1 /* Case-insensitive buffer comparator.
2 Copyright (C) 1996-1997, 2000, 2003, 2006, 2009-2018 Free Software
3 Foundation, Inc.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 /* Written by Jim Meyering. */
19
20 #include <config.h>
21
22 #include "memcasecmp.h"
23
24 #include <ctype.h>
25 #include <limits.h>
26
27 /* Like memcmp, but ignore differences in case.
28 Convert to upper case (not lower) before comparing so that
29 join -i works with sort -f. */
30
31 int
memcasecmp(const void * vs1,const void * vs2,size_t n)32 memcasecmp (const void *vs1, const void *vs2, size_t n)
33 {
34 size_t i;
35 char const *s1 = vs1;
36 char const *s2 = vs2;
37 for (i = 0; i < n; i++)
38 {
39 unsigned char u1 = s1[i];
40 unsigned char u2 = s2[i];
41 int U1 = toupper (u1);
42 int U2 = toupper (u2);
43 int diff = (UCHAR_MAX <= INT_MAX ? U1 - U2
44 : U1 < U2 ? -1 : U2 < U1);
45 if (diff)
46 return diff;
47 }
48 return 0;
49 }
50