1// Locale support -*- C++ -*-
2
3// Copyright (C) 1997-2024 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file 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}
28 */
29
30//
31// ISO C++ 14882: 22.1 Locales
32//
33
34#ifndef _LOCALE_CLASSES_H
35#define _LOCALE_CLASSES_H 1
36
37#pragma GCC system_header
38
39#include <bits/localefwd.h>
40#include <string>
41#include <ext/atomicity.h>
42
43#ifdef __glibcxx_text_encoding
44#include <text_encoding>
45#endif
46
47namespace std _GLIBCXX_VISIBILITY(default)
48{
49_GLIBCXX_BEGIN_NAMESPACE_VERSION
50
51 // 22.1.1 Class locale
52 /**
53 * @brief Container class for localization functionality.
54 * @ingroup locales
55 *
56 * The locale class is first a class wrapper for C library locales. It is
57 * also an extensible container for user-defined localization. A locale is
58 * a collection of facets that implement various localization features such
59 * as money, time, and number printing.
60 *
61 * Constructing C++ locales does not change the C library locale.
62 *
63 * This library supports efficient construction and copying of locales
64 * through a reference counting implementation of the locale class.
65 */
66 class locale
67 {
68 public:
69 // Types:
70 /// Definition of locale::category.
71 typedef int category;
72
73 // Forward decls and friends:
74 class facet;
75 class id;
76 class _Impl;
77
78 friend class facet;
79 friend class _Impl;
80
81 template<typename _Facet>
82 friend bool
83 has_facet(const locale&) throw();
84
85 template<typename _Facet>
86 friend const _Facet&
87 use_facet(const locale&);
88
89 template<typename _Facet>
90 friend const _Facet*
91 __try_use_facet(const locale&) _GLIBCXX_NOTHROW;
92
93 template<typename _Cache>
94 friend struct __use_cache;
95
96 ///@{
97 /**
98 * @brief Category values.
99 *
100 * The standard category values are none, ctype, numeric, collate, time,
101 * monetary, and messages. They form a bitmask that supports union and
102 * intersection. The category all is the union of these values.
103 *
104 * NB: Order must match _S_facet_categories definition in locale.cc
105 */
106 static const category none = 0;
107 static const category ctype = 1L << 0;
108 static const category numeric = 1L << 1;
109 static const category collate = 1L << 2;
110 static const category time = 1L << 3;
111 static const category monetary = 1L << 4;
112 static const category messages = 1L << 5;
113 static const category all = (ctype | numeric | collate |
114 time | monetary | messages);
115 ///@}
116
117 // Construct/copy/destroy:
118
119 /**
120 * @brief Default constructor.
121 *
122 * Constructs a copy of the global locale. If no locale has been
123 * explicitly set, this is the C locale.
124 */
125 locale() throw();
126
127 /**
128 * @brief Copy constructor.
129 *
130 * Constructs a copy of @a other.
131 *
132 * @param __other The locale to copy.
133 */
134 locale(const locale& __other) throw();
135
136 /**
137 * @brief Named locale constructor.
138 *
139 * Constructs a copy of the named C library locale.
140 *
141 * @param __s Name of the locale to construct.
142 * @throw std::runtime_error if __s is null or an undefined locale.
143 */
144 explicit
145 locale(const char* __s);
146
147 /**
148 * @brief Construct locale with facets from another locale.
149 *
150 * Constructs a copy of the locale @a base. The facets specified by @a
151 * cat are replaced with those from the locale named by @a s. If base is
152 * named, this locale instance will also be named.
153 *
154 * @param __base The locale to copy.
155 * @param __s Name of the locale to use facets from.
156 * @param __cat Set of categories defining the facets to use from __s.
157 * @throw std::runtime_error if __s is null or an undefined locale.
158 */
159 locale(const locale& __base, const char* __s, category __cat);
160
161#if __cplusplus >= 201103L
162 /**
163 * @brief Named locale constructor.
164 *
165 * Constructs a copy of the named C library locale.
166 *
167 * @param __s Name of the locale to construct.
168 * @throw std::runtime_error if __s is an undefined locale.
169 */
170 explicit
171 locale(const std::string& __s) : locale(__s.c_str()) { }
172
173 /**
174 * @brief Construct locale with facets from another locale.
175 *
176 * Constructs a copy of the locale @a base. The facets specified by @a
177 * cat are replaced with those from the locale named by @a s. If base is
178 * named, this locale instance will also be named.
179 *
180 * @param __base The locale to copy.
181 * @param __s Name of the locale to use facets from.
182 * @param __cat Set of categories defining the facets to use from __s.
183 * @throw std::runtime_error if __s is an undefined locale.
184 */
185 locale(const locale& __base, const std::string& __s, category __cat)
186 : locale(__base, __s.c_str(), __cat) { }
187#endif
188
189 /**
190 * @brief Construct locale with facets from another locale.
191 *
192 * Constructs a copy of the locale @a base. The facets specified by @a
193 * cat are replaced with those from the locale @a add. If @a base and @a
194 * add are named, this locale instance will also be named.
195 *
196 * @param __base The locale to copy.
197 * @param __add The locale to use facets from.
198 * @param __cat Set of categories defining the facets to use from add.
199 */
200 locale(const locale& __base, const locale& __add, category __cat);
201
202 /**
203 * @brief Construct locale with another facet.
204 *
205 * Constructs a copy of the locale @a __other. The facet @a __f
206 * is added to @a __other, replacing an existing facet of type
207 * Facet if there is one. If @a __f is null, this locale is a
208 * copy of @a __other.
209 *
210 * @param __other The locale to copy.
211 * @param __f The facet to add in.
212 */
213 template<typename _Facet>
214 locale(const locale& __other, _Facet* __f);
215
216 /// Locale destructor.
217 ~locale() throw();
218
219 /**
220 * @brief Assignment operator.
221 *
222 * Set this locale to be a copy of @a other.
223 *
224 * @param __other The locale to copy.
225 * @return A reference to this locale.
226 */
227 const locale&
228 operator=(const locale& __other) throw();
229
230 /**
231 * @brief Construct locale with another facet.
232 *
233 * Constructs and returns a new copy of this locale. Adds or replaces an
234 * existing facet of type Facet from the locale @a other into the new
235 * locale.
236 *
237 * @tparam _Facet The facet type to copy from other
238 * @param __other The locale to copy from.
239 * @return Newly constructed locale.
240 * @throw std::runtime_error if __other has no facet of type _Facet.
241 */
242 template<typename _Facet>
243 locale
244 combine(const locale& __other) const;
245
246 // Locale operations:
247 /**
248 * @brief Return locale name.
249 * @return Locale name or "*" if unnamed.
250 */
251 _GLIBCXX_DEFAULT_ABI_TAG
252 string
253 name() const;
254
255#ifdef __glibcxx_text_encoding
256# if __CHAR_BIT__ == 8
257 text_encoding
258 encoding() const;
259# else
260 text_encoding
261 encoding() const = delete;
262# endif
263#endif
264
265 /**
266 * @brief Locale equality.
267 *
268 * @param __other The locale to compare against.
269 * @return True if other and this refer to the same locale instance, are
270 * copies, or have the same name. False otherwise.
271 */
272 bool
273 operator==(const locale& __other) const throw();
274
275#if __cpp_impl_three_way_comparison < 201907L
276 /**
277 * @brief Locale inequality.
278 *
279 * @param __other The locale to compare against.
280 * @return ! (*this == __other)
281 */
282 bool
283 operator!=(const locale& __other) const throw()
284 { return !(this->operator==(__other)); }
285#endif
286
287 /**
288 * @brief Compare two strings according to collate.
289 *
290 * Template operator to compare two strings using the compare function of
291 * the collate facet in this locale. One use is to provide the locale to
292 * the sort function. For example, a vector v of strings could be sorted
293 * according to locale loc by doing:
294 * @code
295 * std::sort(v.begin(), v.end(), loc);
296 * @endcode
297 *
298 * @param __s1 First string to compare.
299 * @param __s2 Second string to compare.
300 * @return True if collate<_Char> facet compares __s1 < __s2, else false.
301 */
302 template<typename _Char, typename _Traits, typename _Alloc>
303 bool
304 operator()(const basic_string<_Char, _Traits, _Alloc>& __s1,
305 const basic_string<_Char, _Traits, _Alloc>& __s2) const;
306
307 // Global locale objects:
308 /**
309 * @brief Set global locale
310 *
311 * This function sets the global locale to the argument and returns a
312 * copy of the previous global locale. If the argument has a name, it
313 * will also call std::setlocale(LC_ALL, loc.name()).
314 *
315 * @param __loc The new locale to make global.
316 * @return Copy of the old global locale.
317 */
318 static locale
319 global(const locale& __loc);
320
321 /**
322 * @brief Return reference to the C locale.
323 */
324 static const locale&
325 classic();
326
327 private:
328 // The (shared) implementation
329 _Impl* _M_impl;
330
331 // The "C" reference locale
332 static _Impl* _S_classic;
333
334 // Current global locale
335 static _Impl* _S_global;
336
337 // Names of underlying locale categories.
338 // NB: locale::global() has to know how to modify all the
339 // underlying categories, not just the ones required by the C++
340 // standard.
341 static const char* const* const _S_categories;
342
343 // Number of standard categories. For C++, these categories are
344 // collate, ctype, monetary, numeric, time, and messages. These
345 // directly correspond to ISO C99 macros LC_COLLATE, LC_CTYPE,
346 // LC_MONETARY, LC_NUMERIC, and LC_TIME. In addition, POSIX (IEEE
347 // 1003.1-2001) specifies LC_MESSAGES.
348 // In addition to the standard categories, the underlying
349 // operating system is allowed to define extra LC_*
350 // macros. For GNU systems, the following are also valid:
351 // LC_PAPER, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_MEASUREMENT,
352 // and LC_IDENTIFICATION.
353 enum { _S_categories_size = 6 + _GLIBCXX_NUM_CATEGORIES };
354
355#ifdef __GTHREADS
356 static __gthread_once_t _S_once;
357#endif
358
359 explicit
360 locale(_Impl*) throw();
361
362 static void
363 _S_initialize();
364
365 static void
366 _S_initialize_once() throw();
367
368 static category
369 _S_normalize_category(category);
370
371 void
372 _M_coalesce(const locale& __base, const locale& __add, category __cat);
373
374#if _GLIBCXX_USE_CXX11_ABI
375 static const id* const _S_twinned_facets[];
376#endif
377 };
378
379
380 // 22.1.1.1.2 Class locale::facet
381 /**
382 * @brief Localization functionality base class.
383 * @ingroup locales
384 *
385 * The facet class is the base class for a localization feature, such as
386 * money, time, and number printing. It provides common support for facets
387 * and reference management.
388 *
389 * Facets may not be copied or assigned.
390 */
391 class locale::facet
392 {
393 private:
394 friend class locale;
395 friend class locale::_Impl;
396
397 mutable _Atomic_word _M_refcount;
398
399 // Contains data from the underlying "C" library for the classic locale.
400 static __c_locale _S_c_locale;
401
402 // String literal for the name of the classic locale.
403 static const char _S_c_name[2];
404
405#ifdef __GTHREADS
406 static __gthread_once_t _S_once;
407#endif
408
409 static void
410 _S_initialize_once();
411
412 protected:
413 /**
414 * @brief Facet constructor.
415 *
416 * This is the constructor provided by the standard. If refs is 0, the
417 * facet is destroyed when the last referencing locale is destroyed.
418 * Otherwise the facet will never be destroyed.
419 *
420 * @param __refs The initial value for reference count.
421 */
422 explicit
423 facet(size_t __refs = 0) throw() : _M_refcount(__refs ? 1 : 0)
424 { }
425
426 /// Facet destructor.
427 virtual
428 ~facet();
429
430 static void
431 _S_create_c_locale(__c_locale& __cloc, const char* __s,
432 __c_locale __old = 0);
433
434 static __c_locale
435 _S_clone_c_locale(__c_locale& __cloc) throw();
436
437 static void
438 _S_destroy_c_locale(__c_locale& __cloc);
439
440 static __c_locale
441 _S_lc_ctype_c_locale(__c_locale __cloc, const char* __s);
442
443 // Returns data from the underlying "C" library data for the
444 // classic locale.
445 static __c_locale
446 _S_get_c_locale();
447
448 _GLIBCXX_CONST static const char*
449 _S_get_c_name() throw();
450
451#if __cplusplus < 201103L
452 private:
453 facet(const facet&); // Not defined.
454
455 facet&
456 operator=(const facet&); // Not defined.
457#else
458 facet(const facet&) = delete;
459
460 facet&
461 operator=(const facet&) = delete;
462#endif
463
464 private:
465 void
466 _M_add_reference() const throw()
467 { __gnu_cxx::__atomic_add_dispatch(mem: &_M_refcount, val: 1); }
468
469 void
470 _M_remove_reference() const throw()
471 {
472 // Be race-detector-friendly. For more info see bits/c++config.
473 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
474 if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_refcount, val: -1) == 1)
475 {
476 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
477 __try
478 { delete this; }
479 __catch(...)
480 { }
481 }
482 }
483
484 const facet* _M_sso_shim(const id*) const;
485 const facet* _M_cow_shim(const id*) const;
486
487 protected:
488 class __shim; // For internal use only.
489 };
490
491
492 // 22.1.1.1.3 Class locale::id
493 /**
494 * @brief Facet ID class.
495 * @ingroup locales
496 *
497 * The ID class provides facets with an index used to identify them.
498 * Every facet class must define a public static member locale::id, or be
499 * derived from a facet that provides this member, otherwise the facet
500 * cannot be used in a locale. The locale::id ensures that each class
501 * type gets a unique identifier.
502 */
503 class locale::id
504 {
505 private:
506 friend class locale;
507 friend class locale::_Impl;
508
509 template<typename _Facet>
510 friend const _Facet&
511 use_facet(const locale&);
512
513 template<typename _Facet>
514 friend bool
515 has_facet(const locale&) throw();
516
517 template<typename _Facet>
518 friend const _Facet*
519 __try_use_facet(const locale&) _GLIBCXX_NOTHROW;
520
521 // NB: There is no accessor for _M_index because it may be used
522 // before the constructor is run; the effect of calling a member
523 // function (even an inline) would be undefined.
524 mutable size_t _M_index;
525
526 // Last id number assigned.
527 static _Atomic_word _S_refcount;
528
529 void
530 operator=(const id&); // Not defined.
531
532 id(const id&); // Not defined.
533
534 public:
535 // NB: This class is always a static data member, and thus can be
536 // counted on to be zero-initialized.
537 /// Constructor.
538 id() { }
539
540 size_t
541 _M_id() const throw();
542 };
543
544
545 // Implementation object for locale.
546 class locale::_Impl
547 {
548 public:
549 // Friends.
550 friend class locale;
551 friend class locale::facet;
552
553 template<typename _Facet>
554 friend bool
555 has_facet(const locale&) throw();
556
557 template<typename _Facet>
558 friend const _Facet&
559 use_facet(const locale&);
560
561 template<typename _Facet>
562 friend const _Facet*
563 __try_use_facet(const locale&) _GLIBCXX_NOTHROW;
564
565 template<typename _Cache>
566 friend struct __use_cache;
567
568 private:
569 // Data Members.
570 _Atomic_word _M_refcount;
571 const facet** _M_facets;
572 size_t _M_facets_size;
573 const facet** _M_caches;
574 char** _M_names;
575 static const locale::id* const _S_id_ctype[];
576 static const locale::id* const _S_id_numeric[];
577 static const locale::id* const _S_id_collate[];
578 static const locale::id* const _S_id_time[];
579 static const locale::id* const _S_id_monetary[];
580 static const locale::id* const _S_id_messages[];
581 static const locale::id* const* const _S_facet_categories[];
582
583 void
584 _M_add_reference() throw()
585 { __gnu_cxx::__atomic_add_dispatch(mem: &_M_refcount, val: 1); }
586
587 void
588 _M_remove_reference() throw()
589 {
590 // Be race-detector-friendly. For more info see bits/c++config.
591 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
592 if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_refcount, val: -1) == 1)
593 {
594 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
595 __try
596 { delete this; }
597 __catch(...)
598 { }
599 }
600 }
601
602 _Impl(const _Impl&, size_t);
603 _Impl(const char*, size_t);
604 _Impl(size_t) throw();
605
606 ~_Impl() throw();
607
608 _Impl(const _Impl&); // Not defined.
609
610 void
611 operator=(const _Impl&); // Not defined.
612
613 bool
614 _M_check_same_name()
615 {
616 bool __ret = true;
617 if (_M_names[1])
618 // We must actually compare all the _M_names: can be all equal!
619 for (size_t __i = 0; __ret && __i < _S_categories_size - 1; ++__i)
620 __ret = __builtin_strcmp(_M_names[__i], _M_names[__i + 1]) == 0;
621 return __ret;
622 }
623
624 void
625 _M_replace_categories(const _Impl*, category);
626
627 void
628 _M_replace_category(const _Impl*, const locale::id* const*);
629
630 void
631 _M_replace_facet(const _Impl*, const locale::id*);
632
633 void
634 _M_install_facet(const locale::id*, const facet*);
635
636 template<typename _Facet>
637 void
638 _M_init_facet(_Facet* __facet)
639 { _M_install_facet(&_Facet::id, __facet); }
640
641 template<typename _Facet>
642 void
643 _M_init_facet_unchecked(_Facet* __facet)
644 {
645 __facet->_M_add_reference();
646 _M_facets[_Facet::id._M_id()] = __facet;
647 }
648
649 void
650 _M_install_cache(const facet*, size_t);
651
652 void _M_init_extra(facet**);
653 void _M_init_extra(void*, void*, const char*, const char*);
654
655#ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
656 void _M_init_extra_ldbl128(bool);
657#endif
658 };
659
660
661 /**
662 * @brief Facet for localized string comparison.
663 *
664 * This facet encapsulates the code to compare strings in a localized
665 * manner.
666 *
667 * The collate template uses protected virtual functions to provide
668 * the actual results. The public accessors forward the call to
669 * the virtual functions. These virtual functions are hooks for
670 * developers to implement the behavior they require from the
671 * collate facet.
672 */
673 template<typename _CharT>
674 class _GLIBCXX_NAMESPACE_CXX11 collate : public locale::facet
675 {
676 public:
677 // Types:
678 ///@{
679 /// Public typedefs
680 typedef _CharT char_type;
681 typedef basic_string<_CharT> string_type;
682 ///@}
683
684 protected:
685 // Underlying "C" library locale information saved from
686 // initialization, needed by collate_byname as well.
687 __c_locale _M_c_locale_collate;
688
689 public:
690 /// Numpunct facet id.
691 static locale::id id;
692
693 /**
694 * @brief Constructor performs initialization.
695 *
696 * This is the constructor provided by the standard.
697 *
698 * @param __refs Passed to the base facet class.
699 */
700 explicit
701 collate(size_t __refs = 0)
702 : facet(__refs), _M_c_locale_collate(_S_get_c_locale())
703 { }
704
705 /**
706 * @brief Internal constructor. Not for general use.
707 *
708 * This is a constructor for use by the library itself to set up new
709 * locales.
710 *
711 * @param __cloc The C locale.
712 * @param __refs Passed to the base facet class.
713 */
714 explicit
715 collate(__c_locale __cloc, size_t __refs = 0)
716 : facet(__refs), _M_c_locale_collate(_S_clone_c_locale(__cloc))
717 { }
718
719 /**
720 * @brief Compare two strings.
721 *
722 * This function compares two strings and returns the result by calling
723 * collate::do_compare().
724 *
725 * @param __lo1 Start of string 1.
726 * @param __hi1 End of string 1.
727 * @param __lo2 Start of string 2.
728 * @param __hi2 End of string 2.
729 * @return 1 if string1 > string2, -1 if string1 < string2, else 0.
730 */
731 int
732 compare(const _CharT* __lo1, const _CharT* __hi1,
733 const _CharT* __lo2, const _CharT* __hi2) const
734 { return this->do_compare(__lo1, __hi1, __lo2, __hi2); }
735
736 /**
737 * @brief Transform string to comparable form.
738 *
739 * This function is a wrapper for strxfrm functionality. It takes the
740 * input string and returns a modified string that can be directly
741 * compared to other transformed strings. In the C locale, this
742 * function just returns a copy of the input string. In some other
743 * locales, it may replace two chars with one, change a char for
744 * another, etc. It does so by returning collate::do_transform().
745 *
746 * @param __lo Start of string.
747 * @param __hi End of string.
748 * @return Transformed string_type.
749 */
750 string_type
751 transform(const _CharT* __lo, const _CharT* __hi) const
752 { return this->do_transform(__lo, __hi); }
753
754 /**
755 * @brief Return hash of a string.
756 *
757 * This function computes and returns a hash on the input string. It
758 * does so by returning collate::do_hash().
759 *
760 * @param __lo Start of string.
761 * @param __hi End of string.
762 * @return Hash value.
763 */
764 long
765 hash(const _CharT* __lo, const _CharT* __hi) const
766 { return this->do_hash(__lo, __hi); }
767
768 // Used to abstract out _CharT bits in virtual member functions, below.
769 int
770 _M_compare(const _CharT*, const _CharT*) const throw();
771
772 size_t
773 _M_transform(_CharT*, const _CharT*, size_t) const throw();
774
775 protected:
776 /// Destructor.
777 virtual
778 ~collate()
779 { _S_destroy_c_locale(cloc&: _M_c_locale_collate); }
780
781 /**
782 * @brief Compare two strings.
783 *
784 * This function is a hook for derived classes to change the value
785 * returned. @see compare().
786 *
787 * @param __lo1 Start of string 1.
788 * @param __hi1 End of string 1.
789 * @param __lo2 Start of string 2.
790 * @param __hi2 End of string 2.
791 * @return 1 if string1 > string2, -1 if string1 < string2, else 0.
792 */
793 virtual int
794 do_compare(const _CharT* __lo1, const _CharT* __hi1,
795 const _CharT* __lo2, const _CharT* __hi2) const;
796
797 /**
798 * @brief Transform string to comparable form.
799 *
800 * This function is a hook for derived classes to change the value
801 * returned.
802 *
803 * @param __lo Start.
804 * @param __hi End.
805 * @return transformed string.
806 */
807 virtual string_type
808 do_transform(const _CharT* __lo, const _CharT* __hi) const;
809
810 /**
811 * @brief Return hash of a string.
812 *
813 * This function computes and returns a hash on the input string. This
814 * function is a hook for derived classes to change the value returned.
815 *
816 * @param __lo Start of string.
817 * @param __hi End of string.
818 * @return Hash value.
819 */
820 virtual long
821 do_hash(const _CharT* __lo, const _CharT* __hi) const;
822 };
823
824 template<typename _CharT>
825 locale::id collate<_CharT>::id;
826
827 // Specializations.
828 template<>
829 int
830 collate<char>::_M_compare(const char*, const char*) const throw();
831
832 template<>
833 size_t
834 collate<char>::_M_transform(char*, const char*, size_t) const throw();
835
836#ifdef _GLIBCXX_USE_WCHAR_T
837 template<>
838 int
839 collate<wchar_t>::_M_compare(const wchar_t*, const wchar_t*) const throw();
840
841 template<>
842 size_t
843 collate<wchar_t>::_M_transform(wchar_t*, const wchar_t*, size_t) const throw();
844#endif
845
846 /// class collate_byname [22.2.4.2].
847 template<typename _CharT>
848 class _GLIBCXX_NAMESPACE_CXX11 collate_byname : public collate<_CharT>
849 {
850 public:
851 ///@{
852 /// Public typedefs
853 typedef _CharT char_type;
854 typedef basic_string<_CharT> string_type;
855 ///@}
856
857 explicit
858 collate_byname(const char* __s, size_t __refs = 0)
859 : collate<_CharT>(__refs)
860 {
861 if (__builtin_strcmp(__s, "C") != 0
862 && __builtin_strcmp(__s, "POSIX") != 0)
863 {
864 this->_S_destroy_c_locale(this->_M_c_locale_collate);
865 this->_S_create_c_locale(this->_M_c_locale_collate, __s);
866 }
867 }
868
869#if __cplusplus >= 201103L
870 explicit
871 collate_byname(const string& __s, size_t __refs = 0)
872 : collate_byname(__s.c_str(), __refs) { }
873#endif
874
875 protected:
876 virtual
877 ~collate_byname() { }
878 };
879
880_GLIBCXX_END_NAMESPACE_VERSION
881} // namespace
882
883# include <bits/locale_classes.tcc>
884
885#endif
886