1 // std::codecvt implementation details, generic version -*- C++ -*-
3 // Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2009
4 // Free Software Foundation, Inc.
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)
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.
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.
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/>.
27 // ISO C++ 14882: 22.2.1.5 - Template class codecvt
30 // Written by Benjamin Kosnik <bkoz@redhat.com>
33 #include <cstdlib> // For MB_CUR_MAX
34 #include <climits> // For MB_LEN_MAX
37 _GLIBCXX_BEGIN_NAMESPACE(std)
40 #ifdef _GLIBCXX_USE_WCHAR_T
42 codecvt<wchar_t, char, mbstate_t>::
43 do_out(state_type& __state, const intern_type* __from,
44 const intern_type* __from_end, const intern_type*& __from_next,
45 extern_type* __to, extern_type* __to_end,
46 extern_type*& __to_next) const
49 // The conversion must be done using a temporary destination buffer
50 // since it is not possible to pass the size of the buffer to wcrtomb
51 state_type __tmp_state(__state);
53 // The conversion must be done by calling wcrtomb in a loop rather
54 // than using wcsrtombs because wcsrtombs assumes that the input is
57 // Either we can upper bound the total number of external characters to
58 // something smaller than __to_end - __to or the conversion must be done
59 // using a temporary destination buffer since it is not possible to
60 // pass the size of the buffer to wcrtomb
61 if (MB_CUR_MAX * (__from_end - __from) - (__to_end - __to) <= 0)
62 while (__from < __from_end)
64 const size_t __conv = wcrtomb(__to, *__from, &__tmp_state);
65 if (__conv == static_cast<size_t>(-1))
70 __state = __tmp_state;
76 extern_type __buf[MB_LEN_MAX];
77 while (__from < __from_end && __to < __to_end)
79 const size_t __conv = wcrtomb(__buf, *__from, &__tmp_state);
80 if (__conv == static_cast<size_t>(-1))
85 else if (__conv > static_cast<size_t>(__to_end - __to))
91 memcpy(__to, __buf, __conv);
92 __state = __tmp_state;
98 if (__ret == ok && __from < __from_end)
101 __from_next = __from;
107 codecvt<wchar_t, char, mbstate_t>::
108 do_in(state_type& __state, const extern_type* __from,
109 const extern_type* __from_end, const extern_type*& __from_next,
110 intern_type* __to, intern_type* __to_end,
111 intern_type*& __to_next) const
114 // This temporary state object is neccessary so __state won't be modified
115 // if [__from, __from_end) is a partial multibyte character.
116 state_type __tmp_state(__state);
118 // Conversion must be done by calling mbrtowc in a loop rather than
119 // by calling mbsrtowcs because mbsrtowcs assumes that the input
120 // sequence is zero-terminated.
121 while (__from < __from_end && __to < __to_end)
123 size_t __conv = mbrtowc(__to, __from, __from_end - __from,
125 if (__conv == static_cast<size_t>(-1))
130 else if (__conv == static_cast<size_t>(-2))
132 // It is unclear what to return in this case (see DR 382).
136 else if (__conv == 0)
138 // XXX Probably wrong for stateful encodings
143 __state = __tmp_state;
148 // It is not clear that __from < __from_end implies __ret != ok
150 if (__ret == ok && __from < __from_end)
153 __from_next = __from;
159 codecvt<wchar_t, char, mbstate_t>::
160 do_encoding() const throw()
162 // XXX This implementation assumes that the encoding is
163 // stateless and is either single-byte or variable-width.
171 codecvt<wchar_t, char, mbstate_t>::
172 do_max_length() const throw()
174 // XXX Probably wrong for stateful encodings.
175 int __ret = MB_CUR_MAX;
180 codecvt<wchar_t, char, mbstate_t>::
181 do_length(state_type& __state, const extern_type* __from,
182 const extern_type* __end, size_t __max) const
185 state_type __tmp_state(__state);
187 while (__from < __end && __max)
189 size_t __conv = mbrtowc(NULL, __from, __end - __from, &__tmp_state);
190 if (__conv == static_cast<size_t>(-1))
192 // Invalid source character
195 else if (__conv == static_cast<size_t>(-2))
197 // Remainder of input does not form a complete destination
201 else if (__conv == 0)
203 // XXX Probably wrong for stateful encodings
207 __state = __tmp_state;
217 _GLIBCXX_END_NAMESPACE