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
215    : public basic_streambuf<_CharT, _Traits>
216{
217public:
218    typedef _CharT                           char_type;
219    typedef _Traits                          traits_type;
220    typedef typename traits_type::int_type   int_type;
221    typedef typename traits_type::pos_type   pos_type;
222    typedef typename traits_type::off_type   off_type;
223    typedef typename traits_type::state_type state_type;
224
225    // 27.9.1.2 Constructors/destructor:
226    basic_filebuf();
227    basic_filebuf(basic_filebuf&& __rhs);
228    ~basic_filebuf() override;
229
230    // 27.9.1.3 Assign/swap:
231    _LIBCPP_HIDE_FROM_ABI
232    basic_filebuf& operator=(basic_filebuf&& __rhs);
233    void swap(basic_filebuf& __rhs);
234
235    // 27.9.1.4 Members:
236    _LIBCPP_HIDE_FROM_ABI
237    bool is_open() const;
238    basic_filebuf* open(const char* __s, ios_base::openmode __mode);
239#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
240    basic_filebuf* open(const wchar_t* __s, ios_base::openmode __mode);
241#endif
242    _LIBCPP_HIDE_FROM_ABI
243    basic_filebuf* open(const string& __s, ios_base::openmode __mode);
244
245#if _LIBCPP_STD_VER >= 17
246    _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI
247    basic_filebuf* open(const filesystem::path& __p, ios_base::openmode __mode) {
248      return open(__p.c_str(), __mode);
249    }
250#endif
251    _LIBCPP_HIDE_FROM_ABI
252    basic_filebuf* __open(int __fd, ios_base::openmode __mode);
253    basic_filebuf* close();
254
255    _LIBCPP_HIDE_FROM_ABI
256    inline static const char*
257    __make_mdstring(ios_base::openmode __mode) _NOEXCEPT;
258
259  protected:
260    // 27.9.1.5 Overridden virtual functions:
261    int_type underflow() override;
262    int_type pbackfail(int_type __c = traits_type::eof()) override;
263    int_type overflow (int_type __c = traits_type::eof()) override;
264    basic_streambuf<char_type, traits_type>* setbuf(char_type* __s, streamsize __n) override;
265    pos_type seekoff(off_type __off, ios_base::seekdir __way,
266                     ios_base::openmode __wch = ios_base::in | ios_base::out) override;
267    pos_type seekpos(pos_type __sp,
268                     ios_base::openmode __wch = ios_base::in | ios_base::out) override;
269    int sync() override;
270    void imbue(const locale& __loc) override;
271
272private:
273  char* __extbuf_;
274  const char* __extbufnext_;
275  const char* __extbufend_;
276  char __extbuf_min_[8];
277  size_t __ebs_;
278  char_type* __intbuf_;
279  size_t __ibs_;
280  FILE* __file_;
281  const codecvt<char_type, char, state_type>* __cv_;
282  state_type __st_;
283  state_type __st_last_;
284  ios_base::openmode __om_;
285  ios_base::openmode __cm_;
286  bool __owns_eb_;
287  bool __owns_ib_;
288  bool __always_noconv_;
289
290  bool __read_mode();
291  void __write_mode();
292};
293
294template <class _CharT, class _Traits>
295basic_filebuf<_CharT, _Traits>::basic_filebuf()
296    : __extbuf_(nullptr),
297      __extbufnext_(nullptr),
298      __extbufend_(nullptr),
299      __ebs_(0),
300      __intbuf_(nullptr),
301      __ibs_(0),
302      __file_(nullptr),
303      __cv_(nullptr),
304      __st_(),
305      __st_last_(),
306      __om_(0),
307      __cm_(0),
308      __owns_eb_(false),
309      __owns_ib_(false),
310      __always_noconv_(false)
311{
312    if (std::has_facet<codecvt<char_type, char, state_type> >(this->getloc()))
313    {
314        __cv_ = &std::use_facet<codecvt<char_type, char, state_type> >(this->getloc());
315        __always_noconv_ = __cv_->always_noconv();
316    }
317    setbuf(nullptr, 4096);
318}
319
320template <class _CharT, class _Traits>
321basic_filebuf<_CharT, _Traits>::basic_filebuf(basic_filebuf&& __rhs)
322    : basic_streambuf<_CharT, _Traits>(__rhs)
323{
324    if (__rhs.__extbuf_ == __rhs.__extbuf_min_)
325    {
326        __extbuf_ = __extbuf_min_;
327        __extbufnext_ = __extbuf_ + (__rhs.__extbufnext_ - __rhs.__extbuf_);
328        __extbufend_ = __extbuf_ + (__rhs.__extbufend_ - __rhs.__extbuf_);
329    }
330    else
331    {
332        __extbuf_ = __rhs.__extbuf_;
333        __extbufnext_ = __rhs.__extbufnext_;
334        __extbufend_ = __rhs.__extbufend_;
335    }
336    __ebs_ = __rhs.__ebs_;
337    __intbuf_ = __rhs.__intbuf_;
338    __ibs_ = __rhs.__ibs_;
339    __file_ = __rhs.__file_;
340    __cv_ = __rhs.__cv_;
341    __st_ = __rhs.__st_;
342    __st_last_ = __rhs.__st_last_;
343    __om_ = __rhs.__om_;
344    __cm_ = __rhs.__cm_;
345    __owns_eb_ = __rhs.__owns_eb_;
346    __owns_ib_ = __rhs.__owns_ib_;
347    __always_noconv_ = __rhs.__always_noconv_;
348    if (__rhs.pbase())
349    {
350        if (__rhs.pbase() == __rhs.__intbuf_)
351            this->setp(__intbuf_, __intbuf_ + (__rhs. epptr() - __rhs.pbase()));
352        else
353            this->setp((char_type*)__extbuf_,
354                       (char_type*)__extbuf_ + (__rhs. epptr() - __rhs.pbase()));
355        this->__pbump(__rhs. pptr() - __rhs.pbase());
356    }
357    else if (__rhs.eback())
358    {
359        if (__rhs.eback() == __rhs.__intbuf_)
360            this->setg(__intbuf_, __intbuf_ + (__rhs.gptr() - __rhs.eback()),
361                                  __intbuf_ + (__rhs.egptr() - __rhs.eback()));
362        else
363            this->setg((char_type*)__extbuf_,
364                       (char_type*)__extbuf_ + (__rhs.gptr() - __rhs.eback()),
365                       (char_type*)__extbuf_ + (__rhs.egptr() - __rhs.eback()));
366    }
367    __rhs.__extbuf_ = nullptr;
368    __rhs.__extbufnext_ = nullptr;
369    __rhs.__extbufend_ = nullptr;
370    __rhs.__ebs_ = 0;
371    __rhs.__intbuf_ = 0;
372    __rhs.__ibs_ = 0;
373    __rhs.__file_ = nullptr;
374    __rhs.__st_ = state_type();
375    __rhs.__st_last_ = state_type();
376    __rhs.__om_ = 0;
377    __rhs.__cm_ = 0;
378    __rhs.__owns_eb_ = false;
379    __rhs.__owns_ib_ = false;
380    __rhs.setg(0, 0, 0);
381    __rhs.setp(0, 0);
382}
383
384template <class _CharT, class _Traits>
385inline
386basic_filebuf<_CharT, _Traits>&
387basic_filebuf<_CharT, _Traits>::operator=(basic_filebuf&& __rhs)
388{
389    close();
390    swap(__rhs);
391    return *this;
392}
393
394template <class _CharT, class _Traits>
395basic_filebuf<_CharT, _Traits>::~basic_filebuf()
396{
397#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
398    try
399    {
400#endif // _LIBCPP_HAS_NO_EXCEPTIONS
401        close();
402#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
403    }
404    catch (...)
405    {
406    }
407#endif // _LIBCPP_HAS_NO_EXCEPTIONS
408    if (__owns_eb_)
409        delete [] __extbuf_;
410    if (__owns_ib_)
411        delete [] __intbuf_;
412}
413
414template <class _CharT, class _Traits>
415void
416basic_filebuf<_CharT, _Traits>::swap(basic_filebuf& __rhs)
417{
418    basic_streambuf<char_type, traits_type>::swap(__rhs);
419    if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_)
420    {
421        // Neither *this nor __rhs uses the small buffer, so we can simply swap the pointers.
422        std::swap(__extbuf_, __rhs.__extbuf_);
423        std::swap(__extbufnext_, __rhs.__extbufnext_);
424        std::swap(__extbufend_, __rhs.__extbufend_);
425    }
426    else
427    {
428        ptrdiff_t __ln = __extbufnext_       ? __extbufnext_ - __extbuf_             : 0;
429        ptrdiff_t __le = __extbufend_        ? __extbufend_ - __extbuf_              : 0;
430        ptrdiff_t __rn = __rhs.__extbufnext_ ? __rhs.__extbufnext_ - __rhs.__extbuf_ : 0;
431        ptrdiff_t __re = __rhs.__extbufend_  ? __rhs.__extbufend_ - __rhs.__extbuf_  : 0;
432        if (__extbuf_ == __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_)
433        {
434            // *this uses the small buffer, but __rhs doesn't.
435            __extbuf_ = __rhs.__extbuf_;
436            __rhs.__extbuf_ = __rhs.__extbuf_min_;
437            std::memmove(__rhs.__extbuf_min_, __extbuf_min_, sizeof(__extbuf_min_));
438        }
439        else if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ == __rhs.__extbuf_min_)
440        {
441            // *this doesn't use the small buffer, but __rhs does.
442            __rhs.__extbuf_ = __extbuf_;
443            __extbuf_ = __extbuf_min_;
444            std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));
445        }
446        else
447        {
448            // Both *this and __rhs use the small buffer.
449            char __tmp[sizeof(__extbuf_min_)];
450            std::memmove(__tmp, __extbuf_min_, sizeof(__extbuf_min_));
451            std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));
452            std::memmove(__rhs.__extbuf_min_, __tmp, sizeof(__extbuf_min_));
453        }
454        __extbufnext_ = __extbuf_ + __rn;
455        __extbufend_ = __extbuf_ + __re;
456        __rhs.__extbufnext_ = __rhs.__extbuf_ + __ln;
457        __rhs.__extbufend_ = __rhs.__extbuf_ + __le;
458    }
459    std::swap(__ebs_, __rhs.__ebs_);
460    std::swap(__intbuf_, __rhs.__intbuf_);
461    std::swap(__ibs_, __rhs.__ibs_);
462    std::swap(__file_, __rhs.__file_);
463    std::swap(__cv_, __rhs.__cv_);
464    std::swap(__st_, __rhs.__st_);
465    std::swap(__st_last_, __rhs.__st_last_);
466    std::swap(__om_, __rhs.__om_);
467    std::swap(__cm_, __rhs.__cm_);
468    std::swap(__owns_eb_, __rhs.__owns_eb_);
469    std::swap(__owns_ib_, __rhs.__owns_ib_);
470    std::swap(__always_noconv_, __rhs.__always_noconv_);
471    if (this->eback() == (char_type*)__rhs.__extbuf_min_)
472    {
473        ptrdiff_t __n = this->gptr() - this->eback();
474        ptrdiff_t __e = this->egptr() - this->eback();
475        this->setg((char_type*)__extbuf_min_,
476                   (char_type*)__extbuf_min_ + __n,
477                   (char_type*)__extbuf_min_ + __e);
478    }
479    else if (this->pbase() == (char_type*)__rhs.__extbuf_min_)
480    {
481        ptrdiff_t __n = this->pptr() - this->pbase();
482        ptrdiff_t __e = this->epptr() - this->pbase();
483        this->setp((char_type*)__extbuf_min_,
484                   (char_type*)__extbuf_min_ + __e);
485        this->__pbump(__n);
486    }
487    if (__rhs.eback() == (char_type*)__extbuf_min_)
488    {
489        ptrdiff_t __n = __rhs.gptr() - __rhs.eback();
490        ptrdiff_t __e = __rhs.egptr() - __rhs.eback();
491        __rhs.setg((char_type*)__rhs.__extbuf_min_,
492                   (char_type*)__rhs.__extbuf_min_ + __n,
493                   (char_type*)__rhs.__extbuf_min_ + __e);
494    }
495    else if (__rhs.pbase() == (char_type*)__extbuf_min_)
496    {
497        ptrdiff_t __n = __rhs.pptr() - __rhs.pbase();
498        ptrdiff_t __e = __rhs.epptr() - __rhs.pbase();
499        __rhs.setp((char_type*)__rhs.__extbuf_min_,
500                   (char_type*)__rhs.__extbuf_min_ + __e);
501        __rhs.__pbump(__n);
502    }
503}
504
505template <class _CharT, class _Traits>
506inline _LIBCPP_HIDE_FROM_ABI
507void
508swap(basic_filebuf<_CharT, _Traits>& __x, basic_filebuf<_CharT, _Traits>& __y)
509{
510    __x.swap(__y);
511}
512
513template <class _CharT, class _Traits>
514inline
515bool
516basic_filebuf<_CharT, _Traits>::is_open() const
517{
518    return __file_ != nullptr;
519}
520
521template <class _CharT, class _Traits>
522const char* basic_filebuf<_CharT, _Traits>::__make_mdstring(
523    ios_base::openmode __mode) _NOEXCEPT {
524  switch (__mode & ~ios_base::ate) {
525  case ios_base::out:
526  case ios_base::out | ios_base::trunc:
527    return "w" _LIBCPP_FOPEN_CLOEXEC_MODE;
528  case ios_base::out | ios_base::app:
529  case ios_base::app:
530    return "a" _LIBCPP_FOPEN_CLOEXEC_MODE;
531  case ios_base::in:
532    return "r" _LIBCPP_FOPEN_CLOEXEC_MODE;
533  case ios_base::in | ios_base::out:
534    return "r+" _LIBCPP_FOPEN_CLOEXEC_MODE;
535  case ios_base::in | ios_base::out | ios_base::trunc:
536    return "w+" _LIBCPP_FOPEN_CLOEXEC_MODE;
537  case ios_base::in | ios_base::out | ios_base::app:
538  case ios_base::in | ios_base::app:
539    return "a+" _LIBCPP_FOPEN_CLOEXEC_MODE;
540  case ios_base::out | ios_base::binary:
541  case ios_base::out | ios_base::trunc | ios_base::binary:
542    return "wb" _LIBCPP_FOPEN_CLOEXEC_MODE;
543  case ios_base::out | ios_base::app | ios_base::binary:
544  case ios_base::app | ios_base::binary:
545    return "ab" _LIBCPP_FOPEN_CLOEXEC_MODE;
546  case ios_base::in | ios_base::binary:
547    return "rb" _LIBCPP_FOPEN_CLOEXEC_MODE;
548  case ios_base::in | ios_base::out | ios_base::binary:
549    return "r+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
550  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
551    return "w+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
552  case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
553  case ios_base::in | ios_base::app | ios_base::binary:
554    return "a+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
555#if _LIBCPP_STD_VER >= 23
556  case ios_base::out | ios_base::noreplace:
557  case ios_base::out | ios_base::trunc | ios_base::noreplace:
558    return "wx" _LIBCPP_FOPEN_CLOEXEC_MODE;
559  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:
560    return "w+x" _LIBCPP_FOPEN_CLOEXEC_MODE;
561  case ios_base::out | ios_base::binary | ios_base::noreplace:
562  case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
563    return "wbx" _LIBCPP_FOPEN_CLOEXEC_MODE;
564  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
565    return "w+bx" _LIBCPP_FOPEN_CLOEXEC_MODE;
566#endif // _LIBCPP_STD_VER >= 23
567  default:
568    return nullptr;
569  }
570  __libcpp_unreachable();
571}
572
573template <class _CharT, class _Traits>
574basic_filebuf<_CharT, _Traits>*
575basic_filebuf<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
576{
577    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
578    if (__file_ == nullptr)
579    {
580      if (const char* __mdstr = __make_mdstring(__mode)) {
581        __rt = this;
582        __file_ = fopen(__s, __mdstr);
583        if (__file_) {
584          __om_ = __mode;
585          if (__mode & ios_base::ate) {
586            if (fseek(__file_, 0, SEEK_END)) {
587              fclose(__file_);
588              __file_ = nullptr;
589              __rt = nullptr;
590            }
591          }
592        } else
593          __rt = nullptr;
594      }
595    }
596    return __rt;
597}
598
599template <class _CharT, class _Traits>
600inline
601basic_filebuf<_CharT, _Traits>*
602basic_filebuf<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
603  basic_filebuf<_CharT, _Traits>* __rt = nullptr;
604  if (__file_ == nullptr) {
605    if (const char* __mdstr = __make_mdstring(__mode)) {
606      __rt = this;
607      __file_ = fdopen(__fd, __mdstr);
608      if (__file_) {
609        __om_ = __mode;
610        if (__mode & ios_base::ate) {
611          if (fseek(__file_, 0, SEEK_END)) {
612            fclose(__file_);
613            __file_ = nullptr;
614            __rt = nullptr;
615          }
616        }
617      } else
618        __rt = nullptr;
619    }
620  }
621  return __rt;
622}
623
624#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
625// This is basically the same as the char* overload except that it uses _wfopen
626// and long mode strings.
627template <class _CharT, class _Traits>
628basic_filebuf<_CharT, _Traits>*
629basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
630{
631    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
632    if (__file_ == nullptr)
633    {
634        __rt = this;
635        const wchar_t* __mdstr;
636        switch (__mode & ~ios_base::ate)
637        {
638        case ios_base::out:
639        case ios_base::out | ios_base::trunc:
640            __mdstr = L"w";
641            break;
642        case ios_base::out | ios_base::app:
643        case ios_base::app:
644            __mdstr = L"a";
645            break;
646        case ios_base::in:
647            __mdstr = L"r";
648            break;
649        case ios_base::in | ios_base::out:
650            __mdstr = L"r+";
651            break;
652        case ios_base::in | ios_base::out | ios_base::trunc:
653            __mdstr = L"w+";
654            break;
655        case ios_base::in | ios_base::out | ios_base::app:
656        case ios_base::in | ios_base::app:
657            __mdstr = L"a+";
658            break;
659        case ios_base::out | ios_base::binary:
660        case ios_base::out | ios_base::trunc | ios_base::binary:
661            __mdstr = L"wb";
662            break;
663        case ios_base::out | ios_base::app | ios_base::binary:
664        case ios_base::app | ios_base::binary:
665            __mdstr = L"ab";
666            break;
667        case ios_base::in | ios_base::binary:
668            __mdstr = L"rb";
669            break;
670        case ios_base::in | ios_base::out | ios_base::binary:
671            __mdstr = L"r+b";
672            break;
673        case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
674            __mdstr = L"w+b";
675            break;
676        case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
677        case ios_base::in | ios_base::app | ios_base::binary:
678            __mdstr = L"a+b";
679            break;
680#  if _LIBCPP_STD_VER >= 23
681        case ios_base::out | ios_base::noreplace:
682        case ios_base::out | ios_base::trunc | ios_base::noreplace:
683          __mdstr = L"wx";
684          break;
685        case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:
686          __mdstr = L"w+x";
687          break;
688        case ios_base::out | ios_base::binary | ios_base::noreplace:
689        case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
690          __mdstr = L"wbx";
691          break;
692        case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
693          __mdstr = L"w+bx";
694          break;
695#  endif // _LIBCPP_STD_VER >= 23
696        default:
697            __rt = nullptr;
698            break;
699        }
700        if (__rt)
701        {
702            __file_ = _wfopen(__s, __mdstr);
703            if (__file_)
704            {
705                __om_ = __mode;
706                if (__mode & ios_base::ate)
707                {
708                    if (fseek(__file_, 0, SEEK_END))
709                    {
710                        fclose(__file_);
711                        __file_ = nullptr;
712                        __rt = nullptr;
713                    }
714                }
715            }
716            else
717                __rt = nullptr;
718        }
719    }
720    return __rt;
721}
722#endif
723
724template <class _CharT, class _Traits>
725inline
726basic_filebuf<_CharT, _Traits>*
727basic_filebuf<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
728{
729    return open(__s.c_str(), __mode);
730}
731
732template <class _CharT, class _Traits>
733basic_filebuf<_CharT, _Traits>*
734basic_filebuf<_CharT, _Traits>::close()
735{
736    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
737    if (__file_)
738    {
739        __rt = this;
740        unique_ptr<FILE, int(*)(FILE*)> __h(__file_, fclose);
741        if (sync())
742            __rt = nullptr;
743        if (fclose(__h.release()))
744            __rt = nullptr;
745        __file_ = nullptr;
746        setbuf(0, 0);
747    }
748    return __rt;
749}
750
751template <class _CharT, class _Traits>
752typename basic_filebuf<_CharT, _Traits>::int_type
753basic_filebuf<_CharT, _Traits>::underflow()
754{
755    if (__file_ == nullptr)
756        return traits_type::eof();
757    bool __initial = __read_mode();
758    char_type __1buf;
759    if (this->gptr() == nullptr)
760        this->setg(&__1buf, &__1buf+1, &__1buf+1);
761    const size_t __unget_sz = __initial ? 0 : std::min<size_t>((this->egptr() - this->eback()) / 2, 4);
762    int_type __c = traits_type::eof();
763    if (this->gptr() == this->egptr())
764    {
765        std::memmove(this->eback(), this->egptr() - __unget_sz, __unget_sz * sizeof(char_type));
766        if (__always_noconv_)
767        {
768            size_t __nmemb = static_cast<size_t>(this->egptr() - this->eback() - __unget_sz);
769            __nmemb = ::fread(this->eback() + __unget_sz, 1, __nmemb, __file_);
770            if (__nmemb != 0)
771            {
772                this->setg(this->eback(),
773                           this->eback() + __unget_sz,
774                           this->eback() + __unget_sz + __nmemb);
775                __c = traits_type::to_int_type(*this->gptr());
776            }
777        }
778        else
779        {
780            if (__extbufend_ != __extbufnext_) {
781                _LIBCPP_ASSERT_NON_NULL(__extbufnext_ != nullptr, "underflow moving from nullptr");
782                _LIBCPP_ASSERT_NON_NULL(__extbuf_ != nullptr, "underflow moving into nullptr");
783                std::memmove(__extbuf_, __extbufnext_, __extbufend_ - __extbufnext_);
784            }
785            __extbufnext_ = __extbuf_ + (__extbufend_ - __extbufnext_);
786            __extbufend_ = __extbuf_ + (__extbuf_ == __extbuf_min_ ? sizeof(__extbuf_min_) : __ebs_);
787            size_t __nmemb = std::min(static_cast<size_t>(__ibs_ - __unget_sz),
788                                 static_cast<size_t>(__extbufend_ - __extbufnext_));
789            codecvt_base::result __r;
790            __st_last_ = __st_;
791            size_t __nr = fread((void*) const_cast<char *>(__extbufnext_), 1, __nmemb, __file_);
792            if (__nr != 0)
793            {
794                if (!__cv_)
795                    __throw_bad_cast();
796
797                __extbufend_ = __extbufnext_ + __nr;
798                char_type*  __inext;
799                __r = __cv_->in(__st_, __extbuf_, __extbufend_, __extbufnext_,
800                                       this->eback() + __unget_sz,
801                                       this->eback() + __ibs_, __inext);
802                if (__r == codecvt_base::noconv)
803                {
804                    this->setg((char_type*)__extbuf_, (char_type*)__extbuf_,
805                                          (char_type*)const_cast<char *>(__extbufend_));
806                    __c = traits_type::to_int_type(*this->gptr());
807                }
808                else if (__inext != this->eback() + __unget_sz)
809                {
810                    this->setg(this->eback(), this->eback() + __unget_sz, __inext);
811                    __c = traits_type::to_int_type(*this->gptr());
812                }
813            }
814        }
815    }
816    else
817        __c = traits_type::to_int_type(*this->gptr());
818    if (this->eback() == &__1buf)
819        this->setg(nullptr, nullptr, nullptr);
820    return __c;
821}
822
823template <class _CharT, class _Traits>
824typename basic_filebuf<_CharT, _Traits>::int_type
825basic_filebuf<_CharT, _Traits>::pbackfail(int_type __c)
826{
827    if (__file_ && this->eback() < this->gptr())
828    {
829        if (traits_type::eq_int_type(__c, traits_type::eof()))
830        {
831            this->gbump(-1);
832            return traits_type::not_eof(__c);
833        }
834        if ((__om_ & ios_base::out) ||
835            traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1]))
836        {
837            this->gbump(-1);
838            *this->gptr() = traits_type::to_char_type(__c);
839            return __c;
840        }
841    }
842    return traits_type::eof();
843}
844
845template <class _CharT, class _Traits>
846typename basic_filebuf<_CharT, _Traits>::int_type
847basic_filebuf<_CharT, _Traits>::overflow(int_type __c)
848{
849    if (__file_ == nullptr)
850        return traits_type::eof();
851    __write_mode();
852    char_type __1buf;
853    char_type* __pb_save = this->pbase();
854    char_type* __epb_save = this->epptr();
855    if (!traits_type::eq_int_type(__c, traits_type::eof()))
856    {
857        if (this->pptr() == nullptr)
858            this->setp(&__1buf, &__1buf+1);
859        *this->pptr() = traits_type::to_char_type(__c);
860        this->pbump(1);
861    }
862    if (this->pptr() != this->pbase())
863    {
864        if (__always_noconv_)
865        {
866            size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
867            if (std::fwrite(this->pbase(), sizeof(char_type), __nmemb, __file_) != __nmemb)
868                return traits_type::eof();
869        }
870        else
871        {
872            char* __extbe = __extbuf_;
873            codecvt_base::result __r;
874            do
875            {
876                if (!__cv_)
877                    __throw_bad_cast();
878
879                const char_type* __e;
880                __r = __cv_->out(__st_, this->pbase(), this->pptr(), __e,
881                                        __extbuf_, __extbuf_ + __ebs_, __extbe);
882                if (__e == this->pbase())
883                    return traits_type::eof();
884                if (__r == codecvt_base::noconv)
885                {
886                    size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
887                    if (std::fwrite(this->pbase(), 1, __nmemb, __file_) != __nmemb)
888                        return traits_type::eof();
889                }
890                else if (__r == codecvt_base::ok || __r == codecvt_base::partial)
891                {
892                    size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
893                    if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
894                        return traits_type::eof();
895                    if (__r == codecvt_base::partial)
896                    {
897                        this->setp(const_cast<char_type*>(__e), this->pptr());
898                        this->__pbump(this->epptr() - this->pbase());
899                    }
900                }
901                else
902                    return traits_type::eof();
903            } while (__r == codecvt_base::partial);
904        }
905        this->setp(__pb_save, __epb_save);
906    }
907    return traits_type::not_eof(__c);
908}
909
910template <class _CharT, class _Traits>
911basic_streambuf<_CharT, _Traits>*
912basic_filebuf<_CharT, _Traits>::setbuf(char_type* __s, streamsize __n)
913{
914    this->setg(nullptr, nullptr, nullptr);
915    this->setp(nullptr, nullptr);
916    if (__owns_eb_)
917        delete [] __extbuf_;
918    if (__owns_ib_)
919        delete [] __intbuf_;
920    __ebs_ = __n;
921    if (__ebs_ > sizeof(__extbuf_min_))
922    {
923        if (__always_noconv_ && __s)
924        {
925            __extbuf_ = (char*)__s;
926            __owns_eb_ = false;
927        }
928        else
929        {
930            __extbuf_ = new char[__ebs_];
931            __owns_eb_ = true;
932        }
933    }
934    else
935    {
936        __extbuf_ = __extbuf_min_;
937        __ebs_ = sizeof(__extbuf_min_);
938        __owns_eb_ = false;
939    }
940    if (!__always_noconv_)
941    {
942        __ibs_ = max<streamsize>(__n, sizeof(__extbuf_min_));
943        if (__s && __ibs_ > sizeof(__extbuf_min_))
944        {
945            __intbuf_ = __s;
946            __owns_ib_ = false;
947        }
948        else
949        {
950            __intbuf_ = new char_type[__ibs_];
951            __owns_ib_ = true;
952        }
953    }
954    else
955    {
956        __ibs_ = 0;
957        __intbuf_ = nullptr;
958        __owns_ib_ = false;
959    }
960    return this;
961}
962
963template <class _CharT, class _Traits>
964typename basic_filebuf<_CharT, _Traits>::pos_type
965basic_filebuf<_CharT, _Traits>::seekoff(off_type __off, ios_base::seekdir __way,
966                                        ios_base::openmode)
967{
968    if (!__cv_)
969        __throw_bad_cast();
970
971    int __width = __cv_->encoding();
972    if (__file_ == nullptr || (__width <= 0 && __off != 0) || sync())
973        return pos_type(off_type(-1));
974    // __width > 0 || __off == 0
975    int __whence;
976    switch (__way)
977    {
978    case ios_base::beg:
979        __whence = SEEK_SET;
980        break;
981    case ios_base::cur:
982        __whence = SEEK_CUR;
983        break;
984    case ios_base::end:
985        __whence = SEEK_END;
986        break;
987    default:
988        return pos_type(off_type(-1));
989    }
990#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
991    if (fseek(__file_, __width > 0 ? __width * __off : 0, __whence))
992        return pos_type(off_type(-1));
993    pos_type __r = ftell(__file_);
994#else
995    if (::fseeko(__file_, __width > 0 ? __width * __off : 0, __whence))
996        return pos_type(off_type(-1));
997    pos_type __r = ftello(__file_);
998#endif
999    __r.state(__st_);
1000    return __r;
1001}
1002
1003template <class _CharT, class _Traits>
1004typename basic_filebuf<_CharT, _Traits>::pos_type
1005basic_filebuf<_CharT, _Traits>::seekpos(pos_type __sp, ios_base::openmode)
1006{
1007    if (__file_ == nullptr || sync())
1008        return pos_type(off_type(-1));
1009#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
1010    if (fseek(__file_, __sp, SEEK_SET))
1011        return pos_type(off_type(-1));
1012#else
1013    if (::fseeko(__file_, __sp, SEEK_SET))
1014        return pos_type(off_type(-1));
1015#endif
1016    __st_ = __sp.state();
1017    return __sp;
1018}
1019
1020template <class _CharT, class _Traits>
1021int
1022basic_filebuf<_CharT, _Traits>::sync()
1023{
1024    if (__file_ == nullptr)
1025        return 0;
1026    if (!__cv_)
1027        __throw_bad_cast();
1028
1029    if (__cm_ & ios_base::out)
1030    {
1031        if (this->pptr() != this->pbase())
1032            if (overflow() == traits_type::eof())
1033                return -1;
1034        codecvt_base::result __r;
1035        do
1036        {
1037            char* __extbe;
1038            __r = __cv_->unshift(__st_, __extbuf_, __extbuf_ + __ebs_, __extbe);
1039            size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
1040            if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
1041                return -1;
1042        } while (__r == codecvt_base::partial);
1043        if (__r == codecvt_base::error)
1044            return -1;
1045        if (fflush(__file_))
1046            return -1;
1047    }
1048    else if (__cm_ & ios_base::in)
1049    {
1050        off_type __c;
1051        state_type __state = __st_last_;
1052        bool __update_st = false;
1053        if (__always_noconv_)
1054            __c = this->egptr() - this->gptr();
1055        else
1056        {
1057            int __width = __cv_->encoding();
1058            __c = __extbufend_ - __extbufnext_;
1059            if (__width > 0)
1060                __c += __width * (this->egptr() - this->gptr());
1061            else
1062            {
1063                if (this->gptr() != this->egptr())
1064                {
1065                    const int __off =  __cv_->length(__state, __extbuf_,
1066                                                     __extbufnext_,
1067                                                     this->gptr() - this->eback());
1068                    __c += __extbufnext_ - __extbuf_ - __off;
1069                    __update_st = true;
1070                }
1071            }
1072        }
1073#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
1074        if (fseek(__file_, -__c, SEEK_CUR))
1075            return -1;
1076#else
1077        if (::fseeko(__file_, -__c, SEEK_CUR))
1078            return -1;
1079#endif
1080        if (__update_st)
1081            __st_ = __state;
1082        __extbufnext_ = __extbufend_ = __extbuf_;
1083        this->setg(nullptr, nullptr, nullptr);
1084        __cm_ = 0;
1085    }
1086    return 0;
1087}
1088
1089template <class _CharT, class _Traits>
1090void
1091basic_filebuf<_CharT, _Traits>::imbue(const locale& __loc)
1092{
1093    sync();
1094    __cv_ = &std::use_facet<codecvt<char_type, char, state_type> >(__loc);
1095    bool __old_anc = __always_noconv_;
1096    __always_noconv_ = __cv_->always_noconv();
1097    if (__old_anc != __always_noconv_)
1098    {
1099        this->setg(nullptr, nullptr, nullptr);
1100        this->setp(nullptr, nullptr);
1101        // invariant, char_type is char, else we couldn't get here
1102        if (__always_noconv_)  // need to dump __intbuf_
1103        {
1104            if (__owns_eb_)
1105                delete [] __extbuf_;
1106            __owns_eb_ = __owns_ib_;
1107            __ebs_ = __ibs_;
1108            __extbuf_ = (char*)__intbuf_;
1109            __ibs_ = 0;
1110            __intbuf_ = nullptr;
1111            __owns_ib_ = false;
1112        }
1113        else  // need to obtain an __intbuf_.
1114        {     // If __extbuf_ is user-supplied, use it, else new __intbuf_
1115            if (!__owns_eb_ && __extbuf_ != __extbuf_min_)
1116            {
1117                __ibs_ = __ebs_;
1118                __intbuf_ = (char_type*)__extbuf_;
1119                __owns_ib_ = false;
1120                __extbuf_ = new char[__ebs_];
1121                __owns_eb_ = true;
1122            }
1123            else
1124            {
1125                __ibs_ = __ebs_;
1126                __intbuf_ = new char_type[__ibs_];
1127                __owns_ib_ = true;
1128            }
1129        }
1130    }
1131}
1132
1133template <class _CharT, class _Traits>
1134bool
1135basic_filebuf<_CharT, _Traits>::__read_mode()
1136{
1137    if (!(__cm_ & ios_base::in))
1138    {
1139        this->setp(nullptr, nullptr);
1140        if (__always_noconv_)
1141            this->setg((char_type*)__extbuf_,
1142                       (char_type*)__extbuf_ + __ebs_,
1143                       (char_type*)__extbuf_ + __ebs_);
1144        else
1145            this->setg(__intbuf_, __intbuf_ + __ibs_, __intbuf_ + __ibs_);
1146        __cm_ = ios_base::in;
1147        return true;
1148    }
1149    return false;
1150}
1151
1152template <class _CharT, class _Traits>
1153void
1154basic_filebuf<_CharT, _Traits>::__write_mode()
1155{
1156    if (!(__cm_ & ios_base::out))
1157    {
1158        this->setg(nullptr, nullptr, nullptr);
1159        if (__ebs_ > sizeof(__extbuf_min_))
1160        {
1161            if (__always_noconv_)
1162                this->setp((char_type*)__extbuf_,
1163                           (char_type*)__extbuf_ + (__ebs_ - 1));
1164            else
1165                this->setp(__intbuf_, __intbuf_ + (__ibs_ - 1));
1166        }
1167        else
1168            this->setp(nullptr, nullptr);
1169        __cm_ = ios_base::out;
1170    }
1171}
1172
1173// basic_ifstream
1174
1175template <class _CharT, class _Traits>
1176class _LIBCPP_TEMPLATE_VIS basic_ifstream
1177    : public basic_istream<_CharT, _Traits>
1178{
1179public:
1180    typedef _CharT                         char_type;
1181    typedef _Traits                        traits_type;
1182    typedef typename traits_type::int_type int_type;
1183    typedef typename traits_type::pos_type pos_type;
1184    typedef typename traits_type::off_type off_type;
1185
1186    _LIBCPP_HIDE_FROM_ABI
1187    basic_ifstream();
1188    _LIBCPP_HIDE_FROM_ABI
1189    explicit basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in);
1190#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1191    _LIBCPP_HIDE_FROM_ABI
1192    explicit basic_ifstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
1193#endif
1194    _LIBCPP_HIDE_FROM_ABI
1195    explicit basic_ifstream(const string& __s, ios_base::openmode __mode = ios_base::in);
1196#if _LIBCPP_STD_VER >= 17
1197    _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI
1198    explicit basic_ifstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in)
1199      : basic_ifstream(__p.c_str(), __mode) {}
1200#endif // _LIBCPP_STD_VER >= 17
1201    _LIBCPP_HIDE_FROM_ABI
1202    basic_ifstream(basic_ifstream&& __rhs);
1203    _LIBCPP_HIDE_FROM_ABI
1204    basic_ifstream& operator=(basic_ifstream&& __rhs);
1205    _LIBCPP_HIDE_FROM_ABI
1206    void swap(basic_ifstream& __rhs);
1207
1208    _LIBCPP_HIDE_FROM_ABI
1209    basic_filebuf<char_type, traits_type>* rdbuf() const;
1210    _LIBCPP_HIDE_FROM_ABI
1211    bool is_open() const;
1212    void open(const char* __s, ios_base::openmode __mode = ios_base::in);
1213#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1214    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
1215#endif
1216    void open(const string& __s, ios_base::openmode __mode = ios_base::in);
1217#if _LIBCPP_STD_VER >= 17
1218    _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI
1219    void open(const filesystem::path& __p,
1220              ios_base::openmode __mode = ios_base::in) {
1221      return open(__p.c_str(), __mode);
1222    }
1223#endif // _LIBCPP_STD_VER >= 17
1224
1225    _LIBCPP_HIDE_FROM_ABI
1226    void __open(int __fd, ios_base::openmode __mode);
1227    _LIBCPP_HIDE_FROM_ABI
1228    void close();
1229
1230private:
1231    basic_filebuf<char_type, traits_type> __sb_;
1232};
1233
1234template <class _CharT, class _Traits>
1235inline
1236basic_ifstream<_CharT, _Traits>::basic_ifstream()
1237    : basic_istream<char_type, traits_type>(&__sb_)
1238{
1239}
1240
1241template <class _CharT, class _Traits>
1242inline
1243basic_ifstream<_CharT, _Traits>::basic_ifstream(const char* __s, ios_base::openmode __mode)
1244    : basic_istream<char_type, traits_type>(&__sb_)
1245{
1246    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1247        this->setstate(ios_base::failbit);
1248}
1249
1250#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1251template <class _CharT, class _Traits>
1252inline
1253basic_ifstream<_CharT, _Traits>::basic_ifstream(const wchar_t* __s, ios_base::openmode __mode)
1254    : basic_istream<char_type, traits_type>(&__sb_)
1255{
1256    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1257        this->setstate(ios_base::failbit);
1258}
1259#endif
1260
1261template <class _CharT, class _Traits>
1262inline
1263basic_ifstream<_CharT, _Traits>::basic_ifstream(const string& __s, ios_base::openmode __mode)
1264    : basic_istream<char_type, traits_type>(&__sb_)
1265{
1266    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1267        this->setstate(ios_base::failbit);
1268}
1269
1270template <class _CharT, class _Traits>
1271inline
1272basic_ifstream<_CharT, _Traits>::basic_ifstream(basic_ifstream&& __rhs)
1273    : basic_istream<char_type, traits_type>(std::move(__rhs)),
1274      __sb_(std::move(__rhs.__sb_))
1275{
1276    this->set_rdbuf(&__sb_);
1277}
1278
1279template <class _CharT, class _Traits>
1280inline
1281basic_ifstream<_CharT, _Traits>&
1282basic_ifstream<_CharT, _Traits>::operator=(basic_ifstream&& __rhs)
1283{
1284    basic_istream<char_type, traits_type>::operator=(std::move(__rhs));
1285    __sb_ = std::move(__rhs.__sb_);
1286    return *this;
1287}
1288
1289template <class _CharT, class _Traits>
1290inline
1291void
1292basic_ifstream<_CharT, _Traits>::swap(basic_ifstream& __rhs)
1293{
1294    basic_istream<char_type, traits_type>::swap(__rhs);
1295    __sb_.swap(__rhs.__sb_);
1296}
1297
1298template <class _CharT, class _Traits>
1299inline _LIBCPP_HIDE_FROM_ABI
1300void
1301swap(basic_ifstream<_CharT, _Traits>& __x, basic_ifstream<_CharT, _Traits>& __y)
1302{
1303    __x.swap(__y);
1304}
1305
1306template <class _CharT, class _Traits>
1307inline
1308basic_filebuf<_CharT, _Traits>*
1309basic_ifstream<_CharT, _Traits>::rdbuf() const
1310{
1311    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1312}
1313
1314template <class _CharT, class _Traits>
1315inline
1316bool
1317basic_ifstream<_CharT, _Traits>::is_open() const
1318{
1319    return __sb_.is_open();
1320}
1321
1322template <class _CharT, class _Traits>
1323void
1324basic_ifstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
1325{
1326    if (__sb_.open(__s, __mode | ios_base::in))
1327        this->clear();
1328    else
1329        this->setstate(ios_base::failbit);
1330}
1331
1332#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1333template <class _CharT, class _Traits>
1334void
1335basic_ifstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
1336{
1337    if (__sb_.open(__s, __mode | ios_base::in))
1338        this->clear();
1339    else
1340        this->setstate(ios_base::failbit);
1341}
1342#endif
1343
1344template <class _CharT, class _Traits>
1345void
1346basic_ifstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
1347{
1348    if (__sb_.open(__s, __mode | ios_base::in))
1349        this->clear();
1350    else
1351        this->setstate(ios_base::failbit);
1352}
1353
1354template <class _CharT, class _Traits>
1355inline
1356void basic_ifstream<_CharT, _Traits>::__open(int __fd,
1357                                             ios_base::openmode __mode) {
1358  if (__sb_.__open(__fd, __mode | ios_base::in))
1359    this->clear();
1360  else
1361    this->setstate(ios_base::failbit);
1362}
1363
1364template <class _CharT, class _Traits>
1365inline
1366void
1367basic_ifstream<_CharT, _Traits>::close()
1368{
1369    if (__sb_.close() == 0)
1370        this->setstate(ios_base::failbit);
1371}
1372
1373// basic_ofstream
1374
1375template <class _CharT, class _Traits>
1376class _LIBCPP_TEMPLATE_VIS basic_ofstream
1377    : public basic_ostream<_CharT, _Traits>
1378{
1379public:
1380    typedef _CharT                         char_type;
1381    typedef _Traits                        traits_type;
1382    typedef typename traits_type::int_type int_type;
1383    typedef typename traits_type::pos_type pos_type;
1384    typedef typename traits_type::off_type off_type;
1385
1386    _LIBCPP_HIDE_FROM_ABI
1387    basic_ofstream();
1388    _LIBCPP_HIDE_FROM_ABI
1389    explicit basic_ofstream(const char* __s, ios_base::openmode __mode = ios_base::out);
1390#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1391    _LIBCPP_HIDE_FROM_ABI
1392    explicit basic_ofstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
1393#endif
1394    _LIBCPP_HIDE_FROM_ABI
1395    explicit basic_ofstream(const string& __s, ios_base::openmode __mode = ios_base::out);
1396
1397#if _LIBCPP_STD_VER >= 17
1398    _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI
1399    explicit basic_ofstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::out)
1400      : basic_ofstream(__p.c_str(), __mode) {}
1401#endif // _LIBCPP_STD_VER >= 17
1402
1403    _LIBCPP_HIDE_FROM_ABI
1404    basic_ofstream(basic_ofstream&& __rhs);
1405    _LIBCPP_HIDE_FROM_ABI
1406    basic_ofstream& operator=(basic_ofstream&& __rhs);
1407    _LIBCPP_HIDE_FROM_ABI
1408    void swap(basic_ofstream& __rhs);
1409
1410    _LIBCPP_HIDE_FROM_ABI
1411    basic_filebuf<char_type, traits_type>* rdbuf() const;
1412    _LIBCPP_HIDE_FROM_ABI
1413    bool is_open() const;
1414    void open(const char* __s, ios_base::openmode __mode = ios_base::out);
1415#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1416    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
1417#endif
1418    void open(const string& __s, ios_base::openmode __mode = ios_base::out);
1419
1420#if _LIBCPP_STD_VER >= 17
1421    _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI
1422    void open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::out)
1423    { return open(__p.c_str(), __mode); }
1424#endif // _LIBCPP_STD_VER >= 17
1425
1426    _LIBCPP_HIDE_FROM_ABI
1427    void __open(int __fd, ios_base::openmode __mode);
1428    _LIBCPP_HIDE_FROM_ABI
1429    void close();
1430
1431private:
1432    basic_filebuf<char_type, traits_type> __sb_;
1433};
1434
1435template <class _CharT, class _Traits>
1436inline
1437basic_ofstream<_CharT, _Traits>::basic_ofstream()
1438    : basic_ostream<char_type, traits_type>(&__sb_)
1439{
1440}
1441
1442template <class _CharT, class _Traits>
1443inline
1444basic_ofstream<_CharT, _Traits>::basic_ofstream(const char* __s, ios_base::openmode __mode)
1445    : basic_ostream<char_type, traits_type>(&__sb_)
1446{
1447    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1448        this->setstate(ios_base::failbit);
1449}
1450
1451#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1452template <class _CharT, class _Traits>
1453inline
1454basic_ofstream<_CharT, _Traits>::basic_ofstream(const wchar_t* __s, ios_base::openmode __mode)
1455    : basic_ostream<char_type, traits_type>(&__sb_)
1456{
1457    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1458        this->setstate(ios_base::failbit);
1459}
1460#endif
1461
1462template <class _CharT, class _Traits>
1463inline
1464basic_ofstream<_CharT, _Traits>::basic_ofstream(const string& __s, ios_base::openmode __mode)
1465    : basic_ostream<char_type, traits_type>(&__sb_)
1466{
1467    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1468        this->setstate(ios_base::failbit);
1469}
1470
1471template <class _CharT, class _Traits>
1472inline
1473basic_ofstream<_CharT, _Traits>::basic_ofstream(basic_ofstream&& __rhs)
1474    : basic_ostream<char_type, traits_type>(std::move(__rhs)),
1475      __sb_(std::move(__rhs.__sb_))
1476{
1477    this->set_rdbuf(&__sb_);
1478}
1479
1480template <class _CharT, class _Traits>
1481inline
1482basic_ofstream<_CharT, _Traits>&
1483basic_ofstream<_CharT, _Traits>::operator=(basic_ofstream&& __rhs)
1484{
1485    basic_ostream<char_type, traits_type>::operator=(std::move(__rhs));
1486    __sb_ = std::move(__rhs.__sb_);
1487    return *this;
1488}
1489
1490template <class _CharT, class _Traits>
1491inline
1492void
1493basic_ofstream<_CharT, _Traits>::swap(basic_ofstream& __rhs)
1494{
1495    basic_ostream<char_type, traits_type>::swap(__rhs);
1496    __sb_.swap(__rhs.__sb_);
1497}
1498
1499template <class _CharT, class _Traits>
1500inline _LIBCPP_HIDE_FROM_ABI
1501void
1502swap(basic_ofstream<_CharT, _Traits>& __x, basic_ofstream<_CharT, _Traits>& __y)
1503{
1504    __x.swap(__y);
1505}
1506
1507template <class _CharT, class _Traits>
1508inline
1509basic_filebuf<_CharT, _Traits>*
1510basic_ofstream<_CharT, _Traits>::rdbuf() const
1511{
1512    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1513}
1514
1515template <class _CharT, class _Traits>
1516inline
1517bool
1518basic_ofstream<_CharT, _Traits>::is_open() const
1519{
1520    return __sb_.is_open();
1521}
1522
1523template <class _CharT, class _Traits>
1524void
1525basic_ofstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
1526{
1527    if (__sb_.open(__s, __mode | ios_base::out))
1528        this->clear();
1529    else
1530        this->setstate(ios_base::failbit);
1531}
1532
1533#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1534template <class _CharT, class _Traits>
1535void
1536basic_ofstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
1537{
1538    if (__sb_.open(__s, __mode | ios_base::out))
1539        this->clear();
1540    else
1541        this->setstate(ios_base::failbit);
1542}
1543#endif
1544
1545template <class _CharT, class _Traits>
1546void
1547basic_ofstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
1548{
1549    if (__sb_.open(__s, __mode | ios_base::out))
1550        this->clear();
1551    else
1552        this->setstate(ios_base::failbit);
1553}
1554
1555template <class _CharT, class _Traits>
1556inline
1557void basic_ofstream<_CharT, _Traits>::__open(int __fd,
1558                                             ios_base::openmode __mode) {
1559  if (__sb_.__open(__fd, __mode | ios_base::out))
1560    this->clear();
1561  else
1562    this->setstate(ios_base::failbit);
1563}
1564
1565template <class _CharT, class _Traits>
1566inline
1567void
1568basic_ofstream<_CharT, _Traits>::close()
1569{
1570    if (__sb_.close() == nullptr)
1571        this->setstate(ios_base::failbit);
1572}
1573
1574// basic_fstream
1575
1576template <class _CharT, class _Traits>
1577class _LIBCPP_TEMPLATE_VIS basic_fstream
1578    : public basic_iostream<_CharT, _Traits>
1579{
1580public:
1581    typedef _CharT                         char_type;
1582    typedef _Traits                        traits_type;
1583    typedef typename traits_type::int_type int_type;
1584    typedef typename traits_type::pos_type pos_type;
1585    typedef typename traits_type::off_type off_type;
1586
1587    _LIBCPP_HIDE_FROM_ABI
1588    basic_fstream();
1589    _LIBCPP_HIDE_FROM_ABI
1590    explicit basic_fstream(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1591#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1592    _LIBCPP_HIDE_FROM_ABI
1593    explicit basic_fstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1594#endif
1595    _LIBCPP_HIDE_FROM_ABI
1596    explicit basic_fstream(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1597
1598#if _LIBCPP_STD_VER >= 17
1599    _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI
1600    explicit basic_fstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in | ios_base::out)
1601      : basic_fstream(__p.c_str(), __mode) {}
1602#endif // _LIBCPP_STD_VER >= 17
1603
1604    _LIBCPP_HIDE_FROM_ABI
1605    basic_fstream(basic_fstream&& __rhs);
1606
1607    _LIBCPP_HIDE_FROM_ABI
1608    basic_fstream& operator=(basic_fstream&& __rhs);
1609
1610    _LIBCPP_HIDE_FROM_ABI
1611    void swap(basic_fstream& __rhs);
1612
1613    _LIBCPP_HIDE_FROM_ABI
1614    basic_filebuf<char_type, traits_type>* rdbuf() const;
1615    _LIBCPP_HIDE_FROM_ABI
1616    bool is_open() const;
1617    _LIBCPP_HIDE_FROM_ABI void open(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1618#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1619    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1620#endif
1621    _LIBCPP_HIDE_FROM_ABI void open(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1622
1623#if _LIBCPP_STD_VER >= 17
1624    _LIBCPP_AVAILABILITY_FILESYSTEM_LIBRARY _LIBCPP_HIDE_FROM_ABI
1625    void open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in|ios_base::out)
1626    { return open(__p.c_str(), __mode); }
1627#endif // _LIBCPP_STD_VER >= 17
1628
1629    _LIBCPP_HIDE_FROM_ABI
1630    void close();
1631
1632private:
1633    basic_filebuf<char_type, traits_type> __sb_;
1634};
1635
1636template <class _CharT, class _Traits>
1637inline
1638basic_fstream<_CharT, _Traits>::basic_fstream()
1639    : basic_iostream<char_type, traits_type>(&__sb_)
1640{
1641}
1642
1643template <class _CharT, class _Traits>
1644inline
1645basic_fstream<_CharT, _Traits>::basic_fstream(const char* __s, ios_base::openmode __mode)
1646    : basic_iostream<char_type, traits_type>(&__sb_)
1647{
1648    if (__sb_.open(__s, __mode) == nullptr)
1649        this->setstate(ios_base::failbit);
1650}
1651
1652#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1653template <class _CharT, class _Traits>
1654inline
1655basic_fstream<_CharT, _Traits>::basic_fstream(const wchar_t* __s, ios_base::openmode __mode)
1656    : basic_iostream<char_type, traits_type>(&__sb_)
1657{
1658    if (__sb_.open(__s, __mode) == nullptr)
1659        this->setstate(ios_base::failbit);
1660}
1661#endif
1662
1663template <class _CharT, class _Traits>
1664inline
1665basic_fstream<_CharT, _Traits>::basic_fstream(const string& __s, ios_base::openmode __mode)
1666    : basic_iostream<char_type, traits_type>(&__sb_)
1667{
1668    if (__sb_.open(__s, __mode) == nullptr)
1669        this->setstate(ios_base::failbit);
1670}
1671
1672template <class _CharT, class _Traits>
1673inline
1674basic_fstream<_CharT, _Traits>::basic_fstream(basic_fstream&& __rhs)
1675    : basic_iostream<char_type, traits_type>(std::move(__rhs)),
1676      __sb_(std::move(__rhs.__sb_))
1677{
1678    this->set_rdbuf(&__sb_);
1679}
1680
1681template <class _CharT, class _Traits>
1682inline
1683basic_fstream<_CharT, _Traits>&
1684basic_fstream<_CharT, _Traits>::operator=(basic_fstream&& __rhs)
1685{
1686    basic_iostream<char_type, traits_type>::operator=(std::move(__rhs));
1687    __sb_ = std::move(__rhs.__sb_);
1688    return *this;
1689}
1690
1691template <class _CharT, class _Traits>
1692inline
1693void
1694basic_fstream<_CharT, _Traits>::swap(basic_fstream& __rhs)
1695{
1696    basic_iostream<char_type, traits_type>::swap(__rhs);
1697    __sb_.swap(__rhs.__sb_);
1698}
1699
1700template <class _CharT, class _Traits>
1701inline _LIBCPP_HIDE_FROM_ABI
1702void
1703swap(basic_fstream<_CharT, _Traits>& __x, basic_fstream<_CharT, _Traits>& __y)
1704{
1705    __x.swap(__y);
1706}
1707
1708template <class _CharT, class _Traits>
1709inline
1710basic_filebuf<_CharT, _Traits>*
1711basic_fstream<_CharT, _Traits>::rdbuf() const
1712{
1713    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1714}
1715
1716template <class _CharT, class _Traits>
1717inline
1718bool
1719basic_fstream<_CharT, _Traits>::is_open() const
1720{
1721    return __sb_.is_open();
1722}
1723
1724template <class _CharT, class _Traits>
1725void
1726basic_fstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
1727{
1728    if (__sb_.open(__s, __mode))
1729        this->clear();
1730    else
1731        this->setstate(ios_base::failbit);
1732}
1733
1734#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1735template <class _CharT, class _Traits>
1736void
1737basic_fstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
1738{
1739    if (__sb_.open(__s, __mode))
1740        this->clear();
1741    else
1742        this->setstate(ios_base::failbit);
1743}
1744#endif
1745
1746template <class _CharT, class _Traits>
1747void
1748basic_fstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
1749{
1750    if (__sb_.open(__s, __mode))
1751        this->clear();
1752    else
1753        this->setstate(ios_base::failbit);
1754}
1755
1756template <class _CharT, class _Traits>
1757inline
1758void
1759basic_fstream<_CharT, _Traits>::close()
1760{
1761    if (__sb_.close() == nullptr)
1762        this->setstate(ios_base::failbit);
1763}
1764
1765#if _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1
1766extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ifstream<char>;
1767extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ofstream<char>;
1768extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_filebuf<char>;
1769#endif
1770
1771_LIBCPP_END_NAMESPACE_STD
1772
1773#endif // _LIBCPP_HAS_NO_FILESYSTEM
1774
1775_LIBCPP_POP_MACROS
1776
1777#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1778#  include <atomic>
1779#  include <concepts>
1780#  include <cstdlib>
1781#  include <iosfwd>
1782#  include <limits>
1783#  include <mutex>
1784#  include <new>
1785#  include <stdexcept>
1786#  include <type_traits>
1787#endif
1788
1789#endif // _LIBCPP_FSTREAM
1790