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1/* Test for initial conversion state.
2 Copyright (C) 2008 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/* Platforms that lack mbsinit() also lack mbrlen(), mbrtowc(), mbsrtowcs()
26 and wcrtomb(), wcsrtombs().
27 We assume that
28 - sizeof (mbstate_t) >= 4,
29 - only stateless encodings are supported (such as UTF-8 and EUC-JP, but
30 not ISO-2022 variants),
31 - for each encoding, the number of bytes for a wide character is <= 4.
32 (This maximum is attained for UTF-8, GB18030, EUC-TW.)
33 We define the meaning of mbstate_t as follows:
34 - In mb -> wc direction, mbstate_t's first byte contains the number of
35 buffered bytes (in the range 0..3), followed by up to 3 buffered bytes.
36 - In wc -> mb direction, mbstate_t contains no information. In other
37 words, it is always in the initial state. */
38
39verify (sizeof (mbstate_t) >= 4);
40
41int
42mbsinit (const mbstate_t *ps)
43{
44 const char *pstate = (const char *)ps;
45
46 return pstate[0] == 0;
47}