/*
* Format the given argument list and append the resulting string to an vsb.
*/
int
VSB_vprintf(struct vsb *s, const char *fmt, va_list ap)
{
va_list ap_copy;
int len;
assert_VSB_integrity(s);
assert_VSB_state(s, 0);
KASSERT(fmt != NULL,
("%s called with a NULL format string", __func__));
if (s->s_error != 0)
return (-1);
_vsb_indent(s);
/*
* For the moment, there is no way to get vsnprintf(3) to hand
* back a character at a time, to push everything into
* VSB_putc_func() as was done for the kernel.
*
* In userspace, while drains are useful, there's generally
* not a problem attempting to malloc(3) on out of space. So
* expand a userland vsb if there is not enough room for the
* data produced by VSB_[v]printf(3).
*/
do {
va_copy(ap_copy, ap);
len = vsnprintf(&s->s_buf[s->s_len], VSB_FREESPACE(s) + 1,
fmt, ap_copy);
va_end(ap_copy);
} while (len > VSB_FREESPACE(s) &&
VSB_extend(s, len - VSB_FREESPACE(s)) == 0);
/*
* s->s_len is the length of the string, without the terminating nul.
* When updating s->s_len, we must subtract 1 from the length that
* we passed into vsnprintf() because that length includes the
* terminating nul.
*
* vsnprintf() returns the amount that would have been copied,
* given sufficient space, so don't over-increment s_len.
*/
if (VSB_FREESPACE(s) < len)
len = VSB_FREESPACE(s);
s->s_len += len;
if (!VSB_HASROOM(s) && !VSB_CANEXTEND(s))
s->s_error = ENOMEM;
KASSERT(s->s_len < s->s_size,
("wrote past end of vsb (%d >= %d)", s->s_len, s->s_size));
if (s->s_error != 0)
return (-1);
return (0);
}
static void
_vsb_indent(struct vsb *s)
{
if (s->s_indent == 0 || s->s_error != 0 ||
(s->s_len > 0 && s->s_buf[s->s_len - 1] != '\n'))
return;
if (VSB_FREESPACE(s) <= s->s_indent &&
VSB_extend(s, s->s_indent) < 0) {
s->s_error = ENOMEM;
return;
}
memset(s->s_buf + s->s_len, ' ', s->s_indent);
s->s_len += s->s_indent;
}
/*
* Append a byte to an vsb. This is the core function for appending
* to an vsb and is the main place that deals with extending the
* buffer and marking overflow.
*/
static void
VSB_put_byte(struct vsb *s, int c)
{
assert_VSB_integrity(s);
assert_VSB_state(s, 0);
if (s->s_error != 0)
return;
if (VSB_FREESPACE(s) <= 0) {
if (VSB_extend(s, 1) < 0)
s->s_error = ENOMEM;
if (s->s_error != 0)
return;
}
s->s_buf[s->s_len++] = (char)c;
}
/*
* Append a byte string to an vsb.
*/
int
VSB_bcat(struct vsb *s, const void *buf, ssize_t len)
{
assert_VSB_integrity(s);
assert_VSB_state(s, 0);
assert(len >= 0);
if (s->s_error != 0)
return (-1);
if (len == 0)
return (0);
_vsb_indent(s);
if (len > VSB_FREESPACE(s)) {
if (VSB_extend(s, len - VSB_FREESPACE(s)) < 0)
s->s_error = ENOMEM;
if (s->s_error != 0)
return (-1);
}
memcpy(s->s_buf + s->s_len, buf, len);
s->s_len += len;
return (0);
}
