1 files changed, 63 insertions, 0 deletions
diff --git a/lib/unistring/unistr/u16-mbtoucr.c b/lib/unistring/unistr/u16-mbtoucr.c
new file mode 100644
index 0000000..04f96ac
--- /dev/null
+++ b/lib/unistring/unistr/u16-mbtoucr.c
@@ -0,0 +1,63 @@
+/* Look at first character in UTF-16 string, returning an error code.
+   Copyright (C) 1999-2002, 2006-2007, 2009-2021 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2001.
+
+   This program is free software: you can redistribute it and/or
+   modify it under the terms of either:
+
+     * 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.
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at your
+       option) any later version.
+
+   or both in parallel, as here.
+   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 <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include "unistr.h"
+
+int
+u16_mbtoucr (ucs4_t *puc, const uint16_t *s, size_t n)
+{
+  uint16_t c = *s;
+
+  if (c < 0xd800 || c >= 0xe000)
+    {
+      *puc = c;
+      return 1;
+    }
+  if (c < 0xdc00)
+    {
+      if (n >= 2)
+        {
+          if (s[1] >= 0xdc00 && s[1] < 0xe000)
+            {
+              *puc = 0x10000 + ((c - 0xd800) << 10) + (s[1] - 0xdc00);
+              return 2;
+            }
+          /* invalid multibyte character */
+        }
+      else
+        {
+          /* incomplete multibyte character */
+          *puc = 0xfffd;
+          return -2;
+        }
+    }
+  /* invalid multibyte character */
+  *puc = 0xfffd;
+  return -1;
+}