libstdc++-v3/include/ext/codecvt_specializations.h

   1 // Locale support (codecvt) -*- C++ -*-
   2
   3 // Copyright (C) 2000-2018 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 //
  26 // ISO C++ 14882: 22.2.1.5 Template class codecvt
  27 //
  28
  29 // Written by Benjamin Kosnik <bkoz@redhat.com>
  30
  31 /** @file ext/codecvt_specializations.h
  32  *  This file is a GNU extension to the Standard C++ Library.
  33  */
  34
  35 #ifndef _EXT_CODECVT_SPECIALIZATIONS_H
  36 #define _EXT_CODECVT_SPECIALIZATIONS_H 1
  37
  38 #include <bits/c++config.h>
  39 #include <locale>
  40 #include <iconv.h>
  41
  42 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
  43 {
  44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  45 _GLIBCXX_BEGIN_NAMESPACE_CXX11
  46
  47   /// Extension to use iconv for dealing with character encodings.
  48   // This includes conversions and comparisons between various character
  49   // sets.  This object encapsulates data that may need to be shared between
  50   // char_traits, codecvt and ctype.
  51   class encoding_state
  52   {
  53   public:
  54     // Types:
  55     // NB: A conversion descriptor subsumes and enhances the
  56     // functionality of a simple state type such as mbstate_t.
  57     typedef iconv_t     descriptor_type;
  58
  59   protected:
  60     // Name of internal character set encoding.
  61     std::string         _M_int_enc;
  62
  63     // Name of external character set encoding.
  64     std::string         _M_ext_enc;
  65
  66     // Conversion descriptor between external encoding to internal encoding.
  67     descriptor_type     _M_in_desc;
  68
  69     // Conversion descriptor between internal encoding to external encoding.
  70     descriptor_type     _M_out_desc;
  71
  72     // The byte-order marker for the external encoding, if necessary.
  73     int                 _M_ext_bom;
  74
  75     // The byte-order marker for the internal encoding, if necessary.
  76     int                 _M_int_bom;
  77
  78     // Number of external bytes needed to construct one complete
  79     // character in the internal encoding.
  80     // NB: -1 indicates variable, or stateful, encodings.
  81     int                 _M_bytes;
  82
  83   public:
  84     explicit
  85     encoding_state()
  86     : _M_in_desc(0), _M_out_desc(0), _M_ext_bom(0), _M_int_bom(0), _M_bytes(0)
  87     { }
  88
  89     explicit
  90     encoding_state(const char* __int, const char* __ext,
  91                    int __ibom = 0, int __ebom = 0, int __bytes = 1)
  92     : _M_int_enc(__int), _M_ext_enc(__ext), _M_in_desc(0), _M_out_desc(0),
  93       _M_ext_bom(__ebom), _M_int_bom(__ibom), _M_bytes(__bytes)
  94     { init(); }
  95
  96     // 21.1.2 traits typedefs
  97     // p4
  98     // typedef STATE_T state_type
  99     // requires: state_type shall meet the requirements of
 100     // CopyConstructible types (20.1.3)
 101     // NB: This does not preserve the actual state of the conversion
 102     // descriptor member, but it does duplicate the encoding
 103     // information.
 104     encoding_state(const encoding_state& __obj) : _M_in_desc(0), _M_out_desc(0)
 105     { construct(__obj); }
 106
 107     // Need assignment operator as well.
 108     encoding_state&
 109     operator=(const encoding_state& __obj)
 110     {
 111       construct(__obj);
 112       return *this;
 113     }
 114
 115     ~encoding_state()
 116     { destroy(); }
 117
 118     bool
 119     good() const throw()
 120     {
 121       const descriptor_type __err = (iconv_t)(-1);
 122       bool __test = _M_in_desc && _M_in_desc != __err;
 123       __test &=  _M_out_desc && _M_out_desc != __err;
 124       return __test;
 125     }
 126
 127     int
 128     character_ratio() const
 129     { return _M_bytes; }
 130
 131     const std::string
 132     internal_encoding() const
 133     { return _M_int_enc; }
 134
 135     int
 136     internal_bom() const
 137     { return _M_int_bom; }
 138
 139     const std::string
 140     external_encoding() const
 141     { return _M_ext_enc; }
 142
 143     int
 144     external_bom() const
 145     { return _M_ext_bom; }
 146
 147     const descriptor_type&
 148     in_descriptor() const
 149     { return _M_in_desc; }
 150
 151     const descriptor_type&
 152     out_descriptor() const
 153     { return _M_out_desc; }
 154
 155   protected:
 156     void
 157     init()
 158     {
 159       const descriptor_type __err = (iconv_t)(-1);
 160       const bool __have_encodings = _M_int_enc.size() && _M_ext_enc.size();
 161       if (!_M_in_desc && __have_encodings)
 162         {
 163           _M_in_desc = iconv_open(_M_int_enc.c_str(), _M_ext_enc.c_str());
 164           if (_M_in_desc == __err)
 165             std::__throw_runtime_error(__N("encoding_state::_M_init "
 166                                     "creating iconv input descriptor failed"));
 167         }
 168       if (!_M_out_desc && __have_encodings)
 169         {
 170           _M_out_desc = iconv_open(_M_ext_enc.c_str(), _M_int_enc.c_str());
 171           if (_M_out_desc == __err)
 172             std::__throw_runtime_error(__N("encoding_state::_M_init "
 173                                   "creating iconv output descriptor failed"));
 174         }
 175     }
 176
 177     void
 178     construct(const encoding_state& __obj)
 179     {
 180       destroy();
 181       _M_int_enc = __obj._M_int_enc;
 182       _M_ext_enc = __obj._M_ext_enc;
 183       _M_ext_bom = __obj._M_ext_bom;
 184       _M_int_bom = __obj._M_int_bom;
 185       _M_bytes = __obj._M_bytes;
 186       init();
 187     }
 188
 189     void
 190     destroy() throw()
 191     {
 192       const descriptor_type __err = (iconv_t)(-1);
 193       if (_M_in_desc && _M_in_desc != __err)
 194         {
 195           iconv_close(_M_in_desc);
 196           _M_in_desc = 0;
 197         }
 198       if (_M_out_desc && _M_out_desc != __err)
 199         {
 200           iconv_close(_M_out_desc);
 201           _M_out_desc = 0;
 202         }
 203     }
 204   };
 205
 206   /// encoding_char_traits
 207   // Custom traits type with encoding_state for the state type, and the
 208   // associated fpos<encoding_state> for the position type, all other
 209   // bits equivalent to the required char_traits instantiations.
 210   template<typename _CharT>
 211     struct encoding_char_traits
 212     : public std::char_traits<_CharT>
 213     {
 214       typedef encoding_state                            state_type;
 215       typedef typename std::fpos<state_type>            pos_type;
 216     };
 217
 218 _GLIBCXX_END_NAMESPACE_CXX11
 219 _GLIBCXX_END_NAMESPACE_VERSION
 220 } // namespace
 221
 222
 223 namespace std _GLIBCXX_VISIBILITY(default)
 224 {
 225 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 226
 227   using __gnu_cxx::encoding_state;
 228
 229   /// codecvt<InternT, _ExternT, encoding_state> specialization.
 230   // This partial specialization takes advantage of iconv to provide
 231   // code conversions between a large number of character encodings.
 232   template<typename _InternT, typename _ExternT>
 233     class codecvt<_InternT, _ExternT, encoding_state>
 234     : public __codecvt_abstract_base<_InternT, _ExternT, encoding_state>
 235     {
 236     public:
 237       // Types:
 238       typedef codecvt_base::result                      result;
 239       typedef _InternT                                  intern_type;
 240       typedef _ExternT                                  extern_type;
 241       typedef __gnu_cxx::encoding_state                 state_type;
 242       typedef state_type::descriptor_type               descriptor_type;
 243
 244       // Data Members:
 245       static locale::id                 id;
 246
 247       explicit
 248       codecvt(size_t __refs = 0)
 249       : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
 250       { }
 251
 252       explicit
 253       codecvt(state_type& __enc, size_t __refs = 0)
 254       : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
 255       { }
 256
 257      protected:
 258       virtual
 259       ~codecvt() { }
 260
 261       virtual result
 262       do_out(state_type& __state, const intern_type* __from,
 263              const intern_type* __from_end, const intern_type*& __from_next,
 264              extern_type* __to, extern_type* __to_end,
 265              extern_type*& __to_next) const;
 266
 267       virtual result
 268       do_unshift(state_type& __state, extern_type* __to,
 269                  extern_type* __to_end, extern_type*& __to_next) const;
 270
 271       virtual result
 272       do_in(state_type& __state, const extern_type* __from,
 273             const extern_type* __from_end, const extern_type*& __from_next,
 274             intern_type* __to, intern_type* __to_end,
 275             intern_type*& __to_next) const;
 276
 277       virtual int
 278       do_encoding() const throw();
 279
 280       virtual bool
 281       do_always_noconv() const throw();
 282
 283       virtual int
 284       do_length(state_type&, const extern_type* __from,
 285                 const extern_type* __end, size_t __max) const;
 286
 287       virtual int
 288       do_max_length() const throw();
 289     };
 290
 291   template<typename _InternT, typename _ExternT>
 292     locale::id
 293     codecvt<_InternT, _ExternT, encoding_state>::id;
 294
 295   // This adaptor works around the signature problems of the second
 296   // argument to iconv():  SUSv2 and others use 'const char**', but glibc 2.2
 297   // uses 'char**', which matches the POSIX 1003.1-2001 standard.
 298   // Using this adaptor, g++ will do the work for us.
 299   template<typename _Tp>
 300     inline size_t
 301     __iconv_adaptor(size_t(*__func)(iconv_t, _Tp, size_t*, char**, size_t*),
 302                     iconv_t __cd, char** __inbuf, size_t* __inbytes,
 303                     char** __outbuf, size_t* __outbytes)
 304     { return __func(__cd, (_Tp)__inbuf, __inbytes, __outbuf, __outbytes); }
 305
 306   template<typename _InternT, typename _ExternT>
 307     codecvt_base::result
 308     codecvt<_InternT, _ExternT, encoding_state>::
 309     do_out(state_type& __state, const intern_type* __from,
 310            const intern_type* __from_end, const intern_type*& __from_next,
 311            extern_type* __to, extern_type* __to_end,
 312            extern_type*& __to_next) const
 313     {
 314       result __ret = codecvt_base::error;
 315       if (__state.good())
 316         {
 317           const descriptor_type& __desc = __state.out_descriptor();
 318           const size_t __fmultiple = sizeof(intern_type);
 319           size_t __fbytes = __fmultiple * (__from_end - __from);
 320           const size_t __tmultiple = sizeof(extern_type);
 321           size_t __tbytes = __tmultiple * (__to_end - __to);
 322
 323           // Argument list for iconv specifies a byte sequence. Thus,
 324           // all to/from arrays must be brutally casted to char*.
 325           char* __cto = reinterpret_cast<char*>(__to);
 326           char* __cfrom;
 327           size_t __conv;
 328
 329           // Some encodings need a byte order marker as the first item
 330           // in the byte stream, to designate endian-ness. The default
 331           // value for the byte order marker is NULL, so if this is
 332           // the case, it's not necessary and we can just go on our
 333           // merry way.
 334           int __int_bom = __state.internal_bom();
 335           if (__int_bom)
 336             {
 337               size_t __size = __from_end - __from;
 338               intern_type* __cfixed = static_cast<intern_type*>
 339                 (__builtin_alloca(sizeof(intern_type) * (__size + 1)));
 340               __cfixed[0] = static_cast<intern_type>(__int_bom);
 341               char_traits<intern_type>::copy(__cfixed + 1, __from, __size);
 342               __cfrom = reinterpret_cast<char*>(__cfixed);
 343               __conv = __iconv_adaptor(iconv, __desc, &__cfrom,
 344                                         &__fbytes, &__cto, &__tbytes);
 345             }
 346           else
 347             {
 348               intern_type* __cfixed = const_cast<intern_type*>(__from);
 349               __cfrom = reinterpret_cast<char*>(__cfixed);
 350               __conv = __iconv_adaptor(iconv, __desc, &__cfrom, &__fbytes,
 351                                        &__cto, &__tbytes);
 352             }
 353
 354           if (__conv != size_t(-1))
 355             {
 356               __from_next = reinterpret_cast<const intern_type*>(__cfrom);
 357               __to_next = reinterpret_cast<extern_type*>(__cto);
 358               __ret = codecvt_base::ok;
 359             }
 360           else
 361             {
 362               if (__fbytes < __fmultiple * (__from_end - __from))
 363                 {
 364                   __from_next = reinterpret_cast<const intern_type*>(__cfrom);
 365                   __to_next = reinterpret_cast<extern_type*>(__cto);
 366                   __ret = codecvt_base::partial;
 367                 }
 368               else
 369                 __ret = codecvt_base::error;
 370             }
 371         }
 372       return __ret;
 373     }
 374
 375   template<typename _InternT, typename _ExternT>
 376     codecvt_base::result
 377     codecvt<_InternT, _ExternT, encoding_state>::
 378     do_unshift(state_type& __state, extern_type* __to,
 379                extern_type* __to_end, extern_type*& __to_next) const
 380     {
 381       result __ret = codecvt_base::error;
 382       if (__state.good())
 383         {
 384           const descriptor_type& __desc = __state.in_descriptor();
 385           const size_t __tmultiple = sizeof(intern_type);
 386           size_t __tlen = __tmultiple * (__to_end - __to);
 387
 388           // Argument list for iconv specifies a byte sequence. Thus,
 389           // all to/from arrays must be brutally casted to char*.
 390           char* __cto = reinterpret_cast<char*>(__to);
 391           size_t __conv = __iconv_adaptor(iconv,__desc, 0, 0,
 392                                           &__cto, &__tlen);
 393
 394           if (__conv != size_t(-1))
 395             {
 396               __to_next = reinterpret_cast<extern_type*>(__cto);
 397               if (__tlen == __tmultiple * (__to_end - __to))
 398                 __ret = codecvt_base::noconv;
 399               else if (__tlen == 0)
 400                 __ret = codecvt_base::ok;
 401               else
 402                 __ret = codecvt_base::partial;
 403             }
 404           else
 405             __ret = codecvt_base::error;
 406         }
 407       return __ret;
 408     }
 409
 410   template<typename _InternT, typename _ExternT>
 411     codecvt_base::result
 412     codecvt<_InternT, _ExternT, encoding_state>::
 413     do_in(state_type& __state, const extern_type* __from,
 414           const extern_type* __from_end, const extern_type*& __from_next,
 415           intern_type* __to, intern_type* __to_end,
 416           intern_type*& __to_next) const
 417     {
 418       result __ret = codecvt_base::error;
 419       if (__state.good())
 420         {
 421           const descriptor_type& __desc = __state.in_descriptor();
 422           const size_t __fmultiple = sizeof(extern_type);
 423           size_t __flen = __fmultiple * (__from_end - __from);
 424           const size_t __tmultiple = sizeof(intern_type);
 425           size_t __tlen = __tmultiple * (__to_end - __to);
 426
 427           // Argument list for iconv specifies a byte sequence. Thus,
 428           // all to/from arrays must be brutally casted to char*.
 429           char* __cto = reinterpret_cast<char*>(__to);
 430           char* __cfrom;
 431           size_t __conv;
 432
 433           // Some encodings need a byte order marker as the first item
 434           // in the byte stream, to designate endian-ness. The default
 435           // value for the byte order marker is NULL, so if this is
 436           // the case, it's not necessary and we can just go on our
 437           // merry way.
 438           int __ext_bom = __state.external_bom();
 439           if (__ext_bom)
 440             {
 441               size_t __size = __from_end - __from;
 442               extern_type* __cfixed =  static_cast<extern_type*>
 443                 (__builtin_alloca(sizeof(extern_type) * (__size + 1)));
 444               __cfixed[0] = static_cast<extern_type>(__ext_bom);
 445               char_traits<extern_type>::copy(__cfixed + 1, __from, __size);
 446               __cfrom = reinterpret_cast<char*>(__cfixed);
 447               __conv = __iconv_adaptor(iconv, __desc, &__cfrom,
 448                                        &__flen, &__cto, &__tlen);
 449             }
 450           else
 451             {
 452               extern_type* __cfixed = const_cast<extern_type*>(__from);
 453               __cfrom = reinterpret_cast<char*>(__cfixed);
 454               __conv = __iconv_adaptor(iconv, __desc, &__cfrom,
 455                                        &__flen, &__cto, &__tlen);
 456             }
 457
 458
 459           if (__conv != size_t(-1))
 460             {
 461               __from_next = reinterpret_cast<const extern_type*>(__cfrom);
 462               __to_next = reinterpret_cast<intern_type*>(__cto);
 463               __ret = codecvt_base::ok;
 464             }
 465           else
 466             {
 467               if (__flen < static_cast<size_t>(__from_end - __from))
 468                 {
 469                   __from_next = reinterpret_cast<const extern_type*>(__cfrom);
 470                   __to_next = reinterpret_cast<intern_type*>(__cto);
 471                   __ret = codecvt_base::partial;
 472                 }
 473               else
 474                 __ret = codecvt_base::error;
 475             }
 476         }
 477       return __ret;
 478     }
 479
 480   template<typename _InternT, typename _ExternT>
 481     int
 482     codecvt<_InternT, _ExternT, encoding_state>::
 483     do_encoding() const throw()
 484     {
 485       int __ret = 0;
 486       if (sizeof(_ExternT) <= sizeof(_InternT))
 487         __ret = sizeof(_InternT) / sizeof(_ExternT);
 488       return __ret;
 489     }
 490
 491   template<typename _InternT, typename _ExternT>
 492     bool
 493     codecvt<_InternT, _ExternT, encoding_state>::
 494     do_always_noconv() const throw()
 495     { return false; }
 496
 497   template<typename _InternT, typename _ExternT>
 498     int
 499     codecvt<_InternT, _ExternT, encoding_state>::
 500     do_length(state_type&, const extern_type* __from,
 501               const extern_type* __end, size_t __max) const
 502     { return std::min(__max, static_cast<size_t>(__end - __from)); }
 503
 504   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 505   // 74.  Garbled text for codecvt::do_max_length
 506   template<typename _InternT, typename _ExternT>
 507     int
 508     codecvt<_InternT, _ExternT, encoding_state>::
 509     do_max_length() const throw()
 510     { return 1; }
 511
 512 _GLIBCXX_END_NAMESPACE_VERSION
 513 } // namespace
 514
 515 #endif