1/* Copyright (C) 1991-2021 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#ifdef HAVE_CONFIG_H
19# include <config.h>
20#endif
21
22#include <ctype.h>
23#include <string.h>
24
25#ifndef _LIBC
26# define __strcasecmp strcasecmp
27# define TOLOWER(Ch) tolower (Ch)
28#else
29# include <locale/localeinfo.h>
30# ifdef USE_IN_EXTENDED_LOCALE_MODEL
31# define __strcasecmp __strcasecmp_l
32# endif
33# define TOLOWER(Ch) __tolower_l ((Ch), loc)
34#endif
35
36#ifdef USE_IN_EXTENDED_LOCALE_MODEL
37# define LOCALE_PARAM , locale_t loc
38#else
39# define LOCALE_PARAM
40#endif
41
42/* Compare S1 and S2, ignoring case, returning less than, equal to or
43 greater than zero if S1 is lexicographically less than,
44 equal to or greater than S2. */
45int
46__strcasecmp (const char *s1, const char *s2 LOCALE_PARAM)
47{
48#if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
49 locale_t loc = _NL_CURRENT_LOCALE;
50#endif
51 const unsigned char *p1 = (const unsigned char *) s1;
52 const unsigned char *p2 = (const unsigned char *) s2;
53 int result;
54
55 if (p1 == p2)
56 return 0;
57
58 while ((result = TOLOWER (*p1) - TOLOWER (*p2++)) == 0)
59 if (*p1++ == '\0')
60 break;
61
62 return result;
63}
64#ifndef __strcasecmp
65libc_hidden_def (__strcasecmp)
66weak_alias (__strcasecmp, strcasecmp)
67#endif
68