xref: /csrg-svn/lib/libc/string/strcasecmp.c (revision 31747)
1 /*
2  * Copyright (c) 1987 Regents of the University of California.
3  * All rights reserved.  The Berkeley software License Agreement
4  * specifies the terms and conditions for redistribution.
5  */
6 
7 #if defined(LIBC_SCCS) && !defined(lint)
8 static char sccsid[] = "@(#)strcasecmp.c	5.2 (Berkeley) 07/02/87";
9 #endif LIBC_SCCS and not lint
10 
11 /*
12  * This array is designed for mapping upper and lower case letter
13  * together for a case independent comparison.  The mappings are
14  * based upon ascii character sequences.
15  */
16 static char charmap[] = {
17 	'\000', '\001', '\002', '\003', '\004', '\005', '\006', '\007',
18 	'\010', '\011', '\012', '\013', '\014', '\015', '\016', '\017',
19 	'\020', '\021', '\022', '\023', '\024', '\025', '\026', '\027',
20 	'\030', '\031', '\032', '\033', '\034', '\035', '\036', '\037',
21 	'\040', '\041', '\042', '\043', '\044', '\045', '\046', '\047',
22 	'\050', '\051', '\052', '\053', '\054', '\055', '\056', '\057',
23 	'\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067',
24 	'\070', '\071', '\072', '\073', '\074', '\075', '\076', '\077',
25 	'\100', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
26 	'\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
27 	'\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
28 	'\170', '\171', '\172', '\133', '\134', '\135', '\136', '\137',
29 	'\140', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
30 	'\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
31 	'\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
32 	'\170', '\171', '\172', '\173', '\174', '\175', '\176', '\177',
33 	'\200', '\201', '\202', '\203', '\204', '\205', '\206', '\207',
34 	'\210', '\211', '\212', '\213', '\214', '\215', '\216', '\217',
35 	'\220', '\221', '\222', '\223', '\224', '\225', '\226', '\227',
36 	'\230', '\231', '\232', '\233', '\234', '\235', '\236', '\237',
37 	'\240', '\241', '\242', '\243', '\244', '\245', '\246', '\247',
38 	'\250', '\251', '\252', '\253', '\254', '\255', '\256', '\257',
39 	'\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267',
40 	'\270', '\271', '\272', '\273', '\274', '\275', '\276', '\277',
41 	'\300', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
42 	'\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
43 	'\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367',
44 	'\370', '\371', '\372', '\333', '\334', '\335', '\336', '\337',
45 	'\340', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
46 	'\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
47 	'\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367',
48 	'\370', '\371', '\372', '\373', '\374', '\375', '\376', '\377',
49 };
50 
51 strcasecmp(s1, s2)
52 	register char *s1, *s2;
53 {
54 	register char *cm = charmap;
55 
56 	while (cm[*s1] == cm[*s2++])
57 		if (*s1++ == '\0')
58 			return(0);
59 	return(cm[*s1] - cm[*--s2]);
60 }
61 
62 strcasencmp(s1, s2, n)
63 	register char *s1, *s2;
64 	register int n;
65 {
66 	register char *cm = charmap;
67 
68 	while (--n >= 0 && cm[*s1] == cm[*s2++])
69 		if (*s1++ == '\0')
70 			return(0);
71 	return(n < 0 ? 0 : cm[*s1] - cm[*--s2]);
72 }
73