-#if HAVE_CONFIG_H
-# include <config.h>
-#endif
+/* strncasecmp.c -- case insensitive string comparator
+ Copyright (C) 1998-1999, 2005-2007 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#include <config.h>
+
+/* Specification. */
+#include <string.h>
-#include <sys/types.h>
#include <ctype.h>
+#include <limits.h>
#define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
-/* 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. */
+/* Compare no more than N bytes of strings 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.
+ Note: This function cannot work correctly in multibyte locales. */
int
strncasecmp (const char *s1, const char *s2, size_t n)
do
{
- c1 = TOLOWER (*p1++);
- c2 = TOLOWER (*p2++);
- if (c1 == '\0' || c1 != c2)
- return c1 - c2;
- } while (--n > 0);
+ c1 = TOLOWER (*p1);
+ c2 = TOLOWER (*p2);
+
+ if (--n == 0 || c1 == '\0')
+ break;
+
+ ++p1;
+ ++p2;
+ }
+ while (c1 == c2);
- return c1 - c2;
+ if (UCHAR_MAX <= INT_MAX)
+ return c1 - c2;
+ else
+ /* On machines where 'char' and 'int' are types of the same size, the
+ difference of two 'unsigned char' values - including the sign bit -
+ doesn't fit in an 'int'. */
+ return (c1 > c2 ? 1 : c1 < c2 ? -1 : 0);
}