/**
* duser - Manage MajorDomo lists
* Copyright (C) 2011 Joseph Hunkeler <jhunkeler@gmail.com, jhunk@stsci.edu>
*
* This file is part of duser.
*
* duser is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* duser 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with duser. If not, see <http://www.gnu.org/licenses/>.
**/

#include <stdio.h>
#include <string.h>
#include <ctype.h>

/*
 * Locate substring
 *
 * The strstr() function finds the first occurrence of the substring needle 
 * in the string haystack. The terminating '\0' characters are not compared. 
 *
 * The strcasestr() function is like strstr(), but ignores the 
 * case of both arguments. 
 */
char *strcasestr(const char *s, const char *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);
}