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/*
FUNCTION
<<strcasestr>>---case-insensitive character string search
INDEX
strcasestr
SYNOPSIS
#include <string.h>
char *strcasestr(const char *<[s]>, const 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.
*
* The quadratic 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.
*/
/* Linear algorithm Copyright (C) 2008 Eric Blake
* Permission to use, copy, modify, and distribute the linear portion of
* software is freely granted, provided that this notice is preserved.
*/
#include <sys/cdefs.h>
#include <ctype.h>
#include <string.h>
#include <strings.h>
#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
# define RETURN_TYPE char *
# define AVAILABLE(h, h_l, j, n_l) \
(!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l)) \
&& ((h_l) = (j) + (n_l)))
# define CANON_ELEMENT(c) tolower (c)
#if __GNUC_PREREQ (4, 2)
/* strncasecmp uses signed char, CMP_FUNC is expected to use unsigned char. */
#pragma GCC diagnostic ignored "-Wpointer-sign"
#endif
# define CMP_FUNC strncasecmp
# include "str-two-way.h"
#endif
/*
* Find the first occurrence of find in s, ignore case.
*/
char *
strcasestr (const char *s,
const char *find)
{
#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
/* Less code size, but quadratic performance in the worst case. */
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);
#else /* compilation for speed */
/* Larger code size, but guaranteed linear performance. */
const char *haystack = s;
const char *needle = find;
size_t needle_len; /* Length of NEEDLE. */
size_t haystack_len; /* Known minimum length of HAYSTACK. */
int ok = 1; /* True if NEEDLE is prefix of HAYSTACK. */
/* Determine length of NEEDLE, and in the process, make sure
HAYSTACK is at least as long (no point processing all of a long
NEEDLE if HAYSTACK is too short). */
while (*haystack && *needle)
ok &= (tolower ((unsigned char) *haystack++)
== tolower ((unsigned char) *needle++));
if (*needle)
return NULL;
if (ok)
return (char *) s;
needle_len = needle - find;
haystack = s + 1;
haystack_len = needle_len - 1;
/* Perform the search. */
if (needle_len < LONG_NEEDLE_THRESHOLD)
return two_way_short_needle ((const unsigned char *) haystack,
haystack_len,
(const unsigned char *) find, needle_len);
return two_way_long_needle ((const unsigned char *) haystack, haystack_len,
(const unsigned char *) find, needle_len);
#endif /* compilation for speed */
}
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