1 /* Look at first character in UTF-16 string.
2 Copyright (C) 1999-2000, 2002, 2006-2007, 2009-2021 Free Software
3 Foundation, Inc.
4 Written by Bruno Haible <bruno@clisp.org>, 2002.
5
6 This file is free software.
7 It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
8 You can redistribute it and/or modify it under either
9 - the terms of the GNU Lesser General Public License as published
10 by the Free Software Foundation; either version 3, or (at your
11 option) any later version, or
12 - the terms of the GNU General Public License as published by the
13 Free Software Foundation; either version 2, or (at your option)
14 any later version, or
15 - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
16
17 This file is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 Lesser General Public License and the GNU General Public License
21 for more details.
22
23 You should have received a copy of the GNU Lesser General Public
24 License and of the GNU General Public License along with this
25 program. If not, see <https://www.gnu.org/licenses/>. */
26
27 #include <config.h>
28
29 /* Specification. */
30 #include "unistr.h"
31
32 int
u16_mblen(const uint16_t * s,size_t n)33 u16_mblen (const uint16_t *s, size_t n)
34 {
35 if (n > 0)
36 {
37 /* Keep in sync with unistr.h and u16-mbtouc-aux.c. */
38 uint16_t c = *s;
39
40 if (c < 0xd800 || c >= 0xe000)
41 return (c != 0 ? 1 : 0);
42 if (c < 0xdc00)
43 {
44 if (n >= 2
45 && s[1] >= 0xdc00 && s[1] < 0xe000)
46 return 2;
47 }
48 }
49 /* invalid or incomplete multibyte character */
50 return -1;
51 }
52