source: tags/initial/fig2dev/strstr.c

/*
 * TransFig: Facility for Translating Fig code
 * Copyright (c) 1985 Supoj Sutantavibul
 * Copyright (c) 1991 Micah Beck
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation. The authors make no representations about the suitability 
 * of this software for any purpose.  It is provided "as is" without express 
 * or implied warranty.
 *
 * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 *
 */

#define NULL    0

/*
 * Find the first occurrence of s2 in s1.
 */
char *
strstr(s1, s2)
        register char *s1, *s2;
{
        register int i, len, n;

        if (s2[0] == '\0')
                return(s1);
        len = strlen(s2);
        n = strlen(s1) - len;
        for (i = 0; i <= n; i++)
                if (strcmp(s1 + i, s2) == 0)
                        return(s1 + i);
        return(NULL);
}