1 // Locale support -*- C++ -*-
3 // Copyright (C) 1997-2023 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
25 /** @file bits/locale_classes.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{locale}
31 // ISO C++ 14882: 22.1 Locales
34 #ifndef _LOCALE_CLASSES_H
35 #define _LOCALE_CLASSES_H 1
37 #pragma GCC system_header
39 #include <bits/localefwd.h>
41 #include <ext/atomicity.h>
43 namespace std
_GLIBCXX_VISIBILITY(default)
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
47 // 22.1.1 Class locale
49 * @brief Container class for localization functionality.
52 * The locale class is first a class wrapper for C library locales. It is
53 * also an extensible container for user-defined localization. A locale is
54 * a collection of facets that implement various localization features such
55 * as money, time, and number printing.
57 * Constructing C++ locales does not change the C library locale.
59 * This library supports efficient construction and copying of locales
60 * through a reference counting implementation of the locale class.
66 /// Definition of locale::category.
69 // Forward decls and friends:
77 template<typename _Facet
>
79 has_facet(const locale
&) throw();
81 template<typename _Facet
>
83 use_facet(const locale
&);
85 template<typename _Facet
>
87 __try_use_facet(const locale
&) _GLIBCXX_NOTHROW
;
89 template<typename _Cache
>
90 friend struct __use_cache
;
94 * @brief Category values.
96 * The standard category values are none, ctype, numeric, collate, time,
97 * monetary, and messages. They form a bitmask that supports union and
98 * intersection. The category all is the union of these values.
100 * NB: Order must match _S_facet_categories definition in locale.cc
102 static const category none
= 0;
103 static const category ctype
= 1L << 0;
104 static const category numeric
= 1L << 1;
105 static const category collate
= 1L << 2;
106 static const category time
= 1L << 3;
107 static const category monetary
= 1L << 4;
108 static const category messages
= 1L << 5;
109 static const category all
= (ctype
| numeric
| collate
|
110 time
| monetary
| messages
);
113 // Construct/copy/destroy:
116 * @brief Default constructor.
118 * Constructs a copy of the global locale. If no locale has been
119 * explicitly set, this is the C locale.
124 * @brief Copy constructor.
126 * Constructs a copy of @a other.
128 * @param __other The locale to copy.
130 locale(const locale
& __other
) throw();
133 * @brief Named locale constructor.
135 * Constructs a copy of the named C library locale.
137 * @param __s Name of the locale to construct.
138 * @throw std::runtime_error if __s is null or an undefined locale.
141 locale(const char* __s
);
144 * @brief Construct locale with facets from another locale.
146 * Constructs a copy of the locale @a base. The facets specified by @a
147 * cat are replaced with those from the locale named by @a s. If base is
148 * named, this locale instance will also be named.
150 * @param __base The locale to copy.
151 * @param __s Name of the locale to use facets from.
152 * @param __cat Set of categories defining the facets to use from __s.
153 * @throw std::runtime_error if __s is null or an undefined locale.
155 locale(const locale
& __base
, const char* __s
, category __cat
);
157 #if __cplusplus >= 201103L
159 * @brief Named locale constructor.
161 * Constructs a copy of the named C library locale.
163 * @param __s Name of the locale to construct.
164 * @throw std::runtime_error if __s is an undefined locale.
167 locale(const std::string
& __s
) : locale(__s
.c_str()) { }
170 * @brief Construct locale with facets from another locale.
172 * Constructs a copy of the locale @a base. The facets specified by @a
173 * cat are replaced with those from the locale named by @a s. If base is
174 * named, this locale instance will also be named.
176 * @param __base The locale to copy.
177 * @param __s Name of the locale to use facets from.
178 * @param __cat Set of categories defining the facets to use from __s.
179 * @throw std::runtime_error if __s is an undefined locale.
181 locale(const locale
& __base
, const std::string
& __s
, category __cat
)
182 : locale(__base
, __s
.c_str(), __cat
) { }
186 * @brief Construct locale with facets from another locale.
188 * Constructs a copy of the locale @a base. The facets specified by @a
189 * cat are replaced with those from the locale @a add. If @a base and @a
190 * add are named, this locale instance will also be named.
192 * @param __base The locale to copy.
193 * @param __add The locale to use facets from.
194 * @param __cat Set of categories defining the facets to use from add.
196 locale(const locale
& __base
, const locale
& __add
, category __cat
);
199 * @brief Construct locale with another facet.
201 * Constructs a copy of the locale @a __other. The facet @a __f
202 * is added to @a __other, replacing an existing facet of type
203 * Facet if there is one. If @a __f is null, this locale is a
204 * copy of @a __other.
206 * @param __other The locale to copy.
207 * @param __f The facet to add in.
209 template<typename _Facet
>
210 locale(const locale
& __other
, _Facet
* __f
);
212 /// Locale destructor.
216 * @brief Assignment operator.
218 * Set this locale to be a copy of @a other.
220 * @param __other The locale to copy.
221 * @return A reference to this locale.
224 operator=(const locale
& __other
) throw();
227 * @brief Construct locale with another facet.
229 * Constructs and returns a new copy of this locale. Adds or replaces an
230 * existing facet of type Facet from the locale @a other into the new
233 * @tparam _Facet The facet type to copy from other
234 * @param __other The locale to copy from.
235 * @return Newly constructed locale.
236 * @throw std::runtime_error if __other has no facet of type _Facet.
238 template<typename _Facet
>
240 combine(const locale
& __other
) const;
242 // Locale operations:
244 * @brief Return locale name.
245 * @return Locale name or "*" if unnamed.
247 _GLIBCXX_DEFAULT_ABI_TAG
252 * @brief Locale equality.
254 * @param __other The locale to compare against.
255 * @return True if other and this refer to the same locale instance, are
256 * copies, or have the same name. False otherwise.
259 operator==(const locale
& __other
) const throw();
261 #if __cpp_impl_three_way_comparison < 201907L
263 * @brief Locale inequality.
265 * @param __other The locale to compare against.
266 * @return ! (*this == __other)
269 operator!=(const locale
& __other
) const throw()
270 { return !(this->operator==(__other
)); }
274 * @brief Compare two strings according to collate.
276 * Template operator to compare two strings using the compare function of
277 * the collate facet in this locale. One use is to provide the locale to
278 * the sort function. For example, a vector v of strings could be sorted
279 * according to locale loc by doing:
281 * std::sort(v.begin(), v.end(), loc);
284 * @param __s1 First string to compare.
285 * @param __s2 Second string to compare.
286 * @return True if collate<_Char> facet compares __s1 < __s2, else false.
288 template<typename _Char
, typename _Traits
, typename _Alloc
>
290 operator()(const basic_string
<_Char
, _Traits
, _Alloc
>& __s1
,
291 const basic_string
<_Char
, _Traits
, _Alloc
>& __s2
) const;
293 // Global locale objects:
295 * @brief Set global locale
297 * This function sets the global locale to the argument and returns a
298 * copy of the previous global locale. If the argument has a name, it
299 * will also call std::setlocale(LC_ALL, loc.name()).
301 * @param __loc The new locale to make global.
302 * @return Copy of the old global locale.
305 global(const locale
& __loc
);
308 * @brief Return reference to the C locale.
314 // The (shared) implementation
317 // The "C" reference locale
318 static _Impl
* _S_classic
;
320 // Current global locale
321 static _Impl
* _S_global
;
323 // Names of underlying locale categories.
324 // NB: locale::global() has to know how to modify all the
325 // underlying categories, not just the ones required by the C++
327 static const char* const* const _S_categories
;
329 // Number of standard categories. For C++, these categories are
330 // collate, ctype, monetary, numeric, time, and messages. These
331 // directly correspond to ISO C99 macros LC_COLLATE, LC_CTYPE,
332 // LC_MONETARY, LC_NUMERIC, and LC_TIME. In addition, POSIX (IEEE
333 // 1003.1-2001) specifies LC_MESSAGES.
334 // In addition to the standard categories, the underlying
335 // operating system is allowed to define extra LC_*
336 // macros. For GNU systems, the following are also valid:
337 // LC_PAPER, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_MEASUREMENT,
338 // and LC_IDENTIFICATION.
339 enum { _S_categories_size
= 6 + _GLIBCXX_NUM_CATEGORIES
};
342 static __gthread_once_t _S_once
;
346 locale(_Impl
*) throw();
352 _S_initialize_once() throw();
355 _S_normalize_category(category
);
358 _M_coalesce(const locale
& __base
, const locale
& __add
, category __cat
);
360 #if _GLIBCXX_USE_CXX11_ABI
361 static const id
* const _S_twinned_facets
[];
366 // 22.1.1.1.2 Class locale::facet
368 * @brief Localization functionality base class.
371 * The facet class is the base class for a localization feature, such as
372 * money, time, and number printing. It provides common support for facets
373 * and reference management.
375 * Facets may not be copied or assigned.
381 friend class locale::_Impl
;
383 mutable _Atomic_word _M_refcount
;
385 // Contains data from the underlying "C" library for the classic locale.
386 static __c_locale _S_c_locale
;
388 // String literal for the name of the classic locale.
389 static const char _S_c_name
[2];
392 static __gthread_once_t _S_once
;
396 _S_initialize_once();
400 * @brief Facet constructor.
402 * This is the constructor provided by the standard. If refs is 0, the
403 * facet is destroyed when the last referencing locale is destroyed.
404 * Otherwise the facet will never be destroyed.
406 * @param __refs The initial value for reference count.
409 facet(size_t __refs
= 0) throw() : _M_refcount(__refs
? 1 : 0)
412 /// Facet destructor.
417 _S_create_c_locale(__c_locale
& __cloc
, const char* __s
,
418 __c_locale __old
= 0);
421 _S_clone_c_locale(__c_locale
& __cloc
) throw();
424 _S_destroy_c_locale(__c_locale
& __cloc
);
427 _S_lc_ctype_c_locale(__c_locale __cloc
, const char* __s
);
429 // Returns data from the underlying "C" library data for the
434 _GLIBCXX_CONST
static const char*
435 _S_get_c_name() throw();
437 #if __cplusplus < 201103L
439 facet(const facet
&); // Not defined.
442 operator=(const facet
&); // Not defined.
444 facet(const facet
&) = delete;
447 operator=(const facet
&) = delete;
452 _M_add_reference() const throw()
453 { __gnu_cxx::__atomic_add_dispatch(&_M_refcount
, 1); }
456 _M_remove_reference() const throw()
458 // Be race-detector-friendly. For more info see bits/c++config.
459 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount
);
460 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount
, -1) == 1)
462 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount
);
470 const facet
* _M_sso_shim(const id
*) const;
471 const facet
* _M_cow_shim(const id
*) const;
474 class __shim
; // For internal use only.
478 // 22.1.1.1.3 Class locale::id
480 * @brief Facet ID class.
483 * The ID class provides facets with an index used to identify them.
484 * Every facet class must define a public static member locale::id, or be
485 * derived from a facet that provides this member, otherwise the facet
486 * cannot be used in a locale. The locale::id ensures that each class
487 * type gets a unique identifier.
493 friend class locale::_Impl
;
495 template<typename _Facet
>
497 use_facet(const locale
&);
499 template<typename _Facet
>
501 has_facet(const locale
&) throw();
503 template<typename _Facet
>
505 __try_use_facet(const locale
&) _GLIBCXX_NOTHROW
;
507 // NB: There is no accessor for _M_index because it may be used
508 // before the constructor is run; the effect of calling a member
509 // function (even an inline) would be undefined.
510 mutable size_t _M_index
;
512 // Last id number assigned.
513 static _Atomic_word _S_refcount
;
516 operator=(const id
&); // Not defined.
518 id(const id
&); // Not defined.
521 // NB: This class is always a static data member, and thus can be
522 // counted on to be zero-initialized.
527 _M_id() const throw();
531 // Implementation object for locale.
537 friend class locale::facet
;
539 template<typename _Facet
>
541 has_facet(const locale
&) throw();
543 template<typename _Facet
>
545 use_facet(const locale
&);
547 template<typename _Facet
>
549 __try_use_facet(const locale
&) _GLIBCXX_NOTHROW
;
551 template<typename _Cache
>
552 friend struct __use_cache
;
556 _Atomic_word _M_refcount
;
557 const facet
** _M_facets
;
558 size_t _M_facets_size
;
559 const facet
** _M_caches
;
561 static const locale::id
* const _S_id_ctype
[];
562 static const locale::id
* const _S_id_numeric
[];
563 static const locale::id
* const _S_id_collate
[];
564 static const locale::id
* const _S_id_time
[];
565 static const locale::id
* const _S_id_monetary
[];
566 static const locale::id
* const _S_id_messages
[];
567 static const locale::id
* const* const _S_facet_categories
[];
570 _M_add_reference() throw()
571 { __gnu_cxx::__atomic_add_dispatch(&_M_refcount
, 1); }
574 _M_remove_reference() throw()
576 // Be race-detector-friendly. For more info see bits/c++config.
577 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount
);
578 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount
, -1) == 1)
580 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount
);
588 _Impl(const _Impl
&, size_t);
589 _Impl(const char*, size_t);
590 _Impl(size_t) throw();
594 _Impl(const _Impl
&); // Not defined.
597 operator=(const _Impl
&); // Not defined.
604 // We must actually compare all the _M_names: can be all equal!
605 for (size_t __i
= 0; __ret
&& __i
< _S_categories_size
- 1; ++__i
)
606 __ret
= __builtin_strcmp(_M_names
[__i
], _M_names
[__i
+ 1]) == 0;
611 _M_replace_categories(const _Impl
*, category
);
614 _M_replace_category(const _Impl
*, const locale::id
* const*);
617 _M_replace_facet(const _Impl
*, const locale::id
*);
620 _M_install_facet(const locale::id
*, const facet
*);
622 template<typename _Facet
>
624 _M_init_facet(_Facet
* __facet
)
625 { _M_install_facet(&_Facet::id
, __facet
); }
627 template<typename _Facet
>
629 _M_init_facet_unchecked(_Facet
* __facet
)
631 __facet
->_M_add_reference();
632 _M_facets
[_Facet::id
._M_id()] = __facet
;
636 _M_install_cache(const facet
*, size_t);
638 void _M_init_extra(facet
**);
639 void _M_init_extra(void*, void*, const char*, const char*);
641 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
642 void _M_init_extra_ldbl128(bool);
648 * @brief Facet for localized string comparison.
650 * This facet encapsulates the code to compare strings in a localized
653 * The collate template uses protected virtual functions to provide
654 * the actual results. The public accessors forward the call to
655 * the virtual functions. These virtual functions are hooks for
656 * developers to implement the behavior they require from the
659 template<typename _CharT
>
660 class _GLIBCXX_NAMESPACE_CXX11 collate
: public locale::facet
666 typedef _CharT char_type
;
667 typedef basic_string
<_CharT
> string_type
;
671 // Underlying "C" library locale information saved from
672 // initialization, needed by collate_byname as well.
673 __c_locale _M_c_locale_collate
;
676 /// Numpunct facet id.
677 static locale::id id
;
680 * @brief Constructor performs initialization.
682 * This is the constructor provided by the standard.
684 * @param __refs Passed to the base facet class.
687 collate(size_t __refs
= 0)
688 : facet(__refs
), _M_c_locale_collate(_S_get_c_locale())
692 * @brief Internal constructor. Not for general use.
694 * This is a constructor for use by the library itself to set up new
697 * @param __cloc The C locale.
698 * @param __refs Passed to the base facet class.
701 collate(__c_locale __cloc
, size_t __refs
= 0)
702 : facet(__refs
), _M_c_locale_collate(_S_clone_c_locale(__cloc
))
706 * @brief Compare two strings.
708 * This function compares two strings and returns the result by calling
709 * collate::do_compare().
711 * @param __lo1 Start of string 1.
712 * @param __hi1 End of string 1.
713 * @param __lo2 Start of string 2.
714 * @param __hi2 End of string 2.
715 * @return 1 if string1 > string2, -1 if string1 < string2, else 0.
718 compare(const _CharT
* __lo1
, const _CharT
* __hi1
,
719 const _CharT
* __lo2
, const _CharT
* __hi2
) const
720 { return this->do_compare(__lo1
, __hi1
, __lo2
, __hi2
); }
723 * @brief Transform string to comparable form.
725 * This function is a wrapper for strxfrm functionality. It takes the
726 * input string and returns a modified string that can be directly
727 * compared to other transformed strings. In the C locale, this
728 * function just returns a copy of the input string. In some other
729 * locales, it may replace two chars with one, change a char for
730 * another, etc. It does so by returning collate::do_transform().
732 * @param __lo Start of string.
733 * @param __hi End of string.
734 * @return Transformed string_type.
737 transform(const _CharT
* __lo
, const _CharT
* __hi
) const
738 { return this->do_transform(__lo
, __hi
); }
741 * @brief Return hash of a string.
743 * This function computes and returns a hash on the input string. It
744 * does so by returning collate::do_hash().
746 * @param __lo Start of string.
747 * @param __hi End of string.
748 * @return Hash value.
751 hash(const _CharT
* __lo
, const _CharT
* __hi
) const
752 { return this->do_hash(__lo
, __hi
); }
754 // Used to abstract out _CharT bits in virtual member functions, below.
756 _M_compare(const _CharT
*, const _CharT
*) const throw();
759 _M_transform(_CharT
*, const _CharT
*, size_t) const throw();
765 { _S_destroy_c_locale(_M_c_locale_collate
); }
768 * @brief Compare two strings.
770 * This function is a hook for derived classes to change the value
771 * returned. @see compare().
773 * @param __lo1 Start of string 1.
774 * @param __hi1 End of string 1.
775 * @param __lo2 Start of string 2.
776 * @param __hi2 End of string 2.
777 * @return 1 if string1 > string2, -1 if string1 < string2, else 0.
780 do_compare(const _CharT
* __lo1
, const _CharT
* __hi1
,
781 const _CharT
* __lo2
, const _CharT
* __hi2
) const;
784 * @brief Transform string to comparable form.
786 * This function is a hook for derived classes to change the value
791 * @return transformed string.
794 do_transform(const _CharT
* __lo
, const _CharT
* __hi
) const;
797 * @brief Return hash of a string.
799 * This function computes and returns a hash on the input string. This
800 * function is a hook for derived classes to change the value returned.
802 * @param __lo Start of string.
803 * @param __hi End of string.
804 * @return Hash value.
807 do_hash(const _CharT
* __lo
, const _CharT
* __hi
) const;
810 template<typename _CharT
>
811 locale::id collate
<_CharT
>::id
;
816 collate
<char>::_M_compare(const char*, const char*) const throw();
820 collate
<char>::_M_transform(char*, const char*, size_t) const throw();
822 #ifdef _GLIBCXX_USE_WCHAR_T
825 collate
<wchar_t>::_M_compare(const wchar_t*, const wchar_t*) const throw();
829 collate
<wchar_t>::_M_transform(wchar_t*, const wchar_t*, size_t) const throw();
832 /// class collate_byname [22.2.4.2].
833 template<typename _CharT
>
834 class _GLIBCXX_NAMESPACE_CXX11 collate_byname
: public collate
<_CharT
>
839 typedef _CharT char_type
;
840 typedef basic_string
<_CharT
> string_type
;
844 collate_byname(const char* __s
, size_t __refs
= 0)
845 : collate
<_CharT
>(__refs
)
847 if (__builtin_strcmp(__s
, "C") != 0
848 && __builtin_strcmp(__s
, "POSIX") != 0)
850 this->_S_destroy_c_locale(this->_M_c_locale_collate
);
851 this->_S_create_c_locale(this->_M_c_locale_collate
, __s
);
855 #if __cplusplus >= 201103L
857 collate_byname(const string
& __s
, size_t __refs
= 0)
858 : collate_byname(__s
.c_str(), __refs
) { }
863 ~collate_byname() { }
866 _GLIBCXX_END_NAMESPACE_VERSION
869 # include <bits/locale_classes.tcc>