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 <__locale>
187#include <__utility/move.h>
188#include <__utility/swap.h>
189#include <__utility/unreachable.h>
190#include <cstdio>
191#include <cstdlib>
192#include <cstring>
193#include <istream>
194#include <ostream>
195#include <typeinfo>
196#include <version>
197
198#if !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
199#   include <filesystem>
200#endif
201
202#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
203#  pragma GCC system_header
204#endif
205
206_LIBCPP_PUSH_MACROS
207#include <__undef_macros>
208
209#if defined(_LIBCPP_MSVCRT) || defined(_NEWLIB_VERSION)
210#  define _LIBCPP_HAS_NO_OFF_T_FUNCTIONS
211#endif
212
213#if !defined(_LIBCPP_HAS_NO_FSTREAM)
214
215_LIBCPP_BEGIN_NAMESPACE_STD
216
217template <class _CharT, class _Traits>
218class _LIBCPP_TEMPLATE_VIS basic_filebuf
219    : public basic_streambuf<_CharT, _Traits>
220{
221public:
222    typedef _CharT                           char_type;
223    typedef _Traits                          traits_type;
224    typedef typename traits_type::int_type   int_type;
225    typedef typename traits_type::pos_type   pos_type;
226    typedef typename traits_type::off_type   off_type;
227    typedef typename traits_type::state_type state_type;
228
229    // 27.9.1.2 Constructors/destructor:
230    basic_filebuf();
231    basic_filebuf(basic_filebuf&& __rhs);
232    ~basic_filebuf() override;
233
234    // 27.9.1.3 Assign/swap:
235    _LIBCPP_INLINE_VISIBILITY
236    basic_filebuf& operator=(basic_filebuf&& __rhs);
237    void swap(basic_filebuf& __rhs);
238
239    // 27.9.1.4 Members:
240    _LIBCPP_INLINE_VISIBILITY
241    bool is_open() const;
242    basic_filebuf* open(const char* __s, ios_base::openmode __mode);
243#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
244    basic_filebuf* open(const wchar_t* __s, ios_base::openmode __mode);
245#endif
246    _LIBCPP_INLINE_VISIBILITY
247    basic_filebuf* open(const string& __s, ios_base::openmode __mode);
248
249#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
250    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
251    basic_filebuf* open(const _VSTD_FS::path& __p, ios_base::openmode __mode) {
252      return open(__p.c_str(), __mode);
253    }
254#endif
255    _LIBCPP_INLINE_VISIBILITY
256    basic_filebuf* __open(int __fd, ios_base::openmode __mode);
257    basic_filebuf* close();
258
259    _LIBCPP_INLINE_VISIBILITY
260    inline static const char*
261    __make_mdstring(ios_base::openmode __mode) _NOEXCEPT;
262
263  protected:
264    // 27.9.1.5 Overridden virtual functions:
265    int_type underflow() override;
266    int_type pbackfail(int_type __c = traits_type::eof()) override;
267    int_type overflow (int_type __c = traits_type::eof()) override;
268    basic_streambuf<char_type, traits_type>* setbuf(char_type* __s, streamsize __n) override;
269    pos_type seekoff(off_type __off, ios_base::seekdir __way,
270                     ios_base::openmode __wch = ios_base::in | ios_base::out) override;
271    pos_type seekpos(pos_type __sp,
272                     ios_base::openmode __wch = ios_base::in | ios_base::out) override;
273    int sync() override;
274    void imbue(const locale& __loc) override;
275
276private:
277  char* __extbuf_;
278  const char* __extbufnext_;
279  const char* __extbufend_;
280  char __extbuf_min_[8];
281  size_t __ebs_;
282  char_type* __intbuf_;
283  size_t __ibs_;
284  FILE* __file_;
285  const codecvt<char_type, char, state_type>* __cv_;
286  state_type __st_;
287  state_type __st_last_;
288  ios_base::openmode __om_;
289  ios_base::openmode __cm_;
290  bool __owns_eb_;
291  bool __owns_ib_;
292  bool __always_noconv_;
293
294  bool __read_mode();
295  void __write_mode();
296};
297
298template <class _CharT, class _Traits>
299basic_filebuf<_CharT, _Traits>::basic_filebuf()
300    : __extbuf_(nullptr),
301      __extbufnext_(nullptr),
302      __extbufend_(nullptr),
303      __ebs_(0),
304      __intbuf_(nullptr),
305      __ibs_(0),
306      __file_(nullptr),
307      __cv_(nullptr),
308      __st_(),
309      __st_last_(),
310      __om_(0),
311      __cm_(0),
312      __owns_eb_(false),
313      __owns_ib_(false),
314      __always_noconv_(false)
315{
316    if (std::has_facet<codecvt<char_type, char, state_type> >(this->getloc()))
317    {
318        __cv_ = &std::use_facet<codecvt<char_type, char, state_type> >(this->getloc());
319        __always_noconv_ = __cv_->always_noconv();
320    }
321    setbuf(nullptr, 4096);
322}
323
324template <class _CharT, class _Traits>
325basic_filebuf<_CharT, _Traits>::basic_filebuf(basic_filebuf&& __rhs)
326    : basic_streambuf<_CharT, _Traits>(__rhs)
327{
328    if (__rhs.__extbuf_ == __rhs.__extbuf_min_)
329    {
330        __extbuf_ = __extbuf_min_;
331        __extbufnext_ = __extbuf_ + (__rhs.__extbufnext_ - __rhs.__extbuf_);
332        __extbufend_ = __extbuf_ + (__rhs.__extbufend_ - __rhs.__extbuf_);
333    }
334    else
335    {
336        __extbuf_ = __rhs.__extbuf_;
337        __extbufnext_ = __rhs.__extbufnext_;
338        __extbufend_ = __rhs.__extbufend_;
339    }
340    __ebs_ = __rhs.__ebs_;
341    __intbuf_ = __rhs.__intbuf_;
342    __ibs_ = __rhs.__ibs_;
343    __file_ = __rhs.__file_;
344    __cv_ = __rhs.__cv_;
345    __st_ = __rhs.__st_;
346    __st_last_ = __rhs.__st_last_;
347    __om_ = __rhs.__om_;
348    __cm_ = __rhs.__cm_;
349    __owns_eb_ = __rhs.__owns_eb_;
350    __owns_ib_ = __rhs.__owns_ib_;
351    __always_noconv_ = __rhs.__always_noconv_;
352    if (__rhs.pbase())
353    {
354        if (__rhs.pbase() == __rhs.__intbuf_)
355            this->setp(__intbuf_, __intbuf_ + (__rhs. epptr() - __rhs.pbase()));
356        else
357            this->setp((char_type*)__extbuf_,
358                       (char_type*)__extbuf_ + (__rhs. epptr() - __rhs.pbase()));
359        this->__pbump(__rhs. pptr() - __rhs.pbase());
360    }
361    else if (__rhs.eback())
362    {
363        if (__rhs.eback() == __rhs.__intbuf_)
364            this->setg(__intbuf_, __intbuf_ + (__rhs.gptr() - __rhs.eback()),
365                                  __intbuf_ + (__rhs.egptr() - __rhs.eback()));
366        else
367            this->setg((char_type*)__extbuf_,
368                       (char_type*)__extbuf_ + (__rhs.gptr() - __rhs.eback()),
369                       (char_type*)__extbuf_ + (__rhs.egptr() - __rhs.eback()));
370    }
371    __rhs.__extbuf_ = nullptr;
372    __rhs.__extbufnext_ = nullptr;
373    __rhs.__extbufend_ = nullptr;
374    __rhs.__ebs_ = 0;
375    __rhs.__intbuf_ = 0;
376    __rhs.__ibs_ = 0;
377    __rhs.__file_ = nullptr;
378    __rhs.__st_ = state_type();
379    __rhs.__st_last_ = state_type();
380    __rhs.__om_ = 0;
381    __rhs.__cm_ = 0;
382    __rhs.__owns_eb_ = false;
383    __rhs.__owns_ib_ = false;
384    __rhs.setg(0, 0, 0);
385    __rhs.setp(0, 0);
386}
387
388template <class _CharT, class _Traits>
389inline
390basic_filebuf<_CharT, _Traits>&
391basic_filebuf<_CharT, _Traits>::operator=(basic_filebuf&& __rhs)
392{
393    close();
394    swap(__rhs);
395    return *this;
396}
397
398template <class _CharT, class _Traits>
399basic_filebuf<_CharT, _Traits>::~basic_filebuf()
400{
401#ifndef _LIBCPP_NO_EXCEPTIONS
402    try
403    {
404#endif // _LIBCPP_NO_EXCEPTIONS
405        close();
406#ifndef _LIBCPP_NO_EXCEPTIONS
407    }
408    catch (...)
409    {
410    }
411#endif // _LIBCPP_NO_EXCEPTIONS
412    if (__owns_eb_)
413        delete [] __extbuf_;
414    if (__owns_ib_)
415        delete [] __intbuf_;
416}
417
418template <class _CharT, class _Traits>
419void
420basic_filebuf<_CharT, _Traits>::swap(basic_filebuf& __rhs)
421{
422    basic_streambuf<char_type, traits_type>::swap(__rhs);
423    if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_)
424    {
425        // Neither *this nor __rhs uses the small buffer, so we can simply swap the pointers.
426        std::swap(__extbuf_, __rhs.__extbuf_);
427        std::swap(__extbufnext_, __rhs.__extbufnext_);
428        std::swap(__extbufend_, __rhs.__extbufend_);
429    }
430    else
431    {
432        ptrdiff_t __ln = __extbufnext_       ? __extbufnext_ - __extbuf_             : 0;
433        ptrdiff_t __le = __extbufend_        ? __extbufend_ - __extbuf_              : 0;
434        ptrdiff_t __rn = __rhs.__extbufnext_ ? __rhs.__extbufnext_ - __rhs.__extbuf_ : 0;
435        ptrdiff_t __re = __rhs.__extbufend_  ? __rhs.__extbufend_ - __rhs.__extbuf_  : 0;
436        if (__extbuf_ == __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_)
437        {
438            // *this uses the small buffer, but __rhs doesn't.
439            __extbuf_ = __rhs.__extbuf_;
440            __rhs.__extbuf_ = __rhs.__extbuf_min_;
441            std::memmove(__rhs.__extbuf_min_, __extbuf_min_, sizeof(__extbuf_min_));
442        }
443        else if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ == __rhs.__extbuf_min_)
444        {
445            // *this doesn't use the small buffer, but __rhs does.
446            __rhs.__extbuf_ = __extbuf_;
447            __extbuf_ = __extbuf_min_;
448            std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));
449        }
450        else
451        {
452            // Both *this and __rhs use the small buffer.
453            char __tmp[sizeof(__extbuf_min_)];
454            std::memmove(__tmp, __extbuf_min_, sizeof(__extbuf_min_));
455            std::memmove(__extbuf_min_, __rhs.__extbuf_min_, sizeof(__extbuf_min_));
456            std::memmove(__rhs.__extbuf_min_, __tmp, sizeof(__extbuf_min_));
457        }
458        __extbufnext_ = __extbuf_ + __rn;
459        __extbufend_ = __extbuf_ + __re;
460        __rhs.__extbufnext_ = __rhs.__extbuf_ + __ln;
461        __rhs.__extbufend_ = __rhs.__extbuf_ + __le;
462    }
463    _VSTD::swap(__ebs_, __rhs.__ebs_);
464    _VSTD::swap(__intbuf_, __rhs.__intbuf_);
465    _VSTD::swap(__ibs_, __rhs.__ibs_);
466    _VSTD::swap(__file_, __rhs.__file_);
467    _VSTD::swap(__cv_, __rhs.__cv_);
468    _VSTD::swap(__st_, __rhs.__st_);
469    _VSTD::swap(__st_last_, __rhs.__st_last_);
470    _VSTD::swap(__om_, __rhs.__om_);
471    _VSTD::swap(__cm_, __rhs.__cm_);
472    _VSTD::swap(__owns_eb_, __rhs.__owns_eb_);
473    _VSTD::swap(__owns_ib_, __rhs.__owns_ib_);
474    _VSTD::swap(__always_noconv_, __rhs.__always_noconv_);
475    if (this->eback() == (char_type*)__rhs.__extbuf_min_)
476    {
477        ptrdiff_t __n = this->gptr() - this->eback();
478        ptrdiff_t __e = this->egptr() - this->eback();
479        this->setg((char_type*)__extbuf_min_,
480                   (char_type*)__extbuf_min_ + __n,
481                   (char_type*)__extbuf_min_ + __e);
482    }
483    else if (this->pbase() == (char_type*)__rhs.__extbuf_min_)
484    {
485        ptrdiff_t __n = this->pptr() - this->pbase();
486        ptrdiff_t __e = this->epptr() - this->pbase();
487        this->setp((char_type*)__extbuf_min_,
488                   (char_type*)__extbuf_min_ + __e);
489        this->__pbump(__n);
490    }
491    if (__rhs.eback() == (char_type*)__extbuf_min_)
492    {
493        ptrdiff_t __n = __rhs.gptr() - __rhs.eback();
494        ptrdiff_t __e = __rhs.egptr() - __rhs.eback();
495        __rhs.setg((char_type*)__rhs.__extbuf_min_,
496                   (char_type*)__rhs.__extbuf_min_ + __n,
497                   (char_type*)__rhs.__extbuf_min_ + __e);
498    }
499    else if (__rhs.pbase() == (char_type*)__extbuf_min_)
500    {
501        ptrdiff_t __n = __rhs.pptr() - __rhs.pbase();
502        ptrdiff_t __e = __rhs.epptr() - __rhs.pbase();
503        __rhs.setp((char_type*)__rhs.__extbuf_min_,
504                   (char_type*)__rhs.__extbuf_min_ + __e);
505        __rhs.__pbump(__n);
506    }
507}
508
509template <class _CharT, class _Traits>
510inline _LIBCPP_INLINE_VISIBILITY
511void
512swap(basic_filebuf<_CharT, _Traits>& __x, basic_filebuf<_CharT, _Traits>& __y)
513{
514    __x.swap(__y);
515}
516
517template <class _CharT, class _Traits>
518inline
519bool
520basic_filebuf<_CharT, _Traits>::is_open() const
521{
522    return __file_ != nullptr;
523}
524
525template <class _CharT, class _Traits>
526const char* basic_filebuf<_CharT, _Traits>::__make_mdstring(
527    ios_base::openmode __mode) _NOEXCEPT {
528  switch (__mode & ~ios_base::ate) {
529  case ios_base::out:
530  case ios_base::out | ios_base::trunc:
531    return "w" _LIBCPP_FOPEN_CLOEXEC_MODE;
532  case ios_base::out | ios_base::app:
533  case ios_base::app:
534    return "a" _LIBCPP_FOPEN_CLOEXEC_MODE;
535  case ios_base::in:
536    return "r" _LIBCPP_FOPEN_CLOEXEC_MODE;
537  case ios_base::in | ios_base::out:
538    return "r+" _LIBCPP_FOPEN_CLOEXEC_MODE;
539  case ios_base::in | ios_base::out | ios_base::trunc:
540    return "w+" _LIBCPP_FOPEN_CLOEXEC_MODE;
541  case ios_base::in | ios_base::out | ios_base::app:
542  case ios_base::in | ios_base::app:
543    return "a+" _LIBCPP_FOPEN_CLOEXEC_MODE;
544  case ios_base::out | ios_base::binary:
545  case ios_base::out | ios_base::trunc | ios_base::binary:
546    return "wb" _LIBCPP_FOPEN_CLOEXEC_MODE;
547  case ios_base::out | ios_base::app | ios_base::binary:
548  case ios_base::app | ios_base::binary:
549    return "ab" _LIBCPP_FOPEN_CLOEXEC_MODE;
550  case ios_base::in | ios_base::binary:
551    return "rb" _LIBCPP_FOPEN_CLOEXEC_MODE;
552  case ios_base::in | ios_base::out | ios_base::binary:
553    return "r+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
554  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
555    return "w+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
556  case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
557  case ios_base::in | ios_base::app | ios_base::binary:
558    return "a+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
559  default:
560    return nullptr;
561  }
562  __libcpp_unreachable();
563}
564
565template <class _CharT, class _Traits>
566basic_filebuf<_CharT, _Traits>*
567basic_filebuf<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
568{
569    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
570    if (__file_ == nullptr)
571    {
572      if (const char* __mdstr = __make_mdstring(__mode)) {
573        __rt = this;
574        __file_ = fopen(__s, __mdstr);
575        if (__file_) {
576          __om_ = __mode;
577          if (__mode & ios_base::ate) {
578            if (fseek(__file_, 0, SEEK_END)) {
579              fclose(__file_);
580              __file_ = nullptr;
581              __rt = nullptr;
582            }
583          }
584        } else
585          __rt = nullptr;
586      }
587    }
588    return __rt;
589}
590
591template <class _CharT, class _Traits>
592inline
593basic_filebuf<_CharT, _Traits>*
594basic_filebuf<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
595  basic_filebuf<_CharT, _Traits>* __rt = nullptr;
596  if (__file_ == nullptr) {
597    if (const char* __mdstr = __make_mdstring(__mode)) {
598      __rt = this;
599      __file_ = fdopen(__fd, __mdstr);
600      if (__file_) {
601        __om_ = __mode;
602        if (__mode & ios_base::ate) {
603          if (fseek(__file_, 0, SEEK_END)) {
604            fclose(__file_);
605            __file_ = nullptr;
606            __rt = nullptr;
607          }
608        }
609      } else
610        __rt = nullptr;
611    }
612  }
613  return __rt;
614}
615
616#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
617// This is basically the same as the char* overload except that it uses _wfopen
618// and long mode strings.
619template <class _CharT, class _Traits>
620basic_filebuf<_CharT, _Traits>*
621basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
622{
623    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
624    if (__file_ == nullptr)
625    {
626        __rt = this;
627        const wchar_t* __mdstr;
628        switch (__mode & ~ios_base::ate)
629        {
630        case ios_base::out:
631        case ios_base::out | ios_base::trunc:
632            __mdstr = L"w";
633            break;
634        case ios_base::out | ios_base::app:
635        case ios_base::app:
636            __mdstr = L"a";
637            break;
638        case ios_base::in:
639            __mdstr = L"r";
640            break;
641        case ios_base::in | ios_base::out:
642            __mdstr = L"r+";
643            break;
644        case ios_base::in | ios_base::out | ios_base::trunc:
645            __mdstr = L"w+";
646            break;
647        case ios_base::in | ios_base::out | ios_base::app:
648        case ios_base::in | ios_base::app:
649            __mdstr = L"a+";
650            break;
651        case ios_base::out | ios_base::binary:
652        case ios_base::out | ios_base::trunc | ios_base::binary:
653            __mdstr = L"wb";
654            break;
655        case ios_base::out | ios_base::app | ios_base::binary:
656        case ios_base::app | ios_base::binary:
657            __mdstr = L"ab";
658            break;
659        case ios_base::in | ios_base::binary:
660            __mdstr = L"rb";
661            break;
662        case ios_base::in | ios_base::out | ios_base::binary:
663            __mdstr = L"r+b";
664            break;
665        case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
666            __mdstr = L"w+b";
667            break;
668        case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
669        case ios_base::in | ios_base::app | ios_base::binary:
670            __mdstr = L"a+b";
671            break;
672        default:
673            __rt = nullptr;
674            break;
675        }
676        if (__rt)
677        {
678            __file_ = _wfopen(__s, __mdstr);
679            if (__file_)
680            {
681                __om_ = __mode;
682                if (__mode & ios_base::ate)
683                {
684                    if (fseek(__file_, 0, SEEK_END))
685                    {
686                        fclose(__file_);
687                        __file_ = nullptr;
688                        __rt = nullptr;
689                    }
690                }
691            }
692            else
693                __rt = nullptr;
694        }
695    }
696    return __rt;
697}
698#endif
699
700template <class _CharT, class _Traits>
701inline
702basic_filebuf<_CharT, _Traits>*
703basic_filebuf<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
704{
705    return open(__s.c_str(), __mode);
706}
707
708template <class _CharT, class _Traits>
709basic_filebuf<_CharT, _Traits>*
710basic_filebuf<_CharT, _Traits>::close()
711{
712    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
713    if (__file_)
714    {
715        __rt = this;
716        unique_ptr<FILE, int(*)(FILE*)> __h(__file_, fclose);
717        if (sync())
718            __rt = nullptr;
719        if (fclose(__h.release()))
720            __rt = nullptr;
721        __file_ = nullptr;
722        setbuf(0, 0);
723    }
724    return __rt;
725}
726
727template <class _CharT, class _Traits>
728typename basic_filebuf<_CharT, _Traits>::int_type
729basic_filebuf<_CharT, _Traits>::underflow()
730{
731    if (__file_ == nullptr)
732        return traits_type::eof();
733    bool __initial = __read_mode();
734    char_type __1buf;
735    if (this->gptr() == nullptr)
736        this->setg(&__1buf, &__1buf+1, &__1buf+1);
737    const size_t __unget_sz = __initial ? 0 : std::min<size_t>((this->egptr() - this->eback()) / 2, 4);
738    int_type __c = traits_type::eof();
739    if (this->gptr() == this->egptr())
740    {
741        _VSTD::memmove(this->eback(), this->egptr() - __unget_sz, __unget_sz * sizeof(char_type));
742        if (__always_noconv_)
743        {
744            size_t __nmemb = static_cast<size_t>(this->egptr() - this->eback() - __unget_sz);
745            __nmemb = ::fread(this->eback() + __unget_sz, 1, __nmemb, __file_);
746            if (__nmemb != 0)
747            {
748                this->setg(this->eback(),
749                           this->eback() + __unget_sz,
750                           this->eback() + __unget_sz + __nmemb);
751                __c = traits_type::to_int_type(*this->gptr());
752            }
753        }
754        else
755        {
756            if (__extbufend_ != __extbufnext_) {
757                _LIBCPP_ASSERT(__extbufnext_ != nullptr, "underflow moving from nullptr");
758                _LIBCPP_ASSERT(__extbuf_ != nullptr, "underflow moving into nullptr");
759                _VSTD::memmove(__extbuf_, __extbufnext_, __extbufend_ - __extbufnext_);
760            }
761            __extbufnext_ = __extbuf_ + (__extbufend_ - __extbufnext_);
762            __extbufend_ = __extbuf_ + (__extbuf_ == __extbuf_min_ ? sizeof(__extbuf_min_) : __ebs_);
763            size_t __nmemb = _VSTD::min(static_cast<size_t>(__ibs_ - __unget_sz),
764                                 static_cast<size_t>(__extbufend_ - __extbufnext_));
765            codecvt_base::result __r;
766            __st_last_ = __st_;
767            size_t __nr = fread((void*) const_cast<char *>(__extbufnext_), 1, __nmemb, __file_);
768            if (__nr != 0)
769            {
770                if (!__cv_)
771                    __throw_bad_cast();
772
773                __extbufend_ = __extbufnext_ + __nr;
774                char_type*  __inext;
775                __r = __cv_->in(__st_, __extbuf_, __extbufend_, __extbufnext_,
776                                       this->eback() + __unget_sz,
777                                       this->eback() + __ibs_, __inext);
778                if (__r == codecvt_base::noconv)
779                {
780                    this->setg((char_type*)__extbuf_, (char_type*)__extbuf_,
781                                          (char_type*)const_cast<char *>(__extbufend_));
782                    __c = traits_type::to_int_type(*this->gptr());
783                }
784                else if (__inext != this->eback() + __unget_sz)
785                {
786                    this->setg(this->eback(), this->eback() + __unget_sz, __inext);
787                    __c = traits_type::to_int_type(*this->gptr());
788                }
789            }
790        }
791    }
792    else
793        __c = traits_type::to_int_type(*this->gptr());
794    if (this->eback() == &__1buf)
795        this->setg(nullptr, nullptr, nullptr);
796    return __c;
797}
798
799template <class _CharT, class _Traits>
800typename basic_filebuf<_CharT, _Traits>::int_type
801basic_filebuf<_CharT, _Traits>::pbackfail(int_type __c)
802{
803    if (__file_ && this->eback() < this->gptr())
804    {
805        if (traits_type::eq_int_type(__c, traits_type::eof()))
806        {
807            this->gbump(-1);
808            return traits_type::not_eof(__c);
809        }
810        if ((__om_ & ios_base::out) ||
811            traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1]))
812        {
813            this->gbump(-1);
814            *this->gptr() = traits_type::to_char_type(__c);
815            return __c;
816        }
817    }
818    return traits_type::eof();
819}
820
821template <class _CharT, class _Traits>
822typename basic_filebuf<_CharT, _Traits>::int_type
823basic_filebuf<_CharT, _Traits>::overflow(int_type __c)
824{
825    if (__file_ == nullptr)
826        return traits_type::eof();
827    __write_mode();
828    char_type __1buf;
829    char_type* __pb_save = this->pbase();
830    char_type* __epb_save = this->epptr();
831    if (!traits_type::eq_int_type(__c, traits_type::eof()))
832    {
833        if (this->pptr() == nullptr)
834            this->setp(&__1buf, &__1buf+1);
835        *this->pptr() = traits_type::to_char_type(__c);
836        this->pbump(1);
837    }
838    if (this->pptr() != this->pbase())
839    {
840        if (__always_noconv_)
841        {
842            size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
843            if (std::fwrite(this->pbase(), sizeof(char_type), __nmemb, __file_) != __nmemb)
844                return traits_type::eof();
845        }
846        else
847        {
848            char* __extbe = __extbuf_;
849            codecvt_base::result __r;
850            do
851            {
852                if (!__cv_)
853                    __throw_bad_cast();
854
855                const char_type* __e;
856                __r = __cv_->out(__st_, this->pbase(), this->pptr(), __e,
857                                        __extbuf_, __extbuf_ + __ebs_, __extbe);
858                if (__e == this->pbase())
859                    return traits_type::eof();
860                if (__r == codecvt_base::noconv)
861                {
862                    size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
863                    if (std::fwrite(this->pbase(), 1, __nmemb, __file_) != __nmemb)
864                        return traits_type::eof();
865                }
866                else if (__r == codecvt_base::ok || __r == codecvt_base::partial)
867                {
868                    size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
869                    if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
870                        return traits_type::eof();
871                    if (__r == codecvt_base::partial)
872                    {
873                        this->setp(const_cast<char_type*>(__e), this->pptr());
874                        this->__pbump(this->epptr() - this->pbase());
875                    }
876                }
877                else
878                    return traits_type::eof();
879            } while (__r == codecvt_base::partial);
880        }
881        this->setp(__pb_save, __epb_save);
882    }
883    return traits_type::not_eof(__c);
884}
885
886template <class _CharT, class _Traits>
887basic_streambuf<_CharT, _Traits>*
888basic_filebuf<_CharT, _Traits>::setbuf(char_type* __s, streamsize __n)
889{
890    this->setg(nullptr, nullptr, nullptr);
891    this->setp(nullptr, nullptr);
892    if (__owns_eb_)
893        delete [] __extbuf_;
894    if (__owns_ib_)
895        delete [] __intbuf_;
896    __ebs_ = __n;
897    if (__ebs_ > sizeof(__extbuf_min_))
898    {
899        if (__always_noconv_ && __s)
900        {
901            __extbuf_ = (char*)__s;
902            __owns_eb_ = false;
903        }
904        else
905        {
906            __extbuf_ = new char[__ebs_];
907            __owns_eb_ = true;
908        }
909    }
910    else
911    {
912        __extbuf_ = __extbuf_min_;
913        __ebs_ = sizeof(__extbuf_min_);
914        __owns_eb_ = false;
915    }
916    if (!__always_noconv_)
917    {
918        __ibs_ = max<streamsize>(__n, sizeof(__extbuf_min_));
919        if (__s && __ibs_ >= sizeof(__extbuf_min_))
920        {
921            __intbuf_ = __s;
922            __owns_ib_ = false;
923        }
924        else
925        {
926            __intbuf_ = new char_type[__ibs_];
927            __owns_ib_ = true;
928        }
929    }
930    else
931    {
932        __ibs_ = 0;
933        __intbuf_ = nullptr;
934        __owns_ib_ = false;
935    }
936    return this;
937}
938
939template <class _CharT, class _Traits>
940typename basic_filebuf<_CharT, _Traits>::pos_type
941basic_filebuf<_CharT, _Traits>::seekoff(off_type __off, ios_base::seekdir __way,
942                                        ios_base::openmode)
943{
944    if (!__cv_)
945        __throw_bad_cast();
946
947    int __width = __cv_->encoding();
948    if (__file_ == nullptr || (__width <= 0 && __off != 0) || sync())
949        return pos_type(off_type(-1));
950    // __width > 0 || __off == 0
951    int __whence;
952    switch (__way)
953    {
954    case ios_base::beg:
955        __whence = SEEK_SET;
956        break;
957    case ios_base::cur:
958        __whence = SEEK_CUR;
959        break;
960    case ios_base::end:
961        __whence = SEEK_END;
962        break;
963    default:
964        return pos_type(off_type(-1));
965    }
966#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
967    if (fseek(__file_, __width > 0 ? __width * __off : 0, __whence))
968        return pos_type(off_type(-1));
969    pos_type __r = ftell(__file_);
970#else
971    if (::fseeko(__file_, __width > 0 ? __width * __off : 0, __whence))
972        return pos_type(off_type(-1));
973    pos_type __r = ftello(__file_);
974#endif
975    __r.state(__st_);
976    return __r;
977}
978
979template <class _CharT, class _Traits>
980typename basic_filebuf<_CharT, _Traits>::pos_type
981basic_filebuf<_CharT, _Traits>::seekpos(pos_type __sp, ios_base::openmode)
982{
983    if (__file_ == nullptr || sync())
984        return pos_type(off_type(-1));
985#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
986    if (fseek(__file_, __sp, SEEK_SET))
987        return pos_type(off_type(-1));
988#else
989    if (::fseeko(__file_, __sp, SEEK_SET))
990        return pos_type(off_type(-1));
991#endif
992    __st_ = __sp.state();
993    return __sp;
994}
995
996template <class _CharT, class _Traits>
997int
998basic_filebuf<_CharT, _Traits>::sync()
999{
1000    if (__file_ == nullptr)
1001        return 0;
1002    if (!__cv_)
1003        __throw_bad_cast();
1004
1005    if (__cm_ & ios_base::out)
1006    {
1007        if (this->pptr() != this->pbase())
1008            if (overflow() == traits_type::eof())
1009                return -1;
1010        codecvt_base::result __r;
1011        do
1012        {
1013            char* __extbe;
1014            __r = __cv_->unshift(__st_, __extbuf_, __extbuf_ + __ebs_, __extbe);
1015            size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
1016            if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
1017                return -1;
1018        } while (__r == codecvt_base::partial);
1019        if (__r == codecvt_base::error)
1020            return -1;
1021        if (fflush(__file_))
1022            return -1;
1023    }
1024    else if (__cm_ & ios_base::in)
1025    {
1026        off_type __c;
1027        state_type __state = __st_last_;
1028        bool __update_st = false;
1029        if (__always_noconv_)
1030            __c = this->egptr() - this->gptr();
1031        else
1032        {
1033            int __width = __cv_->encoding();
1034            __c = __extbufend_ - __extbufnext_;
1035            if (__width > 0)
1036                __c += __width * (this->egptr() - this->gptr());
1037            else
1038            {
1039                if (this->gptr() != this->egptr())
1040                {
1041                    const int __off =  __cv_->length(__state, __extbuf_,
1042                                                     __extbufnext_,
1043                                                     this->gptr() - this->eback());
1044                    __c += __extbufnext_ - __extbuf_ - __off;
1045                    __update_st = true;
1046                }
1047            }
1048        }
1049#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
1050        if (fseek(__file_, -__c, SEEK_CUR))
1051            return -1;
1052#else
1053        if (::fseeko(__file_, -__c, SEEK_CUR))
1054            return -1;
1055#endif
1056        if (__update_st)
1057            __st_ = __state;
1058        __extbufnext_ = __extbufend_ = __extbuf_;
1059        this->setg(nullptr, nullptr, nullptr);
1060        __cm_ = 0;
1061    }
1062    return 0;
1063}
1064
1065template <class _CharT, class _Traits>
1066void
1067basic_filebuf<_CharT, _Traits>::imbue(const locale& __loc)
1068{
1069    sync();
1070    __cv_ = &std::use_facet<codecvt<char_type, char, state_type> >(__loc);
1071    bool __old_anc = __always_noconv_;
1072    __always_noconv_ = __cv_->always_noconv();
1073    if (__old_anc != __always_noconv_)
1074    {
1075        this->setg(nullptr, nullptr, nullptr);
1076        this->setp(nullptr, nullptr);
1077        // invariant, char_type is char, else we couldn't get here
1078        if (__always_noconv_)  // need to dump __intbuf_
1079        {
1080            if (__owns_eb_)
1081                delete [] __extbuf_;
1082            __owns_eb_ = __owns_ib_;
1083            __ebs_ = __ibs_;
1084            __extbuf_ = (char*)__intbuf_;
1085            __ibs_ = 0;
1086            __intbuf_ = nullptr;
1087            __owns_ib_ = false;
1088        }
1089        else  // need to obtain an __intbuf_.
1090        {     // If __extbuf_ is user-supplied, use it, else new __intbuf_
1091            if (!__owns_eb_ && __extbuf_ != __extbuf_min_)
1092            {
1093                __ibs_ = __ebs_;
1094                __intbuf_ = (char_type*)__extbuf_;
1095                __owns_ib_ = false;
1096                __extbuf_ = new char[__ebs_];
1097                __owns_eb_ = true;
1098            }
1099            else
1100            {
1101                __ibs_ = __ebs_;
1102                __intbuf_ = new char_type[__ibs_];
1103                __owns_ib_ = true;
1104            }
1105        }
1106    }
1107}
1108
1109template <class _CharT, class _Traits>
1110bool
1111basic_filebuf<_CharT, _Traits>::__read_mode()
1112{
1113    if (!(__cm_ & ios_base::in))
1114    {
1115        this->setp(nullptr, nullptr);
1116        if (__always_noconv_)
1117            this->setg((char_type*)__extbuf_,
1118                       (char_type*)__extbuf_ + __ebs_,
1119                       (char_type*)__extbuf_ + __ebs_);
1120        else
1121            this->setg(__intbuf_, __intbuf_ + __ibs_, __intbuf_ + __ibs_);
1122        __cm_ = ios_base::in;
1123        return true;
1124    }
1125    return false;
1126}
1127
1128template <class _CharT, class _Traits>
1129void
1130basic_filebuf<_CharT, _Traits>::__write_mode()
1131{
1132    if (!(__cm_ & ios_base::out))
1133    {
1134        this->setg(nullptr, nullptr, nullptr);
1135        if (__ebs_ > sizeof(__extbuf_min_))
1136        {
1137            if (__always_noconv_)
1138                this->setp((char_type*)__extbuf_,
1139                           (char_type*)__extbuf_ + (__ebs_ - 1));
1140            else
1141                this->setp(__intbuf_, __intbuf_ + (__ibs_ - 1));
1142        }
1143        else
1144            this->setp(nullptr, nullptr);
1145        __cm_ = ios_base::out;
1146    }
1147}
1148
1149// basic_ifstream
1150
1151template <class _CharT, class _Traits>
1152class _LIBCPP_TEMPLATE_VIS basic_ifstream
1153    : public basic_istream<_CharT, _Traits>
1154{
1155public:
1156    typedef _CharT                         char_type;
1157    typedef _Traits                        traits_type;
1158    typedef typename traits_type::int_type int_type;
1159    typedef typename traits_type::pos_type pos_type;
1160    typedef typename traits_type::off_type off_type;
1161
1162    _LIBCPP_INLINE_VISIBILITY
1163    basic_ifstream();
1164    _LIBCPP_INLINE_VISIBILITY
1165    explicit basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in);
1166#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1167    _LIBCPP_INLINE_VISIBILITY
1168    explicit basic_ifstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
1169#endif
1170    _LIBCPP_INLINE_VISIBILITY
1171    explicit basic_ifstream(const string& __s, ios_base::openmode __mode = ios_base::in);
1172#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
1173    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
1174    explicit basic_ifstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in)
1175      : basic_ifstream(__p.c_str(), __mode) {}
1176#endif // _LIBCPP_STD_VER >= 17
1177    _LIBCPP_INLINE_VISIBILITY
1178    basic_ifstream(basic_ifstream&& __rhs);
1179    _LIBCPP_INLINE_VISIBILITY
1180    basic_ifstream& operator=(basic_ifstream&& __rhs);
1181    _LIBCPP_INLINE_VISIBILITY
1182    void swap(basic_ifstream& __rhs);
1183
1184    _LIBCPP_INLINE_VISIBILITY
1185    basic_filebuf<char_type, traits_type>* rdbuf() const;
1186    _LIBCPP_INLINE_VISIBILITY
1187    bool is_open() const;
1188    void open(const char* __s, ios_base::openmode __mode = ios_base::in);
1189#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1190    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
1191#endif
1192    void open(const string& __s, ios_base::openmode __mode = ios_base::in);
1193#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
1194    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
1195    void open(const filesystem::path& __p,
1196              ios_base::openmode __mode = ios_base::in) {
1197      return open(__p.c_str(), __mode);
1198    }
1199#endif // _LIBCPP_STD_VER >= 17
1200
1201    _LIBCPP_INLINE_VISIBILITY
1202    void __open(int __fd, ios_base::openmode __mode);
1203    _LIBCPP_INLINE_VISIBILITY
1204    void close();
1205
1206private:
1207    basic_filebuf<char_type, traits_type> __sb_;
1208};
1209
1210template <class _CharT, class _Traits>
1211inline
1212basic_ifstream<_CharT, _Traits>::basic_ifstream()
1213    : basic_istream<char_type, traits_type>(&__sb_)
1214{
1215}
1216
1217template <class _CharT, class _Traits>
1218inline
1219basic_ifstream<_CharT, _Traits>::basic_ifstream(const char* __s, ios_base::openmode __mode)
1220    : basic_istream<char_type, traits_type>(&__sb_)
1221{
1222    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1223        this->setstate(ios_base::failbit);
1224}
1225
1226#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1227template <class _CharT, class _Traits>
1228inline
1229basic_ifstream<_CharT, _Traits>::basic_ifstream(const wchar_t* __s, ios_base::openmode __mode)
1230    : basic_istream<char_type, traits_type>(&__sb_)
1231{
1232    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1233        this->setstate(ios_base::failbit);
1234}
1235#endif
1236
1237template <class _CharT, class _Traits>
1238inline
1239basic_ifstream<_CharT, _Traits>::basic_ifstream(const string& __s, ios_base::openmode __mode)
1240    : basic_istream<char_type, traits_type>(&__sb_)
1241{
1242    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
1243        this->setstate(ios_base::failbit);
1244}
1245
1246template <class _CharT, class _Traits>
1247inline
1248basic_ifstream<_CharT, _Traits>::basic_ifstream(basic_ifstream&& __rhs)
1249    : basic_istream<char_type, traits_type>(_VSTD::move(__rhs)),
1250      __sb_(_VSTD::move(__rhs.__sb_))
1251{
1252    this->set_rdbuf(&__sb_);
1253}
1254
1255template <class _CharT, class _Traits>
1256inline
1257basic_ifstream<_CharT, _Traits>&
1258basic_ifstream<_CharT, _Traits>::operator=(basic_ifstream&& __rhs)
1259{
1260    basic_istream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
1261    __sb_ = _VSTD::move(__rhs.__sb_);
1262    return *this;
1263}
1264
1265template <class _CharT, class _Traits>
1266inline
1267void
1268basic_ifstream<_CharT, _Traits>::swap(basic_ifstream& __rhs)
1269{
1270    basic_istream<char_type, traits_type>::swap(__rhs);
1271    __sb_.swap(__rhs.__sb_);
1272}
1273
1274template <class _CharT, class _Traits>
1275inline _LIBCPP_INLINE_VISIBILITY
1276void
1277swap(basic_ifstream<_CharT, _Traits>& __x, basic_ifstream<_CharT, _Traits>& __y)
1278{
1279    __x.swap(__y);
1280}
1281
1282template <class _CharT, class _Traits>
1283inline
1284basic_filebuf<_CharT, _Traits>*
1285basic_ifstream<_CharT, _Traits>::rdbuf() const
1286{
1287    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1288}
1289
1290template <class _CharT, class _Traits>
1291inline
1292bool
1293basic_ifstream<_CharT, _Traits>::is_open() const
1294{
1295    return __sb_.is_open();
1296}
1297
1298template <class _CharT, class _Traits>
1299void
1300basic_ifstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
1301{
1302    if (__sb_.open(__s, __mode | ios_base::in))
1303        this->clear();
1304    else
1305        this->setstate(ios_base::failbit);
1306}
1307
1308#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1309template <class _CharT, class _Traits>
1310void
1311basic_ifstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
1312{
1313    if (__sb_.open(__s, __mode | ios_base::in))
1314        this->clear();
1315    else
1316        this->setstate(ios_base::failbit);
1317}
1318#endif
1319
1320template <class _CharT, class _Traits>
1321void
1322basic_ifstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
1323{
1324    if (__sb_.open(__s, __mode | ios_base::in))
1325        this->clear();
1326    else
1327        this->setstate(ios_base::failbit);
1328}
1329
1330template <class _CharT, class _Traits>
1331inline
1332void basic_ifstream<_CharT, _Traits>::__open(int __fd,
1333                                             ios_base::openmode __mode) {
1334  if (__sb_.__open(__fd, __mode | ios_base::in))
1335    this->clear();
1336  else
1337    this->setstate(ios_base::failbit);
1338}
1339
1340template <class _CharT, class _Traits>
1341inline
1342void
1343basic_ifstream<_CharT, _Traits>::close()
1344{
1345    if (__sb_.close() == 0)
1346        this->setstate(ios_base::failbit);
1347}
1348
1349// basic_ofstream
1350
1351template <class _CharT, class _Traits>
1352class _LIBCPP_TEMPLATE_VIS basic_ofstream
1353    : public basic_ostream<_CharT, _Traits>
1354{
1355public:
1356    typedef _CharT                         char_type;
1357    typedef _Traits                        traits_type;
1358    typedef typename traits_type::int_type int_type;
1359    typedef typename traits_type::pos_type pos_type;
1360    typedef typename traits_type::off_type off_type;
1361
1362    _LIBCPP_INLINE_VISIBILITY
1363    basic_ofstream();
1364    _LIBCPP_INLINE_VISIBILITY
1365    explicit basic_ofstream(const char* __s, ios_base::openmode __mode = ios_base::out);
1366#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1367    _LIBCPP_INLINE_VISIBILITY
1368    explicit basic_ofstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
1369#endif
1370    _LIBCPP_INLINE_VISIBILITY
1371    explicit basic_ofstream(const string& __s, ios_base::openmode __mode = ios_base::out);
1372
1373#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
1374    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
1375    explicit basic_ofstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::out)
1376      : basic_ofstream(__p.c_str(), __mode) {}
1377#endif // _LIBCPP_STD_VER >= 17
1378
1379    _LIBCPP_INLINE_VISIBILITY
1380    basic_ofstream(basic_ofstream&& __rhs);
1381    _LIBCPP_INLINE_VISIBILITY
1382    basic_ofstream& operator=(basic_ofstream&& __rhs);
1383    _LIBCPP_INLINE_VISIBILITY
1384    void swap(basic_ofstream& __rhs);
1385
1386    _LIBCPP_INLINE_VISIBILITY
1387    basic_filebuf<char_type, traits_type>* rdbuf() const;
1388    _LIBCPP_INLINE_VISIBILITY
1389    bool is_open() const;
1390    void open(const char* __s, ios_base::openmode __mode = ios_base::out);
1391#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1392    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
1393#endif
1394    void open(const string& __s, ios_base::openmode __mode = ios_base::out);
1395
1396#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
1397    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
1398    void open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::out)
1399    { return open(__p.c_str(), __mode); }
1400#endif // _LIBCPP_STD_VER >= 17
1401
1402    _LIBCPP_INLINE_VISIBILITY
1403    void __open(int __fd, ios_base::openmode __mode);
1404    _LIBCPP_INLINE_VISIBILITY
1405    void close();
1406
1407private:
1408    basic_filebuf<char_type, traits_type> __sb_;
1409};
1410
1411template <class _CharT, class _Traits>
1412inline
1413basic_ofstream<_CharT, _Traits>::basic_ofstream()
1414    : basic_ostream<char_type, traits_type>(&__sb_)
1415{
1416}
1417
1418template <class _CharT, class _Traits>
1419inline
1420basic_ofstream<_CharT, _Traits>::basic_ofstream(const char* __s, ios_base::openmode __mode)
1421    : basic_ostream<char_type, traits_type>(&__sb_)
1422{
1423    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1424        this->setstate(ios_base::failbit);
1425}
1426
1427#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1428template <class _CharT, class _Traits>
1429inline
1430basic_ofstream<_CharT, _Traits>::basic_ofstream(const wchar_t* __s, ios_base::openmode __mode)
1431    : basic_ostream<char_type, traits_type>(&__sb_)
1432{
1433    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1434        this->setstate(ios_base::failbit);
1435}
1436#endif
1437
1438template <class _CharT, class _Traits>
1439inline
1440basic_ofstream<_CharT, _Traits>::basic_ofstream(const string& __s, ios_base::openmode __mode)
1441    : basic_ostream<char_type, traits_type>(&__sb_)
1442{
1443    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
1444        this->setstate(ios_base::failbit);
1445}
1446
1447template <class _CharT, class _Traits>
1448inline
1449basic_ofstream<_CharT, _Traits>::basic_ofstream(basic_ofstream&& __rhs)
1450    : basic_ostream<char_type, traits_type>(_VSTD::move(__rhs)),
1451      __sb_(_VSTD::move(__rhs.__sb_))
1452{
1453    this->set_rdbuf(&__sb_);
1454}
1455
1456template <class _CharT, class _Traits>
1457inline
1458basic_ofstream<_CharT, _Traits>&
1459basic_ofstream<_CharT, _Traits>::operator=(basic_ofstream&& __rhs)
1460{
1461    basic_ostream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
1462    __sb_ = _VSTD::move(__rhs.__sb_);
1463    return *this;
1464}
1465
1466template <class _CharT, class _Traits>
1467inline
1468void
1469basic_ofstream<_CharT, _Traits>::swap(basic_ofstream& __rhs)
1470{
1471    basic_ostream<char_type, traits_type>::swap(__rhs);
1472    __sb_.swap(__rhs.__sb_);
1473}
1474
1475template <class _CharT, class _Traits>
1476inline _LIBCPP_INLINE_VISIBILITY
1477void
1478swap(basic_ofstream<_CharT, _Traits>& __x, basic_ofstream<_CharT, _Traits>& __y)
1479{
1480    __x.swap(__y);
1481}
1482
1483template <class _CharT, class _Traits>
1484inline
1485basic_filebuf<_CharT, _Traits>*
1486basic_ofstream<_CharT, _Traits>::rdbuf() const
1487{
1488    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1489}
1490
1491template <class _CharT, class _Traits>
1492inline
1493bool
1494basic_ofstream<_CharT, _Traits>::is_open() const
1495{
1496    return __sb_.is_open();
1497}
1498
1499template <class _CharT, class _Traits>
1500void
1501basic_ofstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
1502{
1503    if (__sb_.open(__s, __mode | ios_base::out))
1504        this->clear();
1505    else
1506        this->setstate(ios_base::failbit);
1507}
1508
1509#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1510template <class _CharT, class _Traits>
1511void
1512basic_ofstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
1513{
1514    if (__sb_.open(__s, __mode | ios_base::out))
1515        this->clear();
1516    else
1517        this->setstate(ios_base::failbit);
1518}
1519#endif
1520
1521template <class _CharT, class _Traits>
1522void
1523basic_ofstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
1524{
1525    if (__sb_.open(__s, __mode | ios_base::out))
1526        this->clear();
1527    else
1528        this->setstate(ios_base::failbit);
1529}
1530
1531template <class _CharT, class _Traits>
1532inline
1533void basic_ofstream<_CharT, _Traits>::__open(int __fd,
1534                                             ios_base::openmode __mode) {
1535  if (__sb_.__open(__fd, __mode | ios_base::out))
1536    this->clear();
1537  else
1538    this->setstate(ios_base::failbit);
1539}
1540
1541template <class _CharT, class _Traits>
1542inline
1543void
1544basic_ofstream<_CharT, _Traits>::close()
1545{
1546    if (__sb_.close() == nullptr)
1547        this->setstate(ios_base::failbit);
1548}
1549
1550// basic_fstream
1551
1552template <class _CharT, class _Traits>
1553class _LIBCPP_TEMPLATE_VIS basic_fstream
1554    : public basic_iostream<_CharT, _Traits>
1555{
1556public:
1557    typedef _CharT                         char_type;
1558    typedef _Traits                        traits_type;
1559    typedef typename traits_type::int_type int_type;
1560    typedef typename traits_type::pos_type pos_type;
1561    typedef typename traits_type::off_type off_type;
1562
1563    _LIBCPP_INLINE_VISIBILITY
1564    basic_fstream();
1565    _LIBCPP_INLINE_VISIBILITY
1566    explicit basic_fstream(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1567#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1568    _LIBCPP_INLINE_VISIBILITY
1569    explicit basic_fstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1570#endif
1571    _LIBCPP_INLINE_VISIBILITY
1572    explicit basic_fstream(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1573
1574#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
1575    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
1576    explicit basic_fstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in | ios_base::out)
1577      : basic_fstream(__p.c_str(), __mode) {}
1578#endif // _LIBCPP_STD_VER >= 17
1579
1580    _LIBCPP_INLINE_VISIBILITY
1581    basic_fstream(basic_fstream&& __rhs);
1582
1583    _LIBCPP_INLINE_VISIBILITY
1584    basic_fstream& operator=(basic_fstream&& __rhs);
1585
1586    _LIBCPP_INLINE_VISIBILITY
1587    void swap(basic_fstream& __rhs);
1588
1589    _LIBCPP_INLINE_VISIBILITY
1590    basic_filebuf<char_type, traits_type>* rdbuf() const;
1591    _LIBCPP_INLINE_VISIBILITY
1592    bool is_open() const;
1593    void open(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1594#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1595    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1596#endif
1597    void open(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
1598
1599#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
1600    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
1601    void open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in|ios_base::out)
1602    { return open(__p.c_str(), __mode); }
1603#endif // _LIBCPP_STD_VER >= 17
1604
1605    _LIBCPP_INLINE_VISIBILITY
1606    void close();
1607
1608private:
1609    basic_filebuf<char_type, traits_type> __sb_;
1610};
1611
1612template <class _CharT, class _Traits>
1613inline
1614basic_fstream<_CharT, _Traits>::basic_fstream()
1615    : basic_iostream<char_type, traits_type>(&__sb_)
1616{
1617}
1618
1619template <class _CharT, class _Traits>
1620inline
1621basic_fstream<_CharT, _Traits>::basic_fstream(const char* __s, ios_base::openmode __mode)
1622    : basic_iostream<char_type, traits_type>(&__sb_)
1623{
1624    if (__sb_.open(__s, __mode) == nullptr)
1625        this->setstate(ios_base::failbit);
1626}
1627
1628#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1629template <class _CharT, class _Traits>
1630inline
1631basic_fstream<_CharT, _Traits>::basic_fstream(const wchar_t* __s, ios_base::openmode __mode)
1632    : basic_iostream<char_type, traits_type>(&__sb_)
1633{
1634    if (__sb_.open(__s, __mode) == nullptr)
1635        this->setstate(ios_base::failbit);
1636}
1637#endif
1638
1639template <class _CharT, class _Traits>
1640inline
1641basic_fstream<_CharT, _Traits>::basic_fstream(const string& __s, ios_base::openmode __mode)
1642    : basic_iostream<char_type, traits_type>(&__sb_)
1643{
1644    if (__sb_.open(__s, __mode) == nullptr)
1645        this->setstate(ios_base::failbit);
1646}
1647
1648template <class _CharT, class _Traits>
1649inline
1650basic_fstream<_CharT, _Traits>::basic_fstream(basic_fstream&& __rhs)
1651    : basic_iostream<char_type, traits_type>(_VSTD::move(__rhs)),
1652      __sb_(_VSTD::move(__rhs.__sb_))
1653{
1654    this->set_rdbuf(&__sb_);
1655}
1656
1657template <class _CharT, class _Traits>
1658inline
1659basic_fstream<_CharT, _Traits>&
1660basic_fstream<_CharT, _Traits>::operator=(basic_fstream&& __rhs)
1661{
1662    basic_iostream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
1663    __sb_ = _VSTD::move(__rhs.__sb_);
1664    return *this;
1665}
1666
1667template <class _CharT, class _Traits>
1668inline
1669void
1670basic_fstream<_CharT, _Traits>::swap(basic_fstream& __rhs)
1671{
1672    basic_iostream<char_type, traits_type>::swap(__rhs);
1673    __sb_.swap(__rhs.__sb_);
1674}
1675
1676template <class _CharT, class _Traits>
1677inline _LIBCPP_INLINE_VISIBILITY
1678void
1679swap(basic_fstream<_CharT, _Traits>& __x, basic_fstream<_CharT, _Traits>& __y)
1680{
1681    __x.swap(__y);
1682}
1683
1684template <class _CharT, class _Traits>
1685inline
1686basic_filebuf<_CharT, _Traits>*
1687basic_fstream<_CharT, _Traits>::rdbuf() const
1688{
1689    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
1690}
1691
1692template <class _CharT, class _Traits>
1693inline
1694bool
1695basic_fstream<_CharT, _Traits>::is_open() const
1696{
1697    return __sb_.is_open();
1698}
1699
1700template <class _CharT, class _Traits>
1701void
1702basic_fstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
1703{
1704    if (__sb_.open(__s, __mode))
1705        this->clear();
1706    else
1707        this->setstate(ios_base::failbit);
1708}
1709
1710#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
1711template <class _CharT, class _Traits>
1712void
1713basic_fstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
1714{
1715    if (__sb_.open(__s, __mode))
1716        this->clear();
1717    else
1718        this->setstate(ios_base::failbit);
1719}
1720#endif
1721
1722template <class _CharT, class _Traits>
1723void
1724basic_fstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
1725{
1726    if (__sb_.open(__s, __mode))
1727        this->clear();
1728    else
1729        this->setstate(ios_base::failbit);
1730}
1731
1732template <class _CharT, class _Traits>
1733inline
1734void
1735basic_fstream<_CharT, _Traits>::close()
1736{
1737    if (__sb_.close() == nullptr)
1738        this->setstate(ios_base::failbit);
1739}
1740
1741#if defined(_LIBCPP_ABI_ENABLE_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1)
1742extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ifstream<char>;
1743extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ofstream<char>;
1744extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_filebuf<char>;
1745#endif
1746
1747_LIBCPP_END_NAMESPACE_STD
1748
1749#endif // _LIBCPP_HAS_NO_FSTREAM
1750
1751_LIBCPP_POP_MACROS
1752
1753#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1754#  include <atomic>
1755#  include <concepts>
1756#  include <iosfwd>
1757#  include <limits>
1758#  include <new>
1759#  include <stdexcept>
1760#  include <type_traits>
1761#endif
1762
1763#endif // _LIBCPP_FSTREAM
1764