strcasestr.c revision 268515 
12116Sjkh/*	$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $	*/
22116Sjkh
32116Sjkh/*-
42116Sjkh * Copyright (c) 1990, 1993
52116Sjkh *	The Regents of the University of California.  All rights reserved.
62116Sjkh *
72116Sjkh * This code is derived from software contributed to Berkeley by
82116Sjkh * Chris Torek.
92116Sjkh *
102116Sjkh * Redistribution and use in source and binary forms, with or without
112116Sjkh * modification, are permitted provided that the following conditions
122116Sjkh * are met:
132116Sjkh * 1. Redistributions of source code must retain the above copyright
142116Sjkh *    notice, this list of conditions and the following disclaimer.
152116Sjkh * 2. Redistributions in binary form must reproduce the above copyright
162116Sjkh *    notice, this list of conditions and the following disclaimer in the
172116Sjkh *    documentation and/or other materials provided with the distribution.
182116Sjkh * 3. Neither the name of the University nor the names of its contributors
192116Sjkh *    may be used to endorse or promote products derived from this software
202116Sjkh *    without specific prior written permission.
212116Sjkh *
222116Sjkh * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
232116Sjkh * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
242116Sjkh * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
252116Sjkh * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
262116Sjkh * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
272116Sjkh * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
282116Sjkh * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
292116Sjkh * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
302116Sjkh * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
312116Sjkh * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
322116Sjkh * SUCH DAMAGE.
332116Sjkh */
342116Sjkh
352116Sjkh#if defined(LIBC_SCCS) && !defined(lint)
3623577Sbde__RCSID("$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $");
37213337Sdim__RCSID("$NetBSD: strncasecmp.c,v 1.2 2007/06/04 18:19:27 christos Exp $");
382116Sjkh#endif /* LIBC_SCCS and not lint */
392116Sjkh
402116Sjkh#include "file.h"
412116Sjkh
4261335Sbde#include <assert.h>
432116Sjkh#include <ctype.h>
44192760Sattilio#include <string.h>
45217108Skib
46217108Skibstatic int
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 */
66char *
67strcasestr(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