1 /*	$OpenBSD: strcasecmp.c,v 1.6 2005/08/08 08:05:37 espie 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 #include <string.h>
33 
34 typedef unsigned char u_char;
35 
36 /*
37  * This array is designed for mapping upper and lower case letter
38  * together for a case independent comparison.  The mappings are
39  * based upon ascii character sequences.
40  */
41 static const u_char charmap[] = {
42 	'\000', '\001', '\002', '\003', '\004', '\005', '\006', '\007',
43 	'\010', '\011', '\012', '\013', '\014', '\015', '\016', '\017',
44 	'\020', '\021', '\022', '\023', '\024', '\025', '\026', '\027',
45 	'\030', '\031', '\032', '\033', '\034', '\035', '\036', '\037',
46 	'\040', '\041', '\042', '\043', '\044', '\045', '\046', '\047',
47 	'\050', '\051', '\052', '\053', '\054', '\055', '\056', '\057',
48 	'\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067',
49 	'\070', '\071', '\072', '\073', '\074', '\075', '\076', '\077',
50 	'\100', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
51 	'\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
52 	'\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
53 	'\170', '\171', '\172', '\133', '\134', '\135', '\136', '\137',
54 	'\140', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
55 	'\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
56 	'\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
57 	'\170', '\171', '\172', '\173', '\174', '\175', '\176', '\177',
58 	'\200', '\201', '\202', '\203', '\204', '\205', '\206', '\207',
59 	'\210', '\211', '\212', '\213', '\214', '\215', '\216', '\217',
60 	'\220', '\221', '\222', '\223', '\224', '\225', '\226', '\227',
61 	'\230', '\231', '\232', '\233', '\234', '\235', '\236', '\237',
62 	'\240', '\241', '\242', '\243', '\244', '\245', '\246', '\247',
63 	'\250', '\251', '\252', '\253', '\254', '\255', '\256', '\257',
64 	'\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267',
65 	'\270', '\271', '\272', '\273', '\274', '\275', '\276', '\277',
66 	'\300', '\301', '\302', '\303', '\304', '\305', '\306', '\307',
67 	'\310', '\311', '\312', '\313', '\314', '\315', '\316', '\317',
68 	'\320', '\321', '\322', '\323', '\324', '\325', '\326', '\327',
69 	'\330', '\331', '\332', '\333', '\334', '\335', '\336', '\337',
70 	'\340', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
71 	'\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
72 	'\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367',
73 	'\370', '\371', '\372', '\373', '\374', '\375', '\376', '\377',
74 };
75 
76 int
strcasecmp(const char * s1,const char * s2)77 strcasecmp(const char *s1, const char *s2)
78 {
79 	const u_char *cm = charmap;
80 	const u_char *us1 = (const u_char *)s1;
81 	const u_char *us2 = (const u_char *)s2;
82 
83 	while (cm[*us1] == cm[*us2++])
84 		if (*us1++ == '\0')
85 			return (0);
86 	return (cm[*us1] - cm[*--us2]);
87 }
88 
89 int
strncasecmp(const char * s1,const char * s2,size_t n)90 strncasecmp(const char *s1, const char *s2, size_t n)
91 {
92 	if (n != 0) {
93 		const u_char *cm = charmap;
94 		const u_char *us1 = (const u_char *)s1;
95 		const u_char *us2 = (const u_char *)s2;
96 
97 		do {
98 			if (cm[*us1] != cm[*us2++])
99 				return (cm[*us1] - cm[*--us2]);
100 			if (*us1++ == '\0')
101 				break;
102 		} while (--n != 0);
103 	}
104 	return (0);
105 }
106