#ifndef HAVE_STRSTR
	extern char *strstr (char *text, char *pattern);
#endif /* HAVE_STRSTR */


#ifndef HAVE_STRSTR
/*
 * ANSI C strstr () - Uses Boyer-Moore algorithm.
 */
char *
strstr (
	char *text,
	char *pattern)
{
	register unsigned char *p, *t;
	register int i, j, *delta;
	register size_t p1;
	int deltaspace[256];
	size_t textlen;
	size_t patlen;

	textlen = strlen (text);
	patlen = strlen (pattern);

	/* algorithm fails if pattern is empty */
	if ((p1 = patlen) == 0)
		return (text);

	/* code below fails (whenever i is unsigned) if pattern too long */
	if (p1 > textlen)
		return (NULL);

	/* set up deltas */
	delta = deltaspace;
	for (i = 0; i <= 255; i++)
		delta[i] = p1;
	for (p = (unsigned char *) pattern, i = p1; --i > 0;)
		delta[*p++] = i;

	/*
	 * From now on, we want patlen - 1.
	 * In the loop below, p points to the end of the pattern,
	 * t points to the end of the text to be tested against the
	 * pattern, and i counts the amount of text remaining, not
	 * including the part to be tested.
	 */
	p1--;
	p = (unsigned char *) pattern + p1;
	t = (unsigned char *) text + p1;
	i = textlen - patlen;
	forever {
		if (*p == *t && memcmp ((p - p1), (t - p1), p1) == 0)
			return ((char *)t - p1);
		j = delta[*t];
		if (i < j)
			break;
		i -= j;
		t += j;
	}
	return (NULL);
}
#endif