glibc/string/strncase.c

70 lines
2.0 KiB
C

/* Compare at most N characters of two strings without taking care for
the case.
Copyright (C) 1992-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h>
#include <ctype.h>
#ifndef weak_alias
# define __strncasecmp strncasecmp
# define TOLOWER(Ch) tolower (Ch)
#else
# include <locale/localeinfo.h>
# ifdef USE_IN_EXTENDED_LOCALE_MODEL
# define __strncasecmp __strncasecmp_l
# endif
# define TOLOWER(Ch) __tolower_l ((Ch), loc)
#endif
#ifdef USE_IN_EXTENDED_LOCALE_MODEL
# define LOCALE_PARAM , locale_t loc
#else
# define LOCALE_PARAM
#endif
/* Compare no more than N characters of S1 and S2,
ignoring case, returning less than, equal to or
greater than zero if S1 is lexicographically less
than, equal to or greater than S2. */
int
__strncasecmp (const char *s1, const char *s2, size_t n LOCALE_PARAM)
{
#if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
locale_t loc = _NL_CURRENT_LOCALE;
#endif
const unsigned char *p1 = (const unsigned char *) s1;
const unsigned char *p2 = (const unsigned char *) s2;
int result;
if (p1 == p2 || n == 0)
return 0;
while ((result = TOLOWER (*p1) - TOLOWER (*p2++)) == 0)
if (*p1++ == '\0' || --n == 0)
break;
return result;
}
#ifndef __strncasecmp
weak_alias (__strncasecmp, strncasecmp)
#endif