1/* Test for initial conversion state.
2   Copyright (C) 2008, 2009 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}
48