Function sbuf_setpos

freebsd/kern/subr_sbuf.c:331–350

* Set the sbuf's end position to an arbitrary value. * Effectively truncates the sbuf at the new position. */

 * Effectively truncates the sbuf at the new position.
 */
int
sbuf_setpos(struct sbuf *s, ssize_t pos)
{

	assert_sbuf_integrity(s);
	assert_sbuf_state(s, 0);

	KASSERT(pos >= 0,
	    ("attempt to seek to a negative position (%jd)", (intmax_t)pos));
	KASSERT(pos < s->s_size,
	    ("attempt to seek past end of sbuf (%jd >= %jd)",
	    (intmax_t)pos, (intmax_t)s->s_size));
	KASSERT(!SBUF_ISSECTION(s),
	    ("attempt to seek when in a section"));

	if (pos < 0 || pos > s->s_len)
		return (-1);
	s->s_len = pos;
	return (0);
}

/*
 * Drain into a counter.  Counts amount of data without producing output.