标准库头文件 <locale>

namespace std {
 
    // locale ：
    class locale;
    template <class Facet> const Facet& use_facet(const locale&);
    template <class Facet> bool has_facet(const locale&) noexcept;
 
    // 便利接口：
    template <class charT> bool isspace (charT c, const locale& loc);
    template <class charT> bool isprint (charT c, const locale& loc);
    template <class charT> bool iscntrl (charT c, const locale& loc);
    template <class charT> bool isupper (charT c, const locale& loc);
    template <class charT> bool islower (charT c, const locale& loc);
    template <class charT> bool isalpha (charT c, const locale& loc);
    template <class charT> bool isdigit (charT c, const locale& loc);
    template <class charT> bool ispunct (charT c, const locale& loc);
    template <class charT> bool isxdigit(charT c, const locale& loc);
    template <class charT> bool isalnum (charT c, const locale& loc);
    template <class charT> bool isgraph (charT c, const locale& loc);
    template <class charT> charT toupper(charT c, const locale& loc);
    template <class charT> charT tolower(charT c, const locale& loc);
    template <class Codecvt, class Elem = wchar_t,
              class Wide_alloc = std::allocator<Elem>,
        class Byte_alloc = std::allocator<char> > class wstring_convert;
    template <class Codecvt, class Elem = wchar_t,
              class Tr = char_traits<Elem>> class wbuffer_convert;
 
    // 字符类型：
    class ctype_base;
    template <class charT> class ctype;
    template <>            class ctype<char>; // 特化
    template <class charT> class ctype_byname;
    class codecvt_base;
    template <class internT, class externT, class stateT> class codecvt;
    template <class internT, class externT, class stateT> class codecvt_byname;
 
    // 数值：
    template <class charT, class InputIterator = istreambuf_iterator<charT> > class num_get;
    template <class charT, class OutputIterator = osterambuf_iterator<charT> > class num_put;
    template <class charT> class numpunct;
    template <class charT> class numpunct_byname;
 
    // 校对：
    template <class charT> class collate;
    template <class charT> class collate_byname;
 
    // 日期与时间：
    class time_base;	
    template <class charT, class InputIterator = istreambuf_iterator<charT> >
        class time_get;	
    template <class charT, class InputIterator> = istreambuf_iterator<charT> >
        class time_get_byname;	
    template <class charT, class OutputIterator> = ostreambuf_iterator<charT> >
        class time_put;	
    template <class charT, class OutputIterator> = ostreambuf_iterator<charT> >
        class time_put_byname;	
 
    // 货币：	
    class money_base;	
    template <class charT, class InputIterator = istreambuf_iterator<charT> > > 
        class money_get;
    template <class charT, class OutputIterator = ostreambuf_iterator<charT> > > 
        class money_put;
    template <class charT, bool Intl = false> class moneypunct;
    template <class charT, bool Intl = false> class moneypunct_byname;
 
    // 消息获取：
    class messages_base;
    template <class charT> class messages;
    template <class charT> class messages_byname;
}

class locale
{
public:
    // types:
    class facet;
    class id;
    typedef int category;
    static const category // 此处所赋之值仅用于阐释
        none    = 0,
        collate = 0x010, 
        ctype   = 0x020,
        monetary= 0x040, 
        numeric = 0x080,
        time    = 0x100, 
        messages= 0x200,
        all = collate | ctype | monetary | numeric | time | messages;
 
    // 构造/复制/销毁：
    locale() noexcept;
    locale(const locale& other) noexcept;
    explicit locale(const char* std_name);
    explicit locale(const string& std_name);
    locale(const locale& other, const char* std_name, category);
    locale(const locale& other, const string& std_name, category);
    template <class Facet> locale(const locale& other, Facet* f);
    locale(const locale& other, const locale& one, category);
    ~locale();
 
    // 非虚函数
    const locale& operator=(const locale& other) noexcept;
    template <class Facet> locale combine(const locale& other) const;
 
    // locale 操作：
    basic_string<char>
    name() const;
    bool operator==(const locale& other) const;
    bool operator!=(const locale& other) const;
    template <class charT, class traits, class Allocator>
    bool operator()(const basic_string<charT,traits,Allocator>& s1,
                    const basic_string<charT,traits,Allocator>& s2) const;
 
    // 全局 locale 对象：
    static
    locale global(const locale&);
    static const locale& classic();
};

class ctype_base
{
public:
    typedef /*T*/ mask;
 
    // 数值仅为说明。
    static const mask space = 1 << 0;
    static const mask print = 1 << 1;
    static const mask cntrl = 1 << 2;
    static const mask upper = 1 << 3;
    static const mask lower = 1 << 4;
    static const mask alpha = 1 << 5;
    static const mask digit = 1 << 6;
    static const mask punct = 1 << 7;
    static const mask xdigit= 1 << 8;
    static const mask blank = 1 << 9;
    static const mask alnum = alpha | digit;
    static const mask graph = alnum | punct;
 
};

template <class charT>
class ctype : public locale::facet, public ctype_base
{
public:
    typedef charT char_type;
 
    explicit ctype(size_t refs = 0);
 
    bool is(mask m, charT c) const;
    const charT* is(const charT* low, const charT* high, mask* vec) const;
    const charT* scan_is(mask m,
                         const charT* low, const charT* high) const;
    const charT* scan_not(mask m,
                          const charT* low, const charT* high) const;
 
    charT           toupper(charT c) const;
    const charT*    toupper(charT* low, const charT* high) const;
    charT           tolower(charT c) const;
    const charT*    tolower(charT* low, const charT* high) const;
 
    charT       widen(char c) const;
    const char* widen(const char* low, const char* high, charT* to) const;
    char        narrow(charT c, char dfault) const;
    const charT*narrow(const charT* low, const charT*, char dfault,
                        char* to) const;
 
    static locale::id id;
 
protected:
    ~ctype();
    virtual bool do_is(mask m, charT c) const;
    virtual const charT* do_is(const charT* low, const charT* high,
                               mask* vec) const;
    virtual const charT* do_scan_is(mask m,
                                    const charT* low, const charT* high) const;
    virtual const charT* do_scan_not(mask m,
                                     const charT* low, const charT* high) const;
 
    virtual charT do_toupper(charT) const;
    virtual const charT* do_toupper(charT* low, const charT* high) const;
    virtual charT do_tolower(charT) const;
    virtual const charT* do_tolower(charT* low, const charT* high) const;
    virtual charT do_widen(char) const;
    virtual const char*  do_widen(const char* low, const char* high,
                                  charT* dest) const;
    virtual char do_narrow(charT, char dfault) const;
    virtual const charT* do_narrow(const charT* low, const charT* high,
                                   char dfault, char* dest) const;
};

template <class charT>
class ctype_byname : public ctype<charT>
{
public:
    typedef typename ctype<charT>::mask mask;
    explicit ctype_byname(const char*, size_t refs = 0);
    explicit ctype_byname(const string&, size_t refs = 0);
    protected:
    ~ctype_byname();
};

template <> class ctype<char>
    : public locale::facet, public ctype_base
{
public:
    typedef char char_type;
    explicit ctype(const mask* tab = 0, bool del = false,
                   size_t refs = 0);
    bool is(mask m, char c) const;
    const char* is(const char* low, const char* high, mask* vec) const;
    const char* scan_is (mask m,
                         const char* low, const char* high) const;
    const char* scan_not(mask m,
                         const char* low, const char* high) const;
    char        toupper(char c) const;
    const char* toupper(char* low, const char* high) const;
    char        tolower(char c) const;
    const char* tolower(char* low, const char* high) const;
    char        widen(char c) const;
    const char* widen(const char* low, const char* high, char* to) const;
    char        narrow(char c, char dfault) const;
    const char* narrow(const char* low, const char* high, char dfault,
                       char* to) const;
 
    static locale::id id;
 
    static const size_t table_size = implementation-defined;
    const mask* table() const noexcept;
    static const mask* classic_table() noexcept;
 
protected:
    ~ctype();
    virtual char        do_toupper(char c) const;
    virtual const char* do_toupper(char* low, const char* high) const;
    virtual char        do_tolower(char c) const;
    virtual const char* do_tolower(char* low, const char* high) const;
    virtual char        do_widen(char c) const;
    virtual const char* do_widen(const char* low,
                                 const char* high,
                                 char* to) const;
    virtual char        do_narrow(char c, char dfault) const;
    virtual const char* do_narrow(const char* low,
                                  const char* high,
                                  char dfault, char* to) const;
};

class codecvt_base
{
public:
    enum result { ok, partial, error, noconv };
};

template <class internT, class externT, class stateT>
class codecvt : public locale::facet, public codecvt_base
{
public:
        typedef internT intern_type;
        typedef externT extern_type;
        typedef stateT state_type;
        explicit codecvt(size_t refs = 0);
        result out(stateT& state,
                   const internT* from, const internT* from_end, 
                   const internT*& from_next,
                   externT* to, externT* to_end, externT*& to_next) const;
        result unshift(stateT& state, externT* to,
                       externT* to_end, externT*& to_next) const;
        result in(stateT& state,
                  const externT* from, const externT* from_end, 
                  const externT*& from_next,
                  internT* to,
                  internT* to_end, internT*& to_next) const;
        int encoding() const noexcept;
        bool always_noconv() const noexcept;
        int length(stateT&, const externT* from, const externT* end,
                   size_t max) const;
        int max_length() const noexcept;
        static locale::id id;
protected:
        ~codecvt();
        virtual result do_out(stateT& state,
                              const internT* from, const internT* from_end, 
                              const internT*& from_next,
                              externT* to,
                              externT* to_end, externT*& to_next) const;
        virtual result do_in(stateT& state,
                             const externT* from, const externT* from_end, 
                             const externT*& from_next,
                             internT* to,
                             internT* to_end, internT*& to_next) const;
        virtual result do_unshift(stateT& state,
                                  externT* to,
                                  externT* to_end, externT*& to_next) const;
        virtual int do_encoding() const noexcept;
        virtual bool do_always_noconv() const noexcept;
        virtual int do_length(stateT&, const externT* from,
                              const externT* end, size_t max) const;
        virtual int do_max_length() const noexcept;
};

template <class internT, class externT, class stateT>
class codecvt_byname : public codecvt<internT, externT, stateT>
{
public:
    explicit codecvt_byname(const char*, size_t refs = 0);
    explicit codecvt_byname(const string&, size_t refs = 0);
protected:
    ~codecvt_byname();
};

template <class charT, class InputIterator = istreambuf_iterator<charT> >
class num_get : public locale::facet
{
public:
    typedef charT           char_type;
    typedef InputIterator   iter_type;
    explicit num_get(size_t refs = 0);
    iter_type get(iter_type in, iter_type end, ios_base&,
                  ios_base::iostate& err, bool& v) const;
    iter_type get(iter_type in, iter_type end, ios_base& ,
                  ios_base::iostate& err, long& v) const;
    iter_type get(iter_type in, iter_type end, ios_base& ,
                  ios_base::iostate& err, long long& v) const;
    iter_type get(iter_type in, iter_type end, ios_base&,
                  ios_base::iostate& err, unsigned short& v) const;
    iter_type get(iter_type in, iter_type end, ios_base&,
                  ios_base::iostate& err, unsigned int& v) const;
    iter_type get(iter_type in, iter_type end, ios_base&,
                  ios_base::iostate& err, unsigned long& v) const;
    iter_type get(iter_type in, iter_type end, ios_base& ,
                  ios_base::iostate& err, unsigned long long& v) const;
    iter_type get(iter_type in, iter_type end, ios_base&,
                  ios_base::iostate& err, float& v) const;
    iter_type get(iter_type in, iter_type end, ios_base&,
                  ios_base::iostate& err, double& v) const;
    iter_type get(iter_type in, iter_type end, ios_base&,
                  ios_base::iostate& err, long double& v) const;
    iter_type get(iter_type in, iter_type end, ios_base&,
                  ios_base::iostate& err, void*& v) const;
 
    static locale::id id;
 
 
protected:
    ~num_get();
 
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, bool& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, long& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, long long& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, unsigned short& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, unsigned int& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, unsigned long& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, unsigned long long& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, float& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, double& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, long double& v) const;
    virtual iter_type do_get(iter_type, iter_type, ios_base&,
                             ios_base::iostate& err, void*& v) const;
};

template <class CharT, class OutputIterator = ostreambuf_iterator<CharT> >
class num_put : public locale::facet
{
public:
    typedef CharT char_type;
    typedef OutputIterator iter_type;
 
    explicit num_put(size_t refs = 0);
 
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  bool v) const;
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  long v) const;
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  long long v) const;
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  unsigned long v) const;
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  unsigned long long v) const;
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  double v) const;
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  long double v) const;
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  const void* v) const;
 
    static locale::id id;
 
protected:
    ~num_put();
 
    virtual iter_type do_put(iter_type, ios_base&, char_type fill,
                             bool v) const;
    virtual iter_type do_put(iter_type, ios_base&, char_type fill,
                             long v) const;
    virtual iter_type do_put(iter_type, ios_base&, char_type fill,
                             long long v) const;
    virtual iter_type do_put(iter_type, ios_base&, char_type fill,
                             unsigned long) const;
    virtual iter_type do_put(iter_type, ios_base&, char_type fill,
                             unsigned long long) const;
    virtual iter_type do_put(iter_type, ios_base&, char_type fill,
                             double v) const;
    virtual iter_type do_put(iter_type, ios_base&, char_type fill,
                             long double v) const;
    virtual iter_type do_put(iter_type, ios_base&, char_type fill,
                             const void* v) const;
};

template <class CharT>
class numpunct : public locale::facet
{
public:
    typedef CharT char_type;
    typedef basic_string<CharT> string_type;
 
    explicit numpunct(size_t refs = 0);
 
    char_type   decimal_point() const;
    char_type   thousands_sep() const;
    string      grouping()      const;
    string_type truename()      const;
    string_type falsename()     const;
 
    static locale::id id;
 
protected:
    ~numpunct(); // 虚函数
 
    virtual char_type   do_decimal_point() const;
    virtual char_type   do_thousands_sep() const;
    virtual string      do_grouping()      const;
    virtual string_type do_truename()      const; // 对于 bool
    virtual string_type do_falsename()     const; // 对于 bool
};

template <class CharT>
class numpunct_byname : public numpunct<CharT>
{
public:
    typedef CharT char_type;
    typedef basic_string<CharT> string_type;
 
    explicit numpunct_byname(const char*, size_t refs = 0);
    explicit numpunct_byname(const string&, size_t refs = 0);
 
protected:
    ~numpunct_byname();
};

template <class CharT>
class collate : public locale::facet
{
public:
    typedef CharT char_type;
    typedef basic_string<CharT> string_type;
 
    explicit collate(size_t refs = 0);
 
    int compare(const CharT* low1, const CharT* high1,
                const CharT* low2, const CharT* high2) const;
    string_type transform(const CharT* low, const CharT* high) const;
    long hash(const CharT* low, const CharT* high) const;
 
    static locale::id id;
 
protected:
    ~collate();
 
    virtual int do_compare(const CharT* low1, const CharT* high1,
                           const CharT* low2, const CharT* high2) const;
    virtual string_type do_transform(const CharT* low,
                                     const CharT* high) const;
    virtual long do_hash (const CharT* low, const CharT* high) const;
};

template <class CharT>
class collate_byname : public collate<CharT>
{
public:
    typedef basic_string<CharT> string_type;
 
    explicit collate_byname(const char*, size_t refs = 0);
    explicit collate_byname(const string&, size_t refs = 0);
 
protected:
    ~collate_byname();
};

class time_base
{
public:
    enum dateorder { no_order, dmy, mdy, ymd, ydm };
};

template <class CharT, class InputIterator = istreambuf_iterator<CharT> >
class time_get : public locale::facet, public time_base
{
public:
    typedef CharT char_type;
    typedef InputIterator iter_type;
 
    explicit time_get(size_t refs = 0);
 
    dateorder date_order() const;
    iter_type get_time(iter_type s, iter_type end, ios_base& f,
                       ios_base::iostate& err, tm* t) const;
    iter_type get_date(iter_type s, iter_type end, ios_base& f,
                       ios_base::iostate& err, tm* t) const;
    iter_type get_weekday(iter_type s, iter_type end, ios_base& f,
                          ios_base::iostate& err, tm* t) const;
    iter_type get_monthname(iter_type s, iter_type end, ios_base& f,
                            ios_base::iostate& err, tm* t) const;
    iter_type get_year(iter_type s, iter_type end, ios_base& f,
                       ios_base::iostate& err, tm* t) const;
    iter_type get(iter_type s, iter_type end, ios_base& f,
                  ios_base::iostate& err, tm* t, char format,
                  char modifier = 0) const;
    iter_type get(iter_type s, iter_type end, ios_base& f,
                  ios_base::iostate& err, tm* t,
                  const char_type* fmt, const char_type* fmtend) const;
 
    static locale::id id;
 
protected:
    ~time_get();
 
    virtual dateorder do_date_order() const;
    virtual iter_type do_get_time(iter_type s, iter_type end, ios_base&,
                                  ios_base::iostate& err, tm* t) const;
    virtual iter_type do_get_date(iter_type s, iter_type end, ios_base&,
                                  ios_base::iostate& err, tm* t) const;
    virtual iter_type do_get_weekday(iter_type s, iter_type end, ios_base&,
                                     ios_base::iostate& err, tm* t) const;
    virtual iter_type do_get_monthname(iter_type s, iter_type end, ios_base&,
                                       ios_base::iostate& err, tm* t) const;
    virtual iter_type do_get_year(iter_type s, iter_type end, ios_base&,
                                  ios_base::iostate& err, tm* t) const;
    virtual iter_type do_get(iter_type s, iter_type end, ios_base& f,
                             ios_base::iostate& err, tm* t,
                             char format, char modifier) const;
};

template <class CharT, class InputIterator = istreambuf_iterator<CharT> >
class time_get_byname : public time_get<CharT, InputIterator>
{
public:
    typedef time_base::dateorder dateorder;
    typedef InputIterator iter_type;
 
    explicit time_get_byname(const char*, size_t refs = 0);
    explicit time_get_byname(const string&, size_t refs = 0);
 
protected:
    ~time_get_byname();
};

template <class CharT, class OutputIterator = ostreambuf_iterator<CharT> >
class time_put : public locale::facet
{
public:
    typedef CharT char_type;
    typedef OutputIterator iter_type;
 
    explicit time_put(size_t refs = 0);
 
    // 下列函数以其他成员函数实现。
    iter_type put(iter_type s, ios_base& f, char_type fill, const tm* tmb,
                  const CharT* pattern, const CharT* pat_end) const;
    iter_type put(iter_type s, ios_base& f, char_type fill,
                  const tm* tmb, char format, char modifier = 0) const;
 
    static locale::id id;
 
protected:
    ~time_put();
 
    virtual iter_type do_put(iter_type s, ios_base&, char_type, const tm* t,
                             char format, char modifier) const;
};

template <class CharT, class OutputIterator = ostreambuf_iterator<CharT> >
class time_put_byname : public time_put<CharT, OutputIterator>
{
public:
    typedef CharT char_type;
    typedef OutputIterator iter_type;
 
    explicit time_put_byname(const char*, size_t refs = 0);
    explicit time_put_byname(const string&, size_t refs = 0);
 
protected:
    ~time_put_byname();
};

template <class CharT, class InputIterator = istreambuf_iterator<CharT> >
class money_get : public locale::facet
{
public:
    typedef CharT char_type;
    typedef InputIterator iter_type;
    typedef basic_string<CharT> string_type;
 
    explicit money_get(size_t refs = 0);
 
    iter_type get(iter_type s, iter_type end, bool intl, ios_base& f,
                  ios_base::iostate& err, long double& units) const;
    iter_type get(iter_type s, iter_type end, bool intl, ios_base& f,
                  ios_base::iostate& err, string_type& digits) const;
 
    static locale::id id;
 
protected:
    ~money_get();
 
    virtual iter_type do_get(iter_type, iter_type, bool, ios_base&,
                             ios_base::iostate& err,
                             long double& units) const;
    virtual iter_type do_get(iter_type, iter_type, bool, ios_base&,
                             ios_base::iostate& err,
                             string_type& digits) const;
};

template <class CharT, class OutputIterator = ostreambuf_iterator<CharT> >
class money_put : public locale::facet
{
public:
    typedef CharT char_type;
    typedef OutputIterator iter_type;
    typedef basic_string<CharT> string_type;
 
    explicit money_put(size_t refs = 0);
 
    iter_type put(iter_type s, bool intl, ios_base& f,
                  char_type fill, long double units) const;
    iter_type put(iter_type s, bool intl, ios_base& f,
                  char_type fill, const string_type& digits) const;
 
    static locale::id id;
 
protected:
    ~money_put();
 
    virtual iter_type do_put(iter_type, bool, ios_base&, char_type fill,
                             long double units) const;
    virtual iter_type do_put(iter_type, bool, ios_base&, char_type fill,
                             const string_type& digits) const;
};

class money_base
{
public:
    enum part { none, space, symbol, sign, value };
    struct pattern { char field[4]; };
};

template <class CharT, bool International = false>
class moneypunct : public locale::facet, public money_base
{
public:
    typedef CharT char_type;
    typedef basic_string<CharT> string_type;
 
    explicit moneypunct(size_t refs = 0);
 
    CharT       decimal_point() const;
    CharT       thousands_sep() const;
    string      grouping()      const;
    string_type curr_symbol()   const;
    string_type positive_sign() const;
    string_type negative_sign() const;
    int         frac_digits()   const;
    pattern     pos_format()    const;
    pattern     neg_format()    const;
 
    static locale::id id;
    static const bool intl = International;
 
protected:
    ~moneypunct();
 
    virtual CharT       do_decimal_point() const;
    virtual CharT       do_thousands_sep() const;
    virtual string      do_grouping()      const;
    virtual string_type do_curr_symbol()   const;
    virtual string_type do_positive_sign() const;
    virtual string_type do_negative_sign() const;
    virtual int         do_frac_digits()   const;
    virtual pattern     do_pos_format()    const;
    virtual pattern     do_neg_format()    const;
};

template <class CharT, bool Intl = false>
class moneypunct_byname : public moneypunct<CharT, Intl>
{
public:
    typedef money_base::pattern pattern;
    typedef basic_string<CharT> string_type;
 
    explicit moneypunct_byname(const char*, size_t refs = 0);
    explicit moneypunct_byname(const string&, size_t refs = 0);
 
protected:
    ~moneypunct_byname();
};

class messages_base
{
public:
    typedef /* 未指明的有符号整数类型 */ catalog;
};

template <class CharT>
class messages : public locale::facet, public messages_base {
public:
    typedef CharT char_type;
    typedef basic_string<CharT> string_type;
 
    explicit messages(size_t refs = 0);
 
    catalog open(const basic_string<char>& fn, const locale&) const;
    string_type get(catalog c, int set, int msgid,
                    const string_type& dfault) const;
    void close(catalog c) const;
 
    static locale::id id;
 
protected:
    ~messages();
 
    virtual catalog do_open(const basic_string<char>&, const locale&) const;
    virtual string_type do_get(catalog, int set, int msgid,
                               const string_type& dfault) const;
    virtual void do_close(catalog) const;
};

template <class CharT>
class messages_byname : public messages<CharT>
{
public:
    typedef messages_base::catalog catalog;
    typedef basic_string<CharT> string_type;
 
    explicit messages_byname(const char*, size_t refs = 0);
    explicit messages_byname(const string&, size_t refs = 0);
 
protected:
    ~messages_byname();
};

template<class Codecvt, class Elem = wchar_t,
    class Wide_alloc = std::allocator<Elem>,
    class Byte_alloc = std::allocator<char> >
class wstring_convert
{
public:
    typedef std::basic_string<char, char_traits<char>, Byte_alloc> byte_string;
    typedef std::basic_string<Elem, char_traits<Elem>, Wide_alloc> wide_string;
    typedef typename Codecvt::state_type state_type;
    typedef typename wide_string::traits_type::int_type int_type;
 
    explicit wstring_convert(Codecvt* pcvt = new Codecvt);
    wstring_convert(Codecvt* pcvt, state_type state);
    explicit wstring_convert(const byte_string& byte_err,
                             const wide_string& wide_err = wide_string());
    ~wstring_convert();
 
    wstring_convert(const wstring_convert&) = delete;
    wstring_convert& operator=(const wstring_convert&) = delete;
 
    wide_string from_bytes(char byte);
    wide_string from_bytes(const char* ptr);
    wide_string from_bytes(const byte_string& str);
    wide_string from_bytes(const char* first, const char* last);
    byte_string to_bytes(Elem wchar);
    byte_string to_bytes(const Elem* wptr);
    byte_string to_bytes(const wide_string& wstr);
    byte_string to_bytes(const Elem* first, const Elem* last);
    size_t converted() const noexcept;
    state_type state() const;
 
private:
    byte_string byte_err_string; // 仅用于阐释
    wide_string wide_err_string; // 仅用于阐释
    Codecvt* cvtptr;             // 仅用于阐释
    state_type cvtstate;         // 仅用于阐释
    size_t cvtcount;             // 仅用于阐释
};

template<class Codecvt,
    class Elem = wchar_t,
    class Tr = std::char_traits<Elem> >
class wbuffer_convert : public std::basic_streambuf<Elem, Tr>
{
public:
    typedef typename Codecvt::state_type state_type;
 
    explicit wbuffer_convert(std::streambuf* bytebuf = 0,
                             Codecvt* pcvt = new Codecvt,
                             state_type state = state_type());
    ~wbuffer_convert();
 
    wbuffer_convert(const wbuffer_convert&) = delete;
    wbuffer_convert& operator=(const wbuffer_convert&) = delete;
 
    std::streambuf* rdbuf() const;
    std::streambuf* rdbuf(std::streambuf* bytebuf);
    state_type state() const;
private:
    std::streambuf* bufptr; // 仅用于阐释
    Codecvt* cvtptr;        // 仅用于阐释
    state_type cvtstate;    // 仅用于阐释
};