/*
* 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);
}
/*
* Extend an vsb.
*/
static int
VSB_extend(struct vsb *s, int addlen)
{
char *newbuf;
int newsize;
if (!VSB_CANEXTEND(s))
return (-1);
newsize = VSB_extendsize(s->s_size + addlen);
newbuf = SBMALLOC(newsize);
if (newbuf == NULL)
return (-1);
memcpy(newbuf, s->s_buf, s->s_size);
if (VSB_ISDYNAMIC(s))
SBFREE(s->s_buf);
else
VSB_SETFLAG(s, VSB_DYNAMIC);
s->s_buf = newbuf;
s->s_size = newsize;
return (0);
}
/*
* Extend an vsb.
*/
static ssize_t
VSB_extend(struct vsb *s, ssize_t addlen)
{
char *newbuf;
ssize_t newsize;
if (!VSB_CANEXTEND(s))
return (-1);
newsize = VSB_extendsize(s->s_size + addlen);
if (VSB_ISDYNAMIC(s))
newbuf = realloc(s->s_buf, newsize);
else
newbuf = SBMALLOC(newsize);
if (newbuf == NULL)
return (-1);
if (!VSB_ISDYNAMIC(s)) {
memcpy(newbuf, s->s_buf, s->s_size);
VSB_SETFLAG(s, VSB_DYNAMIC);
}
s->s_buf = newbuf;
s->s_size = newsize;
return (0);
}
