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/*

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.

 *

 * 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>

#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)

# define CMP_FUNC strncasecmp

# include "str-two-way.h"

#endif

/*

 * Find the first occurrence of find in s, ignore case.

 */

char *

strcasestr(s, find)

        const char *s, *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 */

}