__always_noconv_) // need to dump __intbuf_
1041     {
1042       if (__owns_eb_)
1043         delete[] __extbuf_;
1044       __owns_eb_ = __owns_ib_;
1045       __ebs_     = __ibs_;
1046       __extbuf_  = (char*)__intbuf_;
1047       __ibs_     = 0;
1048       __intbuf_  = nullptr;
1049       __owns_ib_ = false;
1050     } else // need to obtain an __intbuf_.
1051     {      // If __extbuf_ is user-supplied, use it, else new __intbuf_
1052       if (!__owns_eb_ && __extbuf_ != __extbuf_min_) {
1053         __ibs_     = __ebs_;
1054         __intbuf_  = (char_type*)__extbuf_;
1055         __owns_ib_ = false;
1056         __extbuf_  = new char[__ebs_];
1057         __owns_eb_ = true;
1058       } else {
1059         __ibs_     = __ebs_;
1060         __intbuf_  = new char_type[__ibs_];
1061         __owns_ib_ = true;
1062       }
1063     }
1064   }
1065 }
1066 
1067 template <class _CharT, class _Traits>
1068 bool basic_filebuf<_CharT, _Traits>::__read_mode() {
1069   if (!(__cm_ & ios_base::in)) {
1070     this->setp(nullptr, nullptr);
1071     if (__always_noconv_)
1072       this->setg((char_type*)__extbuf_, (char_type*)__extbuf_ + __ebs_, (char_type*)__extbuf_ + __ebs_);
1073     else
1074       this->setg(__intbuf_, __intbuf_ + __ibs_, __intbuf_ + __ibs_);
1075     __cm_ = ios_base::in;
1076     return true;
1077   }
1078   return false;
1079 }
1080 
1081 template <class _CharT, class _Traits>
1082 void basic_filebuf<_CharT, _Traits>::__write_mode() {
1083   if (!(__cm_ & ios_base::out)) {
1084     this->setg(nullptr, nullptr, nullptr);
1085     if (__ebs_ > sizeof(__extbuf_min_)) {
1086       if (__always_noconv_)
1087         this->setp((char_type*)__extbuf_, (char_type*)__extbuf_ + (__ebs_ - 1));
1088       else
1089         this->setp(__intbuf_, __intbuf_ + (__ibs_ - 1));
1090     } else
1091       this->setp(nullptr, nullptr);
1092     __cm_ = ios_base::out;
1093   }
1094 }
1095 
1096 // basic_ifstream
1097 
1098 template <class _CharT, class _Traits>
1099 class _LIBCPP_TEMPLATE_VIS basic_ifstream : public basic_istream<_CharT, _Traits> {
1100 public:
1101   typedef _CharT char_type;
1102   typedef _Traits traits_type;
1103   typedef typename traits_type::int_type int_type;
1104   typedef typename traits_type::pos_type pos_type;
1105   typedef typename traits_type::off_type off_type;
1106 #    if _LIBCPP_STD_VER >= 26
1107   using native_handle_type = typename basic_filebuf<_CharT, _Traits>::native_handle_type;
1108 #    endif
1109 
1110   _LIBCPP_HIDE_FROM_ABI basic_ifstream();
1111   _LIBCPP_HIDE_FROM_ABI explicit basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in);
1112 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1113   _LIBCPP_HIDE_FROM_ABI explicit basic_ifstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
1114 #    endif
1115   _LIBCPP_HIDE_FROM_ABI explicit basic_ifstream(const string& __s, ios_base::openmode __mode = ios_base::in);
1116 #    if _LIBCPP_STD_VER >= 17
1117   template <class _Tp, class = enable_if_t<is_same_v<_Tp, filesystem::path>>>
1118   _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY
1119       _LIBCPP_HIDE_FROM_ABI explicit basic_ifstream(const _Tp& __p, ios_base::openmode __mode = ios_base::in)
1120       : basic_ifstream(__p.c_str(), __mode) {}
1121 #    endif // _LIBCPP_STD_VER >= 17
1122   _LIBCPP_HIDE_FROM_ABI basic_ifstream(basic_ifstream&& __rhs);
1123   _LIBCPP_HIDE_FROM_ABI basic_ifstream& operator=(basic_ifstream&& __rhs);
1124   _LIBCPP_HIDE_FROM_ABI void swap(basic_ifstream& __rhs);
1125 
1126   _LIBCPP_HIDE_FROM_ABI basic_filebuf<char_type, traits_type>* rdbuf() const;
1127 #    if _LIBCPP_STD_VER >= 26
1128   _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() const noexcept { return rdbuf()->native_handle(); }
1129 #    endif
1130   _LIBCPP_HIDE_FROM_ABI bool is_open() const;
1131   void open(const char* __s, ios_base::openmode __mode = ios_base::in);
1132 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1133   void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
1134 #    endif
1135   void open(const string& __s, ios_base::openmode __mode = ios_base::in);
1136 #    if _LIBCPP_STD_VER >= 17
1137   _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI void
1138   open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in) {
1139     return open(__p.c_str(), __mode);
1140   }
1141 #    endif // _LIBCPP_STD_VER >= 17
1142 
1143   _LIBCPP_HIDE_FROM_ABI void __open(int __fd, ios_base::openmode __mode);
1144   _LIBCPP_HIDE_FROM_ABI void close();
1145 
1146 private:
1147   basic_filebuf<char_type, traits_type> __sb_;
1148 };
1149 
1150 template <class _CharT, class _Traits>
1151 inline basic_ifstream<_CharT, _Traits>::basic_ifstream()
1152     : basic_istream<char_type, traits_type>(std::addressof(__sb_)) {}
1153 
1154 template <class _CharT, class _Traits>
1155 inline basic_ifstream<_CharT, _Traits>::basic_ifstream(const char* __s, ios_base::openmode __mode)
1156     : basic_istream<char_type, traits_type>(std::addressof(__sb_)) {
1157   if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1158     this->setstate(ios_base::failbit);
1159 }
1160 
1161 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1162 template <class _CharT, class _Traits>
1163 inline basic_ifstream<_CharT, _Traits>::basic_ifstream(const wchar_t* __s, ios_base::openmode __mode)
1164     : basic_istream<char_type, traits_type>(std::addressof(__sb_)) {
1165   if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1166     this->setstate(ios_base::failbit);
1167 }
1168 #    endif
1169 
1170 // extension
1171 template <class _CharT, class _Traits>
1172 inline basic_ifstream<_CharT, _Traits>::basic_ifstream(const string& __s, ios_base::openmode __mode)
1173     : basic_istream<char_type, traits_type>(std::addressof(__sb_)) {
1174   if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1175     this->setstate(ios_base::failbit);
1176 }
1177 
1178 template <class _CharT, class _Traits>
1179 inline basic_ifstream<_CharT, _Traits>::basic_ifstream(basic_ifstream&& __rhs)
1180     : basic_istream<char_type, traits_type>(std::move(__rhs)), __sb_(std::move(__rhs.__sb_)) {
1181   this->set_rdbuf(std::addressof(__sb_));
1182 }
1183 
1184 template <class _CharT, class _Traits>
1185 inline basic_ifstream<_CharT, _Traits>& basic_ifstream<_CharT, _Traits>::operator=(basic_ifstream&& __rhs) {
1186   basic_istream<char_type, traits_type>::operator=(std::move(__rhs));
1187   __sb_ = std::move(__rhs.__sb_);
1188   return *this;
1189 }
1190 
1191 template <class _CharT, class _Traits>
1192 inline void basic_ifstream<_CharT, _Traits>::swap(basic_ifstream& __rhs) {
1193   basic_istream<char_type, traits_type>::swap(__rhs);
1194   __sb_.swap(__rhs.__sb_);
1195 }
1196 
1197 template <class _CharT, class _Traits>
1198 inline _LIBCPP_HIDE_FROM_ABI void swap(basic_ifstream<_CharT, _Traits>& __x, basic_ifstream<_CharT, _Traits>& __y) {
1199   __x.swap(__y);
1200 }
1201 
1202 template <class _CharT, class _Traits>
1203 inline basic_filebuf<_CharT, _Traits>* basic_ifstream<_CharT, _Traits>::rdbuf() const {
1204   return const_cast<basic_filebuf<char_type, traits_type>*>(std::addressof(__sb_));
1205 }
1206 
1207 template <class _CharT, class _Traits>
1208 inline bool basic_ifstream<_CharT, _Traits>::is_open() const {
1209   return __sb_.is_open();
1210 }
1211 
1212 template <class _CharT, class _Traits>
1213 void basic_ifstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
1214   if (__sb_.open(__s, __mode | ios_base::in))
1215     this->clear();
1216   else
1217     this->setstate(ios_base::failbit);
1218 }
1219 
1220 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1221 template <class _CharT, class _Traits>
1222 void basic_ifstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {
1223   if (__sb_.open(__s, __mode | ios_base::in))
1224     this->clear();
1225   else
1226     this->setstate(ios_base::failbit);
1227 }
1228 #    endif
1229 
1230 template <class _CharT, class _Traits>
1231 void basic_ifstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {
1232   if (__sb_.open(__s, __mode | ios_base::in))
1233     this->clear();
1234   else
1235     this->setstate(ios_base::failbit);
1236 }
1237 
1238 template <class _CharT, class _Traits>
1239 inline void basic_ifstream<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
1240   if (__sb_.__open(__fd, __mode | ios_base::in))
1241     this->clear();
1242   else
1243     this->setstate(ios_base::failbit);
1244 }
1245 
1246 template <class _CharT, class _Traits>
1247 inline void basic_ifstream<_CharT, _Traits>::close() {
1248   if (__sb_.close() == 0)
1249     this->setstate(ios_base::failbit);
1250 }
1251 
1252 // basic_ofstream
1253 
1254 template <class _CharT, class _Traits>
1255 class _LIBCPP_TEMPLATE_VIS basic_ofstream : public basic_ostream<_CharT, _Traits> {
1256 public:
1257   typedef _CharT char_type;
1258   typedef _Traits traits_type;
1259   typedef typename traits_type::int_type int_type;
1260   typedef typename traits_type::pos_type pos_type;
1261   typedef typename traits_type::off_type off_type;
1262 #    if _LIBCPP_STD_VER >= 26
1263   using native_handle_type = typename basic_filebuf<_CharT, _Traits>::native_handle_type;
1264 #    endif
1265 
1266   _LIBCPP_HIDE_FROM_ABI basic_ofstream();
1267   _LIBCPP_HIDE_FROM_ABI explicit basic_ofstream(const char* __s, ios_base::openmode __mode = ios_base::out);
1268 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1269   _LIBCPP_HIDE_FROM_ABI explicit basic_ofstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
1270 #    endif
1271   _LIBCPP_HIDE_FROM_ABI explicit basic_ofstream(const string& __s, ios_base::openmode __mode = ios_base::out);
1272 
1273 #    if _LIBCPP_STD_VER >= 17
1274   template <class _Tp, class = enable_if_t<is_same_v<_Tp, filesystem::path>>>
1275   _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY
1276       _LIBCPP_HIDE_FROM_ABI explicit basic_ofstream(const _Tp& __p, ios_base::openmode __mode = ios_base::out)
1277       : basic_ofstream(__p.c_str(), __mode) {}
1278 #    endif // _LIBCPP_STD_VER >= 17
1279 
1280   _LIBCPP_HIDE_FROM_ABI basic_ofstream(basic_ofstream&& __rhs);
1281   _LIBCPP_HIDE_FROM_ABI basic_ofstream& operator=(basic_ofstream&& __rhs);
1282   _LIBCPP_HIDE_FROM_ABI void swap(basic_ofstream& __rhs);
1283 
1284   _LIBCPP_HIDE_FROM_ABI basic_filebuf<char_type, traits_type>* rdbuf() const;
1285 #    if _LIBCPP_STD_VER >= 26
1286   _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() const noexcept { return rdbuf()->native_handle(); }
1287 #    endif
1288   _LIBCPP_HIDE_FROM_ABI bool is_open() const;
1289   void open(const char* __s, ios_base::openmode __mode = ios_base::out);
1290 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1291   void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
1292 #    endif
1293   void open(const string& __s, ios_base::openmode __mode = ios_base::out);
1294 
1295 #    if _LIBCPP_STD_VER >= 17
1296   _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI void
1297   open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::out) {
1298     return open(__p.c_str(), __mode);
1299   }
1300 #    endif // _LIBCPP_STD_VER >= 17
1301 
1302   _LIBCPP_HIDE_FROM_ABI void __open(int __fd, ios_base::openmode __mode);
1303   _LIBCPP_HIDE_FROM_ABI void close();
1304 
1305 private:
1306   basic_filebuf<char_type, traits_type> __sb_;
1307 };
1308 
1309 template <class _CharT, class _Traits>
1310 inline basic_ofstream<_CharT, _Traits>::basic_ofstream()
1311     : basic_ostream<char_type, traits_type>(std::addressof(__sb_)) {}
1312 
1313 template <class _CharT, class _Traits>
1314 inline basic_ofstream<_CharT, _Traits>::basic_ofstream(const char* __s, ios_base::openmode __mode)
1315     : basic_ostream<char_type, traits_type>(std::addressof(__sb_)) {
1316   if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1317     this->setstate(ios_base::failbit);
1318 }
1319 
1320 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1321 template <class _CharT, class _Traits>
1322 inline basic_ofstream<_CharT, _Traits>::basic_ofstream(const wchar_t* __s, ios_base::openmode __mode)
1323     : basic_ostream<char_type, traits_type>(std::addressof(__sb_)) {
1324   if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1325     this->setstate(ios_base::failbit);
1326 }
1327 #    endif
1328 
1329 // extension
1330 template <class _CharT, class _Traits>
1331 inline basic_ofstream<_CharT, _Traits>::basic_ofstream(const string& __s, ios_base::openmode __mode)
1332     : basic_ostream<char_type, traits_type>(std::addressof(__sb_)) {
1333   if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1334     this->setstate(ios_base::failbit);
1335 }
1336 
1337 template <class _CharT, class _Traits>
1338 inline basic_ofstream<_CharT, _Traits>::basic_ofstream(basic_ofstream&& __rhs)
1339     : basic_ostream<char_type, traits_type>(std::move(__rhs)), __sb_(std::move(__rhs.__sb_)) {
1340   this->set_rdbuf(std::addressof(__sb_));
1341 }
1342 
1343 template <class _CharT, class _Traits>
1344 inline basic_ofstream<_CharT, _Traits>& basic_ofstream<_CharT, _Traits>::operator=(basic_ofstream&& __rhs) {
1345   basic_ostream<char_type, traits_type>::operator=(std::move(__rhs));
1346   __sb_ = std::move(__rhs.__sb_);
1347   return *this;
1348 }
1349 
1350 template <class _CharT, class _Traits>
1351 inline void basic_ofstream<_CharT, _Traits>::swap(basic_ofstream& __rhs) {
1352   basic_ostream<char_type, traits_type>::swap(__rhs);
1353   __sb_.swap(__rhs.__sb_);
1354 }
1355 
1356 template <class _CharT, class _Traits>
1357 inline _LIBCPP_HIDE_FROM_ABI void swap(basic_ofstream<_CharT, _Traits>& __x, basic_ofstream<_CharT, _Traits>& __y) {
1358   __x.swap(__y);
1359 }
1360 
1361 template <class _CharT, class _Traits>
1362 inline basic_filebuf<_CharT, _Traits>* basic_ofstream<_CharT, _Traits>::rdbuf() const {
1363   return const_cast<basic_filebuf<char_type, traits_type>*>(std::addressof(__sb_));
1364 }
1365 
1366 template <class _CharT, class _Traits>
1367 inline bool basic_ofstream<_CharT, _Traits>::is_open() const {
1368   return __sb_.is_open();
1369 }
1370 
1371 template <class _CharT, class _Traits>
1372 void basic_ofstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
1373   if (__sb_.open(__s, __mode | ios_base::out))
1374     this->clear();
1375   else
1376     this->setstate(ios_base::failbit);
1377 }
1378 
1379 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1380 template <class _CharT, class _Traits>
1381 void basic_ofstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {
1382   if (__sb_.open(__s, __mode | ios_base::out))
1383     this->clear();
1384   else
1385     this->setstate(ios_base::failbit);
1386 }
1387 #    endif
1388 
1389 template <class _CharT, class _Traits>
1390 void basic_ofstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {
1391   if (__sb_.open(__s, __mode | ios_base::out))
1392     this->clear();
1393   else
1394     this->setstate(ios_base::failbit);
1395 }
1396 
1397 template <class _CharT, class _Traits>
1398 inline void basic_ofstream<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
1399   if (__sb_.__open(__fd, __mode | ios_base::out))
1400     this->clear();
1401   else
1402     this->setstate(ios_base::failbit);
1403 }
1404 
1405 template <class _CharT, class _Traits>
1406 inline void basic_ofstream<_CharT, _Traits>::close() {
1407   if (__sb_.close() == nullptr)
1408     this->setstate(ios_base::failbit);
1409 }
1410 
1411 // basic_fstream
1412 
1413 template <class _CharT, class _Traits>
1414 class _LIBCPP_TEMPLATE_VIS basic_fstream : public basic_iostream<_CharT, _Traits> {
1415 public:
1416   typedef _CharT char_type;
1417   typedef _Traits traits_type;
1418   typedef typename traits_type::int_type int_type;
1419   typedef typename traits_type::pos_type pos_type;
1420   typedef typename traits_type::off_type off_type;
1421 #    if _LIBCPP_STD_VER >= 26
1422   using native_handle_type = typename basic_filebuf<_CharT, _Traits>::native_handle_type;
1423 #    endif
1424 
1425   _LIBCPP_HIDE_FROM_ABI basic_fstream();
1426   _LIBCPP_HIDE_FROM_ABI explicit basic_fstream(const char* __s,
1427                                                ios_base::openmode __mode = ios_base::in | ios_base::out);
1428 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1429   _LIBCPP_HIDE_FROM_ABI explicit basic_fstream(const wchar_t* __s,
1430                                                ios_base::openmode __mode = ios_base::in | ios_base::out);
1431 #    endif
1432   _LIBCPP_HIDE_FROM_ABI explicit basic_fstream(const string& __s,
1433                                                ios_base::openmode __mode = ios_base::in | ios_base::out);
1434 
1435 #    if _LIBCPP_STD_VER >= 17
1436   template <class _Tp, class = enable_if_t<is_same_v<_Tp, filesystem::path>>>
1437   _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI explicit basic_fstream(
1438       const _Tp& __p, ios_base::openmode __mode = ios_base::in | ios_base::out)
1439       : basic_fstream(__p.c_str(), __mode) {}
1440 #    endif // _LIBCPP_STD_VER >= 17
1441 
1442   _LIBCPP_HIDE_FROM_ABI basic_fstream(basic_fstream&& __rhs);
1443 
1444   _LIBCPP_HIDE_FROM_ABI basic_fstream& operator=(basic_fstream&& __rhs);
1445 
1446   _LIBCPP_HIDE_FROM_ABI void swap(basic_fstream& __rhs);
1447 
1448   _LIBCPP_HIDE_FROM_ABI basic_filebuf<char_type, traits_type>* rdbuf() const;
1449 #    if _LIBCPP_STD_VER >= 26
1450   _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() const noexcept { return rdbuf()->native_handle(); }
1451 #    endif
1452   _LIBCPP_HIDE_FROM_ABI bool is_open() const;
1453   _LIBCPP_HIDE_FROM_ABI void open(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1454 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1455   void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1456 #    endif
1457   _LIBCPP_HIDE_FROM_ABI void open(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1458 
1459 #    if _LIBCPP_STD_VER >= 17
1460   _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI void
1461   open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in | ios_base::out) {
1462     return open(__p.c_str(), __mode);
1463   }
1464 #    endif // _LIBCPP_STD_VER >= 17
1465 
1466   _LIBCPP_HIDE_FROM_ABI void close();
1467 
1468 private:
1469   basic_filebuf<char_type, traits_type> __sb_;
1470 };
1471 
1472 template <class _CharT, class _Traits>
1473 inline basic_fstream<_CharT, _Traits>::basic_fstream()
1474     : basic_iostream<char_type, traits_type>(std::addressof(__sb_)) {}
1475 
1476 template <class _CharT, class _Traits>
1477 inline basic_fstream<_CharT, _Traits>::basic_fstream(const char* __s, ios_base::openmode __mode)
1478     : basic_iostream<char_type, traits_type>(std::addressof(__sb_)) {
1479   if (__sb_.open(__s, __mode) == nullptr)
1480     this->setstate(ios_base::failbit);
1481 }
1482 
1483 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1484 template <class _CharT, class _Traits>
1485 inline basic_fstream<_CharT, _Traits>::basic_fstream(const wchar_t* __s, ios_base::openmode __mode)
1486     : basic_iostream<char_type, traits_type>(std::addressof(__sb_)) {
1487   if (__sb_.open(__s, __mode) == nullptr)
1488     this->setstate(ios_base::failbit);
1489 }
1490 #    endif
1491 
1492 template <class _CharT, class _Traits>
1493 inline basic_fstream<_CharT, _Traits>::basic_fstream(const string& __s, ios_base::openmode __mode)
1494     : basic_iostream<char_type, traits_type>(std::addressof(__sb_)) {
1495   if (__sb_.open(__s, __mode) == nullptr)
1496     this->setstate(ios_base::failbit);
1497 }
1498 
1499 // extension
1500 template <class _CharT, class _Traits>
1501 inline basic_fstream<_CharT, _Traits>::basic_fstream(basic_fstream&& __rhs)
1502     : basic_iostream<char_type, traits_type>(std::move(__rhs)), __sb_(std::move(__rhs.__sb_)) {
1503   this->set_rdbuf(std::addressof(__sb_));
1504 }
1505 
1506 template <class _CharT, class _Traits>
1507 inline basic_fstream<_CharT, _Traits>& basic_fstream<_CharT, _Traits>::operator=(basic_fstream&& __rhs) {
1508   basic_iostream<char_type, traits_type>::operator=(std::move(__rhs));
1509   __sb_ = std::move(__rhs.__sb_);
1510   return *this;
1511 }
1512 
1513 template <class _CharT, class _Traits>
1514 inline void basic_fstream<_CharT, _Traits>::swap(basic_fstream& __rhs) {
1515   basic_iostream<char_type, traits_type>::swap(__rhs);
1516   __sb_.swap(__rhs.__sb_);
1517 }
1518 
1519 template <class _CharT, class _Traits>
1520 inline _LIBCPP_HIDE_FROM_ABI void swap(basic_fstream<_CharT, _Traits>& __x, basic_fstream<_CharT, _Traits>& __y) {
1521   __x.swap(__y);
1522 }
1523 
1524 template <class _CharT, class _Traits>
1525 inline basic_filebuf<_CharT, _Traits>* basic_fstream<_CharT, _Traits>::rdbuf() const {
1526   return const_cast<basic_filebuf<char_type, traits_type>*>(std::addressof(__sb_));
1527 }
1528 
1529 template <class _CharT, class _Traits>
1530 inline bool basic_fstream<_CharT, _Traits>::is_open() const {
1531   return __sb_.is_open();
1532 }
1533 
1534 template <class _CharT, class _Traits>
1535 void basic_fstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
1536   if (__sb_.open(__s, __mode))
1537     this->clear();
1538   else
1539     this->setstate(ios_base::failbit);
1540 }
1541 
1542 #    if _LIBCPP_HAS_OPEN_WITH_WCHAR
1543 template <class _CharT, class _Traits>
1544 void basic_fstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {
1545   if (__sb_.open(__s, __mode))
1546     this->clear();
1547   else
1548     this->setstate(ios_base::failbit);
1549 }
1550 #    endif
1551 
1552 template <class _CharT, class _Traits>
1553 void basic_fstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {
1554   if (__sb_.open(__s, __mode))
1555     this->clear();
1556   else
1557     this->setstate(ios_base::failbit);
1558 }
1559 
1560 template <class _CharT, class _Traits>
1561 inline void basic_fstream<_CharT, _Traits>::close() {
1562   if (__sb_.close() == nullptr)
1563     this->setstate(ios_base::failbit);
1564 }
1565 
1566 #    if _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1
1567 extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ifstream<char>;
1568 extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ofstream<char>;
1569 extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_filebuf<char>;
1570 #    endif
1571 
1572 _LIBCPP_END_NAMESPACE_STD
1573 
1574 _LIBCPP_POP_MACROS
1575 
1576 #  endif // _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION
1577 
1578 #  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1579 #    include <atomic>
1580 #    include <concepts>
1581 #    include <cstdlib>
1582 #    include <iosfwd>
1583 #    include <limits>
1584 #    include <mutex>
1585 #    include <new>
1586 #    include <stdexcept>
1587 #    include <type_traits>
1588 #  endif
1589 
1590 #  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 23
1591 #    include <filesystem>
1592 #  endif
1593 #endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
1594 
1595 #endif // _LIBCPP_FSTREAM