freeswitch/libs/sofia-sip/libsofia-sip-ua/su/strcasestr.c
2008-12-16 18:05:22 +00:00

74 lines
1.8 KiB
C

/*
* This file is part of the Sofia-SIP package
*
* Copyright (C) 2005 Nokia Corporation.
*
* Contact: Pekka Pessi <pekka.pessi@nokia.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
*/
/**@internal @file strcasestr.c
* @brief Backup implementation of strcasestr()
*
* @author Pekka Pessi <Pekka.Pessi@nokia.com>
*/
#include "config.h"
#include <ctype.h>
#include <stddef.h>
/* Naive implementation of strcasestr() */
char *strcasestr(const char *haystack,
const char *needle)
{
unsigned char lcn, ucn;
unsigned i;
if (haystack == NULL || needle == NULL)
return NULL;
lcn = ucn = needle[0];
if (isupper(lcn))
lcn = tolower(lcn);
else if (islower(ucn))
ucn = toupper(ucn);
if (lcn == 0)
return (char *)haystack;
while (haystack[0] != 0) {
if (lcn == haystack[0] || ucn == haystack[0]) {
for (i = 1; ; i++) {
char n = needle[i], h = haystack[i];
if (n == 0)
return (char *)haystack;
if (h == 0)
return NULL;
if (isupper(n)) n = tolower(n);
if (isupper(h)) h = tolower(h);
if (n != h)
break;
}
}
haystack++;
}
return NULL; /* Not found */
}