1// wstring_convert implementation -*- C++ -*-
2
3// Copyright (C) 2015-2024 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 <bits/stringfwd.h>
39#include <bits/allocator.h>
40#include <bits/codecvt.h>
41
42namespace std _GLIBCXX_VISIBILITY(default)
43{
44_GLIBCXX_BEGIN_NAMESPACE_VERSION
45
46 /**
47 * @addtogroup locales
48 * @{
49 */
50
51 template<typename _OutStr, typename _InChar, typename _Codecvt,
52 typename _State, typename _Fn>
53 bool
54 __do_str_codecvt(const _InChar* __first, const _InChar* __last,
55 _OutStr& __outstr, const _Codecvt& __cvt, _State& __state,
56 size_t& __count, _Fn __fn)
57 {
58 if (__first == __last)
59 {
60 __outstr.clear();
61 __count = 0;
62 return true;
63 }
64
65 size_t __outchars = 0;
66 auto __next = __first;
67 const auto __maxlen = __cvt.max_length() + 1;
68
69 codecvt_base::result __result;
70 do
71 {
72 __outstr.resize(__outstr.size() + (__last - __next) * __maxlen);
73 auto __outnext = &__outstr.front() + __outchars;
74 auto const __outlast = &__outstr.back() + 1;
75 __result = (__cvt.*__fn)(__state, __next, __last, __next,
76 __outnext, __outlast, __outnext);
77 __outchars = __outnext - &__outstr.front();
78 }
79 while (__result == codecvt_base::partial && __next != __last
80 && ptrdiff_t(__outstr.size() - __outchars) < __maxlen);
81
82 if (__result == codecvt_base::error)
83 {
84 __count = __next - __first;
85 return false;
86 }
87
88 // The codecvt facet will only return noconv when the types are
89 // the same, so avoid instantiating basic_string::assign otherwise
90 if _GLIBCXX17_CONSTEXPR (is_same<typename _Codecvt::intern_type,
91 typename _Codecvt::extern_type>())
92 if (__result == codecvt_base::noconv)
93 {
94 __outstr.assign(__first, __last);
95 __count = __last - __first;
96 return true;
97 }
98
99 __outstr.resize(__outchars);
100 __count = __next - __first;
101 return true;
102 }
103
104 // Convert narrow character string to wide.
105 template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
106 inline bool
107 __str_codecvt_in(const char* __first, const char* __last,
108 basic_string<_CharT, _Traits, _Alloc>& __outstr,
109 const codecvt<_CharT, char, _State>& __cvt,
110 _State& __state, size_t& __count)
111 {
112 using _Codecvt = codecvt<_CharT, char, _State>;
113 using _ConvFn
114 = codecvt_base::result
115 (_Codecvt::*)(_State&, const char*, const char*, const char*&,
116 _CharT*, _CharT*, _CharT*&) const;
117 _ConvFn __fn = &codecvt<_CharT, char, _State>::in;
118 return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
119 __count, __fn);
120 }
121
122 // As above, but with no __count parameter
123 template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
124 inline bool
125 __str_codecvt_in(const char* __first, const char* __last,
126 basic_string<_CharT, _Traits, _Alloc>& __outstr,
127 const codecvt<_CharT, char, _State>& __cvt)
128 {
129 _State __state = {};
130 size_t __n;
131 return __str_codecvt_in(__first, __last, __outstr, __cvt, __state, __n);
132 }
133
134 // As above, but returns false for partial conversion
135 template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
136 inline bool
137 __str_codecvt_in_all(const char* __first, const char* __last,
138 basic_string<_CharT, _Traits, _Alloc>& __outstr,
139 const codecvt<_CharT, char, _State>& __cvt)
140 {
141 _State __state = {};
142 size_t __n;
143 return __str_codecvt_in(__first, __last, __outstr, __cvt, __state, __n)
144 && (__n == size_t(__last - __first));
145 }
146
147 // Convert wide character string to narrow.
148 template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
149 inline bool
150 __str_codecvt_out(const _CharT* __first, const _CharT* __last,
151 basic_string<char, _Traits, _Alloc>& __outstr,
152 const codecvt<_CharT, char, _State>& __cvt,
153 _State& __state, size_t& __count)
154 {
155 using _Codecvt = codecvt<_CharT, char, _State>;
156 using _ConvFn
157 = codecvt_base::result
158 (_Codecvt::*)(_State&, const _CharT*, const _CharT*, const _CharT*&,
159 char*, char*, char*&) const;
160 _ConvFn __fn = &codecvt<_CharT, char, _State>::out;
161 return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
162 __count, __fn);
163 }
164
165 // As above, but with no __count parameter
166 template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
167 inline bool
168 __str_codecvt_out(const _CharT* __first, const _CharT* __last,
169 basic_string<char, _Traits, _Alloc>& __outstr,
170 const codecvt<_CharT, char, _State>& __cvt)
171 {
172 _State __state = {};
173 size_t __n;
174 return __str_codecvt_out(__first, __last, __outstr, __cvt, __state, __n);
175 }
176
177 // As above, but returns false for partial conversions
178 template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
179 inline bool
180 __str_codecvt_out_all(const _CharT* __first, const _CharT* __last,
181 basic_string<char, _Traits, _Alloc>& __outstr,
182 const codecvt<_CharT, char, _State>& __cvt)
183 {
184 _State __state = {};
185 size_t __n;
186 return __str_codecvt_out(__first, __last, __outstr, __cvt, __state, __n)
187 && (__n == size_t(__last - __first));
188 }
189
190#ifdef _GLIBCXX_USE_CHAR8_T
191
192 // Convert wide character string to narrow.
193 template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
194 inline bool
195 __str_codecvt_out(const _CharT* __first, const _CharT* __last,
196 basic_string<char8_t, _Traits, _Alloc>& __outstr,
197 const codecvt<_CharT, char8_t, _State>& __cvt,
198 _State& __state, size_t& __count)
199 {
200 using _Codecvt = codecvt<_CharT, char8_t, _State>;
201 using _ConvFn
202 = codecvt_base::result
203 (_Codecvt::*)(_State&, const _CharT*, const _CharT*, const _CharT*&,
204 char8_t*, char8_t*, char8_t*&) const;
205 _ConvFn __fn = &codecvt<_CharT, char8_t, _State>::out;
206 return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
207 __count, __fn);
208 }
209
210 template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
211 inline bool
212 __str_codecvt_out(const _CharT* __first, const _CharT* __last,
213 basic_string<char8_t, _Traits, _Alloc>& __outstr,
214 const codecvt<_CharT, char8_t, _State>& __cvt)
215 {
216 _State __state = {};
217 size_t __n;
218 return __str_codecvt_out(__first, __last, __outstr, __cvt, __state, __n);
219 }
220
221#endif // _GLIBCXX_USE_CHAR8_T
222
223 namespace __detail
224 {
225 template<typename _Tp>
226 struct _Scoped_ptr
227 {
228 __attribute__((__nonnull__(2)))
229 explicit
230 _Scoped_ptr(_Tp* __ptr) noexcept
231 : _M_ptr(__ptr)
232 { }
233
234 _Scoped_ptr(_Tp* __ptr, const char* __msg)
235 : _M_ptr(__ptr)
236 {
237 if (!__ptr)
238 __throw_logic_error(__msg);
239 }
240
241 ~_Scoped_ptr() { delete _M_ptr; }
242
243 _Scoped_ptr(const _Scoped_ptr&) = delete;
244 _Scoped_ptr& operator=(const _Scoped_ptr&) = delete;
245
246 __attribute__((__returns_nonnull__))
247 _Tp* operator->() const noexcept { return _M_ptr; }
248
249 _Tp& operator*() const noexcept { return *_M_ptr; }
250
251 private:
252 _Tp* _M_ptr;
253 };
254 }
255
256_GLIBCXX_BEGIN_NAMESPACE_CXX11
257
258 /// String conversions
259 template<typename _Codecvt, typename _Elem = wchar_t,
260 typename _Wide_alloc = allocator<_Elem>,
261 typename _Byte_alloc = allocator<char>>
262 class wstring_convert
263 {
264 public:
265 typedef basic_string<char, char_traits<char>, _Byte_alloc> byte_string;
266 typedef basic_string<_Elem, char_traits<_Elem>, _Wide_alloc> wide_string;
267 typedef typename _Codecvt::state_type state_type;
268 typedef typename wide_string::traits_type::int_type int_type;
269
270 /// Default constructor.
271 wstring_convert() : _M_cvt(new _Codecvt()) { }
272
273 /** Constructor.
274 *
275 * @param __pcvt The facet to use for conversions.
276 *
277 * Takes ownership of @p __pcvt and will delete it in the destructor.
278 */
279 explicit
280 wstring_convert(_Codecvt* __pcvt) : _M_cvt(__pcvt, "wstring_convert")
281 { }
282
283 /** Construct with an initial converstion state.
284 *
285 * @param __pcvt The facet to use for conversions.
286 * @param __state Initial conversion state.
287 *
288 * Takes ownership of @p __pcvt and will delete it in the destructor.
289 * The object's conversion state will persist between conversions.
290 */
291 wstring_convert(_Codecvt* __pcvt, state_type __state)
292 : _M_cvt(__pcvt, "wstring_convert"),
293 _M_state(__state), _M_with_cvtstate(true)
294 { }
295
296 /** Construct with error strings.
297 *
298 * @param __byte_err A string to return on failed conversions.
299 * @param __wide_err A wide string to return on failed conversions.
300 */
301 explicit
302 wstring_convert(const byte_string& __byte_err,
303 const wide_string& __wide_err = wide_string())
304 : _M_cvt(new _Codecvt),
305 _M_byte_err_string(__byte_err), _M_wide_err_string(__wide_err),
306 _M_with_strings(true)
307 { }
308
309 ~wstring_convert() = default;
310
311 // _GLIBCXX_RESOLVE_LIB_DEFECTS
312 // 2176. Special members for wstring_convert and wbuffer_convert
313 wstring_convert(const wstring_convert&) = delete;
314 wstring_convert& operator=(const wstring_convert&) = delete;
315
316 /// @{ Convert from bytes.
317 wide_string
318 from_bytes(char __byte)
319 {
320 char __bytes[2] = { __byte };
321 return from_bytes(__bytes, __bytes+1);
322 }
323
324 wide_string
325 from_bytes(const char* __ptr)
326 { return from_bytes(__ptr, __ptr+char_traits<char>::length(s: __ptr)); }
327
328 wide_string
329 from_bytes(const byte_string& __str)
330 {
331 auto __ptr = __str.data();
332 return from_bytes(__ptr, __ptr + __str.size());
333 }
334
335 wide_string
336 from_bytes(const char* __first, const char* __last)
337 {
338 if (!_M_with_cvtstate)
339 _M_state = state_type();
340 wide_string __out{ _M_wide_err_string.get_allocator() };
341 if (__str_codecvt_in(__first, __last, __out, *_M_cvt, _M_state,
342 _M_count))
343 return __out;
344 if (_M_with_strings)
345 return _M_wide_err_string;
346 __throw_range_error("wstring_convert::from_bytes");
347 }
348 /// @}
349
350 /// @{ Convert to bytes.
351 byte_string
352 to_bytes(_Elem __wchar)
353 {
354 _Elem __wchars[2] = { __wchar };
355 return to_bytes(__wchars, __wchars+1);
356 }
357
358 byte_string
359 to_bytes(const _Elem* __ptr)
360 {
361 return to_bytes(__ptr, __ptr+wide_string::traits_type::length(__ptr));
362 }
363
364 byte_string
365 to_bytes(const wide_string& __wstr)
366 {
367 auto __ptr = __wstr.data();
368 return to_bytes(__ptr, __ptr + __wstr.size());
369 }
370
371 byte_string
372 to_bytes(const _Elem* __first, const _Elem* __last)
373 {
374 if (!_M_with_cvtstate)
375 _M_state = state_type();
376 byte_string __out{ _M_byte_err_string.get_allocator() };
377 if (__str_codecvt_out(__first, __last, __out, *_M_cvt, _M_state,
378 _M_count))
379 return __out;
380 if (_M_with_strings)
381 return _M_byte_err_string;
382 __throw_range_error("wstring_convert::to_bytes");
383 }
384 /// @}
385
386 // _GLIBCXX_RESOLVE_LIB_DEFECTS
387 // 2174. wstring_convert::converted() should be noexcept
388 /// The number of elements successfully converted in the last conversion.
389 size_t converted() const noexcept { return _M_count; }
390
391 /// The final conversion state of the last conversion.
392 state_type state() const { return _M_state; }
393
394 private:
395 __detail::_Scoped_ptr<_Codecvt> _M_cvt;
396 byte_string _M_byte_err_string;
397 wide_string _M_wide_err_string;
398 state_type _M_state = state_type();
399 size_t _M_count = 0;
400 bool _M_with_cvtstate = false;
401 bool _M_with_strings = false;
402 };
403
404_GLIBCXX_END_NAMESPACE_CXX11
405
406 /// Buffer conversions
407 template<typename _Codecvt, typename _Elem = wchar_t,
408 typename _Tr = char_traits<_Elem>>
409 class wbuffer_convert : public basic_streambuf<_Elem, _Tr>
410 {
411 typedef basic_streambuf<_Elem, _Tr> _Wide_streambuf;
412
413 public:
414 typedef typename _Codecvt::state_type state_type;
415
416 /// Default constructor.
417 wbuffer_convert() : wbuffer_convert(nullptr) { }
418
419 /** Constructor.
420 *
421 * @param __bytebuf The underlying byte stream buffer.
422 * @param __pcvt The facet to use for conversions.
423 * @param __state Initial conversion state.
424 *
425 * Takes ownership of @p __pcvt and will delete it in the destructor.
426 */
427 explicit
428 wbuffer_convert(streambuf* __bytebuf, _Codecvt* __pcvt = new _Codecvt,
429 state_type __state = state_type())
430 : _M_buf(__bytebuf), _M_cvt(__pcvt, "wbuffer_convert"),
431 _M_state(__state), _M_always_noconv(_M_cvt->always_noconv())
432 {
433 if (_M_buf)
434 {
435 this->setp(_M_put_area, _M_put_area + _S_buffer_length);
436 this->setg(_M_get_area + _S_putback_length,
437 _M_get_area + _S_putback_length,
438 _M_get_area + _S_putback_length);
439 }
440 }
441
442 ~wbuffer_convert() = default;
443
444 // _GLIBCXX_RESOLVE_LIB_DEFECTS
445 // 2176. Special members for wstring_convert and wbuffer_convert
446 wbuffer_convert(const wbuffer_convert&) = delete;
447 wbuffer_convert& operator=(const wbuffer_convert&) = delete;
448
449 streambuf* rdbuf() const noexcept { return _M_buf; }
450
451 streambuf*
452 rdbuf(streambuf *__bytebuf) noexcept
453 {
454 auto __prev = _M_buf;
455 _M_buf = __bytebuf;
456 return __prev;
457 }
458
459 /// The conversion state following the last conversion.
460 state_type state() const noexcept { return _M_state; }
461
462 protected:
463 int
464 sync()
465 { return _M_buf && _M_conv_put() && !_M_buf->pubsync() ? 0 : -1; }
466
467 typename _Wide_streambuf::int_type
468 overflow(typename _Wide_streambuf::int_type __out)
469 {
470 if (!_M_buf || !_M_conv_put())
471 return _Tr::eof();
472 else if (!_Tr::eq_int_type(__out, _Tr::eof()))
473 return this->sputc(__out);
474 return _Tr::not_eof(__out);
475 }
476
477 typename _Wide_streambuf::int_type
478 underflow()
479 {
480 if (!_M_buf)
481 return _Tr::eof();
482
483 if (this->gptr() < this->egptr() || (_M_buf && _M_conv_get()))
484 return _Tr::to_int_type(*this->gptr());
485 else
486 return _Tr::eof();
487 }
488
489 streamsize
490 xsputn(const typename _Wide_streambuf::char_type* __s, streamsize __n)
491 {
492 if (!_M_buf || __n == 0)
493 return 0;
494 streamsize __done = 0;
495 do
496 {
497 auto __nn = std::min<streamsize>(this->epptr() - this->pptr(),
498 __n - __done);
499 _Tr::copy(this->pptr(), __s + __done, __nn);
500 this->pbump(__nn);
501 __done += __nn;
502 } while (__done < __n && _M_conv_put());
503 return __done;
504 }
505
506 private:
507 // fill the get area from converted contents of the byte stream buffer
508 bool
509 _M_conv_get()
510 {
511 const streamsize __pb1 = this->gptr() - this->eback();
512 const streamsize __pb2 = _S_putback_length;
513 const streamsize __npb = std::min(a: __pb1, b: __pb2);
514
515 _Tr::move(_M_get_area + _S_putback_length - __npb,
516 this->gptr() - __npb, __npb);
517
518 streamsize __nbytes = sizeof(_M_get_buf) - _M_unconv;
519 __nbytes = std::min(a: __nbytes, b: _M_buf->in_avail());
520 if (__nbytes < 1)
521 __nbytes = 1;
522 __nbytes = _M_buf->sgetn(s: _M_get_buf + _M_unconv, n: __nbytes);
523 if (__nbytes < 1)
524 return false;
525 __nbytes += _M_unconv;
526
527 // convert _M_get_buf into _M_get_area
528
529 _Elem* __outbuf = _M_get_area + _S_putback_length;
530 _Elem* __outnext = __outbuf;
531 const char* __bnext = _M_get_buf;
532
533 codecvt_base::result __result;
534 if (_M_always_noconv)
535 __result = codecvt_base::noconv;
536 else
537 {
538 _Elem* __outend = _M_get_area + _S_buffer_length;
539
540 __result = _M_cvt->in(_M_state,
541 __bnext, __bnext + __nbytes, __bnext,
542 __outbuf, __outend, __outnext);
543 }
544
545 if (__result == codecvt_base::noconv)
546 {
547 // cast is safe because noconv means _Elem is same type as char
548 auto __get_buf = reinterpret_cast<const _Elem*>(_M_get_buf);
549 _Tr::copy(__outbuf, __get_buf, __nbytes);
550 _M_unconv = 0;
551 return true;
552 }
553
554 if ((_M_unconv = _M_get_buf + __nbytes - __bnext))
555 char_traits<char>::move(s1: _M_get_buf, s2: __bnext, n: _M_unconv);
556
557 this->setg(__outbuf, __outbuf, __outnext);
558
559 return __result != codecvt_base::error;
560 }
561
562 // unused
563 bool
564 _M_put(...)
565 { return false; }
566
567 bool
568 _M_put(const char* __p, streamsize __n)
569 {
570 if (_M_buf->sputn(s: __p, __n) < __n)
571 return false;
572 return true;
573 }
574
575 // convert the put area and write to the byte stream buffer
576 bool
577 _M_conv_put()
578 {
579 _Elem* const __first = this->pbase();
580 const _Elem* const __last = this->pptr();
581 const streamsize __pending = __last - __first;
582
583 if (_M_always_noconv)
584 return _M_put(__first, __pending);
585
586 char __outbuf[2 * _S_buffer_length];
587
588 const _Elem* __next = __first;
589 const _Elem* __start;
590 do
591 {
592 __start = __next;
593 char* __outnext = __outbuf;
594 char* const __outlast = __outbuf + sizeof(__outbuf);
595 auto __result = _M_cvt->out(_M_state, __next, __last, __next,
596 __outnext, __outlast, __outnext);
597 if (__result == codecvt_base::error)
598 return false;
599 else if (__result == codecvt_base::noconv)
600 return _M_put(__next, __pending);
601
602 if (!_M_put(__outbuf, __outnext - __outbuf))
603 return false;
604 }
605 while (__next != __last && __next != __start);
606
607 if (__next != __last)
608 _Tr::move(__first, __next, __last - __next);
609
610 this->pbump(__first - __next);
611 return __next != __first;
612 }
613
614 streambuf* _M_buf;
615 __detail::_Scoped_ptr<_Codecvt> _M_cvt;
616 state_type _M_state;
617
618 static const streamsize _S_buffer_length = 32;
619 static const streamsize _S_putback_length = 3;
620 _Elem _M_put_area[_S_buffer_length];
621 _Elem _M_get_area[_S_buffer_length];
622 streamsize _M_unconv = 0;
623 char _M_get_buf[_S_buffer_length-_S_putback_length];
624 bool _M_always_noconv;
625 };
626
627 /// @} group locales
628
629_GLIBCXX_END_NAMESPACE_VERSION
630} // namespace
631
632#endif // __cplusplus
633
634#endif /* _LOCALE_CONV_H */
635