1 // Locale support -*- C++ -*-
3 // Copyright (C) 1997-2021 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 _Cache
>
86 friend struct __use_cache
;
90 * @brief Category values.
92 * The standard category values are none, ctype, numeric, collate, time,
93 * monetary, and messages. They form a bitmask that supports union and
94 * intersection. The category all is the union of these values.
96 * NB: Order must match _S_facet_categories definition in locale.cc
98 static const category none
= 0;
99 static const category ctype
= 1L << 0;
100 static const category numeric
= 1L << 1;
101 static const category collate
= 1L << 2;
102 static const category time
= 1L << 3;
103 static const category monetary
= 1L << 4;
104 static const category messages
= 1L << 5;
105 static const category all
= (ctype
| numeric
| collate
|
106 time
| monetary
| messages
);
109 // Construct/copy/destroy:
112 * @brief Default constructor.
114 * Constructs a copy of the global locale. If no locale has been
115 * explicitly set, this is the C locale.
120 * @brief Copy constructor.
122 * Constructs a copy of @a other.
124 * @param __other The locale to copy.
126 locale(const locale
& __other
) throw();
129 * @brief Named locale constructor.
131 * Constructs a copy of the named C library locale.
133 * @param __s Name of the locale to construct.
134 * @throw std::runtime_error if __s is null or an undefined locale.
137 locale(const char* __s
);
140 * @brief Construct locale with facets from another locale.
142 * Constructs a copy of the locale @a base. The facets specified by @a
143 * cat are replaced with those from the locale named by @a s. If base is
144 * named, this locale instance will also be named.
146 * @param __base The locale to copy.
147 * @param __s Name of the locale to use facets from.
148 * @param __cat Set of categories defining the facets to use from __s.
149 * @throw std::runtime_error if __s is null or an undefined locale.
151 locale(const locale
& __base
, const char* __s
, category __cat
);
153 #if __cplusplus >= 201103L
155 * @brief Named locale constructor.
157 * Constructs a copy of the named C library locale.
159 * @param __s Name of the locale to construct.
160 * @throw std::runtime_error if __s is an undefined locale.
163 locale(const std::string
& __s
) : locale(__s
.c_str()) { }
166 * @brief Construct locale with facets from another locale.
168 * Constructs a copy of the locale @a base. The facets specified by @a
169 * cat are replaced with those from the locale named by @a s. If base is
170 * named, this locale instance will also be named.
172 * @param __base The locale to copy.
173 * @param __s Name of the locale to use facets from.
174 * @param __cat Set of categories defining the facets to use from __s.
175 * @throw std::runtime_error if __s is an undefined locale.
177 locale(const locale
& __base
, const std::string
& __s
, category __cat
)
178 : locale(__base
, __s
.c_str(), __cat
) { }
182 * @brief Construct locale with facets from another locale.
184 * Constructs a copy of the locale @a base. The facets specified by @a
185 * cat are replaced with those from the locale @a add. If @a base and @a
186 * add are named, this locale instance will also be named.
188 * @param __base The locale to copy.
189 * @param __add The locale to use facets from.
190 * @param __cat Set of categories defining the facets to use from add.
192 locale(const locale
& __base
, const locale
& __add
, category __cat
);
195 * @brief Construct locale with another facet.
197 * Constructs a copy of the locale @a __other. The facet @a __f
198 * is added to @a __other, replacing an existing facet of type
199 * Facet if there is one. If @a __f is null, this locale is a
200 * copy of @a __other.
202 * @param __other The locale to copy.
203 * @param __f The facet to add in.
205 template<typename _Facet
>
206 locale(const locale
& __other
, _Facet
* __f
);
208 /// Locale destructor.
212 * @brief Assignment operator.
214 * Set this locale to be a copy of @a other.
216 * @param __other The locale to copy.
217 * @return A reference to this locale.
220 operator=(const locale
& __other
) throw();
223 * @brief Construct locale with another facet.
225 * Constructs and returns a new copy of this locale. Adds or replaces an
226 * existing facet of type Facet from the locale @a other into the new
229 * @tparam _Facet The facet type to copy from other
230 * @param __other The locale to copy from.
231 * @return Newly constructed locale.
232 * @throw std::runtime_error if __other has no facet of type _Facet.
234 template<typename _Facet
>
236 combine(const locale
& __other
) const;
238 // Locale operations:
240 * @brief Return locale name.
241 * @return Locale name or "*" if unnamed.
243 _GLIBCXX_DEFAULT_ABI_TAG
248 * @brief Locale equality.
250 * @param __other The locale to compare against.
251 * @return True if other and this refer to the same locale instance, are
252 * copies, or have the same name. False otherwise.
255 operator==(const locale
& __other
) const throw();
257 #if __cpp_impl_three_way_comparison < 201907L
259 * @brief Locale inequality.
261 * @param __other The locale to compare against.
262 * @return ! (*this == __other)
265 operator!=(const locale
& __other
) const throw()
266 { return !(this->operator==(__other
)); }
270 * @brief Compare two strings according to collate.
272 * Template operator to compare two strings using the compare function of
273 * the collate facet in this locale. One use is to provide the locale to
274 * the sort function. For example, a vector v of strings could be sorted
275 * according to locale loc by doing:
277 * std::sort(v.begin(), v.end(), loc);
280 * @param __s1 First string to compare.
281 * @param __s2 Second string to compare.
282 * @return True if collate<_Char> facet compares __s1 < __s2, else false.
284 template<typename _Char
, typename _Traits
, typename _Alloc
>
286 operator()(const basic_string
<_Char
, _Traits
, _Alloc
>& __s1
,
287 const basic_string
<_Char
, _Traits
, _Alloc
>& __s2
) const;
289 // Global locale objects:
291 * @brief Set global locale
293 * This function sets the global locale to the argument and returns a
294 * copy of the previous global locale. If the argument has a name, it
295 * will also call std::setlocale(LC_ALL, loc.name()).
297 * @param __loc The new locale to make global.
298 * @return Copy of the old global locale.
301 global(const locale
& __loc
);
304 * @brief Return reference to the C locale.
310 // The (shared) implementation
313 // The "C" reference locale
314 static _Impl
* _S_classic
;
316 // Current global locale
317 static _Impl
* _S_global
;
319 // Names of underlying locale categories.
320 // NB: locale::global() has to know how to modify all the
321 // underlying categories, not just the ones required by the C++
323 static const char* const* const _S_categories
;
325 // Number of standard categories. For C++, these categories are
326 // collate, ctype, monetary, numeric, time, and messages. These
327 // directly correspond to ISO C99 macros LC_COLLATE, LC_CTYPE,
328 // LC_MONETARY, LC_NUMERIC, and LC_TIME. In addition, POSIX (IEEE
329 // 1003.1-2001) specifies LC_MESSAGES.
330 // In addition to the standard categories, the underlying
331 // operating system is allowed to define extra LC_*
332 // macros. For GNU systems, the following are also valid:
333 // LC_PAPER, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_MEASUREMENT,
334 // and LC_IDENTIFICATION.
335 enum { _S_categories_size
= 6 + _GLIBCXX_NUM_CATEGORIES
};
338 static __gthread_once_t _S_once
;
342 locale(_Impl
*) throw();
348 _S_initialize_once() throw();
351 _S_normalize_category(category
);
354 _M_coalesce(const locale
& __base
, const locale
& __add
, category __cat
);
356 #if _GLIBCXX_USE_CXX11_ABI
357 static const id
* const _S_twinned_facets
[];
362 // 22.1.1.1.2 Class locale::facet
364 * @brief Localization functionality base class.
367 * The facet class is the base class for a localization feature, such as
368 * money, time, and number printing. It provides common support for facets
369 * and reference management.
371 * Facets may not be copied or assigned.
377 friend class locale::_Impl
;
379 mutable _Atomic_word _M_refcount
;
381 // Contains data from the underlying "C" library for the classic locale.
382 static __c_locale _S_c_locale
;
384 // String literal for the name of the classic locale.
385 static const char _S_c_name
[2];
388 static __gthread_once_t _S_once
;
392 _S_initialize_once();
396 * @brief Facet constructor.
398 * This is the constructor provided by the standard. If refs is 0, the
399 * facet is destroyed when the last referencing locale is destroyed.
400 * Otherwise the facet will never be destroyed.
402 * @param __refs The initial value for reference count.
405 facet(size_t __refs
= 0) throw() : _M_refcount(__refs
? 1 : 0)
408 /// Facet destructor.
413 _S_create_c_locale(__c_locale
& __cloc
, const char* __s
,
414 __c_locale __old
= 0);
417 _S_clone_c_locale(__c_locale
& __cloc
) throw();
420 _S_destroy_c_locale(__c_locale
& __cloc
);
423 _S_lc_ctype_c_locale(__c_locale __cloc
, const char* __s
);
425 // Returns data from the underlying "C" library data for the
430 _GLIBCXX_CONST
static const char*
431 _S_get_c_name() throw();
433 #if __cplusplus < 201103L
435 facet(const facet
&); // Not defined.
438 operator=(const facet
&); // Not defined.
440 facet(const facet
&) = delete;
443 operator=(const facet
&) = delete;
448 _M_add_reference() const throw()
449 { __gnu_cxx::__atomic_add_dispatch(&_M_refcount
, 1); }
452 _M_remove_reference() const throw()
454 // Be race-detector-friendly. For more info see bits/c++config.
455 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount
);
456 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount
, -1) == 1)
458 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount
);
466 const facet
* _M_sso_shim(const id
*) const;
467 const facet
* _M_cow_shim(const id
*) const;
470 class __shim
; // For internal use only.
474 // 22.1.1.1.3 Class locale::id
476 * @brief Facet ID class.
479 * The ID class provides facets with an index used to identify them.
480 * Every facet class must define a public static member locale::id, or be
481 * derived from a facet that provides this member, otherwise the facet
482 * cannot be used in a locale. The locale::id ensures that each class
483 * type gets a unique identifier.
489 friend class locale::_Impl
;
491 template<typename _Facet
>
493 use_facet(const locale
&);
495 template<typename _Facet
>
497 has_facet(const locale
&) throw();
499 // NB: There is no accessor for _M_index because it may be used
500 // before the constructor is run; the effect of calling a member
501 // function (even an inline) would be undefined.
502 mutable size_t _M_index
;
504 // Last id number assigned.
505 static _Atomic_word _S_refcount
;
508 operator=(const id
&); // Not defined.
510 id(const id
&); // Not defined.
513 // NB: This class is always a static data member, and thus can be
514 // counted on to be zero-initialized.
519 _M_id() const throw();
523 // Implementation object for locale.
529 friend class locale::facet
;
531 template<typename _Facet
>
533 has_facet(const locale
&) throw();
535 template<typename _Facet
>
537 use_facet(const locale
&);
539 template<typename _Cache
>
540 friend struct __use_cache
;
544 _Atomic_word _M_refcount
;
545 const facet
** _M_facets
;
546 size_t _M_facets_size
;
547 const facet
** _M_caches
;
549 static const locale::id
* const _S_id_ctype
[];
550 static const locale::id
* const _S_id_numeric
[];
551 static const locale::id
* const _S_id_collate
[];
552 static const locale::id
* const _S_id_time
[];
553 static const locale::id
* const _S_id_monetary
[];
554 static const locale::id
* const _S_id_messages
[];
555 static const locale::id
* const* const _S_facet_categories
[];
558 _M_add_reference() throw()
559 { __gnu_cxx::__atomic_add_dispatch(&_M_refcount
, 1); }
562 _M_remove_reference() throw()
564 // Be race-detector-friendly. For more info see bits/c++config.
565 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount
);
566 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount
, -1) == 1)
568 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount
);
576 _Impl(const _Impl
&, size_t);
577 _Impl(const char*, size_t);
578 _Impl(size_t) throw();
582 _Impl(const _Impl
&); // Not defined.
585 operator=(const _Impl
&); // Not defined.
592 // We must actually compare all the _M_names: can be all equal!
593 for (size_t __i
= 0; __ret
&& __i
< _S_categories_size
- 1; ++__i
)
594 __ret
= __builtin_strcmp(_M_names
[__i
], _M_names
[__i
+ 1]) == 0;
599 _M_replace_categories(const _Impl
*, category
);
602 _M_replace_category(const _Impl
*, const locale::id
* const*);
605 _M_replace_facet(const _Impl
*, const locale::id
*);
608 _M_install_facet(const locale::id
*, const facet
*);
610 template<typename _Facet
>
612 _M_init_facet(_Facet
* __facet
)
613 { _M_install_facet(&_Facet::id
, __facet
); }
615 template<typename _Facet
>
617 _M_init_facet_unchecked(_Facet
* __facet
)
619 __facet
->_M_add_reference();
620 _M_facets
[_Facet::id
._M_id()] = __facet
;
624 _M_install_cache(const facet
*, size_t);
626 void _M_init_extra(facet
**);
627 void _M_init_extra(void*, void*, const char*, const char*);
629 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
630 void _M_init_extra_ldbl128(bool);
636 * @brief Facet for localized string comparison.
638 * This facet encapsulates the code to compare strings in a localized
641 * The collate template uses protected virtual functions to provide
642 * the actual results. The public accessors forward the call to
643 * the virtual functions. These virtual functions are hooks for
644 * developers to implement the behavior they require from the
647 template<typename _CharT
>
648 class _GLIBCXX_NAMESPACE_CXX11 collate
: public locale::facet
654 typedef _CharT char_type
;
655 typedef basic_string
<_CharT
> string_type
;
659 // Underlying "C" library locale information saved from
660 // initialization, needed by collate_byname as well.
661 __c_locale _M_c_locale_collate
;
664 /// Numpunct facet id.
665 static locale::id id
;
668 * @brief Constructor performs initialization.
670 * This is the constructor provided by the standard.
672 * @param __refs Passed to the base facet class.
675 collate(size_t __refs
= 0)
676 : facet(__refs
), _M_c_locale_collate(_S_get_c_locale())
680 * @brief Internal constructor. Not for general use.
682 * This is a constructor for use by the library itself to set up new
685 * @param __cloc The C locale.
686 * @param __refs Passed to the base facet class.
689 collate(__c_locale __cloc
, size_t __refs
= 0)
690 : facet(__refs
), _M_c_locale_collate(_S_clone_c_locale(__cloc
))
694 * @brief Compare two strings.
696 * This function compares two strings and returns the result by calling
697 * collate::do_compare().
699 * @param __lo1 Start of string 1.
700 * @param __hi1 End of string 1.
701 * @param __lo2 Start of string 2.
702 * @param __hi2 End of string 2.
703 * @return 1 if string1 > string2, -1 if string1 < string2, else 0.
706 compare(const _CharT
* __lo1
, const _CharT
* __hi1
,
707 const _CharT
* __lo2
, const _CharT
* __hi2
) const
708 { return this->do_compare(__lo1
, __hi1
, __lo2
, __hi2
); }
711 * @brief Transform string to comparable form.
713 * This function is a wrapper for strxfrm functionality. It takes the
714 * input string and returns a modified string that can be directly
715 * compared to other transformed strings. In the C locale, this
716 * function just returns a copy of the input string. In some other
717 * locales, it may replace two chars with one, change a char for
718 * another, etc. It does so by returning collate::do_transform().
720 * @param __lo Start of string.
721 * @param __hi End of string.
722 * @return Transformed string_type.
725 transform(const _CharT
* __lo
, const _CharT
* __hi
) const
726 { return this->do_transform(__lo
, __hi
); }
729 * @brief Return hash of a string.
731 * This function computes and returns a hash on the input string. It
732 * does so by returning collate::do_hash().
734 * @param __lo Start of string.
735 * @param __hi End of string.
736 * @return Hash value.
739 hash(const _CharT
* __lo
, const _CharT
* __hi
) const
740 { return this->do_hash(__lo
, __hi
); }
742 // Used to abstract out _CharT bits in virtual member functions, below.
744 _M_compare(const _CharT
*, const _CharT
*) const throw();
747 _M_transform(_CharT
*, const _CharT
*, size_t) const throw();
753 { _S_destroy_c_locale(_M_c_locale_collate
); }
756 * @brief Compare two strings.
758 * This function is a hook for derived classes to change the value
759 * returned. @see compare().
761 * @param __lo1 Start of string 1.
762 * @param __hi1 End of string 1.
763 * @param __lo2 Start of string 2.
764 * @param __hi2 End of string 2.
765 * @return 1 if string1 > string2, -1 if string1 < string2, else 0.
768 do_compare(const _CharT
* __lo1
, const _CharT
* __hi1
,
769 const _CharT
* __lo2
, const _CharT
* __hi2
) const;
772 * @brief Transform string to comparable form.
774 * This function is a hook for derived classes to change the value
779 * @return transformed string.
782 do_transform(const _CharT
* __lo
, const _CharT
* __hi
) const;
785 * @brief Return hash of a string.
787 * This function computes and returns a hash on the input string. This
788 * function is a hook for derived classes to change the value returned.
790 * @param __lo Start of string.
791 * @param __hi End of string.
792 * @return Hash value.
795 do_hash(const _CharT
* __lo
, const _CharT
* __hi
) const;
798 template<typename _CharT
>
799 locale::id collate
<_CharT
>::id
;
804 collate
<char>::_M_compare(const char*, const char*) const throw();
808 collate
<char>::_M_transform(char*, const char*, size_t) const throw();
810 #ifdef _GLIBCXX_USE_WCHAR_T
813 collate
<wchar_t>::_M_compare(const wchar_t*, const wchar_t*) const throw();
817 collate
<wchar_t>::_M_transform(wchar_t*, const wchar_t*, size_t) const throw();
820 /// class collate_byname [22.2.4.2].
821 template<typename _CharT
>
822 class _GLIBCXX_NAMESPACE_CXX11 collate_byname
: public collate
<_CharT
>
827 typedef _CharT char_type
;
828 typedef basic_string
<_CharT
> string_type
;
832 collate_byname(const char* __s
, size_t __refs
= 0)
833 : collate
<_CharT
>(__refs
)
835 if (__builtin_strcmp(__s
, "C") != 0
836 && __builtin_strcmp(__s
, "POSIX") != 0)
838 this->_S_destroy_c_locale(this->_M_c_locale_collate
);
839 this->_S_create_c_locale(this->_M_c_locale_collate
, __s
);
843 #if __cplusplus >= 201103L
845 collate_byname(const string
& __s
, size_t __refs
= 0)
846 : collate_byname(__s
.c_str(), __refs
) { }
851 ~collate_byname() { }
854 _GLIBCXX_END_NAMESPACE_VERSION
857 # include <bits/locale_classes.tcc>