Enum MapDelimiter 

pub enum MapDelimiter {
    EitherHalf,
    ValueOnly,
}

Which of a map’s two halves decides whether the map carries a delimiter under XCDR2.

Separate from CollectionDelimiterPolicy because it is a separate question and one measured implementation answers the two differently. That policy says which element types exempt a collection; this says which of a map’s two element types is asked.

The measurement

tests/interop-results/sources/vendor-corpus.tsv, Fast DDS 3.6.1, encoding version 2, both byte orders. Little endian, the leading word of each payload:

case	the map	Fast DDS writes
map-key-long	map<long, long>	03000000 — the entry count
map-key-string	map<string, long>	03000000 — the entry count
map-empty	map<string, long>	00000000 — the entry count
map-value-string	map<long, string>	22000000 — a DHEADER
map-value-struct	map<long, Cell>	22000000 — a DHEADER
map-value-sequence	map<long, sequence<long>>	1c000000 — a DHEADER
map-nested	map<long, map<long, long>>	1c000000 — a DHEADER

A string key exempts nothing and a string value does not, so the question Fast DDS asks is the value’s alone. Twelve recorded rows separate the two readings — map-empty, map-key-string and typedef-of-map in both orders under both of their halves — and they were the last twelve rows of the Fast DDS column that no single setting reached.

Variants

EitherHalf

Either half. Rule (14) of XTypes 1.3 §7.4.3.5.3 exempts a map only where the key and the value are primitive, so a map<string, long> is delimited by rule (15).

The default, and the clause’s reading.

ValueOnly

The value alone, whatever the key is. Fast CDR 2.3.5’s.

Implementations

impl MapDelimiter

pub const ALL: [Self; 2]

Both readings.

pub const fn is_default(self) -> bool

Whether this is the default.

pub const fn as_str(self) -> &'static str

Short name, for configuration and diagnostics.

pub fn parse(value: &str) -> Option<Self>

Parse a configuration value.

An unknown value returns None rather than falling back to the default: a typo in a wire-affecting setting must be loud.

Trait Implementations

impl Clone for MapDelimiter

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 MapDelimiter

impl Debug for MapDelimiter

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

Formats the value using the given formatter.

impl Default for MapDelimiter

fn default() -> Self

Returns the “default value” for a type.

impl Eq for MapDelimiter

impl Hash for MapDelimiter

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 MapDelimiter

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 MapDelimiter

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for MapDelimiter

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 MapDelimiter