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

   1 // wstring_convert implementation -*- C++ -*-
   2
   3 // Copyright (C) 2015-2016 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         return false;
  85
  86       if (__result == codecvt_base::noconv)
  87         {
  88           __outstr.assign(__first, __last);
  89           __count = __last - __first;
  90         }
  91       else
  92         {
  93           __outstr.resize(__outchars);
  94           __count = __next - __first;
  95         }
  96
  97       return true;
  98     }
  99
 100   // Convert narrow character string to wide.
 101   template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
 102     inline bool
 103     __str_codecvt_in(const char* __first, const char* __last,
 104                      basic_string<_CharT, _Traits, _Alloc>& __outstr,
 105                      const codecvt<_CharT, char, _State>& __cvt,
 106                      _State& __state, size_t& __count)
 107     {
 108       using _Codecvt = codecvt<_CharT, char, _State>;
 109       using _ConvFn
 110         = codecvt_base::result
 111           (_Codecvt::*)(_State&, const char*, const char*, const char*&,
 112                         _CharT*, _CharT*, _CharT*&) const;
 113       _ConvFn __fn = &codecvt<_CharT, char, _State>::in;
 114       return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
 115                               __count, __fn);
 116     }
 117
 118   template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
 119     inline bool
 120     __str_codecvt_in(const char* __first, const char* __last,
 121                      basic_string<_CharT, _Traits, _Alloc>& __outstr,
 122                      const codecvt<_CharT, char, _State>& __cvt)
 123     {
 124       _State __state = {};
 125       size_t __n;
 126       return __str_codecvt_in(__first, __last, __outstr, __cvt, __state, __n);
 127     }
 128
 129   // Convert wide character string to narrow.
 130   template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
 131     inline bool
 132     __str_codecvt_out(const _CharT* __first, const _CharT* __last,
 133                       basic_string<char, _Traits, _Alloc>& __outstr,
 134                       const codecvt<_CharT, char, _State>& __cvt,
 135                       _State& __state, size_t& __count)
 136     {
 137       using _Codecvt = codecvt<_CharT, char, _State>;
 138       using _ConvFn
 139         = codecvt_base::result
 140           (_Codecvt::*)(_State&, const _CharT*, const _CharT*, const _CharT*&,
 141                         char*, char*, char*&) const;
 142       _ConvFn __fn = &codecvt<_CharT, char, _State>::out;
 143       return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
 144                               __count, __fn);
 145     }
 146
 147   template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
 148     inline bool
 149     __str_codecvt_out(const _CharT* __first, const _CharT* __last,
 150                       basic_string<char, _Traits, _Alloc>& __outstr,
 151                       const codecvt<_CharT, char, _State>& __cvt)
 152     {
 153       _State __state = {};
 154       size_t __n;
 155       return __str_codecvt_out(__first, __last, __outstr, __cvt, __state, __n);
 156     }
 157
 158 #ifdef _GLIBCXX_USE_WCHAR_T
 159
 160 _GLIBCXX_BEGIN_NAMESPACE_CXX11
 161
 162   /// String conversions
 163   template<typename _Codecvt, typename _Elem = wchar_t,
 164            typename _Wide_alloc = allocator<_Elem>,
 165            typename _Byte_alloc = allocator<char>>
 166     class wstring_convert
 167     {
 168     public:
 169       typedef basic_string<char, char_traits<char>, _Byte_alloc>   byte_string;
 170       typedef basic_string<_Elem, char_traits<_Elem>, _Wide_alloc> wide_string;
 171       typedef typename _Codecvt::state_type                        state_type;
 172       typedef typename wide_string::traits_type::int_type          int_type;
 173
 174       /** Default constructor.
 175        *
 176        * @param  __pcvt The facet to use for conversions.
 177        *
 178        * Takes ownership of @p __pcvt and will delete it in the destructor.
 179        */
 180       explicit
 181       wstring_convert(_Codecvt* __pcvt = new _Codecvt()) : _M_cvt(__pcvt)
 182       {
 183         if (!_M_cvt)
 184           __throw_logic_error("wstring_convert");
 185       }
 186
 187       /** Construct with an initial converstion state.
 188        *
 189        * @param  __pcvt The facet to use for conversions.
 190        * @param  __state Initial conversion state.
 191        *
 192        * Takes ownership of @p __pcvt and will delete it in the destructor.
 193        * The object's conversion state will persist between conversions.
 194        */
 195       wstring_convert(_Codecvt* __pcvt, state_type __state)
 196       : _M_cvt(__pcvt), _M_state(__state), _M_with_cvtstate(true)
 197       {
 198         if (!_M_cvt)
 199           __throw_logic_error("wstring_convert");
 200       }
 201
 202       /** Construct with error strings.
 203        *
 204        * @param  __byte_err A string to return on failed conversions.
 205        * @param  __wide_err A wide string to return on failed conversions.
 206        */
 207       explicit
 208       wstring_convert(const byte_string& __byte_err,
 209                       const wide_string& __wide_err = wide_string())
 210       : _M_cvt(new _Codecvt),
 211         _M_byte_err_string(__byte_err), _M_wide_err_string(__wide_err),
 212         _M_with_strings(true)
 213       {
 214         if (!_M_cvt)
 215           __throw_logic_error("wstring_convert");
 216       }
 217
 218       ~wstring_convert() = default;
 219
 220       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 221       // 2176. Special members for wstring_convert and wbuffer_convert
 222       wstring_convert(const wstring_convert&) = delete;
 223       wstring_convert& operator=(const wstring_convert&) = delete;
 224
 225       /// @{ Convert from bytes.
 226       wide_string
 227       from_bytes(char __byte)
 228       {
 229         char __bytes[2] = { __byte };
 230         return from_bytes(__bytes, __bytes+1);
 231       }
 232
 233       wide_string
 234       from_bytes(const char* __ptr)
 235       { return from_bytes(__ptr, __ptr+char_traits<char>::length(__ptr)); }
 236
 237       wide_string
 238       from_bytes(const byte_string& __str)
 239       {
 240         auto __ptr = __str.data();
 241         return from_bytes(__ptr, __ptr + __str.size());
 242       }
 243
 244       wide_string
 245       from_bytes(const char* __first, const char* __last)
 246       {
 247         if (!_M_with_cvtstate)
 248           _M_state = state_type();
 249         wide_string __out{ _M_wide_err_string.get_allocator() };
 250         if (__str_codecvt_in(__first, __last, __out, *_M_cvt, _M_state,
 251                              _M_count))
 252           return __out;
 253         if (_M_with_strings)
 254           return _M_wide_err_string;
 255         __throw_range_error("wstring_convert::from_bytes");
 256       }
 257       /// @}
 258
 259       /// @{ Convert to bytes.
 260       byte_string
 261       to_bytes(_Elem __wchar)
 262       {
 263         _Elem __wchars[2] = { __wchar };
 264         return to_bytes(__wchars, __wchars+1);
 265       }
 266
 267       byte_string
 268       to_bytes(const _Elem* __ptr)
 269       {
 270         return to_bytes(__ptr, __ptr+wide_string::traits_type::length(__ptr));
 271       }
 272
 273       byte_string
 274       to_bytes(const wide_string& __wstr)
 275       {
 276         auto __ptr = __wstr.data();
 277         return to_bytes(__ptr, __ptr + __wstr.size());
 278       }
 279
 280       byte_string
 281       to_bytes(const _Elem* __first, const _Elem* __last)
 282       {
 283         if (!_M_with_cvtstate)
 284           _M_state = state_type();
 285         byte_string __out{ _M_byte_err_string.get_allocator() };
 286         if (__str_codecvt_out(__first, __last, __out, *_M_cvt, _M_state,
 287                               _M_count))
 288           return __out;
 289         if (_M_with_strings)
 290           return _M_byte_err_string;
 291         __throw_range_error("wstring_convert::to_bytes");
 292       }
 293       /// @}
 294
 295       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 296       // 2174. wstring_convert::converted() should be noexcept
 297       /// The number of elements successfully converted in the last conversion.
 298       size_t converted() const noexcept { return _M_count; }
 299
 300       /// The final conversion state of the last conversion.
 301       state_type state() const { return _M_state; }
 302
 303     private:
 304       unique_ptr<_Codecvt>      _M_cvt;
 305       byte_string               _M_byte_err_string;
 306       wide_string               _M_wide_err_string;
 307       state_type                _M_state = state_type();
 308       size_t                    _M_count = 0;
 309       bool                      _M_with_cvtstate = false;
 310       bool                      _M_with_strings = false;
 311     };
 312
 313 _GLIBCXX_END_NAMESPACE_CXX11
 314
 315   /// Buffer conversions
 316   template<typename _Codecvt, typename _Elem = wchar_t,
 317            typename _Tr = char_traits<_Elem>>
 318     class wbuffer_convert : public basic_streambuf<_Elem, _Tr>
 319     {
 320       typedef basic_streambuf<_Elem, _Tr> _Wide_streambuf;
 321
 322     public:
 323       typedef typename _Codecvt::state_type state_type;
 324
 325       /** Default constructor.
 326        *
 327        * @param  __bytebuf The underlying byte stream buffer.
 328        * @param  __pcvt    The facet to use for conversions.
 329        * @param  __state   Initial conversion state.
 330        *
 331        * Takes ownership of @p __pcvt and will delete it in the destructor.
 332        */
 333       explicit
 334       wbuffer_convert(streambuf* __bytebuf = 0, _Codecvt* __pcvt = new _Codecvt,
 335                       state_type __state = state_type())
 336       : _M_buf(__bytebuf), _M_cvt(__pcvt), _M_state(__state)
 337       {
 338         if (!_M_cvt)
 339           __throw_logic_error("wbuffer_convert");
 340
 341         _M_always_noconv = _M_cvt->always_noconv();
 342
 343         if (_M_buf)
 344           {
 345             this->setp(_M_put_area, _M_put_area + _S_buffer_length);
 346             this->setg(_M_get_area + _S_putback_length,
 347                        _M_get_area + _S_putback_length,
 348                        _M_get_area + _S_putback_length);
 349           }
 350       }
 351
 352       ~wbuffer_convert() = default;
 353
 354       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 355       // 2176. Special members for wstring_convert and wbuffer_convert
 356       wbuffer_convert(const wbuffer_convert&) = delete;
 357       wbuffer_convert& operator=(const wbuffer_convert&) = delete;
 358
 359       streambuf* rdbuf() const noexcept { return _M_buf; }
 360
 361       streambuf*
 362       rdbuf(streambuf *__bytebuf) noexcept
 363       {
 364         auto __prev = _M_buf;
 365         _M_buf = __bytebuf;
 366         return __prev;
 367       }
 368
 369       /// The conversion state following the last conversion.
 370       state_type state() const noexcept { return _M_state; }
 371
 372     protected:
 373       int
 374       sync()
 375       { return _M_buf && _M_conv_put() && _M_buf->pubsync() ? 0 : -1; }
 376
 377       typename _Wide_streambuf::int_type
 378       overflow(typename _Wide_streambuf::int_type __out)
 379       {
 380         if (!_M_buf || !_M_conv_put())
 381           return _Tr::eof();
 382         else if (!_Tr::eq_int_type(__out, _Tr::eof()))
 383           return this->sputc(__out);
 384         return _Tr::not_eof(__out);
 385       }
 386
 387       typename _Wide_streambuf::int_type
 388       underflow()
 389       {
 390         if (!_M_buf)
 391           return _Tr::eof();
 392
 393         if (this->gptr() < this->egptr() || (_M_buf && _M_conv_get()))
 394           return _Tr::to_int_type(*this->gptr());
 395         else
 396           return _Tr::eof();
 397       }
 398
 399       streamsize
 400       xsputn(const typename _Wide_streambuf::char_type* __s, streamsize __n)
 401       {
 402         if (!_M_buf || __n == 0)
 403           return 0;
 404         streamsize __done = 0;
 405         do
 406         {
 407           auto __nn = std::min<streamsize>(this->epptr() - this->pptr(),
 408                                            __n - __done);
 409           _Tr::copy(this->pptr(), __s + __done, __nn);
 410           this->pbump(__nn);
 411           __done += __nn;
 412         } while (__done < __n && _M_conv_put());
 413         return __done;
 414       }
 415
 416     private:
 417       // fill the get area from converted contents of the byte stream buffer
 418       bool
 419       _M_conv_get()
 420       {
 421         const streamsize __pb1 = this->gptr() - this->eback();
 422         const streamsize __pb2 = _S_putback_length;
 423         const streamsize __npb = std::min(__pb1, __pb2);
 424
 425         _Tr::move(_M_get_area + _S_putback_length - __npb,
 426                   this->gptr() - __npb, __npb);
 427
 428         streamsize __nbytes = sizeof(_M_get_buf) - _M_unconv;
 429         __nbytes = std::min(__nbytes, _M_buf->in_avail());
 430         if (__nbytes < 1)
 431           __nbytes == 1;
 432         __nbytes = _M_buf->sgetn(_M_get_buf + _M_unconv, __nbytes);
 433         if (__nbytes < 1)
 434           return false;
 435         __nbytes += _M_unconv;
 436
 437         // convert _M_get_buf into _M_get_area
 438
 439         _Elem* __outbuf = _M_get_area + _S_putback_length;
 440         _Elem* __outnext = __outbuf;
 441         const char* __bnext = _M_get_buf;
 442
 443         codecvt_base::result __result;
 444         if (_M_always_noconv)
 445           __result = codecvt_base::noconv;
 446         else
 447           {
 448             _Elem* __outend = _M_get_area + _S_buffer_length;
 449
 450             __result = _M_cvt->in(_M_state,
 451                                   __bnext, __bnext + __nbytes, __bnext,
 452                                   __outbuf, __outend, __outnext);
 453           }
 454
 455         if (__result == codecvt_base::noconv)
 456           {
 457             // cast is safe because noconv means _Elem is same type as char
 458             auto __get_buf = reinterpret_cast<const _Elem*>(_M_get_buf);
 459             _Tr::copy(__outbuf, __get_buf, __nbytes);
 460             _M_unconv = 0;
 461             return true;
 462           }
 463
 464         if ((_M_unconv = _M_get_buf + __nbytes - __bnext))
 465           char_traits<char>::move(_M_get_buf, __bnext, _M_unconv);
 466
 467         this->setg(__outbuf, __outbuf, __outnext);
 468
 469         return __result != codecvt_base::error;
 470       }
 471
 472       // unused
 473       bool
 474       _M_put(...)
 475       { return false; }
 476
 477       bool
 478       _M_put(const char* __p, streamsize __n)
 479       {
 480         if (_M_buf->sputn(__p, __n) < __n)
 481           return false;
 482       }
 483
 484       // convert the put area and write to the byte stream buffer
 485       bool
 486       _M_conv_put()
 487       {
 488         _Elem* const __first = this->pbase();
 489         const _Elem* const __last = this->pptr();
 490         const streamsize __pending = __last - __first;
 491
 492         if (_M_always_noconv)
 493           return _M_put(__first, __pending);
 494
 495         char __outbuf[2 * _S_buffer_length];
 496
 497         const _Elem* __next = __first;
 498         const _Elem* __start;
 499         do
 500           {
 501             __start = __next;
 502             char* __outnext = __outbuf;
 503             char* const __outlast = __outbuf + sizeof(__outbuf);
 504             auto __result = _M_cvt->out(_M_state, __next, __last, __next,
 505                                         __outnext, __outlast, __outnext);
 506             if (__result == codecvt_base::error)
 507               return false;
 508             else if (__result == codecvt_base::noconv)
 509               return _M_put(__next, __pending);
 510
 511             if (!_M_put(__outbuf, __outnext - __outbuf))
 512               return false;
 513           }
 514         while (__next != __last && __next != __start);
 515
 516         if (__next != __last)
 517           _Tr::move(__first, __next, __last - __next);
 518
 519         this->pbump(__first - __next);
 520         return __next != __first;
 521       }
 522
 523       streambuf*                _M_buf;
 524       unique_ptr<_Codecvt>      _M_cvt;
 525       state_type                _M_state;
 526
 527       static const streamsize   _S_buffer_length = 32;
 528       static const streamsize   _S_putback_length = 3;
 529       _Elem                     _M_put_area[_S_buffer_length];
 530       _Elem                     _M_get_area[_S_buffer_length];
 531       streamsize                _M_unconv = 0;
 532       char                      _M_get_buf[_S_buffer_length-_S_putback_length];
 533       bool                      _M_always_noconv;
 534     };
 535
 536 #endif  // _GLIBCXX_USE_WCHAR_T
 537
 538   /// @} group locales
 539
 540 _GLIBCXX_END_NAMESPACE_VERSION
 541 } // namespace
 542
 543 #endif // __cplusplus
 544
 545 #endif /* _LOCALE_CONV_H */