Function sbuf_put_bytes

freebsd/kern/subr_sbuf.c:435–469

* Append bytes to an sbuf. This is the core function for appending * to an sbuf and is the main place that deals with extending the * buffer and marking overflow. */

 * buffer and marking overflow.
 */
static void
sbuf_put_bytes(struct sbuf *s, const char *buf, size_t len)
{
	size_t n;

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

	if (s->s_error != 0)
		return;
	while (len > 0) {
		if (SBUF_FREESPACE(s) <= 0) {
			/*
			 * If there is a drain, use it, otherwise extend the
			 * buffer.
			 */
			if (s->s_drain_func != NULL)
				(void)sbuf_drain(s);
			else if (sbuf_extend(s, len > INT_MAX ? INT_MAX : len)
			    < 0)
				s->s_error = ENOMEM;
			if (s->s_error != 0)
				return;
		}
		n = SBUF_FREESPACE(s);
		if (len < n)
			n = len;
		memcpy(&s->s_buf[s->s_len], buf, n);
		s->s_len += n;
		if (SBUF_ISSECTION(s))
			s->s_sect_len += n;
		len -= n;
		buf += n;
	}
}

static void
sbuf_put_byte(struct sbuf *s, char c)