1 /* Look at first character in UTF-16 string.
2 Copyright (C) 1999-2000, 2002, 2006-2007, 2009-2014 Free Software
3 Foundation, Inc.
4 Written by Bruno Haible <bruno@clisp.org>, 2002.
5
6 This program is free software: you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published
8 by the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18
19 #include <config.h>
20
21 /* Specification. */
22 #include "unistr.h"
23
24 int
u16_mblen(const uint16_t * s,size_t n)25 u16_mblen (const uint16_t *s, size_t n)
26 {
27 if (n > 0)
28 {
29 /* Keep in sync with unistr.h and utf16-ucs4.c. */
30 uint16_t c = *s;
31
32 if (c < 0xd800 || c >= 0xe000)
33 return (c != 0 ? 1 : 0);
34 #if CONFIG_UNICODE_SAFETY
35 if (c < 0xdc00)
36 {
37 if (n >= 2
38 && s[1] >= 0xdc00 && s[1] < 0xe000)
39 return 2;
40 }
41 #else
42 {
43 if (n >= 2)
44 return 2;
45 }
46 #endif
47 }
48 /* invalid or incomplete multibyte character */
49 return -1;
50 }
51