1 /* $OpenBSD: strncasecmp.c,v 1.6 2014/06/10 04:16:57 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
33 #include <lib/libkern/libkern.h>
34
35 int
strncasecmp(const char * s1,const char * s2,size_t n)36 strncasecmp(const char *s1, const char *s2, size_t n)
37 {
38 if (n == 0)
39 return 0;
40
41 do {
42 unsigned char c1 = (unsigned char) *s1++;
43 unsigned char c2 = (unsigned char) *s2++;
44
45 if (c1 != c2) {
46 if (c1 >= 'A' && c1 <= 'Z' &&
47 c2 >= 'a' && c2 <= 'z')
48 c1 += 'a' - 'A';
49 else if (c1 >= 'a' && c1 <= 'z' &&
50 c2 >= 'A' && c2 <= 'Z')
51 c2 += 'a' - 'A';
52 if (c1 != c2)
53 return c1 - c2;
54 }
55 if (c1 == 0)
56 break;
57 } while (--n != 0);
58
59 return 0;
60 }
61