// -*- C++ -*-

//===----------------------------------------------------------------------===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_FSTREAM

#define _LIBCPP_FSTREAM

/*

    fstream synopsis

template <class charT, class traits = char_traits<charT> >

class basic_filebuf

    : public basic_streambuf<charT, traits>

{

public:

    typedef charT                          char_type;

    typedef traits                         traits_type;

    typedef typename traits_type::int_type int_type;

    typedef typename traits_type::pos_type pos_type;

    typedef typename traits_type::off_type off_type;

    // 27.9.1.2 Constructors/destructor:

    basic_filebuf();

    basic_filebuf(basic_filebuf&& rhs);

    virtual ~basic_filebuf();

    // 27.9.1.3 Assign/swap:

    basic_filebuf& operator=(basic_filebuf&& rhs);

    void swap(basic_filebuf& rhs);

    // 27.9.1.4 Members:

    bool is_open() const;

    basic_filebuf* open(const char* s, ios_base::openmode mode);

    basic_filebuf* open(const string& s, ios_base::openmode mode);

    basic_filebuf* open(const filesystem::path& p, ios_base::openmode mode); // C++17

    basic_filebuf* close();

protected:

    // 27.9.1.5 Overridden virtual functions:

    virtual streamsize showmanyc();

    virtual int_type underflow();

    virtual int_type uflow();

    virtual int_type pbackfail(int_type c = traits_type::eof());

    virtual int_type overflow (int_type c = traits_type::eof());

    virtual basic_streambuf<char_type, traits_type>* setbuf(char_type* s, streamsize n);

    virtual pos_type seekoff(off_type off, ios_base::seekdir way,

                             ios_base::openmode which = ios_base::in | ios_base::out);

    virtual pos_type seekpos(pos_type sp,

                             ios_base::openmode which = ios_base::in | ios_base::out);

    virtual int sync();

    virtual void imbue(const locale& loc);

};

template <class charT, class traits>

  void

  swap(basic_filebuf<charT, traits>& x, basic_filebuf<charT, traits>& y);

typedef basic_filebuf<char>    filebuf;

typedef basic_filebuf<wchar_t> wfilebuf;

template <class charT, class traits = char_traits<charT> >

class basic_ifstream

    : public basic_istream<charT,traits>

{

public:

    typedef charT                          char_type;

    typedef traits                         traits_type;

    typedef typename traits_type::int_type int_type;

    typedef typename traits_type::pos_type pos_type;

    typedef typename traits_type::off_type off_type;

    using native_handle_type = typename basic_filebuf<charT, traits>::native_handle_type; // Since C++26

    basic_ifstream();

    explicit basic_ifstream(const char* s, ios_base::openmode mode = ios_base::in);

    explicit basic_ifstream(const string& s, ios_base::openmode mode = ios_base::in);

    explicit basic_ifstream(const filesystem::path& p,

                            ios_base::openmode mode = ios_base::in); // C++17

    basic_ifstream(basic_ifstream&& rhs);

    basic_ifstream& operator=(basic_ifstream&& rhs);

    void swap(basic_ifstream& rhs);

    basic_filebuf<char_type, traits_type>* rdbuf() const;

    native_handle_type native_handle() const noexcept; // Since C++26

    bool is_open() const;

    void open(const char* s, ios_base::openmode mode = ios_base::in);

    void open(const string& s, ios_base::openmode mode = ios_base::in);

    void open(const filesystem::path& s, ios_base::openmode mode = ios_base::in); // C++17

    void close();

};

template <class charT, class traits>

  void

  swap(basic_ifstream<charT, traits>& x, basic_ifstream<charT, traits>& y);

typedef basic_ifstream<char>    ifstream;

typedef basic_ifstream<wchar_t> wifstream;

template <class charT, class traits = char_traits<charT> >

class basic_ofstream

    : public basic_ostream<charT,traits>

{

public:

    typedef charT                          char_type;

    typedef traits                         traits_type;

    typedef typename traits_type::int_type int_type;

    typedef typename traits_type::pos_type pos_type;

    typedef typename traits_type::off_type off_type;

    using native_handle_type = typename basic_filebuf<charT, traits>::native_handle_type; // Since C++26

    basic_ofstream();

    explicit basic_ofstream(const char* s, ios_base::openmode mode = ios_base::out);

    explicit basic_ofstream(const string& s, ios_base::openmode mode = ios_base::out);

    explicit basic_ofstream(const filesystem::path& p,

                            ios_base::openmode mode = ios_base::out); // C++17

    basic_ofstream(basic_ofstream&& rhs);

    basic_ofstream& operator=(basic_ofstream&& rhs);

    void swap(basic_ofstream& rhs);

    basic_filebuf<char_type, traits_type>* rdbuf() const;

    native_handle_type native_handle() const noexcept; // Since C++26

    bool is_open() const;

    void open(const char* s, ios_base::openmode mode = ios_base::out);

    void open(const string& s, ios_base::openmode mode = ios_base::out);

    void open(const filesystem::path& p,

              ios_base::openmode mode = ios_base::out); // C++17

    void close();

};

template <class charT, class traits>

  void

  swap(basic_ofstream<charT, traits>& x, basic_ofstream<charT, traits>& y);

typedef basic_ofstream<char>    ofstream;

typedef basic_ofstream<wchar_t> wofstream;

template <class charT, class traits=char_traits<charT> >

class basic_fstream

    : public basic_iostream<charT,traits>

{

public:

    typedef charT                          char_type;

    typedef traits                         traits_type;

    typedef typename traits_type::int_type int_type;

    typedef typename traits_type::pos_type pos_type;

    typedef typename traits_type::off_type off_type;

    using native_handle_type = typename basic_filebuf<charT, traits>::native_handle_type; // Since C++26

    basic_fstream();

    explicit basic_fstream(const char* s, ios_base::openmode mode = ios_base::in|ios_base::out);

    explicit basic_fstream(const string& s, ios_base::openmode mode = ios_base::in|ios_base::out);

    explicit basic_fstream(const filesystem::path& p,

                           ios_base::openmode mode = ios_base::in|ios_base::out); C++17

    basic_fstream(basic_fstream&& rhs);

    basic_fstream& operator=(basic_fstream&& rhs);

    void swap(basic_fstream& rhs);

    basic_filebuf<char_type, traits_type>* rdbuf() const;

    native_handle_type native_handle() const noexcept; // Since C++26

    bool is_open() const;

    void open(const char* s, ios_base::openmode mode = ios_base::in|ios_base::out);

    void open(const string& s, ios_base::openmode mode = ios_base::in|ios_base::out);

    void open(const filesystem::path& s,

              ios_base::openmode mode = ios_base::in|ios_base::out); // C++17

    void close();

};

template <class charT, class traits>

  void swap(basic_fstream<charT, traits>& x, basic_fstream<charT, traits>& y);

typedef basic_fstream<char>    fstream;

typedef basic_fstream<wchar_t> wfstream;

}  // std

*/

#include <__algorithm/max.h>

#include <__assert> // all public C++ headers provide the assertion handler

#include <__availability>

#include <__config>

#include <__fwd/fstream.h>

#include <__locale>

#include <__utility/move.h>

#include <__utility/swap.h>

#include <__utility/unreachable.h>

#include <cstdio>

#include <filesystem>

#include <istream>

#include <ostream>

#include <typeinfo>

#include <version>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

#  pragma GCC system_header

#endif

_LIBCPP_PUSH_MACROS

#include <__undef_macros>

#if defined(_LIBCPP_MSVCRT) || defined(_NEWLIB_VERSION)

#  define _LIBCPP_HAS_NO_OFF_T_FUNCTIONS

#endif

#if !defined(_LIBCPP_HAS_NO_FILESYSTEM)

_LIBCPP_BEGIN_NAMESPACE_STD

#  if _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_WIN32API)

_LIBCPP_EXPORTED_FROM_ABI void* __filebuf_windows_native_handle(FILE* __file) noexcept;

#  endif

template <class _CharT, class _Traits>

class _LIBCPP_TEMPLATE_VIS basic_filebuf : public basic_streambuf<_CharT, _Traits> {

public:

  typedef _CharT char_type;

  typedef _Traits traits_type;

  typedef typename traits_type::int_type int_type;

  typedef typename traits_type::pos_type pos_type;

  typedef typename traits_type::off_type off_type;

  typedef typename traits_type::state_type state_type;

#  if _LIBCPP_STD_VER >= 26

#    if defined(_LIBCPP_WIN32API)

  using native_handle_type = void*; // HANDLE

#    elif __has_include(<unistd.h>)

  using native_handle_type = int; // POSIX file descriptor

#    else

#      error "Provide a native file handle!"

#    endif

#  endif

  // 27.9.1.2 Constructors/destructor:

  basic_filebuf();

  basic_filebuf(basic_filebuf&& __rhs);

  ~basic_filebuf() override;

  // 27.9.1.3 Assign/swap:

  _LIBCPP_HIDE_FROM_ABI basic_filebuf& operator=(basic_filebuf&& __rhs);

  void swap(basic_filebuf& __rhs);

  // 27.9.1.4 Members:

  _LIBCPP_HIDE_FROM_ABI bool is_open() const;

  basic_filebuf* open(const char* __s, ios_base::openmode __mode);

#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR

  basic_filebuf* open(const wchar_t* __s, ios_base::openmode __mode);

#  endif

  _LIBCPP_HIDE_FROM_ABI basic_filebuf* open(const string& __s, ios_base::openmode __mode);

#  if _LIBCPP_STD_VER >= 17

  _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI basic_filebuf*

  open(const filesystem::path& __p, ios_base::openmode __mode) {

    return open(__p.c_str(), __mode);

  }

#  endif

  _LIBCPP_HIDE_FROM_ABI basic_filebuf* __open(int __fd, ios_base::openmode __mode);

  basic_filebuf* close();

#  if _LIBCPP_STD_VER >= 26

  _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() const noexcept {

    _LIBCPP_ASSERT_UNCATEGORIZED(this->is_open(), "File must be opened");

#    if defined(_LIBCPP_WIN32API)

    return std::__filebuf_windows_native_handle(__file_);

#    elif __has_include(<unistd.h>)

    return fileno(__file_);

#    else

#      error "Provide a way to determine the file native handle!"

#    endif

  }

#  endif //  _LIBCPP_STD_VER >= 26

  _LIBCPP_HIDE_FROM_ABI inline static const char* __make_mdstring(ios_base::openmode __mode) _NOEXCEPT;

protected:

  // 27.9.1.5 Overridden virtual functions:

  int_type underflow() override;

  int_type pbackfail(int_type __c = traits_type::eof()) override;

  int_type overflow(int_type __c = traits_type::eof()) override;

  basic_streambuf<char_type, traits_type>* setbuf(char_type* __s, streamsize __n) override;

  pos_type

  seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __wch = ios_base::in | ios_base::out) override;

  pos_type seekpos(pos_type __sp, ios_base::openmode __wch = ios_base::in | ios_base::out) override;

  int sync() override;

  void imbue(const locale& __loc) override;

private:

  char* __extbuf_;

  const char* __extbufnext_;

  const char* __extbufend_;

  char __extbuf_min_[8];

  size_t __ebs_;

  char_type* __intbuf_;

  size_t __ibs_;

  FILE* __file_;

  const codecvt<char_type, char, state_type>* __cv_;

  state_type __st_;

  state_type __st_last_;

  ios_base::openmode __om_;

  ios_base::openmode __cm_;

  bool __owns_eb_;

  bool __owns_ib_;

  bool __always_noconv_;

  bool __read_mode();

  void __write_mode();

  _LIBCPP_EXPORTED_FROM_ABI friend FILE* __get_ostream_file(ostream&);

};

template <class _CharT, class _Traits>

basic_filebuf<_CharT, _Traits>::basic_filebuf()

    : __extbuf_(nullptr),

      __extbufnext_(nullptr),

      __extbufend_(nullptr),

      __ebs_(0),

      __intbuf_(nullptr),

      __ibs_(0),

      __file_(nullptr),

      __cv_(nullptr),

      __st_(),

      __st_last_(),

      __om_(0),

      __cm_(0),

      __owns_eb_(false),

      __owns_ib_(false),

      __always_noconv_(false) {

  if (std::has_facet<codecvt<char_type, char, state_type> >(this->getloc())) {

    __cv_            = &std::use_facet<codecvt<char_type, char, state_type> >(this->getloc());

    __always_noconv_ = __cv_->always_noconv();

  }

  setbuf(nullptr, 4096);

}

template <class _CharT, class _Traits>

basic_filebuf<_CharT, _Traits>::basic_filebuf(basic_filebuf&& __rhs) : basic_streambuf<_CharT, _Traits>(__rhs) {

  if (__rhs.__extbuf_ == __rhs.__extbuf_min_) {

    __extbuf_     = __extbuf_min_;

    __extbufnext_ = __extbuf_ + (__rhs.__extbufnext_ - __rhs.__extbuf_);

    __extbufend_  = __extbuf_ + (__rhs.__extbufend_ - __rhs.__extbuf_);

  } else {

    __extbuf_     = __rhs.__extbuf_;

    __extbufnext_ = __rhs.__extbufnext_;

    __extbufend_  = __rhs.__extbufend_;

  }

  __ebs_           = __rhs.__ebs_;

  __intbuf_        = __rhs.__intbuf_;

  __ibs_           = __rhs.__ibs_;

  __file_          = __rhs.__file_;

  __cv_            = __rhs.__cv_;

  __st_            = __rhs.__st_;

  __st_last_       = __rhs.__st_last_;

  __om_            = __rhs.__om_;

  __cm_            = __rhs.__cm_;

  __owns_eb_       = __rhs.__owns_eb_;

  __owns_ib_       = __rhs.__owns_ib_;

  __always_noconv_ = __rhs.__always_noconv_;

  if (__rhs.pbase()) {

    if (__rhs.pbase() == __rhs.__intbuf_)

      this->setp(__intbuf_, __intbuf_ + (__rhs.epptr() - __rhs.pbase()));

    else

      this->setp((char_type*)__extbuf_, (char_type*)__extbuf_ + (__rhs.epptr() - __rhs.pbase()));

    this->__pbump(__rhs.pptr() - __rhs.pbase());

  } else if (__rhs.eback()) {

    if (__rhs.eback() == __rhs.__intbuf_)

      this->setg(__intbuf_, __intbuf_ + (__rhs.gptr() - __rhs.eback()), __intbuf_ + (__rhs.egptr() - __rhs.eback()));

    else

      this->setg((char_type*)__extbuf_,

                 (char_type*)__extbuf_ + (__rhs.gptr() - __rhs.eback()),

                 (char_type*)__extbuf_ + (__rhs.egptr() - __rhs.eback()));

  }

  __rhs.__extbuf_     = nullptr;

  __rhs.__extbufnext_ = nullptr;

  __rhs.__extbufend_  = nullptr;

  __rhs.__ebs_        = 0;

  __rhs.__intbuf_     = 0;

  __rhs.__ibs_        = 0;

  __rhs.__file_       = nullptr;

  __rhs.__st_         = state_type();

  __rhs.__st_last_    = state_type();

  __rhs.__om_         = 0;

  __rhs.__cm_         = 0;

  __rhs.__owns_eb_    = false;

  __rhs.__owns_ib_    = false;

  __rhs.setg(0, 0, 0);

  __rhs.setp(0, 0);

}

template <class _CharT, class _Traits>

inline basic_filebuf<_CharT, _Traits>& basic_filebuf<_CharT, _Traits>::operator=(basic_filebuf&& __rhs) {

  close();

  swap(__rhs);

  return *this;

}

template <class _CharT, class _Traits>

basic_filebuf<_CharT, _Traits>::~basic_filebuf() {

#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS

  try {

#  endif // _LIBCPP_HAS_NO_EXCEPTIONS

    close();

#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS

  } catch (...) {

  }

#  endif // _LIBCPP_HAS_NO_EXCEPTIONS

  if (__owns_eb_)

    delete[] __extbuf_;

  if (__owns_ib_)

    delete[] __intbuf_;

}

template <class _CharT, class _Traits>

void basic_filebuf<_CharT, _Traits>::swap(basic_filebuf& __rhs) {

  basic_streambuf<char_type, traits_type>::swap(__rhs);

  if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_) {

    // Neither *this nor __rhs uses the small buffer, so we can simply swap the pointers.

    std::swap(__extbuf_, __rhs.__extbuf_);

    std::swap(__extbufnext_, __rhs.__extbufnext_);

    std::swap(__extbufend_, __rhs.__extbufend_);

  } else {

    ptrdiff_t __ln = __extbufnext_ ? __extbufnext_ - __extbuf_ : 0;

    ptrdiff_t __le = __extbufend_ ? __extbufend_ - __extbuf_ : 0;

    ptrdiff_t __rn = __rhs.__extbufnext_ ? __rhs.__extbufnext_ - __rhs.__extbuf_ : 0;

    ptrdiff_t __re = __rhs.__extbufend_ ? __rhs.__extbufend_ - __rhs.__extbuf_ : 0;

    if (__extbuf_ == __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_) {

      // *this uses the small buffer, but __rhs doesn't.

      __extbuf_       = __rhs.__extbuf_;

      __rhs.__extbuf_ = __rhs.__extbuf_min_;

      std::memmove(__rhs.__extbuf_min_, __extbuf_min_, sizeof(__extbuf_min_));

    } else if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ == __rhs.__extbuf_min_) {

      // *this doesn't use the small buffer, but __rhs does.

      __rhs.__extbuf_ = __extbuf_;

      __extbuf_       = __extbuf_min_;

      std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));

    } else {

      // Both *this and __rhs use the small buffer.

      char __tmp[sizeof(__extbuf_min_)];

      std::memmove(__tmp, __extbuf_min_, sizeof(__extbuf_min_));

      std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));

      std::memmove(__rhs.__extbuf_min_, __tmp, sizeof(__extbuf_min_));

    }

    __extbufnext_       = __extbuf_ + __rn;

    __extbufend_        = __extbuf_ + __re;

    __rhs.__extbufnext_ = __rhs.__extbuf_ + __ln;

    __rhs.__extbufend_  = __rhs.__extbuf_ + __le;

  }

  std::swap(__ebs_, __rhs.__ebs_);

  std::swap(__intbuf_, __rhs.__intbuf_);

  std::swap(__ibs_, __rhs.__ibs_);

  std::swap(__file_, __rhs.__file_);

  std::swap(__cv_, __rhs.__cv_);

  std::swap(__st_, __rhs.__st_);

  std::swap(__st_last_, __rhs.__st_last_);

  std::swap(__om_, __rhs.__om_);

  std::swap(__cm_, __rhs.__cm_);

  std::swap(__owns_eb_, __rhs.__owns_eb_);

  std::swap(__owns_ib_, __rhs.__owns_ib_);

  std::swap(__always_noconv_, __rhs.__always_noconv_);

  if (this->eback() == (char_type*)__rhs.__extbuf_min_) {

    ptrdiff_t __n = this->gptr() - this->eback();

    ptrdiff_t __e = this->egptr() - this->eback();

    this->setg((char_type*)__extbuf_min_, (char_type*)__extbuf_min_ + __n, (char_type*)__extbuf_min_ + __e);

  } else if (this->pbase() == (char_type*)__rhs.__extbuf_min_) {

    ptrdiff_t __n = this->pptr() - this->pbase();

    ptrdiff_t __e = this->epptr() - this->pbase();

    this->setp((char_type*)__extbuf_min_, (char_type*)__extbuf_min_ + __e);

    this->__pbump(__n);

  }

  if (__rhs.eback() == (char_type*)__extbuf_min_) {

    ptrdiff_t __n = __rhs.gptr() - __rhs.eback();

    ptrdiff_t __e = __rhs.egptr() - __rhs.eback();

    __rhs.setg(

        (char_type*)__rhs.__extbuf_min_, (char_type*)__rhs.__extbuf_min_ + __n, (char_type*)__rhs.__extbuf_min_ + __e);

  } else if (__rhs.pbase() == (char_type*)__extbuf_min_) {

    ptrdiff_t __n = __rhs.pptr() - __rhs.pbase();

    ptrdiff_t __e = __rhs.epptr() - __rhs.pbase();

    __rhs.setp((char_type*)__rhs.__extbuf_min_, (char_type*)__rhs.__extbuf_min_ + __e);

    __rhs.__pbump(__n);

  }

}

template <class _CharT, class _Traits>

inline _LIBCPP_HIDE_FROM_ABI void swap(basic_filebuf<_CharT, _Traits>& __x, basic_filebuf<_CharT, _Traits>& __y) {

  __x.swap(__y);

}

template <class _CharT, class _Traits>

inline bool basic_filebuf<_CharT, _Traits>::is_open() const {

  return __file_ != nullptr;

}

template <class _CharT, class _Traits>

const char* basic_filebuf<_CharT, _Traits>::__make_mdstring(ios_base::openmode __mode) _NOEXCEPT {

  switch (__mode & ~ios_base::ate) {

  case ios_base::out:

  case ios_base::out | ios_base::trunc:

    return "w" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::out | ios_base::app:

  case ios_base::app:

    return "a" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in:

    return "r" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::out:

    return "r+" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::out | ios_base::trunc:

    return "w+" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::out | ios_base::app:

  case ios_base::in | ios_base::app:

    return "a+" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::out | ios_base::binary:

  case ios_base::out | ios_base::trunc | ios_base::binary:

    return "wb" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::out | ios_base::app | ios_base::binary:

  case ios_base::app | ios_base::binary:

    return "ab" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::binary:

    return "rb" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::out | ios_base::binary:

    return "r+b" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:

    return "w+b" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:

  case ios_base::in | ios_base::app | ios_base::binary:

    return "a+b" _LIBCPP_FOPEN_CLOEXEC_MODE;

#  if _LIBCPP_STD_VER >= 23

  case ios_base::out | ios_base::noreplace:

  case ios_base::out | ios_base::trunc | ios_base::noreplace:

    return "wx" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:

    return "w+x" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::out | ios_base::binary | ios_base::noreplace:

  case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:

    return "wbx" _LIBCPP_FOPEN_CLOEXEC_MODE;

  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:

    return "w+bx" _LIBCPP_FOPEN_CLOEXEC_MODE;

#  endif // _LIBCPP_STD_VER >= 23

  default:

    return nullptr;

  }

  __libcpp_unreachable();

}

template <class _CharT, class _Traits>

basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {

  basic_filebuf<_CharT, _Traits>* __rt = nullptr;

  if (__file_ == nullptr) {

    if (const char* __mdstr = __make_mdstring(__mode)) {

      __rt    = this;

      __file_ = fopen(__s, __mdstr);

      if (__file_) {

        __om_ = __mode;

        if (__mode & ios_base::ate) {

          if (fseek(__file_, 0, SEEK_END)) {

            fclose(__file_);

            __file_ = nullptr;

            __rt    = nullptr;

          }

        }

      } else

        __rt = nullptr;

    }

  }

  return __rt;

}

template <class _CharT, class _Traits>

inline basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {

  basic_filebuf<_CharT, _Traits>* __rt = nullptr;

  if (__file_ == nullptr) {

    if (const char* __mdstr = __make_mdstring(__mode)) {

      __rt    = this;

      __file_ = fdopen(__fd, __mdstr);

      if (__file_) {

        __om_ = __mode;

        if (__mode & ios_base::ate) {

          if (fseek(__file_, 0, SEEK_END)) {

            fclose(__file_);

            __file_ = nullptr;

            __rt    = nullptr;

          }

        }

      } else

        __rt = nullptr;

    }

  }

  return __rt;

}

#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR

// This is basically the same as the char* overload except that it uses _wfopen

// and long mode strings.

template <class _CharT, class _Traits>

basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {

  basic_filebuf<_CharT, _Traits>* __rt = nullptr;

  if (__file_ == nullptr) {

    __rt = this;

    const wchar_t* __mdstr;

    switch (__mode & ~ios_base::ate) {

    case ios_base::out:

    case ios_base::out | ios_base::trunc:

      __mdstr = L"w";

      break;

    case ios_base::out | ios_base::app:

    case ios_base::app:

      __mdstr = L"a";

      break;

    case ios_base::in:

      __mdstr = L"r";

      break;

    case ios_base::in | ios_base::out:

      __mdstr = L"r+";

      break;

    case ios_base::in | ios_base::out | ios_base::trunc:

      __mdstr = L"w+";

      break;

    case ios_base::in | ios_base::out | ios_base::app:

    case ios_base::in | ios_base::app:

      __mdstr = L"a+";

      break;

    case ios_base::out | ios_base::binary:

    case ios_base::out | ios_base::trunc | ios_base::binary:

      __mdstr = L"wb";

      break;

    case ios_base::out | ios_base::app | ios_base::binary:

    case ios_base::app | ios_base::binary:

      __mdstr = L"ab";

      break;

    case ios_base::in | ios_base::binary:

      __mdstr = L"rb";

      break;

    case ios_base::in | ios_base::out | ios_base::binary:

      __mdstr = L"r+b";

      break;

    case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:

      __mdstr = L"w+b";

      break;

    case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:

    case ios_base::in | ios_base::app | ios_base::binary:

      __mdstr = L"a+b";

      break;

#    if _LIBCPP_STD_VER >= 23

    case ios_base::out | ios_base::noreplace:

    case ios_base::out | ios_base::trunc | ios_base::noreplace:

      __mdstr = L"wx";

      break;

    case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:

      __mdstr = L"w+x";

      break;

    case ios_base::out | ios_base::binary | ios_base::noreplace:

    case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:

      __mdstr = L"wbx";

      break;

    case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:

      __mdstr = L"w+bx";

      break;

#    endif // _LIBCPP_STD_VER >= 23

    default:

      __rt = nullptr;

      break;

    }

    if (__rt) {

      __file_ = _wfopen(__s, __mdstr);

      if (__file_) {

        __om_ = __mode;

        if (__mode & ios_base::ate) {

          if (fseek(__file_, 0, SEEK_END)) {

            fclose(__file_);

            __file_ = nullptr;

            __rt    = nullptr;

          }

        }

      } else

        __rt = nullptr;

    }

  }

  return __rt;

}

#  endif

template <class _CharT, class _Traits>

inline basic_filebuf<_CharT, _Traits>*

basic_filebuf<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {

  return open(__s.c_str(), __mode);

}

template <class _CharT, class _Traits>

basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::close() {

  basic_filebuf<_CharT, _Traits>* __rt = nullptr;

  if (__file_) {

    __rt = this;

    unique_ptr<FILE, int (*)(FILE*)> __h(__file_, fclose);

    if (sync())

      __rt = nullptr;

    if (fclose(__h.release()))

      __rt = nullptr;

    __file_ = nullptr;

    setbuf(0, 0);

  }

  return __rt;

}

template <class _CharT, class _Traits>

typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::underflow() {

  if (__file_ == nullptr)

    return traits_type::eof();

  bool __initial = __read_mode();

  char_type __1buf;

  if (this->gptr() == nullptr)

    this->setg(&__1buf, &__1buf + 1, &__1buf + 1);

  const size_t __unget_sz = __initial ? 0 : std::min<size_t>((this->egptr() - this->eback()) / 2, 4);

  int_type __c            = traits_type::eof();

  if (this->gptr() == this->egptr()) {

    std::memmove(this->eback(), this->egptr() - __unget_sz, __unget_sz * sizeof(char_type));

    if (__always_noconv_) {

      size_t __nmemb = static_cast<size_t>(this->egptr() - this->eback() - __unget_sz);

      __nmemb        = ::fread(this->eback() + __unget_sz, 1, __nmemb, __file_);

      if (__nmemb != 0) {

        this->setg(this->eback(), this->eback() + __unget_sz, this->eback() + __unget_sz + __nmemb);

        __c = traits_type::to_int_type(*this->gptr());

      }

    } else {

      if (__extbufend_ != __extbufnext_) {

        _LIBCPP_ASSERT_NON_NULL(__extbufnext_ != nullptr, "underflow moving from nullptr");

        _LIBCPP_ASSERT_NON_NULL(__extbuf_ != nullptr, "underflow moving into nullptr");

        std::memmove(__extbuf_, __extbufnext_, __extbufend_ - __extbufnext_);

      }

      __extbufnext_ = __extbuf_ + (__extbufend_ - __extbufnext_);

      __extbufend_  = __extbuf_ + (__extbuf_ == __extbuf_min_ ? sizeof(__extbuf_min_) : __ebs_);

      size_t __nmemb =

          std::min(static_cast<size_t>(__ibs_ - __unget_sz), static_cast<size_t>(__extbufend_ - __extbufnext_));

      codecvt_base::result __r;

      __st_last_  = __st_;

      size_t __nr = fread((void*)const_cast<char*>(__extbufnext_), 1, __nmemb, __file_);

      if (__nr != 0) {

        if (!__cv_)

          __throw_bad_cast();

        __extbufend_ = __extbufnext_ + __nr;

        char_type* __inext;

        __r = __cv_->in(

            __st_, __extbuf_, __extbufend_, __extbufnext_, this->eback() + __unget_sz, this->eback() + __ibs_, __inext);

        if (__r == codecvt_base::noconv) {

          this->setg((char_type*)__extbuf_, (char_type*)__extbuf_, (char_type*)const_cast<char*>(__extbufend_));

          __c = traits_type::to_int_type(*this->gptr());

        } else if (__inext != this->eback() + __unget_sz) {

          this->setg(this->eback(), this->eback() + __unget_sz, __inext);

          __c = traits_type::to_int_type(*this->gptr());

        }

      }

    }

  } else

    __c = traits_type::to_int_type(*this->gptr());

  if (this->eback() == &__1buf)

    this->setg(nullptr, nullptr, nullptr);

  return __c;

}

template <class _CharT, class _Traits>

typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::pbackfail(int_type __c) {

  if (__file_ && this->eback() < this->gptr()) {

    if (traits_type::eq_int_type(__c, traits_type::eof())) {

      this->gbump(-1);

      return traits_type::not_eof(__c);

    }

    if ((__om_ & ios_base::out) || traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1])) {

      this->gbump(-1);

      *this->gptr() = traits_type::to_char_type(__c);

      return __c;

    }

  }

  return traits_type::eof();

}

template <class _CharT, class _Traits>

typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::overflow(int_type __c) {

  if (__file_ == nullptr)

    return traits_type::eof();

  __write_mode();

  char_type __1buf;

  char_type* __pb_save  = this->pbase();

  char_type* __epb_save = this->epptr();

  if (!traits_type::eq_int_type(__c, traits_type::eof())) {

    if (this->pptr() == nullptr)

      this->setp(&__1buf, &__1buf + 1);

    *this->pptr() = traits_type::to_char_type(__c);

    this->pbump(1);

  }

  if (this->pptr() != this->pbase()) {

    if (__always_noconv_) {

      size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());

      if (std::fwrite(this->pbase(), sizeof(char_type), __nmemb, __file_) != __nmemb)

        return traits_type::eof();

    } else {

      char* __extbe = __extbuf_;

      codecvt_base::result __r;

      do {

        if (!__cv_)

          __throw_bad_cast();

        const char_type* __e;

        __r = __cv_->out(__st_, this->pbase(), this->pptr(), __e, __extbuf_, __extbuf_ + __ebs_, __extbe);

        if (__e == this->pbase())

          return traits_type::eof();

        if (__r == codecvt_base::noconv) {

          size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());

          if (std::fwrite(this->pbase(), 1, __nmemb, __file_) != __nmemb)

            return traits_type::eof();

        } else if (__r == codecvt_base::ok || __r == codecvt_base::partial) {

          size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);

          if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)

            return traits_type::eof();

          if (__r == codecvt_base::partial) {

            this->setp(const_cast<char_type*>(__e), this->pptr());

            this->__pbump(this->epptr() - this->pbase());

          }

        } else

          return traits_type::eof();

      } while (__r == codecvt_base::partial);

    }

    this->setp(__pb_save, __epb_save);

  }

  return traits_type::not_eof(__c);

}

template <class _CharT, class _Traits>

basic_streambuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::setbuf(char_type* __s, streamsize __n) {

  this->setg(nullptr, nullptr, nullptr);

  this->setp(nullptr, nullptr);

  if (__owns_eb_)

    delete[] __extbuf_;

  if (__owns_ib_)

    delete[] __intbuf_;

  __ebs_ = __n;

  if (__ebs_ > sizeof(__extbuf_min_)) {

    if (__always_noconv_ && __s) {

      __extbuf_  = (char*)__s;

      __owns_eb_ = false;

    } else {

      __extbuf_  = new char[__ebs_];

      __owns_eb_ = true;

    }

  } else {

    __extbuf_  = __extbuf_min_;

    __ebs_     = sizeof(__extbuf_min_);

    __owns_eb_ = false;

  }

  if (!__always_noconv_) {

    __ibs_ = max<streamsize>(__n, sizeof(__extbuf_min_));

    if (__s && __ibs_ > sizeof(__extbuf_min_)) {

      __intbuf_  = __s;

      __owns_ib_ = false;

    } else {

      __intbuf_  = new char_type[__ibs_];

      __owns_ib_ = true;

    }

  } else {

    __ibs_     = 0;

    __intbuf_  = nullptr;

    __owns_ib_ = false;

  }

  return this;

}

template <class _CharT, class _Traits>

typename basic_filebuf<_CharT, _Traits>::pos_type

basic_filebuf<_CharT, _Traits>::seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode) {

  if (!__cv_)

    __throw_bad_cast();

  int __width = __cv_->encoding();

  if (__file_ == nullptr || (__width <= 0 && __off != 0) || sync())

    return pos_type(off_type(-1));

  // __width > 0 || __off == 0

  int __whence;

  switch (__way) {

  case ios_base::beg:

    __whence = SEEK_SET;

    break;

  case ios_base::cur:

    __whence = SEEK_CUR;

    break;

  case ios_base::end:

    __whence = SEEK_END;

    break;

  default:

    return pos_type(off_type(-1));

  }

#  if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)

  if (fseek(__file_, __width > 0 ? __width * __off : 0, __whence))

    return pos_type(off_type(-1));

  pos_type __r = ftell(__file_);

#  else

  if (::fseeko(__file_, __width > 0 ? __width * __off : 0, __whence))

    return pos_type(off_type(-1));

  pos_type __r = ftello(__file_);

#  endif

  __r.state(__st_);

  return __r;

}

template <class _CharT, class _Traits>

typename basic_filebuf<_CharT, _Traits>::pos_type

basic_filebuf<_CharT, _Traits>::seekpos(pos_type __sp, ios_base::openmode) {

  if (__file_ == nullptr || sync())

    return pos_type(off_type(-1));

#  if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)

  if (fseek(__file_, __sp, SEEK_SET))

    return pos_type(off_type(-1));

#  else

  if (::fseeko(__file_, __sp, SEEK_SET))

    return pos_type(off_type(-1));

#  endif

  __st_ = __sp.state();

  return __sp;

}

template <class _CharT, class _Traits>

int basic_filebuf<_CharT, _Traits>::sync() {

  if (__file_ == nullptr)

    return 0;

  if (!__cv_)

    __throw_bad_cast();

  if (__cm_ & ios_base::out) {

    if (this->pptr() != this->pbase())

      if (overflow() == traits_type::eof())

        return -1;

    codecvt_base::result __r;

    do {

      char* __extbe;

      __r            = __cv_->unshift(__st_, __extbuf_, __extbuf_ + __ebs_, __extbe);

      size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);

      if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)

        return -1;

    } while (__r == codecvt_base::partial);

    if (__r == codecvt_base::error)

      return -1;

    if (fflush(__file_))

      return -1;

  } else if (__cm_ & ios_base::in) {

    off_type __c;

    state_type __state = __st_last_;

    bool __update_st   = false;