1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_FSTREAM
11#define _LIBCPP_FSTREAM
12
13/*
14    fstream synopsis
15
16template <class charT, class traits = char_traits<charT> >
17class basic_filebuf
18    : public basic_streambuf<charT, traits>
19{
20public:
21    typedef charT                          char_type;
22    typedef traits                         traits_type;
23    typedef typename traits_type::int_type int_type;
24    typedef typename traits_type::pos_type pos_type;
25    typedef typename traits_type::off_type off_type;
26
27    // 27.9.1.2 Constructors/destructor:
28    basic_filebuf();
29    basic_filebuf(basic_filebuf&& rhs);
30    virtual ~basic_filebuf();
31
32    // 27.9.1.3 Assign/swap:
33    basic_filebuf& operator=(basic_filebuf&& rhs);
34    void swap(basic_filebuf& rhs);
35
36    // 27.9.1.4 Members:
37    bool is_open() const;
38    basic_filebuf* open(const char* s, ios_base::openmode mode);
39    basic_filebuf* open(const string& s, ios_base::openmode mode);
40    basic_filebuf* open(const filesystem::path& p, ios_base::openmode mode); // C++17
41    basic_filebuf* close();
42
43protected:
44    // 27.9.1.5 Overridden virtual functions:
45    virtual streamsize showmanyc();
46    virtual int_type underflow();
47    virtual int_type uflow();
48    virtual int_type pbackfail(int_type c = traits_type::eof());
49    virtual int_type overflow (int_type c = traits_type::eof());
50    virtual basic_streambuf<char_type, traits_type>* setbuf(char_type* s, streamsize n);
51    virtual pos_type seekoff(off_type off, ios_base::seekdir way,
52                             ios_base::openmode which = ios_base::in | ios_base::out);
53    virtual pos_type seekpos(pos_type sp,
54                             ios_base::openmode which = ios_base::in | ios_base::out);
55    virtual int sync();
56    virtual void imbue(const locale& loc);
57};
58
59template <class charT, class traits>
60  void
61  swap(basic_filebuf<charT, traits>& x, basic_filebuf<charT, traits>& y);
62
63typedef basic_filebuf<char>    filebuf;
64typedef basic_filebuf<wchar_t> wfilebuf;
65
66template <class charT, class traits = char_traits<charT> >
67class basic_ifstream
68    : public basic_istream<charT,traits>
69{
70public:
71    typedef charT                          char_type;
72    typedef traits                         traits_type;
73    typedef typename traits_type::int_type int_type;
74    typedef typename traits_type::pos_type pos_type;
75    typedef typename traits_type::off_type off_type;
76
77    basic_ifstream();
78    explicit basic_ifstream(const char* s, ios_base::openmode mode = ios_base::in);
79    explicit basic_ifstream(const string& s, ios_base::openmode mode = ios_base::in);
80    explicit basic_ifstream(const filesystem::path& p,
81                            ios_base::openmode mode = ios_base::in); // C++17
82    basic_ifstream(basic_ifstream&& rhs);
83
84    basic_ifstream& operator=(basic_ifstream&& rhs);
85    void swap(basic_ifstream& rhs);
86
87    basic_filebuf<char_type, traits_type>* rdbuf() const;
88    bool is_open() const;
89    void open(const char* s, ios_base::openmode mode = ios_base::in);
90    void open(const string& s, ios_base::openmode mode = ios_base::in);
91    void open(const filesystem::path& s, ios_base::openmode mode = ios_base::in); // C++17
92
93    void close();
94};
95
96template <class charT, class traits>
97  void
98  swap(basic_ifstream<charT, traits>& x, basic_ifstream<charT, traits>& y);
99
100typedef basic_ifstream<char>    ifstream;
101typedef basic_ifstream<wchar_t> wifstream;
102
103template <class charT, class traits = char_traits<charT> >
104class basic_ofstream
105    : public basic_ostream<charT,traits>
106{
107public:
108    typedef charT                          char_type;
109    typedef traits                         traits_type;
110    typedef typename traits_type::int_type int_type;
111    typedef typename traits_type::pos_type pos_type;
112    typedef typename traits_type::off_type off_type;
113
114    basic_ofstream();
115    explicit basic_ofstream(const char* s, ios_base::openmode mode = ios_base::out);
116    explicit basic_ofstream(const string& s, ios_base::openmode mode = ios_base::out);
117    explicit basic_ofstream(const filesystem::path& p,
118                            ios_base::openmode mode = ios_base::out); // C++17
119    basic_ofstream(basic_ofstream&& rhs);
120
121    basic_ofstream& operator=(basic_ofstream&& rhs);
122    void swap(basic_ofstream& rhs);
123
124    basic_filebuf<char_type, traits_type>* rdbuf() const;
125    bool is_open() const;
126    void open(const char* s, ios_base::openmode mode = ios_base::out);
127    void open(const string& s, ios_base::openmode mode = ios_base::out);
128    void open(const filesystem::path& p,
129              ios_base::openmode mode = ios_base::out); // C++17
130
131    void close();
132};
133
134template <class charT, class traits>
135  void
136  swap(basic_ofstream<charT, traits>& x, basic_ofstream<charT, traits>& y);
137
138typedef basic_ofstream<char>    ofstream;
139typedef basic_ofstream<wchar_t> wofstream;
140
141template <class charT, class traits=char_traits<charT> >
142class basic_fstream
143    : public basic_iostream<charT,traits>
144{
145public:
146    typedef charT                          char_type;
147    typedef traits                         traits_type;
148    typedef typename traits_type::int_type int_type;
149    typedef typename traits_type::pos_type pos_type;
150    typedef typename traits_type::off_type off_type;
151
152    basic_fstream();
153    explicit basic_fstream(const char* s, ios_base::openmode mode = ios_base::in|ios_base::out);
154    explicit basic_fstream(const string& s, ios_base::openmode mode = ios_base::in|ios_base::out);
155    explicit basic_fstream(const filesystem::path& p,
156                           ios_base::openmode mode = ios_base::in|ios_base::out); C++17
157    basic_fstream(basic_fstream&& rhs);
158
159    basic_fstream& operator=(basic_fstream&& rhs);
160    void swap(basic_fstream& rhs);
161
162    basic_filebuf<char_type, traits_type>* rdbuf() const;
163    bool is_open() const;
164    void open(const char* s, ios_base::openmode mode = ios_base::in|ios_base::out);
165    void open(const string& s, ios_base::openmode mode = ios_base::in|ios_base::out);
166    void open(const filesystem::path& s,
167              ios_base::openmode mode = ios_base::in|ios_base::out); // C++17
168
169    void close();
170};
171
172template <class charT, class traits>
173  void swap(basic_fstream<charT, traits>& x, basic_fstream<charT, traits>& y);
174
175typedef basic_fstream<char>    fstream;
176typedef basic_fstream<wchar_t> wfstream;
177
178}  // std
179
180*/
181
182#include <__algorithm/max.h>
183#include <__assert> // all public C++ headers provide the assertion handler
184#include <__availability>
185#include <__config>
186#include <__fwd/fstream.h>
187#include <__locale>
188#include <__utility/move.h>
189#include <__utility/swap.h>
190#include <__utility/unreachable.h>
191#include <cstdio>
192#include <filesystem>
193#include <istream>
194#include <ostream>
195#include <typeinfo>
196#include <version>
197
198#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
199#  pragma GCC system_header
200#endif
201
202_LIBCPP_PUSH_MACROS
203#include <__undef_macros>
204
205#if defined(_LIBCPP_MSVCRT) || defined(_NEWLIB_VERSION)
206#  define _LIBCPP_HAS_NO_OFF_T_FUNCTIONS
207#endif
208
209#if !defined(_LIBCPP_HAS_NO_FILESYSTEM)
210
211_LIBCPP_BEGIN_NAMESPACE_STD
212
213template <class _CharT, class _Traits>
214class _LIBCPP_TEMPLATE_VIS basic_filebuf : public basic_streambuf<_CharT, _Traits> {
215public:
216  typedef _CharT char_type;
217  typedef _Traits traits_type;
218  typedef typename traits_type::int_type int_type;
219  typedef typename traits_type::pos_type pos_type;
220  typedef typename traits_type::off_type off_type;
221  typedef typename traits_type::state_type state_type;
222
223  // 27.9.1.2 Constructors/destructor:
224  basic_filebuf();
225  basic_filebuf(basic_filebuf&& __rhs);
226  ~basic_filebuf() override;
227
228  // 27.9.1.3 Assign/swap:
229  _LIBCPP_HIDE_FROM_ABI basic_filebuf& operator=(basic_filebuf&& __rhs);
230  void swap(basic_filebuf& __rhs);
231
232  // 27.9.1.4 Members:
233  _LIBCPP_HIDE_FROM_ABI bool is_open() const;
234  basic_filebuf* open(const char* __s, ios_base::openmode __mode);
235#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
236  basic_filebuf* open(const wchar_t* __s, ios_base::openmode __mode);
237#  endif
238  _LIBCPP_HIDE_FROM_ABI basic_filebuf* open(const string& __s, ios_base::openmode __mode);
239
240#  if _LIBCPP_STD_VER >= 17
241  _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI basic_filebuf*
242  open(const filesystem::path& __p, ios_base::openmode __mode) {
243    return open(__p.c_str(), __mode);
244  }
245#  endif
246  _LIBCPP_HIDE_FROM_ABI basic_filebuf* __open(int __fd, ios_base::openmode __mode);
247  basic_filebuf* close();
248
249  _LIBCPP_HIDE_FROM_ABI inline static const char* __make_mdstring(ios_base::openmode __mode) _NOEXCEPT;
250
251protected:
252  // 27.9.1.5 Overridden virtual functions:
253  int_type underflow() override;
254  int_type pbackfail(int_type __c = traits_type::eof()) override;
255  int_type overflow(int_type __c = traits_type::eof()) override;
256  basic_streambuf<char_type, traits_type>* setbuf(char_type* __s, streamsize __n) override;
257  pos_type
258  seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __wch = ios_base::in | ios_base::out) override;
259  pos_type seekpos(pos_type __sp, ios_base::openmode __wch = ios_base::in | ios_base::out) override;
260  int sync() override;
261  void imbue(const locale& __loc) override;
262
263private:
264  char* __extbuf_;
265  const char* __extbufnext_;
266  const char* __extbufend_;
267  char __extbuf_min_[8];
268  size_t __ebs_;
269  char_type* __intbuf_;
270  size_t __ibs_;
271  FILE* __file_;
272  const codecvt<char_type, char, state_type>* __cv_;
273  state_type __st_;
274  state_type __st_last_;
275  ios_base::openmode __om_;
276  ios_base::openmode __cm_;
277  bool __owns_eb_;
278  bool __owns_ib_;
279  bool __always_noconv_;
280
281  bool __read_mode();
282  void __write_mode();
283
284  _LIBCPP_EXPORTED_FROM_ABI friend FILE* __get_ostream_file(ostream&);
285};
286
287template <class _CharT, class _Traits>
288basic_filebuf<_CharT, _Traits>::basic_filebuf()
289    : __extbuf_(nullptr),
290      __extbufnext_(nullptr),
291      __extbufend_(nullptr),
292      __ebs_(0),
293      __intbuf_(nullptr),
294      __ibs_(0),
295      __file_(nullptr),
296      __cv_(nullptr),
297      __st_(),
298      __st_last_(),
299      __om_(0),
300      __cm_(0),
301      __owns_eb_(false),
302      __owns_ib_(false),
303      __always_noconv_(false) {
304  if (std::has_facet<codecvt<char_type, char, state_type> >(this->getloc())) {
305    __cv_            = &std::use_facet<codecvt<char_type, char, state_type> >(this->getloc());
306    __always_noconv_ = __cv_->always_noconv();
307  }
308  setbuf(nullptr, 4096);
309}
310
311template <class _CharT, class _Traits>
312basic_filebuf<_CharT, _Traits>::basic_filebuf(basic_filebuf&& __rhs) : basic_streambuf<_CharT, _Traits>(__rhs) {
313  if (__rhs.__extbuf_ == __rhs.__extbuf_min_) {
314    __extbuf_     = __extbuf_min_;
315    __extbufnext_ = __extbuf_ + (__rhs.__extbufnext_ - __rhs.__extbuf_);
316    __extbufend_  = __extbuf_ + (__rhs.__extbufend_ - __rhs.__extbuf_);
317  } else {
318    __extbuf_     = __rhs.__extbuf_;
319    __extbufnext_ = __rhs.__extbufnext_;
320    __extbufend_  = __rhs.__extbufend_;
321  }
322  __ebs_           = __rhs.__ebs_;
323  __intbuf_        = __rhs.__intbuf_;
324  __ibs_           = __rhs.__ibs_;
325  __file_          = __rhs.__file_;
326  __cv_            = __rhs.__cv_;
327  __st_            = __rhs.__st_;
328  __st_last_       = __rhs.__st_last_;
329  __om_            = __rhs.__om_;
330  __cm_            = __rhs.__cm_;
331  __owns_eb_       = __rhs.__owns_eb_;
332  __owns_ib_       = __rhs.__owns_ib_;
333  __always_noconv_ = __rhs.__always_noconv_;
334  if (__rhs.pbase()) {
335    if (__rhs.pbase() == __rhs.__intbuf_)
336      this->setp(__intbuf_, __intbuf_ + (__rhs.epptr() - __rhs.pbase()));
337    else
338      this->setp((char_type*)__extbuf_, (char_type*)__extbuf_ + (__rhs.epptr() - __rhs.pbase()));
339    this->__pbump(__rhs.pptr() - __rhs.pbase());
340  } else if (__rhs.eback()) {
341    if (__rhs.eback() == __rhs.__intbuf_)
342      this->setg(__intbuf_, __intbuf_ + (__rhs.gptr() - __rhs.eback()), __intbuf_ + (__rhs.egptr() - __rhs.eback()));
343    else
344      this->setg((char_type*)__extbuf_,
345                 (char_type*)__extbuf_ + (__rhs.gptr() - __rhs.eback()),
346                 (char_type*)__extbuf_ + (__rhs.egptr() - __rhs.eback()));
347  }
348  __rhs.__extbuf_     = nullptr;
349  __rhs.__extbufnext_ = nullptr;
350  __rhs.__extbufend_  = nullptr;
351  __rhs.__ebs_        = 0;
352  __rhs.__intbuf_     = 0;
353  __rhs.__ibs_        = 0;
354  __rhs.__file_       = nullptr;
355  __rhs.__st_         = state_type();
356  __rhs.__st_last_    = state_type();
357  __rhs.__om_         = 0;
358  __rhs.__cm_         = 0;
359  __rhs.__owns_eb_    = false;
360  __rhs.__owns_ib_    = false;
361  __rhs.setg(0, 0, 0);
362  __rhs.setp(0, 0);
363}
364
365template <class _CharT, class _Traits>
366inline basic_filebuf<_CharT, _Traits>& basic_filebuf<_CharT, _Traits>::operator=(basic_filebuf&& __rhs) {
367  close();
368  swap(__rhs);
369  return *this;
370}
371
372template <class _CharT, class _Traits>
373basic_filebuf<_CharT, _Traits>::~basic_filebuf() {
374#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
375  try {
376#  endif // _LIBCPP_HAS_NO_EXCEPTIONS
377    close();
378#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
379  } catch (...) {
380  }
381#  endif // _LIBCPP_HAS_NO_EXCEPTIONS
382  if (__owns_eb_)
383    delete[] __extbuf_;
384  if (__owns_ib_)
385    delete[] __intbuf_;
386}
387
388template <class _CharT, class _Traits>
389void basic_filebuf<_CharT, _Traits>::swap(basic_filebuf& __rhs) {
390  basic_streambuf<char_type, traits_type>::swap(__rhs);
391  if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_) {
392    // Neither *this nor __rhs uses the small buffer, so we can simply swap the pointers.
393    std::swap(__extbuf_, __rhs.__extbuf_);
394    std::swap(__extbufnext_, __rhs.__extbufnext_);
395    std::swap(__extbufend_, __rhs.__extbufend_);
396  } else {
397    ptrdiff_t __ln = __extbufnext_ ? __extbufnext_ - __extbuf_ : 0;
398    ptrdiff_t __le = __extbufend_ ? __extbufend_ - __extbuf_ : 0;
399    ptrdiff_t __rn = __rhs.__extbufnext_ ? __rhs.__extbufnext_ - __rhs.__extbuf_ : 0;
400    ptrdiff_t __re = __rhs.__extbufend_ ? __rhs.__extbufend_ - __rhs.__extbuf_ : 0;
401    if (__extbuf_ == __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_) {
402      // *this uses the small buffer, but __rhs doesn't.
403      __extbuf_       = __rhs.__extbuf_;
404      __rhs.__extbuf_ = __rhs.__extbuf_min_;
405      std::memmove(__rhs.__extbuf_min_, __extbuf_min_, sizeof(__extbuf_min_));
406    } else if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ == __rhs.__extbuf_min_) {
407      // *this doesn't use the small buffer, but __rhs does.
408      __rhs.__extbuf_ = __extbuf_;
409      __extbuf_       = __extbuf_min_;
410      std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));
411    } else {
412      // Both *this and __rhs use the small buffer.
413      char __tmp[sizeof(__extbuf_min_)];
414      std::memmove(__tmp, __extbuf_min_, sizeof(__extbuf_min_));
415      std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));
416      std::memmove(__rhs.__extbuf_min_, __tmp, sizeof(__extbuf_min_));
417    }
418    __extbufnext_       = __extbuf_ + __rn;
419    __extbufend_        = __extbuf_ + __re;
420    __rhs.__extbufnext_ = __rhs.__extbuf_ + __ln;
421    __rhs.__extbufend_  = __rhs.__extbuf_ + __le;
422  }
423  std::swap(__ebs_, __rhs.__ebs_);
424  std::swap(__intbuf_, __rhs.__intbuf_);
425  std::swap(__ibs_, __rhs.__ibs_);
426  std::swap(__file_, __rhs.__file_);
427  std::swap(__cv_, __rhs.__cv_);
428  std::swap(__st_, __rhs.__st_);
429  std::swap(__st_last_, __rhs.__st_last_);
430  std::swap(__om_, __rhs.__om_);
431  std::swap(__cm_, __rhs.__cm_);
432  std::swap(__owns_eb_, __rhs.__owns_eb_);
433  std::swap(__owns_ib_, __rhs.__owns_ib_);
434  std::swap(__always_noconv_, __rhs.__always_noconv_);
435  if (this->eback() == (char_type*)__rhs.__extbuf_min_) {
436    ptrdiff_t __n = this->gptr() - this->eback();
437    ptrdiff_t __e = this->egptr() - this->eback();
438    this->setg((char_type*)__extbuf_min_, (char_type*)__extbuf_min_ + __n, (char_type*)__extbuf_min_ + __e);
439  } else if (this->pbase() == (char_type*)__rhs.__extbuf_min_) {
440    ptrdiff_t __n = this->pptr() - this->pbase();
441    ptrdiff_t __e = this->epptr() - this->pbase();
442    this->setp((char_type*)__extbuf_min_, (char_type*)__extbuf_min_ + __e);
443    this->__pbump(__n);
444  }
445  if (__rhs.eback() == (char_type*)__extbuf_min_) {
446    ptrdiff_t __n = __rhs.gptr() - __rhs.eback();
447    ptrdiff_t __e = __rhs.egptr() - __rhs.eback();
448    __rhs.setg(
449        (char_type*)__rhs.__extbuf_min_, (char_type*)__rhs.__extbuf_min_ + __n, (char_type*)__rhs.__extbuf_min_ + __e);
450  } else if (__rhs.pbase() == (char_type*)__extbuf_min_) {
451    ptrdiff_t __n = __rhs.pptr() - __rhs.pbase();
452    ptrdiff_t __e = __rhs.epptr() - __rhs.pbase();
453    __rhs.setp((char_type*)__rhs.__extbuf_min_, (char_type*)__rhs.__extbuf_min_ + __e);
454    __rhs.__pbump(__n);
455  }
456}
457
458template <class _CharT, class _Traits>
459inline _LIBCPP_HIDE_FROM_ABI void swap(basic_filebuf<_CharT, _Traits>& __x, basic_filebuf<_CharT, _Traits>& __y) {
460  __x.swap(__y);
461}
462
463template <class _CharT, class _Traits>
464inline bool basic_filebuf<_CharT, _Traits>::is_open() const {
465  return __file_ != nullptr;
466}
467
468template <class _CharT, class _Traits>
469const char* basic_filebuf<_CharT, _Traits>::__make_mdstring(ios_base::openmode __mode) _NOEXCEPT {
470  switch (__mode & ~ios_base::ate) {
471  case ios_base::out:
472  case ios_base::out | ios_base::trunc:
473    return "w" _LIBCPP_FOPEN_CLOEXEC_MODE;
474  case ios_base::out | ios_base::app:
475  case ios_base::app:
476    return "a" _LIBCPP_FOPEN_CLOEXEC_MODE;
477  case ios_base::in:
478    return "r" _LIBCPP_FOPEN_CLOEXEC_MODE;
479  case ios_base::in | ios_base::out:
480    return "r+" _LIBCPP_FOPEN_CLOEXEC_MODE;
481  case ios_base::in | ios_base::out | ios_base::trunc:
482    return "w+" _LIBCPP_FOPEN_CLOEXEC_MODE;
483  case ios_base::in | ios_base::out | ios_base::app:
484  case ios_base::in | ios_base::app:
485    return "a+" _LIBCPP_FOPEN_CLOEXEC_MODE;
486  case ios_base::out | ios_base::binary:
487  case ios_base::out | ios_base::trunc | ios_base::binary:
488    return "wb" _LIBCPP_FOPEN_CLOEXEC_MODE;
489  case ios_base::out | ios_base::app | ios_base::binary:
490  case ios_base::app | ios_base::binary:
491    return "ab" _LIBCPP_FOPEN_CLOEXEC_MODE;
492  case ios_base::in | ios_base::binary:
493    return "rb" _LIBCPP_FOPEN_CLOEXEC_MODE;
494  case ios_base::in | ios_base::out | ios_base::binary:
495    return "r+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
496  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
497    return "w+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
498  case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
499  case ios_base::in | ios_base::app | ios_base::binary:
500    return "a+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
501#  if _LIBCPP_STD_VER >= 23
502  case ios_base::out | ios_base::noreplace:
503  case ios_base::out | ios_base::trunc | ios_base::noreplace:
504    return "wx" _LIBCPP_FOPEN_CLOEXEC_MODE;
505  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:
506    return "w+x" _LIBCPP_FOPEN_CLOEXEC_MODE;
507  case ios_base::out | ios_base::binary | ios_base::noreplace:
508  case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
509    return "wbx" _LIBCPP_FOPEN_CLOEXEC_MODE;
510  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
511    return "w+bx" _LIBCPP_FOPEN_CLOEXEC_MODE;
512#  endif // _LIBCPP_STD_VER >= 23
513  default:
514    return nullptr;
515  }
516  __libcpp_unreachable();
517}
518
519template <class _CharT, class _Traits>
520basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
521  basic_filebuf<_CharT, _Traits>* __rt = nullptr;
522  if (__file_ == nullptr) {
523    if (const char* __mdstr = __make_mdstring(__mode)) {
524      __rt    = this;
525      __file_ = fopen(__s, __mdstr);
526      if (__file_) {
527        __om_ = __mode;
528        if (__mode & ios_base::ate) {
529          if (fseek(__file_, 0, SEEK_END)) {
530            fclose(__file_);
531            __file_ = nullptr;
532            __rt    = nullptr;
533          }
534        }
535      } else
536        __rt = nullptr;
537    }
538  }
539  return __rt;
540}
541
542template <class _CharT, class _Traits>
543inline basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
544  basic_filebuf<_CharT, _Traits>* __rt = nullptr;
545  if (__file_ == nullptr) {
546    if (const char* __mdstr = __make_mdstring(__mode)) {
547      __rt    = this;
548      __file_ = fdopen(__fd, __mdstr);
549      if (__file_) {
550        __om_ = __mode;
551        if (__mode & ios_base::ate) {
552          if (fseek(__file_, 0, SEEK_END)) {
553            fclose(__file_);
554            __file_ = nullptr;
555            __rt    = nullptr;
556          }
557        }
558      } else
559        __rt = nullptr;
560    }
561  }
562  return __rt;
563}
564
565#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
566// This is basically the same as the char* overload except that it uses _wfopen
567// and long mode strings.
568template <class _CharT, class _Traits>
569basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {
570  basic_filebuf<_CharT, _Traits>* __rt = nullptr;
571  if (__file_ == nullptr) {
572    __rt = this;
573    const wchar_t* __mdstr;
574    switch (__mode & ~ios_base::ate) {
575    case ios_base::out:
576    case ios_base::out | ios_base::trunc:
577      __mdstr = L"w";
578      break;
579    case ios_base::out | ios_base::app:
580    case ios_base::app:
581      __mdstr = L"a";
582      break;
583    case ios_base::in:
584      __mdstr = L"r";
585      break;
586    case ios_base::in | ios_base::out:
587      __mdstr = L"r+";
588      break;
589    case ios_base::in | ios_base::out | ios_base::trunc:
590      __mdstr = L"w+";
591      break;
592    case ios_base::in | ios_base::out | ios_base::app:
593    case ios_base::in | ios_base::app:
594      __mdstr = L"a+";
595      break;
596    case ios_base::out | ios_base::binary:
597    case ios_base::out | ios_base::trunc | ios_base::binary:
598      __mdstr = L"wb";
599      break;
600    case ios_base::out | ios_base::app | ios_base::binary:
601    case ios_base::app | ios_base::binary:
602      __mdstr = L"ab";
603      break;
604    case ios_base::in | ios_base::binary:
605      __mdstr = L"rb";
606      break;
607    case ios_base::in | ios_base::out | ios_base::binary:
608      __mdstr = L"r+b";
609      break;
610    case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
611      __mdstr = L"w+b";
612      break;
613    case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
614    case ios_base::in | ios_base::app | ios_base::binary:
615      __mdstr = L"a+b";
616      break;
617#    if _LIBCPP_STD_VER >= 23
618    case ios_base::out | ios_base::noreplace:
619    case ios_base::out | ios_base::trunc | ios_base::noreplace:
620      __mdstr = L"wx";
621      break;
622    case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:
623      __mdstr = L"w+x";
624      break;
625    case ios_base::out | ios_base::binary | ios_base::noreplace:
626    case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
627      __mdstr = L"wbx";
628      break;
629    case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
630      __mdstr = L"w+bx";
631      break;
632#    endif // _LIBCPP_STD_VER >= 23
633    default:
634      __rt = nullptr;
635      break;
636    }
637    if (__rt) {
638      __file_ = _wfopen(__s, __mdstr);
639      if (__file_) {
640        __om_ = __mode;
641        if (__mode & ios_base::ate) {
642          if (fseek(__file_, 0, SEEK_END)) {
643            fclose(__file_);
644            __file_ = nullptr;
645            __rt    = nullptr;
646          }
647        }
648      } else
649        __rt = nullptr;
650    }
651  }
652  return __rt;
653}
654#  endif
655
656template <class _CharT, class _Traits>
657inline basic_filebuf<_CharT, _Traits>*
658basic_filebuf<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {
659  return open(__s.c_str(), __mode);
660}
661
662template <class _CharT, class _Traits>
663basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::close() {
664  basic_filebuf<_CharT, _Traits>* __rt = nullptr;
665  if (__file_) {
666    __rt = this;
667    unique_ptr<FILE, int (*)(FILE*)> __h(__file_, fclose);
668    if (sync())
669      __rt = nullptr;
670    if (fclose(__h.release()))
671      __rt = nullptr;
672    __file_ = nullptr;
673    setbuf(0, 0);
674  }
675  return __rt;
676}
677
678template <class _CharT, class _Traits>
679typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::underflow() {
680  if (__file_ == nullptr)
681    return traits_type::eof();
682  bool __initial = __read_mode();
683  char_type __1buf;
684  if (this->gptr() == nullptr)
685    this->setg(&__1buf, &__1buf + 1, &__1buf + 1);
686  const size_t __unget_sz = __initial ? 0 : std::min<size_t>((this->egptr() - this->eback()) / 2, 4);
687  int_type __c            = traits_type::eof();
688  if (this->gptr() == this->egptr()) {
689    std::memmove(this->eback(), this->egptr() - __unget_sz, __unget_sz * sizeof(char_type));
690    if (__always_noconv_) {
691      size_t __nmemb = static_cast<size_t>(this->egptr() - this->eback() - __unget_sz);
692      __nmemb        = ::fread(this->eback() + __unget_sz, 1, __nmemb, __file_);
693      if (__nmemb != 0) {
694        this->setg(this->eback(), this->eback() + __unget_sz, this->eback() + __unget_sz + __nmemb);
695        __c = traits_type::to_int_type(*this->gptr());
696      }
697    } else {
698      if (__extbufend_ != __extbufnext_) {
699        _LIBCPP_ASSERT_NON_NULL(__extbufnext_ != nullptr, "underflow moving from nullptr");
700        _LIBCPP_ASSERT_NON_NULL(__extbuf_ != nullptr, "underflow moving into nullptr");
701        std::memmove(__extbuf_, __extbufnext_, __extbufend_ - __extbufnext_);
702      }
703      __extbufnext_ = __extbuf_ + (__extbufend_ - __extbufnext_);
704      __extbufend_  = __extbuf_ + (__extbuf_ == __extbuf_min_ ? sizeof(__extbuf_min_) : __ebs_);
705      size_t __nmemb =
706          std::min(static_cast<size_t>(__ibs_ - __unget_sz), static_cast<size_t>(__extbufend_ - __extbufnext_));
707      codecvt_base::result __r;
708      __st_last_  = __st_;
709      size_t __nr = fread((void*)const_cast<char*>(__extbufnext_), 1, __nmemb, __file_);
710      if (__nr != 0) {
711        if (!__cv_)
712          __throw_bad_cast();
713
714        __extbufend_ = __extbufnext_ + __nr;
715        char_type* __inext;
716        __r = __cv_->in(
717            __st_, __extbuf_, __extbufend_, __extbufnext_, this->eback() + __unget_sz, this->eback() + __ibs_, __inext);
718        if (__r == codecvt_base::noconv) {
719          this->setg((char_type*)__extbuf_, (char_type*)__extbuf_, (char_type*)const_cast<char*>(__extbufend_));
720          __c = traits_type::to_int_type(*this->gptr());
721        } else if (__inext != this->eback() + __unget_sz) {
722          this->setg(this->eback(), this->eback() + __unget_sz, __inext);
723          __c = traits_type::to_int_type(*this->gptr());
724        }
725      }
726    }
727  } else
728    __c = traits_type::to_int_type(*this->gptr());
729  if (this->eback() == &__1buf)
730    this->setg(nullptr, nullptr, nullptr);
731  return __c;
732}
733
734template <class _CharT, class _Traits>
735typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::pbackfail(int_type __c) {
736  if (__file_ && this->eback() < this->gptr()) {
737    if (traits_type::eq_int_type(__c, traits_type::eof())) {
738      this->gbump(-1);
739      return traits_type::not_eof(__c);
740    }
741    if ((__om_ & ios_base::out) || traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1])) {
742      this->gbump(-1);
743      *this->gptr() = traits_type::to_char_type(__c);
744      return __c;
745    }
746  }
747  return traits_type::eof();
748}
749
750template <class _CharT, class _Traits>
751typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::overflow(int_type __c) {
752  if (__file_ == nullptr)
753    return traits_type::eof();
754  __write_mode();
755  char_type __1buf;
756  char_type* __pb_save  = this->pbase();
757  char_type* __epb_save = this->epptr();
758  if (!traits_type::eq_int_type(__c, traits_type::eof())) {
759    if (this->pptr() == nullptr)
760      this->setp(&__1buf, &__1buf + 1);
761    *this->pptr() = traits_type::to_char_type(__c);
762    this->pbump(1);
763  }
764  if (this->pptr() != this->pbase()) {
765    if (__always_noconv_) {
766      size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
767      if (std::fwrite(this->pbase(), sizeof(char_type), __nmemb, __file_) != __nmemb)
768        return traits_type::eof();
769    } else {
770      char* __extbe = __extbuf_;
771      codecvt_base::result __r;
772      do {
773        if (!__cv_)
774          __throw_bad_cast();
775
776        const char_type* __e;
777        __r = __cv_->out(__st_, this->pbase(), this->pptr(), __e, __extbuf_, __extbuf_ + __ebs_, __extbe);
778        if (__e == this->pbase())
779          return traits_type::eof();
780        if (__r == codecvt_base::noconv) {
781          size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
782          if (std::fwrite(this->pbase(), 1, __nmemb, __file_) != __nmemb)
783            return traits_type::eof();
784        } else if (__r == codecvt_base::ok || __r == codecvt_base::partial) {
785          size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
786          if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
787            return traits_type::eof();
788          if (__r == codecvt_base::partial) {
789            this->setp(const_cast<char_type*>(__e), this->pptr());
790            this->__pbump(this->epptr() - this->pbase());
791          }
792        } else
793          return traits_type::eof();
794      } while (__r == codecvt_base::partial);
795    }
796    this->setp(__pb_save, __epb_save);
797  }
798  return traits_type::not_eof(__c);
799}
800
801template <class _CharT, class _Traits>
802basic_streambuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::setbuf(char_type* __s, streamsize __n) {
803  this->setg(nullptr, nullptr, nullptr);
804  this->setp(nullptr, nullptr);
805  if (__owns_eb_)
806    delete[] __extbuf_;
807  if (__owns_ib_)
808    delete[] __intbuf_;
809  __ebs_ = __n;
810  if (__ebs_ > sizeof(__extbuf_min_)) {
811    if (__always_noconv_ && __s) {
812      __extbuf_  = (char*)__s;
813      __owns_eb_ = false;
814    } else {
815      __extbuf_  = new char[__ebs_];
816      __owns_eb_ = true;
817    }
818  } else {
819    __extbuf_  = __extbuf_min_;
820    __ebs_     = sizeof(__extbuf_min_);
821    __owns_eb_ = false;
822  }
823  if (!__always_noconv_) {
824    __ibs_ = max<streamsize>(__n, sizeof(__extbuf_min_));
825    if (__s && __ibs_ > sizeof(__extbuf_min_)) {
826      __intbuf_  = __s;
827      __owns_ib_ = false;
828    } else {
829      __intbuf_  = new char_type[__ibs_];
830      __owns_ib_ = true;
831    }
832  } else {
833    __ibs_     = 0;
834    __intbuf_  = nullptr;
835    __owns_ib_ = false;
836  }
837  return this;
838}
839
840template <class _CharT, class _Traits>
841typename basic_filebuf<_CharT, _Traits>::pos_type
842basic_filebuf<_CharT, _Traits>::seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode) {
843  if (!__cv_)
844    __throw_bad_cast();
845
846  int __width = __cv_->encoding();
847  if (__file_ == nullptr || (__width <= 0 && __off != 0) || sync())
848    return pos_type(off_type(-1));
849  // __width > 0 || __off == 0
850  int __whence;
851  switch (__way) {
852  case ios_base::beg:
853    __whence = SEEK_SET;
854    break;
855  case ios_base::cur:
856    __whence = SEEK_CUR;
857    break;
858  case ios_base::end:
859    __whence = SEEK_END;
860    break;
861  default:
862    return pos_type(off_type(-1));
863  }
864#  if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
865  if (fseek(__file_, __width > 0 ? __width * __off : 0, __whence))
866    return pos_type(off_type(-1));
867  pos_type __r = ftell(__file_);
868#  else
869  if (::fseeko(__file_, __width > 0 ? __width * __off : 0, __whence))
870    return pos_type(off_type(-1));
871  pos_type __r = ftello(__file_);
872#  endif
873  __r.state(__st_);
874  return __r;
875}
876
877template <class _CharT, class _Traits>
878typename basic_filebuf<_CharT, _Traits>::pos_type
879basic_filebuf<_CharT, _Traits>::seekpos(pos_type __sp, ios_base::openmode) {
880  if (__file_ == nullptr || sync())
881    return pos_type(off_type(-1));
882#  if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
883  if (fseek(__file_, __sp, SEEK_SET))
884    return pos_type(off_type(-1));
885#  else
886  if (::fseeko(__file_, __sp, SEEK_SET))
887    return pos_type(off_type(-1));
888#  endif
889  __st_ = __sp.state();
890  return __sp;
891}
892
893template <class _CharT, class _Traits>
894int basic_filebuf<_CharT, _Traits>::sync() {
895  if (__file_ == nullptr)
896    return 0;
897  if (!__cv_)
898    __throw_bad_cast();
899
900  if (__cm_ & ios_base::out) {
901    if (this->pptr() != this->pbase())
902      if (overflow() == traits_type::eof())
903        return -1;
904    codecvt_base::result __r;
905    do {
906      char* __extbe;
907      __r            = __cv_->unshift(__st_, __extbuf_, __extbuf_ + __ebs_, __extbe);
908      size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
909      if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
910        return -1;
911    } while (__r == codecvt_base::partial);
912    if (__r == codecvt_base::error)
913      return -1;
914    if (fflush(__file_))
915      return -1;
916  } else if (__cm_ & ios_base::in) {
917    off_type __c;
918    state_type __state = __st_last_;
919    bool __update_st   = false;
920    if (__always_noconv_)
921      __c = this->egptr() - this->gptr();
922    else {
923      int __width = __cv_->encoding();
924      __c         = __extbufend_ - __extbufnext_;
925      if (__width > 0)
926        __c += __width * (this->egptr() - this->gptr());
927      else {
928        if (this->gptr() != this->egptr()) {
929          const int __off = __cv_->length(__state, __extbuf_, __extbufnext_, this->gptr() - this->eback());
930          __c += __extbufnext_ - __extbuf_ - __off;
931          __update_st = true;
932        }
933      }
934    }
935#  if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
936    if (fseek(__file_, -__c, SEEK_CUR))
937      return -1;
938#  else
939    if (::fseeko(__file_, -__c, SEEK_CUR))
940      return -1;
941#  endif
942    if (__update_st)
943      __st_ = __state;
944    __extbufnext_ = __extbufend_ = __extbuf_;
945    this->setg(nullptr, nullptr, nullptr);
946    __cm_ = 0;
947  }
948  return 0;
949}
950
951template <class _CharT, class _Traits>
952void basic_filebuf<_CharT, _Traits>::imbue(const locale& __loc) {
953  sync();
954  __cv_            = &std::use_facet<codecvt<char_type, char, state_type> >(__loc);
955  bool __old_anc   = __always_noconv_;
956  __always_noconv_ = __cv_->always_noconv();
957  if (__old_anc != __always_noconv_) {
958    this->setg(nullptr, nullptr, nullptr);
959    this->setp(nullptr, nullptr);
960    // invariant, char_type is char, else we couldn't get here
961    if (__always_noconv_) // need to dump __intbuf_
962    {
963      if (__owns_eb_)
964        delete[] __extbuf_;
965      __owns_eb_ = __owns_ib_;
966      __ebs_     = __ibs_;
967      __extbuf_  = (char*)__intbuf_;
968      __ibs_     = 0;
969      __intbuf_  = nullptr;
970      __owns_ib_ = false;
971    } else // need to obtain an __intbuf_.
972    {      // If __extbuf_ is user-supplied, use it, else new __intbuf_
973      if (!__owns_eb_ && __extbuf_ != __extbuf_min_) {
974        __ibs_     = __ebs_;
975        __intbuf_  = (char_type*)__extbuf_;
976        __owns_ib_ = false;
977        __extbuf_  = new char[__ebs_];
978        __owns_eb_ = true;
979      } else {
980        __ibs_     = __ebs_;
981        __intbuf_  = new char_type[__ibs_];
982        __owns_ib_ = true;
983      }
984    }
985  }
986}
987
988template <class _CharT, class _Traits>
989bool basic_filebuf<_CharT, _Traits>::__read_mode() {
990  if (!(__cm_ & ios_base::in)) {
991    this->setp(nullptr, nullptr);
992    if (__always_noconv_)
993      this->setg((char_type*)__extbuf_, (char_type*)__extbuf_ + __ebs_, (char_type*)__extbuf_ + __ebs_);
994    else
995      this->setg(__intbuf_, __intbuf_ + __ibs_, __intbuf_ + __ibs_);
996    __cm_ = ios_base::in;
997    return true;
998  }
999  return false;
1000}
1001
1002template <class _CharT, class _Traits>
1003void basic_filebuf<_CharT, _Traits>::__write_mode() {
1004  if (!(__cm_ & ios_base::out)) {
1005    this->setg(nullptr, nullptr, nullptr);
1006    if (__ebs_ > sizeof(__extbuf_min_)) {
1007      if (__always_noconv_)
1008        this->setp((char_type*)__extbuf_, (char_type*)__extbuf_ + (__ebs_ - 1));
1009      else
1010        this->setp(__intbuf_, __intbuf_ + (__ibs_ - 1));
1011    } else
1012      this->setp(nullptr, nullptr);
1013    __cm_ = ios_base::out;
1014  }
1015}
1016
1017// basic_ifstream
1018
1019template <class _CharT, class _Traits>
1020class _LIBCPP_TEMPLATE_VIS basic_ifstream : public basic_istream<_CharT, _Traits> {
1021public:
1022  typedef _CharT char_type;
1023  typedef _Traits traits_type;
1024  typedef typename traits_type::int_type int_type;
1025  typedef typename traits_type::pos_type pos_type;
1026  typedef typename traits_type::off_type off_type;
1027
1028  _LIBCPP_HIDE_FROM_ABI basic_ifstream();
1029  _LIBCPP_HIDE_FROM_ABI explicit basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in);
1030#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1031  _LIBCPP_HIDE_FROM_ABI explicit basic_ifstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
1032#  endif
1033  _LIBCPP_HIDE_FROM_ABI explicit basic_ifstream(const string& __s, ios_base::openmode __mode = ios_base::in);
1034#  if _LIBCPP_STD_VER >= 17
1035  _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI explicit basic_ifstream(
1036      const filesystem::path& __p, ios_base::openmode __mode = ios_base::in)
1037      : basic_ifstream(__p.c_str(), __mode) {}
1038#  endif // _LIBCPP_STD_VER >= 17
1039  _LIBCPP_HIDE_FROM_ABI basic_ifstream(basic_ifstream&& __rhs);
1040  _LIBCPP_HIDE_FROM_ABI basic_ifstream& operator=(basic_ifstream&& __rhs);
1041  _LIBCPP_HIDE_FROM_ABI void swap(basic_ifstream& __rhs);
1042
1043  _LIBCPP_HIDE_FROM_ABI basic_filebuf<char_type, traits_type>* rdbuf() const;
1044  _LIBCPP_HIDE_FROM_ABI bool is_open() const;
1045  void open(const char* __s, ios_base::openmode __mode = ios_base::in);
1046#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1047  void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
1048#  endif
1049  void open(const string& __s, ios_base::openmode __mode = ios_base::in);
1050#  if _LIBCPP_STD_VER >= 17
1051  _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI void
1052  open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in) {
1053    return open(__p.c_str(), __mode);
1054  }
1055#  endif // _LIBCPP_STD_VER >= 17
1056
1057  _LIBCPP_HIDE_FROM_ABI void __open(int __fd, ios_base::openmode __mode);
1058  _LIBCPP_HIDE_FROM_ABI void close();
1059
1060private:
1061  basic_filebuf<char_type, traits_type> __sb_;
1062};
1063
1064template <class _CharT, class _Traits>
1065inline basic_ifstream<_CharT, _Traits>::basic_ifstream() : basic_istream<char_type, traits_type>(&__sb_) {}
1066
1067template <class _CharT, class _Traits>
1068inline basic_ifstream<_CharT, _Traits>::basic_ifstream(const char* __s, ios_base::openmode __mode)
1069    : basic_istream<char_type, traits_type>(&__sb_) {
1070  if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1071    this->setstate(ios_base::failbit);
1072}
1073
1074#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1075template <class _CharT, class _Traits>
1076inline basic_ifstream<_CharT, _Traits>::basic_ifstream(const wchar_t* __s, ios_base::openmode __mode)
1077    : basic_istream<char_type, traits_type>(&__sb_) {
1078  if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1079    this->setstate(ios_base::failbit);
1080}
1081#  endif
1082
1083template <class _CharT, class _Traits>
1084inline basic_ifstream<_CharT, _Traits>::basic_ifstream(const string& __s, ios_base::openmode __mode)
1085    : basic_istream<char_type, traits_type>(&__sb_) {
1086  if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1087    this->setstate(ios_base::failbit);
1088}
1089
1090template <class _CharT, class _Traits>
1091inline basic_ifstream<_CharT, _Traits>::basic_ifstream(basic_ifstream&& __rhs)
1092    : basic_istream<char_type, traits_type>(std::move(__rhs)), __sb_(std::move(__rhs.__sb_)) {
1093  this->set_rdbuf(&__sb_);
1094}
1095
1096template <class _CharT, class _Traits>
1097inline basic_ifstream<_CharT, _Traits>& basic_ifstream<_CharT, _Traits>::operator=(basic_ifstream&& __rhs) {
1098  basic_istream<char_type, traits_type>::operator=(std::move(__rhs));
1099  __sb_ = std::move(__rhs.__sb_);
1100  return *this;
1101}
1102
1103template <class _CharT, class _Traits>
1104inline void basic_ifstream<_CharT, _Traits>::swap(basic_ifstream& __rhs) {
1105  basic_istream<char_type, traits_type>::swap(__rhs);
1106  __sb_.swap(__rhs.__sb_);
1107}
1108
1109template <class _CharT, class _Traits>
1110inline _LIBCPP_HIDE_FROM_ABI void swap(basic_ifstream<_CharT, _Traits>& __x, basic_ifstream<_CharT, _Traits>& __y) {
1111  __x.swap(__y);
1112}
1113
1114template <class _CharT, class _Traits>
1115inline basic_filebuf<_CharT, _Traits>* basic_ifstream<_CharT, _Traits>::rdbuf() const {
1116  return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1117}
1118
1119template <class _CharT, class _Traits>
1120inline bool basic_ifstream<_CharT, _Traits>::is_open() const {
1121  return __sb_.is_open();
1122}
1123
1124template <class _CharT, class _Traits>
1125void basic_ifstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
1126  if (__sb_.open(__s, __mode | ios_base::in))
1127    this->clear();
1128  else
1129    this->setstate(ios_base::failbit);
1130}
1131
1132#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1133template <class _CharT, class _Traits>
1134void basic_ifstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {
1135  if (__sb_.open(__s, __mode | ios_base::in))
1136    this->clear();
1137  else
1138    this->setstate(ios_base::failbit);
1139}
1140#  endif
1141
1142template <class _CharT, class _Traits>
1143void basic_ifstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {
1144  if (__sb_.open(__s, __mode | ios_base::in))
1145    this->clear();
1146  else
1147    this->setstate(ios_base::failbit);
1148}
1149
1150template <class _CharT, class _Traits>
1151inline void basic_ifstream<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
1152  if (__sb_.__open(__fd, __mode | ios_base::in))
1153    this->clear();
1154  else
1155    this->setstate(ios_base::failbit);
1156}
1157
1158template <class _CharT, class _Traits>
1159inline void basic_ifstream<_CharT, _Traits>::close() {
1160  if (__sb_.close() == 0)
1161    this->setstate(ios_base::failbit);
1162}
1163
1164// basic_ofstream
1165
1166template <class _CharT, class _Traits>
1167class _LIBCPP_TEMPLATE_VIS basic_ofstream : public basic_ostream<_CharT, _Traits> {
1168public:
1169  typedef _CharT char_type;
1170  typedef _Traits traits_type;
1171  typedef typename traits_type::int_type int_type;
1172  typedef typename traits_type::pos_type pos_type;
1173  typedef typename traits_type::off_type off_type;
1174
1175  _LIBCPP_HIDE_FROM_ABI basic_ofstream();
1176  _LIBCPP_HIDE_FROM_ABI explicit basic_ofstream(const char* __s, ios_base::openmode __mode = ios_base::out);
1177#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1178  _LIBCPP_HIDE_FROM_ABI explicit basic_ofstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
1179#  endif
1180  _LIBCPP_HIDE_FROM_ABI explicit basic_ofstream(const string& __s, ios_base::openmode __mode = ios_base::out);
1181
1182#  if _LIBCPP_STD_VER >= 17
1183  _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI explicit basic_ofstream(
1184      const filesystem::path& __p, ios_base::openmode __mode = ios_base::out)
1185      : basic_ofstream(__p.c_str(), __mode) {}
1186#  endif // _LIBCPP_STD_VER >= 17
1187
1188  _LIBCPP_HIDE_FROM_ABI basic_ofstream(basic_ofstream&& __rhs);
1189  _LIBCPP_HIDE_FROM_ABI basic_ofstream& operator=(basic_ofstream&& __rhs);
1190  _LIBCPP_HIDE_FROM_ABI void swap(basic_ofstream& __rhs);
1191
1192  _LIBCPP_HIDE_FROM_ABI basic_filebuf<char_type, traits_type>* rdbuf() const;
1193  _LIBCPP_HIDE_FROM_ABI bool is_open() const;
1194  void open(const char* __s, ios_base::openmode __mode = ios_base::out);
1195#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1196  void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
1197#  endif
1198  void open(const string& __s, ios_base::openmode __mode = ios_base::out);
1199
1200#  if _LIBCPP_STD_VER >= 17
1201  _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI void
1202  open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::out) {
1203    return open(__p.c_str(), __mode);
1204  }
1205#  endif // _LIBCPP_STD_VER >= 17
1206
1207  _LIBCPP_HIDE_FROM_ABI void __open(int __fd, ios_base::openmode __mode);
1208  _LIBCPP_HIDE_FROM_ABI void close();
1209
1210private:
1211  basic_filebuf<char_type, traits_type> __sb_;
1212};
1213
1214template <class _CharT, class _Traits>
1215inline basic_ofstream<_CharT, _Traits>::basic_ofstream() : basic_ostream<char_type, traits_type>(&__sb_) {}
1216
1217template <class _CharT, class _Traits>
1218inline basic_ofstream<_CharT, _Traits>::basic_ofstream(const char* __s, ios_base::openmode __mode)
1219    : basic_ostream<char_type, traits_type>(&__sb_) {
1220  if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1221    this->setstate(ios_base::failbit);
1222}
1223
1224#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1225template <class _CharT, class _Traits>
1226inline basic_ofstream<_CharT, _Traits>::basic_ofstream(const wchar_t* __s, ios_base::openmode __mode)
1227    : basic_ostream<char_type, traits_type>(&__sb_) {
1228  if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1229    this->setstate(ios_base::failbit);
1230}
1231#  endif
1232
1233template <class _CharT, class _Traits>
1234inline basic_ofstream<_CharT, _Traits>::basic_ofstream(const string& __s, ios_base::openmode __mode)
1235    : basic_ostream<char_type, traits_type>(&__sb_) {
1236  if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1237    this->setstate(ios_base::failbit);
1238}
1239
1240template <class _CharT, class _Traits>
1241inline basic_ofstream<_CharT, _Traits>::basic_ofstream(basic_ofstream&& __rhs)
1242    : basic_ostream<char_type, traits_type>(std::move(__rhs)), __sb_(std::move(__rhs.__sb_)) {
1243  this->set_rdbuf(&__sb_);
1244}
1245
1246template <class _CharT, class _Traits>
1247inline basic_ofstream<_CharT, _Traits>& basic_ofstream<_CharT, _Traits>::operator=(basic_ofstream&& __rhs) {
1248  basic_ostream<char_type, traits_type>::operator=(std::move(__rhs));
1249  __sb_ = std::move(__rhs.__sb_);
1250  return *this;
1251}
1252
1253template <class _CharT, class _Traits>
1254inline void basic_ofstream<_CharT, _Traits>::swap(basic_ofstream& __rhs) {
1255  basic_ostream<char_type, traits_type>::swap(__rhs);
1256  __sb_.swap(__rhs.__sb_);
1257}
1258
1259template <class _CharT, class _Traits>
1260inline _LIBCPP_HIDE_FROM_ABI void swap(basic_ofstream<_CharT, _Traits>& __x, basic_ofstream<_CharT, _Traits>& __y) {
1261  __x.swap(__y);
1262}
1263
1264template <class _CharT, class _Traits>
1265inline basic_filebuf<_CharT, _Traits>* basic_ofstream<_CharT, _Traits>::rdbuf() const {
1266  return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1267}
1268
1269template <class _CharT, class _Traits>
1270inline bool basic_ofstream<_CharT, _Traits>::is_open() const {
1271  return __sb_.is_open();
1272}
1273
1274template <class _CharT, class _Traits>
1275void basic_ofstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
1276  if (__sb_.open(__s, __mode | ios_base::out))
1277    this->clear();
1278  else
1279    this->setstate(ios_base::failbit);
1280}
1281
1282#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1283template <class _CharT, class _Traits>
1284void basic_ofstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {
1285  if (__sb_.open(__s, __mode | ios_base::out))
1286    this->clear();
1287  else
1288    this->setstate(ios_base::failbit);
1289}
1290#  endif
1291
1292template <class _CharT, class _Traits>
1293void basic_ofstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {
1294  if (__sb_.open(__s, __mode | ios_base::out))
1295    this->clear();
1296  else
1297    this->setstate(ios_base::failbit);
1298}
1299
1300template <class _CharT, class _Traits>
1301inline void basic_ofstream<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
1302  if (__sb_.__open(__fd, __mode | ios_base::out))
1303    this->clear();
1304  else
1305    this->setstate(ios_base::failbit);
1306}
1307
1308template <class _CharT, class _Traits>
1309inline void basic_ofstream<_CharT, _Traits>::close() {
1310  if (__sb_.close() == nullptr)
1311    this->setstate(ios_base::failbit);
1312}
1313
1314// basic_fstream
1315
1316template <class _CharT, class _Traits>
1317class _LIBCPP_TEMPLATE_VIS basic_fstream : public basic_iostream<_CharT, _Traits> {
1318public:
1319  typedef _CharT char_type;
1320  typedef _Traits traits_type;
1321  typedef typename traits_type::int_type int_type;
1322  typedef typename traits_type::pos_type pos_type;
1323  typedef typename traits_type::off_type off_type;
1324
1325  _LIBCPP_HIDE_FROM_ABI basic_fstream();
1326  _LIBCPP_HIDE_FROM_ABI explicit basic_fstream(const char* __s,
1327                                               ios_base::openmode __mode = ios_base::in | ios_base::out);
1328#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1329  _LIBCPP_HIDE_FROM_ABI explicit basic_fstream(const wchar_t* __s,
1330                                               ios_base::openmode __mode = ios_base::in | ios_base::out);
1331#  endif
1332  _LIBCPP_HIDE_FROM_ABI explicit basic_fstream(const string& __s,
1333                                               ios_base::openmode __mode = ios_base::in | ios_base::out);
1334
1335#  if _LIBCPP_STD_VER >= 17
1336  _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI explicit basic_fstream(
1337      const filesystem::path& __p, ios_base::openmode __mode = ios_base::in | ios_base::out)
1338      : basic_fstream(__p.c_str(), __mode) {}
1339#  endif // _LIBCPP_STD_VER >= 17
1340
1341  _LIBCPP_HIDE_FROM_ABI basic_fstream(basic_fstream&& __rhs);
1342
1343  _LIBCPP_HIDE_FROM_ABI basic_fstream& operator=(basic_fstream&& __rhs);
1344
1345  _LIBCPP_HIDE_FROM_ABI void swap(basic_fstream& __rhs);
1346
1347  _LIBCPP_HIDE_FROM_ABI basic_filebuf<char_type, traits_type>* rdbuf() const;
1348  _LIBCPP_HIDE_FROM_ABI bool is_open() const;
1349  _LIBCPP_HIDE_FROM_ABI void open(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1350#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1351  void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1352#  endif
1353  _LIBCPP_HIDE_FROM_ABI void open(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1354
1355#  if _LIBCPP_STD_VER >= 17
1356  _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI void
1357  open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in | ios_base::out) {
1358    return open(__p.c_str(), __mode);
1359  }
1360#  endif // _LIBCPP_STD_VER >= 17
1361
1362  _LIBCPP_HIDE_FROM_ABI void close();
1363
1364private:
1365  basic_filebuf<char_type, traits_type> __sb_;
1366};
1367
1368template <class _CharT, class _Traits>
1369inline basic_fstream<_CharT, _Traits>::basic_fstream() : basic_iostream<char_type, traits_type>(&__sb_) {}
1370
1371template <class _CharT, class _Traits>
1372inline basic_fstream<_CharT, _Traits>::basic_fstream(const char* __s, ios_base::openmode __mode)
1373    : basic_iostream<char_type, traits_type>(&__sb_) {
1374  if (__sb_.open(__s, __mode) == nullptr)
1375    this->setstate(ios_base::failbit);
1376}
1377
1378#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1379template <class _CharT, class _Traits>
1380inline basic_fstream<_CharT, _Traits>::basic_fstream(const wchar_t* __s, ios_base::openmode __mode)
1381    : basic_iostream<char_type, traits_type>(&__sb_) {
1382  if (__sb_.open(__s, __mode) == nullptr)
1383    this->setstate(ios_base::failbit);
1384}
1385#  endif
1386
1387template <class _CharT, class _Traits>
1388inline basic_fstream<_CharT, _Traits>::basic_fstream(const string& __s, ios_base::openmode __mode)
1389    : basic_iostream<char_type, traits_type>(&__sb_) {
1390  if (__sb_.open(__s, __mode) == nullptr)
1391    this->setstate(ios_base::failbit);
1392}
1393
1394template <class _CharT, class _Traits>
1395inline basic_fstream<_CharT, _Traits>::basic_fstream(basic_fstream&& __rhs)
1396    : basic_iostream<char_type, traits_type>(std::move(__rhs)), __sb_(std::move(__rhs.__sb_)) {
1397  this->set_rdbuf(&__sb_);
1398}
1399
1400template <class _CharT, class _Traits>
1401inline basic_fstream<_CharT, _Traits>& basic_fstream<_CharT, _Traits>::operator=(basic_fstream&& __rhs) {
1402  basic_iostream<char_type, traits_type>::operator=(std::move(__rhs));
1403  __sb_ = std::move(__rhs.__sb_);
1404  return *this;
1405}
1406
1407template <class _CharT, class _Traits>
1408inline void basic_fstream<_CharT, _Traits>::swap(basic_fstream& __rhs) {
1409  basic_iostream<char_type, traits_type>::swap(__rhs);
1410  __sb_.swap(__rhs.__sb_);
1411}
1412
1413template <class _CharT, class _Traits>
1414inline _LIBCPP_HIDE_FROM_ABI void swap(basic_fstream<_CharT, _Traits>& __x, basic_fstream<_CharT, _Traits>& __y) {
1415  __x.swap(__y);
1416}
1417
1418template <class _CharT, class _Traits>
1419inline basic_filebuf<_CharT, _Traits>* basic_fstream<_CharT, _Traits>::rdbuf() const {
1420  return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1421}
1422
1423template <class _CharT, class _Traits>
1424inline bool basic_fstream<_CharT, _Traits>::is_open() const {
1425  return __sb_.is_open();
1426}
1427
1428template <class _CharT, class _Traits>
1429void basic_fstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
1430  if (__sb_.open(__s, __mode))
1431    this->clear();
1432  else
1433    this->setstate(ios_base::failbit);
1434}
1435
1436#  ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1437template <class _CharT, class _Traits>
1438void basic_fstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode) {
1439  if (__sb_.open(__s, __mode))
1440    this->clear();
1441  else
1442    this->setstate(ios_base::failbit);
1443}
1444#  endif
1445
1446template <class _CharT, class _Traits>
1447void basic_fstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode) {
1448  if (__sb_.open(__s, __mode))
1449    this->clear();
1450  else
1451    this->setstate(ios_base::failbit);
1452}
1453
1454template <class _CharT, class _Traits>
1455inline void basic_fstream<_CharT, _Traits>::close() {
1456  if (__sb_.close() == nullptr)
1457    this->setstate(ios_base::failbit);
1458}
1459
1460#  if _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1
1461extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ifstream<char>;
1462extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ofstream<char>;
1463extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_filebuf<char>;
1464#  endif
1465
1466_LIBCPP_END_NAMESPACE_STD
1467
1468#endif // _LIBCPP_HAS_NO_FILESYSTEM
1469
1470_LIBCPP_POP_MACROS
1471
1472#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1473#  include <atomic>
1474#  include <concepts>
1475#  include <cstdlib>
1476#  include <iosfwd>
1477#  include <limits>
1478#  include <mutex>
1479#  include <new>
1480#  include <stdexcept>
1481#  include <type_traits>
1482#endif
1483
1484#endif // _LIBCPP_FSTREAM
1485