1 | /* c-strcasecmp.c -- case insensitive string comparator in C locale |
2 | Copyright (C) 1998-1999, 2005-2006, 2009-2019 Free Software Foundation, Inc. |
3 | |
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 3, or (at your option) |
7 | any later version. |
8 | |
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. |
13 | |
14 | You should have received a copy of the GNU General Public License |
15 | along with this program; if not, see <https://www.gnu.org/licenses/>. */ |
16 | |
17 | #include <config.h> |
18 | |
19 | /* Specification. */ |
20 | #include "c-strcase.h" |
21 | |
22 | #include <limits.h> |
23 | |
24 | #include "c-ctype.h" |
25 | |
26 | int |
27 | c_strcasecmp (const char *s1, const char *s2) |
28 | { |
29 | register const unsigned char *p1 = (const unsigned char *) s1; |
30 | register const unsigned char *p2 = (const unsigned char *) s2; |
31 | unsigned char c1, c2; |
32 | |
33 | if (p1 == p2) |
34 | return 0; |
35 | |
36 | do |
37 | { |
38 | c1 = c_tolower (*p1); |
39 | c2 = c_tolower (*p2); |
40 | |
41 | if (c1 == '\0') |
42 | break; |
43 | |
44 | ++p1; |
45 | ++p2; |
46 | } |
47 | while (c1 == c2); |
48 | |
49 | if (UCHAR_MAX <= INT_MAX) |
50 | return c1 - c2; |
51 | else |
52 | /* On machines where 'char' and 'int' are types of the same size, the |
53 | difference of two 'unsigned char' values - including the sign bit - |
54 | doesn't fit in an 'int'. */ |
55 | return (c1 > c2 ? 1 : c1 < c2 ? -1 : 0); |
56 | } |
57 | |