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set & use encoding options according to XTypes

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Two bits of the DDSI encoding "options" field are used by the XTypes
spec to indicate the amount of padding that had to be added at the end
to reach the nearest 4-byte boundary as required by the DDSI message
format.

These bits are now set in according with the spec, and for received
samples, the padding is subtracted from the inferred size of the data so
that, e.g., a struct T { octet x; } will never deserialise as a struct S
{ octet x, y; }.

Signed-off-by: Erik Boasson <eb@ilities.com>
This commit is contained in:
Erik Boasson 2019-05-14 17:46:32 +02:00 • committed by eboasson
parent 35fcc013af
commit 3574ac6903
2 changed files with 22 additions and 8 deletions
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22
src/core/ddsc/src/dds_stream.c
View file

@ -77,23 +77,27 @@ static void dds_cdr_alignto (dds_istream_t * __restrict s, uint32_t a)
assert (s->m_index < s->m_size);
}
static void dds_cdr_alignto_clear_and_resize (dds_ostream_t * __restrict s, uint32_t a, uint32_t extra)
static uint32_t dds_cdr_alignto_clear_and_resize (dds_ostream_t * __restrict s, uint32_t a, uint32_t extra)
{
const uint32_t m = s->m_index % a;
if (m == 0)
{
dds_cdr_resize (s, extra);
return 0;
}
else
{
uint32_t pad = a - m;
const uint32_t pad = a - m;
dds_cdr_resize (s, pad + extra);
while (pad--)
for (uint32_t i = 0; i < pad; i++)
s->m_buffer[s->m_index++] = 0;
return pad;
}
}
static void dds_cdr_alignto_clear_and_resize_be (dds_ostreamBE_t * __restrict s, uint32_t a, uint32_t extra)
static uint32_t dds_cdr_alignto_clear_and_resize_be (dds_ostreamBE_t * __restrict s, uint32_t a, uint32_t extra)
{
dds_cdr_alignto_clear_and_resize (&s->x, a, extra);
return dds_cdr_alignto_clear_and_resize (&s->x, a, extra);
}
static uint8_t dds_is_get1 (dds_istream_t * __restrict s)
@ -1644,13 +1648,15 @@ void dds_ostream_add_to_serdata_default (dds_ostream_t * __restrict s, struct dd
{
/* DDSI requires 4 byte alignment */
dds_cdr_alignto_clear_and_resize (s, 4, 0);
const uint32_t pad = dds_cdr_alignto_clear_and_resize (s, 4, 0);
assert (pad <= 3);
/* Reset data pointer as stream may have reallocated */
(*d) = (void *) s->m_buffer;
(*d)->pos = (s->m_index - (uint32_t) offsetof (struct ddsi_serdata_default, data));
(*d)->size = (s->m_size - (uint32_t) offsetof (struct ddsi_serdata_default, data));
(*d)->hdr.options = toBE2u ((uint16_t) pad);
}
void dds_ostreamBE_from_serdata_default (dds_ostreamBE_t * __restrict s, struct ddsi_serdata_default * __restrict d)
@ -1665,11 +1671,13 @@ void dds_ostreamBE_add_to_serdata_default (dds_ostreamBE_t * __restrict s, struc
{
/* DDSI requires 4 byte alignment */
dds_cdr_alignto_clear_and_resize_be (s, 4, 0);
const uint32_t pad = dds_cdr_alignto_clear_and_resize_be (s, 4, 0);
assert (pad <= 3);
/* Reset data pointer as stream may have reallocated */
(*d) = (void *) s->x.m_buffer;
(*d)->pos = (s->x.m_index - (uint32_t) offsetof (struct ddsi_serdata_default, data));
(*d)->size = (s->x.m_size - (uint32_t) offsetof (struct ddsi_serdata_default, data));
(*d)->hdr.options = toBE2u ((uint16_t) pad);
}

8
src/core/ddsi/src/ddsi_serdata_default.c
View file

@ -301,7 +301,13 @@ static struct ddsi_serdata_default *serdata_default_from_ser_common (const struc
const bool needs_bswap = (d->hdr.identifier != NATIVE_ENCODING);
d->hdr.identifier = NATIVE_ENCODING;
if (!dds_stream_normalize (d->data, d->pos, needs_bswap, tp, kind == SDK_KEY))
const uint32_t pad = fromBE2u (d->hdr.options) & 2;
if (d->pos < pad)
{
ddsi_serdata_unref (&d->c);
return NULL;
}
else if (!dds_stream_normalize (d->data, d->pos - pad, needs_bswap, tp, kind == SDK_KEY))
{
ddsi_serdata_unref (&d->c);
return NULL;