1 files changed, 51 insertions, 0 deletions
diff --git a/lib/unistr/u16-check.c b/lib/unistr/u16-check.c
new file mode 100644
index 00000000..380cec2c
--- /dev/null
+++ b/lib/unistr/u16-check.c
@@ -0,0 +1,51 @@
+/* Check UTF-16 string.
+   Copyright (C) 2002, 2006-2007 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2002.
+
+   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 "unistr.h"
+
+const uint16_t *
+u16_check (const uint16_t *s, size_t n)
+{
+  const uint16_t *s_end = s + n;
+
+  while (s < s_end)
+    {
+      /* Keep in sync with unistr.h and utf16-ucs4.c.  */
+      uint16_t c = *s;
+
+      if (c < 0xd800 || c >= 0xe000)
+	{
+	  s++;
+	  continue;
+	}
+      if (c < 0xdc00)
+	{
+	  if (s + 2 <= s_end
+	      && s[1] >= 0xdc00 && s[1] < 0xe000)
+	    {
+	      s += 2;
+	      continue;
+	    }
+	}
+      /* invalid or incomplete multibyte character */
+      return s;
+    }
+  return NULL;
+}