1/* Look at first character in UTF-16 string, returning an error code.
2   Copyright (C) 1999-2002, 2006-2007, 2009-2010 Free Software Foundation, Inc.
3   Written by Bruno Haible <bruno@clisp.org>, 2001.
4
5   This program is free software: you can redistribute it and/or modify it
6   under the terms of the GNU Lesser General Public License as published
7   by the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17
18#include <config.h>
19
20/* Specification.  */
21#include "unistr.h"
22
23int
24u16_mbtoucr (ucs4_t *puc, const uint16_t *s, size_t n)
25{
26  uint16_t c = *s;
27
28  if (c < 0xd800 || c >= 0xe000)
29    {
30      *puc = c;
31      return 1;
32    }
33  if (c < 0xdc00)
34    {
35      if (n >= 2)
36        {
37          if (s[1] >= 0xdc00 && s[1] < 0xe000)
38            {
39              *puc = 0x10000 + ((c - 0xd800) << 10) + (s[1] - 0xdc00);
40              return 2;
41            }
42          /* invalid multibyte character */
43        }
44      else
45        {
46          /* incomplete multibyte character */
47          *puc = 0xfffd;
48          return -2;
49        }
50    }
51  /* invalid multibyte character */
52  *puc = 0xfffd;
53  return -1;
54}
55