summaryrefslogtreecommitdiff
path: root/lib/mbsinit.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/mbsinit.c')
-rw-r--r--lib/mbsinit.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/lib/mbsinit.c b/lib/mbsinit.c
new file mode 100644
index 0000000..7495794
--- /dev/null
+++ b/lib/mbsinit.c
@@ -0,0 +1,47 @@
+/* Test for initial conversion state.
+ Copyright (C) 2008 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 Lesser 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 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 <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+/* Specification. */
+#include <wchar.h>
+
+#include "verify.h"
+
+/* 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.
+ - 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[0] == 0;
+}