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Diffstat (limited to 'lib/mbsinit.c')
-rw-r--r-- | lib/mbsinit.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/lib/mbsinit.c b/lib/mbsinit.c new file mode 100644 index 0000000..981a894 --- /dev/null +++ b/lib/mbsinit.c @@ -0,0 +1,70 @@ +/* Test for initial conversion state. + Copyright (C) 2008-2020 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2008. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> + +/* Specification. */ +#include <wchar.h> + +#include "verify.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 the initial state. */ + +verify (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 |