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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <assert.h>
28#include <ctype.h>
29#include <strings.h>
30
31extern "C" {
32
33static char foldcase(char ch)
34{
35 if (isalpha(ch))
36 return tolower(ch);
37 return ch;
38}
39
40int strcasecmp(const char* s1, const char* s2)
41{
42 for (; foldcase(*s1) == foldcase(*s2); ++s1, ++s2) {
43 if (*s1 == 0)
44 return 0;
45 }
46 return foldcase(*(const unsigned char*)s1) < foldcase(*(const unsigned char*)s2) ? -1 : 1;
47}
48
49int strncasecmp(const char* s1, const char* s2, size_t n)
50{
51 if (!n)
52 return 0;
53 do {
54 if (foldcase(*s1) != foldcase(*s2++))
55 return foldcase(*(const unsigned char*)s1) - foldcase(*(const unsigned char*)--s2);
56 if (*s1++ == 0)
57 break;
58 } while (--n);
59 return 0;
60}
61}