libstdc++
locale_classes.h
Go to the documentation of this file.
00001 // Locale support -*- C++ -*-
00002 
00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
00004 // 2006, 2007, 2008, 2009, 2010, 2011
00005 // Free Software Foundation, Inc.
00006 //
00007 // This file is part of the GNU ISO C++ Library.  This library is free
00008 // software; you can redistribute it and/or modify it under the
00009 // terms of the GNU General Public License as published by the
00010 // Free Software Foundation; either version 3, or (at your option)
00011 // any later version.
00012 
00013 // This library is distributed in the hope that it will be useful,
00014 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00015 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016 // GNU General Public License for more details.
00017 
00018 // Under Section 7 of GPL version 3, you are granted additional
00019 // permissions described in the GCC Runtime Library Exception, version
00020 // 3.1, as published by the Free Software Foundation.
00021 
00022 // You should have received a copy of the GNU General Public License and
00023 // a copy of the GCC Runtime Library Exception along with this program;
00024 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00025 // <http://www.gnu.org/licenses/>.
00026 
00027 /** @file bits/locale_classes.h
00028  *  This is an internal header file, included by other library headers.
00029  *  Do not attempt to use it directly. @headername{locale}
00030  */
00031 
00032 //
00033 // ISO C++ 14882: 22.1  Locales
00034 //
00035 
00036 #ifndef _LOCALE_CLASSES_H
00037 #define _LOCALE_CLASSES_H 1
00038 
00039 #pragma GCC system_header
00040 
00041 #include <bits/localefwd.h>
00042 #include <string>
00043 #include <ext/atomicity.h>
00044 
00045 namespace std _GLIBCXX_VISIBILITY(default)
00046 {
00047 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00048 
00049   // 22.1.1 Class locale
00050   /**
00051    *  @brief  Container class for localization functionality.
00052    *  @ingroup locales
00053    *
00054    *  The locale class is first a class wrapper for C library locales.  It is
00055    *  also an extensible container for user-defined localization.  A locale is
00056    *  a collection of facets that implement various localization features such
00057    *  as money, time, and number printing.
00058    *
00059    *  Constructing C++ locales does not change the C library locale.
00060    *
00061    *  This library supports efficient construction and copying of locales
00062    *  through a reference counting implementation of the locale class.
00063   */
00064   class locale
00065   {
00066   public:
00067     // Types:
00068     /// Definition of locale::category.
00069     typedef int category;
00070 
00071     // Forward decls and friends:
00072     class facet;
00073     class id;
00074     class _Impl;
00075 
00076     friend class facet;
00077     friend class _Impl;
00078 
00079     template<typename _Facet>
00080       friend bool
00081       has_facet(const locale&) throw();
00082 
00083     template<typename _Facet>
00084       friend const _Facet&
00085       use_facet(const locale&);
00086 
00087     template<typename _Cache>
00088       friend struct __use_cache;
00089 
00090     //@{
00091     /**
00092      *  @brief  Category values.
00093      *
00094      *  The standard category values are none, ctype, numeric, collate, time,
00095      *  monetary, and messages.  They form a bitmask that supports union and
00096      *  intersection.  The category all is the union of these values.
00097      *
00098      *  NB: Order must match _S_facet_categories definition in locale.cc
00099     */
00100     static const category none      = 0;
00101     static const category ctype     = 1L << 0;
00102     static const category numeric   = 1L << 1;
00103     static const category collate   = 1L << 2;
00104     static const category time      = 1L << 3;
00105     static const category monetary  = 1L << 4;
00106     static const category messages  = 1L << 5;
00107     static const category all       = (ctype | numeric | collate |
00108                        time  | monetary | messages);
00109     //@}
00110 
00111     // Construct/copy/destroy:
00112 
00113     /**
00114      *  @brief  Default constructor.
00115      *
00116      *  Constructs a copy of the global locale.  If no locale has been
00117      *  explicitly set, this is the C locale.
00118     */
00119     locale() throw();
00120 
00121     /**
00122      *  @brief  Copy constructor.
00123      *
00124      *  Constructs a copy of @a other.
00125      *
00126      *  @param  __other  The locale to copy.
00127     */
00128     locale(const locale& __other) throw();
00129 
00130     /**
00131      *  @brief  Named locale constructor.
00132      *
00133      *  Constructs a copy of the named C library locale.
00134      *
00135      *  @param  __s  Name of the locale to construct.
00136      *  @throw  std::runtime_error if __s is null or an undefined locale.
00137     */
00138     explicit
00139     locale(const char* __s);
00140 
00141     /**
00142      *  @brief  Construct locale with facets from another locale.
00143      *
00144      *  Constructs a copy of the locale @a base.  The facets specified by @a
00145      *  cat are replaced with those from the locale named by @a s.  If base is
00146      *  named, this locale instance will also be named.
00147      *
00148      *  @param  __base  The locale to copy.
00149      *  @param  __s  Name of the locale to use facets from.
00150      *  @param  __cat  Set of categories defining the facets to use from __s.
00151      *  @throw  std::runtime_error if __s is null or an undefined locale.
00152     */
00153     locale(const locale& __base, const char* __s, category __cat);
00154 
00155     /**
00156      *  @brief  Construct locale with facets from another locale.
00157      *
00158      *  Constructs a copy of the locale @a base.  The facets specified by @a
00159      *  cat are replaced with those from the locale @a add.  If @a base and @a
00160      *  add are named, this locale instance will also be named.
00161      *
00162      *  @param  __base  The locale to copy.
00163      *  @param  __add  The locale to use facets from.
00164      *  @param  __cat  Set of categories defining the facets to use from add.
00165     */
00166     locale(const locale& __base, const locale& __add, category __cat);
00167 
00168     /**
00169      *  @brief  Construct locale with another facet.
00170      *
00171      *  Constructs a copy of the locale @a __other.  The facet @a __f
00172      *  is added to @a __other, replacing an existing facet of type
00173      *  Facet if there is one.  If @a __f is null, this locale is a
00174      *  copy of @a __other.
00175      *
00176      *  @param  __other  The locale to copy.
00177      *  @param  __f  The facet to add in.
00178     */
00179     template<typename _Facet>
00180       locale(const locale& __other, _Facet* __f);
00181 
00182     /// Locale destructor.
00183     ~locale() throw();
00184 
00185     /**
00186      *  @brief  Assignment operator.
00187      *
00188      *  Set this locale to be a copy of @a other.
00189      *
00190      *  @param  __other  The locale to copy.
00191      *  @return  A reference to this locale.
00192     */
00193     const locale&
00194     operator=(const locale& __other) throw();
00195 
00196     /**
00197      *  @brief  Construct locale with another facet.
00198      *
00199      *  Constructs and returns a new copy of this locale.  Adds or replaces an
00200      *  existing facet of type Facet from the locale @a other into the new
00201      *  locale.
00202      *
00203      *  @tparam  _Facet  The facet type to copy from other
00204      *  @param  __other  The locale to copy from.
00205      *  @return  Newly constructed locale.
00206      *  @throw  std::runtime_error if __other has no facet of type _Facet.
00207     */
00208     template<typename _Facet>
00209       locale
00210       combine(const locale& __other) const;
00211 
00212     // Locale operations:
00213     /**
00214      *  @brief  Return locale name.
00215      *  @return  Locale name or "*" if unnamed.
00216     */
00217     string
00218     name() const;
00219 
00220     /**
00221      *  @brief  Locale equality.
00222      *
00223      *  @param  __other  The locale to compare against.
00224      *  @return  True if other and this refer to the same locale instance, are
00225      *       copies, or have the same name.  False otherwise.
00226     */
00227     bool
00228     operator==(const locale& __other) const throw();
00229 
00230     /**
00231      *  @brief  Locale inequality.
00232      *
00233      *  @param  __other  The locale to compare against.
00234      *  @return  ! (*this == __other)
00235     */
00236     bool
00237     operator!=(const locale& __other) const throw()
00238     { return !(this->operator==(__other)); }
00239 
00240     /**
00241      *  @brief  Compare two strings according to collate.
00242      *
00243      *  Template operator to compare two strings using the compare function of
00244      *  the collate facet in this locale.  One use is to provide the locale to
00245      *  the sort function.  For example, a vector v of strings could be sorted
00246      *  according to locale loc by doing:
00247      *  @code
00248      *  std::sort(v.begin(), v.end(), loc);
00249      *  @endcode
00250      *
00251      *  @param  __s1  First string to compare.
00252      *  @param  __s2  Second string to compare.
00253      *  @return  True if collate<_Char> facet compares __s1 < __s2, else false.
00254     */
00255     template<typename _Char, typename _Traits, typename _Alloc>
00256       bool
00257       operator()(const basic_string<_Char, _Traits, _Alloc>& __s1,
00258          const basic_string<_Char, _Traits, _Alloc>& __s2) const;
00259 
00260     // Global locale objects:
00261     /**
00262      *  @brief  Set global locale
00263      *
00264      *  This function sets the global locale to the argument and returns a
00265      *  copy of the previous global locale.  If the argument has a name, it
00266      *  will also call std::setlocale(LC_ALL, loc.name()).
00267      *
00268      *  @param  __loc  The new locale to make global.
00269      *  @return  Copy of the old global locale.
00270     */
00271     static locale
00272     global(const locale& __loc);
00273 
00274     /**
00275      *  @brief  Return reference to the C locale.
00276     */
00277     static const locale&
00278     classic();
00279 
00280   private:
00281     // The (shared) implementation
00282     _Impl*      _M_impl;
00283 
00284     // The "C" reference locale
00285     static _Impl*       _S_classic;
00286 
00287     // Current global locale
00288     static _Impl*   _S_global;
00289 
00290     // Names of underlying locale categories.
00291     // NB: locale::global() has to know how to modify all the
00292     // underlying categories, not just the ones required by the C++
00293     // standard.
00294     static const char* const* const _S_categories;
00295 
00296     // Number of standard categories. For C++, these categories are
00297     // collate, ctype, monetary, numeric, time, and messages. These
00298     // directly correspond to ISO C99 macros LC_COLLATE, LC_CTYPE,
00299     // LC_MONETARY, LC_NUMERIC, and LC_TIME. In addition, POSIX (IEEE
00300     // 1003.1-2001) specifies LC_MESSAGES.
00301     // In addition to the standard categories, the underlying
00302     // operating system is allowed to define extra LC_*
00303     // macros. For GNU systems, the following are also valid:
00304     // LC_PAPER, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_MEASUREMENT,
00305     // and LC_IDENTIFICATION.
00306     enum { _S_categories_size = 6 + _GLIBCXX_NUM_CATEGORIES };
00307 
00308 #ifdef __GTHREADS
00309     static __gthread_once_t _S_once;
00310 #endif
00311 
00312     explicit
00313     locale(_Impl*) throw();
00314 
00315     static void
00316     _S_initialize();
00317 
00318     static void
00319     _S_initialize_once() throw();
00320 
00321     static category
00322     _S_normalize_category(category);
00323 
00324     void
00325     _M_coalesce(const locale& __base, const locale& __add, category __cat);
00326   };
00327 
00328 
00329   // 22.1.1.1.2  Class locale::facet
00330   /**
00331    *  @brief  Localization functionality base class.
00332    *  @ingroup locales
00333    *
00334    *  The facet class is the base class for a localization feature, such as
00335    *  money, time, and number printing.  It provides common support for facets
00336    *  and reference management.
00337    *
00338    *  Facets may not be copied or assigned.
00339   */
00340   class locale::facet
00341   {
00342   private:
00343     friend class locale;
00344     friend class locale::_Impl;
00345 
00346     mutable _Atomic_word        _M_refcount;
00347 
00348     // Contains data from the underlying "C" library for the classic locale.
00349     static __c_locale                   _S_c_locale;
00350 
00351     // String literal for the name of the classic locale.
00352     static const char           _S_c_name[2];
00353 
00354 #ifdef __GTHREADS
00355     static __gthread_once_t     _S_once;
00356 #endif
00357 
00358     static void
00359     _S_initialize_once();
00360 
00361   protected:
00362     /**
00363      *  @brief  Facet constructor.
00364      *
00365      *  This is the constructor provided by the standard.  If refs is 0, the
00366      *  facet is destroyed when the last referencing locale is destroyed.
00367      *  Otherwise the facet will never be destroyed.
00368      *
00369      *  @param __refs  The initial value for reference count.
00370     */
00371     explicit
00372     facet(size_t __refs = 0) throw() : _M_refcount(__refs ? 1 : 0)
00373     { }
00374 
00375     /// Facet destructor.
00376     virtual
00377     ~facet();
00378 
00379     static void
00380     _S_create_c_locale(__c_locale& __cloc, const char* __s,
00381                __c_locale __old = 0);
00382 
00383     static __c_locale
00384     _S_clone_c_locale(__c_locale& __cloc) throw();
00385 
00386     static void
00387     _S_destroy_c_locale(__c_locale& __cloc);
00388 
00389     static __c_locale
00390     _S_lc_ctype_c_locale(__c_locale __cloc, const char* __s);
00391 
00392     // Returns data from the underlying "C" library data for the
00393     // classic locale.
00394     static __c_locale
00395     _S_get_c_locale();
00396 
00397     _GLIBCXX_CONST static const char*
00398     _S_get_c_name() throw();
00399 
00400   private:
00401     void
00402     _M_add_reference() const throw()
00403     { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
00404 
00405     void
00406     _M_remove_reference() const throw()
00407     {
00408       // Be race-detector-friendly.  For more info see bits/c++config.
00409       _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
00410       if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1) == 1)
00411     {
00412           _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
00413       __try
00414         { delete this; }
00415       __catch(...)
00416         { }
00417     }
00418     }
00419 
00420     facet(const facet&);  // Not defined.
00421 
00422     facet&
00423     operator=(const facet&);  // Not defined.
00424   };
00425 
00426 
00427   // 22.1.1.1.3 Class locale::id
00428   /**
00429    *  @brief  Facet ID class.
00430    *  @ingroup locales
00431    *
00432    *  The ID class provides facets with an index used to identify them.
00433    *  Every facet class must define a public static member locale::id, or be
00434    *  derived from a facet that provides this member, otherwise the facet
00435    *  cannot be used in a locale.  The locale::id ensures that each class
00436    *  type gets a unique identifier.
00437   */
00438   class locale::id
00439   {
00440   private:
00441     friend class locale;
00442     friend class locale::_Impl;
00443 
00444     template<typename _Facet>
00445       friend const _Facet&
00446       use_facet(const locale&);
00447 
00448     template<typename _Facet>
00449       friend bool
00450       has_facet(const locale&) throw();
00451 
00452     // NB: There is no accessor for _M_index because it may be used
00453     // before the constructor is run; the effect of calling a member
00454     // function (even an inline) would be undefined.
00455     mutable size_t      _M_index;
00456 
00457     // Last id number assigned.
00458     static _Atomic_word     _S_refcount;
00459 
00460     void
00461     operator=(const id&);  // Not defined.
00462 
00463     id(const id&);  // Not defined.
00464 
00465   public:
00466     // NB: This class is always a static data member, and thus can be
00467     // counted on to be zero-initialized.
00468     /// Constructor.
00469     id() { }
00470 
00471     size_t
00472     _M_id() const throw();
00473   };
00474 
00475 
00476   // Implementation object for locale.
00477   class locale::_Impl
00478   {
00479   public:
00480     // Friends.
00481     friend class locale;
00482     friend class locale::facet;
00483 
00484     template<typename _Facet>
00485       friend bool
00486       has_facet(const locale&) throw();
00487 
00488     template<typename _Facet>
00489       friend const _Facet&
00490       use_facet(const locale&);
00491 
00492     template<typename _Cache>
00493       friend struct __use_cache;
00494 
00495   private:
00496     // Data Members.
00497     _Atomic_word            _M_refcount;
00498     const facet**           _M_facets;
00499     size_t              _M_facets_size;
00500     const facet**           _M_caches;
00501     char**              _M_names;
00502     static const locale::id* const  _S_id_ctype[];
00503     static const locale::id* const  _S_id_numeric[];
00504     static const locale::id* const  _S_id_collate[];
00505     static const locale::id* const  _S_id_time[];
00506     static const locale::id* const  _S_id_monetary[];
00507     static const locale::id* const  _S_id_messages[];
00508     static const locale::id* const* const _S_facet_categories[];
00509 
00510     void
00511     _M_add_reference() throw()
00512     { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
00513 
00514     void
00515     _M_remove_reference() throw()
00516     {
00517       // Be race-detector-friendly.  For more info see bits/c++config.
00518       _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
00519       if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1) == 1)
00520     {
00521           _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
00522       __try
00523         { delete this; }
00524       __catch(...)
00525         { }
00526     }
00527     }
00528 
00529     _Impl(const _Impl&, size_t);
00530     _Impl(const char*, size_t);
00531     _Impl(size_t) throw();
00532 
00533    ~_Impl() throw();
00534 
00535     _Impl(const _Impl&);  // Not defined.
00536 
00537     void
00538     operator=(const _Impl&);  // Not defined.
00539 
00540     bool
00541     _M_check_same_name()
00542     {
00543       bool __ret = true;
00544       if (_M_names[1])
00545     // We must actually compare all the _M_names: can be all equal!
00546     for (size_t __i = 0; __ret && __i < _S_categories_size - 1; ++__i)
00547       __ret = __builtin_strcmp(_M_names[__i], _M_names[__i + 1]) == 0;
00548       return __ret;
00549     }
00550 
00551     void
00552     _M_replace_categories(const _Impl*, category);
00553 
00554     void
00555     _M_replace_category(const _Impl*, const locale::id* const*);
00556 
00557     void
00558     _M_replace_facet(const _Impl*, const locale::id*);
00559 
00560     void
00561     _M_install_facet(const locale::id*, const facet*);
00562 
00563     template<typename _Facet>
00564       void
00565       _M_init_facet(_Facet* __facet)
00566       { _M_install_facet(&_Facet::id, __facet); }
00567 
00568     void
00569     _M_install_cache(const facet*, size_t);
00570   };
00571 
00572 
00573   /**
00574    *  @brief  Facet for localized string comparison.
00575    *
00576    *  This facet encapsulates the code to compare strings in a localized
00577    *  manner.
00578    *
00579    *  The collate template uses protected virtual functions to provide
00580    *  the actual results.  The public accessors forward the call to
00581    *  the virtual functions.  These virtual functions are hooks for
00582    *  developers to implement the behavior they require from the
00583    *  collate facet.
00584   */
00585   template<typename _CharT>
00586     class collate : public locale::facet
00587     {
00588     public:
00589       // Types:
00590       //@{
00591       /// Public typedefs
00592       typedef _CharT            char_type;
00593       typedef basic_string<_CharT>  string_type;
00594       //@}
00595 
00596     protected:
00597       // Underlying "C" library locale information saved from
00598       // initialization, needed by collate_byname as well.
00599       __c_locale            _M_c_locale_collate;
00600 
00601     public:
00602       /// Numpunct facet id.
00603       static locale::id         id;
00604 
00605       /**
00606        *  @brief  Constructor performs initialization.
00607        *
00608        *  This is the constructor provided by the standard.
00609        *
00610        *  @param __refs  Passed to the base facet class.
00611       */
00612       explicit
00613       collate(size_t __refs = 0)
00614       : facet(__refs), _M_c_locale_collate(_S_get_c_locale())
00615       { }
00616 
00617       /**
00618        *  @brief  Internal constructor. Not for general use.
00619        *
00620        *  This is a constructor for use by the library itself to set up new
00621        *  locales.
00622        *
00623        *  @param __cloc  The C locale.
00624        *  @param __refs  Passed to the base facet class.
00625       */
00626       explicit
00627       collate(__c_locale __cloc, size_t __refs = 0)
00628       : facet(__refs), _M_c_locale_collate(_S_clone_c_locale(__cloc))
00629       { }
00630 
00631       /**
00632        *  @brief  Compare two strings.
00633        *
00634        *  This function compares two strings and returns the result by calling
00635        *  collate::do_compare().
00636        *
00637        *  @param __lo1  Start of string 1.
00638        *  @param __hi1  End of string 1.
00639        *  @param __lo2  Start of string 2.
00640        *  @param __hi2  End of string 2.
00641        *  @return  1 if string1 > string2, -1 if string1 < string2, else 0.
00642       */
00643       int
00644       compare(const _CharT* __lo1, const _CharT* __hi1,
00645           const _CharT* __lo2, const _CharT* __hi2) const
00646       { return this->do_compare(__lo1, __hi1, __lo2, __hi2); }
00647 
00648       /**
00649        *  @brief  Transform string to comparable form.
00650        *
00651        *  This function is a wrapper for strxfrm functionality.  It takes the
00652        *  input string and returns a modified string that can be directly
00653        *  compared to other transformed strings.  In the C locale, this
00654        *  function just returns a copy of the input string.  In some other
00655        *  locales, it may replace two chars with one, change a char for
00656        *  another, etc.  It does so by returning collate::do_transform().
00657        *
00658        *  @param __lo  Start of string.
00659        *  @param __hi  End of string.
00660        *  @return  Transformed string_type.
00661       */
00662       string_type
00663       transform(const _CharT* __lo, const _CharT* __hi) const
00664       { return this->do_transform(__lo, __hi); }
00665 
00666       /**
00667        *  @brief  Return hash of a string.
00668        *
00669        *  This function computes and returns a hash on the input string.  It
00670        *  does so by returning collate::do_hash().
00671        *
00672        *  @param __lo  Start of string.
00673        *  @param __hi  End of string.
00674        *  @return  Hash value.
00675       */
00676       long
00677       hash(const _CharT* __lo, const _CharT* __hi) const
00678       { return this->do_hash(__lo, __hi); }
00679 
00680       // Used to abstract out _CharT bits in virtual member functions, below.
00681       int
00682       _M_compare(const _CharT*, const _CharT*) const throw();
00683 
00684       size_t
00685       _M_transform(_CharT*, const _CharT*, size_t) const throw();
00686 
00687   protected:
00688       /// Destructor.
00689       virtual
00690       ~collate()
00691       { _S_destroy_c_locale(_M_c_locale_collate); }
00692 
00693       /**
00694        *  @brief  Compare two strings.
00695        *
00696        *  This function is a hook for derived classes to change the value
00697        *  returned.  @see compare().
00698        *
00699        *  @param __lo1  Start of string 1.
00700        *  @param __hi1  End of string 1.
00701        *  @param __lo2  Start of string 2.
00702        *  @param __hi2  End of string 2.
00703        *  @return  1 if string1 > string2, -1 if string1 < string2, else 0.
00704       */
00705       virtual int
00706       do_compare(const _CharT* __lo1, const _CharT* __hi1,
00707          const _CharT* __lo2, const _CharT* __hi2) const;
00708 
00709       /**
00710        *  @brief  Transform string to comparable form.
00711        *
00712        *  This function is a hook for derived classes to change the value
00713        *  returned.
00714        *
00715        *  @param __lo  Start.
00716        *  @param __hi  End.
00717        *  @return  transformed string.
00718       */
00719       virtual string_type
00720       do_transform(const _CharT* __lo, const _CharT* __hi) const;
00721 
00722       /**
00723        *  @brief  Return hash of a string.
00724        *
00725        *  This function computes and returns a hash on the input string.  This
00726        *  function is a hook for derived classes to change the value returned.
00727        *
00728        *  @param __lo  Start of string.
00729        *  @param __hi  End of string.
00730        *  @return  Hash value.
00731       */
00732       virtual long
00733       do_hash(const _CharT* __lo, const _CharT* __hi) const;
00734     };
00735 
00736   template<typename _CharT>
00737     locale::id collate<_CharT>::id;
00738 
00739   // Specializations.
00740   template<>
00741     int
00742     collate<char>::_M_compare(const char*, const char*) const throw();
00743 
00744   template<>
00745     size_t
00746     collate<char>::_M_transform(char*, const char*, size_t) const throw();
00747 
00748 #ifdef _GLIBCXX_USE_WCHAR_T
00749   template<>
00750     int
00751     collate<wchar_t>::_M_compare(const wchar_t*, const wchar_t*) const throw();
00752 
00753   template<>
00754     size_t
00755     collate<wchar_t>::_M_transform(wchar_t*, const wchar_t*, size_t) const throw();
00756 #endif
00757 
00758   /// class collate_byname [22.2.4.2].
00759   template<typename _CharT>
00760     class collate_byname : public collate<_CharT>
00761     {
00762     public:
00763       //@{
00764       /// Public typedefs
00765       typedef _CharT               char_type;
00766       typedef basic_string<_CharT> string_type;
00767       //@}
00768 
00769       explicit
00770       collate_byname(const char* __s, size_t __refs = 0)
00771       : collate<_CharT>(__refs)
00772       {
00773     if (__builtin_strcmp(__s, "C") != 0
00774         && __builtin_strcmp(__s, "POSIX") != 0)
00775       {
00776         this->_S_destroy_c_locale(this->_M_c_locale_collate);
00777         this->_S_create_c_locale(this->_M_c_locale_collate, __s);
00778       }
00779       }
00780 
00781     protected:
00782       virtual
00783       ~collate_byname() { }
00784     };
00785 
00786 _GLIBCXX_END_NAMESPACE_VERSION
00787 } // namespace
00788 
00789 # include <bits/locale_classes.tcc>
00790 
00791 #endif