# codecvt_specializations.h

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    00001 // Locale support (codecvt) -*- C++ -*-
    00002
    00003 // Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
    00004 //  Free Software Foundation, Inc.
    00005 //
    00006 // This file is part of the GNU ISO C++ Library.  This library is free
    00007 // software; you can redistribute it and/or modify it under the
    00008 // terms of the GNU General Public License as published by the
    00009 // Free Software Foundation; either version 2, or (at your option)
    00010 // any later version.
    00011
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00015 // GNU General Public License for more details.
    00016
    00017 // You should have received a copy of the GNU General Public License along
    00018 // with this library; see the file COPYING.  If not, write to the Free
    00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    00020 // USA.
    00021
    00022 // As a special exception, you may use this file as part of a free software
    00023 // library without restriction.  Specifically, if other files instantiate
    00024 // templates or use macros or inline functions from this file, or you compile
    00025 // this file and link it with other files to produce an executable, this
    00026 // file does not by itself cause the resulting executable to be covered by
    00027 // the GNU General Public License.  This exception does not however
    00028 // invalidate any other reasons why the executable file might be covered by
    00029 // the GNU General Public License.
    00030
    00031 //
    00032 // ISO C++ 14882: 22.2.1.5 Template class codecvt
    00033 //
    00034
    00035 // Written by Benjamin Kosnik <bkoz@redhat.com>
    00036
    00037 /** @file ext/codecvt_specializations.h
    00038  *  This file is a GNU extension to the Standard C++ Library.
    00039  */
    00040
    00041 #ifndef _EXT_CODECVT_SPECIALIZATIONS_H
    00042 #define _EXT_CODECVT_SPECIALIZATIONS_H 1
    00043
    00044 #include <bits/c++config.h>
    00045 #include <locale>
    00046 #include <iconv.h>
    00047
    00048 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
    00049
    00050   /// Extension to use iconv for dealing with character encodings.
    00051   // This includes conversions and comparisons between various character
    00052   // sets.  This object encapsulates data that may need to be shared between
    00053   // char_traits, codecvt and ctype.
    00054   class encoding_state
    00055   {
    00056   public:
    00057     // Types:
    00058     // NB: A conversion descriptor subsumes and enhances the
    00059     // functionality of a simple state type such as mbstate_t.
    00060     typedef iconv_t descriptor_type;
    00061
    00062   protected:
    00063     // Name of internal character set encoding.
    00064     std::string         _M_int_enc;
    00065
    00066     // Name of external character set encoding.
    00067     std::string     _M_ext_enc;
    00068
    00069     // Conversion descriptor between external encoding to internal encoding.
    00070     descriptor_type _M_in_desc;
    00071
    00072     // Conversion descriptor between internal encoding to external encoding.
    00073     descriptor_type _M_out_desc;
    00074
    00075     // The byte-order marker for the external encoding, if necessary.
    00076     int         _M_ext_bom;
    00077
    00078     // The byte-order marker for the internal encoding, if necessary.
    00079     int         _M_int_bom;
    00080
    00081     // Number of external bytes needed to construct one complete
    00082     // character in the internal encoding.
    00083     // NB: -1 indicates variable, or stateful, encodings.
    00084     int         _M_bytes;
    00085
    00086   public:
    00087     explicit
    00088     encoding_state()
    00089     : _M_in_desc(0), _M_out_desc(0), _M_ext_bom(0), _M_int_bom(0), _M_bytes(0)
    00090     { }
    00091
    00092     explicit
    00093     encoding_state(const char* __int, const char* __ext,
    00094            int __ibom = 0, int __ebom = 0, int __bytes = 1)
    00095     : _M_int_enc(__int), _M_ext_enc(__ext), _M_in_desc(0), _M_out_desc(0),
    00096       _M_ext_bom(__ebom), _M_int_bom(__ibom), _M_bytes(__bytes)
    00097     { init(); }
    00098
    00099     // 21.1.2 traits typedefs
    00100     // p4
    00101     // typedef STATE_T state_type
    00102     // requires: state_type shall meet the requirements of
    00103     // CopyConstructible types (20.1.3)
    00104     // NB: This does not preserve the actual state of the conversion
    00105     // descriptor member, but it does duplicate the encoding
    00106     // information.
    00107     encoding_state(const encoding_state& __obj) : _M_in_desc(0), _M_out_desc(0)
    00108     { construct(__obj); }
    00109
    00110     // Need assignment operator as well.
    00111     encoding_state&
    00112     operator=(const encoding_state& __obj)
    00113     {
    00114       construct(__obj);
    00115       return *this;
    00116     }
    00117
    00118     ~encoding_state()
    00119     { destroy(); }
    00120
    00121     bool
    00122     good() const throw()
    00123     {
    00124       const descriptor_type __err = (iconv_t)(-1);
    00125       bool __test = _M_in_desc && _M_in_desc != __err;
    00126       __test &=  _M_out_desc && _M_out_desc != __err;
    00127       return __test;
    00128     }
    00129
    00130     int
    00131     character_ratio() const
    00132     { return _M_bytes; }
    00133
    00134     const std::string
    00135     internal_encoding() const
    00136     { return _M_int_enc; }
    00137
    00138     int
    00139     internal_bom() const
    00140     { return _M_int_bom; }
    00141
    00142     const std::string
    00143     external_encoding() const
    00144     { return _M_ext_enc; }
    00145
    00146     int
    00147     external_bom() const
    00148     { return _M_ext_bom; }
    00149
    00150     const descriptor_type&
    00151     in_descriptor() const
    00152     { return _M_in_desc; }
    00153
    00154     const descriptor_type&
    00155     out_descriptor() const
    00156     { return _M_out_desc; }
    00157
    00158   protected:
    00159     void
    00160     init()
    00161     {
    00162       const descriptor_type __err = (iconv_t)(-1);
    00163       const bool __have_encodings = _M_int_enc.size() && _M_ext_enc.size();
    00164       if (!_M_in_desc && __have_encodings)
    00165     {
    00166       _M_in_desc = iconv_open(_M_int_enc.c_str(), _M_ext_enc.c_str());
    00167       if (_M_in_desc == __err)
    00168         std::__throw_runtime_error(__N("encoding_state::_M_init "
    00169                     "creating iconv input descriptor failed"));
    00170     }
    00171       if (!_M_out_desc && __have_encodings)
    00172     {
    00173       _M_out_desc = iconv_open(_M_ext_enc.c_str(), _M_int_enc.c_str());
    00174       if (_M_out_desc == __err)
    00175         std::__throw_runtime_error(__N("encoding_state::_M_init "
    00176                   "creating iconv output descriptor failed"));
    00177     }
    00178     }
    00179
    00180     void
    00181     construct(const encoding_state& __obj)
    00182     {
    00183       destroy();
    00184       _M_int_enc = __obj._M_int_enc;
    00185       _M_ext_enc = __obj._M_ext_enc;
    00186       _M_ext_bom = __obj._M_ext_bom;
    00187       _M_int_bom = __obj._M_int_bom;
    00188       _M_bytes = __obj._M_bytes;
    00189       init();
    00190     }
    00191
    00192     void
    00193     destroy() throw()
    00194     {
    00195       const descriptor_type __err = (iconv_t)(-1);
    00196       if (_M_in_desc && _M_in_desc != __err)
    00197     {
    00198       iconv_close(_M_in_desc);
    00199       _M_in_desc = 0;
    00200     }
    00201       if (_M_out_desc && _M_out_desc != __err)
    00202     {
    00203       iconv_close(_M_out_desc);
    00204       _M_out_desc = 0;
    00205     }
    00206     }
    00207   };
    00208
    00209   /// encoding_char_traits
    00210   // Custom traits type with encoding_state for the state type, and the
    00211   // associated fpos<encoding_state> for the position type, all other
    00212   // bits equivalent to the required char_traits instantiations.
    00213   template<typename _CharT>
    00214     struct encoding_char_traits : public std::char_traits<_CharT>
    00215     {
    00216       typedef encoding_state                state_type;
    00217       typedef typename std::fpos<state_type>        pos_type;
    00218     };
    00219
    00220 _GLIBCXX_END_NAMESPACE
    00221
    00222
    00223 _GLIBCXX_BEGIN_NAMESPACE(std)
    00224
    00225   using __gnu_cxx::encoding_state;
    00226
    00227   /// codecvt<InternT, _ExternT, encoding_state> specialization.
    00228   // This partial specialization takes advantage of iconv to provide
    00229   // code conversions between a large number of character encodings.
    00230   template<typename _InternT, typename _ExternT>
    00231     class codecvt<_InternT, _ExternT, encoding_state>
    00232     : public __codecvt_abstract_base<_InternT, _ExternT, encoding_state>
    00233     {
    00234     public:
    00235       // Types:
    00236       typedef codecvt_base::result          result;
    00237       typedef _InternT                  intern_type;
    00238       typedef _ExternT                  extern_type;
    00239       typedef __gnu_cxx::encoding_state         state_type;
    00240       typedef state_type::descriptor_type       descriptor_type;
    00241
    00242       // Data Members:
    00243       static locale::id         id;
    00244
    00245       explicit
    00246       codecvt(size_t __refs = 0)
    00247       : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
    00248       { }
    00249
    00250       explicit
    00251       codecvt(state_type& __enc, size_t __refs = 0)
    00252       : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
    00253       { }
    00254
    00255      protected:
    00256       virtual
    00257       ~codecvt() { }
    00258
    00259       virtual result
    00260       do_out(state_type& __state, const intern_type* __from,
    00261          const intern_type* __from_end, const intern_type*& __from_next,
    00262          extern_type* __to, extern_type* __to_end,
    00263          extern_type*& __to_next) const;
    00264
    00265       virtual result
    00266       do_unshift(state_type& __state, extern_type* __to,
    00267          extern_type* __to_end, extern_type*& __to_next) const;
    00268
    00269       virtual result
    00270       do_in(state_type& __state, const extern_type* __from,
    00271         const extern_type* __from_end, const extern_type*& __from_next,
    00272         intern_type* __to, intern_type* __to_end,
    00273         intern_type*& __to_next) const;
    00274
    00275       virtual int
    00276       do_encoding() const throw();
    00277
    00278       virtual bool
    00279       do_always_noconv() const throw();
    00280
    00281       virtual int
    00282       do_length(state_type&, const extern_type* __from,
    00283         const extern_type* __end, size_t __max) const;
    00284
    00285       virtual int
    00286       do_max_length() const throw();
    00287     };
    00288
    00289   template<typename _InternT, typename _ExternT>
    00290     locale::id
    00291     codecvt<_InternT, _ExternT, encoding_state>::id;
    00292
    00293   // This adaptor works around the signature problems of the second
    00294   // argument to iconv():  SUSv2 and others use 'const char**', but glibc 2.2
    00295   // uses 'char**', which matches the POSIX 1003.1-2001 standard.
    00296   // Using this adaptor, g++ will do the work for us.
    00297   template<typename _Tp>
    00298     inline size_t
    00299     __iconv_adaptor(size_t(*__func)(iconv_t, _Tp, size_t*, char**, size_t*),
    00300                     iconv_t __cd, char** __inbuf, size_t* __inbytes,
    00301                     char** __outbuf, size_t* __outbytes)
    00302     { return __func(__cd, (_Tp)__inbuf, __inbytes, __outbuf, __outbytes); }
    00303
    00304   template<typename _InternT, typename _ExternT>
    00305     codecvt_base::result
    00306     codecvt<_InternT, _ExternT, encoding_state>::
    00307     do_out(state_type& __state, const intern_type* __from,
    00308        const intern_type* __from_end, const intern_type*& __from_next,
    00309        extern_type* __to, extern_type* __to_end,
    00310        extern_type*& __to_next) const
    00311     {
    00312       result __ret = codecvt_base::error;
    00313       if (__state.good())
    00314     {
    00315       const descriptor_type& __desc = __state.out_descriptor();
    00316       const size_t __fmultiple = sizeof(intern_type);
    00317       size_t __fbytes = __fmultiple * (__from_end - __from);
    00318       const size_t __tmultiple = sizeof(extern_type);
    00319       size_t __tbytes = __tmultiple * (__to_end - __to);
    00320
    00321       // Argument list for iconv specifies a byte sequence. Thus,
    00322       // all to/from arrays must be brutally casted to char*.
    00323       char* __cto = reinterpret_cast<char*>(__to);
    00324       char* __cfrom;
    00325       size_t __conv;
    00326
    00327       // Some encodings need a byte order marker as the first item
    00328       // in the byte stream, to designate endian-ness. The default
    00329       // value for the byte order marker is NULL, so if this is
    00330       // the case, it's not necessary and we can just go on our
    00331       // merry way.
    00332       int __int_bom = __state.internal_bom();
    00333       if (__int_bom)
    00334         {
    00335           size_t __size = __from_end - __from;
    00336           intern_type* __cfixed = static_cast<intern_type*>
    00337         (__builtin_alloca(sizeof(intern_type) * (__size + 1)));
    00338           __cfixed[0] = static_cast<intern_type>(__int_bom);
    00339           char_traits<intern_type>::copy(__cfixed + 1, __from, __size);
    00340           __cfrom = reinterpret_cast<char*>(__cfixed);
    00341           __conv = __iconv_adaptor(iconv, __desc, &__cfrom,
    00342                                         &__fbytes, &__cto, &__tbytes);
    00343         }
    00344       else
    00345         {
    00346           intern_type* __cfixed = const_cast<intern_type*>(__from);
    00347           __cfrom = reinterpret_cast<char*>(__cfixed);
    00348           __conv = __iconv_adaptor(iconv, __desc, &__cfrom, &__fbytes,
    00349                        &__cto, &__tbytes);
    00350         }
    00351
    00352       if (__conv != size_t(-1))
    00353         {
    00354           __from_next = reinterpret_cast<const intern_type*>(__cfrom);
    00355           __to_next = reinterpret_cast<extern_type*>(__cto);
    00356           __ret = codecvt_base::ok;
    00357         }
    00358       else
    00359         {
    00360           if (__fbytes < __fmultiple * (__from_end - __from))
    00361         {
    00362           __from_next = reinterpret_cast<const intern_type*>(__cfrom);
    00363           __to_next = reinterpret_cast<extern_type*>(__cto);
    00364           __ret = codecvt_base::partial;
    00365         }
    00366           else
    00367         __ret = codecvt_base::error;
    00368         }
    00369     }
    00370       return __ret;
    00371     }
    00372
    00373   template<typename _InternT, typename _ExternT>
    00374     codecvt_base::result
    00375     codecvt<_InternT, _ExternT, encoding_state>::
    00376     do_unshift(state_type& __state, extern_type* __to,
    00377            extern_type* __to_end, extern_type*& __to_next) const
    00378     {
    00379       result __ret = codecvt_base::error;
    00380       if (__state.good())
    00381     {
    00382       const descriptor_type& __desc = __state.in_descriptor();
    00383       const size_t __tmultiple = sizeof(intern_type);
    00384       size_t __tlen = __tmultiple * (__to_end - __to);
    00385
    00386       // Argument list for iconv specifies a byte sequence. Thus,
    00387       // all to/from arrays must be brutally casted to char*.
    00388       char* __cto = reinterpret_cast<char*>(__to);
    00389       size_t __conv = __iconv_adaptor(iconv,__desc, NULL, NULL,
    00390                                           &__cto, &__tlen);
    00391
    00392       if (__conv != size_t(-1))
    00393         {
    00394           __to_next = reinterpret_cast<extern_type*>(__cto);
    00395           if (__tlen == __tmultiple * (__to_end - __to))
    00396         __ret = codecvt_base::noconv;
    00397           else if (__tlen == 0)
    00398         __ret = codecvt_base::ok;
    00399           else
    00400         __ret = codecvt_base::partial;
    00401         }
    00402       else
    00403         __ret = codecvt_base::error;
    00404     }
    00405       return __ret;
    00406     }
    00407
    00408   template<typename _InternT, typename _ExternT>
    00409     codecvt_base::result
    00410     codecvt<_InternT, _ExternT, encoding_state>::
    00411     do_in(state_type& __state, const extern_type* __from,
    00412       const extern_type* __from_end, const extern_type*& __from_next,
    00413       intern_type* __to, intern_type* __to_end,
    00414       intern_type*& __to_next) const
    00415     {
    00416       result __ret = codecvt_base::error;
    00417       if (__state.good())
    00418     {
    00419       const descriptor_type& __desc = __state.in_descriptor();
    00420       const size_t __fmultiple = sizeof(extern_type);
    00421       size_t __flen = __fmultiple * (__from_end - __from);
    00422       const size_t __tmultiple = sizeof(intern_type);
    00423       size_t __tlen = __tmultiple * (__to_end - __to);
    00424
    00425       // Argument list for iconv specifies a byte sequence. Thus,
    00426       // all to/from arrays must be brutally casted to char*.
    00427       char* __cto = reinterpret_cast<char*>(__to);
    00428       char* __cfrom;
    00429       size_t __conv;
    00430
    00431       // Some encodings need a byte order marker as the first item
    00432       // in the byte stream, to designate endian-ness. The default
    00433       // value for the byte order marker is NULL, so if this is
    00434       // the case, it's not necessary and we can just go on our
    00435       // merry way.
    00436       int __ext_bom = __state.external_bom();
    00437       if (__ext_bom)
    00438         {
    00439           size_t __size = __from_end - __from;
    00440           extern_type* __cfixed =  static_cast<extern_type*>
    00441         (__builtin_alloca(sizeof(extern_type) * (__size + 1)));
    00442           __cfixed[0] = static_cast<extern_type>(__ext_bom);
    00443           char_traits<extern_type>::copy(__cfixed + 1, __from, __size);
    00444           __cfrom = reinterpret_cast<char*>(__cfixed);
    00445           __conv = __iconv_adaptor(iconv, __desc, &__cfrom,
    00446                                        &__flen, &__cto, &__tlen);
    00447         }
    00448       else
    00449         {
    00450           extern_type* __cfixed = const_cast<extern_type*>(__from);
    00451           __cfrom = reinterpret_cast<char*>(__cfixed);
    00452           __conv = __iconv_adaptor(iconv, __desc, &__cfrom,
    00453                                        &__flen, &__cto, &__tlen);
    00454         }
    00455
    00456
    00457       if (__conv != size_t(-1))
    00458         {
    00459           __from_next = reinterpret_cast<const extern_type*>(__cfrom);
    00460           __to_next = reinterpret_cast<intern_type*>(__cto);
    00461           __ret = codecvt_base::ok;
    00462         }
    00463       else
    00464         {
    00465           if (__flen < static_cast<size_t>(__from_end - __from))
    00466         {
    00467           __from_next = reinterpret_cast<const extern_type*>(__cfrom);
    00468           __to_next = reinterpret_cast<intern_type*>(__cto);
    00469           __ret = codecvt_base::partial;
    00470         }
    00471           else
    00472         __ret = codecvt_base::error;
    00473         }
    00474     }
    00475       return __ret;
    00476     }
    00477
    00478   template<typename _InternT, typename _ExternT>
    00479     int
    00480     codecvt<_InternT, _ExternT, encoding_state>::
    00481     do_encoding() const throw()
    00482     {
    00483       int __ret = 0;
    00484       if (sizeof(_ExternT) <= sizeof(_InternT))
    00485     __ret = sizeof(_InternT) / sizeof(_ExternT);
    00486       return __ret;
    00487     }
    00488
    00489   template<typename _InternT, typename _ExternT>
    00490     bool
    00491     codecvt<_InternT, _ExternT, encoding_state>::
    00492     do_always_noconv() const throw()
    00493     { return false; }
    00494
    00495   template<typename _InternT, typename _ExternT>
    00496     int
    00497     codecvt<_InternT, _ExternT, encoding_state>::
    00498     do_length(state_type&, const extern_type* __from,
    00499           const extern_type* __end, size_t __max) const
    00500     { return std::min(__max, static_cast<size_t>(__end - __from)); }
    00501
    00502   // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00503   // 74.  Garbled text for codecvt::do_max_length
    00504   template<typename _InternT, typename _ExternT>
    00505     int
    00506     codecvt<_InternT, _ExternT, encoding_state>::
    00507     do_max_length() const throw()
    00508     { return 1; }
    00509
    00510 _GLIBCXX_END_NAMESPACE
    00511
    00512 #endif