build-system-toy/ghc/filesystem.hpp

//---------------------------------------------------------------------------------------
//
// ghc::filesystem - A C++17-like filesystem implementation for
// C++11/C++14/C++17
//
//---------------------------------------------------------------------------------------
//
// Copyright (c) 2018, Steffen Schümann <s.schuemann@pobox.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
//---------------------------------------------------------------------------------------
//
// To dynamically select std::filesystem where available, you could use:
//
// #if defined(__cplusplus) && __cplusplus >= 201703L && defined(__has_include)
// && __has_include(<filesystem>) #include <filesystem> namespace fs =
// std::filesystem; #else #include <ghc/filesystem.hpp> namespace fs =
// ghc::filesystem; #endif
//
//---------------------------------------------------------------------------------------
#ifndef GHC_FILESYSTEM_H
#define GHC_FILESYSTEM_H

// #define BSD manifest constant only in
// sys/param.h
#ifndef _WIN32
#include <sys/param.h>
#endif

#ifndef GHC_OS_DETECTED
#if defined(__APPLE__) && defined(__MACH__)
#define GHC_OS_MACOS
#elif defined(__linux__)
#define GHC_OS_LINUX
#if defined(__ANDROID__)
#define GHC_OS_ANDROID
#endif
#elif defined(_WIN64)
#define GHC_OS_WINDOWS
#define GHC_OS_WIN64
#elif defined(_WIN32)
#define GHC_OS_WINDOWS
#define GHC_OS_WIN32
#elif defined(__svr4__)
#define GHC_OS_SYS5R4
#elif defined(BSD)
#define GHC_OS_BSD
#elif defined(__EMSCRIPTEN__)
#define GHC_OS_WEB
#include <wasi/api.h>
#else
#error "Operating system currently not supported!"
#endif
#define GHC_OS_DETECTED
#endif

#if defined(GHC_FILESYSTEM_IMPLEMENTATION)
#define GHC_EXPAND_IMPL
#define GHC_INLINE
#ifdef GHC_OS_WINDOWS
#define GHC_FS_API
#define GHC_FS_API_CLASS
#else
#define GHC_FS_API __attribute__((visibility("default")))
#define GHC_FS_API_CLASS __attribute__((visibility("default")))
#endif
#elif defined(GHC_FILESYSTEM_FWD)
#define GHC_INLINE
#ifdef GHC_OS_WINDOWS
#define GHC_FS_API extern
#define GHC_FS_API_CLASS
#else
#define GHC_FS_API extern
#define GHC_FS_API_CLASS
#endif
#else
#define GHC_EXPAND_IMPL
#define GHC_INLINE inline
#define GHC_FS_API
#define GHC_FS_API_CLASS
#endif

#ifdef GHC_EXPAND_IMPL

#ifdef GHC_OS_WINDOWS
#include <windows.h>
// additional includes
#include <shellapi.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <wchar.h>
#include <winioctl.h>
#else
#include <dirent.h>
#include <fcntl.h>
#include <limits.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#ifdef GHC_OS_ANDROID
#include <android/api-level.h>
#if __ANDROID_API__ < 12
#include <sys/syscall.h>
#endif
#include <sys/vfs.h>
#define statvfs statfs
#else
#include <sys/statvfs.h>
#endif
#if !defined(__ANDROID__) || __ANDROID_API__ >= 26
#include <langinfo.h>
#endif
#endif
#ifdef GHC_OS_MACOS
#include <Availability.h>
#endif

#include <algorithm>
#include <cctype>
#include <chrono>
#include <clocale>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <functional>
#include <memory>
#include <stack>
#include <stdexcept>
#include <string>
#include <system_error>
#include <type_traits>
#include <utility>
#include <vector>

#else // GHC_EXPAND_IMPL
#include <chrono>
#include <fstream>
#include <memory>
#include <stack>
#include <stdexcept>
#include <string>
#include <system_error>
#ifdef GHC_OS_WINDOWS
#include <vector>
#endif
#endif // GHC_EXPAND_IMPL

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//- - - - - - - - -
// Behaviour Switches (see README.md, should match the config in
// test/filesystem_test.cpp):
//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//- - - - - - - - -
// LWG #2682 disables the since then invalid use of the copy option
// create_symlinks on directories configure LWG conformance ()
#define LWG_2682_BEHAVIOUR
//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//- - - - - - - - -
// LWG #2395 makes crate_directory/create_directories not emit an error if there
// is a regular file with that name, it is superceded by P1164R1, so only
// activate if really needed #define LWG_2935_BEHAVIOUR
//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//- - - - - - - - -
// LWG #2937 enforces that fs::equivalent emits an error, if
// !fs::exists(p1)||!exists(p2)
#define LWG_2937_BEHAVIOUR
//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//- - - - - - - - -
// UTF8-Everywhere is the original behaviour of ghc::filesystem. With this
// define you can enable the more standard conforming implementation option that
// uses wstring on Windows as ghc::filesystem::string_type. #define
// GHC_WIN_WSTRING_STRING_TYPE
//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//- - - - - - - - -
// Raise errors/exceptions when invalid unicode codepoints or UTF-8 sequences
// are found, instead of replacing them with the unicode replacement character
// (U+FFFD). #define GHC_RAISE_UNICODE_ERRORS
//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//- - - - - - - - -

// ghc::filesystem version in decimal (major * 10000 + minor * 100 + patch)
#define GHC_FILESYSTEM_VERSION 10304L

#if !defined(GHC_WITH_EXCEPTIONS) &&                                           \
    (defined(__EXCEPTIONS) || defined(__cpp_exceptions) ||                     \
     defined(_CPPUNWIND))
#define GHC_WITH_EXCEPTIONS
#endif
#if !defined(GHC_WITH_EXCEPTIONS) && defined(GHC_RAISE_UNICODE_ERRORS)
#error "Can't raise unicode errors whith exception support disabled"
#endif

namespace ghc { namespace filesystem {

  // temporary existing exception type for yet unimplemented parts
  class GHC_FS_API_CLASS not_implemented_exception : public std::logic_error {
  public:
    not_implemented_exception()
        : std::logic_error("function not implemented yet.") {}
  };

  template <typename char_type> class path_helper_base {
  public:
    using value_type = char_type;
#ifdef GHC_OS_WINDOWS
    static constexpr value_type preferred_separator = '\\';
#else
    static constexpr value_type preferred_separator = '/';
#endif
  };

#if __cplusplus < 201703L
  template <typename char_type>
  constexpr char_type path_helper_base<char_type>::preferred_separator;
#endif

  // 30.10.8 class path
  class GHC_FS_API_CLASS path
#if defined(GHC_OS_WINDOWS) && defined(GHC_WIN_WSTRING_STRING_TYPE)
#define GHC_USE_WCHAR_T
      : private path_helper_base<std::wstring::value_type> {
  public:
    using path_helper_base<std::wstring::value_type>::value_type;
#else
      : private path_helper_base<std::string::value_type> {
  public:
    using path_helper_base<std::string::value_type>::value_type;
#endif
    using string_type = std::basic_string<value_type>;
    using path_helper_base<value_type>::preferred_separator;

    // 30.10.10.1 enumeration format
    /// The path format in wich the constructor argument is given.
    enum format {
      generic_format, ///< The generic format, internally used by
                      ///< ghc::filesystem::path with slashes
      native_format,  ///< The format native to the current platform this code
                      ///< is build for
      auto_format,    ///< Try to auto-detect the format, fallback to native
    };

    template <class T> struct _is_basic_string : std::false_type {};
    template <class CharT, class Traits, class Alloc>
    struct _is_basic_string<std::basic_string<CharT, Traits, Alloc>>
        : std::true_type {};
#ifdef __cpp_lib_string_view
    template <class CharT>
    struct _is_basic_string<std::basic_string_view<CharT>> : std::true_type {};
#endif

    template <typename T1, typename T2 = void>
    using path_type =
        typename std::enable_if<!std::is_same<path, T1>::value, path>::type;
#ifdef GHC_USE_WCHAR_T
    template <typename T>
    using path_from_string = typename std::enable_if<
        _is_basic_string<T>::value ||
            std::is_same<char const *, typename std::decay<T>::type>::value ||
            std::is_same<char *, typename std::decay<T>::type>::value ||
            std::is_same<wchar_t const *,
                         typename std::decay<T>::type>::value ||
            std::is_same<wchar_t *, typename std::decay<T>::type>::value,
        path>::type;
    template <typename T>
    using path_type_EcharT =
        typename std::enable_if<std::is_same<T, char>::value ||
                                    std::is_same<T, char16_t>::value ||
                                    std::is_same<T, char32_t>::value,
                                path>::type;
#else
    template <typename T>
    using path_from_string = typename std::enable_if<
        _is_basic_string<T>::value ||
            std::is_same<char const *, typename std::decay<T>::type>::value ||
            std::is_same<char *, typename std::decay<T>::type>::value,
        path>::type;
    template <typename T>
    using path_type_EcharT = typename std::enable_if<
        std::is_same<T, char>::value || std::is_same<T, char16_t>::value ||
            std::is_same<T, char32_t>::value || std::is_same<T, wchar_t>::value,
        path>::type;
#endif
    // 30.10.8.4.1 constructors and destructor
    path() noexcept;
    path(const path & p);
    path(path && p) noexcept;
    path(string_type && source, format fmt = auto_format);
    template <class Source, typename = path_from_string<Source>>
    path(const Source & source, format fmt = auto_format);
    template <class InputIterator>
    path(InputIterator first, InputIterator last, format fmt = auto_format);
#ifdef GHC_WITH_EXCEPTIONS
    template <class Source, typename = path_from_string<Source>>
    path(const Source & source, const std::locale & loc,
         format fmt = auto_format);
    template <class InputIterator>
    path(InputIterator first, InputIterator last, const std::locale & loc,
         format fmt = auto_format);
#endif
    ~path();

    // 30.10.8.4.2 assignments
    path & operator=(const path & p);
    path & operator=(path && p) noexcept;
    path & operator=(string_type && source);
    path & assign(string_type && source);
    template <class Source> path & operator=(const Source & source);
    template <class Source> path & assign(const Source & source);
    template <class InputIterator>
    path & assign(InputIterator first, InputIterator last);

    // 30.10.8.4.3 appends
    path & operator/=(const path & p);
    template <class Source> path & operator/=(const Source & source);
    template <class Source> path & append(const Source & source);
    template <class InputIterator>
    path & append(InputIterator first, InputIterator last);

    // 30.10.8.4.4 concatenation
    path & operator+=(const path & x);
    path & operator+=(const string_type & x);
#ifdef __cpp_lib_string_view
    path & operator+=(std::basic_string_view<value_type> x);
#endif
    path & operator+=(const value_type * x);
    path & operator+=(value_type x);
    template <class Source>
    path_from_string<Source> & operator+=(const Source & x);
    template <class EcharT> path_type_EcharT<EcharT> & operator+=(EcharT x);
    template <class Source> path & concat(const Source & x);
    template <class InputIterator>
    path & concat(InputIterator first, InputIterator last);

    // 30.10.8.4.5 modifiers
    void clear() noexcept;
    path & make_preferred();
    path & remove_filename();
    path & replace_filename(const path & replacement);
    path & replace_extension(const path & replacement = path());
    void swap(path & rhs) noexcept;

    // 30.10.8.4.6 native format observers
    const string_type &
    native() const; // this implementation doesn't support noexcept for native()
    const value_type *
    c_str() const; // this implementation doesn't support noexcept for c_str()
    operator string_type() const;
    template <class EcharT, class traits = std::char_traits<EcharT>,
              class Allocator = std::allocator<EcharT>>
    std::basic_string<EcharT, traits, Allocator>
    string(const Allocator & a = Allocator()) const;
    std::string string() const;
    std::wstring wstring() const;
    std::string u8string() const;
    std::u16string u16string() const;
    std::u32string u32string() const;

    // 30.10.8.4.7 generic format observers
    template <class EcharT, class traits = std::char_traits<EcharT>,
              class Allocator = std::allocator<EcharT>>
    std::basic_string<EcharT, traits, Allocator>
    generic_string(const Allocator & a = Allocator()) const;
    const std::string & generic_string()
        const; // this is different from the standard, that returns by value
    std::wstring generic_wstring() const;
    std::string generic_u8string() const;
    std::u16string generic_u16string() const;
    std::u32string generic_u32string() const;

    // 30.10.8.4.8 compare
    int compare(const path & p) const noexcept;
    int compare(const string_type & s) const;
#ifdef __cpp_lib_string_view
    int compare(std::basic_string_view<value_type> s) const;
#endif
    int compare(const value_type * s) const;

    // 30.10.8.4.9 decomposition
    path root_name() const;
    path root_directory() const;
    path root_path() const;
    path relative_path() const;
    path parent_path() const;
    path filename() const;
    path stem() const;
    path extension() const;

    // 30.10.8.4.10 query
    bool empty() const noexcept;
    bool has_root_name() const;
    bool has_root_directory() const;
    bool has_root_path() const;
    bool has_relative_path() const;
    bool has_parent_path() const;
    bool has_filename() const;
    bool has_stem() const;
    bool has_extension() const;
    bool is_absolute() const;
    bool is_relative() const;

    // 30.10.8.4.11 generation
    path lexically_normal() const;
    path lexically_relative(const path & base) const;
    path lexically_proximate(const path & base) const;

    // 30.10.8.5 iterators
    class iterator;
    using const_iterator = iterator;
    iterator begin() const;
    iterator end() const;

  private:
    using impl_value_type = std::string::value_type;
    using impl_string_type = std::basic_string<impl_value_type>;
    friend class directory_iterator;
    void append_name(const char * name);
    static constexpr impl_value_type generic_separator = '/';
    template <typename InputIterator> class input_iterator_range {
    public:
      typedef InputIterator iterator;
      typedef InputIterator const_iterator;
      typedef typename InputIterator::difference_type difference_type;

      input_iterator_range(const InputIterator & first,
                           const InputIterator & last)
          : _first(first), _last(last) {}

      InputIterator begin() const { return _first; }
      InputIterator end() const { return _last; }

    private:
      InputIterator _first;
      InputIterator _last;
    };
    friend void swap(path & lhs, path & rhs) noexcept;
    friend size_t hash_value(const path & p) noexcept;
    static void postprocess_path_with_format(impl_string_type & p, format fmt);
    impl_string_type _path;
#ifdef GHC_OS_WINDOWS
    impl_string_type native_impl() const;
    mutable string_type _native_cache;
#else
    const impl_string_type & native_impl() const;
#endif
  };

  // 30.10.8.6 path non-member functions
  GHC_FS_API void swap(path & lhs, path & rhs) noexcept;
  GHC_FS_API size_t hash_value(const path & p) noexcept;
  GHC_FS_API bool operator==(const path & lhs, const path & rhs) noexcept;
  GHC_FS_API bool operator!=(const path & lhs, const path & rhs) noexcept;
  GHC_FS_API bool operator<(const path & lhs, const path & rhs) noexcept;
  GHC_FS_API bool operator<=(const path & lhs, const path & rhs) noexcept;
  GHC_FS_API bool operator>(const path & lhs, const path & rhs) noexcept;
  GHC_FS_API bool operator>=(const path & lhs, const path & rhs) noexcept;

  GHC_FS_API path operator/(const path & lhs, const path & rhs);

  // 30.10.8.6.1 path inserter and extractor
  template <class charT, class traits>
  std::basic_ostream<charT, traits> &
  operator<<(std::basic_ostream<charT, traits> & os, const path & p);
  template <class charT, class traits>
  std::basic_istream<charT, traits> &
  operator>>(std::basic_istream<charT, traits> & is, path & p);

  // 30.10.8.6.2 path factory functions
  template <class Source, typename = path::path_from_string<Source>>
  path u8path(const Source & source);
  template <class InputIterator>
  path u8path(InputIterator first, InputIterator last);

  // 30.10.9 class filesystem_error
  class GHC_FS_API_CLASS filesystem_error : public std::system_error {
  public:
    filesystem_error(const std::string & what_arg, std::error_code ec);
    filesystem_error(const std::string & what_arg, const path & p1,
                     std::error_code ec);
    filesystem_error(const std::string & what_arg, const path & p1,
                     const path & p2, std::error_code ec);
    const path & path1() const noexcept;
    const path & path2() const noexcept;
    const char * what() const noexcept override;

  private:
    std::string _what_arg;
    std::error_code _ec;
    path _p1, _p2;
  };

  class GHC_FS_API_CLASS path::iterator {
  public:
    using value_type = const path;
    using difference_type = std::ptrdiff_t;
    using pointer = const path *;
    using reference = const path &;
    using iterator_category = std::bidirectional_iterator_tag;

    iterator();
    iterator(const impl_string_type::const_iterator & first,
             const impl_string_type::const_iterator & last,
             const impl_string_type::const_iterator & pos);
    iterator & operator++();
    iterator operator++(int);
    iterator & operator--();
    iterator operator--(int);
    bool operator==(const iterator & other) const;
    bool operator!=(const iterator & other) const;
    reference operator*() const;
    pointer operator->() const;

  private:
    impl_string_type::const_iterator
    increment(const std::string::const_iterator & pos) const;
    impl_string_type::const_iterator
    decrement(const std::string::const_iterator & pos) const;
    void updateCurrent();
    impl_string_type::const_iterator _first;
    impl_string_type::const_iterator _last;
    impl_string_type::const_iterator _root;
    impl_string_type::const_iterator _iter;
    path _current;
  };

  struct space_info {
    uintmax_t capacity;
    uintmax_t free;
    uintmax_t available;
  };

  // 30.10.10, enumerations
  enum class file_type {
    none,
    not_found,
    regular,
    directory,
    symlink,
    block,
    character,
    fifo,
    socket,
    unknown,
  };

  enum class perms : uint16_t {
    none = 0,

    owner_read = 0400,
    owner_write = 0200,
    owner_exec = 0100,
    owner_all = 0700,

    group_read = 040,
    group_write = 020,
    group_exec = 010,
    group_all = 070,

    others_read = 04,
    others_write = 02,
    others_exec = 01,
    others_all = 07,

    all = 0777,
    set_uid = 04000,
    set_gid = 02000,
    sticky_bit = 01000,

    mask = 07777,
    unknown = 0xffff
  };

  enum class perm_options : uint16_t {
    replace = 3,
    add = 1,
    remove = 2,
    nofollow = 4,
  };

  enum class copy_options : uint16_t {
    none = 0,

    skip_existing = 1,
    overwrite_existing = 2,
    update_existing = 4,

    recursive = 8,

    copy_symlinks = 0x10,
    skip_symlinks = 0x20,

    directories_only = 0x40,
    create_symlinks = 0x80,
#ifndef GHC_OS_WEB
    create_hard_links = 0x100
#endif
  };

  enum class directory_options : uint16_t {
    none = 0,
    follow_directory_symlink = 1,
    skip_permission_denied = 2,
  };

  // 30.10.11 class file_status
  class GHC_FS_API_CLASS file_status {
  public:
    // 30.10.11.1 constructors and destructor
    file_status() noexcept;
    explicit file_status(file_type ft, perms prms = perms::unknown) noexcept;
    file_status(const file_status &) noexcept;
    file_status(file_status &&) noexcept;
    ~file_status();
    // assignments:
    file_status & operator=(const file_status &) noexcept;
    file_status & operator=(file_status &&) noexcept;
    // 30.10.11.3 modifiers
    void type(file_type ft) noexcept;
    void permissions(perms prms) noexcept;
    // 30.10.11.2 observers
    file_type type() const noexcept;
    perms permissions() const noexcept;

  private:
    file_type _type;
    perms _perms;
  };

  using file_time_type = std::chrono::time_point<std::chrono::system_clock>;

  // 30.10.12 Class directory_entry
  class GHC_FS_API_CLASS directory_entry {
  public:
    // 30.10.12.1 constructors and destructor
    directory_entry() noexcept = default;
    directory_entry(const directory_entry &) = default;
    directory_entry(directory_entry &&) noexcept = default;
#ifdef GHC_WITH_EXCEPTIONS
    explicit directory_entry(const path & p);
#endif
    directory_entry(const path & p, std::error_code & ec);
    ~directory_entry();

    // assignments:
    directory_entry & operator=(const directory_entry &) = default;
    directory_entry & operator=(directory_entry &&) noexcept = default;

    // 30.10.12.2 modifiers
#ifdef GHC_WITH_EXCEPTIONS
    void assign(const path & p);
#endif
    void assign(const path & p, std::error_code & ec);
#ifdef GHC_WITH_EXCEPTIONS
    void replace_filename(const path & p);
#endif
    void replace_filename(const path & p, std::error_code & ec);
#ifdef GHC_WITH_EXCEPTIONS
    void refresh();
#endif
    void refresh(std::error_code & ec) noexcept;

    // 30.10.12.3 observers
    const filesystem::path & path() const noexcept;
    operator const filesystem::path &() const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool exists() const;
#endif
    bool exists(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool is_block_file() const;
#endif
    bool is_block_file(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool is_character_file() const;
#endif
    bool is_character_file(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool is_directory() const;
#endif
    bool is_directory(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool is_fifo() const;
#endif
    bool is_fifo(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool is_other() const;
#endif
    bool is_other(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool is_regular_file() const;
#endif
    bool is_regular_file(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool is_socket() const;
#endif
    bool is_socket(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    bool is_symlink() const;
#endif
    bool is_symlink(std::error_code & ec) const noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    uintmax_t file_size() const;
#endif
    uintmax_t file_size(std::error_code & ec) const noexcept;

#ifndef GHC_OS_WEB
#ifdef GHC_WITH_EXCEPTIONS
    uintmax_t hard_link_count() const;
#endif
    uintmax_t hard_link_count(std::error_code & ec) const noexcept;
#endif

#ifdef GHC_WITH_EXCEPTIONS
    file_time_type last_write_time() const;
#endif
    file_time_type last_write_time(std::error_code & ec) const noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    file_status status() const;
#endif
    file_status status(std::error_code & ec) const noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    file_status symlink_status() const;
#endif
    file_status symlink_status(std::error_code & ec) const noexcept;
    bool operator<(const directory_entry & rhs) const noexcept;
    bool operator==(const directory_entry & rhs) const noexcept;
    bool operator!=(const directory_entry & rhs) const noexcept;
    bool operator<=(const directory_entry & rhs) const noexcept;
    bool operator>(const directory_entry & rhs) const noexcept;
    bool operator>=(const directory_entry & rhs) const noexcept;

  private:
    friend class directory_iterator;
    filesystem::path _path;
    file_status _status;
    file_status _symlink_status;
    uintmax_t _file_size = 0;
#ifndef GHC_OS_WINDOWS
    uintmax_t _hard_link_count = 0;
#endif
    time_t _last_write_time = 0;
  };

  // 30.10.13 Class directory_iterator
  class GHC_FS_API_CLASS directory_iterator {
  public:
    class GHC_FS_API_CLASS proxy {
    public:
      const directory_entry & operator*() const & noexcept {
        return _dir_entry;
      }
      directory_entry operator*() && noexcept { return std::move(_dir_entry); }

    private:
      explicit proxy(const directory_entry & dir_entry)
          : _dir_entry(dir_entry) {}
      friend class directory_iterator;
      friend class recursive_directory_iterator;
      directory_entry _dir_entry;
    };
    using iterator_category = std::input_iterator_tag;
    using value_type = directory_entry;
    using difference_type = std::ptrdiff_t;
    using pointer = const directory_entry *;
    using reference = const directory_entry &;

    // 30.10.13.1 member functions
    directory_iterator() noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    explicit directory_iterator(const path & p);
    directory_iterator(const path & p, directory_options options);
#endif
    directory_iterator(const path & p, std::error_code & ec) noexcept;
    directory_iterator(const path & p, directory_options options,
                       std::error_code & ec) noexcept;
    directory_iterator(const directory_iterator & rhs);
    directory_iterator(directory_iterator && rhs) noexcept;
    ~directory_iterator();
    directory_iterator & operator=(const directory_iterator & rhs);
    directory_iterator & operator=(directory_iterator && rhs) noexcept;
    const directory_entry & operator*() const;
    const directory_entry * operator->() const;
#ifdef GHC_WITH_EXCEPTIONS
    directory_iterator & operator++();
#endif
    directory_iterator & increment(std::error_code & ec) noexcept;

    // other members as required by 27.2.3, input iterators
#ifdef GHC_WITH_EXCEPTIONS
    proxy operator++(int) {
      proxy p{**this};
      ++*this;
      return p;
    }
#endif
    bool operator==(const directory_iterator & rhs) const;
    bool operator!=(const directory_iterator & rhs) const;

  private:
    friend class recursive_directory_iterator;
    class impl;
    std::shared_ptr<impl> _impl;
  };

  // 30.10.13.2 directory_iterator non-member functions
  GHC_FS_API directory_iterator begin(directory_iterator iter) noexcept;
  GHC_FS_API directory_iterator end(const directory_iterator &) noexcept;

  // 30.10.14 class recursive_directory_iterator
  class GHC_FS_API_CLASS recursive_directory_iterator {
  public:
    using iterator_category = std::input_iterator_tag;
    using value_type = directory_entry;
    using difference_type = std::ptrdiff_t;
    using pointer = const directory_entry *;
    using reference = const directory_entry &;

    // 30.10.14.1 constructors and destructor
    recursive_directory_iterator() noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    explicit recursive_directory_iterator(const path & p);
    recursive_directory_iterator(const path & p, directory_options options);
#endif
    recursive_directory_iterator(const path & p, directory_options options,
                                 std::error_code & ec) noexcept;
    recursive_directory_iterator(const path & p, std::error_code & ec) noexcept;
    recursive_directory_iterator(const recursive_directory_iterator & rhs);
    recursive_directory_iterator(recursive_directory_iterator && rhs) noexcept;
    ~recursive_directory_iterator();

    // 30.10.14.1 observers
    directory_options options() const;
    int depth() const;
    bool recursion_pending() const;

    const directory_entry & operator*() const;
    const directory_entry * operator->() const;

    // 30.10.14.1 modifiers recursive_directory_iterator&
    recursive_directory_iterator &
    operator=(const recursive_directory_iterator & rhs);
    recursive_directory_iterator &
    operator=(recursive_directory_iterator && rhs) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    recursive_directory_iterator & operator++();
#endif
    recursive_directory_iterator & increment(std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    void pop();
#endif
    void pop(std::error_code & ec);
    void disable_recursion_pending();

    // other members as required by 27.2.3, input iterators
#ifdef GHC_WITH_EXCEPTIONS
    directory_iterator::proxy operator++(int) {
      directory_iterator::proxy proxy{**this};
      ++*this;
      return proxy;
    }
#endif
    bool operator==(const recursive_directory_iterator & rhs) const;
    bool operator!=(const recursive_directory_iterator & rhs) const;

  private:
    struct recursive_directory_iterator_impl {
      directory_options _options;
      bool _recursion_pending;
      std::stack<directory_iterator> _dir_iter_stack;
      recursive_directory_iterator_impl(directory_options options,
                                        bool recursion_pending)
          : _options(options), _recursion_pending(recursion_pending) {}
    };
    std::shared_ptr<recursive_directory_iterator_impl> _impl;
  };

  // 30.10.14.2 directory_iterator non-member functions
  GHC_FS_API recursive_directory_iterator
  begin(recursive_directory_iterator iter) noexcept;
  GHC_FS_API recursive_directory_iterator
  end(const recursive_directory_iterator &) noexcept;

// 30.10.15 filesystem operations
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API path absolute(const path & p);
#endif
    GHC_FS_API path absolute(const path & p, std::error_code & ec);

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API path canonical(const path & p);
#endif
    GHC_FS_API path canonical(const path & p, std::error_code & ec);

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void copy(const path & from, const path & to);
#endif
    GHC_FS_API void copy(const path & from, const path & to,
                         std::error_code & ec) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void copy(const path & from, const path & to,
                         copy_options options);
#endif
    GHC_FS_API void copy(const path & from, const path & to,
                         copy_options options, std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool copy_file(const path & from, const path & to);
#endif
    GHC_FS_API bool copy_file(const path & from, const path & to,
                              std::error_code & ec) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool copy_file(const path & from, const path & to,
                              copy_options option);
#endif
    GHC_FS_API bool copy_file(const path & from, const path & to,
                              copy_options option,
                              std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void copy_symlink(const path & existing_symlink,
                                 const path & new_symlink);
#endif
    GHC_FS_API void copy_symlink(const path & existing_symlink,
                                 const path & new_symlink,
                                 std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool create_directories(const path & p);
#endif
    GHC_FS_API bool create_directories(const path & p,
                                       std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool create_directory(const path & p);
#endif
    GHC_FS_API bool create_directory(const path & p,
                                     std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool create_directory(const path & p, const path & attributes);
#endif
    GHC_FS_API bool create_directory(const path & p, const path & attributes,
                                     std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void create_directory_symlink(const path & to,
                                             const path & new_symlink);
#endif
    GHC_FS_API void create_directory_symlink(const path & to,
                                             const path & new_symlink,
                                             std::error_code & ec) noexcept;

#ifndef GHC_OS_WEB
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void create_hard_link(const path & to,
                                     const path & new_hard_link);
#endif
    GHC_FS_API void create_hard_link(const path & to,
                                     const path & new_hard_link,
                                     std::error_code & ec) noexcept;
#endif

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void create_symlink(const path & to, const path & new_symlink);
#endif
    GHC_FS_API void create_symlink(const path & to, const path & new_symlink,
                                   std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API path current_path();
#endif
    GHC_FS_API path current_path(std::error_code & ec);
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void current_path(const path & p);
#endif
    GHC_FS_API void current_path(const path & p, std::error_code & ec) noexcept;

    GHC_FS_API bool exists(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool exists(const path & p);
#endif
    GHC_FS_API bool exists(const path & p, std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool equivalent(const path & p1, const path & p2);
#endif
    GHC_FS_API bool equivalent(const path & p1, const path & p2,
                               std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API uintmax_t file_size(const path & p);
#endif
    GHC_FS_API uintmax_t file_size(const path & p,
                                   std::error_code & ec) noexcept;

#ifndef GHC_OS_WEB
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API uintmax_t hard_link_count(const path & p);
#endif
    GHC_FS_API uintmax_t hard_link_count(const path & p,
                                         std::error_code & ec) noexcept;
#endif

    GHC_FS_API bool is_block_file(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_block_file(const path & p);
#endif
    GHC_FS_API bool is_block_file(const path & p,
                                  std::error_code & ec) noexcept;
    GHC_FS_API bool is_character_file(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_character_file(const path & p);
#endif
    GHC_FS_API bool is_character_file(const path & p,
                                      std::error_code & ec) noexcept;
    GHC_FS_API bool is_directory(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_directory(const path & p);
#endif
    GHC_FS_API bool is_directory(const path & p, std::error_code & ec) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_empty(const path & p);
#endif
    GHC_FS_API bool is_empty(const path & p, std::error_code & ec) noexcept;
    GHC_FS_API bool is_fifo(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_fifo(const path & p);
#endif
    GHC_FS_API bool is_fifo(const path & p, std::error_code & ec) noexcept;
    GHC_FS_API bool is_other(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_other(const path & p);
#endif
    GHC_FS_API bool is_other(const path & p, std::error_code & ec) noexcept;
    GHC_FS_API bool is_regular_file(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_regular_file(const path & p);
#endif
    GHC_FS_API bool is_regular_file(const path & p,
                                    std::error_code & ec) noexcept;
    GHC_FS_API bool is_socket(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_socket(const path & p);
#endif
    GHC_FS_API bool is_socket(const path & p, std::error_code & ec) noexcept;
    GHC_FS_API bool is_symlink(file_status s) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool is_symlink(const path & p);
#endif
    GHC_FS_API bool is_symlink(const path & p, std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API file_time_type last_write_time(const path & p);
#endif
    GHC_FS_API file_time_type last_write_time(const path & p,
                                              std::error_code & ec) noexcept;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void last_write_time(const path & p, file_time_type new_time);
#endif
    GHC_FS_API void last_write_time(const path & p, file_time_type new_time,
                                    std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void permissions(const path & p, perms prms,
                                perm_options opts = perm_options::replace);
#endif
    GHC_FS_API void permissions(const path & p, perms prms,
                                std::error_code & ec) noexcept;
    GHC_FS_API void permissions(const path & p, perms prms, perm_options opts,
                                std::error_code & ec);

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API path proximate(const path & p, std::error_code & ec);
    GHC_FS_API path proximate(const path & p,
                              const path & base = current_path());
#endif
    GHC_FS_API path proximate(const path & p, const path & base,
                              std::error_code & ec);

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API path read_symlink(const path & p);
#endif
    GHC_FS_API path read_symlink(const path & p, std::error_code & ec);

    GHC_FS_API path relative(const path & p, std::error_code & ec);
#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API path relative(const path & p,
                             const path & base = current_path());
#endif
    GHC_FS_API path relative(const path & p, const path & base,
                             std::error_code & ec);

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API bool remove(const path & p);
#endif
    GHC_FS_API bool remove(const path & p, std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API uintmax_t remove_all(const path & p);
#endif
    GHC_FS_API uintmax_t remove_all(const path & p,
                                    std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void rename(const path & from, const path & to);
#endif
    GHC_FS_API void rename(const path & from, const path & to,
                           std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API void resize_file(const path & p, uintmax_t size);
#endif
    GHC_FS_API void resize_file(const path & p, uintmax_t size,
                                std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API space_info space(const path & p);
#endif
    GHC_FS_API space_info space(const path & p, std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API file_status status(const path & p);
#endif
    GHC_FS_API file_status status(const path & p,
                                  std::error_code & ec) noexcept;

    GHC_FS_API bool status_known(file_status s) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API file_status symlink_status(const path & p);
#endif
    GHC_FS_API file_status symlink_status(const path & p,
                                          std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API path temp_directory_path();
#endif
    GHC_FS_API path temp_directory_path(std::error_code & ec) noexcept;

#ifdef GHC_WITH_EXCEPTIONS
    GHC_FS_API path weakly_canonical(const path & p);
#endif
    GHC_FS_API path weakly_canonical(const path & p,
                                     std::error_code & ec) noexcept;

    // Non-C++17 add-on std::fstream wrappers with path
    template <class charT, class traits = std::char_traits<charT>>
    class basic_filebuf : public std::basic_filebuf<charT, traits> {
    public:
      basic_filebuf() {}
      ~basic_filebuf() override {}
      basic_filebuf(const basic_filebuf &) = delete;
      const basic_filebuf & operator=(const basic_filebuf &) = delete;
      basic_filebuf<charT, traits> * open(const path & p,
                                          std::ios_base::openmode mode) {
#if defined(GHC_OS_WINDOWS) && !defined(__GLIBCXX__)
        return std::basic_filebuf<charT, traits>::open(p.wstring().c_str(),
                                                       mode)
                   ? this
                   : 0;
#else
        return std::basic_filebuf<charT, traits>::open(p.string().c_str(), mode)
                   ? this
                   : 0;
#endif
      }
    };

    template <class charT, class traits = std::char_traits<charT>>
    class basic_ifstream : public std::basic_ifstream<charT, traits> {
    public:
      basic_ifstream() {}
#if defined(GHC_OS_WINDOWS) && !defined(__GLIBCXX__)
      explicit basic_ifstream(const path & p,
                              std::ios_base::openmode mode = std::ios_base::in)
          : std::basic_ifstream<charT, traits>(p.wstring().c_str(), mode) {}
      void open(const path & p,
                std::ios_base::openmode mode = std::ios_base::in) {
        std::basic_ifstream<charT, traits>::open(p.wstring().c_str(), mode);
      }
#else
      explicit basic_ifstream(const path & p,
                              std::ios_base::openmode mode = std::ios_base::in)
          : std::basic_ifstream<charT, traits>(p.string().c_str(), mode) {}
      void open(const path & p,
                std::ios_base::openmode mode = std::ios_base::in) {
        std::basic_ifstream<charT, traits>::open(p.string().c_str(), mode);
      }
#endif
      basic_ifstream(const basic_ifstream &) = delete;
      const basic_ifstream & operator=(const basic_ifstream &) = delete;
      ~basic_ifstream() override {}
    };

    template <class charT, class traits = std::char_traits<charT>>
    class basic_ofstream : public std::basic_ofstream<charT, traits> {
    public:
      basic_ofstream() {}
#if defined(GHC_OS_WINDOWS) && !defined(__GLIBCXX__)
      explicit basic_ofstream(const path & p,
                              std::ios_base::openmode mode = std::ios_base::out)
          : std::basic_ofstream<charT, traits>(p.wstring().c_str(), mode) {}
      void open(const path & p,
                std::ios_base::openmode mode = std::ios_base::out) {
        std::basic_ofstream<charT, traits>::open(p.wstring().c_str(), mode);
      }
#else
      explicit basic_ofstream(const path & p,
                              std::ios_base::openmode mode = std::ios_base::out)
          : std::basic_ofstream<charT, traits>(p.string().c_str(), mode) {}
      void open(const path & p,
                std::ios_base::openmode mode = std::ios_base::out) {
        std::basic_ofstream<charT, traits>::open(p.string().c_str(), mode);
      }
#endif
      basic_ofstream(const basic_ofstream &) = delete;
      const basic_ofstream & operator=(const basic_ofstream &) = delete;
      ~basic_ofstream() override {}
    };

    template <class charT, class traits = std::char_traits<charT>>
    class basic_fstream : public std::basic_fstream<charT, traits> {
    public:
      basic_fstream() {}
#if defined(GHC_OS_WINDOWS) && !defined(__GLIBCXX__)
      explicit basic_fstream(const path & p,
                             std::ios_base::openmode mode = std::ios_base::in |
                                                            std::ios_base::out)
          : std::basic_fstream<charT, traits>(p.wstring().c_str(), mode) {}
      void open(const path & p,
                std::ios_base::openmode mode = std::ios_base::in |
                                               std::ios_base::out) {
        std::basic_fstream<charT, traits>::open(p.wstring().c_str(), mode);
      }
#else
      explicit basic_fstream(const path & p,
                             std::ios_base::openmode mode = std::ios_base::in |
                                                            std::ios_base::out)
          : std::basic_fstream<charT, traits>(p.string().c_str(), mode) {}
      void open(const path & p,
                std::ios_base::openmode mode = std::ios_base::in |
                                               std::ios_base::out) {
        std::basic_fstream<charT, traits>::open(p.string().c_str(), mode);
      }
#endif
      basic_fstream(const basic_fstream &) = delete;
      const basic_fstream & operator=(const basic_fstream &) = delete;
      ~basic_fstream() override {}
    };

    typedef basic_filebuf<char> filebuf;
    typedef basic_filebuf<wchar_t> wfilebuf;
    typedef basic_ifstream<char> ifstream;
    typedef basic_ifstream<wchar_t> wifstream;
    typedef basic_ofstream<char> ofstream;
    typedef basic_ofstream<wchar_t> wofstream;
    typedef basic_fstream<char> fstream;
    typedef basic_fstream<wchar_t> wfstream;

    class GHC_FS_API_CLASS u8arguments {
    public:
      u8arguments(int & argc, char **& argv);
      ~u8arguments() {
        _refargc = _argc;
        _refargv = _argv;
      }

      bool valid() const { return _isvalid; }

    private:
      int _argc;
      char ** _argv;
      int & _refargc;
      char **& _refargv;
      bool _isvalid;
#ifdef GHC_OS_WINDOWS
      std::vector<std::string> _args;
      std::vector<char *> _argp;
#endif
    };

    //-------------------------------------------------------------------------------------------------
    //  Implementation
    //-------------------------------------------------------------------------------------------------

    namespace detail {
      // GHC_FS_API void postprocess_path_with_format(path::impl_string_type& p,
      // path::format fmt);
      enum utf8_states_t { S_STRT = 0, S_RJCT = 8 };
      GHC_FS_API void appendUTF8(std::string & str, uint32_t unicode);
      GHC_FS_API bool is_surrogate(uint32_t c);
      GHC_FS_API bool is_high_surrogate(uint32_t c);
      GHC_FS_API bool is_low_surrogate(uint32_t c);
      GHC_FS_API unsigned consumeUtf8Fragment(const unsigned state,
                                              const uint8_t fragment,
                                              uint32_t & codepoint);
      enum class portable_error {
        none = 0,
        exists,
        not_found,
        not_supported,
        not_implemented,
        invalid_argument,
        is_a_directory,
      };
      GHC_FS_API std::error_code make_error_code(portable_error err);
#ifdef GHC_OS_WINDOWS
      GHC_FS_API std::error_code make_system_error(uint32_t err = 0);
#else
      GHC_FS_API std::error_code make_system_error(int err = 0);
#endif
    } // namespace detail

    namespace detail {

#ifdef GHC_EXPAND_IMPL

      GHC_INLINE std::error_code make_error_code(portable_error err) {
#ifdef GHC_OS_WINDOWS
        switch (err) {
        case portable_error::none:
          return std::error_code();
        case portable_error::exists:
          return std::error_code(ERROR_ALREADY_EXISTS, std::system_category());
        case portable_error::not_found:
          return std::error_code(ERROR_PATH_NOT_FOUND, std::system_category());
        case portable_error::not_supported:
          return std::error_code(ERROR_NOT_SUPPORTED, std::system_category());
        case portable_error::not_implemented:
          return std::error_code(ERROR_CALL_NOT_IMPLEMENTED,
                                 std::system_category());
        case portable_error::invalid_argument:
          return std::error_code(ERROR_INVALID_PARAMETER,
                                 std::system_category());
        case portable_error::is_a_directory:
#ifdef ERROR_DIRECTORY_NOT_SUPPORTED
          return std::error_code(ERROR_DIRECTORY_NOT_SUPPORTED,
                                 std::system_category());
#else
          return std::error_code(ERROR_NOT_SUPPORTED, std::system_category());
#endif
        }
#else
        switch (err) {
        case portable_error::none:
          return std::error_code();
        case portable_error::exists:
          return std::error_code(EEXIST, std::system_category());
        case portable_error::not_found:
          return std::error_code(ENOENT, std::system_category());
        case portable_error::not_supported:
          return std::error_code(ENOTSUP, std::system_category());
        case portable_error::not_implemented:
          return std::error_code(ENOSYS, std::system_category());
        case portable_error::invalid_argument:
          return std::error_code(EINVAL, std::system_category());
        case portable_error::is_a_directory:
          return std::error_code(EISDIR, std::system_category());
        }
#endif
        return std::error_code();
      }

#ifdef GHC_OS_WINDOWS
      GHC_INLINE std::error_code make_system_error(uint32_t err) {
        return std::error_code(err ? static_cast<int>(err)
                                   : static_cast<int>(::GetLastError()),
                               std::system_category());
      }
#else
      GHC_INLINE std::error_code make_system_error(int err) {
        return std::error_code(err ? err : errno, std::system_category());
      }
#endif

#endif // GHC_EXPAND_IMPL

      template <typename Enum>
      using EnableBitmask = typename std::enable_if<
          std::is_same<Enum, perms>::value ||
              std::is_same<Enum, perm_options>::value ||
              std::is_same<Enum, copy_options>::value ||
              std::is_same<Enum, directory_options>::value,
          Enum>::type;
    } // namespace detail

    template <typename Enum>
    detail::EnableBitmask<Enum> operator&(Enum X, Enum Y) {
      using underlying = typename std::underlying_type<Enum>::type;
      return static_cast<Enum>(static_cast<underlying>(X) &
                               static_cast<underlying>(Y));
    }

    template <typename Enum>
    detail::EnableBitmask<Enum> operator|(Enum X, Enum Y) {
      using underlying = typename std::underlying_type<Enum>::type;
      return static_cast<Enum>(static_cast<underlying>(X) |
                               static_cast<underlying>(Y));
    }

    template <typename Enum>
    detail::EnableBitmask<Enum> operator^(Enum X, Enum Y) {
      using underlying = typename std::underlying_type<Enum>::type;
      return static_cast<Enum>(static_cast<underlying>(X) ^
                               static_cast<underlying>(Y));
    }

    template <typename Enum> detail::EnableBitmask<Enum> operator~(Enum X) {
      using underlying = typename std::underlying_type<Enum>::type;
      return static_cast<Enum>(~static_cast<underlying>(X));
    }

    template <typename Enum>
    detail::EnableBitmask<Enum> & operator&=(Enum & X, Enum Y) {
      X = X & Y;
      return X;
    }

    template <typename Enum>
    detail::EnableBitmask<Enum> & operator|=(Enum & X, Enum Y) {
      X = X | Y;
      return X;
    }

    template <typename Enum>
    detail::EnableBitmask<Enum> & operator^=(Enum & X, Enum Y) {
      X = X ^ Y;
      return X;
    }

#ifdef GHC_EXPAND_IMPL

    namespace detail {

      GHC_INLINE bool in_range(uint32_t c, uint32_t lo, uint32_t hi) {
        return (static_cast<uint32_t>(c - lo) < (hi - lo + 1));
      }

      GHC_INLINE bool is_surrogate(uint32_t c) {
        return in_range(c, 0xd800, 0xdfff);
      }

      GHC_INLINE bool is_high_surrogate(uint32_t c) {
        return (c & 0xfffffc00) == 0xd800;
      }

      GHC_INLINE bool is_low_surrogate(uint32_t c) {
        return (c & 0xfffffc00) == 0xdc00;
      }

      GHC_INLINE void appendUTF8(std::string & str, uint32_t unicode) {
        if (unicode <= 0x7f) {
          str.push_back(static_cast<char>(unicode));
        } else if (unicode >= 0x80 && unicode <= 0x7ff) {
          str.push_back(static_cast<char>((unicode >> 6) + 192));
          str.push_back(static_cast<char>((unicode & 0x3f) + 128));
        } else if ((unicode >= 0x800 && unicode <= 0xd7ff) ||
                   (unicode >= 0xe000 && unicode <= 0xffff)) {
          str.push_back(static_cast<char>((unicode >> 12) + 224));
          str.push_back(static_cast<char>(((unicode & 0xfff) >> 6) + 128));
          str.push_back(static_cast<char>((unicode & 0x3f) + 128));
        } else if (unicode >= 0x10000 && unicode <= 0x10ffff) {
          str.push_back(static_cast<char>((unicode >> 18) + 240));
          str.push_back(static_cast<char>(((unicode & 0x3ffff) >> 12) + 128));
          str.push_back(static_cast<char>(((unicode & 0xfff) >> 6) + 128));
          str.push_back(static_cast<char>((unicode & 0x3f) + 128));
        } else {
#ifdef GHC_RAISE_UNICODE_ERRORS
          throw filesystem_error(
              "Illegal code point for unicode character.", str,
              std::make_error_code(std::errc::illegal_byte_sequence));
#else
          appendUTF8(str, 0xfffd);
#endif
        }
      }

      // Thanks to Bjoern Hoehrmann
      // (https://bjoern.hoehrmann.de/utf-8/decoder/dfa/) and Taylor R Campbell
      // for the ideas to this DFA approach of UTF-8 decoding; Generating
      // debugging and shrinking my own DFA from scratch was a day of fun!
      GHC_INLINE unsigned consumeUtf8Fragment(const unsigned state,
                                              const uint8_t fragment,
                                              uint32_t & codepoint) {
        static const uint32_t utf8_state_info[] = {
            // encoded states
            0x11111111u, 0x11111111u, 0x77777777u, 0x77777777u, 0x88888888u,
            0x88888888u, 0x88888888u, 0x88888888u, 0x22222299u, 0x22222222u,
            0x22222222u, 0x22222222u, 0x3333333au, 0x33433333u, 0x9995666bu,
            0x99999999u, 0x88888880u, 0x22818108u, 0x88888881u, 0x88888882u,
            0x88888884u, 0x88888887u, 0x88888886u, 0x82218108u, 0x82281108u,
            0x88888888u, 0x88888883u, 0x88888885u, 0u,          0u,
            0u,          0u,
        };
        uint8_t category = fragment < 128
                               ? 0
                               : (utf8_state_info[(fragment >> 3) & 0xf] >>
                                  ((fragment & 7) << 2)) &
                                     0xf;
        codepoint = (state ? (codepoint << 6) | (fragment & 0x3fu)
                           : (0xffu >> category) & fragment);
        return state == S_RJCT
                   ? static_cast<unsigned>(S_RJCT)
                   : static_cast<unsigned>(
                         (utf8_state_info[category + 16] >> (state << 2)) &
                         0xf);
      }

      GHC_INLINE bool validUtf8(const std::string & utf8String) {
        std::string::const_iterator iter = utf8String.begin();
        unsigned utf8_state = S_STRT;
        std::uint32_t codepoint = 0;
        while (iter < utf8String.end()) {
          if ((utf8_state = consumeUtf8Fragment(utf8_state,
                                                static_cast<uint8_t>(*iter++),
                                                codepoint)) == S_RJCT) {
            return false;
          }
        }
        if (utf8_state) { return false; }
        return true;
      }

    } // namespace detail

#endif

    namespace detail {

      template <class StringType, typename std::enable_if<(
                                      sizeof(typename StringType::value_type) ==
                                      1)>::type * = nullptr>
      inline StringType
      fromUtf8(const std::string & utf8String,
               const typename StringType::allocator_type & alloc =
                   typename StringType::allocator_type()) {
        return StringType(utf8String.begin(), utf8String.end(), alloc);
      }

      template <class StringType, typename std::enable_if<(
                                      sizeof(typename StringType::value_type) ==
                                      2)>::type * = nullptr>
      inline StringType
      fromUtf8(const std::string & utf8String,
               const typename StringType::allocator_type & alloc =
                   typename StringType::allocator_type()) {
        StringType result(alloc);
        result.reserve(utf8String.length());
        std::string::const_iterator iter = utf8String.begin();
        unsigned utf8_state = S_STRT;
        std::uint32_t codepoint = 0;
        while (iter < utf8String.end()) {
          if ((utf8_state = consumeUtf8Fragment(utf8_state,
                                                static_cast<uint8_t>(*iter++),
                                                codepoint)) == S_STRT) {
            if (codepoint <= 0xffff) {
              result += static_cast<typename StringType::value_type>(codepoint);
            } else {
              codepoint -= 0x10000;
              result += static_cast<typename StringType::value_type>(
                  (codepoint >> 10) + 0xd800);
              result += static_cast<typename StringType::value_type>(
                  (codepoint & 0x3ff) + 0xdc00);
            }
            codepoint = 0;
          } else if (utf8_state == S_RJCT) {
#ifdef GHC_RAISE_UNICODE_ERRORS
            throw filesystem_error(
                "Illegal byte sequence for unicode character.", utf8String,
                std::make_error_code(std::errc::illegal_byte_sequence));
#else
            result += static_cast<typename StringType::value_type>(0xfffd);
            utf8_state = S_STRT;
            codepoint = 0;
#endif
          }
        }
        if (utf8_state) {
#ifdef GHC_RAISE_UNICODE_ERRORS
          throw filesystem_error(
              "Illegal byte sequence for unicode character.", utf8String,
              std::make_error_code(std::errc::illegal_byte_sequence));
#else
          result += static_cast<typename StringType::value_type>(0xfffd);
#endif
        }
        return result;
      }

      template <class StringType, typename std::enable_if<(
                                      sizeof(typename StringType::value_type) ==
                                      4)>::type * = nullptr>
      inline StringType
      fromUtf8(const std::string & utf8String,
               const typename StringType::allocator_type & alloc =
                   typename StringType::allocator_type()) {
        StringType result(alloc);
        result.reserve(utf8String.length());
        std::string::const_iterator iter = utf8String.begin();
        unsigned utf8_state = S_STRT;
        std::uint32_t codepoint = 0;
        while (iter < utf8String.end()) {
          if ((utf8_state = consumeUtf8Fragment(utf8_state,
                                                static_cast<uint8_t>(*iter++),
                                                codepoint)) == S_STRT) {
            result += static_cast<typename StringType::value_type>(codepoint);
            codepoint = 0;
          } else if (utf8_state == S_RJCT) {
#ifdef GHC_RAISE_UNICODE_ERRORS
            throw filesystem_error(
                "Illegal byte sequence for unicode character.", utf8String,
                std::make_error_code(std::errc::illegal_byte_sequence));
#else
            result += static_cast<typename StringType::value_type>(0xfffd);
            utf8_state = S_STRT;
            codepoint = 0;
#endif
          }
        }
        if (utf8_state) {
#ifdef GHC_RAISE_UNICODE_ERRORS
          throw filesystem_error(
              "Illegal byte sequence for unicode character.", utf8String,
              std::make_error_code(std::errc::illegal_byte_sequence));
#else
          result += static_cast<typename StringType::value_type>(0xfffd);
#endif
        }
        return result;
      }

      template <
          typename charT, typename traits, typename Alloc,
          typename std::enable_if<(sizeof(charT) == 1), int>::type size = 1>
      inline std::string
      toUtf8(const std::basic_string<charT, traits, Alloc> & unicodeString) {
        return std::string(unicodeString.begin(), unicodeString.end());
      }

      template <
          typename charT, typename traits, typename Alloc,
          typename std::enable_if<(sizeof(charT) == 2), int>::type size = 2>
      inline std::string
      toUtf8(const std::basic_string<charT, traits, Alloc> & unicodeString) {
        std::string result;
        for (auto iter = unicodeString.begin(); iter != unicodeString.end();
             ++iter) {
          char32_t c = *iter;
          if (is_surrogate(c)) {
            ++iter;
            if (iter != unicodeString.end() && is_high_surrogate(c) &&
                is_low_surrogate(*iter)) {
              appendUTF8(result, (char32_t(c) << 10) + *iter - 0x35fdc00);
            } else {
#ifdef GHC_RAISE_UNICODE_ERRORS
              throw filesystem_error(
                  "Illegal code point for unicode character.", result,
                  std::make_error_code(std::errc::illegal_byte_sequence));
#else
              appendUTF8(result, 0xfffd);
              if (iter == unicodeString.end()) { break; }
#endif
            }
          } else {
            appendUTF8(result, c);
          }
        }
        return result;
      }

      template <
          typename charT, typename traits, typename Alloc,
          typename std::enable_if<(sizeof(charT) == 4), int>::type size = 4>
      inline std::string
      toUtf8(const std::basic_string<charT, traits, Alloc> & unicodeString) {
        std::string result;
        for (auto c : unicodeString) {
          appendUTF8(result, static_cast<uint32_t>(c));
        }
        return result;
      }

      template <typename charT>
      inline std::string toUtf8(const charT * unicodeString) {
        return toUtf8(
            std::basic_string<charT, std::char_traits<charT>>(unicodeString));
      }

    } // namespace detail

#ifdef GHC_EXPAND_IMPL

    namespace detail {

      GHC_INLINE bool startsWith(const std::string & what,
                                 const std::string & with) {
        return with.length() <= what.length() &&
               equal(with.begin(), with.end(), what.begin());
      }

    } // namespace detail

    GHC_INLINE void
    path::postprocess_path_with_format(path::impl_string_type & p,
                                       path::format fmt) {
#ifdef GHC_RAISE_UNICODE_ERRORS
      if (!detail::validUtf8(p)) {
        path t;
        t._path = p;
        throw filesystem_error(
            "Illegal byte sequence for unicode character.", t,
            std::make_error_code(std::errc::illegal_byte_sequence));
      }
#endif
      switch (fmt) {
#ifndef GHC_OS_WINDOWS
      case path::auto_format:
      case path::native_format:
#endif
      case path::generic_format:
        // nothing to do
        break;
#ifdef GHC_OS_WINDOWS
      case path::auto_format:
      case path::native_format:
        if (detail::startsWith(p, std::string("\\\\?\\"))) {
          // remove Windows long filename marker
          p.erase(0, 4);
          if (detail::startsWith(p, std::string("UNC\\"))) {
            p.erase(0, 2);
            p[0] = '\\';
          }
        }
        for (auto & c : p) {
          if (c == '\\') { c = '/'; }
        }
        break;
#endif
      }
      if (p.length() > 2 && p[0] == '/' && p[1] == '/' && p[2] != '/') {
        std::string::iterator new_end =
            std::unique(p.begin() + 2, p.end(),
                        [](path::value_type lhs, path::value_type rhs) {
                          return lhs == rhs && lhs == '/';
                        });
        p.erase(new_end, p.end());
      } else {
        std::string::iterator new_end = std::unique(
            p.begin(), p.end(), [](path::value_type lhs, path::value_type rhs) {
              return lhs == rhs && lhs == '/';
            });
        p.erase(new_end, p.end());
      }
    }

#endif // GHC_EXPAND_IMPL

    template <class Source, typename>
    inline path::path(const Source & source, format fmt)
        : _path(detail::toUtf8(source)) {
      postprocess_path_with_format(_path, fmt);
    }
    template <> inline path::path(const std::wstring & source, format fmt) {
      _path = detail::toUtf8(source);
      postprocess_path_with_format(_path, fmt);
    }
    template <> inline path::path(const std::u16string & source, format fmt) {
      _path = detail::toUtf8(source);
      postprocess_path_with_format(_path, fmt);
    }
    template <> inline path::path(const std::u32string & source, format fmt) {
      _path = detail::toUtf8(source);
      postprocess_path_with_format(_path, fmt);
    }

#ifdef __cpp_lib_string_view
    template <> inline path::path(const std::string_view & source, format fmt) {
      _path = detail::toUtf8(std::string(source));
      postprocess_path_with_format(_path, fmt);
    }
#ifdef GHC_USE_WCHAR_T
    template <>
    inline path::path(const std::wstring_view & source, format fmt) {
      _path = detail::toUtf8(std::wstring(source).c_str());
      postprocess_path_with_format(_path, fmt);
    }
#endif
#endif

    template <class Source, typename>
    inline path u8path(const Source & source) {
      return path(source);
    }
    template <class InputIterator>
    inline path u8path(InputIterator first, InputIterator last) {
      return path(first, last);
    }

    template <class InputIterator>
    inline path::path(InputIterator first, InputIterator last, format fmt)
        : path(std::basic_string<
                   typename std::iterator_traits<InputIterator>::value_type>(
                   first, last),
               fmt) {
      // delegated
    }

#ifdef GHC_EXPAND_IMPL

    namespace detail {

      GHC_INLINE bool equals_simple_insensitive(const char * str1,
                                                const char * str2) {
#ifdef GHC_OS_WINDOWS
#ifdef __GNUC__
        while (::tolower((unsigned char)*str1) ==
               ::tolower((unsigned char)*str2++)) {
          if (*str1++ == 0) return true;
        }
        return false;
#else
        return 0 == ::_stricmp(str1, str2);
#endif
#else
        return 0 == ::strcasecmp(str1, str2);
#endif
      }

      GHC_INLINE const char * strerror_adapter(char * gnu, char *) {
        return gnu;
      }

      GHC_INLINE const char * strerror_adapter(int posix, char * buffer) {
        if (posix) { return "Error in strerror_r!"; }
        return buffer;
      }

      template <typename ErrorNumber>
      GHC_INLINE std::string systemErrorText(ErrorNumber code = 0) {
#if defined(GHC_OS_WINDOWS)
        LPVOID msgBuf;
        DWORD dw = code ? static_cast<DWORD>(code) : ::GetLastError();
        FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                           FORMAT_MESSAGE_FROM_SYSTEM |
                           FORMAT_MESSAGE_IGNORE_INSERTS,
                       NULL, dw, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                       (LPWSTR)&msgBuf, 0, NULL);
        std::string msg = toUtf8(std::wstring((LPWSTR)msgBuf));
        LocalFree(msgBuf);
        return msg;
#else
        char buffer[512];
        return strerror_adapter(
            strerror_r(code ? code : errno, buffer, sizeof(buffer)), buffer);
#endif
      }

#ifdef GHC_OS_WINDOWS
      using CreateSymbolicLinkW_fp = BOOLEAN(WINAPI *)(LPCWSTR, LPCWSTR, DWORD);
      using CreateHardLinkW_fp = BOOLEAN(WINAPI *)(LPCWSTR, LPCWSTR,
                                                   LPSECURITY_ATTRIBUTES);

      GHC_INLINE void create_symlink(const path & target_name,
                                     const path & new_symlink,
                                     bool to_directory, std::error_code & ec) {
        std::error_code tec;
        auto fs = status(target_name, tec);
        if ((fs.type() == file_type::directory && !to_directory) ||
            (fs.type() == file_type::regular && to_directory)) {
          ec = detail::make_error_code(detail::portable_error::not_supported);
          return;
        }
#if defined(__GNUC__) && __GNUC__ >= 8
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-function-type"
#endif
        static CreateSymbolicLinkW_fp api_call =
            reinterpret_cast<CreateSymbolicLinkW_fp>(GetProcAddress(
                GetModuleHandleW(L"kernel32.dll"), "CreateSymbolicLinkW"));
#if defined(__GNUC__) && __GNUC__ >= 8
#pragma GCC diagnostic pop
#endif
        if (api_call) {
          if (api_call(detail::fromUtf8<std::wstring>(new_symlink.u8string())
                           .c_str(),
                       detail::fromUtf8<std::wstring>(target_name.u8string())
                           .c_str(),
                       to_directory ? 1 : 0) == 0) {
            auto result = ::GetLastError();
            if (result == ERROR_PRIVILEGE_NOT_HELD &&
                api_call(detail::fromUtf8<std::wstring>(new_symlink.u8string())
                             .c_str(),
                         detail::fromUtf8<std::wstring>(target_name.u8string())
                             .c_str(),
                         to_directory ? 3 : 2) != 0) {
              return;
            }
            ec = detail::make_system_error(result);
          }
        } else {
          ec = detail::make_system_error(ERROR_NOT_SUPPORTED);
        }
      }

      GHC_INLINE void create_hardlink(const path & target_name,
                                      const path & new_hardlink,
                                      std::error_code & ec) {
#if defined(__GNUC__) && __GNUC__ >= 8
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-function-type"
#endif
        static CreateHardLinkW_fp api_call =
            reinterpret_cast<CreateHardLinkW_fp>(GetProcAddress(
                GetModuleHandleW(L"kernel32.dll"), "CreateHardLinkW"));
#if defined(__GNUC__) && __GNUC__ >= 8
#pragma GCC diagnostic pop
#endif
        if (api_call) {
          if (api_call(detail::fromUtf8<std::wstring>(new_hardlink.u8string())
                           .c_str(),
                       detail::fromUtf8<std::wstring>(target_name.u8string())
                           .c_str(),
                       NULL) == 0) {
            ec = detail::make_system_error();
          }
        } else {
          ec = detail::make_system_error(ERROR_NOT_SUPPORTED);
        }
      }
#else
      GHC_INLINE void create_symlink(const path & target_name,
                                     const path & new_symlink, bool,
                                     std::error_code & ec) {
        if (::symlink(target_name.c_str(), new_symlink.c_str()) != 0) {
          ec = detail::make_system_error();
        }
      }

#ifndef GHC_OS_WEB
      GHC_INLINE void create_hardlink(const path & target_name,
                                      const path & new_hardlink,
                                      std::error_code & ec) {
        if (::link(target_name.c_str(), new_hardlink.c_str()) != 0) {
          ec = detail::make_system_error();
        }
      }
#endif
#endif

      template <typename T>
      GHC_INLINE file_status file_status_from_st_mode(T mode) {
#ifdef GHC_OS_WINDOWS
        file_type ft = file_type::unknown;
        if ((mode & _S_IFDIR) == _S_IFDIR) {
          ft = file_type::directory;
        } else if ((mode & _S_IFREG) == _S_IFREG) {
          ft = file_type::regular;
        } else if ((mode & _S_IFCHR) == _S_IFCHR) {
          ft = file_type::character;
        }
        perms prms = static_cast<perms>(mode & 0xfff);
        return file_status(ft, prms);
#else
        file_type ft = file_type::unknown;
        if (S_ISDIR(mode)) {
          ft = file_type::directory;
        } else if (S_ISREG(mode)) {
          ft = file_type::regular;
        } else if (S_ISCHR(mode)) {
          ft = file_type::character;
        } else if (S_ISBLK(mode)) {
          ft = file_type::block;
        } else if (S_ISFIFO(mode)) {
          ft = file_type::fifo;
        } else if (S_ISLNK(mode)) {
          ft = file_type::symlink;
        } else if (S_ISSOCK(mode)) {
          ft = file_type::socket;
        }
        perms prms = static_cast<perms>(mode & 0xfff);
        return file_status(ft, prms);
#endif
      }

      GHC_INLINE path resolveSymlink(const path & p, std::error_code & ec) {
#ifdef GHC_OS_WINDOWS
#ifndef REPARSE_DATA_BUFFER_HEADER_SIZE
        typedef struct _REPARSE_DATA_BUFFER {
          ULONG ReparseTag;
          USHORT ReparseDataLength;
          USHORT Reserved;
          union {
            struct {
              USHORT SubstituteNameOffset;
              USHORT SubstituteNameLength;
              USHORT PrintNameOffset;
              USHORT PrintNameLength;
              ULONG Flags;
              WCHAR PathBuffer[1];
            } SymbolicLinkReparseBuffer;
            struct {
              USHORT SubstituteNameOffset;
              USHORT SubstituteNameLength;
              USHORT PrintNameOffset;
              USHORT PrintNameLength;
              WCHAR PathBuffer[1];
            } MountPointReparseBuffer;
            struct {
              UCHAR DataBuffer[1];
            } GenericReparseBuffer;
          } DUMMYUNIONNAME;
        } REPARSE_DATA_BUFFER;
#ifndef MAXIMUM_REPARSE_DATA_BUFFER_SIZE
#define MAXIMUM_REPARSE_DATA_BUFFER_SIZE (16 * 1024)
#endif
#endif

        std::shared_ptr<void> file(
            CreateFileW(
                p.wstring().c_str(), 0,
                FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, 0,
                OPEN_EXISTING,
                FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS, 0),
            CloseHandle);
        if (file.get() == INVALID_HANDLE_VALUE) {
          ec = detail::make_system_error();
          return path();
        }

        std::shared_ptr<REPARSE_DATA_BUFFER> reparseData(
            (REPARSE_DATA_BUFFER *)std::calloc(
                1, MAXIMUM_REPARSE_DATA_BUFFER_SIZE),
            std::free);
        ULONG bufferUsed;
        path result;
        if (DeviceIoControl(file.get(), FSCTL_GET_REPARSE_POINT, 0, 0,
                            reparseData.get(), MAXIMUM_REPARSE_DATA_BUFFER_SIZE,
                            &bufferUsed, 0)) {
          if (IsReparseTagMicrosoft(reparseData->ReparseTag)) {
            switch (reparseData->ReparseTag) {
            case IO_REPARSE_TAG_SYMLINK:
              result = std::wstring(
                  &reparseData->SymbolicLinkReparseBuffer.PathBuffer
                       [reparseData->SymbolicLinkReparseBuffer.PrintNameOffset /
                        sizeof(WCHAR)],
                  reparseData->SymbolicLinkReparseBuffer.PrintNameLength /
                      sizeof(WCHAR));
              break;
            case IO_REPARSE_TAG_MOUNT_POINT:
              result = std::wstring(
                  &reparseData->MountPointReparseBuffer.PathBuffer
                       [reparseData->MountPointReparseBuffer.PrintNameOffset /
                        sizeof(WCHAR)],
                  reparseData->MountPointReparseBuffer.PrintNameLength /
                      sizeof(WCHAR));
              break;
            default:
              break;
            }
          }
        } else {
          ec = detail::make_system_error();
        }
        return result;
#else
        size_t bufferSize = 256;
        while (true) {
          std::vector<char> buffer(bufferSize, static_cast<char>(0));
          auto rc = ::readlink(p.c_str(), buffer.data(), buffer.size());
          if (rc < 0) {
            ec = detail::make_system_error();
            return path();
          } else if (rc < static_cast<int>(bufferSize)) {
            return path(std::string(buffer.data(),
                                    static_cast<std::string::size_type>(rc)));
          }
          bufferSize *= 2;
        }
        return path();
#endif
      }

#ifdef GHC_OS_WINDOWS
      GHC_INLINE time_t timeFromFILETIME(const FILETIME & ft) {
        ULARGE_INTEGER ull;
        ull.LowPart = ft.dwLowDateTime;
        ull.HighPart = ft.dwHighDateTime;
        return static_cast<time_t>(ull.QuadPart / 10000000ULL - 11644473600ULL);
      }

      GHC_INLINE void timeToFILETIME(time_t t, FILETIME & ft) {
        LONGLONG ll;
        ll = Int32x32To64(t, 10000000) + 116444736000000000;
        ft.dwLowDateTime = static_cast<DWORD>(ll);
        ft.dwHighDateTime = static_cast<DWORD>(ll >> 32);
      }

      template <typename INFO>
      GHC_INLINE uintmax_t hard_links_from_INFO(const INFO * info) {
        return static_cast<uintmax_t>(-1);
      }

      template <>
      GHC_INLINE uintmax_t hard_links_from_INFO<BY_HANDLE_FILE_INFORMATION>(
          const BY_HANDLE_FILE_INFORMATION * info) {
        return info->nNumberOfLinks;
      }

      template <typename INFO>
      GHC_INLINE file_status status_from_INFO(const path & p, const INFO * info,
                                              std::error_code &,
                                              uintmax_t * sz = nullptr,
                                              time_t * lwt = nullptr) noexcept {
        file_type ft = file_type::unknown;
        if ((info->dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
          ft = file_type::symlink;
        } else {
          if ((info->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) {
            ft = file_type::directory;
          } else {
            ft = file_type::regular;
          }
        }
        perms prms = perms::owner_read | perms::group_read | perms::others_read;
        if (!(info->dwFileAttributes & FILE_ATTRIBUTE_READONLY)) {
          prms = prms | perms::owner_write | perms::group_write |
                 perms::others_write;
        }
        std::string ext = p.extension().generic_string();
        if (equals_simple_insensitive(ext.c_str(), ".exe") ||
            equals_simple_insensitive(ext.c_str(), ".cmd") ||
            equals_simple_insensitive(ext.c_str(), ".bat") ||
            equals_simple_insensitive(ext.c_str(), ".com")) {
          prms =
              prms | perms::owner_exec | perms::group_exec | perms::others_exec;
        }
        if (sz) {
          *sz = static_cast<uintmax_t>(info->nFileSizeHigh)
                    << (sizeof(info->nFileSizeHigh) * 8) |
                info->nFileSizeLow;
        }
        if (lwt) { *lwt = detail::timeFromFILETIME(info->ftLastWriteTime); }
        return file_status(ft, prms);
      }

#endif

      GHC_INLINE bool is_not_found_error(std::error_code & ec) {
#ifdef GHC_OS_WINDOWS
        return ec.value() == ERROR_FILE_NOT_FOUND ||
               ec.value() == ERROR_PATH_NOT_FOUND ||
               ec.value() == ERROR_INVALID_NAME;
#else
        return ec.value() == ENOENT || ec.value() == ENOTDIR;
#endif
      }

      GHC_INLINE file_status symlink_status_ex(
          const path & p, std::error_code & ec, uintmax_t * sz = nullptr,
          uintmax_t * nhl = nullptr, time_t * lwt = nullptr) noexcept {
#ifdef GHC_OS_WINDOWS
        file_status fs;
        WIN32_FILE_ATTRIBUTE_DATA attr;
        if (!GetFileAttributesExW(
                detail::fromUtf8<std::wstring>(p.u8string()).c_str(),
                GetFileExInfoStandard, &attr)) {
          ec = detail::make_system_error();
        } else {
          ec.clear();
          fs = detail::status_from_INFO(p, &attr, ec, sz, lwt);
          if (nhl) { *nhl = 0; }
          if (attr.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
            fs.type(file_type::symlink);
          }
        }
        if (detail::is_not_found_error(ec)) {
          return file_status(file_type::not_found);
        }
        return ec ? file_status(file_type::none) : fs;
#else
        (void)sz;
        (void)nhl;
        (void)lwt;
        struct ::stat fs;
        auto result = ::lstat(p.c_str(), &fs);
        if (result == 0) {
          ec.clear();
          file_status f_s = detail::file_status_from_st_mode(fs.st_mode);
          return f_s;
        }
        ec = detail::make_system_error();
        if (detail::is_not_found_error(ec)) {
          return file_status(file_type::not_found, perms::unknown);
        }
        return file_status(file_type::none);
#endif
      }

      GHC_INLINE file_status status_ex(const path & p, std::error_code & ec,
                                       file_status * sls = nullptr,
                                       uintmax_t * sz = nullptr,
                                       uintmax_t * nhl = nullptr,
                                       time_t * lwt = nullptr,
                                       int recurse_count = 0) noexcept {
        ec.clear();
#ifdef GHC_OS_WINDOWS
        if (recurse_count > 16) {
          ec = detail::make_system_error(0x2A9 /*ERROR_STOPPED_ON_SYMLINK*/);
          return file_status(file_type::unknown);
        }
        WIN32_FILE_ATTRIBUTE_DATA attr;
        if (!::GetFileAttributesExW(p.wstring().c_str(), GetFileExInfoStandard,
                                    &attr)) {
          ec = detail::make_system_error();
        } else if (attr.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
          path target = resolveSymlink(p, ec);
          file_status result;
          if (!ec && !target.empty()) {
            if (sls) { *sls = status_from_INFO(p, &attr, ec); }
            return detail::status_ex(target, ec, nullptr, sz, nhl, lwt,
                                     recurse_count + 1);
          }
          return file_status(file_type::unknown);
        }
        if (ec) {
          if (detail::is_not_found_error(ec)) {
            return file_status(file_type::not_found);
          }
          return file_status(file_type::none);
        }
        if (nhl) { *nhl = 0; }
        return detail::status_from_INFO(p, &attr, ec, sz, lwt);
#else
        (void)recurse_count;
        struct ::stat st;
        auto result = ::lstat(p.c_str(), &st);
        if (result == 0) {
          ec.clear();
          file_status fs = detail::file_status_from_st_mode(st.st_mode);
          if (fs.type() == file_type::symlink) {
            result = ::stat(p.c_str(), &st);
            if (result == 0) {
              if (sls) { *sls = fs; }
              fs = detail::file_status_from_st_mode(st.st_mode);
            }
          }
          if (sz) { *sz = static_cast<uintmax_t>(st.st_size); }
          if (nhl) { *nhl = st.st_nlink; }
          if (lwt) { *lwt = st.st_mtime; }
          return fs;
        } else {
          ec = detail::make_system_error();
          if (detail::is_not_found_error(ec)) {
            return file_status(file_type::not_found, perms::unknown);
          }
          return file_status(file_type::none);
        }
#endif
      }

    } // namespace detail

    GHC_INLINE u8arguments::u8arguments(int & argc, char **& argv)
        : _argc(argc), _argv(argv), _refargc(argc), _refargv(argv),
          _isvalid(false) {
#ifdef GHC_OS_WINDOWS
      LPWSTR * p;
      p = ::CommandLineToArgvW(::GetCommandLineW(), &argc);
      _args.reserve(static_cast<size_t>(argc));
      _argp.reserve(static_cast<size_t>(argc));
      for (size_t i = 0; i < static_cast<size_t>(argc); ++i) {
        _args.push_back(detail::toUtf8(std::wstring(p[i])));
        _argp.push_back((char *)_args[i].data());
      }
      argv = _argp.data();
      ::LocalFree(p);
      _isvalid = true;
#else
      std::setlocale(LC_ALL, "");
#if defined(__ANDROID__) && __ANDROID_API__ < 26
      _isvalid = true;
#else
      if (detail::equals_simple_insensitive(::nl_langinfo(CODESET), "UTF-8")) {
        _isvalid = true;
      }
#endif
#endif
    }

    //-----------------------------------------------------------------------------
    // 30.10.8.4.1 constructors and destructor

    GHC_INLINE path::path() noexcept {}

    GHC_INLINE path::path(const path & p) : _path(p._path) {}

    GHC_INLINE path::path(path && p) noexcept : _path(std::move(p._path)) {}

    GHC_INLINE path::path(string_type && source, format fmt)
#ifdef GHC_USE_WCHAR_T
        : _path(detail::toUtf8(source))
#else
        : _path(std::move(source))
#endif
    {
      postprocess_path_with_format(_path, fmt);
    }

#endif // GHC_EXPAND_IMPL

#ifdef GHC_WITH_EXCEPTIONS
    template <class Source, typename>
    inline path::path(const Source & source, const std::locale & loc,
                      format fmt)
        : path(source, fmt) {
      std::string locName = loc.name();
      if (!(locName.length() >= 5 &&
            (locName.substr(locName.length() - 5) == "UTF-8" ||
             locName.substr(locName.length() - 5) == "utf-8"))) {
        throw filesystem_error(
            "This implementation only supports UTF-8 locales!", path(_path),
            detail::make_error_code(detail::portable_error::not_supported));
      }
    }

    template <class InputIterator>
    inline path::path(InputIterator first, InputIterator last,
                      const std::locale & loc, format fmt)
        : path(std::basic_string<
                   typename std::iterator_traits<InputIterator>::value_type>(
                   first, last),
               fmt) {
      std::string locName = loc.name();
      if (!(locName.length() >= 5 &&
            (locName.substr(locName.length() - 5) == "UTF-8" ||
             locName.substr(locName.length() - 5) == "utf-8"))) {
        throw filesystem_error(
            "This implementation only supports UTF-8 locales!", path(_path),
            detail::make_error_code(detail::portable_error::not_supported));
      }
    }
#endif

#ifdef GHC_EXPAND_IMPL

    GHC_INLINE path::~path() {}

    //-----------------------------------------------------------------------------
    // 30.10.8.4.2 assignments

    GHC_INLINE path & path::operator=(const path & p) {
      _path = p._path;
      return *this;
    }

    GHC_INLINE path & path::operator=(path && p) noexcept {
      _path = std::move(p._path);
      return *this;
    }

    GHC_INLINE path & path::operator=(path::string_type && source) {
      return assign(source);
    }

    GHC_INLINE path & path::assign(path::string_type && source) {
#ifdef GHC_USE_WCHAR_T
      _path = detail::toUtf8(source);
#else
      _path = std::move(source);
#endif
      postprocess_path_with_format(_path, native_format);
      return *this;
    }

#endif // GHC_EXPAND_IMPL

    template <class Source>
    inline path & path::operator=(const Source & source) {
      return assign(source);
    }

    template <class Source> inline path & path::assign(const Source & source) {
      _path.assign(detail::toUtf8(source));
      postprocess_path_with_format(_path, native_format);
      return *this;
    }

    template <> inline path & path::assign<path>(const path & source) {
      _path = source._path;
      return *this;
    }

    template <class InputIterator>
    inline path & path::assign(InputIterator first, InputIterator last) {
      _path.assign(first, last);
      postprocess_path_with_format(_path, native_format);
      return *this;
    }

#ifdef GHC_EXPAND_IMPL

    //-----------------------------------------------------------------------------
    // 30.10.8.4.3 appends

    GHC_INLINE path & path::operator/=(const path & p) {
      if (p.empty()) {
        // was: if ((!has_root_directory() && is_absolute()) || has_filename())
        if (!_path.empty() && _path[_path.length() - 1] != '/' &&
            _path[_path.length() - 1] != ':') {
          _path += '/';
        }
        return *this;
      }
      if ((p.is_absolute() && (_path != root_name() || p._path != "/")) ||
          (p.has_root_name() && p.root_name() != root_name())) {
        assign(p);
        return *this;
      }
      if (p.has_root_directory()) {
        assign(root_name());
      } else if ((!has_root_directory() && is_absolute()) || has_filename()) {
        _path += '/';
      }
      auto iter = p.begin();
      bool first = true;
      if (p.has_root_name()) { ++iter; }
      while (iter != p.end()) {
        if (!first && !(!_path.empty() && _path[_path.length() - 1] == '/')) {
          _path += '/';
        }
        first = false;
        _path += (*iter++).generic_string();
      }
      return *this;
    }

    GHC_INLINE void path::append_name(const char * name) {
      if (_path.empty()) {
        this->operator/=(path(name));
      } else {
        if (_path.back() != path::generic_separator) {
          _path.push_back(path::generic_separator);
        }
        _path += name;
      }
    }

#endif // GHC_EXPAND_IMPL

    template <class Source>
    inline path & path::operator/=(const Source & source) {
      return append(source);
    }

    template <class Source> inline path & path::append(const Source & source) {
      return this->operator/=(path(detail::toUtf8(source)));
    }

    template <> inline path & path::append<path>(const path & p) {
      return this->operator/=(p);
    }

    template <class InputIterator>
    inline path & path::append(InputIterator first, InputIterator last) {
      std::basic_string<
          typename std::iterator_traits<InputIterator>::value_type>
          part(first, last);
      return append(part);
    }

#ifdef GHC_EXPAND_IMPL

    //-----------------------------------------------------------------------------
    // 30.10.8.4.4 concatenation

    GHC_INLINE path & path::operator+=(const path & x) {
      return concat(x._path);
    }

    GHC_INLINE path & path::operator+=(const string_type & x) {
      return concat(x);
    }

#ifdef __cpp_lib_string_view
    GHC_INLINE path & path::operator+=(std::basic_string_view<value_type> x) {
      return concat(x);
    }
#endif

    GHC_INLINE path & path::operator+=(const value_type * x) {
      return concat(string_type(x));
    }

    GHC_INLINE path & path::operator+=(value_type x) {
#ifdef GHC_OS_WINDOWS
      if (x == '\\') { x = generic_separator; }
#endif
      if (_path.empty() || _path.back() != generic_separator) {
#ifdef GHC_USE_WCHAR_T
        _path += detail::toUtf8(string_type(1, x));
#else
        _path += x;
#endif
      }
      return *this;
    }

#endif // GHC_EXPAND_IMPL

    template <class Source>
    inline path::path_from_string<Source> & path::operator+=(const Source & x) {
      return concat(x);
    }

    template <class EcharT>
    inline path::path_type_EcharT<EcharT> & path::operator+=(EcharT x) {
      std::basic_string<EcharT> part(1, x);
      concat(detail::toUtf8(part));
      return *this;
    }

    template <class Source> inline path & path::concat(const Source & x) {
      path p(x);
      postprocess_path_with_format(p._path, native_format);
      _path += p._path;
      return *this;
    }
    template <class InputIterator>
    inline path & path::concat(InputIterator first, InputIterator last) {
      _path.append(first, last);
      postprocess_path_with_format(_path, native_format);
      return *this;
    }

#ifdef GHC_EXPAND_IMPL

    //-----------------------------------------------------------------------------
    // 30.10.8.4.5 modifiers
    GHC_INLINE void path::clear() noexcept { _path.clear(); }

    GHC_INLINE path & path::make_preferred() {
      // as this filesystem implementation only uses generic_format
      // internally, this must be a no-op
      return *this;
    }

    GHC_INLINE path & path::remove_filename() {
      if (has_filename()) {
        _path.erase(_path.size() - filename()._path.size());
      }
      return *this;
    }

    GHC_INLINE path & path::replace_filename(const path & replacement) {
      remove_filename();
      return append(replacement);
    }

    GHC_INLINE path & path::replace_extension(const path & replacement) {
      if (has_extension()) {
        _path.erase(_path.size() - extension()._path.size());
      }
      if (!replacement.empty() && replacement._path[0] != '.') { _path += '.'; }
      return concat(replacement);
    }

    GHC_INLINE void path::swap(path & rhs) noexcept { _path.swap(rhs._path); }

//-----------------------------------------------------------------------------
// 30.10.8.4.6, native format observers
#ifdef GHC_OS_WINDOWS
    GHC_INLINE path::impl_string_type path::native_impl() const {
      impl_string_type result;
      if (is_absolute() && _path.length() > MAX_PATH - 10) {
        // expand long Windows filenames with marker
        if (has_root_name() && _path[0] == '/') {
          result = "\\\\?\\UNC" + _path.substr(1);
        } else {
          result = "\\\\?\\" + _path;
        }
      } else {
        result = _path;
      }
      /*if (has_root_name() && root_name()._path[0] == '/') {
          return _path;
      }*/
      for (auto & c : result) {
        if (c == '/') { c = '\\'; }
      }
      return result;
    }
#else
    GHC_INLINE const path::impl_string_type & path::native_impl() const {
      return _path;
    }
#endif

    GHC_INLINE const path::string_type & path::native() const {
#ifdef GHC_OS_WINDOWS
#ifdef GHC_USE_WCHAR_T
      _native_cache = detail::fromUtf8<string_type>(native_impl());
#else
      _native_cache = native_impl();
#endif
      return _native_cache;
#else
      return _path;
#endif
    }

    GHC_INLINE const path::value_type * path::c_str() const {
      return native().c_str();
    }

    GHC_INLINE path::operator path::string_type() const { return native(); }

#endif // GHC_EXPAND_IMPL

    template <class EcharT, class traits, class Allocator>
    inline std::basic_string<EcharT, traits, Allocator>
    path::string(const Allocator & a) const {
      return detail::fromUtf8<std::basic_string<EcharT, traits, Allocator>>(
          native_impl(), a);
    }

#ifdef GHC_EXPAND_IMPL

    GHC_INLINE std::string path::string() const { return native_impl(); }

    GHC_INLINE std::wstring path::wstring() const {
#ifdef GHC_USE_WCHAR_T
      return native();
#else
      return detail::fromUtf8<std::wstring>(native());
#endif
    }

    GHC_INLINE std::string path::u8string() const { return native_impl(); }

    GHC_INLINE std::u16string path::u16string() const {
      return detail::fromUtf8<std::u16string>(native_impl());
    }

    GHC_INLINE std::u32string path::u32string() const {
      return detail::fromUtf8<std::u32string>(native_impl());
    }

#endif // GHC_EXPAND_IMPL

    //-----------------------------------------------------------------------------
    // 30.10.8.4.7, generic format observers
    template <class EcharT, class traits, class Allocator>
    inline std::basic_string<EcharT, traits, Allocator>
    path::generic_string(const Allocator & a) const {
      return detail::fromUtf8<std::basic_string<EcharT, traits, Allocator>>(
          _path, a);
    }

#ifdef GHC_EXPAND_IMPL

    GHC_INLINE const std::string & path::generic_string() const {
      return _path;
    }

    GHC_INLINE std::wstring path::generic_wstring() const {
      return detail::fromUtf8<std::wstring>(_path);
    }

    GHC_INLINE std::string path::generic_u8string() const { return _path; }

    GHC_INLINE std::u16string path::generic_u16string() const {
      return detail::fromUtf8<std::u16string>(_path);
    }

    GHC_INLINE std::u32string path::generic_u32string() const {
      return detail::fromUtf8<std::u32string>(_path);
    }

    //-----------------------------------------------------------------------------
    // 30.10.8.4.8, compare
    GHC_INLINE int path::compare(const path & p) const noexcept {
      return native().compare(p.native());
    }

    GHC_INLINE int path::compare(const string_type & s) const {
      return native().compare(path(s).native());
    }

#ifdef __cpp_lib_string_view
    GHC_INLINE int path::compare(std::basic_string_view<value_type> s) const {
      return native().compare(path(s).native());
    }
#endif

    GHC_INLINE int path::compare(const value_type * s) const {
      return native().compare(path(s).native());
    }

    //-----------------------------------------------------------------------------
    // 30.10.8.4.9, decomposition
    GHC_INLINE path path::root_name() const {
#ifdef GHC_OS_WINDOWS
      if (_path.length() >= 2 &&
          std::toupper(static_cast<unsigned char>(_path[0])) >= 'A' &&
          std::toupper(static_cast<unsigned char>(_path[0])) <= 'Z' &&
          _path[1] == ':') {
        return path(_path.substr(0, 2));
      }
#endif
      if (_path.length() > 2 && _path[0] == '/' && _path[1] == '/' &&
          _path[2] != '/' && std::isprint(_path[2])) {
        impl_string_type::size_type pos = _path.find_first_of("/\\", 3);
        if (pos == impl_string_type::npos) {
          return path(_path);
        } else {
          return path(_path.substr(0, pos));
        }
      }
      return path();
    }

    GHC_INLINE path path::root_directory() const {
      path root = root_name();
      if (_path.length() > root._path.length() &&
          _path[root._path.length()] == '/') {
        return path("/");
      }
      return path();
    }

    GHC_INLINE path path::root_path() const {
      return root_name().generic_string() + root_directory().generic_string();
    }

    GHC_INLINE path path::relative_path() const {
      std::string root = root_path()._path;
      return path(_path.substr((std::min)(root.length(), _path.length())),
                  generic_format);
    }

    GHC_INLINE path path::parent_path() const {
      if (has_relative_path()) {
        if (empty() || begin() == --end()) {
          return path();
        } else {
          path pp;
          for (string_type s :
               input_iterator_range<iterator>(begin(), --end())) {
            if (s == "/") {
              // don't use append to join a path-
              pp += s;
            } else {
              pp /= s;
            }
          }
          return pp;
        }
      } else {
        return *this;
      }
    }

    GHC_INLINE path path::filename() const {
      return relative_path().empty() ? path() : path(*--end());
    }

    GHC_INLINE path path::stem() const {
      impl_string_type fn = filename().string();
      if (fn != "." && fn != "..") {
        impl_string_type::size_type n = fn.rfind('.');
        if (n != impl_string_type::npos && n != 0) {
          return path{fn.substr(0, n)};
        }
      }
      return path{fn};
    }

    GHC_INLINE path path::extension() const {
      impl_string_type fn = filename().string();
      impl_string_type::size_type pos = fn.find_last_of('.');
      if (pos == std::string::npos || pos == 0) { return ""; }
      return fn.substr(pos);
    }

    //-----------------------------------------------------------------------------
    // 30.10.8.4.10, query
    GHC_INLINE bool path::empty() const noexcept { return _path.empty(); }

    GHC_INLINE bool path::has_root_name() const { return !root_name().empty(); }

    GHC_INLINE bool path::has_root_directory() const {
      return !root_directory().empty();
    }

    GHC_INLINE bool path::has_root_path() const { return !root_path().empty(); }

    GHC_INLINE bool path::has_relative_path() const {
      return !relative_path().empty();
    }

    GHC_INLINE bool path::has_parent_path() const {
      return !parent_path().empty();
    }

    GHC_INLINE bool path::has_filename() const { return !filename().empty(); }

    GHC_INLINE bool path::has_stem() const { return !stem().empty(); }

    GHC_INLINE bool path::has_extension() const { return !extension().empty(); }

    GHC_INLINE bool path::is_absolute() const {
#ifdef GHC_OS_WINDOWS
      return has_root_name() && has_root_directory();
#else
      return has_root_directory();
#endif
    }

    GHC_INLINE bool path::is_relative() const { return !is_absolute(); }

    //-----------------------------------------------------------------------------
    // 30.10.8.4.11, generation
    GHC_INLINE path path::lexically_normal() const {
      path dest;
      bool lastDotDot = false;
      for (string_type s : *this) {
        if (s == ".") {
          dest /= "";
          continue;
        } else if (s == ".." && !dest.empty()) {
          auto root = root_path();
          if (dest == root) {
            continue;
          } else if (*(--dest.end()) != "..") {
            if (dest._path.back() == generic_separator) {
              dest._path.pop_back();
            }
            dest.remove_filename();
            continue;
          }
        }
        if (!(s.empty() && lastDotDot)) { dest /= s; }
        lastDotDot = s == "..";
      }
      if (dest.empty()) { dest = "."; }
      return dest;
    }

    GHC_INLINE path path::lexically_relative(const path & base) const {
      if (root_name() != base.root_name() ||
          is_absolute() != base.is_absolute() ||
          (!has_root_directory() && base.has_root_directory())) {
        return path();
      }
      const_iterator a = begin(), b = base.begin();
      while (a != end() && b != base.end() && *a == *b) {
        ++a;
        ++b;
      }
      if (a == end() && b == base.end()) { return path("."); }
      int count = 0;
      for (const auto & element :
           input_iterator_range<const_iterator>(b, base.end())) {
        if (element != "." && element != "" && element != "..") {
          ++count;
        } else if (element == "..") {
          --count;
        }
      }
      if (count < 0) { return path(); }
      path result;
      for (int i = 0; i < count; ++i) {
        result /= "..";
      }
      for (const auto & element :
           input_iterator_range<const_iterator>(a, end())) {
        result /= element;
      }
      return result;
    }

    GHC_INLINE path path::lexically_proximate(const path & base) const {
      path result = lexically_relative(base);
      return result.empty() ? *this : result;
    }

    //-----------------------------------------------------------------------------
    // 30.10.8.5, iterators
    GHC_INLINE path::iterator::iterator() {}

    GHC_INLINE path::iterator::iterator(
        const path::impl_string_type::const_iterator & first,
        const path::impl_string_type::const_iterator & last,
        const path::impl_string_type::const_iterator & pos)
        : _first(first), _last(last), _iter(pos) {
      updateCurrent();
      // find the position of a potential root directory slash
#ifdef GHC_OS_WINDOWS
      if (_last - _first >= 3 &&
          std::toupper(static_cast<unsigned char>(*first)) >= 'A' &&
          std::toupper(static_cast<unsigned char>(*first)) <= 'Z' &&
          *(first + 1) == ':' && *(first + 2) == '/') {
        _root = _first + 2;
      } else
#endif
      {
        if (_first != _last && *_first == '/') {
          if (_last - _first >= 2 && *(_first + 1) == '/' &&
              !(_last - _first >= 3 && *(_first + 2) == '/')) {
            _root = increment(_first);
          } else {
            _root = _first;
          }
        } else {
          _root = _last;
        }
      }
    }

    GHC_INLINE path::impl_string_type::const_iterator path::iterator::increment(
        const path::impl_string_type::const_iterator & pos) const {
      path::impl_string_type::const_iterator i = pos;
      bool fromStart = i == _first;
      if (i != _last) {
        // we can only sit on a slash if it is a network name or a root
        if (*i++ == '/') {
          if (i != _last && *i == '/') {
            if (fromStart && !(i + 1 != _last && *(i + 1) == '/')) {
              // leadind double slashes detected, treat this and the
              // following until a slash as one unit
              i = std::find(++i, _last, '/');
            } else {
              // skip redundant slashes
              while (i != _last && *i == '/') {
                ++i;
              }
            }
          }
        } else {
          if (fromStart && i != _last && *i == ':') {
            ++i;
          } else {
            i = std::find(i, _last, '/');
          }
        }
      }
      return i;
    }

    GHC_INLINE path::impl_string_type::const_iterator path::iterator::decrement(
        const path::impl_string_type::const_iterator & pos) const {
      path::impl_string_type::const_iterator i = pos;
      if (i != _first) {
        --i;
        // if this is now the root slash or the trailing slash, we are done,
        // else check for network name
        if (i != _root && (pos != _last || *i != '/')) {
#ifdef GHC_OS_WINDOWS
          static const std::string seps = "/:";
          i = std::find_first_of(
                  std::reverse_iterator<path::impl_string_type::const_iterator>(
                      i),
                  std::reverse_iterator<path::impl_string_type::const_iterator>(
                      _first),
                  seps.begin(), seps.end())
                  .base();
          if (i > _first && *i == ':') { i++; }
#else
          i = std::find(
                  std::reverse_iterator<path::impl_string_type::const_iterator>(
                      i),
                  std::reverse_iterator<path::impl_string_type::const_iterator>(
                      _first),
                  '/')
                  .base();
#endif
          // Now we have to check if this is a network name
          if (i - _first == 2 && *_first == '/' && *(_first + 1) == '/') {
            i -= 2;
          }
        }
      }
      return i;
    }

    GHC_INLINE void path::iterator::updateCurrent() {
      if (_iter != _first && _iter != _last &&
          (*_iter == '/' && _iter != _root) && (_iter + 1 == _last)) {
        _current = "";
      } else {
        _current.assign(_iter, increment(_iter));
        if (_current.generic_string().size() > 1 &&
            _current.generic_string()[0] == '/' &&
            _current.generic_string()[_current.generic_string().size() - 1] ==
                '/') {
          // shrink successive slashes to one
          _current = "/";
        }
      }
    }

    GHC_INLINE path::iterator & path::iterator::operator++() {
      _iter = increment(_iter);
      while (_iter != _last &&    // we didn't reach the end
             _iter != _root &&    // this is not a root position
             *_iter == '/' &&     // we are on a slash
             (_iter + 1) != _last // the slash is not the last char
      ) {
        ++_iter;
      }
      updateCurrent();
      return *this;
    }

    GHC_INLINE path::iterator path::iterator::operator++(int) {
      path::iterator i{*this};
      ++(*this);
      return i;
    }

    GHC_INLINE path::iterator & path::iterator::operator--() {
      _iter = decrement(_iter);
      updateCurrent();
      return *this;
    }

    GHC_INLINE path::iterator path::iterator::operator--(int) {
      auto i = *this;
      --(*this);
      return i;
    }

    GHC_INLINE bool
    path::iterator::operator==(const path::iterator & other) const {
      return _iter == other._iter;
    }

    GHC_INLINE bool
    path::iterator::operator!=(const path::iterator & other) const {
      return _iter != other._iter;
    }

    GHC_INLINE path::iterator::reference path::iterator::operator*() const {
      return _current;
    }

    GHC_INLINE path::iterator::pointer path::iterator::operator->() const {
      return &_current;
    }

    GHC_INLINE path::iterator path::begin() const {
      return iterator(_path.begin(), _path.end(), _path.begin());
    }

    GHC_INLINE path::iterator path::end() const {
      return iterator(_path.begin(), _path.end(), _path.end());
    }

    //-----------------------------------------------------------------------------
    // 30.10.8.6, path non-member functions
    GHC_INLINE void swap(path & lhs, path & rhs) noexcept {
      swap(lhs._path, rhs._path);
    }

    GHC_INLINE size_t hash_value(const path & p) noexcept {
      return std::hash<std::string>()(p.generic_string());
    }

    GHC_INLINE bool operator==(const path & lhs, const path & rhs) noexcept {
      return lhs.generic_string() == rhs.generic_string();
    }

    GHC_INLINE bool operator!=(const path & lhs, const path & rhs) noexcept {
      return lhs.generic_string() != rhs.generic_string();
    }

    GHC_INLINE bool operator<(const path & lhs, const path & rhs) noexcept {
      return lhs.generic_string() < rhs.generic_string();
    }

    GHC_INLINE bool operator<=(const path & lhs, const path & rhs) noexcept {
      return lhs.generic_string() <= rhs.generic_string();
    }

    GHC_INLINE bool operator>(const path & lhs, const path & rhs) noexcept {
      return lhs.generic_string() > rhs.generic_string();
    }

    GHC_INLINE bool operator>=(const path & lhs, const path & rhs) noexcept {
      return lhs.generic_string() >= rhs.generic_string();
    }

    GHC_INLINE path operator/(const path & lhs, const path & rhs) {
      path result(lhs);
      result /= rhs;
      return result;
    }

#endif // GHC_EXPAND_IMPL

    //-----------------------------------------------------------------------------
    // 30.10.8.6.1 path inserter and extractor
    template <class charT, class traits>
    inline std::basic_ostream<charT, traits> &
    operator<<(std::basic_ostream<charT, traits> & os, const path & p) {
      os << "\"";
      auto ps = p.string<charT, traits>();
      for (auto c : ps) {
        if (c == '"' || c == '\\') { os << '\\'; }
        os << c;
      }
      os << "\"";
      return os;
    }

    template <class charT, class traits>
    inline std::basic_istream<charT, traits> &
    operator>>(std::basic_istream<charT, traits> & is, path & p) {
      std::basic_string<charT, traits> tmp;
      charT c;
      is >> c;
      if (c == '"') {
        auto sf = is.flags();
        is >> std::noskipws;
        while (is) {
          auto c2 = is.get();
          if (is) {
            if (c2 == '\\') {
              c2 = is.get();
              if (is) { tmp += static_cast<charT>(c2); }
            } else if (c2 == '"') {
              break;
            } else {
              tmp += static_cast<charT>(c2);
            }
          }
        }
        if ((sf & std::ios_base::skipws) == std::ios_base::skipws) {
          is >> std::skipws;
        }
        p = path(tmp);
      } else {
        is >> tmp;
        p = path(static_cast<charT>(c) + tmp);
      }
      return is;
    }

#ifdef GHC_EXPAND_IMPL

    //-----------------------------------------------------------------------------
    // 30.10.9 Class filesystem_error
    GHC_INLINE filesystem_error::filesystem_error(const std::string & what_arg,
                                                  std::error_code ec)
        : std::system_error(ec, what_arg), _what_arg(what_arg), _ec(ec) {}

    GHC_INLINE filesystem_error::filesystem_error(const std::string & what_arg,
                                                  const path & p1,
                                                  std::error_code ec)
        : std::system_error(ec, what_arg), _what_arg(what_arg), _ec(ec),
          _p1(p1) {
      if (!_p1.empty()) { _what_arg += ": '" + _p1.u8string() + "'"; }
    }

    GHC_INLINE filesystem_error::filesystem_error(const std::string & what_arg,
                                                  const path & p1,
                                                  const path & p2,
                                                  std::error_code ec)
        : std::system_error(ec, what_arg), _what_arg(what_arg), _ec(ec),
          _p1(p1), _p2(p2) {
      if (!_p1.empty()) { _what_arg += ": '" + _p1.u8string() + "'"; }
      if (!_p2.empty()) { _what_arg += ", '" + _p2.u8string() + "'"; }
    }

    GHC_INLINE const path & filesystem_error::path1() const noexcept {
      return _p1;
    }

    GHC_INLINE const path & filesystem_error::path2() const noexcept {
      return _p2;
    }

    GHC_INLINE const char * filesystem_error::what() const noexcept {
      return _what_arg.c_str();
    }

//-----------------------------------------------------------------------------
// 30.10.15, filesystem operations
#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path absolute(const path & p) {
      std::error_code ec;
      path result = absolute(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE path absolute(const path & p, std::error_code & ec) {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      if (p.empty()) { return absolute(current_path(ec), ec) / ""; }
      ULONG size = ::GetFullPathNameW(p.wstring().c_str(), 0, 0, 0);
      if (size) {
        std::vector<wchar_t> buf(size, 0);
        ULONG s2 =
            GetFullPathNameW(p.wstring().c_str(), size, buf.data(), nullptr);
        if (s2 && s2 < size) {
          path result = path(std::wstring(buf.data(), s2));
          if (p.filename() == ".") { result /= "."; }
          return result;
        }
      }
      ec = detail::make_system_error();
      return path();
#else
      path base = current_path(ec);
      if (!ec) {
        if (p.empty()) { return base / p; }
        if (p.has_root_name()) {
          if (p.has_root_directory()) {
            return p;
          } else {
            return p.root_name() / base.root_directory() /
                   base.relative_path() / p.relative_path();
          }
        } else {
          if (p.has_root_directory()) {
            return base.root_name() / p;
          } else {
            return base / p;
          }
        }
      }
      ec = detail::make_system_error();
      return path();
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path canonical(const path & p) {
      std::error_code ec;
      auto result = canonical(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE path canonical(const path & p, std::error_code & ec) {
      if (p.empty()) {
        ec = detail::make_error_code(detail::portable_error::not_found);
        return path();
      }
      path work = p.is_absolute() ? p : absolute(p, ec);
      path root = work.root_path();
      path result;

      auto fs = status(work, ec);
      if (ec) { return path(); }
      if (fs.type() == file_type::not_found) {
        ec = detail::make_error_code(detail::portable_error::not_found);
        return path();
      }
      bool redo;
      do {
        redo = false;
        result.clear();
        for (auto pe : work) {
          if (pe.empty() || pe == ".") {
            continue;
          } else if (pe == "..") {
            result = result.parent_path();
            continue;
          } else if ((result / pe).string().length() <=
                     root.string().length()) {
            result /= pe;
            continue;
          }
          auto sls = symlink_status(result / pe, ec);
          if (ec) { return path(); }
          if (is_symlink(sls)) {
            redo = true;
            auto target = read_symlink(result / pe, ec);
            if (ec) { return path(); }
            if (target.is_absolute()) {
              result = target;
              continue;
            } else {
              result /= target;
              continue;
            }
          } else {
            result /= pe;
          }
        }
        work = result;
      } while (redo);
      ec.clear();
      return result;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void copy(const path & from, const path & to) {
      copy(from, to, copy_options::none);
    }
#endif

    GHC_INLINE void copy(const path & from, const path & to,
                         std::error_code & ec) noexcept {
      copy(from, to, copy_options::none, ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void copy(const path & from, const path & to,
                         copy_options options) {
      std::error_code ec;
      copy(from, to, options, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), from, to,
                               ec);
      }
    }
#endif

    GHC_INLINE void copy(const path & from, const path & to,
                         copy_options options, std::error_code & ec) noexcept {
      std::error_code tec;
      file_status fs_from, fs_to;
      ec.clear();
      if ((options &
           (copy_options::skip_symlinks | copy_options::copy_symlinks |
            copy_options::create_symlinks)) != copy_options::none) {
        fs_from = symlink_status(from, ec);
      } else {
        fs_from = status(from, ec);
      }
      if (!exists(fs_from)) {
        if (!ec) {
          ec = detail::make_error_code(detail::portable_error::not_found);
        }
        return;
      }
      if ((options & (copy_options::skip_symlinks |
                      copy_options::create_symlinks)) != copy_options::none) {
        fs_to = symlink_status(to, tec);
      } else {
        fs_to = status(to, tec);
      }
      if (is_other(fs_from) || is_other(fs_to) ||
          (is_directory(fs_from) && is_regular_file(fs_to)) ||
          (exists(fs_to) && equivalent(from, to, ec))) {
        ec = detail::make_error_code(detail::portable_error::invalid_argument);
      } else if (is_symlink(fs_from)) {
        if ((options & copy_options::skip_symlinks) == copy_options::none) {
          if (!exists(fs_to) &&
              (options & copy_options::copy_symlinks) != copy_options::none) {
            copy_symlink(from, to, ec);
          } else {
            ec = detail::make_error_code(
                detail::portable_error::invalid_argument);
          }
        }
      } else if (is_regular_file(fs_from)) {
        if ((options & copy_options::directories_only) == copy_options::none) {
          if ((options & copy_options::create_symlinks) != copy_options::none) {
            create_symlink(from.is_absolute() ? from : canonical(from, ec), to,
                           ec);
          }
#ifndef GHC_OS_WEB
          else if ((options & copy_options::create_hard_links) !=
                   copy_options::none) {
            create_hard_link(from, to, ec);
          }
#endif
          else if (is_directory(fs_to)) {
            copy_file(from, to / from.filename(), options, ec);
          } else {
            copy_file(from, to, options, ec);
          }
        }
      }
#ifdef LWG_2682_BEHAVIOUR
      else if (is_directory(fs_from) &&
               (options & copy_options::create_symlinks) !=
                   copy_options::none) {
        ec = detail::make_error_code(detail::portable_error::is_a_directory);
      }
#endif
      else if (is_directory(fs_from) &&
               (options == copy_options::none ||
                (options & copy_options::recursive) != copy_options::none)) {
        if (!exists(fs_to)) {
          create_directory(to, from, ec);
          if (ec) { return; }
        }
        for (auto iter = directory_iterator(from, ec);
             iter != directory_iterator(); iter.increment(ec)) {
          if (!ec) {
            copy(iter->path(), to / iter->path().filename(),
                 options | static_cast<copy_options>(0x8000), ec);
          }
          if (ec) { return; }
        }
      }
      return;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool copy_file(const path & from, const path & to) {
      return copy_file(from, to, copy_options::none);
    }
#endif

    GHC_INLINE bool copy_file(const path & from, const path & to,
                              std::error_code & ec) noexcept {
      return copy_file(from, to, copy_options::none, ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool copy_file(const path & from, const path & to,
                              copy_options option) {
      std::error_code ec;
      auto result = copy_file(from, to, option, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), from, to,
                               ec);
      }
      return result;
    }
#endif

    GHC_INLINE bool copy_file(const path & from, const path & to,
                              copy_options options,
                              std::error_code & ec) noexcept {
      std::error_code tecf, tect;
      auto sf = status(from, tecf);
      auto st = status(to, tect);
      bool overwrite = false;
      ec.clear();
      if (!is_regular_file(sf)) {
        ec = tecf;
        return false;
      }
      if (exists(st) &&
          (!is_regular_file(st) || equivalent(from, to, ec) ||
           (options &
            (copy_options::skip_existing | copy_options::overwrite_existing |
             copy_options::update_existing)) == copy_options::none)) {
        ec = tect ? tect
                  : detail::make_error_code(detail::portable_error::exists);
        return false;
      }
      if (exists(st)) {
        if ((options & copy_options::update_existing) ==
            copy_options::update_existing) {
          auto from_time = last_write_time(from, ec);
          if (ec) {
            ec = detail::make_system_error();
            return false;
          }
          auto to_time = last_write_time(to, ec);
          if (ec) {
            ec = detail::make_system_error();
            return false;
          }
          if (from_time <= to_time) { return false; }
        }
        overwrite = true;
      }
#ifdef GHC_OS_WINDOWS
      if (!::CopyFileW(detail::fromUtf8<std::wstring>(from.u8string()).c_str(),
                       detail::fromUtf8<std::wstring>(to.u8string()).c_str(),
                       !overwrite)) {
        ec = detail::make_system_error();
        return false;
      }
      return true;
#else
      std::vector<char> buffer(16384, '\0');
      int in = -1, out = -1;
      if ((in = ::open(from.c_str(), O_RDONLY)) < 0) {
        ec = detail::make_system_error();
        return false;
      }
      int mode = O_CREAT | O_WRONLY | O_TRUNC;
      if (!overwrite) { mode |= O_EXCL; }
      if ((out = ::open(to.c_str(), mode,
                        static_cast<int>(sf.permissions() & perms::all))) < 0) {
        ec = detail::make_system_error();
        ::close(in);
        return false;
      }
      ssize_t br, bw;
      while ((br = ::read(in, buffer.data(), buffer.size())) > 0) {
        ssize_t offset = 0;
        do {
          if ((bw = ::write(out, buffer.data() + offset,
                            static_cast<size_t>(br))) > 0) {
            br -= bw;
            offset += bw;
          } else if (bw < 0) {
            ec = detail::make_system_error();
            ::close(in);
            ::close(out);
            return false;
          }
        } while (br);
      }
      ::close(in);
      ::close(out);
      return true;
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void copy_symlink(const path & existing_symlink,
                                 const path & new_symlink) {
      std::error_code ec;
      copy_symlink(existing_symlink, new_symlink, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()),
                               existing_symlink, new_symlink, ec);
      }
    }
#endif

    GHC_INLINE void copy_symlink(const path & existing_symlink,
                                 const path & new_symlink,
                                 std::error_code & ec) noexcept {
      ec.clear();
      auto to = read_symlink(existing_symlink, ec);
      if (!ec) {
        if (exists(to, ec) && is_directory(to, ec)) {
          create_directory_symlink(to, new_symlink, ec);
        } else {
          create_symlink(to, new_symlink, ec);
        }
      }
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool create_directories(const path & p) {
      std::error_code ec;
      auto result = create_directories(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE bool create_directories(const path & p,
                                       std::error_code & ec) noexcept {
      path current;
      ec.clear();
      bool didCreate = false;
      for (path::string_type part : p) {
        current /= part;
        if (current != p.root_name() && current != p.root_path()) {
          std::error_code tec;
          auto fs = status(current, tec);
          if (tec && fs.type() != file_type::not_found) {
            ec = tec;
            return false;
          }
          if (!exists(fs)) {
            create_directory(current, ec);
            if (ec) {
              std::error_code tmp_ec;
              if (is_directory(current, tmp_ec)) {
                ec.clear();
              } else {
                return false;
              }
            }
            didCreate = true;
          }
#ifndef LWG_2935_BEHAVIOUR
          else if (!is_directory(fs)) {
            ec = detail::make_error_code(detail::portable_error::exists);
            return false;
          }
#endif
        }
      }
      return didCreate;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool create_directory(const path & p) {
      std::error_code ec;
      auto result = create_directory(p, path(), ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE bool create_directory(const path & p,
                                     std::error_code & ec) noexcept {
      return create_directory(p, path(), ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool create_directory(const path & p, const path & attributes) {
      std::error_code ec;
      auto result = create_directory(p, attributes, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE bool create_directory(const path & p, const path & attributes,
                                     std::error_code & ec) noexcept {
      std::error_code tec;
      ec.clear();
      auto fs = status(p, tec);
#ifdef LWG_2935_BEHAVIOUR
      if (status_known(fs) && exists(fs)) { return false; }
#else
      if (status_known(fs) && exists(fs) && is_directory(fs)) { return false; }
#endif
#ifdef GHC_OS_WINDOWS
      if (!attributes.empty()) {
        if (!::CreateDirectoryExW(
                detail::fromUtf8<std::wstring>(attributes.u8string()).c_str(),
                detail::fromUtf8<std::wstring>(p.u8string()).c_str(), NULL)) {
          ec = detail::make_system_error();
          return false;
        }
      } else if (!::CreateDirectoryW(
                     detail::fromUtf8<std::wstring>(p.u8string()).c_str(),
                     NULL)) {
        ec = detail::make_system_error();
        return false;
      }
#else
      ::mode_t attribs = static_cast<mode_t>(perms::all);
      if (!attributes.empty()) {
        struct ::stat fileStat;
        if (::stat(attributes.c_str(), &fileStat) != 0) {
          ec = detail::make_system_error();
          return false;
        }
        attribs = fileStat.st_mode;
      }
      if (::mkdir(p.c_str(), attribs) != 0) {
        ec = detail::make_system_error();
        return false;
      }
#endif
      return true;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void create_directory_symlink(const path & to,
                                             const path & new_symlink) {
      std::error_code ec;
      create_directory_symlink(to, new_symlink, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), to,
                               new_symlink, ec);
      }
    }
#endif

    GHC_INLINE void create_directory_symlink(const path & to,
                                             const path & new_symlink,
                                             std::error_code & ec) noexcept {
      detail::create_symlink(to, new_symlink, true, ec);
    }

#ifndef GHC_OS_WEB
#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void create_hard_link(const path & to,
                                     const path & new_hard_link) {
      std::error_code ec;
      create_hard_link(to, new_hard_link, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), to,
                               new_hard_link, ec);
      }
    }
#endif

    GHC_INLINE void create_hard_link(const path & to,
                                     const path & new_hard_link,
                                     std::error_code & ec) noexcept {
      detail::create_hardlink(to, new_hard_link, ec);
    }
#endif

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void create_symlink(const path & to, const path & new_symlink) {
      std::error_code ec;
      create_symlink(to, new_symlink, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), to,
                               new_symlink, ec);
      }
    }
#endif

    GHC_INLINE void create_symlink(const path & to, const path & new_symlink,
                                   std::error_code & ec) noexcept {
      detail::create_symlink(to, new_symlink, false, ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path current_path() {
      std::error_code ec;
      auto result = current_path(ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), ec);
      }
      return result;
    }
#endif

    GHC_INLINE path current_path(std::error_code & ec) {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      DWORD pathlen = ::GetCurrentDirectoryW(0, 0);
      std::unique_ptr<wchar_t[]> buffer(new wchar_t[size_t(pathlen) + 1]);
      if (::GetCurrentDirectoryW(pathlen, buffer.get()) == 0) {
        ec = detail::make_system_error();
        return path();
      }
      return path(std::wstring(buffer.get()), path::native_format);
#else
      size_t pathlen = static_cast<size_t>(
          std::max(int(::pathconf(".", _PC_PATH_MAX)), int(PATH_MAX)));
      std::unique_ptr<char[]> buffer(new char[pathlen + 1]);
      if (::getcwd(buffer.get(), pathlen) == nullptr) {
        ec = detail::make_system_error();
        return path();
      }
      return path(buffer.get());
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void current_path(const path & p) {
      std::error_code ec;
      current_path(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
    }
#endif

    GHC_INLINE void current_path(const path & p,
                                 std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      if (!::SetCurrentDirectoryW(
              detail::fromUtf8<std::wstring>(p.u8string()).c_str())) {
        ec = detail::make_system_error();
      }
#else
      if (::chdir(p.string().c_str()) == -1) {
        ec = detail::make_system_error();
      }
#endif
    }

    GHC_INLINE bool exists(file_status s) noexcept {
      return status_known(s) && s.type() != file_type::not_found;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool exists(const path & p) { return exists(status(p)); }
#endif

    GHC_INLINE bool exists(const path & p, std::error_code & ec) noexcept {
      file_status s = status(p, ec);
      if (status_known(s)) { ec.clear(); }
      return exists(s);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool equivalent(const path & p1, const path & p2) {
      std::error_code ec;
      bool result = equivalent(p1, p2, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p1, p2, ec);
      }
      return result;
    }
#endif

    GHC_INLINE bool equivalent(const path & p1, const path & p2,
                               std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      std::shared_ptr<void> file1(
          ::CreateFileW(p1.wstring().c_str(), 0,
                        FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
                        0, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0),
          CloseHandle);
      auto e1 = ::GetLastError();
      std::shared_ptr<void> file2(
          ::CreateFileW(p2.wstring().c_str(), 0,
                        FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
                        0, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0),
          CloseHandle);
      if (file1.get() == INVALID_HANDLE_VALUE ||
          file2.get() == INVALID_HANDLE_VALUE) {
#ifdef LWG_2937_BEHAVIOUR
        ec = detail::make_system_error(e1 ? e1 : ::GetLastError());
#else
        if (file1 == file2) {
          ec = detail::make_system_error(e1 ? e1 : ::GetLastError());
        }
#endif
        return false;
      }
      BY_HANDLE_FILE_INFORMATION inf1, inf2;
      if (!::GetFileInformationByHandle(file1.get(), &inf1)) {
        ec = detail::make_system_error();
        return false;
      }
      if (!::GetFileInformationByHandle(file2.get(), &inf2)) {
        ec = detail::make_system_error();
        return false;
      }
      return inf1.ftLastWriteTime.dwLowDateTime ==
                 inf2.ftLastWriteTime.dwLowDateTime &&
             inf1.ftLastWriteTime.dwHighDateTime ==
                 inf2.ftLastWriteTime.dwHighDateTime &&
             inf1.nFileIndexHigh == inf2.nFileIndexHigh &&
             inf1.nFileIndexLow == inf2.nFileIndexLow &&
             inf1.nFileSizeHigh == inf2.nFileSizeHigh &&
             inf1.nFileSizeLow == inf2.nFileSizeLow &&
             inf1.dwVolumeSerialNumber == inf2.dwVolumeSerialNumber;
#else
      struct ::stat s1, s2;
      auto rc1 = ::stat(p1.c_str(), &s1);
      auto e1 = errno;
      auto rc2 = ::stat(p2.c_str(), &s2);
      if (rc1 || rc2) {
#ifdef LWG_2937_BEHAVIOUR
        ec = detail::make_system_error(e1 ? e1 : errno);
#else
        if (rc1 && rc2) { ec = detail::make_system_error(e1 ? e1 : errno); }
#endif
        return false;
      }
      return s1.st_dev == s2.st_dev && s1.st_ino == s2.st_ino &&
             s1.st_size == s2.st_size && s1.st_mtime == s2.st_mtime;
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE uintmax_t file_size(const path & p) {
      std::error_code ec;
      auto result = file_size(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE uintmax_t file_size(const path & p,
                                   std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      WIN32_FILE_ATTRIBUTE_DATA attr;
      if (!GetFileAttributesExW(
              detail::fromUtf8<std::wstring>(p.u8string()).c_str(),
              GetFileExInfoStandard, &attr)) {
        ec = detail::make_system_error();
        return static_cast<uintmax_t>(-1);
      }
      return static_cast<uintmax_t>(attr.nFileSizeHigh)
                 << (sizeof(attr.nFileSizeHigh) * 8) |
             attr.nFileSizeLow;
#else
      struct ::stat fileStat;
      if (::stat(p.c_str(), &fileStat) == -1) {
        ec = detail::make_system_error();
        return static_cast<uintmax_t>(-1);
      }
      return static_cast<uintmax_t>(fileStat.st_size);
#endif
    }

#ifndef GHC_OS_WEB
#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE uintmax_t hard_link_count(const path & p) {
      std::error_code ec;
      auto result = hard_link_count(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE uintmax_t hard_link_count(const path & p,
                                         std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      uintmax_t result = static_cast<uintmax_t>(-1);
      std::shared_ptr<void> file(
          ::CreateFileW(p.wstring().c_str(), 0,
                        FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
                        0, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0),
          CloseHandle);
      BY_HANDLE_FILE_INFORMATION inf;
      if (file.get() == INVALID_HANDLE_VALUE) {
        ec = detail::make_system_error();
      } else {
        if (!::GetFileInformationByHandle(file.get(), &inf)) {
          ec = detail::make_system_error();
        } else {
          result = inf.nNumberOfLinks;
        }
      }
      return result;
#else
      uintmax_t result = 0;
      file_status fs =
          detail::status_ex(p, ec, nullptr, nullptr, &result, nullptr);
      if (fs.type() == file_type::not_found) {
        ec = detail::make_error_code(detail::portable_error::not_found);
      }
      return ec ? static_cast<uintmax_t>(-1) : result;
#endif
    }
#endif

    GHC_INLINE bool is_block_file(file_status s) noexcept {
      return s.type() == file_type::block;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_block_file(const path & p) {
      return is_block_file(status(p));
    }
#endif

    GHC_INLINE bool is_block_file(const path & p,
                                  std::error_code & ec) noexcept {
      return is_block_file(status(p, ec));
    }

    GHC_INLINE bool is_character_file(file_status s) noexcept {
      return s.type() == file_type::character;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_character_file(const path & p) {
      return is_character_file(status(p));
    }
#endif

    GHC_INLINE bool is_character_file(const path & p,
                                      std::error_code & ec) noexcept {
      return is_character_file(status(p, ec));
    }

    GHC_INLINE bool is_directory(file_status s) noexcept {
      return s.type() == file_type::directory;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_directory(const path & p) {
      return is_directory(status(p));
    }
#endif

    GHC_INLINE bool is_directory(const path & p,
                                 std::error_code & ec) noexcept {
      return is_directory(status(p, ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_empty(const path & p) {
      if (is_directory(p)) {
        return directory_iterator(p) == directory_iterator();
      } else {
        return file_size(p) == 0;
      }
    }
#endif

    GHC_INLINE bool is_empty(const path & p, std::error_code & ec) noexcept {
      auto fs = status(p, ec);
      if (ec) { return false; }
      if (is_directory(fs)) {
        directory_iterator iter(p, ec);
        if (ec) { return false; }
        return iter == directory_iterator();
      } else {
        auto sz = file_size(p, ec);
        if (ec) { return false; }
        return sz == 0;
      }
    }

    GHC_INLINE bool is_fifo(file_status s) noexcept {
      return s.type() == file_type::fifo;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_fifo(const path & p) { return is_fifo(status(p)); }
#endif

    GHC_INLINE bool is_fifo(const path & p, std::error_code & ec) noexcept {
      return is_fifo(status(p, ec));
    }

    GHC_INLINE bool is_other(file_status s) noexcept {
      return exists(s) && !is_regular_file(s) && !is_directory(s) &&
             !is_symlink(s);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_other(const path & p) { return is_other(status(p)); }
#endif

    GHC_INLINE bool is_other(const path & p, std::error_code & ec) noexcept {
      return is_other(status(p, ec));
    }

    GHC_INLINE bool is_regular_file(file_status s) noexcept {
      return s.type() == file_type::regular;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_regular_file(const path & p) {
      return is_regular_file(status(p));
    }
#endif

    GHC_INLINE bool is_regular_file(const path & p,
                                    std::error_code & ec) noexcept {
      return is_regular_file(status(p, ec));
    }

    GHC_INLINE bool is_socket(file_status s) noexcept {
      return s.type() == file_type::socket;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_socket(const path & p) { return is_socket(status(p)); }
#endif

    GHC_INLINE bool is_socket(const path & p, std::error_code & ec) noexcept {
      return is_socket(status(p, ec));
    }

    GHC_INLINE bool is_symlink(file_status s) noexcept {
      return s.type() == file_type::symlink;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool is_symlink(const path & p) {
      return is_symlink(symlink_status(p));
    }
#endif

    GHC_INLINE bool is_symlink(const path & p, std::error_code & ec) noexcept {
      return is_symlink(symlink_status(p, ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE file_time_type last_write_time(const path & p) {
      std::error_code ec;
      auto result = last_write_time(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE file_time_type last_write_time(const path & p,
                                              std::error_code & ec) noexcept {
      time_t result = 0;
      ec.clear();
      file_status fs =
          detail::status_ex(p, ec, nullptr, nullptr, nullptr, &result);
      return ec ? (file_time_type::min)()
                : std::chrono::system_clock::from_time_t(result);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void last_write_time(const path & p, file_time_type new_time) {
      std::error_code ec;
      last_write_time(p, new_time, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
    }
#endif

    GHC_INLINE void last_write_time(const path & p, file_time_type new_time,
                                    std::error_code & ec) noexcept {
      ec.clear();
      auto d = new_time.time_since_epoch();
#ifdef GHC_OS_WINDOWS
      std::shared_ptr<void> file(
          ::CreateFileW(p.wstring().c_str(), FILE_WRITE_ATTRIBUTES,
                        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
                        NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL),
          ::CloseHandle);
      FILETIME ft;
      auto tt =
          std::chrono::duration_cast<std::chrono::microseconds>(d).count() *
              10 +
          116444736000000000;
      ft.dwLowDateTime = static_cast<DWORD>(tt);
      ft.dwHighDateTime = static_cast<DWORD>(tt >> 32);
      if (!::SetFileTime(file.get(), 0, 0, &ft)) {
        ec = detail::make_system_error();
      }
#elif defined(GHC_OS_MACOS)
#ifdef __MAC_OS_X_VERSION_MIN_REQUIRED
#if __MAC_OS_X_VERSION_MIN_REQUIRED < 101300
      struct ::stat fs;
      if (::stat(p.c_str(), &fs) == 0) {
        struct ::timeval tv[2];
        tv[0].tv_sec = fs.st_atimespec.tv_sec;
        tv[0].tv_usec = static_cast<int>(fs.st_atimespec.tv_nsec / 1000);
        tv[1].tv_sec =
            std::chrono::duration_cast<std::chrono::seconds>(d).count();
        tv[1].tv_usec = static_cast<int>(
            std::chrono::duration_cast<std::chrono::microseconds>(d).count() %
            1000000);
        if (::utimes(p.c_str(), tv) == 0) { return; }
      }
      ec = detail::make_system_error();
      return;
#else
      struct ::timespec times[2];
      times[0].tv_sec = 0;
      times[0].tv_nsec = UTIME_OMIT;
      times[1].tv_sec =
          std::chrono::duration_cast<std::chrono::seconds>(d).count();
      times[1].tv_nsec =
          0; // std::chrono::duration_cast<std::chrono::nanoseconds>(d).count()
             // % 1000000000;
      if (::utimensat(AT_FDCWD, p.c_str(), times, AT_SYMLINK_NOFOLLOW) != 0) {
        ec = detail::make_system_error();
      }
      return;
#endif
#endif
#else
#ifndef UTIME_OMIT
#define UTIME_OMIT ((1l << 30) - 2l)
#endif
      struct ::timespec times[2];
      times[0].tv_sec = 0;
      times[0].tv_nsec = UTIME_OMIT;
      times[1].tv_sec = static_cast<decltype(times[1].tv_sec)>(
          std::chrono::duration_cast<std::chrono::seconds>(d).count());
      times[1].tv_nsec = static_cast<decltype(times[1].tv_nsec)>(
          std::chrono::duration_cast<std::chrono::nanoseconds>(d).count() %
          1000000000);
#if defined(__ANDROID_API__) && __ANDROID_API__ < 12
      if (syscall(__NR_utimensat, AT_FDCWD, p.c_str(), times,
                  AT_SYMLINK_NOFOLLOW) != 0) {
#else
      if (::utimensat(AT_FDCWD, p.c_str(), times, AT_SYMLINK_NOFOLLOW) != 0) {
#endif
        ec = detail::make_system_error();
      }
      return;
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void permissions(const path & p, perms prms, perm_options opts) {
      std::error_code ec;
      permissions(p, prms, opts, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
    }
#endif

    GHC_INLINE void permissions(const path & p, perms prms,
                                std::error_code & ec) noexcept {
      permissions(p, prms, perm_options::replace, ec);
    }

    GHC_INLINE void permissions(const path & p, perms prms, perm_options opts,
                                std::error_code & ec) {
      if (static_cast<int>(opts & (perm_options::replace | perm_options::add |
                                   perm_options::remove)) == 0) {
        ec = detail::make_error_code(detail::portable_error::invalid_argument);
        return;
      }
      auto fs = symlink_status(p, ec);
      if ((opts & perm_options::replace) != perm_options::replace) {
        if ((opts & perm_options::add) == perm_options::add) {
          prms = fs.permissions() | prms;
        } else {
          prms = fs.permissions() & ~prms;
        }
      }
#ifdef GHC_OS_WINDOWS
#ifdef __GNUC__
      auto oldAttr = GetFileAttributesW(p.wstring().c_str());
      if (oldAttr != INVALID_FILE_ATTRIBUTES) {
        DWORD newAttr =
            ((prms & perms::owner_write) == perms::owner_write)
                ? oldAttr & ~(static_cast<DWORD>(FILE_ATTRIBUTE_READONLY))
                : oldAttr | FILE_ATTRIBUTE_READONLY;
        if (oldAttr == newAttr ||
            SetFileAttributesW(p.wstring().c_str(), newAttr)) {
          return;
        }
      }
      ec = detail::make_system_error();
#else
      int mode = 0;
      if ((prms & perms::owner_read) == perms::owner_read) { mode |= _S_IREAD; }
      if ((prms & perms::owner_write) == perms::owner_write) {
        mode |= _S_IWRITE;
      }
      if (::_wchmod(p.wstring().c_str(), mode) != 0) {
        ec = detail::make_system_error();
      }
#endif
#else
      if ((opts & perm_options::nofollow) != perm_options::nofollow) {
        if (::chmod(p.c_str(), static_cast<mode_t>(prms)) != 0) {
          ec = detail::make_system_error();
        }
      }
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path proximate(const path & p, std::error_code & ec) {
      return proximate(p, current_path(), ec);
    }
#endif

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path proximate(const path & p, const path & base) {
      return weakly_canonical(p).lexically_proximate(weakly_canonical(base));
    }
#endif

    GHC_INLINE path proximate(const path & p, const path & base,
                              std::error_code & ec) {
      return weakly_canonical(p, ec).lexically_proximate(
          weakly_canonical(base, ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path read_symlink(const path & p) {
      std::error_code ec;
      auto result = read_symlink(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE path read_symlink(const path & p, std::error_code & ec) {
      file_status fs = symlink_status(p, ec);
      if (fs.type() != file_type::symlink) {
        ec = detail::make_error_code(detail::portable_error::invalid_argument);
        return path();
      }
      auto result = detail::resolveSymlink(p, ec);
      return ec ? path() : result;
    }

    GHC_INLINE path relative(const path & p, std::error_code & ec) {
      return relative(p, current_path(ec), ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path relative(const path & p, const path & base) {
      return weakly_canonical(p).lexically_relative(weakly_canonical(base));
    }
#endif

    GHC_INLINE path relative(const path & p, const path & base,
                             std::error_code & ec) {
      return weakly_canonical(p, ec).lexically_relative(
          weakly_canonical(base, ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool remove(const path & p) {
      std::error_code ec;
      auto result = remove(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE bool remove(const path & p, std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      std::wstring np = detail::fromUtf8<std::wstring>(p.u8string());
      DWORD attr = GetFileAttributesW(np.c_str());
      if (attr == INVALID_FILE_ATTRIBUTES) {
        auto error = ::GetLastError();
        if (error == ERROR_FILE_NOT_FOUND || error == ERROR_PATH_NOT_FOUND) {
          return false;
        }
        ec = detail::make_system_error(error);
      }
      if (!ec) {
        if (attr & FILE_ATTRIBUTE_DIRECTORY) {
          if (!RemoveDirectoryW(np.c_str())) {
            ec = detail::make_system_error();
          }
        } else {
          if (!DeleteFileW(np.c_str())) { ec = detail::make_system_error(); }
        }
      }
#else
      if (::remove(p.c_str()) == -1) {
        auto error = errno;
        if (error == ENOENT) { return false; }
        ec = detail::make_system_error();
      }
#endif
      return ec ? false : true;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE uintmax_t remove_all(const path & p) {
      std::error_code ec;
      auto result = remove_all(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE uintmax_t remove_all(const path & p,
                                    std::error_code & ec) noexcept {
      ec.clear();
      uintmax_t count = 0;
      if (p == "/") {
        ec = detail::make_error_code(detail::portable_error::not_supported);
        return static_cast<uintmax_t>(-1);
      }
      std::error_code tec;
      auto fs = status(p, tec);
      if (exists(fs) && is_directory(fs)) {
        for (auto iter = directory_iterator(p, ec);
             iter != directory_iterator(); iter.increment(ec)) {
          if (ec) { break; }
          bool is_symlink_result = iter->is_symlink(ec);
          if (ec) return static_cast<uintmax_t>(-1);
          bool is_directory_result = iter->is_directory(ec);
          if (ec) return static_cast<uintmax_t>(-1);
          if (!is_symlink_result && is_directory_result) {
            count += remove_all(iter->path(), ec);
            if (ec) { return static_cast<uintmax_t>(-1); }
          } else {
            remove(iter->path(), ec);
            if (ec) { return static_cast<uintmax_t>(-1); }
            ++count;
          }
        }
      }
      if (!ec) {
        if (remove(p, ec)) { ++count; }
      }
      if (ec) { return static_cast<uintmax_t>(-1); }
      return count;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void rename(const path & from, const path & to) {
      std::error_code ec;
      rename(from, to, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), from, to,
                               ec);
      }
    }
#endif

    GHC_INLINE void rename(const path & from, const path & to,
                           std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      if (from != to) {
        if (!MoveFileExW(
                detail::fromUtf8<std::wstring>(from.u8string()).c_str(),
                detail::fromUtf8<std::wstring>(to.u8string()).c_str(),
                (DWORD)MOVEFILE_REPLACE_EXISTING)) {
          ec = detail::make_system_error();
        }
      }
#else
      if (from != to) {
        if (::rename(from.c_str(), to.c_str()) != 0) {
          ec = detail::make_system_error();
        }
      }
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void resize_file(const path & p, uintmax_t size) {
      std::error_code ec;
      resize_file(p, size, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
    }
#endif

    GHC_INLINE void resize_file(const path & p, uintmax_t size,
                                std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      LARGE_INTEGER lisize;
      lisize.QuadPart = static_cast<LONGLONG>(size);
      if (lisize.QuadPart < 0) {
#ifdef ERROR_FILE_TOO_LARGE
        ec = detail::make_system_error(ERROR_FILE_TOO_LARGE);
#else
        ec = detail::make_system_error(223);
#endif
        return;
      }
      std::shared_ptr<void> file(
          CreateFileW(detail::fromUtf8<std::wstring>(p.u8string()).c_str(),
                      GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL),
          CloseHandle);
      if (file.get() == INVALID_HANDLE_VALUE) {
        ec = detail::make_system_error();
      } else if (SetFilePointerEx(file.get(), lisize, NULL, FILE_BEGIN) == 0 ||
                 SetEndOfFile(file.get()) == 0) {
        ec = detail::make_system_error();
      }
#else
      if (::truncate(p.c_str(), static_cast<off_t>(size)) != 0) {
        ec = detail::make_system_error();
      }
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE space_info space(const path & p) {
      std::error_code ec;
      auto result = space(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE space_info space(const path & p, std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      ULARGE_INTEGER freeBytesAvailableToCaller = {{ 0, 0 }};
      ULARGE_INTEGER totalNumberOfBytes = {{ 0, 0 }};
      ULARGE_INTEGER totalNumberOfFreeBytes = {{ 0, 0 }};
      if (!GetDiskFreeSpaceExW(
              detail::fromUtf8<std::wstring>(p.u8string()).c_str(),
              &freeBytesAvailableToCaller, &totalNumberOfBytes,
              &totalNumberOfFreeBytes)) {
        ec = detail::make_system_error();
        return {static_cast<uintmax_t>(-1), static_cast<uintmax_t>(-1),
                static_cast<uintmax_t>(-1)};
      }
      return {static_cast<uintmax_t>(totalNumberOfBytes.QuadPart),
              static_cast<uintmax_t>(totalNumberOfFreeBytes.QuadPart),
              static_cast<uintmax_t>(freeBytesAvailableToCaller.QuadPart)};
#else
      struct ::statvfs sfs;
      if (::statvfs(p.c_str(), &sfs) != 0) {
        ec = detail::make_system_error();
        return {static_cast<uintmax_t>(-1), static_cast<uintmax_t>(-1),
                static_cast<uintmax_t>(-1)};
      }
      return {static_cast<uintmax_t>(sfs.f_blocks * sfs.f_frsize),
              static_cast<uintmax_t>(sfs.f_bfree * sfs.f_frsize),
              static_cast<uintmax_t>(sfs.f_bavail * sfs.f_frsize)};
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE file_status status(const path & p) {
      std::error_code ec;
      auto result = status(p, ec);
      if (result.type() == file_type::none) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE file_status status(const path & p,
                                  std::error_code & ec) noexcept {
      return detail::status_ex(p, ec);
    }

    GHC_INLINE bool status_known(file_status s) noexcept {
      return s.type() != file_type::none;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE file_status symlink_status(const path & p) {
      std::error_code ec;
      auto result = symlink_status(p, ec);
      if (result.type() == file_type::none) {
        throw filesystem_error(detail::systemErrorText(ec.value()), ec);
      }
      return result;
    }
#endif

    GHC_INLINE file_status symlink_status(const path & p,
                                          std::error_code & ec) noexcept {
      return detail::symlink_status_ex(p, ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path temp_directory_path() {
      std::error_code ec;
      path result = temp_directory_path(ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), ec);
      }
      return result;
    }
#endif

    GHC_INLINE path temp_directory_path(std::error_code & ec) noexcept {
      ec.clear();
#ifdef GHC_OS_WINDOWS
      wchar_t buffer[512];
      auto rc = GetTempPathW(511, buffer);
      if (!rc || rc > 511) {
        ec = detail::make_system_error();
        return path();
      }
      return path(std::wstring(buffer));
#else
      static const char * temp_vars[] = {"TMPDIR", "TMP", "TEMP", "TEMPDIR",
                                         nullptr};
      const char * temp_path = nullptr;
      for (auto temp_name = temp_vars; *temp_name != nullptr; ++temp_name) {
        temp_path = std::getenv(*temp_name);
        if (temp_path) { return path(temp_path); }
      }
      return path("/tmp");
#endif
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE path weakly_canonical(const path & p) {
      std::error_code ec;
      auto result = weakly_canonical(p, ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), p, ec);
      }
      return result;
    }
#endif

    GHC_INLINE path weakly_canonical(const path & p,
                                     std::error_code & ec) noexcept {
      path result;
      ec.clear();
      bool scan = true;
      for (auto pe : p) {
        if (scan) {
          std::error_code tec;
          if (exists(result / pe, tec)) {
            result /= pe;
          } else {
            if (ec) { return path(); }
            scan = false;
            if (!result.empty()) {
              result = canonical(result, ec) / pe;
              if (ec) { break; }
            } else {
              result /= pe;
            }
          }
        } else {
          result /= pe;
        }
      }
      if (scan) {
        if (!result.empty()) { result = canonical(result, ec); }
      }
      return ec ? path() : result.lexically_normal();
    }

    //-----------------------------------------------------------------------------
    // 30.10.11 class file_status
    // 30.10.11.1 constructors and destructor
    GHC_INLINE file_status::file_status() noexcept
        : file_status(file_type::none) {}

    GHC_INLINE file_status::file_status(file_type ft, perms prms) noexcept
        : _type(ft), _perms(prms) {}

    GHC_INLINE file_status::file_status(const file_status & other) noexcept
        : _type(other._type), _perms(other._perms) {}

    GHC_INLINE file_status::file_status(file_status && other) noexcept
        : _type(other._type), _perms(other._perms) {}

    GHC_INLINE file_status::~file_status() {}

    // assignments:
    GHC_INLINE file_status &
    file_status::operator=(const file_status & rhs) noexcept {
      _type = rhs._type;
      _perms = rhs._perms;
      return *this;
    }

    GHC_INLINE file_status &
    file_status::operator=(file_status && rhs) noexcept {
      _type = rhs._type;
      _perms = rhs._perms;
      return *this;
    }

    // 30.10.11.3 modifiers
    GHC_INLINE void file_status::type(file_type ft) noexcept { _type = ft; }

    GHC_INLINE void file_status::permissions(perms prms) noexcept {
      _perms = prms;
    }

    // 30.10.11.2 observers
    GHC_INLINE file_type file_status::type() const noexcept { return _type; }

    GHC_INLINE perms file_status::permissions() const noexcept {
      return _perms;
    }

//-----------------------------------------------------------------------------
// 30.10.12 class directory_entry
// 30.10.12.1 constructors and destructor
// directory_entry::directory_entry() noexcept = default;
// directory_entry::directory_entry(const directory_entry&) = default;
// directory_entry::directory_entry(directory_entry&&) noexcept = default;
#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE directory_entry::directory_entry(const filesystem::path & p)
        : _path(p), _file_size(0)
#ifndef GHC_OS_WINDOWS
          ,
          _hard_link_count(0)
#endif
          ,
          _last_write_time(0) {
      refresh();
    }
#endif

    GHC_INLINE directory_entry::directory_entry(const filesystem::path & p,
                                                std::error_code & ec)
        : _path(p), _file_size(0)
#ifndef GHC_OS_WINDOWS
          ,
          _hard_link_count(0)
#endif
          ,
          _last_write_time(0) {
      refresh(ec);
    }

    GHC_INLINE directory_entry::~directory_entry() {}

// assignments:
// directory_entry& directory_entry::operator=(const directory_entry&) =
// default; directory_entry& directory_entry::operator=(directory_entry&&)
// noexcept = default;

// 30.10.12.2 directory_entry modifiers
#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void directory_entry::assign(const filesystem::path & p) {
      _path = p;
      refresh();
    }
#endif

    GHC_INLINE void directory_entry::assign(const filesystem::path & p,
                                            std::error_code & ec) {
      _path = p;
      refresh(ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void
    directory_entry::replace_filename(const filesystem::path & p) {
      _path.replace_filename(p);
      refresh();
    }
#endif

    GHC_INLINE void
    directory_entry::replace_filename(const filesystem::path & p,
                                      std::error_code & ec) {
      _path.replace_filename(p);
      refresh(ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void directory_entry::refresh() {
      std::error_code ec;
      refresh(ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()), _path, ec);
      }
    }
#endif

    GHC_INLINE void directory_entry::refresh(std::error_code & ec) noexcept {
#ifdef GHC_OS_WINDOWS
      _status = detail::status_ex(_path, ec, &_symlink_status, &_file_size,
                                  nullptr, &_last_write_time);
#else
      _status = detail::status_ex(_path, ec, &_symlink_status, &_file_size,
                                  &_hard_link_count, &_last_write_time);
#endif
    }

    // 30.10.12.3 directory_entry observers
    GHC_INLINE const filesystem::path & directory_entry::path() const noexcept {
      return _path;
    }

    GHC_INLINE
    directory_entry::operator const filesystem::path &() const noexcept {
      return _path;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::exists() const {
      return filesystem::exists(status());
    }
#endif

    GHC_INLINE bool
    directory_entry::exists(std::error_code & ec) const noexcept {
      return filesystem::exists(status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::is_block_file() const {
      return filesystem::is_block_file(status());
    }
#endif
    GHC_INLINE bool
    directory_entry::is_block_file(std::error_code & ec) const noexcept {
      return filesystem::is_block_file(status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::is_character_file() const {
      return filesystem::is_character_file(status());
    }
#endif

    GHC_INLINE bool
    directory_entry::is_character_file(std::error_code & ec) const noexcept {
      return filesystem::is_character_file(status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::is_directory() const {
      return filesystem::is_directory(status());
    }
#endif

    GHC_INLINE bool
    directory_entry::is_directory(std::error_code & ec) const noexcept {
      return filesystem::is_directory(status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::is_fifo() const {
      return filesystem::is_fifo(status());
    }
#endif

    GHC_INLINE bool
    directory_entry::is_fifo(std::error_code & ec) const noexcept {
      return filesystem::is_fifo(status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::is_other() const {
      return filesystem::is_other(status());
    }
#endif

    GHC_INLINE bool
    directory_entry::is_other(std::error_code & ec) const noexcept {
      return filesystem::is_other(status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::is_regular_file() const {
      return filesystem::is_regular_file(status());
    }
#endif

    GHC_INLINE bool
    directory_entry::is_regular_file(std::error_code & ec) const noexcept {
      return filesystem::is_regular_file(status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::is_socket() const {
      return filesystem::is_socket(status());
    }
#endif

    GHC_INLINE bool
    directory_entry::is_socket(std::error_code & ec) const noexcept {
      return filesystem::is_socket(status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE bool directory_entry::is_symlink() const {
      return filesystem::is_symlink(symlink_status());
    }
#endif

    GHC_INLINE bool
    directory_entry::is_symlink(std::error_code & ec) const noexcept {
      return filesystem::is_symlink(symlink_status(ec));
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE uintmax_t directory_entry::file_size() const {
      if (_status.type() != file_type::none) { return _file_size; }
      return filesystem::file_size(path());
    }
#endif

    GHC_INLINE uintmax_t
    directory_entry::file_size(std::error_code & ec) const noexcept {
      if (_status.type() != file_type::none) {
        ec.clear();
        return _file_size;
      }
      return filesystem::file_size(path(), ec);
    }

#ifndef GHC_OS_WEB
#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE uintmax_t directory_entry::hard_link_count() const {
#ifndef GHC_OS_WINDOWS
      if (_status.type() != file_type::none) { return _hard_link_count; }
#endif
      return filesystem::hard_link_count(path());
    }
#endif

    GHC_INLINE uintmax_t
    directory_entry::hard_link_count(std::error_code & ec) const noexcept {
#ifndef GHC_OS_WINDOWS
      if (_status.type() != file_type::none) {
        ec.clear();
        return _hard_link_count;
      }
#endif
      return filesystem::hard_link_count(path(), ec);
    }
#endif

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE file_time_type directory_entry::last_write_time() const {
      if (_status.type() != file_type::none) {
        return std::chrono::system_clock::from_time_t(_last_write_time);
      }
      return filesystem::last_write_time(path());
    }
#endif

    GHC_INLINE file_time_type
    directory_entry::last_write_time(std::error_code & ec) const noexcept {
      if (_status.type() != file_type::none) {
        ec.clear();
        return std::chrono::system_clock::from_time_t(_last_write_time);
      }
      return filesystem::last_write_time(path(), ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE file_status directory_entry::status() const {
      if (_status.type() != file_type::none) { return _status; }
      return filesystem::status(path());
    }
#endif

    GHC_INLINE file_status
    directory_entry::status(std::error_code & ec) const noexcept {
      if (_status.type() != file_type::none) {
        ec.clear();
        return _status;
      }
      return filesystem::status(path(), ec);
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE file_status directory_entry::symlink_status() const {
      if (_symlink_status.type() != file_type::none) { return _symlink_status; }
      return filesystem::symlink_status(path());
    }
#endif

    GHC_INLINE file_status
    directory_entry::symlink_status(std::error_code & ec) const noexcept {
      if (_symlink_status.type() != file_type::none) {
        ec.clear();
        return _symlink_status;
      }
      return filesystem::symlink_status(path(), ec);
    }

    GHC_INLINE bool
    directory_entry::operator<(const directory_entry & rhs) const noexcept {
      return _path < rhs._path;
    }

    GHC_INLINE bool
    directory_entry::operator==(const directory_entry & rhs) const noexcept {
      return _path == rhs._path;
    }

    GHC_INLINE bool
    directory_entry::operator!=(const directory_entry & rhs) const noexcept {
      return _path != rhs._path;
    }

    GHC_INLINE bool
    directory_entry::operator<=(const directory_entry & rhs) const noexcept {
      return _path <= rhs._path;
    }

    GHC_INLINE bool
    directory_entry::operator>(const directory_entry & rhs) const noexcept {
      return _path > rhs._path;
    }

    GHC_INLINE bool
    directory_entry::operator>=(const directory_entry & rhs) const noexcept {
      return _path >= rhs._path;
    }

    //-----------------------------------------------------------------------------
    // 30.10.13 class directory_iterator

#ifdef GHC_OS_WINDOWS
    class directory_iterator::impl {
    public:
      impl(const path & p, directory_options options)
          : _base(p), _options(options), _dirHandle(INVALID_HANDLE_VALUE) {
        if (!_base.empty()) {
          ZeroMemory(&_findData, sizeof(WIN32_FIND_DATAW));
          if ((_dirHandle = FindFirstFileW(
                   detail::fromUtf8<std::wstring>((_base / "*").u8string())
                       .c_str(),
                   &_findData)) != INVALID_HANDLE_VALUE) {
            if (std::wstring(_findData.cFileName) == L"." ||
                std::wstring(_findData.cFileName) == L"..") {
              increment(_ec);
            } else {
              _current = _base / std::wstring(_findData.cFileName);
              copyToDirEntry(_ec);
            }
          } else {
            auto error = ::GetLastError();
            _base = filesystem::path();
            if (error != ERROR_ACCESS_DENIED ||
                (options & directory_options::skip_permission_denied) ==
                    directory_options::none) {
              _ec = detail::make_system_error();
            }
          }
        }
      }
      impl(const impl & other) = delete;
      ~impl() {
        if (_dirHandle != INVALID_HANDLE_VALUE) {
          FindClose(_dirHandle);
          _dirHandle = INVALID_HANDLE_VALUE;
        }
      }
      void increment(std::error_code & ec) {
        if (_dirHandle != INVALID_HANDLE_VALUE) {
          do {
            if (FindNextFileW(_dirHandle, &_findData)) {
              _current = _base;
#ifdef GHC_RAISE_UNICODE_ERRORS
              try {
                _current.append_name(
                    detail::toUtf8(_findData.cFileName).c_str());
              } catch (filesystem_error & fe) {
                ec = fe.code();
                return;
              }
#else
              _current.append_name(detail::toUtf8(_findData.cFileName).c_str());
#endif
              copyToDirEntry(ec);
            } else {
              auto err = ::GetLastError();
              if (err != ERROR_NO_MORE_FILES) {
                _ec = ec = detail::make_system_error(err);
              }
              FindClose(_dirHandle);
              _dirHandle = INVALID_HANDLE_VALUE;
              _current = filesystem::path();
              break;
            }
          } while (std::wstring(_findData.cFileName) == L"." ||
                   std::wstring(_findData.cFileName) == L"..");
        } else {
          ec = _ec;
        }
      }
      void copyToDirEntry(std::error_code & ec) {
        _dir_entry._path = _current;
        if (_findData.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
          _dir_entry._status = detail::status_ex(
              _current, ec, &_dir_entry._symlink_status, &_dir_entry._file_size,
              nullptr, &_dir_entry._last_write_time);
        } else {
          _dir_entry._status = detail::status_from_INFO(
              _current, &_findData, ec, &_dir_entry._file_size,
              &_dir_entry._last_write_time);
          _dir_entry._symlink_status = _dir_entry._status;
        }
        if (ec) {
          if (_dir_entry._status.type() != file_type::none &&
              _dir_entry._symlink_status.type() != file_type::none) {
            ec.clear();
          } else {
            _dir_entry._file_size = static_cast<uintmax_t>(-1);
            _dir_entry._last_write_time = 0;
          }
        }
      }
      path _base;
      directory_options _options;
      WIN32_FIND_DATAW _findData;
      HANDLE _dirHandle;
      path _current;
      directory_entry _dir_entry;
      std::error_code _ec;
    };
#else
    // POSIX implementation
    class directory_iterator::impl {
    public:
      impl(const path & path, directory_options options)
          : _base(path), _options(options), _dir(nullptr), _entry(nullptr) {
        if (!path.empty()) { _dir = ::opendir(path.native().c_str()); }
        if (!path.empty()) {
          if (!_dir) {
            auto error = errno;
            _base = filesystem::path();
            if (error != EACCES ||
                (options & directory_options::skip_permission_denied) ==
                    directory_options::none) {
              _ec = detail::make_system_error();
            }
          } else {
            increment(_ec);
          }
        }
      }
      impl(const impl & other) = delete;
      ~impl() {
        if (_dir) { ::closedir(_dir); }
      }
      void increment(std::error_code & ec) {
        if (_dir) {
          bool skip;
          do {
            skip = false;
            errno = 0;
            _entry = ::readdir(_dir);
            if (_entry) {
              _current = _base;
              _current.append_name(_entry->d_name);
              _dir_entry = directory_entry(_current, ec);
              if (ec && (ec.value() == EACCES || ec.value() == EPERM) &&
                  (_options & directory_options::skip_permission_denied) ==
                      directory_options::skip_permission_denied) {
                ec.clear();
                skip = true;
              }
            } else {
              ::closedir(_dir);
              _dir = nullptr;
              _current = path();
              if (errno) { ec = detail::make_system_error(); }
              break;
            }
          } while (skip || std::strcmp(_entry->d_name, ".") == 0 ||
                   std::strcmp(_entry->d_name, "..") == 0);
        }
      }
      path _base;
      directory_options _options;
      path _current;
      DIR * _dir;
      struct ::dirent * _entry;
      directory_entry _dir_entry;
      std::error_code _ec;
    };
#endif

    // 30.10.13.1 member functions
    GHC_INLINE directory_iterator::directory_iterator() noexcept
        : _impl(new impl(path(), directory_options::none)) {}

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE directory_iterator::directory_iterator(const path & p)
        : _impl(new impl(p, directory_options::none)) {
      if (_impl->_ec) {
        throw filesystem_error(detail::systemErrorText(_impl->_ec.value()), p,
                               _impl->_ec);
      }
      _impl->_ec.clear();
    }

    GHC_INLINE directory_iterator::directory_iterator(const path & p,
                                                      directory_options options)
        : _impl(new impl(p, options)) {
      if (_impl->_ec) {
        throw filesystem_error(detail::systemErrorText(_impl->_ec.value()), p,
                               _impl->_ec);
      }
    }
#endif

    GHC_INLINE
    directory_iterator::directory_iterator(const path & p,
                                           std::error_code & ec) noexcept
        : _impl(new impl(p, directory_options::none)) {
      if (_impl->_ec) { ec = _impl->_ec; }
    }

    GHC_INLINE
    directory_iterator::directory_iterator(const path & p,
                                           directory_options options,
                                           std::error_code & ec) noexcept
        : _impl(new impl(p, options)) {
      if (_impl->_ec) { ec = _impl->_ec; }
    }

    GHC_INLINE
    directory_iterator::directory_iterator(const directory_iterator & rhs)
        : _impl(rhs._impl) {}

    GHC_INLINE
    directory_iterator::directory_iterator(directory_iterator && rhs) noexcept
        : _impl(std::move(rhs._impl)) {}

    GHC_INLINE directory_iterator::~directory_iterator() {}

    GHC_INLINE directory_iterator &
    directory_iterator::operator=(const directory_iterator & rhs) {
      _impl = rhs._impl;
      return *this;
    }

    GHC_INLINE directory_iterator &
    directory_iterator::operator=(directory_iterator && rhs) noexcept {
      _impl = std::move(rhs._impl);
      return *this;
    }

    GHC_INLINE const directory_entry & directory_iterator::operator*() const {
      return _impl->_dir_entry;
    }

    GHC_INLINE const directory_entry * directory_iterator::operator->() const {
      return &_impl->_dir_entry;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE directory_iterator & directory_iterator::operator++() {
      std::error_code ec;
      _impl->increment(ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()),
                               _impl->_current, ec);
      }
      return *this;
    }
#endif

    GHC_INLINE directory_iterator &
    directory_iterator::increment(std::error_code & ec) noexcept {
      _impl->increment(ec);
      return *this;
    }

    GHC_INLINE bool
    directory_iterator::operator==(const directory_iterator & rhs) const {
      return _impl->_current == rhs._impl->_current;
    }

    GHC_INLINE bool
    directory_iterator::operator!=(const directory_iterator & rhs) const {
      return _impl->_current != rhs._impl->_current;
    }

    // 30.10.13.2 directory_iterator non-member functions

    GHC_INLINE directory_iterator begin(directory_iterator iter) noexcept {
      return iter;
    }

    GHC_INLINE directory_iterator end(const directory_iterator &) noexcept {
      return directory_iterator();
    }

    //-----------------------------------------------------------------------------
    // 30.10.14 class recursive_directory_iterator

    GHC_INLINE
    recursive_directory_iterator::recursive_directory_iterator() noexcept
        : _impl(new recursive_directory_iterator_impl(directory_options::none,
                                                      true)) {
      _impl->_dir_iter_stack.push(directory_iterator());
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE
    recursive_directory_iterator::recursive_directory_iterator(const path & p)
        : _impl(new recursive_directory_iterator_impl(directory_options::none,
                                                      true)) {
      _impl->_dir_iter_stack.push(directory_iterator(p));
    }

    GHC_INLINE recursive_directory_iterator::recursive_directory_iterator(
        const path & p, directory_options options)
        : _impl(new recursive_directory_iterator_impl(options, true)) {
      _impl->_dir_iter_stack.push(directory_iterator(p, options));
    }
#endif

    GHC_INLINE recursive_directory_iterator::recursive_directory_iterator(
        const path & p, directory_options options,
        std::error_code & ec) noexcept
        : _impl(new recursive_directory_iterator_impl(options, true)) {
      _impl->_dir_iter_stack.push(directory_iterator(p, options, ec));
    }

    GHC_INLINE recursive_directory_iterator::recursive_directory_iterator(
        const path & p, std::error_code & ec) noexcept
        : _impl(new recursive_directory_iterator_impl(directory_options::none,
                                                      true)) {
      _impl->_dir_iter_stack.push(directory_iterator(p, ec));
    }

    GHC_INLINE recursive_directory_iterator::recursive_directory_iterator(
        const recursive_directory_iterator & rhs)
        : _impl(rhs._impl) {}

    GHC_INLINE recursive_directory_iterator::recursive_directory_iterator(
        recursive_directory_iterator && rhs) noexcept
        : _impl(std::move(rhs._impl)) {}

    GHC_INLINE recursive_directory_iterator::~recursive_directory_iterator() {}

    // 30.10.14.1 observers
    GHC_INLINE directory_options recursive_directory_iterator::options() const {
      return _impl->_options;
    }

    GHC_INLINE int recursive_directory_iterator::depth() const {
      return static_cast<int>(_impl->_dir_iter_stack.size() - 1);
    }

    GHC_INLINE bool recursive_directory_iterator::recursion_pending() const {
      return _impl->_recursion_pending;
    }

    GHC_INLINE const directory_entry &
    recursive_directory_iterator::operator*() const {
      return *(_impl->_dir_iter_stack.top());
    }

    GHC_INLINE const directory_entry *
    recursive_directory_iterator::operator->() const {
      return &(*(_impl->_dir_iter_stack.top()));
    }

    // 30.10.14.1 modifiers recursive_directory_iterator&
    GHC_INLINE recursive_directory_iterator &
    recursive_directory_iterator::operator=(
        const recursive_directory_iterator & rhs) {
      _impl = rhs._impl;
      return *this;
    }

    GHC_INLINE recursive_directory_iterator &
    recursive_directory_iterator::operator=(
        recursive_directory_iterator && rhs) noexcept {
      _impl = std::move(rhs._impl);
      return *this;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE recursive_directory_iterator &
    recursive_directory_iterator::operator++() {
      std::error_code ec;
      increment(ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()),
                               _impl->_dir_iter_stack.empty()
                                   ? path()
                                   : _impl->_dir_iter_stack.top()->path(),
                               ec);
      }
      return *this;
    }
#endif

    GHC_INLINE recursive_directory_iterator &
    recursive_directory_iterator::increment(std::error_code & ec) noexcept {
      auto status = (*this)->status(ec);
      if (ec) return *this;
      auto symlink_status = (*this)->symlink_status(ec);
      if (ec) return *this;
      if (recursion_pending() && is_directory(status) &&
          (!is_symlink(symlink_status) ||
           (options() & directory_options::follow_directory_symlink) !=
               directory_options::none)) {
        _impl->_dir_iter_stack.push(
            directory_iterator((*this)->path(), _impl->_options, ec));
      } else {
        _impl->_dir_iter_stack.top().increment(ec);
      }
      if (!ec) {
        while (depth() &&
               _impl->_dir_iter_stack.top() == directory_iterator()) {
          _impl->_dir_iter_stack.pop();
          _impl->_dir_iter_stack.top().increment(ec);
        }
      } else if (!_impl->_dir_iter_stack.empty()) {
        _impl->_dir_iter_stack.pop();
      }
      _impl->_recursion_pending = true;
      return *this;
    }

#ifdef GHC_WITH_EXCEPTIONS
    GHC_INLINE void recursive_directory_iterator::pop() {
      std::error_code ec;
      pop(ec);
      if (ec) {
        throw filesystem_error(detail::systemErrorText(ec.value()),
                               _impl->_dir_iter_stack.empty()
                                   ? path()
                                   : _impl->_dir_iter_stack.top()->path(),
                               ec);
      }
    }
#endif

    GHC_INLINE void recursive_directory_iterator::pop(std::error_code & ec) {
      if (depth() == 0) {
        *this = recursive_directory_iterator();
      } else {
        do {
          _impl->_dir_iter_stack.pop();
          _impl->_dir_iter_stack.top().increment(ec);
        } while (depth() &&
                 _impl->_dir_iter_stack.top() == directory_iterator());
      }
    }

    GHC_INLINE void recursive_directory_iterator::disable_recursion_pending() {
      _impl->_recursion_pending = false;
    }

    // other members as required by 27.2.3, input iterators
    GHC_INLINE bool recursive_directory_iterator::operator==(
        const recursive_directory_iterator & rhs) const {
      return _impl->_dir_iter_stack.top() == rhs._impl->_dir_iter_stack.top();
    }

    GHC_INLINE bool recursive_directory_iterator::operator!=(
        const recursive_directory_iterator & rhs) const {
      return _impl->_dir_iter_stack.top() != rhs._impl->_dir_iter_stack.top();
    }

    // 30.10.14.2 directory_iterator non-member functions
    GHC_INLINE recursive_directory_iterator
    begin(recursive_directory_iterator iter) noexcept {
      return iter;
    }

    GHC_INLINE recursive_directory_iterator
    end(const recursive_directory_iterator &) noexcept {
      return recursive_directory_iterator();
    }

#endif // GHC_EXPAND_IMPL

  } // namespace filesystem
} // namespace ghc

// cleanup some macros
#undef GHC_INLINE
#undef GHC_EXPAND_IMPL

#endif // GHC_FILESYSTEM_H