libstdc++-v3/include/bits/locale_conv.h

   1 // wstring_convert implementation -*- C++ -*-
   2
   3 // Copyright (C) 2015-2018 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 /** @file bits/locale_conv.h
  26  *  This is an internal header file, included by other library headers.
  27  *  Do not attempt to use it directly. @headername{locale}
  28  */
  29
  30 #ifndef _LOCALE_CONV_H
  31 #define _LOCALE_CONV_H 1
  32
  33 #if __cplusplus < 201103L
  34 # include <bits/c++0x_warning.h>
  35 #else
  36
  37 #include <streambuf>
  38 #include "stringfwd.h"
  39 #include "allocator.h"
  40 #include "codecvt.h"
  41 #include "unique_ptr.h"
  42
  43 namespace std _GLIBCXX_VISIBILITY(default)
  44 {
  45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  46
  47   /**
  48    * @addtogroup locales
  49    * @{
  50    */
  51
  52   template<typename _OutStr, typename _InChar, typename _Codecvt,
  53            typename _State, typename _Fn>
  54     bool
  55     __do_str_codecvt(const _InChar* __first, const _InChar* __last,
  56                      _OutStr& __outstr, const _Codecvt& __cvt, _State& __state,
  57                      size_t& __count, _Fn __fn)
  58     {
  59       if (__first == __last)
  60         {
  61           __outstr.clear();
  62           __count = 0;
  63           return true;
  64         }
  65
  66       size_t __outchars = 0;
  67       auto __next = __first;
  68       const auto __maxlen = __cvt.max_length() + 1;
  69
  70       codecvt_base::result __result;
  71       do
  72         {
  73           __outstr.resize(__outstr.size() + (__last - __next) * __maxlen);
  74           auto __outnext = &__outstr.front() + __outchars;
  75           auto const __outlast = &__outstr.back() + 1;
  76           __result = (__cvt.*__fn)(__state, __next, __last, __next,
  77                                         __outnext, __outlast, __outnext);
  78           __outchars = __outnext - &__outstr.front();
  79         }
  80       while (__result == codecvt_base::partial && __next != __last
  81              && (__outstr.size() - __outchars) < __maxlen);
  82
  83       if (__result == codecvt_base::error)
  84         {
  85           __count = __next - __first;
  86           return false;
  87         }
  88
  89       if (__result == codecvt_base::noconv)
  90         {
  91           __outstr.assign(__first, __last);
  92           __count = __last - __first;
  93         }
  94       else
  95         {
  96           __outstr.resize(__outchars);
  97           __count = __next - __first;
  98         }
  99
 100       return true;
 101     }
 102
 103   // Convert narrow character string to wide.
 104   template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
 105     inline bool
 106     __str_codecvt_in(const char* __first, const char* __last,
 107                      basic_string<_CharT, _Traits, _Alloc>& __outstr,
 108                      const codecvt<_CharT, char, _State>& __cvt,
 109                      _State& __state, size_t& __count)
 110     {
 111       using _Codecvt = codecvt<_CharT, char, _State>;
 112       using _ConvFn
 113         = codecvt_base::result
 114           (_Codecvt::*)(_State&, const char*, const char*, const char*&,
 115                         _CharT*, _CharT*, _CharT*&) const;
 116       _ConvFn __fn = &codecvt<_CharT, char, _State>::in;
 117       return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
 118                               __count, __fn);
 119     }
 120
 121   template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
 122     inline bool
 123     __str_codecvt_in(const char* __first, const char* __last,
 124                      basic_string<_CharT, _Traits, _Alloc>& __outstr,
 125                      const codecvt<_CharT, char, _State>& __cvt)
 126     {
 127       _State __state = {};
 128       size_t __n;
 129       return __str_codecvt_in(__first, __last, __outstr, __cvt, __state, __n);
 130     }
 131
 132   // Convert wide character string to narrow.
 133   template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
 134     inline bool
 135     __str_codecvt_out(const _CharT* __first, const _CharT* __last,
 136                       basic_string<char, _Traits, _Alloc>& __outstr,
 137                       const codecvt<_CharT, char, _State>& __cvt,
 138                       _State& __state, size_t& __count)
 139     {
 140       using _Codecvt = codecvt<_CharT, char, _State>;
 141       using _ConvFn
 142         = codecvt_base::result
 143           (_Codecvt::*)(_State&, const _CharT*, const _CharT*, const _CharT*&,
 144                         char*, char*, char*&) const;
 145       _ConvFn __fn = &codecvt<_CharT, char, _State>::out;
 146       return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
 147                               __count, __fn);
 148     }
 149
 150   template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
 151     inline bool
 152     __str_codecvt_out(const _CharT* __first, const _CharT* __last,
 153                       basic_string<char, _Traits, _Alloc>& __outstr,
 154                       const codecvt<_CharT, char, _State>& __cvt)
 155     {
 156       _State __state = {};
 157       size_t __n;
 158       return __str_codecvt_out(__first, __last, __outstr, __cvt, __state, __n);
 159     }
 160
 161 #ifdef _GLIBCXX_USE_WCHAR_T
 162
 163 _GLIBCXX_BEGIN_NAMESPACE_CXX11
 164
 165   /// String conversions
 166   template<typename _Codecvt, typename _Elem = wchar_t,
 167            typename _Wide_alloc = allocator<_Elem>,
 168            typename _Byte_alloc = allocator<char>>
 169     class wstring_convert
 170     {
 171     public:
 172       typedef basic_string<char, char_traits<char>, _Byte_alloc>   byte_string;
 173       typedef basic_string<_Elem, char_traits<_Elem>, _Wide_alloc> wide_string;
 174       typedef typename _Codecvt::state_type                        state_type;
 175       typedef typename wide_string::traits_type::int_type          int_type;
 176
 177       /** Default constructor.
 178        *
 179        * @param  __pcvt The facet to use for conversions.
 180        *
 181        * Takes ownership of @p __pcvt and will delete it in the destructor.
 182        */
 183       explicit
 184       wstring_convert(_Codecvt* __pcvt = new _Codecvt()) : _M_cvt(__pcvt)
 185       {
 186         if (!_M_cvt)
 187           __throw_logic_error("wstring_convert");
 188       }
 189
 190       /** Construct with an initial converstion state.
 191        *
 192        * @param  __pcvt The facet to use for conversions.
 193        * @param  __state Initial conversion state.
 194        *
 195        * Takes ownership of @p __pcvt and will delete it in the destructor.
 196        * The object's conversion state will persist between conversions.
 197        */
 198       wstring_convert(_Codecvt* __pcvt, state_type __state)
 199       : _M_cvt(__pcvt), _M_state(__state), _M_with_cvtstate(true)
 200       {
 201         if (!_M_cvt)
 202           __throw_logic_error("wstring_convert");
 203       }
 204
 205       /** Construct with error strings.
 206        *
 207        * @param  __byte_err A string to return on failed conversions.
 208        * @param  __wide_err A wide string to return on failed conversions.
 209        */
 210       explicit
 211       wstring_convert(const byte_string& __byte_err,
 212                       const wide_string& __wide_err = wide_string())
 213       : _M_cvt(new _Codecvt),
 214         _M_byte_err_string(__byte_err), _M_wide_err_string(__wide_err),
 215         _M_with_strings(true)
 216       {
 217         if (!_M_cvt)
 218           __throw_logic_error("wstring_convert");
 219       }
 220
 221       ~wstring_convert() = default;
 222
 223       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 224       // 2176. Special members for wstring_convert and wbuffer_convert
 225       wstring_convert(const wstring_convert&) = delete;
 226       wstring_convert& operator=(const wstring_convert&) = delete;
 227
 228       /// @{ Convert from bytes.
 229       wide_string
 230       from_bytes(char __byte)
 231       {
 232         char __bytes[2] = { __byte };
 233         return from_bytes(__bytes, __bytes+1);
 234       }
 235
 236       wide_string
 237       from_bytes(const char* __ptr)
 238       { return from_bytes(__ptr, __ptr+char_traits<char>::length(__ptr)); }
 239
 240       wide_string
 241       from_bytes(const byte_string& __str)
 242       {
 243         auto __ptr = __str.data();
 244         return from_bytes(__ptr, __ptr + __str.size());
 245       }
 246
 247       wide_string
 248       from_bytes(const char* __first, const char* __last)
 249       {
 250         if (!_M_with_cvtstate)
 251           _M_state = state_type();
 252         wide_string __out{ _M_wide_err_string.get_allocator() };
 253         if (__str_codecvt_in(__first, __last, __out, *_M_cvt, _M_state,
 254                              _M_count))
 255           return __out;
 256         if (_M_with_strings)
 257           return _M_wide_err_string;
 258         __throw_range_error("wstring_convert::from_bytes");
 259       }
 260       /// @}
 261
 262       /// @{ Convert to bytes.
 263       byte_string
 264       to_bytes(_Elem __wchar)
 265       {
 266         _Elem __wchars[2] = { __wchar };
 267         return to_bytes(__wchars, __wchars+1);
 268       }
 269
 270       byte_string
 271       to_bytes(const _Elem* __ptr)
 272       {
 273         return to_bytes(__ptr, __ptr+wide_string::traits_type::length(__ptr));
 274       }
 275
 276       byte_string
 277       to_bytes(const wide_string& __wstr)
 278       {
 279         auto __ptr = __wstr.data();
 280         return to_bytes(__ptr, __ptr + __wstr.size());
 281       }
 282
 283       byte_string
 284       to_bytes(const _Elem* __first, const _Elem* __last)
 285       {
 286         if (!_M_with_cvtstate)
 287           _M_state = state_type();
 288         byte_string __out{ _M_byte_err_string.get_allocator() };
 289         if (__str_codecvt_out(__first, __last, __out, *_M_cvt, _M_state,
 290                               _M_count))
 291           return __out;
 292         if (_M_with_strings)
 293           return _M_byte_err_string;
 294         __throw_range_error("wstring_convert::to_bytes");
 295       }
 296       /// @}
 297
 298       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 299       // 2174. wstring_convert::converted() should be noexcept
 300       /// The number of elements successfully converted in the last conversion.
 301       size_t converted() const noexcept { return _M_count; }
 302
 303       /// The final conversion state of the last conversion.
 304       state_type state() const { return _M_state; }
 305
 306     private:
 307       unique_ptr<_Codecvt>      _M_cvt;
 308       byte_string               _M_byte_err_string;
 309       wide_string               _M_wide_err_string;
 310       state_type                _M_state = state_type();
 311       size_t                    _M_count = 0;
 312       bool                      _M_with_cvtstate = false;
 313       bool                      _M_with_strings = false;
 314     };
 315
 316 _GLIBCXX_END_NAMESPACE_CXX11
 317
 318   /// Buffer conversions
 319   template<typename _Codecvt, typename _Elem = wchar_t,
 320            typename _Tr = char_traits<_Elem>>
 321     class wbuffer_convert : public basic_streambuf<_Elem, _Tr>
 322     {
 323       typedef basic_streambuf<_Elem, _Tr> _Wide_streambuf;
 324
 325     public:
 326       typedef typename _Codecvt::state_type state_type;
 327
 328       /** Default constructor.
 329        *
 330        * @param  __bytebuf The underlying byte stream buffer.
 331        * @param  __pcvt    The facet to use for conversions.
 332        * @param  __state   Initial conversion state.
 333        *
 334        * Takes ownership of @p __pcvt and will delete it in the destructor.
 335        */
 336       explicit
 337       wbuffer_convert(streambuf* __bytebuf = 0, _Codecvt* __pcvt = new _Codecvt,
 338                       state_type __state = state_type())
 339       : _M_buf(__bytebuf), _M_cvt(__pcvt), _M_state(__state)
 340       {
 341         if (!_M_cvt)
 342           __throw_logic_error("wbuffer_convert");
 343
 344         _M_always_noconv = _M_cvt->always_noconv();
 345
 346         if (_M_buf)
 347           {
 348             this->setp(_M_put_area, _M_put_area + _S_buffer_length);
 349             this->setg(_M_get_area + _S_putback_length,
 350                        _M_get_area + _S_putback_length,
 351                        _M_get_area + _S_putback_length);
 352           }
 353       }
 354
 355       ~wbuffer_convert() = default;
 356
 357       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 358       // 2176. Special members for wstring_convert and wbuffer_convert
 359       wbuffer_convert(const wbuffer_convert&) = delete;
 360       wbuffer_convert& operator=(const wbuffer_convert&) = delete;
 361
 362       streambuf* rdbuf() const noexcept { return _M_buf; }
 363
 364       streambuf*
 365       rdbuf(streambuf *__bytebuf) noexcept
 366       {
 367         auto __prev = _M_buf;
 368         _M_buf = __bytebuf;
 369         return __prev;
 370       }
 371
 372       /// The conversion state following the last conversion.
 373       state_type state() const noexcept { return _M_state; }
 374
 375     protected:
 376       int
 377       sync()
 378       { return _M_buf && _M_conv_put() && !_M_buf->pubsync() ? 0 : -1; }
 379
 380       typename _Wide_streambuf::int_type
 381       overflow(typename _Wide_streambuf::int_type __out)
 382       {
 383         if (!_M_buf || !_M_conv_put())
 384           return _Tr::eof();
 385         else if (!_Tr::eq_int_type(__out, _Tr::eof()))
 386           return this->sputc(__out);
 387         return _Tr::not_eof(__out);
 388       }
 389
 390       typename _Wide_streambuf::int_type
 391       underflow()
 392       {
 393         if (!_M_buf)
 394           return _Tr::eof();
 395
 396         if (this->gptr() < this->egptr() || (_M_buf && _M_conv_get()))
 397           return _Tr::to_int_type(*this->gptr());
 398         else
 399           return _Tr::eof();
 400       }
 401
 402       streamsize
 403       xsputn(const typename _Wide_streambuf::char_type* __s, streamsize __n)
 404       {
 405         if (!_M_buf || __n == 0)
 406           return 0;
 407         streamsize __done = 0;
 408         do
 409         {
 410           auto __nn = std::min<streamsize>(this->epptr() - this->pptr(),
 411                                            __n - __done);
 412           _Tr::copy(this->pptr(), __s + __done, __nn);
 413           this->pbump(__nn);
 414           __done += __nn;
 415         } while (__done < __n && _M_conv_put());
 416         return __done;
 417       }
 418
 419     private:
 420       // fill the get area from converted contents of the byte stream buffer
 421       bool
 422       _M_conv_get()
 423       {
 424         const streamsize __pb1 = this->gptr() - this->eback();
 425         const streamsize __pb2 = _S_putback_length;
 426         const streamsize __npb = std::min(__pb1, __pb2);
 427
 428         _Tr::move(_M_get_area + _S_putback_length - __npb,
 429                   this->gptr() - __npb, __npb);
 430
 431         streamsize __nbytes = sizeof(_M_get_buf) - _M_unconv;
 432         __nbytes = std::min(__nbytes, _M_buf->in_avail());
 433         if (__nbytes < 1)
 434           __nbytes = 1;
 435         __nbytes = _M_buf->sgetn(_M_get_buf + _M_unconv, __nbytes);
 436         if (__nbytes < 1)
 437           return false;
 438         __nbytes += _M_unconv;
 439
 440         // convert _M_get_buf into _M_get_area
 441
 442         _Elem* __outbuf = _M_get_area + _S_putback_length;
 443         _Elem* __outnext = __outbuf;
 444         const char* __bnext = _M_get_buf;
 445
 446         codecvt_base::result __result;
 447         if (_M_always_noconv)
 448           __result = codecvt_base::noconv;
 449         else
 450           {
 451             _Elem* __outend = _M_get_area + _S_buffer_length;
 452
 453             __result = _M_cvt->in(_M_state,
 454                                   __bnext, __bnext + __nbytes, __bnext,
 455                                   __outbuf, __outend, __outnext);
 456           }
 457
 458         if (__result == codecvt_base::noconv)
 459           {
 460             // cast is safe because noconv means _Elem is same type as char
 461             auto __get_buf = reinterpret_cast<const _Elem*>(_M_get_buf);
 462             _Tr::copy(__outbuf, __get_buf, __nbytes);
 463             _M_unconv = 0;
 464             return true;
 465           }
 466
 467         if ((_M_unconv = _M_get_buf + __nbytes - __bnext))
 468           char_traits<char>::move(_M_get_buf, __bnext, _M_unconv);
 469
 470         this->setg(__outbuf, __outbuf, __outnext);
 471
 472         return __result != codecvt_base::error;
 473       }
 474
 475       // unused
 476       bool
 477       _M_put(...)
 478       { return false; }
 479
 480       bool
 481       _M_put(const char* __p, streamsize __n)
 482       {
 483         if (_M_buf->sputn(__p, __n) < __n)
 484           return false;
 485         return true;
 486       }
 487
 488       // convert the put area and write to the byte stream buffer
 489       bool
 490       _M_conv_put()
 491       {
 492         _Elem* const __first = this->pbase();
 493         const _Elem* const __last = this->pptr();
 494         const streamsize __pending = __last - __first;
 495
 496         if (_M_always_noconv)
 497           return _M_put(__first, __pending);
 498
 499         char __outbuf[2 * _S_buffer_length];
 500
 501         const _Elem* __next = __first;
 502         const _Elem* __start;
 503         do
 504           {
 505             __start = __next;
 506             char* __outnext = __outbuf;
 507             char* const __outlast = __outbuf + sizeof(__outbuf);
 508             auto __result = _M_cvt->out(_M_state, __next, __last, __next,
 509                                         __outnext, __outlast, __outnext);
 510             if (__result == codecvt_base::error)
 511               return false;
 512             else if (__result == codecvt_base::noconv)
 513               return _M_put(__next, __pending);
 514
 515             if (!_M_put(__outbuf, __outnext - __outbuf))
 516               return false;
 517           }
 518         while (__next != __last && __next != __start);
 519
 520         if (__next != __last)
 521           _Tr::move(__first, __next, __last - __next);
 522
 523         this->pbump(__first - __next);
 524         return __next != __first;
 525       }
 526
 527       streambuf*                _M_buf;
 528       unique_ptr<_Codecvt>      _M_cvt;
 529       state_type                _M_state;
 530
 531       static const streamsize   _S_buffer_length = 32;
 532       static const streamsize   _S_putback_length = 3;
 533       _Elem                     _M_put_area[_S_buffer_length];
 534       _Elem                     _M_get_area[_S_buffer_length];
 535       streamsize                _M_unconv = 0;
 536       char                      _M_get_buf[_S_buffer_length-_S_putback_length];
 537       bool                      _M_always_noconv;
 538     };
 539
 540 #endif  // _GLIBCXX_USE_WCHAR_T
 541
 542   /// @} group locales
 543
 544 _GLIBCXX_END_NAMESPACE_VERSION
 545 } // namespace
 546
 547 #endif // __cplusplus
 548
 549 #endif /* _LOCALE_CONV_H */