1 /* Compare UTF-16 strings.
2 Copyright (C) 1999, 2002, 2006, 2009-2020 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2002.
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.
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.
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
24 u16_strncmp (const uint16_t *s1
, const uint16_t *s2
, size_t n
)
26 /* Note that the UTF-16 encoding does NOT preserve lexicographic order.
27 Namely, if uc1 is a 16-bit character and [uc2a,uc2b] is a surrogate pair,
28 we must enforce uc1 < [uc2a,uc2b], even if uc1 > uc2a. */
33 if (c1
!= 0 && c1
== c2
)
38 if (c1
< 0xd800 || c1
>= 0xe000)
40 if (!(c2
< 0xd800 || c2
>= 0xe000))
41 /* c2 is a surrogate, but c1 is not. */
46 if (c2
< 0xd800 || c2
>= 0xe000)
47 /* c1 is a surrogate, but c2 is not. */
50 return (int)c1
- (int)c2
;
51 /* > 0 if c1 > c2, < 0 if c1 < c2, = 0 if c1 and c2 are both 0. */