/*****************************************************************************

 * strnstr.c: BSD strnstr() replacement

 *****************************************************************************

 * Copyright © 2015 VLC authors and VideoLAN

 *

 * This program 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 program 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 program; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.

 *****************************************************************************/

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <string.h>

#include <assert.h>

char * strnstr (const char *haystack, const char *needle, size_t len)

{

    assert(needle != NULL);

    const size_t i = strlen(needle);

    if (i == 0) /* corner case (if haystack is NULL, memcmp not allowed) */

        return (char *)haystack;

    if( len < i )

      return NULL;

    size_t count = len - i;

    do

    {

      if( memcmp(haystack, needle, i) == 0 )

        return (char*) haystack;

      haystack++;

    }

    while(count--);

    return NULL;

}