# 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 = 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 = 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 = partial;
    00316         }
    00317           else
    00318         __ret = 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 = 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 = noconv;
    00349           else if (__tlen == 0)
    00350         __ret = ok;
    00351           else
    00352         __ret = partial;
    00353         }
    00354       else
    00355         __ret = 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 = 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 = 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 = partial;
    00422         }
    00423           else
    00424         __ret = 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