1/* Compare at most N characters of two strings without taking care for
2 the case.
3 Copyright (C) 1992-2020 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library 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
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#ifdef HAVE_CONFIG_H
21# include <config.h>
22#endif
23
24#include <string.h>
25#include <ctype.h>
26
27#ifndef weak_alias
28# define __strncasecmp strncasecmp
29# define TOLOWER(Ch) tolower (Ch)
30#else
31# include <locale/localeinfo.h>
32# ifdef USE_IN_EXTENDED_LOCALE_MODEL
33# define __strncasecmp __strncasecmp_l
34# endif
35# define TOLOWER(Ch) __tolower_l ((Ch), loc)
36#endif
37
38#ifdef USE_IN_EXTENDED_LOCALE_MODEL
39# define LOCALE_PARAM , locale_t loc
40#else
41# define LOCALE_PARAM
42#endif
43
44/* Compare no more than N characters of S1 and S2,
45 ignoring case, returning less than, equal to or
46 greater than zero if S1 is lexicographically less
47 than, equal to or greater than S2. */
48int
49__strncasecmp (const char *s1, const char *s2, size_t n LOCALE_PARAM)
50{
51#if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
52 locale_t loc = _NL_CURRENT_LOCALE;
53#endif
54 const unsigned char *p1 = (const unsigned char *) s1;
55 const unsigned char *p2 = (const unsigned char *) s2;
56 int result;
57
58 if (p1 == p2 || n == 0)
59 return 0;
60
61 while ((result = TOLOWER (*p1) - TOLOWER (*p2++)) == 0)
62 if (*p1++ == '\0' || --n == 0)
63 break;
64
65 return result;
66}
67#ifndef __strncasecmp
68weak_alias (__strncasecmp, strncasecmp)
69#endif
70