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/* Test for initial conversion state.
Copyright (C) 2008-2023 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2008.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include <wchar.h>
#if GNULIB_defined_mbstate_t
/* Platforms that lack mbsinit() also lack mbrlen(), mbrtowc(), mbsrtowcs()
and wcrtomb(), wcsrtombs().
We assume that
- sizeof (mbstate_t) >= 4,
- only stateless encodings are supported (such as UTF-8 and EUC-JP, but
not ISO-2022 variants),
- for each encoding, the number of bytes for a wide character is <= 4.
(This maximum is attained for UTF-8, GB18030, EUC-TW.)
We define the meaning of mbstate_t as follows:
- In mb -> wc direction, mbstate_t's first byte contains the number of
buffered bytes (in the range 0..3), followed by up to 3 buffered bytes.
See mbrtowc.c.
- In wc -> mb direction, mbstate_t contains no information. In other
words, it is always in an initial state. */
static_assert (sizeof (mbstate_t) >= 4);
int
mbsinit (const mbstate_t *ps)
{
const char *pstate = (const char *)ps;
return pstate == NULL || pstate[0] == 0;
}
#else
int
mbsinit (const mbstate_t *ps)
{
# if defined _WIN32 && !defined __CYGWIN__
/* Native Windows. */
/* MSVC defines 'mbstate_t' as an 8-byte struct; the first 4 bytes matter.
On mingw, 'mbstate_t' is sometimes defined as 'int', sometimes defined as
an 8-byte struct, of which the first 4 bytes matter. */
return ps == NULL || *(const unsigned int *)ps == 0;
# else
/* Minix, HP-UX 11.00, Solaris 2.6, Interix, ... */
/* Maybe this definition works, maybe not... */
return ps == NULL || *(const char *)ps == 0;
# endif
}
#endif
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