libc/newlib/libc/string/strcasestr.c

99 lines
2.9 KiB
C

/*
FUNCTION
<<strcasestr>>---case-insensitive character string search
INDEX
strcasestr
ANSI_SYNOPSIS
#include <string.h>
char *strcasestr(const char *<[s]>, const char *<[find]>);
TRAD_SYNOPSIS
#include <string.h>
int strcasecmp(<[s]>, <[find]>)
char *<[s]>;
char *<[find]>;
DESCRIPTION
<<strcasestr>> searchs the string <[s]> for
the first occurrence of the sequence <[find]>. <<strcasestr>>
is identical to <<strstr>> except the search is
case-insensitive.
RETURNS
A pointer to the first case-insensitive occurrence of the sequence
<[find]> or <<NULL>> if no match was found.
PORTABILITY
<<strcasestr>> is in the Berkeley Software Distribution.
<<strcasestr>> requires no supporting OS subroutines. It uses
tolower() from elsewhere in this library.
QUICKREF
strcasestr
*/
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include <ctype.h>
#include <string.h>
/*
* Find the first occurrence of find in s, ignore case.
*/
char *
strcasestr(s, find)
const char *s, *find;
{
char c, sc;
size_t len;
if ((c = *find++) != 0) {
c = tolower((unsigned char)c);
len = strlen(find);
do {
do {
if ((sc = *s++) == 0)
return (NULL);
} while ((char)tolower((unsigned char)sc) != c);
} while (strncasecmp(s, find, len) != 0);
s--;
}
return ((char *)s);
}