# codecvt_specializations.h

    00001 // Locale support (codecvt) -*- C++ -*-
    00002
    00003 // Copyright (C) 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
    00004 //
    00005 // This file is part of the GNU ISO C++ Library.  This library is free
    00006 // software; you can redistribute it and/or modify it under the
    00007 // terms of the GNU General Public License as published by the
    00008 // Free Software Foundation; either version 2, or (at your option)
    00009 // any later version.
    00010
    00011 // This library is distributed in the hope that it will be useful,
    00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00014 // GNU General Public License for more details.
    00015
    00016 // You should have received a copy of the GNU General Public License along
    00017 // with this library; see the file COPYING.  If not, write to the Free
    00018 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    00019 // USA.
    00020
    00021 // As a special exception, you may use this file as part of a free software
    00022 // library without restriction.  Specifically, if other files instantiate
    00023 // templates or use macros or inline functions from this file, or you compile
    00024 // this file and link it with other files to produce an executable, this
    00025 // file does not by itself cause the resulting executable to be covered by
    00026 // the GNU General Public License.  This exception does not however
    00027 // invalidate any other reasons why the executable file might be covered by
    00028 // the GNU General Public License.
    00029
    00030 //
    00031 // ISO C++ 14882: 22.2.1.5 Template class codecvt
    00032 //
    00033
    00034 // Warning: this file is not meant for user inclusion.  Use <locale>.
    00035
    00036 // Written by Benjamin Kosnik <bkoz@cygnus.com>
    00037
    00038   // XXX
    00039   // Define this here so codecvt.cc can have _S_max_size definition.
    00040 #define _GLIBCXX_USE___ENC_TRAITS 1
    00041
    00042   // Extension to use icov for dealing with character encodings,
    00043   // including conversions and comparisons between various character
    00044   // sets.  This object encapsulates data that may need to be shared between
    00045   // char_traits, codecvt and ctype.
    00046   class __enc_traits
    00047   {
    00048   public:
    00049     // Types:
    00050     // NB: A conversion descriptor subsumes and enhances the
    00051     // functionality of a simple state type such as mbstate_t.
    00052     typedef iconv_t __desc_type;
    00053
    00054   protected:
    00055     // Data Members:
    00056     // Max size of charset encoding name
    00057     static const int    _S_max_size = 32;
    00058     // Name of internal character set encoding.
    00059     char            _M_int_enc[_S_max_size];
    00060     // Name of external character set encoding.
    00061     char            _M_ext_enc[_S_max_size];
    00062
    00063     // Conversion descriptor between external encoding to internal encoding.
    00064     __desc_type     _M_in_desc;
    00065     // Conversion descriptor between internal encoding to external encoding.
    00066     __desc_type     _M_out_desc;
    00067
    00068     // Details the byte-order marker for the external encoding, if necessary.
    00069     int         _M_ext_bom;
    00070
    00071     // Details the byte-order marker for the internal encoding, if necessary.
    00072     int         _M_int_bom;
    00073
    00074   public:
    00075     explicit __enc_traits()
    00076     : _M_in_desc(0), _M_out_desc(0), _M_ext_bom(0), _M_int_bom(0)
    00077     {
    00078       memset(_M_int_enc, 0, _S_max_size);
    00079       memset(_M_ext_enc, 0, _S_max_size);
    00080     }
    00081
    00082     explicit __enc_traits(const char* __int, const char* __ext,
    00083               int __ibom = 0, int __ebom = 0)
    00084     : _M_in_desc(0), _M_out_desc(0), _M_ext_bom(__ebom), _M_int_bom(__ibom)
    00085     {
    00086       strncpy(_M_int_enc, __int, _S_max_size);
    00087       strncpy(_M_ext_enc, __ext, _S_max_size);
    00088       _M_init();
    00089     }
    00090
    00091     // 21.1.2 traits typedefs
    00092     // p4
    00093     // typedef STATE_T state_type
    00094     // requires: state_type shall meet the requirements of
    00095     // CopyConstructible types (20.1.3)
    00096     // NB: This does not preseve the actual state of the conversion
    00097     // descriptor member, but it does duplicate the encoding
    00098     // information.
    00099     __enc_traits(const __enc_traits& __obj): _M_in_desc(0), _M_out_desc(0)
    00100     {
    00101       strncpy(_M_int_enc, __obj._M_int_enc, _S_max_size);
    00102       strncpy(_M_ext_enc, __obj._M_ext_enc, _S_max_size);
    00103       _M_ext_bom = __obj._M_ext_bom;
    00104       _M_int_bom = __obj._M_int_bom;
    00105       _M_destroy();
    00106       _M_init();
    00107     }
    00108
    00109     // Need assignment operator as well.
    00110     __enc_traits&
    00111     operator=(const __enc_traits& __obj)
    00112     {
    00113       strncpy(_M_int_enc, __obj._M_int_enc, _S_max_size);
    00114       strncpy(_M_ext_enc, __obj._M_ext_enc, _S_max_size);
    00115       _M_ext_bom = __obj._M_ext_bom;
    00116       _M_int_bom = __obj._M_int_bom;
    00117       _M_destroy();
    00118       _M_init();
    00119       return *this;
    00120     }
    00121
    00122     ~__enc_traits()
    00123     { _M_destroy(); }
    00124
    00125     void
    00126     _M_init()
    00127     {
    00128       const __desc_type __err = reinterpret_cast<iconv_t>(-1);
    00129       if (!_M_in_desc)
    00130     {
    00131       _M_in_desc = iconv_open(_M_int_enc, _M_ext_enc);
    00132       if (_M_in_desc == __err)
    00133         __throw_runtime_error(__N("__enc_traits::_M_init "
    00134                   "creating iconv input descriptor failed"));
    00135     }
    00136       if (!_M_out_desc)
    00137     {
    00138       _M_out_desc = iconv_open(_M_ext_enc, _M_int_enc);
    00139       if (_M_out_desc == __err)
    00140         __throw_runtime_error(__N("__enc_traits::_M_init "
    00141                   "creating iconv output descriptor failed"));
    00142     }
    00143     }
    00144
    00145     void
    00146     _M_destroy()
    00147     {
    00148       const __desc_type __err = reinterpret_cast<iconv_t>(-1);
    00149       if (_M_in_desc && _M_in_desc != __err)
    00150     {
    00151       iconv_close(_M_in_desc);
    00152       _M_in_desc = 0;
    00153     }
    00154       if (_M_out_desc && _M_out_desc != __err)
    00155     {
    00156       iconv_close(_M_out_desc);
    00157       _M_out_desc = 0;
    00158     }
    00159     }
    00160
    00161     bool
    00162     _M_good()
    00163     {
    00164       const __desc_type __err = reinterpret_cast<iconv_t>(-1);
    00165       bool __test = _M_in_desc && _M_in_desc != __err;
    00166       __test &=  _M_out_desc && _M_out_desc != __err;
    00167       return __test;
    00168     }
    00169
    00170     const __desc_type*
    00171     _M_get_in_descriptor()
    00172     { return &_M_in_desc; }
    00173
    00174     const __desc_type*
    00175     _M_get_out_descriptor()
    00176     { return &_M_out_desc; }
    00177
    00178     int
    00179     _M_get_external_bom()
    00180     { return _M_ext_bom; }
    00181
    00182     int
    00183     _M_get_internal_bom()
    00184     { return _M_int_bom; }
    00185
    00186     const char*
    00187     _M_get_internal_enc()
    00188     { return _M_int_enc; }
    00189
    00190     const char*
    00191     _M_get_external_enc()
    00192     { return _M_ext_enc; }
    00193   };
    00194
    00195   // Partial specialization
    00196   // This specialization takes advantage of iconv to provide code
    00197   // conversions between a large number of character encodings.
    00198   template<typename _InternT, typename _ExternT>
    00199     class codecvt<_InternT, _ExternT, __enc_traits>
    00200     : public __codecvt_abstract_base<_InternT, _ExternT, __enc_traits>
    00201     {
    00202     public:
    00203       // Types:
    00204       typedef codecvt_base::result          result;
    00205       typedef _InternT                  intern_type;
    00206       typedef _ExternT                  extern_type;
    00207       typedef __enc_traits              state_type;
    00208       typedef __enc_traits::__desc_type         __desc_type;
    00209       typedef __enc_traits              __enc_type;
    00210
    00211       // Data Members:
    00212       static locale::id         id;
    00213
    00214       explicit
    00215       codecvt(size_t __refs = 0)
    00216       : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
    00217       { }
    00218
    00219       explicit
    00220       codecvt(__enc_type* __enc, size_t __refs = 0)
    00221       : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
    00222       { }
    00223
    00224     protected:
    00225       virtual
    00226       ~codecvt() { }
    00227
    00228       virtual result
    00229       do_out(state_type& __state, const intern_type* __from,
    00230          const intern_type* __from_end, const intern_type*& __from_next,
    00231          extern_type* __to, extern_type* __to_end,
    00232          extern_type*& __to_next) const;
    00233
    00234       virtual result
    00235       do_unshift(state_type& __state, extern_type* __to,
    00236          extern_type* __to_end, extern_type*& __to_next) const;
    00237
    00238       virtual result
    00239       do_in(state_type& __state, const extern_type* __from,
    00240         const extern_type* __from_end, const extern_type*& __from_next,
    00241         intern_type* __to, intern_type* __to_end,
    00242         intern_type*& __to_next) const;
    00243
    00244       virtual int
    00245       do_encoding() const throw();
    00246
    00247       virtual bool
    00248       do_always_noconv() const throw();
    00249
    00250       virtual int
    00251       do_length(state_type&, const extern_type* __from,
    00252         const extern_type* __end, size_t __max) const;
    00253
    00254       virtual int
    00255       do_max_length() const throw();
    00256     };
    00257
    00258   template<typename _InternT, typename _ExternT>
    00259     locale::id
    00260     codecvt<_InternT, _ExternT, __enc_traits>::id;
    00261
    00262   // This adaptor works around the signature problems of the second
    00263   // argument to iconv():  SUSv2 and others use 'const char**', but glibc 2.2
    00264   // uses 'char**', which matches the POSIX 1003.1-2001 standard.
    00265   // Using this adaptor, g++ will do the work for us.
    00266   template<typename _T>
    00267     inline size_t
    00268     __iconv_adaptor(size_t(*__func)(iconv_t, _T, size_t*, char**, size_t*),
    00269                     iconv_t __cd, char** __inbuf, size_t* __inbytes,
    00270                     char** __outbuf, size_t* __outbytes)
    00271     { return __func(__cd, (_T)__inbuf, __inbytes, __outbuf, __outbytes); }
    00272
    00273   template<typename _InternT, typename _ExternT>
    00274     codecvt_base::result
    00275     codecvt<_InternT, _ExternT, __enc_traits>::
    00276     do_out(state_type& __state, const intern_type* __from,
    00277        const intern_type* __from_end, const intern_type*& __from_next,
    00278        extern_type* __to, extern_type* __to_end,
    00279        extern_type*& __to_next) const
    00280     {
    00281       result __ret = codecvt_base::error;
    00282       if (__state._M_good())
    00283     {
    00284       typedef state_type::__desc_type   __desc_type;
    00285       const __desc_type* __desc = __state._M_get_out_descriptor();
    00286       const size_t __fmultiple = sizeof(intern_type);
    00287       size_t __fbytes = __fmultiple * (__from_end - __from);
    00288       const size_t __tmultiple = sizeof(extern_type);
    00289       size_t __tbytes = __tmultiple * (__to_end - __to);
    00290
    00291       // Argument list for iconv specifies a byte sequence. Thus,
    00292       // all to/from arrays must be brutally casted to char*.
    00293       char* __cto = reinterpret_cast<char*>(__to);
    00294       char* __cfrom;
    00295       size_t __conv;
    00296
    00297       // Some encodings need a byte order marker as the first item
    00298       // in the byte stream, to designate endian-ness. The default
    00299       // value for the byte order marker is NULL, so if this is
    00300       // the case, it's not necessary and we can just go on our
    00301       // merry way.
    00302       int __int_bom = __state._M_get_internal_bom();
    00303       if (__int_bom)
    00304         {
    00305           size_t __size = __from_end - __from;
    00306           intern_type* __cfixed = static_cast<intern_type*>(__builtin_alloca(sizeof(intern_type) * (__size + 1)));
    00307           __cfixed[0] = static_cast<intern_type>(__int_bom);
    00308           char_traits<intern_type>::copy(__cfixed + 1, __from, __size);
    00309           __cfrom = reinterpret_cast<char*>(__cfixed);
    00310           __conv = __iconv_adaptor(iconv, *__desc, &__cfrom,
    00311                                         &__fbytes, &__cto, &__tbytes);
    00312         }
    00313       else
    00314         {
    00315           intern_type* __cfixed = const_cast<intern_type*>(__from);
    00316           __cfrom = reinterpret_cast<char*>(__cfixed);
    00317           __conv = __iconv_adaptor(iconv, *__desc, &__cfrom, &__fbytes,
    00318                        &__cto, &__tbytes);
    00319         }
    00320
    00321       if (__conv != size_t(-1))
    00322         {
    00323           __from_next = reinterpret_cast<const intern_type*>(__cfrom);
    00324           __to_next = reinterpret_cast<extern_type*>(__cto);
    00325           __ret = codecvt_base::ok;
    00326         }
    00327       else
    00328         {
    00329           if (__fbytes < __fmultiple * (__from_end - __from))
    00330         {
    00331           __from_next = reinterpret_cast<const intern_type*>(__cfrom);
    00332           __to_next = reinterpret_cast<extern_type*>(__cto);
    00333           __ret = codecvt_base::partial;
    00334         }
    00335           else
    00336         __ret = codecvt_base::error;
    00337         }
    00338     }
    00339       return __ret;
    00340     }
    00341
    00342   template<typename _InternT, typename _ExternT>
    00343     codecvt_base::result
    00344     codecvt<_InternT, _ExternT, __enc_traits>::
    00345     do_unshift(state_type& __state, extern_type* __to,
    00346            extern_type* __to_end, extern_type*& __to_next) const
    00347     {
    00348       result __ret = codecvt_base::error;
    00349       if (__state._M_good())
    00350     {
    00351       typedef state_type::__desc_type   __desc_type;
    00352       const __desc_type* __desc = __state._M_get_in_descriptor();
    00353       const size_t __tmultiple = sizeof(intern_type);
    00354       size_t __tlen = __tmultiple * (__to_end - __to);
    00355
    00356       // Argument list for iconv specifies a byte sequence. Thus,
    00357       // all to/from arrays must be brutally casted to char*.
    00358       char* __cto = reinterpret_cast<char*>(__to);
    00359       size_t __conv = __iconv_adaptor(iconv,*__desc, NULL, NULL,
    00360                                           &__cto, &__tlen);
    00361
    00362       if (__conv != size_t(-1))
    00363         {
    00364           __to_next = reinterpret_cast<extern_type*>(__cto);
    00365           if (__tlen == __tmultiple * (__to_end - __to))
    00366         __ret = codecvt_base::noconv;
    00367           else if (__tlen == 0)
    00368         __ret = codecvt_base::ok;
    00369           else
    00370         __ret = codecvt_base::partial;
    00371         }
    00372       else
    00373         __ret = codecvt_base::error;
    00374     }
    00375       return __ret;
    00376     }
    00377
    00378   template<typename _InternT, typename _ExternT>
    00379     codecvt_base::result
    00380     codecvt<_InternT, _ExternT, __enc_traits>::
    00381     do_in(state_type& __state, const extern_type* __from,
    00382       const extern_type* __from_end, const extern_type*& __from_next,
    00383       intern_type* __to, intern_type* __to_end,
    00384       intern_type*& __to_next) const
    00385     {
    00386       result __ret = codecvt_base::error;
    00387       if (__state._M_good())
    00388     {
    00389       typedef state_type::__desc_type   __desc_type;
    00390       const __desc_type* __desc = __state._M_get_in_descriptor();
    00391       const size_t __fmultiple = sizeof(extern_type);
    00392       size_t __flen = __fmultiple * (__from_end - __from);
    00393       const size_t __tmultiple = sizeof(intern_type);
    00394       size_t __tlen = __tmultiple * (__to_end - __to);
    00395
    00396       // Argument list for iconv specifies a byte sequence. Thus,
    00397       // all to/from arrays must be brutally casted to char*.
    00398       char* __cto = reinterpret_cast<char*>(__to);
    00399       char* __cfrom;
    00400       size_t __conv;
    00401
    00402       // Some encodings need a byte order marker as the first item
    00403       // in the byte stream, to designate endian-ness. The default
    00404       // value for the byte order marker is NULL, so if this is
    00405       // the case, it's not necessary and we can just go on our
    00406       // merry way.
    00407       int __ext_bom = __state._M_get_external_bom();
    00408       if (__ext_bom)
    00409         {
    00410           size_t __size = __from_end - __from;
    00411           extern_type* __cfixed =  static_cast<extern_type*>(__builtin_alloca(sizeof(extern_type) * (__size + 1)));
    00412           __cfixed[0] = static_cast<extern_type>(__ext_bom);
    00413           char_traits<extern_type>::copy(__cfixed + 1, __from, __size);
    00414           __cfrom = reinterpret_cast<char*>(__cfixed);
    00415           __conv = __iconv_adaptor(iconv, *__desc, &__cfrom,
    00416                                        &__flen, &__cto, &__tlen);
    00417         }
    00418       else
    00419         {
    00420           extern_type* __cfixed = const_cast<extern_type*>(__from);
    00421           __cfrom = reinterpret_cast<char*>(__cfixed);
    00422           __conv = __iconv_adaptor(iconv, *__desc, &__cfrom,
    00423                                        &__flen, &__cto, &__tlen);
    00424         }
    00425
    00426
    00427       if (__conv != size_t(-1))
    00428         {
    00429           __from_next = reinterpret_cast<const extern_type*>(__cfrom);
    00430           __to_next = reinterpret_cast<intern_type*>(__cto);
    00431           __ret = codecvt_base::ok;
    00432         }
    00433       else
    00434         {
    00435           if (__flen < static_cast<size_t>(__from_end - __from))
    00436         {
    00437           __from_next = reinterpret_cast<const extern_type*>(__cfrom);
    00438           __to_next = reinterpret_cast<intern_type*>(__cto);
    00439           __ret = codecvt_base::partial;
    00440         }
    00441           else
    00442         __ret = codecvt_base::error;
    00443         }
    00444     }
    00445       return __ret;
    00446     }
    00447
    00448   template<typename _InternT, typename _ExternT>
    00449     int
    00450     codecvt<_InternT, _ExternT, __enc_traits>::
    00451     do_encoding() const throw()
    00452     {
    00453       int __ret = 0;
    00454       if (sizeof(_ExternT) <= sizeof(_InternT))
    00455     __ret = sizeof(_InternT)/sizeof(_ExternT);
    00456       return __ret;
    00457     }
    00458
    00459   template<typename _InternT, typename _ExternT>
    00460     bool
    00461     codecvt<_InternT, _ExternT, __enc_traits>::
    00462     do_always_noconv() const throw()
    00463     { return false; }
    00464
    00465   template<typename _InternT, typename _ExternT>
    00466     int
    00467     codecvt<_InternT, _ExternT, __enc_traits>::
    00468     do_length(state_type&, const extern_type* __from,
    00469           const extern_type* __end, size_t __max) const
    00470     { return std::min(__max, static_cast<size_t>(__end - __from)); }
    00471
    00472   // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00473   // 74.  Garbled text for codecvt::do_max_length
    00474   template<typename _InternT, typename _ExternT>
    00475     int
    00476     codecvt<_InternT, _ExternT, __enc_traits>::
    00477     do_max_length() const throw()
    00478     { return 1; }
    00479