1 /* $NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $ */
2
3 /*-
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #if defined(LIBC_SCCS) && !defined(lint)
36 __RCSID("$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $");
37 __RCSID("$NetBSD: strncasecmp.c,v 1.2 2007/06/04 18:19:27 christos Exp $");
38 #endif /* LIBC_SCCS and not lint */
39
40 #include "file.h"
41
42 #include <assert.h>
43 #include <ctype.h>
44 #include <string.h>
45
46 static int
_strncasecmp(const char * s1,const char * s2,size_t n)47 _strncasecmp(const char *s1, const char *s2, size_t n)
48 {
49 if (n != 0) {
50 const unsigned char *us1 = (const unsigned char *)s1,
51 *us2 = (const unsigned char *)s2;
52
53 do {
54 if (tolower(*us1) != tolower(*us2++))
55 return tolower(*us1) - tolower(*--us2);
56 if (*us1++ == '\0')
57 break;
58 } while (--n != 0);
59 }
60 return 0;
61 }
62
63 /*
64 * Find the first occurrence of find in s, ignore case.
65 */
66 char *
strcasestr(const char * s,const char * find)67 strcasestr(const char *s, const char *find)
68 {
69 char c, sc;
70 size_t len;
71
72 if ((c = *find++) != 0) {
73 c = tolower((unsigned char)c);
74 len = strlen(find);
75 do {
76 do {
77 if ((sc = *s++) == 0)
78 return (NULL);
79 } while ((char)tolower((unsigned char)sc) != c);
80 } while (_strncasecmp(s, find, len) != 0);
81 s--;
82 }
83 return (char *)(intptr_t)(s);
84 }
85
