codecvt_specializations.h

00001 // Locale support (codecvt) -*- C++ -*-
00002 
00003 // Copyright (C) 2000, 2001, 2002 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 to codecvt.cc can have _S_max_size definition.
00040 #define _GLIBCPP_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(0), _M_int_bom(0)
00085     {
00086       strncpy(_M_int_enc, __int, _S_max_size);
00087       strncpy(_M_ext_enc, __ext, _S_max_size);
00088     }
00089 
00090     // 21.1.2 traits typedefs
00091     // p4
00092     // typedef STATE_T state_type
00093     // requires: state_type shall meet the requirements of
00094     // CopyConstructible types (20.1.3)
00095     __enc_traits(const __enc_traits& __obj): _M_in_desc(0), _M_out_desc(0)
00096     {
00097       strncpy(_M_int_enc, __obj._M_int_enc, _S_max_size);
00098       strncpy(_M_ext_enc, __obj._M_ext_enc, _S_max_size);
00099       _M_ext_bom = __obj._M_ext_bom;
00100       _M_int_bom = __obj._M_int_bom;
00101     }
00102 
00103     // Need assignment operator as well.
00104     __enc_traits&
00105     operator=(const __enc_traits& __obj)
00106     {
00107       strncpy(_M_int_enc, __obj._M_int_enc, _S_max_size);
00108       strncpy(_M_ext_enc, __obj._M_ext_enc, _S_max_size);
00109       _M_in_desc = 0;
00110       _M_out_desc = 0;
00111       _M_ext_bom = __obj._M_ext_bom;
00112       _M_int_bom = __obj._M_int_bom;
00113       return *this;
00114     }
00115 
00116     ~__enc_traits()
00117     {
00118       __desc_type __err = reinterpret_cast<iconv_t>(-1);
00119       if (_M_in_desc && _M_in_desc != __err) 
00120     iconv_close(_M_in_desc);
00121       if (_M_out_desc && _M_out_desc != __err) 
00122     iconv_close(_M_out_desc);
00123     } 
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("creating iconv input descriptor failed.");
00134     }
00135       if (!_M_out_desc)
00136     {
00137       _M_out_desc = iconv_open(_M_ext_enc, _M_int_enc);
00138       if (_M_out_desc == __err)
00139         __throw_runtime_error("creating iconv output descriptor failed.");
00140     }
00141     }
00142 
00143     bool
00144     _M_good()
00145     { 
00146       const __desc_type __err = reinterpret_cast<iconv_t>(-1);
00147       bool __test = _M_in_desc && _M_in_desc != __err; 
00148       __test &=  _M_out_desc && _M_out_desc != __err;
00149       return __test;
00150     }
00151 
00152     const __desc_type* 
00153     _M_get_in_descriptor()
00154     { return &_M_in_desc; }
00155 
00156     const __desc_type* 
00157     _M_get_out_descriptor()
00158     { return &_M_out_desc; }
00159 
00160     int 
00161     _M_get_external_bom()
00162     { return _M_ext_bom; }
00163 
00164     int 
00165     _M_get_internal_bom()
00166     { return _M_int_bom; }
00167 
00168     const char* 
00169     _M_get_internal_enc()
00170     { return _M_int_enc; }
00171 
00172     const char* 
00173     _M_get_external_enc()
00174     { return _M_ext_enc; }
00175   };
00176 
00177   // Partial specialization
00178   // This specialization takes advantage of iconv to provide code
00179   // conversions between a large number of character encodings.
00180   template<typename _InternT, typename _ExternT>
00181     class codecvt<_InternT, _ExternT, __enc_traits>
00182     : public __codecvt_abstract_base<_InternT, _ExternT, __enc_traits>
00183     {
00184     public:      
00185       // Types:
00186       typedef codecvt_base::result          result;
00187       typedef _InternT                  intern_type;
00188       typedef _ExternT                  extern_type;
00189       typedef __enc_traits              state_type;
00190       typedef __enc_traits::__desc_type         __desc_type;
00191       typedef __enc_traits              __enc_type;
00192 
00193       // Data Members:
00194       static locale::id         id;
00195 
00196       explicit 
00197       codecvt(size_t __refs = 0)
00198       : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
00199       { }
00200 
00201       explicit 
00202       codecvt(__enc_type* __enc, size_t __refs = 0)
00203       : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
00204       { }
00205 
00206     protected:
00207       virtual 
00208       ~codecvt() { }
00209 
00210       virtual result
00211       do_out(state_type& __state, const intern_type* __from, 
00212          const intern_type* __from_end, const intern_type*& __from_next,
00213          extern_type* __to, extern_type* __to_end,
00214          extern_type*& __to_next) const;
00215 
00216       virtual result
00217       do_unshift(state_type& __state, extern_type* __to, 
00218          extern_type* __to_end, extern_type*& __to_next) const;
00219 
00220       virtual result
00221       do_in(state_type& __state, const extern_type* __from, 
00222         const extern_type* __from_end, const extern_type*& __from_next,
00223         intern_type* __to, intern_type* __to_end, 
00224         intern_type*& __to_next) const;
00225 
00226       virtual int 
00227       do_encoding() const throw();
00228 
00229       virtual bool 
00230       do_always_noconv() const throw();
00231 
00232       virtual int 
00233       do_length(const state_type&, const extern_type* __from, 
00234         const extern_type* __end, size_t __max) const;
00235 
00236       virtual int 
00237       do_max_length() const throw();
00238     };
00239 
00240   template<typename _InternT, typename _ExternT>
00241     locale::id 
00242     codecvt<_InternT, _ExternT, __enc_traits>::id;
00243 
00244   // This adaptor works around the signature problems of the second
00245   // argument to iconv():  SUSv2 and others use 'const char**', but glibc 2.2
00246   // uses 'char**', which matches the POSIX 1003.1-2001 standard.
00247   // Using this adaptor, g++ will do the work for us.
00248   template<typename _T>
00249     inline size_t
00250     __iconv_adaptor(size_t(*__func)(iconv_t, _T, size_t*, char**, size_t*),
00251                     iconv_t __cd, char** __inbuf, size_t* __inbytes,
00252                     char** __outbuf, size_t* __outbytes)
00253     { return __func(__cd, (_T)__inbuf, __inbytes, __outbuf, __outbytes); }
00254 
00255   template<typename _InternT, typename _ExternT>
00256     codecvt_base::result
00257     codecvt<_InternT, _ExternT, __enc_traits>::
00258     do_out(state_type& __state, const intern_type* __from, 
00259        const intern_type* __from_end, const intern_type*& __from_next,
00260        extern_type* __to, extern_type* __to_end,
00261        extern_type*& __to_next) const
00262     {
00263       result __ret = codecvt_base::error;
00264       if (__state._M_good())
00265     {
00266       typedef state_type::__desc_type   __desc_type;
00267       const __desc_type* __desc = __state._M_get_out_descriptor();
00268       const size_t __fmultiple = sizeof(intern_type);
00269       size_t __fbytes = __fmultiple * (__from_end - __from);
00270       const size_t __tmultiple = sizeof(extern_type);
00271       size_t __tbytes = __tmultiple * (__to_end - __to); 
00272       
00273       // Argument list for iconv specifies a byte sequence. Thus,
00274       // all to/from arrays must be brutally casted to char*.
00275       char* __cto = reinterpret_cast<char*>(__to);
00276       char* __cfrom;
00277       size_t __conv;
00278 
00279       // Some encodings need a byte order marker as the first item
00280       // in the byte stream, to designate endian-ness. The default
00281       // value for the byte order marker is NULL, so if this is
00282       // the case, it's not necessary and we can just go on our
00283       // merry way.
00284       int __int_bom = __state._M_get_internal_bom();
00285       if (__int_bom)
00286         {     
00287           size_t __size = __from_end - __from;
00288           intern_type* __cfixed = static_cast<intern_type*>(__builtin_alloca(sizeof(intern_type) * (__size + 1)));
00289           __cfixed[0] = static_cast<intern_type>(__int_bom);
00290           char_traits<intern_type>::copy(__cfixed + 1, __from, __size);
00291           __cfrom = reinterpret_cast<char*>(__cfixed);
00292           __conv = __iconv_adaptor(iconv, *__desc, &__cfrom,
00293                                         &__fbytes, &__cto, &__tbytes); 
00294         }
00295       else
00296         {
00297           intern_type* __cfixed = const_cast<intern_type*>(__from);
00298           __cfrom = reinterpret_cast<char*>(__cfixed);
00299           __conv = __iconv_adaptor(iconv, *__desc, &__cfrom, &__fbytes, 
00300                        &__cto, &__tbytes); 
00301         }
00302 
00303       if (__conv != size_t(-1))
00304         {
00305           __from_next = reinterpret_cast<const intern_type*>(__cfrom);
00306           __to_next = reinterpret_cast<extern_type*>(__cto);
00307           __ret = codecvt_base::ok;
00308         }
00309       else 
00310         {
00311           if (__fbytes < __fmultiple * (__from_end - __from))
00312         {
00313           __from_next = reinterpret_cast<const intern_type*>(__cfrom);
00314           __to_next = reinterpret_cast<extern_type*>(__cto);
00315           __ret = codecvt_base::partial;
00316         }
00317           else
00318         __ret = codecvt_base::error;
00319         }
00320     }
00321       return __ret; 
00322     }
00323 
00324   template<typename _InternT, typename _ExternT>
00325     codecvt_base::result
00326     codecvt<_InternT, _ExternT, __enc_traits>::
00327     do_unshift(state_type& __state, extern_type* __to, 
00328            extern_type* __to_end, extern_type*& __to_next) const
00329     {
00330       result __ret = codecvt_base::error;
00331       if (__state._M_good())
00332     {
00333       typedef state_type::__desc_type   __desc_type;
00334       const __desc_type* __desc = __state._M_get_in_descriptor();
00335       const size_t __tmultiple = sizeof(intern_type);
00336       size_t __tlen = __tmultiple * (__to_end - __to); 
00337       
00338       // Argument list for iconv specifies a byte sequence. Thus,
00339       // all to/from arrays must be brutally casted to char*.
00340       char* __cto = reinterpret_cast<char*>(__to);
00341       size_t __conv = __iconv_adaptor(iconv,*__desc, NULL, NULL,
00342                                           &__cto, &__tlen); 
00343       
00344       if (__conv != size_t(-1))
00345         {
00346           __to_next = reinterpret_cast<extern_type*>(__cto);
00347           if (__tlen == __tmultiple * (__to_end - __to))
00348         __ret = codecvt_base::noconv;
00349           else if (__tlen == 0)
00350         __ret = codecvt_base::ok;
00351           else
00352         __ret = codecvt_base::partial;
00353         }
00354       else 
00355         __ret = codecvt_base::error;
00356     }
00357       return __ret; 
00358     }
00359    
00360   template<typename _InternT, typename _ExternT>
00361     codecvt_base::result
00362     codecvt<_InternT, _ExternT, __enc_traits>::
00363     do_in(state_type& __state, const extern_type* __from, 
00364       const extern_type* __from_end, const extern_type*& __from_next,
00365       intern_type* __to, intern_type* __to_end, 
00366       intern_type*& __to_next) const
00367     { 
00368       result __ret = codecvt_base::error;
00369       if (__state._M_good())
00370     {
00371       typedef state_type::__desc_type   __desc_type;
00372       const __desc_type* __desc = __state._M_get_in_descriptor();
00373       const size_t __fmultiple = sizeof(extern_type);
00374       size_t __flen = __fmultiple * (__from_end - __from);
00375       const size_t __tmultiple = sizeof(intern_type);
00376       size_t __tlen = __tmultiple * (__to_end - __to); 
00377       
00378       // Argument list for iconv specifies a byte sequence. Thus,
00379       // all to/from arrays must be brutally casted to char*.
00380       char* __cto = reinterpret_cast<char*>(__to);
00381       char* __cfrom;
00382       size_t __conv;
00383 
00384       // Some encodings need a byte order marker as the first item
00385       // in the byte stream, to designate endian-ness. The default
00386       // value for the byte order marker is NULL, so if this is
00387       // the case, it's not necessary and we can just go on our
00388       // merry way.
00389       int __ext_bom = __state._M_get_external_bom();
00390       if (__ext_bom)
00391         {     
00392           size_t __size = __from_end - __from;
00393           extern_type* __cfixed =  static_cast<extern_type*>(__builtin_alloca(sizeof(extern_type) * (__size + 1)));
00394           __cfixed[0] = static_cast<extern_type>(__ext_bom);
00395           char_traits<extern_type>::copy(__cfixed + 1, __from, __size);
00396           __cfrom = reinterpret_cast<char*>(__cfixed);
00397           __conv = __iconv_adaptor(iconv, *__desc, &__cfrom,
00398                                        &__flen, &__cto, &__tlen); 
00399         }
00400       else
00401         {
00402           extern_type* __cfixed = const_cast<extern_type*>(__from);
00403           __cfrom = reinterpret_cast<char*>(__cfixed);
00404           __conv = __iconv_adaptor(iconv, *__desc, &__cfrom,
00405                                        &__flen, &__cto, &__tlen); 
00406         }
00407 
00408       
00409       if (__conv != size_t(-1))
00410         {
00411           __from_next = reinterpret_cast<const extern_type*>(__cfrom);
00412           __to_next = reinterpret_cast<intern_type*>(__cto);
00413           __ret = codecvt_base::ok;
00414         }
00415       else 
00416         {
00417           if (__flen < static_cast<size_t>(__from_end - __from))
00418         {
00419           __from_next = reinterpret_cast<const extern_type*>(__cfrom);
00420           __to_next = reinterpret_cast<intern_type*>(__cto);
00421           __ret = codecvt_base::partial;
00422         }
00423           else
00424         __ret = codecvt_base::error;
00425         }
00426     }
00427       return __ret; 
00428     }
00429   
00430   template<typename _InternT, typename _ExternT>
00431     int 
00432     codecvt<_InternT, _ExternT, __enc_traits>::
00433     do_encoding() const throw()
00434     {
00435       int __ret = 0;
00436       if (sizeof(_ExternT) <= sizeof(_InternT))
00437     __ret = sizeof(_InternT)/sizeof(_ExternT);
00438       return __ret; 
00439     }
00440   
00441   template<typename _InternT, typename _ExternT>
00442     bool 
00443     codecvt<_InternT, _ExternT, __enc_traits>::
00444     do_always_noconv() const throw()
00445     { return false; }
00446   
00447   template<typename _InternT, typename _ExternT>
00448     int 
00449     codecvt<_InternT, _ExternT, __enc_traits>::
00450     do_length(const state_type&, const extern_type* __from, 
00451           const extern_type* __end, size_t __max) const
00452     { return min(__max, static_cast<size_t>(__end - __from)); }
00453 
00454 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
00455 // 74.  Garbled text for codecvt::do_max_length
00456   template<typename _InternT, typename _ExternT>
00457     int 
00458     codecvt<_InternT, _ExternT, __enc_traits>::
00459     do_max_length() const throw()
00460     { return 1; }
00461 #endif

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