streambuf: Adjust doxygen group markup.
[gcc.git] / libstdc++-v3 / include / bits / codecvt.h
1 // Locale support (codecvt) -*- C++ -*-
2
3 // Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
4 // 2009, 2010 Free Software Foundation, Inc.
5 //
6 // This file is part of the GNU ISO C++ Library. This library is free
7 // software; you can redistribute it and/or modify it under the
8 // terms of the GNU General Public License as published by the
9 // Free Software Foundation; either version 3, or (at your option)
10 // any later version.
11
12 // This library is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
16
17 // Under Section 7 of GPL version 3, you are granted additional
18 // permissions described in the GCC Runtime Library Exception, version
19 // 3.1, as published by the Free Software Foundation.
20
21 // You should have received a copy of the GNU General Public License and
22 // a copy of the GCC Runtime Library Exception along with this program;
23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 // <http://www.gnu.org/licenses/>.
25
26 /** @file bits/codecvt.h
27 * This is an internal header file, included by other library headers.
28 * You should not attempt to use it directly.
29 */
30
31 //
32 // ISO C++ 14882: 22.2.1.5 Template class codecvt
33 //
34
35 // Written by Benjamin Kosnik <bkoz@redhat.com>
36
37 #ifndef _CODECVT_H
38 #define _CODECVT_H 1
39
40 #pragma GCC system_header
41
42 _GLIBCXX_BEGIN_NAMESPACE(std)
43
44 /// Empty base class for codecvt facet [22.2.1.5].
45 class codecvt_base
46 {
47 public:
48 enum result
49 {
50 ok,
51 partial,
52 error,
53 noconv
54 };
55 };
56
57 /**
58 * @brief Common base for codecvt functions.
59 *
60 * This template class provides implementations of the public functions
61 * that forward to the protected virtual functions.
62 *
63 * This template also provides abstract stubs for the protected virtual
64 * functions.
65 */
66 template<typename _InternT, typename _ExternT, typename _StateT>
67 class __codecvt_abstract_base
68 : public locale::facet, public codecvt_base
69 {
70 public:
71 // Types:
72 typedef codecvt_base::result result;
73 typedef _InternT intern_type;
74 typedef _ExternT extern_type;
75 typedef _StateT state_type;
76
77 // 22.2.1.5.1 codecvt members
78 /**
79 * @brief Convert from internal to external character set.
80 *
81 * Converts input string of intern_type to output string of
82 * extern_type. This is analogous to wcsrtombs. It does this by
83 * calling codecvt::do_out.
84 *
85 * The source and destination character sets are determined by the
86 * facet's locale, internal and external types.
87 *
88 * The characters in [from,from_end) are converted and written to
89 * [to,to_end). from_next and to_next are set to point to the
90 * character following the last successfully converted character,
91 * respectively. If the result needed no conversion, from_next and
92 * to_next are not affected.
93 *
94 * The @a state argument should be initialized if the input is at the
95 * beginning and carried from a previous call if continuing
96 * conversion. There are no guarantees about how @a state is used.
97 *
98 * The result returned is a member of codecvt_base::result. If
99 * all the input is converted, returns codecvt_base::ok. If no
100 * conversion is necessary, returns codecvt_base::noconv. If
101 * the input ends early or there is insufficient space in the
102 * output, returns codecvt_base::partial. Otherwise the
103 * conversion failed and codecvt_base::error is returned.
104 *
105 * @param state Persistent conversion state data.
106 * @param from Start of input.
107 * @param from_end End of input.
108 * @param from_next Returns start of unconverted data.
109 * @param to Start of output buffer.
110 * @param to_end End of output buffer.
111 * @param to_next Returns start of unused output area.
112 * @return codecvt_base::result.
113 */
114 result
115 out(state_type& __state, const intern_type* __from,
116 const intern_type* __from_end, const intern_type*& __from_next,
117 extern_type* __to, extern_type* __to_end,
118 extern_type*& __to_next) const
119 {
120 return this->do_out(__state, __from, __from_end, __from_next,
121 __to, __to_end, __to_next);
122 }
123
124 /**
125 * @brief Reset conversion state.
126 *
127 * Writes characters to output that would restore @a state to initial
128 * conditions. The idea is that if a partial conversion occurs, then
129 * the converting the characters written by this function would leave
130 * the state in initial conditions, rather than partial conversion
131 * state. It does this by calling codecvt::do_unshift().
132 *
133 * For example, if 4 external characters always converted to 1 internal
134 * character, and input to in() had 6 external characters with state
135 * saved, this function would write two characters to the output and
136 * set the state to initialized conditions.
137 *
138 * The source and destination character sets are determined by the
139 * facet's locale, internal and external types.
140 *
141 * The result returned is a member of codecvt_base::result. If the
142 * state could be reset and data written, returns codecvt_base::ok. If
143 * no conversion is necessary, returns codecvt_base::noconv. If the
144 * output has insufficient space, returns codecvt_base::partial.
145 * Otherwise the reset failed and codecvt_base::error is returned.
146 *
147 * @param state Persistent conversion state data.
148 * @param to Start of output buffer.
149 * @param to_end End of output buffer.
150 * @param to_next Returns start of unused output area.
151 * @return codecvt_base::result.
152 */
153 result
154 unshift(state_type& __state, extern_type* __to, extern_type* __to_end,
155 extern_type*& __to_next) const
156 { return this->do_unshift(__state, __to,__to_end,__to_next); }
157
158 /**
159 * @brief Convert from external to internal character set.
160 *
161 * Converts input string of extern_type to output string of
162 * intern_type. This is analogous to mbsrtowcs. It does this by
163 * calling codecvt::do_in.
164 *
165 * The source and destination character sets are determined by the
166 * facet's locale, internal and external types.
167 *
168 * The characters in [from,from_end) are converted and written to
169 * [to,to_end). from_next and to_next are set to point to the
170 * character following the last successfully converted character,
171 * respectively. If the result needed no conversion, from_next and
172 * to_next are not affected.
173 *
174 * The @a state argument should be initialized if the input is at the
175 * beginning and carried from a previous call if continuing
176 * conversion. There are no guarantees about how @a state is used.
177 *
178 * The result returned is a member of codecvt_base::result. If
179 * all the input is converted, returns codecvt_base::ok. If no
180 * conversion is necessary, returns codecvt_base::noconv. If
181 * the input ends early or there is insufficient space in the
182 * output, returns codecvt_base::partial. Otherwise the
183 * conversion failed and codecvt_base::error is returned.
184 *
185 * @param state Persistent conversion state data.
186 * @param from Start of input.
187 * @param from_end End of input.
188 * @param from_next Returns start of unconverted data.
189 * @param to Start of output buffer.
190 * @param to_end End of output buffer.
191 * @param to_next Returns start of unused output area.
192 * @return codecvt_base::result.
193 */
194 result
195 in(state_type& __state, const extern_type* __from,
196 const extern_type* __from_end, const extern_type*& __from_next,
197 intern_type* __to, intern_type* __to_end,
198 intern_type*& __to_next) const
199 {
200 return this->do_in(__state, __from, __from_end, __from_next,
201 __to, __to_end, __to_next);
202 }
203
204 int
205 encoding() const throw()
206 { return this->do_encoding(); }
207
208 bool
209 always_noconv() const throw()
210 { return this->do_always_noconv(); }
211
212 int
213 length(state_type& __state, const extern_type* __from,
214 const extern_type* __end, size_t __max) const
215 { return this->do_length(__state, __from, __end, __max); }
216
217 int
218 max_length() const throw()
219 { return this->do_max_length(); }
220
221 protected:
222 explicit
223 __codecvt_abstract_base(size_t __refs = 0) : locale::facet(__refs) { }
224
225 virtual
226 ~__codecvt_abstract_base() { }
227
228 /**
229 * @brief Convert from internal to external character set.
230 *
231 * Converts input string of intern_type to output string of
232 * extern_type. This function is a hook for derived classes to change
233 * the value returned. @see out for more information.
234 */
235 virtual result
236 do_out(state_type& __state, const intern_type* __from,
237 const intern_type* __from_end, const intern_type*& __from_next,
238 extern_type* __to, extern_type* __to_end,
239 extern_type*& __to_next) const = 0;
240
241 virtual result
242 do_unshift(state_type& __state, extern_type* __to,
243 extern_type* __to_end, extern_type*& __to_next) const = 0;
244
245 virtual result
246 do_in(state_type& __state, const extern_type* __from,
247 const extern_type* __from_end, const extern_type*& __from_next,
248 intern_type* __to, intern_type* __to_end,
249 intern_type*& __to_next) const = 0;
250
251 virtual int
252 do_encoding() const throw() = 0;
253
254 virtual bool
255 do_always_noconv() const throw() = 0;
256
257 virtual int
258 do_length(state_type&, const extern_type* __from,
259 const extern_type* __end, size_t __max) const = 0;
260
261 virtual int
262 do_max_length() const throw() = 0;
263 };
264
265
266
267 /**
268 * @brief Primary class template codecvt.
269 * @ingroup locales
270 *
271 * NB: Generic, mostly useless implementation.
272 *
273 */
274 template<typename _InternT, typename _ExternT, typename _StateT>
275 class codecvt
276 : public __codecvt_abstract_base<_InternT, _ExternT, _StateT>
277 {
278 public:
279 // Types:
280 typedef codecvt_base::result result;
281 typedef _InternT intern_type;
282 typedef _ExternT extern_type;
283 typedef _StateT state_type;
284
285 protected:
286 __c_locale _M_c_locale_codecvt;
287
288 public:
289 static locale::id id;
290
291 explicit
292 codecvt(size_t __refs = 0)
293 : __codecvt_abstract_base<_InternT, _ExternT, _StateT> (__refs) { }
294
295 explicit
296 codecvt(__c_locale __cloc, size_t __refs = 0);
297
298 protected:
299 virtual
300 ~codecvt() { }
301
302 virtual result
303 do_out(state_type& __state, const intern_type* __from,
304 const intern_type* __from_end, const intern_type*& __from_next,
305 extern_type* __to, extern_type* __to_end,
306 extern_type*& __to_next) const;
307
308 virtual result
309 do_unshift(state_type& __state, extern_type* __to,
310 extern_type* __to_end, extern_type*& __to_next) const;
311
312 virtual result
313 do_in(state_type& __state, const extern_type* __from,
314 const extern_type* __from_end, const extern_type*& __from_next,
315 intern_type* __to, intern_type* __to_end,
316 intern_type*& __to_next) const;
317
318 virtual int
319 do_encoding() const throw();
320
321 virtual bool
322 do_always_noconv() const throw();
323
324 virtual int
325 do_length(state_type&, const extern_type* __from,
326 const extern_type* __end, size_t __max) const;
327
328 virtual int
329 do_max_length() const throw();
330 };
331
332 template<typename _InternT, typename _ExternT, typename _StateT>
333 locale::id codecvt<_InternT, _ExternT, _StateT>::id;
334
335 /// class codecvt<char, char, mbstate_t> specialization.
336 template<>
337 class codecvt<char, char, mbstate_t>
338 : public __codecvt_abstract_base<char, char, mbstate_t>
339 {
340 public:
341 // Types:
342 typedef char intern_type;
343 typedef char extern_type;
344 typedef mbstate_t state_type;
345
346 protected:
347 __c_locale _M_c_locale_codecvt;
348
349 public:
350 static locale::id id;
351
352 explicit
353 codecvt(size_t __refs = 0);
354
355 explicit
356 codecvt(__c_locale __cloc, size_t __refs = 0);
357
358 protected:
359 virtual
360 ~codecvt();
361
362 virtual result
363 do_out(state_type& __state, const intern_type* __from,
364 const intern_type* __from_end, const intern_type*& __from_next,
365 extern_type* __to, extern_type* __to_end,
366 extern_type*& __to_next) const;
367
368 virtual result
369 do_unshift(state_type& __state, extern_type* __to,
370 extern_type* __to_end, extern_type*& __to_next) const;
371
372 virtual result
373 do_in(state_type& __state, const extern_type* __from,
374 const extern_type* __from_end, const extern_type*& __from_next,
375 intern_type* __to, intern_type* __to_end,
376 intern_type*& __to_next) const;
377
378 virtual int
379 do_encoding() const throw();
380
381 virtual bool
382 do_always_noconv() const throw();
383
384 virtual int
385 do_length(state_type&, const extern_type* __from,
386 const extern_type* __end, size_t __max) const;
387
388 virtual int
389 do_max_length() const throw();
390 };
391
392 #ifdef _GLIBCXX_USE_WCHAR_T
393 /// class codecvt<wchar_t, char, mbstate_t> specialization.
394 template<>
395 class codecvt<wchar_t, char, mbstate_t>
396 : public __codecvt_abstract_base<wchar_t, char, mbstate_t>
397 {
398 public:
399 // Types:
400 typedef wchar_t intern_type;
401 typedef char extern_type;
402 typedef mbstate_t state_type;
403
404 protected:
405 __c_locale _M_c_locale_codecvt;
406
407 public:
408 static locale::id id;
409
410 explicit
411 codecvt(size_t __refs = 0);
412
413 explicit
414 codecvt(__c_locale __cloc, size_t __refs = 0);
415
416 protected:
417 virtual
418 ~codecvt();
419
420 virtual result
421 do_out(state_type& __state, const intern_type* __from,
422 const intern_type* __from_end, const intern_type*& __from_next,
423 extern_type* __to, extern_type* __to_end,
424 extern_type*& __to_next) const;
425
426 virtual result
427 do_unshift(state_type& __state,
428 extern_type* __to, extern_type* __to_end,
429 extern_type*& __to_next) const;
430
431 virtual result
432 do_in(state_type& __state,
433 const extern_type* __from, const extern_type* __from_end,
434 const extern_type*& __from_next,
435 intern_type* __to, intern_type* __to_end,
436 intern_type*& __to_next) const;
437
438 virtual
439 int do_encoding() const throw();
440
441 virtual
442 bool do_always_noconv() const throw();
443
444 virtual
445 int do_length(state_type&, const extern_type* __from,
446 const extern_type* __end, size_t __max) const;
447
448 virtual int
449 do_max_length() const throw();
450 };
451 #endif //_GLIBCXX_USE_WCHAR_T
452
453 /// class codecvt_byname [22.2.1.6].
454 template<typename _InternT, typename _ExternT, typename _StateT>
455 class codecvt_byname : public codecvt<_InternT, _ExternT, _StateT>
456 {
457 public:
458 explicit
459 codecvt_byname(const char* __s, size_t __refs = 0)
460 : codecvt<_InternT, _ExternT, _StateT>(__refs)
461 {
462 if (__builtin_strcmp(__s, "C") != 0
463 && __builtin_strcmp(__s, "POSIX") != 0)
464 {
465 this->_S_destroy_c_locale(this->_M_c_locale_codecvt);
466 this->_S_create_c_locale(this->_M_c_locale_codecvt, __s);
467 }
468 }
469
470 protected:
471 virtual
472 ~codecvt_byname() { }
473 };
474
475 // Inhibit implicit instantiations for required instantiations,
476 // which are defined via explicit instantiations elsewhere.
477 // NB: This syntax is a GNU extension.
478 #if _GLIBCXX_EXTERN_TEMPLATE
479 extern template class codecvt_byname<char, char, mbstate_t>;
480
481 extern template
482 const codecvt<char, char, mbstate_t>&
483 use_facet<codecvt<char, char, mbstate_t> >(const locale&);
484
485 extern template
486 bool
487 has_facet<codecvt<char, char, mbstate_t> >(const locale&);
488
489 #ifdef _GLIBCXX_USE_WCHAR_T
490 extern template class codecvt_byname<wchar_t, char, mbstate_t>;
491
492 extern template
493 const codecvt<wchar_t, char, mbstate_t>&
494 use_facet<codecvt<wchar_t, char, mbstate_t> >(const locale&);
495
496 extern template
497 bool
498 has_facet<codecvt<wchar_t, char, mbstate_t> >(const locale&);
499 #endif
500 #endif
501
502 _GLIBCXX_END_NAMESPACE
503
504 #endif // _CODECVT_H