* All affected files: Update postal address of FSF.
[s-roff.git] / src / libs / libgroff / strcasecmp.c
blob6ed6cc282079a092148b97d1ee4e74c5fb941055
1 /* strcasecmp.c -- case insensitive string comparator
2 Copyright (C) 1998, 1999 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
7 any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software Foundation,
16 Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
18 #if HAVE_CONFIG_H
19 # include <config.h>
20 #endif
22 #ifdef LENGTH_LIMIT
23 # define STRXCASECMP_FUNCTION strncasecmp
24 # define STRXCASECMP_DECLARE_N , size_t n
25 # define LENGTH_LIMIT_EXPR(Expr) Expr
26 #else
27 # define STRXCASECMP_FUNCTION strcasecmp
28 # define STRXCASECMP_DECLARE_N /* empty */
29 # define LENGTH_LIMIT_EXPR(Expr) 0
30 #endif
32 #include <stddef.h>
33 #include <ctype.h>
35 #define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
37 /* Compare {{no more than N characters of }}strings S1 and S2,
38 ignoring case, returning less than, equal to or
39 greater than zero if S1 is lexicographically less
40 than, equal to or greater than S2. */
42 int
43 STRXCASECMP_FUNCTION (const char *s1, const char *s2 STRXCASECMP_DECLARE_N)
45 register const unsigned char *p1 = (const unsigned char *) s1;
46 register const unsigned char *p2 = (const unsigned char *) s2;
47 unsigned char c1, c2;
49 if (p1 == p2 || LENGTH_LIMIT_EXPR (n == 0))
50 return 0;
54 c1 = TOLOWER (*p1);
55 c2 = TOLOWER (*p2);
57 if (LENGTH_LIMIT_EXPR (--n == 0) || c1 == '\0')
58 break;
60 ++p1;
61 ++p2;
63 while (c1 == c2);
65 return c1 - c2;