1// Locale support -*- C++ -*- 
2 
3// Copyright (C) 1997-2019 Free Software Foundation, Inc. 
4// 
5// This file is part of the GNU ISO C++ Library. This library is free 
6// software; you can redistribute it and/or modify it under the 
7// terms of the GNU General Public License as published by the 
8// Free Software Foundation; either version 3, or (at your option) 
9// any later version. 
10 
11// This library is distributed in the hope that it will be useful, 
12// but WITHOUT ANY WARRANTY; without even the implied warranty of 
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
14// GNU General Public License for more details. 
15 
16// Under Section 7 of GPL version 3, you are granted additional 
17// permissions described in the GCC Runtime Library Exception, version 
18// 3.1, as published by the Free Software Foundation. 
19 
20// You should have received a copy of the GNU General Public License and 
21// a copy of the GCC Runtime Library Exception along with this program; 
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 
23// <http://www.gnu.org/licenses/>. 
24 
25/** @file 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 
43namespace std _GLIBCXX_VISIBILITY(default) 
44{ 
45_GLIBCXX_BEGIN_NAMESPACE_VERSION 
46 
47 // 22.1.1 Class locale 
48 /** 
49 * @brief Container class for localization functionality. 
50 * @ingroup locales 
51 * 
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. 
56 * 
57 * Constructing C++ locales does not change the C library locale. 
58 * 
59 * This library supports efficient construction and copying of locales 
60 * through a reference counting implementation of the locale class. 
61 */ 
62 class locale 
63 { 
64 public: 
65 // Types: 
66 /// Definition of locale::category. 
67 typedef int category; 
68 
69 // Forward decls and friends: 
70 class facet; 
71 class id; 
72 class _Impl; 
73 
74 friend class facet; 
75 friend class _Impl; 
76 
77 template<typename _Facet> 
78 friend bool 
79 has_facet(const locale&) throw(); 
80 
81 template<typename _Facet> 
82 friend const _Facet& 
83 use_facet(const locale&); 
84 
85 template<typename _Cache> 
86 friend struct __use_cache; 
87 
88 //@{ 
89 /** 
90 * @brief Category values. 
91 * 
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. 
95 * 
96 * NB: Order must match _S_facet_categories definition in locale.cc 
97 */ 
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); 
107 //@} 
108 
109 // Construct/copy/destroy: 
110 
111 /** 
112 * @brief Default constructor. 
113 * 
114 * Constructs a copy of the global locale. If no locale has been 
115 * explicitly set, this is the C locale. 
116 */ 
117 locale() throw(); 
118 
119 /** 
120 * @brief Copy constructor. 
121 * 
122 * Constructs a copy of @a other. 
123 * 
124 * @param __other The locale to copy. 
125 */ 
126 locale(const locale& __other) throw(); 
127 
128 /** 
129 * @brief Named locale constructor. 
130 * 
131 * Constructs a copy of the named C library locale. 
132 * 
133 * @param __s Name of the locale to construct. 
134 * @throw std::runtime_error if __s is null or an undefined locale. 
135 */ 
136 explicit 
137 locale(const char* __s); 
138 
139 /** 
140 * @brief Construct locale with facets from another locale. 
141 * 
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. 
145 * 
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. 
150 */ 
151 locale(const locale& __base, const char* __s, category __cat); 
152 
153#if __cplusplus >= 201103L 
154 /** 
155 * @brief Named locale constructor. 
156 * 
157 * Constructs a copy of the named C library locale. 
158 * 
159 * @param __s Name of the locale to construct. 
160 * @throw std::runtime_error if __s is an undefined locale. 
161 */ 
162 explicit 
163 locale(const std::string& __s) : locale(__s.c_str()) { } 
164 
165 /** 
166 * @brief Construct locale with facets from another locale. 
167 * 
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. 
171 * 
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. 
176 */ 
177 locale(const locale& __base, const std::string& __s, category __cat) 
178 : locale(__base, __s.c_str(), __cat) { } 
179#endif 
180 
181 /** 
182 * @brief Construct locale with facets from another locale. 
183 * 
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. 
187 * 
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. 
191 */ 
192 locale(const locale& __base, const locale& __add, category __cat); 
193 
194 /** 
195 * @brief Construct locale with another facet. 
196 * 
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. 
201 * 
202 * @param __other The locale to copy. 
203 * @param __f The facet to add in. 
204 */ 
205 template<typename _Facet> 
206 locale(const locale& __other, _Facet* __f); 
207 
208 /// Locale destructor. 
209 ~locale() throw(); 
210 
211 /** 
212 * @brief Assignment operator. 
213 * 
214 * Set this locale to be a copy of @a other. 
215 * 
216 * @param __other The locale to copy. 
217 * @return A reference to this locale. 
218 */ 
219 const locale& 
220 operator=(const locale& __other) throw(); 
221 
222 /** 
223 * @brief Construct locale with another facet. 
224 * 
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 
227 * locale. 
228 * 
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. 
233 */ 
234 template<typename _Facet> 
235 locale 
236 combine(const locale& __other) const; 
237 
238 // Locale operations: 
239 /** 
240 * @brief Return locale name. 
241 * @return Locale name or "*" if unnamed. 
242 */ 
243 _GLIBCXX_DEFAULT_ABI_TAG 
244 string 
245 name() const; 
246 
247 /** 
248 * @brief Locale equality. 
249 * 
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. 
253 */ 
254 bool 
255 operator==(const locale& __other) const throw(); 
256 
257 /** 
258 * @brief Locale inequality. 
259 * 
260 * @param __other The locale to compare against. 
261 * @return ! (*this == __other) 
262 */ 
263 bool 
264 operator!=(const locale& __other) const throw() 
265 { return !(this->operator==(__other)); } 
266 
267 /** 
268 * @brief Compare two strings according to collate. 
269 * 
270 * Template operator to compare two strings using the compare function of 
271 * the collate facet in this locale. One use is to provide the locale to 
272 * the sort function. For example, a vector v of strings could be sorted 
273 * according to locale loc by doing: 
274 * @code 
275 * std::sort(v.begin(), v.end(), loc); 
276 * @endcode 
277 * 
278 * @param __s1 First string to compare. 
279 * @param __s2 Second string to compare. 
280 * @return True if collate<_Char> facet compares __s1 < __s2, else false. 
281 */ 
282 template<typename _Char, typename _Traits, typename _Alloc> 
283 bool 
284 operator()(const basic_string<_Char, _Traits, _Alloc>& __s1, 
285 const basic_string<_Char, _Traits, _Alloc>& __s2) const; 
286 
287 // Global locale objects: 
288 /** 
289 * @brief Set global locale 
290 * 
291 * This function sets the global locale to the argument and returns a 
292 * copy of the previous global locale. If the argument has a name, it 
293 * will also call std::setlocale(LC_ALL, loc.name()). 
294 * 
295 * @param __loc The new locale to make global. 
296 * @return Copy of the old global locale. 
297 */ 
298 static locale 
299 global(const locale& __loc); 
300 
301 /** 
302 * @brief Return reference to the C locale. 
303 */ 
304 static const locale& 
305 classic(); 
306 
307 private: 
308 // The (shared) implementation 
309 _Impl* _M_impl; 
310 
311 // The "C" reference locale 
312 static _Impl* _S_classic; 
313 
314 // Current global locale 
315 static _Impl* _S_global; 
316 
317 // Names of underlying locale categories. 
318 // NB: locale::global() has to know how to modify all the 
319 // underlying categories, not just the ones required by the C++ 
320 // standard. 
321 static const char* const* const _S_categories; 
322 
323 // Number of standard categories. For C++, these categories are 
324 // collate, ctype, monetary, numeric, time, and messages. These 
325 // directly correspond to ISO C99 macros LC_COLLATE, LC_CTYPE, 
326 // LC_MONETARY, LC_NUMERIC, and LC_TIME. In addition, POSIX (IEEE 
327 // 1003.1-2001) specifies LC_MESSAGES. 
328 // In addition to the standard categories, the underlying 
329 // operating system is allowed to define extra LC_* 
330 // macros. For GNU systems, the following are also valid: 
331 // LC_PAPER, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_MEASUREMENT, 
332 // and LC_IDENTIFICATION. 
333 enum { _S_categories_size = 6 + _GLIBCXX_NUM_CATEGORIES }; 
334 
335#ifdef __GTHREADS 
336 static __gthread_once_t _S_once; 
337#endif 
338 
339 explicit 
340 locale(_Impl*) throw(); 
341 
342 static void 
343 _S_initialize(); 
344 
345 static void 
346 _S_initialize_once() throw(); 
347 
348 static category 
349 _S_normalize_category(category); 
350 
351 void 
352 _M_coalesce(const locale& __base, const locale& __add, category __cat); 
353 
354#if _GLIBCXX_USE_CXX11_ABI 
355 static const id* const _S_twinned_facets[]; 
356#endif 
357 }; 
358 
359 
360 // 22.1.1.1.2 Class locale::facet 
361 /** 
362 * @brief Localization functionality base class. 
363 * @ingroup locales 
364 * 
365 * The facet class is the base class for a localization feature, such as 
366 * money, time, and number printing. It provides common support for facets 
367 * and reference management. 
368 * 
369 * Facets may not be copied or assigned. 
370 */ 
371 class locale::facet 
372 { 
373 private: 
374 friend class locale; 
375 friend class locale::_Impl; 
376 
377 mutable _Atomic_word _M_refcount; 
378 
379 // Contains data from the underlying "C" library for the classic locale. 
380 static __c_locale _S_c_locale; 
381 
382 // String literal for the name of the classic locale. 
383 static const char _S_c_name[2]; 
384 
385#ifdef __GTHREADS 
386 static __gthread_once_t _S_once; 
387#endif 
388 
389 static void 
390 _S_initialize_once(); 
391 
392 protected: 
393 /** 
394 * @brief Facet constructor. 
395 * 
396 * This is the constructor provided by the standard. If refs is 0, the 
397 * facet is destroyed when the last referencing locale is destroyed. 
398 * Otherwise the facet will never be destroyed. 
399 * 
400 * @param __refs The initial value for reference count. 
401 */ 
402 explicit 
403 facet(size_t __refs = 0) throw() : _M_refcount(__refs ? 1 : 0) 
404 { } 
405 
406 /// Facet destructor. 
407 virtual 
408 ~facet(); 
409 
410 static void 
411 _S_create_c_locale(__c_locale& __cloc, const char* __s, 
412 __c_locale __old = 0); 
413 
414 static __c_locale 
415 _S_clone_c_locale(__c_locale& __cloc) throw(); 
416 
417 static void 
418 _S_destroy_c_locale(__c_locale& __cloc); 
419 
420 static __c_locale 
421 _S_lc_ctype_c_locale(__c_locale __cloc, const char* __s); 
422 
423 // Returns data from the underlying "C" library data for the 
424 // classic locale. 
425 static __c_locale 
426 _S_get_c_locale(); 
427 
428 _GLIBCXX_CONST static const char* 
429 _S_get_c_name() throw(); 
430 
431#if __cplusplus < 201103L 
432 private: 
433 facet(const facet&); // Not defined. 
434 
435 facet& 
436 operator=(const facet&); // Not defined. 
437#else 
438 facet(const facet&) = delete; 
439 
440 facet& 
441 operator=(const facet&) = delete; 
442#endif 
443 
444 private: 
445 void 
446 _M_add_reference() const throw() 
447 { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); } 
448 
449 void 
450 _M_remove_reference() const throw() 
451 { 
452 // Be race-detector-friendly. For more info see bits/c++config. 
453 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount); 
454 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1) == 1) 
455 { 
456 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount); 
457 __try 
458 { delete this; } 
459 __catch(...) 
460 { } 
461 } 
462 } 
463 
464 const facet* _M_sso_shim(const id*) const; 
465 const facet* _M_cow_shim(const id*) const; 
466 
467 protected: 
468 class __shim; // For internal use only. 
469 }; 
470 
471 
472 // 22.1.1.1.3 Class locale::id 
473 /** 
474 * @brief Facet ID class. 
475 * @ingroup locales 
476 * 
477 * The ID class provides facets with an index used to identify them. 
478 * Every facet class must define a public static member locale::id, or be 
479 * derived from a facet that provides this member, otherwise the facet 
480 * cannot be used in a locale. The locale::id ensures that each class 
481 * type gets a unique identifier. 
482 */ 
483 class locale::id 
484 { 
485 private: 
486 friend class locale; 
487 friend class locale::_Impl; 
488 
489 template<typename _Facet> 
490 friend const _Facet& 
491 use_facet(const locale&); 
492 
493 template<typename _Facet> 
494 friend bool 
495 has_facet(const locale&) throw(); 
496 
497 // NB: There is no accessor for _M_index because it may be used 
498 // before the constructor is run; the effect of calling a member 
499 // function (even an inline) would be undefined. 
500 mutable size_t _M_index; 
501 
502 // Last id number assigned. 
503 static _Atomic_word _S_refcount; 
504 
505 void 
506 operator=(const id&); // Not defined. 
507 
508 id(const id&); // Not defined. 
509 
510 public: 
511 // NB: This class is always a static data member, and thus can be 
512 // counted on to be zero-initialized. 
513 /// Constructor. 
514 id() { } 
515 
516 size_t 
517 _M_id() const throw(); 
518 }; 
519 
520 
521 // Implementation object for locale. 
522 class locale::_Impl 
523 { 
524 public: 
525 // Friends. 
526 friend class locale; 
527 friend class locale::facet; 
528 
529 template<typename _Facet> 
530 friend bool 
531 has_facet(const locale&) throw(); 
532 
533 template<typename _Facet> 
534 friend const _Facet& 
535 use_facet(const locale&); 
536 
537 template<typename _Cache> 
538 friend struct __use_cache; 
539 
540 private: 
541 // Data Members. 
542 _Atomic_word _M_refcount; 
543 const facet** _M_facets; 
544 size_t _M_facets_size; 
545 const facet** _M_caches; 
546 char** _M_names; 
547 static const locale::id* const _S_id_ctype[]; 
548 static const locale::id* const _S_id_numeric[]; 
549 static const locale::id* const _S_id_collate[]; 
550 static const locale::id* const _S_id_time[]; 
551 static const locale::id* const _S_id_monetary[]; 
552 static const locale::id* const _S_id_messages[]; 
553 static const locale::id* const* const _S_facet_categories[]; 
554 
555 void 
556 _M_add_reference() throw() 
557 { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); } 
558 
559 void 
560 _M_remove_reference() throw() 
561 { 
562 // Be race-detector-friendly. For more info see bits/c++config. 
563 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount); 
564 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1) == 1) 
565 { 
566 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount); 
567 __try 
568 { delete this; } 
569 __catch(...) 
570 { } 
571 } 
572 } 
573 
574 _Impl(const _Impl&, size_t); 
575 _Impl(const char*, size_t); 
576 _Impl(size_t) throw(); 
577 
578 ~_Impl() throw(); 
579 
580 _Impl(const _Impl&); // Not defined. 
581 
582 void 
583 operator=(const _Impl&); // Not defined. 
584 
585 bool 
586 _M_check_same_name() 
587 { 
588 bool __ret = true; 
589 if (_M_names[1]) 
590 // We must actually compare all the _M_names: can be all equal! 
591 for (size_t __i = 0; __ret && __i < _S_categories_size - 1; ++__i) 
592 __ret = __builtin_strcmp(_M_names[__i], _M_names[__i + 1]) == 0; 
593 return __ret; 
594 } 
595 
596 void 
597 _M_replace_categories(const _Impl*, category); 
598 
599 void 
600 _M_replace_category(const _Impl*, const locale::id* const*); 
601 
602 void 
603 _M_replace_facet(const _Impl*, const locale::id*); 
604 
605 void 
606 _M_install_facet(const locale::id*, const facet*); 
607 
608 template<typename _Facet> 
609 void 
610 _M_init_facet(_Facet* __facet) 
611 { _M_install_facet(&_Facet::id, __facet); } 
612 
613 template<typename _Facet> 
614 void 
615 _M_init_facet_unchecked(_Facet* __facet) 
616 { 
617 __facet->_M_add_reference(); 
618 _M_facets[_Facet::id._M_id()] = __facet; 
619 } 
620 
621 void 
622 _M_install_cache(const facet*, size_t); 
623 
624 void _M_init_extra(facet**); 
625 void _M_init_extra(void*, void*, const char*, const char*); 
626 }; 
627 
628 
629 /** 
630 * @brief Facet for localized string comparison. 
631 * 
632 * This facet encapsulates the code to compare strings in a localized 
633 * manner. 
634 * 
635 * The collate template uses protected virtual functions to provide 
636 * the actual results. The public accessors forward the call to 
637 * the virtual functions. These virtual functions are hooks for 
638 * developers to implement the behavior they require from the 
639 * collate facet. 
640 */ 
641 template<typename _CharT> 
642 class _GLIBCXX_NAMESPACE_CXX11 collate : public locale::facet 
643 { 
644 public: 
645 // Types: 
646 //@{ 
647 /// Public typedefs 
648 typedef _CharT char_type; 
649 typedef basic_string<_CharT> string_type; 
650 //@} 
651 
652 protected: 
653 // Underlying "C" library locale information saved from 
654 // initialization, needed by collate_byname as well. 
655 __c_locale _M_c_locale_collate; 
656 
657 public: 
658 /// Numpunct facet id. 
659 static locale::id id; 
660 
661 /** 
662 * @brief Constructor performs initialization. 
663 * 
664 * This is the constructor provided by the standard. 
665 * 
666 * @param __refs Passed to the base facet class. 
667 */ 
668 explicit 
669 collate(size_t __refs = 0) 
670 : facet(__refs), _M_c_locale_collate(_S_get_c_locale()) 
671 { } 
672 
673 /** 
674 * @brief Internal constructor. Not for general use. 
675 * 
676 * This is a constructor for use by the library itself to set up new 
677 * locales. 
678 * 
679 * @param __cloc The C locale. 
680 * @param __refs Passed to the base facet class. 
681 */ 
682 explicit 
683 collate(__c_locale __cloc, size_t __refs = 0) 
684 : facet(__refs), _M_c_locale_collate(_S_clone_c_locale(__cloc)) 
685 { } 
686 
687 /** 
688 * @brief Compare two strings. 
689 * 
690 * This function compares two strings and returns the result by calling 
691 * collate::do_compare(). 
692 * 
693 * @param __lo1 Start of string 1. 
694 * @param __hi1 End of string 1. 
695 * @param __lo2 Start of string 2. 
696 * @param __hi2 End of string 2. 
697 * @return 1 if string1 > string2, -1 if string1 < string2, else 0. 
698 */ 
699 int 
700 compare(const _CharT* __lo1, const _CharT* __hi1, 
701 const _CharT* __lo2, const _CharT* __hi2) const 
702 { return this->do_compare(__lo1, __hi1, __lo2, __hi2); } 
703 
704 /** 
705 * @brief Transform string to comparable form. 
706 * 
707 * This function is a wrapper for strxfrm functionality. It takes the 
708 * input string and returns a modified string that can be directly 
709 * compared to other transformed strings. In the C locale, this 
710 * function just returns a copy of the input string. In some other 
711 * locales, it may replace two chars with one, change a char for 
712 * another, etc. It does so by returning collate::do_transform(). 
713 * 
714 * @param __lo Start of string. 
715 * @param __hi End of string. 
716 * @return Transformed string_type. 
717 */ 
718 string_type 
719 transform(const _CharT* __lo, const _CharT* __hi) const 
720 { return this->do_transform(__lo, __hi); } 
721 
722 /** 
723 * @brief Return hash of a string. 
724 * 
725 * This function computes and returns a hash on the input string. It 
726 * does so by returning collate::do_hash(). 
727 * 
728 * @param __lo Start of string. 
729 * @param __hi End of string. 
730 * @return Hash value. 
731 */ 
732 long 
733 hash(const _CharT* __lo, const _CharT* __hi) const 
734 { return this->do_hash(__lo, __hi); } 
735 
736 // Used to abstract out _CharT bits in virtual member functions, below. 
737 int 
738 _M_compare(const _CharT*, const _CharT*) const throw(); 
739 
740 size_t 
741 _M_transform(_CharT*, const _CharT*, size_t) const throw(); 
742 
743 protected: 
744 /// Destructor. 
745 virtual 
746 ~collate() 
747 { _S_destroy_c_locale(_M_c_locale_collate); } 
748 
749 /** 
750 * @brief Compare two strings. 
751 * 
752 * This function is a hook for derived classes to change the value 
753 * returned. @see compare(). 
754 * 
755 * @param __lo1 Start of string 1. 
756 * @param __hi1 End of string 1. 
757 * @param __lo2 Start of string 2. 
758 * @param __hi2 End of string 2. 
759 * @return 1 if string1 > string2, -1 if string1 < string2, else 0. 
760 */ 
761 virtual int 
762 do_compare(const _CharT* __lo1, const _CharT* __hi1, 
763 const _CharT* __lo2, const _CharT* __hi2) const; 
764 
765 /** 
766 * @brief Transform string to comparable form. 
767 * 
768 * This function is a hook for derived classes to change the value 
769 * returned. 
770 * 
771 * @param __lo Start. 
772 * @param __hi End. 
773 * @return transformed string. 
774 */ 
775 virtual string_type 
776 do_transform(const _CharT* __lo, const _CharT* __hi) const; 
777 
778 /** 
779 * @brief Return hash of a string. 
780 * 
781 * This function computes and returns a hash on the input string. This 
782 * function is a hook for derived classes to change the value returned. 
783 * 
784 * @param __lo Start of string. 
785 * @param __hi End of string. 
786 * @return Hash value. 
787 */ 
788 virtual long 
789 do_hash(const _CharT* __lo, const _CharT* __hi) const; 
790 }; 
791 
792 template<typename _CharT> 
793 locale::id collate<_CharT>::id; 
794 
795 // Specializations. 
796 template<> 
797 int 
798 collate<char>::_M_compare(const char*, const char*) const throw(); 
799 
800 template<> 
801 size_t 
802 collate<char>::_M_transform(char*, const char*, size_t) const throw(); 
803 
804#ifdef _GLIBCXX_USE_WCHAR_T 
805 template<> 
806 int 
807 collate<wchar_t>::_M_compare(const wchar_t*, const wchar_t*) const throw(); 
808 
809 template<> 
810 size_t 
811 collate<wchar_t>::_M_transform(wchar_t*, const wchar_t*, size_t) const throw(); 
812#endif 
813 
814 /// class collate_byname [22.2.4.2]. 
815 template<typename _CharT> 
816 class _GLIBCXX_NAMESPACE_CXX11 collate_byname : public collate<_CharT> 
817 { 
818 public: 
819 //@{ 
820 /// Public typedefs 
821 typedef _CharT char_type; 
822 typedef basic_string<_CharT> string_type; 
823 //@} 
824 
825 explicit 
826 collate_byname(const char* __s, size_t __refs = 0) 
827 : collate<_CharT>(__refs) 
828 { 
829 if (__builtin_strcmp(__s, "C") != 0 
830 && __builtin_strcmp(__s, "POSIX") != 0) 
831 { 
832 this->_S_destroy_c_locale(this->_M_c_locale_collate); 
833 this->_S_create_c_locale(this->_M_c_locale_collate, __s); 
834 } 
835 } 
836 
837#if __cplusplus >= 201103L 
838 explicit 
839 collate_byname(const string& __s, size_t __refs = 0) 
840 : collate_byname(__s.c_str(), __refs) { } 
841#endif 
842 
843 protected: 
844 virtual 
845 ~collate_byname() { } 
846 }; 
847 
848_GLIBCXX_END_NAMESPACE_VERSION 
849} // namespace 
850 
851# include <bits/locale_classes.tcc> 
852 
853#endif 
854