1 // Locale support (codecvt) -*- C++ -*-
3 // Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
4 // Free Software Foundation, Inc.
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32 // ISO C++ 14882: 22.2.1.5 Template class codecvt
35 // Written by Benjamin Kosnik <bkoz@redhat.com>
37 /** @file bits/codecvt.h
38 * This is an internal header file, included by other library headers.
39 * You should not attempt to use it directly.
45 #pragma GCC system_header
47 /// @brief Empty base class for codecvt facet [22.2.1.5].
61 * @brief Common base for codecvt functions.
63 * This template class provides implementations of the public functions
64 * that forward to the protected virtual functions.
66 * This template also provides abstract stubs for the protected virtual
69 template<typename _InternT, typename _ExternT, typename _StateT>
70 class __codecvt_abstract_base
71 : public locale::facet, public codecvt_base
75 typedef codecvt_base::result result;
76 typedef _InternT intern_type;
77 typedef _ExternT extern_type;
78 typedef _StateT state_type;
80 // 22.2.1.5.1 codecvt members
82 * @brief Convert from internal to external character set.
84 * Converts input string of intern_type to output string of
85 * extern_type. This is analogous to wcsrtombs. It does this by
86 * calling codecvt::do_out.
88 * The source and destination character sets are determined by the
89 * facet's locale, internal and external types.
91 * The characters in [from,from_end) are converted and written to
92 * [to,to_end). from_next and to_next are set to point to the
93 * character following the last successfully converted character,
94 * respectively. If the result needed no conversion, from_next and
95 * to_next are not affected.
97 * The @a state argument should be intialized if the input is at the
98 * beginning and carried from a previous call if continuing
99 * conversion. There are no guarantees about how @a state is used.
101 * The result returned is a member of codecvt_base::result. If
102 * all the input is converted, returns codecvt_base::ok. If no
103 * conversion is necessary, returns codecvt_base::noconv. If
104 * the input ends early or there is insufficient space in the
105 * output, returns codecvt_base::partial. Otherwise the
106 * conversion failed and codecvt_base::error is returned.
108 * @param state Persistent conversion state data.
109 * @param from Start of input.
110 * @param from_end End of input.
111 * @param from_next Returns start of unconverted data.
112 * @param to Start of output buffer.
113 * @param to_end End of output buffer.
114 * @param to_next Returns start of unused output area.
115 * @return codecvt_base::result.
118 out(state_type& __state, const intern_type* __from,
119 const intern_type* __from_end, const intern_type*& __from_next,
120 extern_type* __to, extern_type* __to_end,
121 extern_type*& __to_next) const
123 return this->do_out(__state, __from, __from_end, __from_next,
124 __to, __to_end, __to_next);
128 * @brief Reset conversion state.
130 * Writes characters to output that would restore @a state to initial
131 * conditions. The idea is that if a partial conversion occurs, then
132 * the converting the characters written by this function would leave
133 * the state in initial conditions, rather than partial conversion
134 * state. It does this by calling codecvt::do_unshift().
136 * For example, if 4 external characters always converted to 1 internal
137 * character, and input to in() had 6 external characters with state
138 * saved, this function would write two characters to the output and
139 * set the state to initialized conditions.
141 * The source and destination character sets are determined by the
142 * facet's locale, internal and external types.
144 * The result returned is a member of codecvt_base::result. If the
145 * state could be reset and data written, returns codecvt_base::ok. If
146 * no conversion is necessary, returns codecvt_base::noconv. If the
147 * output has insufficient space, returns codecvt_base::partial.
148 * Otherwise the reset failed and codecvt_base::error is returned.
150 * @param state Persistent conversion state data.
151 * @param to Start of output buffer.
152 * @param to_end End of output buffer.
153 * @param to_next Returns start of unused output area.
154 * @return codecvt_base::result.
157 unshift(state_type& __state, extern_type* __to, extern_type* __to_end,
158 extern_type*& __to_next) const
159 { return this->do_unshift(__state, __to,__to_end,__to_next); }
162 * @brief Convert from external to internal character set.
164 * Converts input string of extern_type to output string of
165 * intern_type. This is analogous to mbsrtowcs. It does this by
166 * calling codecvt::do_in.
168 * The source and destination character sets are determined by the
169 * facet's locale, internal and external types.
171 * The characters in [from,from_end) are converted and written to
172 * [to,to_end). from_next and to_next are set to point to the
173 * character following the last successfully converted character,
174 * respectively. If the result needed no conversion, from_next and
175 * to_next are not affected.
177 * The @a state argument should be intialized if the input is at the
178 * beginning and carried from a previous call if continuing
179 * conversion. There are no guarantees about how @a state is used.
181 * The result returned is a member of codecvt_base::result. If
182 * all the input is converted, returns codecvt_base::ok. If no
183 * conversion is necessary, returns codecvt_base::noconv. If
184 * the input ends early or there is insufficient space in the
185 * output, returns codecvt_base::partial. Otherwise the
186 * conversion failed and codecvt_base::error is returned.
188 * @param state Persistent conversion state data.
189 * @param from Start of input.
190 * @param from_end End of input.
191 * @param from_next Returns start of unconverted data.
192 * @param to Start of output buffer.
193 * @param to_end End of output buffer.
194 * @param to_next Returns start of unused output area.
195 * @return codecvt_base::result.
198 in(state_type& __state, const extern_type* __from,
199 const extern_type* __from_end, const extern_type*& __from_next,
200 intern_type* __to, intern_type* __to_end,
201 intern_type*& __to_next) const
203 return this->do_in(__state, __from, __from_end, __from_next,
204 __to, __to_end, __to_next);
208 encoding() const throw()
209 { return this->do_encoding(); }
212 always_noconv() const throw()
213 { return this->do_always_noconv(); }
216 length(state_type& __state, const extern_type* __from,
217 const extern_type* __end, size_t __max) const
218 { return this->do_length(__state, __from, __end, __max); }
221 max_length() const throw()
222 { return this->do_max_length(); }
226 __codecvt_abstract_base(size_t __refs = 0) : locale::facet(__refs) { }
229 ~__codecvt_abstract_base() { }
232 * @brief Convert from internal to external character set.
234 * Converts input string of intern_type to output string of
235 * extern_type. This function is a hook for derived classes to change
236 * the value returned. @see out for more information.
239 do_out(state_type& __state, const intern_type* __from,
240 const intern_type* __from_end, const intern_type*& __from_next,
241 extern_type* __to, extern_type* __to_end,
242 extern_type*& __to_next) const = 0;
245 do_unshift(state_type& __state, extern_type* __to,
246 extern_type* __to_end, extern_type*& __to_next) const = 0;
249 do_in(state_type& __state, const extern_type* __from,
250 const extern_type* __from_end, const extern_type*& __from_next,
251 intern_type* __to, intern_type* __to_end,
252 intern_type*& __to_next) const = 0;
255 do_encoding() const throw() = 0;
258 do_always_noconv() const throw() = 0;
261 do_length(state_type&, const extern_type* __from,
262 const extern_type* __end, size_t __max) const = 0;
265 do_max_length() const throw() = 0;
268 /// @brief class codecvt [22.2.1.5].
269 /// NB: Generic, mostly useless implementation.
270 template<typename _InternT, typename _ExternT, typename _StateT>
272 : public __codecvt_abstract_base<_InternT, _ExternT, _StateT>
276 typedef codecvt_base::result result;
277 typedef _InternT intern_type;
278 typedef _ExternT extern_type;
279 typedef _StateT state_type;
282 __c_locale _M_c_locale_codecvt;
285 static locale::id id;
288 codecvt(size_t __refs = 0)
289 : __codecvt_abstract_base<_InternT, _ExternT, _StateT> (__refs) { }
292 codecvt(__c_locale __cloc, size_t __refs = 0);
299 do_out(state_type& __state, const intern_type* __from,
300 const intern_type* __from_end, const intern_type*& __from_next,
301 extern_type* __to, extern_type* __to_end,
302 extern_type*& __to_next) const;
305 do_unshift(state_type& __state, extern_type* __to,
306 extern_type* __to_end, extern_type*& __to_next) const;
309 do_in(state_type& __state, const extern_type* __from,
310 const extern_type* __from_end, const extern_type*& __from_next,
311 intern_type* __to, intern_type* __to_end,
312 intern_type*& __to_next) const;
315 do_encoding() const throw();
318 do_always_noconv() const throw();
321 do_length(state_type&, const extern_type* __from,
322 const extern_type* __end, size_t __max) const;
325 do_max_length() const throw();
328 template<typename _InternT, typename _ExternT, typename _StateT>
329 locale::id codecvt<_InternT, _ExternT, _StateT>::id;
331 /// @brief class codecvt<char, char, mbstate_t> specialization.
333 class codecvt<char, char, mbstate_t>
334 : public __codecvt_abstract_base<char, char, mbstate_t>
338 typedef char intern_type;
339 typedef char extern_type;
340 typedef mbstate_t state_type;
343 __c_locale _M_c_locale_codecvt;
346 static locale::id id;
349 codecvt(size_t __refs = 0);
352 codecvt(__c_locale __cloc, size_t __refs = 0);
359 do_out(state_type& __state, const intern_type* __from,
360 const intern_type* __from_end, const intern_type*& __from_next,
361 extern_type* __to, extern_type* __to_end,
362 extern_type*& __to_next) const;
365 do_unshift(state_type& __state, extern_type* __to,
366 extern_type* __to_end, extern_type*& __to_next) const;
369 do_in(state_type& __state, const extern_type* __from,
370 const extern_type* __from_end, const extern_type*& __from_next,
371 intern_type* __to, intern_type* __to_end,
372 intern_type*& __to_next) const;
375 do_encoding() const throw();
378 do_always_noconv() const throw();
381 do_length(state_type&, const extern_type* __from,
382 const extern_type* __end, size_t __max) const;
385 do_max_length() const throw();
388 #ifdef _GLIBCXX_USE_WCHAR_T
389 /// @brief class codecvt<wchar_t, char, mbstate_t> specialization.
391 class codecvt<wchar_t, char, mbstate_t>
392 : public __codecvt_abstract_base<wchar_t, char, mbstate_t>
396 typedef wchar_t intern_type;
397 typedef char extern_type;
398 typedef mbstate_t state_type;
401 __c_locale _M_c_locale_codecvt;
404 static locale::id id;
407 codecvt(size_t __refs = 0);
410 codecvt(__c_locale __cloc, size_t __refs = 0);
417 do_out(state_type& __state, const intern_type* __from,
418 const intern_type* __from_end, const intern_type*& __from_next,
419 extern_type* __to, extern_type* __to_end,
420 extern_type*& __to_next) const;
423 do_unshift(state_type& __state,
424 extern_type* __to, extern_type* __to_end,
425 extern_type*& __to_next) const;
428 do_in(state_type& __state,
429 const extern_type* __from, const extern_type* __from_end,
430 const extern_type*& __from_next,
431 intern_type* __to, intern_type* __to_end,
432 intern_type*& __to_next) const;
435 int do_encoding() const throw();
438 bool do_always_noconv() const throw();
441 int do_length(state_type&, const extern_type* __from,
442 const extern_type* __end, size_t __max) const;
445 do_max_length() const throw();
447 #endif //_GLIBCXX_USE_WCHAR_T
449 /// @brief class codecvt_byname [22.2.1.6].
450 template<typename _InternT, typename _ExternT, typename _StateT>
451 class codecvt_byname : public codecvt<_InternT, _ExternT, _StateT>
455 codecvt_byname(const char* __s, size_t __refs = 0)
456 : codecvt<_InternT, _ExternT, _StateT>(__refs)
458 if (std::strcmp(__s, "C") != 0 && std::strcmp(__s, "POSIX") != 0)
460 this->_S_destroy_c_locale(this->_M_c_locale_codecvt);
461 this->_S_create_c_locale(this->_M_c_locale_codecvt, __s);
467 ~codecvt_byname() { }