Enum Encoding 

pub enum Encoding {
    PlainCdr1,
    PlCdr1,
    PlainCdr2,
    DelimitedCdr,
    PlCdr2,
}

Which encoding a plan is computed for.

XCDR1 and XCDR2 differ in their framing: XCDR1 has no delimiter header, and @mutable uses PID headers there and EMHEADERs here. Primitive alignment is the same in both. OMG XTypes 1.3 §7.4.

Variants

PlainCdr1

XCDR1 without a parameter list. XTypes 1.3 §7.4.1.

PlCdr1

XCDR1 with a parameter list, for @mutable. XTypes 1.3 §7.4.1.2.

PlainCdr2

XCDR2 without a header. XTypes 1.3 §7.4.2.

DelimitedCdr

XCDR2 with a delimiter header, for @appendable.

PlCdr2

XCDR2 with a parameter list, for @mutable.

Implementations

impl Encoding

pub const ALL: [Self; 5]

Every encoding the layout planner covers.

pub const fn is_v1(self) -> bool

Whether this is an XCDR version 1 encoding.

pub const fn is_v2(self) -> bool

Whether this is an XCDR version 2 encoding.

pub const fn max_alignment(self) -> u8

The largest alignment any primitive takes.

XTypes 1.3 §7.4.1, the XCDR stream operations table, defines it outright:

MAXALIGN( VERSION2) = 4 MAXALIGN( VERSION1) = 8 MAXALIGN( VERSION_NONE) = 8

and ALIGN(N) aligns to MIN(N, XCDR.maxalign). §7.6.8 repeats it for the key holder: “the maximum alignment in PLAIN_CDR2 (i.e., 4)”.

Why this reads as a correction

It was briefly eight for both versions, on the authority of a wire vector V-3 in crates/cdr/tests/xcdr2_wire_vectors.rs at e1f3af895. That vector is not an OMG artefact — its header cites §7.4.2 but its byte table was computed by hand, and it pads the trailing double to align(8) for a total of 48 bytes. Three independent sources say 44:

• the spec text above,
• Cyclone DDS, src/core/cdr/src/dds_cdrstream.c:239 — xcdr_version == DDSI_RTPS_CDR_ENC_VERSION_2 ? MK_ALIGN(4) : MK_ALIGN(8), and :2435 .alignmask = (… ? 3 : 7),
• Fast CDR, src/cpp/Cdr.cpp:238 — align64_ = 4 on reading an XCDRv2 encapsulation, 8 otherwise.

Measured, not read: @final struct Point { long x; double y; } with x=1, y=2.0 comes off Cyclone’s and RTI Connext 7.7’s own serialisers as twelve payload bytes, 010000000000000000000040, with the double at offset 4. tests/fixtures/vendor_bytes.md records the runs.

Trait Implementations

impl Clone for Encoding

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Encoding

impl Debug for Encoding

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Encoding

impl Hash for Encoding

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Encoding

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for Encoding

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for Encoding

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for Encoding