1 // std::codecvt implementation details, GNU version -*- C++ -*-
2
3 // Copyright (C) 2002, 2003, 2005, 2006 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 2, 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 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19 // USA.
20
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
29
30 //
31 // ISO C++ 14882: 22.2.1.5 - Template class codecvt
32 //
33
34 // Written by Benjamin Kosnik <bkoz@redhat.com>
35
36 #include <locale>
37 #include <bits/c++locale_internal.h>
38
_GLIBCXX_BEGIN_NAMESPACE(std)39 _GLIBCXX_BEGIN_NAMESPACE(std)
40
41 // Specializations.
42 #ifdef _GLIBCXX_USE_WCHAR_T
43 codecvt_base::result
44 codecvt<wchar_t, char, mbstate_t>::
45 do_out(state_type& __state, const intern_type* __from,
46 const intern_type* __from_end, const intern_type*& __from_next,
47 extern_type* __to, extern_type* __to_end,
48 extern_type*& __to_next) const
49 {
50 result __ret = ok;
51 state_type __tmp_state(__state);
52
53 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
54 __c_locale __old = __uselocale(_M_c_locale_codecvt);
55 #endif
56
57 // wcsnrtombs is *very* fast but stops if encounters NUL characters:
58 // in case we fall back to wcrtomb and then continue, in a loop.
59 // NB: wcsnrtombs is a GNU extension
60 for (__from_next = __from, __to_next = __to;
61 __from_next < __from_end && __to_next < __to_end
62 && __ret == ok;)
63 {
64 const intern_type* __from_chunk_end = wmemchr(__from_next, L'\0',
65 __from_end - __from_next);
66 if (!__from_chunk_end)
67 __from_chunk_end = __from_end;
68
69 __from = __from_next;
70 const size_t __conv = wcsnrtombs(__to_next, &__from_next,
71 __from_chunk_end - __from_next,
72 __to_end - __to_next, &__state);
73 if (__conv == static_cast<size_t>(-1))
74 {
75 // In case of error, in order to stop at the exact place we
76 // have to start again from the beginning with a series of
77 // wcrtomb.
78 for (; __from < __from_next; ++__from)
79 __to_next += wcrtomb(__to_next, *__from, &__tmp_state);
80 __state = __tmp_state;
81 __ret = error;
82 }
83 else if (__from_next && __from_next < __from_chunk_end)
84 {
85 __to_next += __conv;
86 __ret = partial;
87 }
88 else
89 {
90 __from_next = __from_chunk_end;
91 __to_next += __conv;
92 }
93
94 if (__from_next < __from_end && __ret == ok)
95 {
96 extern_type __buf[MB_LEN_MAX];
97 __tmp_state = __state;
98 const size_t __conv2 = wcrtomb(__buf, *__from_next, &__tmp_state);
99 if (__conv2 > static_cast<size_t>(__to_end - __to_next))
100 __ret = partial;
101 else
102 {
103 memcpy(__to_next, __buf, __conv2);
104 __state = __tmp_state;
105 __to_next += __conv2;
106 ++__from_next;
107 }
108 }
109 }
110
111 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
112 __uselocale(__old);
113 #endif
114
115 return __ret;
116 }
117
118 codecvt_base::result
119 codecvt<wchar_t, char, mbstate_t>::
do_in(state_type & __state,const extern_type * __from,const extern_type * __from_end,const extern_type * & __from_next,intern_type * __to,intern_type * __to_end,intern_type * & __to_next) const120 do_in(state_type& __state, const extern_type* __from,
121 const extern_type* __from_end, const extern_type*& __from_next,
122 intern_type* __to, intern_type* __to_end,
123 intern_type*& __to_next) const
124 {
125 result __ret = ok;
126 state_type __tmp_state(__state);
127
128 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
129 __c_locale __old = __uselocale(_M_c_locale_codecvt);
130 #endif
131
132 // mbsnrtowcs is *very* fast but stops if encounters NUL characters:
133 // in case we store a L'\0' and then continue, in a loop.
134 // NB: mbsnrtowcs is a GNU extension
135 for (__from_next = __from, __to_next = __to;
136 __from_next < __from_end && __to_next < __to_end
137 && __ret == ok;)
138 {
139 const extern_type* __from_chunk_end;
140 __from_chunk_end = static_cast<const extern_type*>(memchr(__from_next, '\0',
141 __from_end
142 - __from_next));
143 if (!__from_chunk_end)
144 __from_chunk_end = __from_end;
145
146 __from = __from_next;
147 size_t __conv = mbsnrtowcs(__to_next, &__from_next,
148 __from_chunk_end - __from_next,
149 __to_end - __to_next, &__state);
150 if (__conv == static_cast<size_t>(-1))
151 {
152 // In case of error, in order to stop at the exact place we
153 // have to start again from the beginning with a series of
154 // mbrtowc.
155 for (;; ++__to_next, __from += __conv)
156 {
157 __conv = mbrtowc(__to_next, __from, __from_end - __from,
158 &__tmp_state);
159 if (__conv == static_cast<size_t>(-1)
160 || __conv == static_cast<size_t>(-2))
161 break;
162 }
163 __from_next = __from;
164 __state = __tmp_state;
165 __ret = error;
166 }
167 else if (__from_next && __from_next < __from_chunk_end)
168 {
169 // It is unclear what to return in this case (see DR 382).
170 __to_next += __conv;
171 __ret = partial;
172 }
173 else
174 {
175 __from_next = __from_chunk_end;
176 __to_next += __conv;
177 }
178
179 if (__from_next < __from_end && __ret == ok)
180 {
181 if (__to_next < __to_end)
182 {
183 // XXX Probably wrong for stateful encodings
184 __tmp_state = __state;
185 ++__from_next;
186 *__to_next++ = L'\0';
187 }
188 else
189 __ret = partial;
190 }
191 }
192
193 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
194 __uselocale(__old);
195 #endif
196
197 return __ret;
198 }
199
200 int
201 codecvt<wchar_t, char, mbstate_t>::
do_encoding() const202 do_encoding() const throw()
203 {
204 // XXX This implementation assumes that the encoding is
205 // stateless and is either single-byte or variable-width.
206 int __ret = 0;
207 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
208 __c_locale __old = __uselocale(_M_c_locale_codecvt);
209 #endif
210 if (MB_CUR_MAX == 1)
211 __ret = 1;
212 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
213 __uselocale(__old);
214 #endif
215 return __ret;
216 }
217
218 int
219 codecvt<wchar_t, char, mbstate_t>::
do_max_length() const220 do_max_length() const throw()
221 {
222 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
223 __c_locale __old = __uselocale(_M_c_locale_codecvt);
224 #endif
225 // XXX Probably wrong for stateful encodings.
226 int __ret = MB_CUR_MAX;
227 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
228 __uselocale(__old);
229 #endif
230 return __ret;
231 }
232
233 int
234 codecvt<wchar_t, char, mbstate_t>::
do_length(state_type & __state,const extern_type * __from,const extern_type * __end,size_t __max) const235 do_length(state_type& __state, const extern_type* __from,
236 const extern_type* __end, size_t __max) const
237 {
238 int __ret = 0;
239 state_type __tmp_state(__state);
240
241 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
242 __c_locale __old = __uselocale(_M_c_locale_codecvt);
243 #endif
244
245 // mbsnrtowcs is *very* fast but stops if encounters NUL characters:
246 // in case we advance past it and then continue, in a loop.
247 // NB: mbsnrtowcs is a GNU extension
248
249 // A dummy internal buffer is needed in order for mbsnrtocws to consider
250 // its fourth parameter (it wouldn't with NULL as first parameter).
251 wchar_t* __to = static_cast<wchar_t*>(__builtin_alloca(sizeof(wchar_t)
252 * __max));
253 while (__from < __end && __max)
254 {
255 const extern_type* __from_chunk_end;
256 __from_chunk_end = static_cast<const extern_type*>(memchr(__from, '\0',
257 __end
258 - __from));
259 if (!__from_chunk_end)
260 __from_chunk_end = __end;
261
262 const extern_type* __tmp_from = __from;
263 size_t __conv = mbsnrtowcs(__to, &__from,
264 __from_chunk_end - __from,
265 __max, &__state);
266 if (__conv == static_cast<size_t>(-1))
267 {
268 // In case of error, in order to stop at the exact place we
269 // have to start again from the beginning with a series of
270 // mbrtowc.
271 for (__from = __tmp_from;; __from += __conv)
272 {
273 __conv = mbrtowc(NULL, __from, __end - __from,
274 &__tmp_state);
275 if (__conv == static_cast<size_t>(-1)
276 || __conv == static_cast<size_t>(-2))
277 break;
278 }
279 __state = __tmp_state;
280 __ret += __from - __tmp_from;
281 break;
282 }
283 if (!__from)
284 __from = __from_chunk_end;
285
286 __ret += __from - __tmp_from;
287 __max -= __conv;
288
289 if (__from < __end && __max)
290 {
291 // XXX Probably wrong for stateful encodings
292 __tmp_state = __state;
293 ++__from;
294 ++__ret;
295 --__max;
296 }
297 }
298
299 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
300 __uselocale(__old);
301 #endif
302
303 return __ret;
304 }
305 #endif
306
307 _GLIBCXX_END_NAMESPACE
308