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      1 /*	$NetBSD: strncasecmp.c,v 1.3 2018/08/16 12:03:10 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1987, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #if HAVE_NBTOOL_CONFIG_H
     33 #include "nbtool_config.h"
     34 #endif
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)strcasecmp.c	8.1 (Berkeley) 6/4/93";
     40 #else
     41 __RCSID("$NetBSD: strncasecmp.c,v 1.3 2018/08/16 12:03:10 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #if !defined(_KERNEL) && !defined(_STANDALONE)
     46 #include "namespace.h"
     47 #include <assert.h>
     48 #include <ctype.h>
     49 #include <string.h>
     50 #ifdef __weak_alias
     51 __weak_alias(strcasecmp,_strcasecmp)
     52 __weak_alias(strncasecmp,_strncasecmp)
     53 #endif
     54 #else
     55 #include <lib/libkern/libkern.h>
     56 #include <machine/limits.h>
     57 #endif
     58 
     59 int
     60 strncasecmp(const char *s1, const char *s2, size_t n)
     61 {
     62 
     63 	_DIAGASSERT(s1 != NULL);
     64 	_DIAGASSERT(s2 != NULL);
     65 
     66 	if (n != 0) {
     67 		const unsigned char *us1 = (const unsigned char *)s1,
     68 				*us2 = (const unsigned char *)s2;
     69 
     70 		do {
     71 			if (tolower(*us1) != tolower(*us2++))
     72 				return (tolower(*us1) - tolower(*--us2));
     73 			if (*us1++ == '\0')
     74 				break;
     75 		} while (--n != 0);
     76 	}
     77 	return (0);
     78 }
     79