xref: /netbsd-src/external/gpl3/gcc.old/dist/libstdc++-v3/include/bits/fs_path.h (revision 53d1339bf7f9c7367b35a9e1ebe693f9b047a47b)
1 // Class filesystem::path -*- C++ -*-
2 
3 // Copyright (C) 2014-2019 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file include/bits/fs_path.h
26  *  This is an internal header file, included by other library headers.
27  *  Do not attempt to use it directly. @headername{filesystem}
28  */
29 
30 #ifndef _GLIBCXX_FS_PATH_H
31 #define _GLIBCXX_FS_PATH_H 1
32 
33 #if __cplusplus >= 201703L
34 
35 #include <utility>
36 #include <type_traits>
37 #include <locale>
38 #include <iosfwd>
39 #include <iomanip>
40 #include <codecvt>
41 #include <string_view>
42 #include <system_error>
43 #include <bits/stl_algobase.h>
44 #include <bits/locale_conv.h>
45 #include <ext/concurrence.h>
46 #include <bits/shared_ptr.h>
47 #include <bits/unique_ptr.h>
48 
49 #if defined(_WIN32) && !defined(__CYGWIN__)
50 # define _GLIBCXX_FILESYSTEM_IS_WINDOWS 1
51 # include <algorithm>
52 #endif
53 
54 namespace std _GLIBCXX_VISIBILITY(default)
55 {
56 _GLIBCXX_BEGIN_NAMESPACE_VERSION
57 
58 namespace filesystem
59 {
60 _GLIBCXX_BEGIN_NAMESPACE_CXX11
61 
62   /**
63    * @ingroup filesystem
64    * @{
65    */
66 
67   /// A filesystem path.
68   class path
69   {
70     template<typename _CharT, typename _Ch = remove_const_t<_CharT>>
71       using __is_encoded_char
72 	= __or_<is_same<_Ch, char>,
73 #ifdef _GLIBCXX_USE_CHAR8_T
74 		is_same<_Ch, char8_t>,
75 #endif
76 		is_same<_Ch, wchar_t>,
77 		is_same<_Ch, char16_t>,
78 		is_same<_Ch, char32_t>>;
79 
80     template<typename _Iter,
81 	     typename _Iter_traits = std::iterator_traits<_Iter>>
82       using __is_path_iter_src
83 	= __and_<__is_encoded_char<typename _Iter_traits::value_type>,
84 		 std::is_base_of<std::input_iterator_tag,
85 				 typename _Iter_traits::iterator_category>>;
86 
87     template<typename _Iter>
88       static __is_path_iter_src<_Iter>
89       __is_path_src(_Iter, int);
90 
91     template<typename _CharT, typename _Traits, typename _Alloc>
92       static __is_encoded_char<_CharT>
93       __is_path_src(const basic_string<_CharT, _Traits, _Alloc>&, int);
94 
95     template<typename _CharT, typename _Traits>
96       static __is_encoded_char<_CharT>
97       __is_path_src(const basic_string_view<_CharT, _Traits>&, int);
98 
99     template<typename _Unknown>
100       static std::false_type
101       __is_path_src(const _Unknown&, ...);
102 
103     template<typename _Tp1, typename _Tp2>
104       struct __constructible_from;
105 
106     template<typename _Iter>
107       struct __constructible_from<_Iter, _Iter>
108       : __is_path_iter_src<_Iter>
109       { };
110 
111     template<typename _Source>
112       struct __constructible_from<_Source, void>
113       : decltype(__is_path_src(std::declval<_Source>(), 0))
114       { };
115 
116     template<typename _Tp1, typename _Tp2 = void>
117       using _Path = typename
118 	std::enable_if<__and_<__not_<is_same<remove_cv_t<_Tp1>, path>>,
119 			      __not_<is_void<remove_pointer_t<_Tp1>>>,
120 			      __constructible_from<_Tp1, _Tp2>>::value,
121 		       path>::type;
122 
123     template<typename _Source>
124       static _Source
125       _S_range_begin(_Source __begin) { return __begin; }
126 
127     struct __null_terminated { };
128 
129     template<typename _Source>
130       static __null_terminated
131       _S_range_end(_Source) { return {}; }
132 
133     template<typename _CharT, typename _Traits, typename _Alloc>
134       static const _CharT*
135       _S_range_begin(const basic_string<_CharT, _Traits, _Alloc>& __str)
136       { return __str.data(); }
137 
138     template<typename _CharT, typename _Traits, typename _Alloc>
139       static const _CharT*
140       _S_range_end(const basic_string<_CharT, _Traits, _Alloc>& __str)
141       { return __str.data() + __str.size(); }
142 
143     template<typename _CharT, typename _Traits>
144       static const _CharT*
145       _S_range_begin(const basic_string_view<_CharT, _Traits>& __str)
146       { return __str.data(); }
147 
148     template<typename _CharT, typename _Traits>
149       static const _CharT*
150       _S_range_end(const basic_string_view<_CharT, _Traits>& __str)
151       { return __str.data() + __str.size(); }
152 
153     template<typename _Tp,
154 	     typename _Iter = decltype(_S_range_begin(std::declval<_Tp>())),
155 	     typename _Val = typename std::iterator_traits<_Iter>::value_type>
156       using __value_type_is_char
157 	= std::enable_if_t<std::is_same_v<std::remove_const_t<_Val>, char>>;
158 
159   public:
160 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
161     typedef wchar_t				value_type;
162     static constexpr value_type			preferred_separator = L'\\';
163 #else
164     typedef char				value_type;
165     static constexpr value_type			preferred_separator = '/';
166 #endif
167     typedef std::basic_string<value_type>	string_type;
168 
169     enum format : unsigned char { native_format, generic_format, auto_format };
170 
171     // constructors and destructor
172 
173     path() noexcept { }
174 
175     path(const path& __p) = default;
176 
177     path(path&& __p)
178 #if _GLIBCXX_USE_CXX11_ABI || _GLIBCXX_FULLY_DYNAMIC_STRING == 0
179       noexcept
180 #endif
181     : _M_pathname(std::move(__p._M_pathname)),
182       _M_cmpts(std::move(__p._M_cmpts))
183     { __p.clear(); }
184 
185     path(string_type&& __source, format = auto_format)
186     : _M_pathname(std::move(__source))
187     { _M_split_cmpts(); }
188 
189     template<typename _Source,
190 	     typename _Require = _Path<_Source>>
191       path(_Source const& __source, format = auto_format)
192       : _M_pathname(_S_convert(_S_range_begin(__source),
193 			       _S_range_end(__source)))
194       { _M_split_cmpts(); }
195 
196     template<typename _InputIterator,
197 	     typename _Require = _Path<_InputIterator, _InputIterator>>
198       path(_InputIterator __first, _InputIterator __last, format = auto_format)
199       : _M_pathname(_S_convert(__first, __last))
200       { _M_split_cmpts(); }
201 
202     template<typename _Source,
203 	     typename _Require = _Path<_Source>,
204 	     typename _Require2 = __value_type_is_char<_Source>>
205       path(_Source const& __source, const locale& __loc, format = auto_format)
206       : _M_pathname(_S_convert_loc(_S_range_begin(__source),
207 				   _S_range_end(__source), __loc))
208       { _M_split_cmpts(); }
209 
210     template<typename _InputIterator,
211 	     typename _Require = _Path<_InputIterator, _InputIterator>,
212 	     typename _Require2 = __value_type_is_char<_InputIterator>>
213       path(_InputIterator __first, _InputIterator __last, const locale& __loc,
214 	   format = auto_format)
215       : _M_pathname(_S_convert_loc(__first, __last, __loc))
216       { _M_split_cmpts(); }
217 
218     ~path() = default;
219 
220     // assignments
221 
222     path& operator=(const path&);
223     path& operator=(path&&) noexcept;
224     path& operator=(string_type&& __source);
225     path& assign(string_type&& __source);
226 
227     template<typename _Source>
228       _Path<_Source>&
229       operator=(_Source const& __source)
230       { return *this = path(__source); }
231 
232     template<typename _Source>
233       _Path<_Source>&
234       assign(_Source const& __source)
235       { return *this = path(__source); }
236 
237     template<typename _InputIterator>
238       _Path<_InputIterator, _InputIterator>&
239       assign(_InputIterator __first, _InputIterator __last)
240       { return *this = path(__first, __last); }
241 
242     // appends
243 
244     path& operator/=(const path& __p);
245 
246     template <class _Source>
247       _Path<_Source>&
248       operator/=(_Source const& __source)
249       {
250 	_M_append(_S_convert(_S_range_begin(__source), _S_range_end(__source)));
251 	return *this;
252       }
253 
254     template<typename _Source>
255       _Path<_Source>&
256       append(_Source const& __source)
257       {
258 	_M_append(_S_convert(_S_range_begin(__source), _S_range_end(__source)));
259 	return *this;
260       }
261 
262     template<typename _InputIterator>
263       _Path<_InputIterator, _InputIterator>&
264       append(_InputIterator __first, _InputIterator __last)
265       {
266 	_M_append(_S_convert(__first, __last));
267 	return *this;
268       }
269 
270     // concatenation
271 
272     path& operator+=(const path& __x);
273     path& operator+=(const string_type& __x);
274     path& operator+=(const value_type* __x);
275     path& operator+=(value_type __x);
276     path& operator+=(basic_string_view<value_type> __x);
277 
278     template<typename _Source>
279       _Path<_Source>&
280       operator+=(_Source const& __x) { return concat(__x); }
281 
282     template<typename _CharT>
283       _Path<_CharT*, _CharT*>&
284       operator+=(_CharT __x);
285 
286     template<typename _Source>
287       _Path<_Source>&
288       concat(_Source const& __x)
289       {
290 	_M_concat(_S_convert(_S_range_begin(__x), _S_range_end(__x)));
291 	return *this;
292       }
293 
294     template<typename _InputIterator>
295       _Path<_InputIterator, _InputIterator>&
296       concat(_InputIterator __first, _InputIterator __last)
297       {
298 	_M_concat(_S_convert(__first, __last));
299 	return *this;
300       }
301 
302     // modifiers
303 
304     void clear() noexcept { _M_pathname.clear(); _M_split_cmpts(); }
305 
306     path& make_preferred();
307     path& remove_filename();
308     path& replace_filename(const path& __replacement);
309     path& replace_extension(const path& __replacement = path());
310 
311     void swap(path& __rhs) noexcept;
312 
313     // native format observers
314 
315     const string_type&  native() const noexcept { return _M_pathname; }
316     const value_type*   c_str() const noexcept { return _M_pathname.c_str(); }
317     operator string_type() const { return _M_pathname; }
318 
319     template<typename _CharT, typename _Traits = std::char_traits<_CharT>,
320 	     typename _Allocator = std::allocator<_CharT>>
321       std::basic_string<_CharT, _Traits, _Allocator>
322       string(const _Allocator& __a = _Allocator()) const;
323 
324     std::string    string() const;
325 #if _GLIBCXX_USE_WCHAR_T
326     std::wstring   wstring() const;
327 #endif
328 #ifdef _GLIBCXX_USE_CHAR8_T
329     __attribute__((__abi_tag__("__u8")))
330     std::u8string  u8string() const;
331 #else
332     std::string    u8string() const;
333 #endif // _GLIBCXX_USE_CHAR8_T
334     std::u16string u16string() const;
335     std::u32string u32string() const;
336 
337     // generic format observers
338     template<typename _CharT, typename _Traits = std::char_traits<_CharT>,
339 	     typename _Allocator = std::allocator<_CharT>>
340       std::basic_string<_CharT, _Traits, _Allocator>
341       generic_string(const _Allocator& __a = _Allocator()) const;
342 
343     std::string    generic_string() const;
344 #if _GLIBCXX_USE_WCHAR_T
345     std::wstring   generic_wstring() const;
346 #endif
347 #ifdef _GLIBCXX_USE_CHAR8_T
348     __attribute__((__abi_tag__("__u8")))
349     std::u8string  generic_u8string() const;
350 #else
351     std::string    generic_u8string() const;
352 #endif // _GLIBCXX_USE_CHAR8_T
353     std::u16string generic_u16string() const;
354     std::u32string generic_u32string() const;
355 
356     // compare
357 
358     int compare(const path& __p) const noexcept;
359     int compare(const string_type& __s) const noexcept;
360     int compare(const value_type* __s) const noexcept;
361     int compare(basic_string_view<value_type> __s) const noexcept;
362 
363     // decomposition
364 
365     path root_name() const;
366     path root_directory() const;
367     path root_path() const;
368     path relative_path() const;
369     path parent_path() const;
370     path filename() const;
371     path stem() const;
372     path extension() const;
373 
374     // query
375 
376     [[nodiscard]] bool empty() const noexcept { return _M_pathname.empty(); }
377     bool has_root_name() const noexcept;
378     bool has_root_directory() const noexcept;
379     bool has_root_path() const noexcept;
380     bool has_relative_path() const noexcept;
381     bool has_parent_path() const noexcept;
382     bool has_filename() const noexcept;
383     bool has_stem() const noexcept;
384     bool has_extension() const noexcept;
385     bool is_absolute() const noexcept;
386     bool is_relative() const noexcept { return !is_absolute(); }
387 
388     // generation
389     path lexically_normal() const;
390     path lexically_relative(const path& base) const;
391     path lexically_proximate(const path& base) const;
392 
393     // iterators
394     class iterator;
395     typedef iterator const_iterator;
396 
397     iterator begin() const;
398     iterator end() const;
399 
400     /// Write a path to a stream
401     template<typename _CharT, typename _Traits>
402       friend std::basic_ostream<_CharT, _Traits>&
403       operator<<(std::basic_ostream<_CharT, _Traits>& __os, const path& __p)
404       {
405 	__os << std::quoted(__p.string<_CharT, _Traits>());
406 	return __os;
407       }
408 
409     /// Read a path from a stream
410     template<typename _CharT, typename _Traits>
411       friend std::basic_istream<_CharT, _Traits>&
412       operator>>(std::basic_istream<_CharT, _Traits>& __is, path& __p)
413       {
414 	std::basic_string<_CharT, _Traits> __tmp;
415 	if (__is >> std::quoted(__tmp))
416 	  __p = std::move(__tmp);
417 	return __is;
418       }
419 
420     // non-member operators
421 
422     /// Compare paths
423     friend bool operator<(const path& __lhs, const path& __rhs) noexcept
424     { return __lhs.compare(__rhs) < 0; }
425 
426     /// Compare paths
427     friend bool operator<=(const path& __lhs, const path& __rhs) noexcept
428     { return !(__rhs < __lhs); }
429 
430     /// Compare paths
431     friend bool operator>(const path& __lhs, const path& __rhs) noexcept
432     { return __rhs < __lhs; }
433 
434     /// Compare paths
435     friend bool operator>=(const path& __lhs, const path& __rhs) noexcept
436     { return !(__lhs < __rhs); }
437 
438     /// Compare paths
439     friend bool operator==(const path& __lhs, const path& __rhs) noexcept
440     { return __lhs.compare(__rhs) == 0; }
441 
442     /// Compare paths
443     friend bool operator!=(const path& __lhs, const path& __rhs) noexcept
444     { return !(__lhs == __rhs); }
445 
446     /// Append one path to another
447     friend path operator/(const path& __lhs, const path& __rhs)
448     {
449       path __result(__lhs);
450       __result /= __rhs;
451       return __result;
452     }
453 
454     // Create a basic_string by reading until a null character.
455     template<typename _InputIterator,
456 	     typename _Traits = std::iterator_traits<_InputIterator>,
457 	     typename _CharT
458 	       = typename std::remove_cv_t<typename _Traits::value_type>>
459       static std::basic_string<_CharT>
460       _S_string_from_iter(_InputIterator __source)
461       {
462 	std::basic_string<_CharT> __str;
463 	for (_CharT __ch = *__source; __ch != _CharT(); __ch = *++__source)
464 	  __str.push_back(__ch);
465 	return __str;
466       }
467 
468   private:
469     enum class _Type : unsigned char {
470       _Multi = 0, _Root_name, _Root_dir, _Filename
471     };
472 
473     path(basic_string_view<value_type> __str, _Type __type)
474     : _M_pathname(__str)
475     {
476       __glibcxx_assert(__type != _Type::_Multi);
477       _M_cmpts.type(__type);
478     }
479 
480     enum class _Split { _Stem, _Extension };
481 
482     void _M_append(basic_string_view<value_type>);
483     void _M_concat(basic_string_view<value_type>);
484 
485     pair<const string_type*, size_t> _M_find_extension() const noexcept;
486 
487     template<typename _CharT>
488       struct _Cvt;
489 
490     static basic_string_view<value_type>
491     _S_convert(value_type* __src, __null_terminated)
492     { return __src; }
493 
494     static basic_string_view<value_type>
495     _S_convert(const value_type* __src, __null_terminated)
496     { return __src; }
497 
498     static basic_string_view<value_type>
499     _S_convert(value_type* __first, value_type* __last)
500     { return {__first, __last - __first}; }
501 
502     static basic_string_view<value_type>
503     _S_convert(const value_type* __first, const value_type* __last)
504     { return {__first, __last - __first}; }
505 
506     template<typename _Iter>
507       static string_type
508       _S_convert(_Iter __first, _Iter __last)
509       {
510 	using __value_type = typename std::iterator_traits<_Iter>::value_type;
511 	return _Cvt<typename remove_cv<__value_type>::type>::
512 	  _S_convert(__first, __last);
513       }
514 
515     template<typename _InputIterator>
516       static string_type
517       _S_convert(_InputIterator __src, __null_terminated)
518       {
519 	// Read from iterator into basic_string until a null value is seen:
520 	auto __s = _S_string_from_iter(__src);
521 	// Convert (if needed) from iterator's value type to path::value_type:
522 	return string_type(_S_convert(__s.data(), __s.data() + __s.size()));
523       }
524 
525     static string_type
526     _S_convert_loc(const char* __first, const char* __last,
527 		   const std::locale& __loc);
528 
529     template<typename _Iter>
530       static string_type
531       _S_convert_loc(_Iter __first, _Iter __last, const std::locale& __loc)
532       {
533 	const std::string __str(__first, __last);
534 	return _S_convert_loc(__str.data(), __str.data()+__str.size(), __loc);
535       }
536 
537     template<typename _InputIterator>
538       static string_type
539       _S_convert_loc(_InputIterator __src, __null_terminated,
540 		     const std::locale& __loc)
541       {
542 	const std::string __s = _S_string_from_iter(__src);
543 	return _S_convert_loc(__s.data(), __s.data() + __s.size(), __loc);
544       }
545 
546     template<typename _CharT, typename _Traits, typename _Allocator>
547       static basic_string<_CharT, _Traits, _Allocator>
548       _S_str_convert(const string_type&, const _Allocator& __a);
549 
550     void _M_split_cmpts();
551 
552     _Type _M_type() const noexcept { return _M_cmpts.type(); }
553 
554     string_type _M_pathname;
555 
556     struct _Cmpt;
557 
558     struct _List
559     {
560       using value_type = _Cmpt;
561       using iterator = value_type*;
562       using const_iterator = const value_type*;
563 
564       _List();
565       _List(const _List&);
566       _List(_List&&) = default;
567       _List& operator=(const _List&);
568       _List& operator=(_List&&) = default;
569       ~_List() = default;
570 
571       _Type type() const noexcept
572       { return _Type{reinterpret_cast<uintptr_t>(_M_impl.get()) & 0x3}; }
573 
574       void type(_Type) noexcept;
575 
576       int size() const noexcept; // zero unless type() == _Type::_Multi
577       bool empty() const noexcept; // true unless type() == _Type::_Multi
578       void clear();
579       void swap(_List& __l) noexcept { _M_impl.swap(__l._M_impl); }
580       int capacity() const noexcept;
581       void reserve(int, bool); ///< @pre type() == _Type::_Multi
582 
583       // All the member functions below here have a precondition !empty()
584       // (and they should only be called from within the library).
585 
586       iterator begin();
587       iterator end();
588       const_iterator begin() const;
589       const_iterator end() const;
590 
591       value_type& front() noexcept;
592       value_type& back() noexcept;
593       const value_type& front() const noexcept;
594       const value_type& back() const noexcept;
595 
596       void pop_back();
597       void _M_erase_from(const_iterator __pos); // erases [__pos,end())
598 
599       struct _Impl;
600       struct _Impl_deleter
601       {
602 	void operator()(_Impl*) const noexcept;
603       };
604       unique_ptr<_Impl, _Impl_deleter> _M_impl;
605     };
606     _List _M_cmpts;
607 
608     struct _Parser;
609   };
610 
611   inline void swap(path& __lhs, path& __rhs) noexcept { __lhs.swap(__rhs); }
612 
613   size_t hash_value(const path& __p) noexcept;
614 
615   /// Exception type thrown by the Filesystem library
616   class filesystem_error : public std::system_error
617   {
618   public:
619     filesystem_error(const string& __what_arg, error_code __ec);
620 
621     filesystem_error(const string& __what_arg, const path& __p1,
622 		     error_code __ec);
623 
624     filesystem_error(const string& __what_arg, const path& __p1,
625 		     const path& __p2, error_code __ec);
626 
627     filesystem_error(const filesystem_error&) = default;
628     filesystem_error& operator=(const filesystem_error&) = default;
629 
630     // No move constructor or assignment operator.
631     // Copy rvalues instead, so that _M_impl is not left empty.
632 
633     ~filesystem_error();
634 
635     const path& path1() const noexcept;
636     const path& path2() const noexcept;
637     const char* what() const noexcept;
638 
639   private:
640     struct _Impl;
641     std::__shared_ptr<const _Impl> _M_impl;
642   };
643 
644   /// Create a path from a UTF-8-encoded sequence of char
645   template<typename _InputIterator>
646     inline auto
647     u8path(_InputIterator __first, _InputIterator __last)
648     -> decltype(filesystem::path(__first, __last, std::locale::classic()))
649     {
650 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
651       // XXX This assumes native wide encoding is UTF-16.
652       std::codecvt_utf8_utf16<path::value_type> __cvt;
653       path::string_type __tmp;
654       if constexpr (is_pointer_v<_InputIterator>)
655 	{
656 	  if (__str_codecvt_in_all(__first, __last, __tmp, __cvt))
657 	    return path{ __tmp };
658 	}
659       else
660 	{
661 	  const std::string __u8str{__first, __last};
662 	  const char* const __ptr = __u8str.data();
663 	  if (__str_codecvt_in_all(__ptr, __ptr + __u8str.size(), __tmp, __cvt))
664 	    return path{ __tmp };
665 	}
666       _GLIBCXX_THROW_OR_ABORT(filesystem_error(
667 	    "Cannot convert character sequence",
668 	    std::make_error_code(errc::illegal_byte_sequence)));
669 #else
670       // This assumes native normal encoding is UTF-8.
671       return path{ __first, __last };
672 #endif
673     }
674 
675   /// Create a path from a UTF-8-encoded sequence of char
676   template<typename _Source>
677     inline auto
678     u8path(const _Source& __source)
679     -> decltype(filesystem::path(__source, std::locale::classic()))
680     {
681 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
682       if constexpr (is_convertible_v<const _Source&, std::string_view>)
683 	{
684 	  const std::string_view __s = __source;
685 	  return filesystem::u8path(__s.data(), __s.data() + __s.size());
686 	}
687       else
688 	{
689 	  std::string __s = path::_S_string_from_iter(__source);
690 	  return filesystem::u8path(__s.data(), __s.data() + __s.size());
691 	}
692 #else
693       return path{ __source };
694 #endif
695     }
696 
697   struct path::_Cmpt : path
698   {
699     _Cmpt(basic_string_view<value_type> __s, _Type __t, size_t __pos)
700       : path(__s, __t), _M_pos(__pos) { }
701 
702     _Cmpt() : _M_pos(-1) { }
703 
704     size_t _M_pos;
705   };
706 
707   // specialize _Cvt for degenerate 'noconv' case
708   template<>
709     struct path::_Cvt<path::value_type>
710     {
711       template<typename _Iter>
712 	static string_type
713 	_S_convert(_Iter __first, _Iter __last)
714 	{ return string_type{__first, __last}; }
715     };
716 
717 #if !defined _GLIBCXX_FILESYSTEM_IS_WINDOWS  && defined _GLIBCXX_USE_CHAR8_T
718   // For POSIX converting from char8_t to char is also 'noconv'
719   template<>
720     struct path::_Cvt<char8_t>
721     {
722       template<typename _Iter>
723 	static string_type
724 	_S_convert(_Iter __first, _Iter __last)
725 	{ return string_type(__first, __last); }
726     };
727 #endif
728 
729   template<typename _CharT>
730     struct path::_Cvt
731     {
732       static string_type
733       _S_convert(const _CharT* __f, const _CharT* __l)
734       {
735 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
736 	std::wstring __wstr;
737 	if constexpr (is_same_v<_CharT, char>)
738 	  {
739 	    struct _UCvt : std::codecvt<wchar_t, char, std::mbstate_t>
740 	    { } __cvt;
741 	    if (__str_codecvt_in_all(__f, __l, __wstr, __cvt))
742 	      return __wstr;
743 	  }
744 #ifdef _GLIBCXX_USE_CHAR8_T
745 	else if constexpr (is_same_v<_CharT, char8_t>)
746 	  {
747 	    const char* __f2 = (const char*)__f;
748 	    const char* __l2 = (const char*)__l;
749 	    std::codecvt_utf8_utf16<wchar_t> __wcvt;
750 	    if (__str_codecvt_in_all(__f2, __l2, __wstr, __wcvt))
751 	      return __wstr;
752 	  }
753 #endif
754 	else // char16_t or char32_t
755 	  {
756 	    struct _UCvt : std::codecvt<_CharT, char, std::mbstate_t>
757 	    { } __cvt;
758 	    std::string __str;
759 	    if (__str_codecvt_out_all(__f, __l, __str, __cvt))
760 	      {
761 		const char* __f2 = __str.data();
762 		const char* __l2 = __f2 + __str.size();
763 		std::codecvt_utf8_utf16<wchar_t> __wcvt;
764 		if (__str_codecvt_in_all(__f2, __l2, __wstr, __wcvt))
765 		  return __wstr;
766 	      }
767 	  }
768 #else // ! windows
769 	struct _UCvt : std::codecvt<_CharT, char, std::mbstate_t>
770 	{ } __cvt;
771 	std::string __str;
772 	if (__str_codecvt_out_all(__f, __l, __str, __cvt))
773 	  return __str;
774 #endif
775 	_GLIBCXX_THROW_OR_ABORT(filesystem_error(
776 	      "Cannot convert character sequence",
777 	      std::make_error_code(errc::illegal_byte_sequence)));
778       }
779 
780       static string_type
781       _S_convert(_CharT* __f, _CharT* __l)
782       {
783 	return _S_convert(const_cast<const _CharT*>(__f),
784 			  const_cast<const _CharT*>(__l));
785       }
786 
787       template<typename _Iter>
788 	static string_type
789 	_S_convert(_Iter __first, _Iter __last)
790 	{
791 	  const std::basic_string<_CharT> __str(__first, __last);
792 	  return _S_convert(__str.data(), __str.data() + __str.size());
793 	}
794 
795       template<typename _Iter, typename _Cont>
796 	static string_type
797 	_S_convert(__gnu_cxx::__normal_iterator<_Iter, _Cont> __first,
798 		  __gnu_cxx::__normal_iterator<_Iter, _Cont> __last)
799 	{ return _S_convert(__first.base(), __last.base()); }
800     };
801 
802   /// An iterator for the components of a path
803   class path::iterator
804   {
805   public:
806     using difference_type	= std::ptrdiff_t;
807     using value_type		= path;
808     using reference		= const path&;
809     using pointer		= const path*;
810     using iterator_category	= std::bidirectional_iterator_tag;
811 
812     iterator() : _M_path(nullptr), _M_cur(), _M_at_end() { }
813 
814     iterator(const iterator&) = default;
815     iterator& operator=(const iterator&) = default;
816 
817     reference operator*() const;
818     pointer   operator->() const { return std::__addressof(**this); }
819 
820     iterator& operator++();
821     iterator  operator++(int) { auto __tmp = *this; ++*this; return __tmp; }
822 
823     iterator& operator--();
824     iterator  operator--(int) { auto __tmp = *this; --*this; return __tmp; }
825 
826     friend bool operator==(const iterator& __lhs, const iterator& __rhs)
827     { return __lhs._M_equals(__rhs); }
828 
829     friend bool operator!=(const iterator& __lhs, const iterator& __rhs)
830     { return !__lhs._M_equals(__rhs); }
831 
832   private:
833     friend class path;
834 
835     bool _M_is_multi() const { return _M_path->_M_type() == _Type::_Multi; }
836 
837     friend difference_type
838     __path_iter_distance(const iterator& __first, const iterator& __last)
839     {
840       __glibcxx_assert(__first._M_path != nullptr);
841       __glibcxx_assert(__first._M_path == __last._M_path);
842       if (__first._M_is_multi())
843 	return std::distance(__first._M_cur, __last._M_cur);
844       else if (__first._M_at_end == __last._M_at_end)
845 	return 0;
846       else
847 	return __first._M_at_end ? -1 : 1;
848     }
849 
850     friend void
851     __path_iter_advance(iterator& __i, difference_type __n)
852     {
853       if (__n == 1)
854 	++__i;
855       else if (__n == -1)
856 	--__i;
857       else if (__n != 0)
858 	{
859 	  __glibcxx_assert(__i._M_path != nullptr);
860 	  __glibcxx_assert(__i._M_is_multi());
861 	  // __glibcxx_assert(__i._M_path->_M_cmpts.end() - __i._M_cur >= __n);
862 	  __i._M_cur += __n;
863 	}
864     }
865 
866     iterator(const path* __path, path::_List::const_iterator __iter)
867     : _M_path(__path), _M_cur(__iter), _M_at_end()
868     { }
869 
870     iterator(const path* __path, bool __at_end)
871     : _M_path(__path), _M_cur(), _M_at_end(__at_end)
872     { }
873 
874     bool _M_equals(iterator) const;
875 
876     const path* 		_M_path;
877     path::_List::const_iterator _M_cur;
878     bool			_M_at_end;  // only used when type != _Multi
879   };
880 
881 
882   inline path&
883   path::operator=(path&& __p) noexcept
884   {
885     if (&__p == this) [[__unlikely__]]
886       return *this;
887 
888     _M_pathname = std::move(__p._M_pathname);
889     _M_cmpts = std::move(__p._M_cmpts);
890     __p.clear();
891     return *this;
892   }
893 
894   inline path&
895   path::operator=(string_type&& __source)
896   { return *this = path(std::move(__source)); }
897 
898   inline path&
899   path::assign(string_type&& __source)
900   { return *this = path(std::move(__source)); }
901 
902   inline path&
903   path::operator+=(const string_type& __x)
904   {
905     _M_concat(__x);
906     return *this;
907   }
908 
909   inline path&
910   path::operator+=(const value_type* __x)
911   {
912     _M_concat(__x);
913     return *this;
914   }
915 
916   inline path&
917   path::operator+=(value_type __x)
918   {
919     _M_concat(basic_string_view<value_type>(&__x, 1));
920     return *this;
921   }
922 
923   inline path&
924   path::operator+=(basic_string_view<value_type> __x)
925   {
926     _M_concat(__x);
927     return *this;
928   }
929 
930   template<typename _CharT>
931     inline path::_Path<_CharT*, _CharT*>&
932     path::operator+=(_CharT __x)
933     {
934       auto* __addr = std::__addressof(__x);
935       return concat(__addr, __addr + 1);
936     }
937 
938   inline path&
939   path::make_preferred()
940   {
941 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
942     std::replace(_M_pathname.begin(), _M_pathname.end(), L'/',
943 		 preferred_separator);
944 #endif
945     return *this;
946   }
947 
948   inline void path::swap(path& __rhs) noexcept
949   {
950     _M_pathname.swap(__rhs._M_pathname);
951     _M_cmpts.swap(__rhs._M_cmpts);
952   }
953 
954   template<typename _CharT, typename _Traits, typename _Allocator>
955     std::basic_string<_CharT, _Traits, _Allocator>
956     path::_S_str_convert(const string_type& __str, const _Allocator& __a)
957     {
958       static_assert(!is_same_v<_CharT, value_type>);
959 
960       using _WString = basic_string<_CharT, _Traits, _Allocator>;
961 
962       if (__str.size() == 0)
963 	return _WString(__a);
964 
965 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
966       // First convert native string from UTF-16 to to UTF-8.
967       // XXX This assumes that the execution wide-character set is UTF-16.
968       std::codecvt_utf8_utf16<value_type> __cvt;
969 
970       using _CharAlloc = __alloc_rebind<_Allocator, char>;
971       using _String = basic_string<char, char_traits<char>, _CharAlloc>;
972       _String __u8str{_CharAlloc{__a}};
973       const value_type* __wfirst = __str.data();
974       const value_type* __wlast = __wfirst + __str.size();
975       if (__str_codecvt_out_all(__wfirst, __wlast, __u8str, __cvt)) {
976       if constexpr (is_same_v<_CharT, char>)
977 	return __u8str; // XXX assumes native ordinary encoding is UTF-8.
978       else {
979 
980       const char* __first = __u8str.data();
981       const char* __last = __first + __u8str.size();
982 #else
983       const value_type* __first = __str.data();
984       const value_type* __last = __first + __str.size();
985 #endif
986 
987       // Convert UTF-8 string to requested format.
988 #ifdef _GLIBCXX_USE_CHAR8_T
989       if constexpr (is_same_v<_CharT, char8_t>)
990 	return _WString(__first, __last, __a);
991       else
992 #endif
993 	{
994 	  // Convert UTF-8 to wide string.
995 	  _WString __wstr(__a);
996 	  struct _UCvt : std::codecvt<_CharT, char, std::mbstate_t> { } __cvt;
997 	  if (__str_codecvt_in_all(__first, __last, __wstr, __cvt))
998 	    return __wstr;
999 	}
1000 
1001 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1002       } }
1003 #endif
1004       _GLIBCXX_THROW_OR_ABORT(filesystem_error(
1005 	    "Cannot convert character sequence",
1006 	    std::make_error_code(errc::illegal_byte_sequence)));
1007     }
1008 
1009   template<typename _CharT, typename _Traits, typename _Allocator>
1010     inline basic_string<_CharT, _Traits, _Allocator>
1011     path::string(const _Allocator& __a) const
1012     {
1013       if constexpr (is_same_v<_CharT, value_type>)
1014 	return { _M_pathname.c_str(), _M_pathname.length(), __a };
1015       else
1016 	return _S_str_convert<_CharT, _Traits>(_M_pathname, __a);
1017     }
1018 
1019   inline std::string
1020   path::string() const { return string<char>(); }
1021 
1022 #if _GLIBCXX_USE_WCHAR_T
1023   inline std::wstring
1024   path::wstring() const { return string<wchar_t>(); }
1025 #endif
1026 
1027 #ifdef _GLIBCXX_USE_CHAR8_T
1028   inline std::u8string
1029   path::u8string() const { return string<char8_t>(); }
1030 #else
1031   inline std::string
1032   path::u8string() const
1033   {
1034 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1035     std::string __str;
1036     // convert from native wide encoding (assumed to be UTF-16) to UTF-8
1037     std::codecvt_utf8_utf16<value_type> __cvt;
1038     const value_type* __first = _M_pathname.data();
1039     const value_type* __last = __first + _M_pathname.size();
1040     if (__str_codecvt_out_all(__first, __last, __str, __cvt))
1041       return __str;
1042     _GLIBCXX_THROW_OR_ABORT(filesystem_error(
1043 	  "Cannot convert character sequence",
1044 	  std::make_error_code(errc::illegal_byte_sequence)));
1045 #else
1046     return _M_pathname;
1047 #endif
1048   }
1049 #endif // _GLIBCXX_USE_CHAR8_T
1050 
1051   inline std::u16string
1052   path::u16string() const { return string<char16_t>(); }
1053 
1054   inline std::u32string
1055   path::u32string() const { return string<char32_t>(); }
1056 
1057   template<typename _CharT, typename _Traits, typename _Allocator>
1058     inline std::basic_string<_CharT, _Traits, _Allocator>
1059     path::generic_string(const _Allocator& __a) const
1060     {
1061 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1062       const value_type __slash = L'/';
1063 #else
1064       const value_type __slash = '/';
1065 #endif
1066       string_type __str(__a);
1067 
1068       if (_M_type() == _Type::_Root_dir)
1069 	__str.assign(1, __slash);
1070       else
1071 	{
1072 	  __str.reserve(_M_pathname.size());
1073 	  bool __add_slash = false;
1074 	  for (auto& __elem : *this)
1075 	    {
1076 	      if (__add_slash)
1077 		__str += __slash;
1078 	      __str += __elem._M_pathname;
1079 	      __add_slash = __elem._M_type() == _Type::_Filename;
1080 	    }
1081 	}
1082 
1083       if constexpr (is_same_v<_CharT, value_type>)
1084 	return __str;
1085       else
1086 	return _S_str_convert<_CharT, _Traits>(__str, __a);
1087     }
1088 
1089   inline std::string
1090   path::generic_string() const
1091   { return generic_string<char>(); }
1092 
1093 #if _GLIBCXX_USE_WCHAR_T
1094   inline std::wstring
1095   path::generic_wstring() const
1096   { return generic_string<wchar_t>(); }
1097 #endif
1098 
1099 #ifdef _GLIBCXX_USE_CHAR8_T
1100   inline std::u8string
1101   path::generic_u8string() const
1102   { return generic_string<char8_t>(); }
1103 #else
1104   inline std::string
1105   path::generic_u8string() const
1106   { return generic_string(); }
1107 #endif
1108 
1109   inline std::u16string
1110   path::generic_u16string() const
1111   { return generic_string<char16_t>(); }
1112 
1113   inline std::u32string
1114   path::generic_u32string() const
1115   { return generic_string<char32_t>(); }
1116 
1117   inline int
1118   path::compare(const string_type& __s) const noexcept
1119   { return compare(basic_string_view<value_type>(__s)); }
1120 
1121   inline int
1122   path::compare(const value_type* __s) const noexcept
1123   { return compare(basic_string_view<value_type>(__s)); }
1124 
1125   inline path
1126   path::filename() const
1127   {
1128     if (empty())
1129       return {};
1130     else if (_M_type() == _Type::_Filename)
1131       return *this;
1132     else if (_M_type() == _Type::_Multi)
1133       {
1134 	if (_M_pathname.back() == preferred_separator)
1135 	  return {};
1136 	auto& __last = *--end();
1137 	if (__last._M_type() == _Type::_Filename)
1138 	  return __last;
1139       }
1140     return {};
1141   }
1142 
1143   inline path
1144   path::stem() const
1145   {
1146     auto ext = _M_find_extension();
1147     if (ext.first && ext.second != 0)
1148       return path{ext.first->substr(0, ext.second)};
1149     return {};
1150   }
1151 
1152   inline path
1153   path::extension() const
1154   {
1155     auto ext = _M_find_extension();
1156     if (ext.first && ext.second != string_type::npos)
1157       return path{ext.first->substr(ext.second)};
1158     return {};
1159   }
1160 
1161   inline bool
1162   path::has_stem() const noexcept
1163   {
1164     auto ext = _M_find_extension();
1165     return ext.first && ext.second != 0;
1166   }
1167 
1168   inline bool
1169   path::has_extension() const noexcept
1170   {
1171     auto ext = _M_find_extension();
1172     return ext.first && ext.second != string_type::npos;
1173   }
1174 
1175   inline bool
1176   path::is_absolute() const noexcept
1177   {
1178 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1179     return has_root_name() && has_root_directory();
1180 #else
1181     return has_root_directory();
1182 #endif
1183   }
1184 
1185   inline path::iterator
1186   path::begin() const
1187   {
1188     if (_M_type() == _Type::_Multi)
1189       return iterator(this, _M_cmpts.begin());
1190     return iterator(this, empty());
1191   }
1192 
1193   inline path::iterator
1194   path::end() const
1195   {
1196     if (_M_type() == _Type::_Multi)
1197       return iterator(this, _M_cmpts.end());
1198     return iterator(this, true);
1199   }
1200 
1201   inline path::iterator&
1202   path::iterator::operator++()
1203   {
1204     __glibcxx_assert(_M_path != nullptr);
1205     if (_M_path->_M_type() == _Type::_Multi)
1206       {
1207 	__glibcxx_assert(_M_cur != _M_path->_M_cmpts.end());
1208 	++_M_cur;
1209       }
1210     else
1211       {
1212 	__glibcxx_assert(!_M_at_end);
1213 	_M_at_end = true;
1214       }
1215     return *this;
1216   }
1217 
1218   inline path::iterator&
1219   path::iterator::operator--()
1220   {
1221     __glibcxx_assert(_M_path != nullptr);
1222     if (_M_path->_M_type() == _Type::_Multi)
1223       {
1224 	__glibcxx_assert(_M_cur != _M_path->_M_cmpts.begin());
1225 	--_M_cur;
1226       }
1227     else
1228       {
1229 	__glibcxx_assert(_M_at_end);
1230 	_M_at_end = false;
1231       }
1232     return *this;
1233   }
1234 
1235   inline path::iterator::reference
1236   path::iterator::operator*() const
1237   {
1238     __glibcxx_assert(_M_path != nullptr);
1239     if (_M_path->_M_type() == _Type::_Multi)
1240       {
1241 	__glibcxx_assert(_M_cur != _M_path->_M_cmpts.end());
1242 	return *_M_cur;
1243       }
1244     return *_M_path;
1245   }
1246 
1247   inline bool
1248   path::iterator::_M_equals(iterator __rhs) const
1249   {
1250     if (_M_path != __rhs._M_path)
1251       return false;
1252     if (_M_path == nullptr)
1253       return true;
1254     if (_M_path->_M_type() == path::_Type::_Multi)
1255       return _M_cur == __rhs._M_cur;
1256     return _M_at_end == __rhs._M_at_end;
1257   }
1258 
1259   // @} group filesystem
1260 _GLIBCXX_END_NAMESPACE_CXX11
1261 } // namespace filesystem
1262 
1263 inline ptrdiff_t
1264 distance(filesystem::path::iterator __first, filesystem::path::iterator __last)
1265 { return __path_iter_distance(__first, __last); }
1266 
1267 template<typename _InputIterator, typename _Distance>
1268   void
1269   advance(filesystem::path::iterator& __i, _Distance __n)
1270   { __path_iter_advance(__i, static_cast<ptrdiff_t>(__n)); }
1271 
1272 extern template class __shared_ptr<const filesystem::filesystem_error::_Impl>;
1273 
1274 _GLIBCXX_END_NAMESPACE_VERSION
1275 } // namespace std
1276 
1277 #endif // C++17
1278 
1279 #endif // _GLIBCXX_FS_PATH_H
1280