1 /* $OpenBSD: strncasecmp.c,v 1.4 2004/08/07 00:38:33 deraadt Exp $ */
2
3 /*
4 * Copyright (c) 1994 Christian E. Hopps
5 * 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. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by Christian E. Hopps.
18 * 4. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32 #if defined(LIBC_SCCS) && !defined(lint)
33 static char *rcsid = "$Id: strncasecmp.c,v 1.4 2004/08/07 00:38:33 deraadt Exp $";
34 #endif /* LIBC_SCCS and not lint */
35
36 #if !defined(_KERNEL) && !defined(_STANDALONE)
37 #include <string.h>
38 #else
39 #include <lib/libkern/libkern.h>
40 #endif
41
42 int
43 strncasecmp(const char *s1, const char *s2, size_t n)
44 {
45 if (n == 0)
46 return 0;
47
48 do {
49 unsigned char c1 = (unsigned char) *s1++;
50 unsigned char c2 = (unsigned char) *s2++;
51
52 if (c1 != c2) {
53 if (c1 >= 'A' && c1 <= 'Z' &&
54 c2 >= 'a' && c2 <= 'z')
55 c1 += 'a' - 'A';
56 else if (c1 >= 'a' && c1 <= 'z' &&
57 c2 >= 'A' && c2 <= 'Z')
58 c2 += 'a' - 'A';
59 if (c1 != c2)
60 return c1 - c2;
61 }
62 if (c1 == 0)
63 break;
64 } while (--n != 0);
65
66 return 0;
67 }