1 /* Test for initial conversion state.
2 Copyright (C) 2008-2012 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2008.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17
18 #include <config.h>
19
20 /* Specification. */
21 #include <wchar.h>
22
23 #include "verify.h"
24
25 #if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__
26
27 /* On native Windows, 'mbstate_t' is defined as 'int'. */
28
29 int
mbsinit(const mbstate_t * ps)30 mbsinit (const mbstate_t *ps)
31 {
32 return ps == NULL || *ps == 0;
33 }
34
35 #else
36
37 /* Platforms that lack mbsinit() also lack mbrlen(), mbrtowc(), mbsrtowcs()
38 and wcrtomb(), wcsrtombs().
39 We assume that
40 - sizeof (mbstate_t) >= 4,
41 - only stateless encodings are supported (such as UTF-8 and EUC-JP, but
42 not ISO-2022 variants),
43 - for each encoding, the number of bytes for a wide character is <= 4.
44 (This maximum is attained for UTF-8, GB18030, EUC-TW.)
45 We define the meaning of mbstate_t as follows:
46 - In mb -> wc direction, mbstate_t's first byte contains the number of
47 buffered bytes (in the range 0..3), followed by up to 3 buffered bytes.
48 - In wc -> mb direction, mbstate_t contains no information. In other
49 words, it is always in the initial state. */
50
51 verify (sizeof (mbstate_t) >= 4);
52
53 int
mbsinit(const mbstate_t * ps)54 mbsinit (const mbstate_t *ps)
55 {
56 const char *pstate = (const char *)ps;
57
58 return pstate == NULL || pstate[0] == 0;
59 }
60
61 #endif
62