usr/src/lib/libc/string/strstr.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strstr.c    5.2 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/cdefs.h>
#include <string.h>

/*
 * Find the first occurrence of find in s.
 */
char *
strstr(s, find)
        register const char *s, *find;
{
        register char c, sc;
        register size_t len;

        if ((c = *find++) != 0) {
                len = strlen(find);
                do {
                        do {
                                if ((sc = *s++) == 0)
                                        return (NULL);
                        } while (sc != c);
                } while (strncmp(s, find, len) != 0);
                s--;
        }
        return ((char *)s);
}