Struct Label 

pub struct Label(/* private fields */);

Available on crate feature net only.

A single DNS label in presentation format.

Label is a borrowed, unsized view: you’ll always work with &Label, produced either by Label::from_str (validated) or by internal helpers that already maintain the invariant.

Invariants

A &Label’s contents always satisfy:

• non-empty, at most Label::MAX_LEN (63) bytes
• either the single-byte wildcard form "*", or a sequence of ASCII alphanumerics, _, and -, with no leading or trailing -

Equality / ordering

Label’s PartialEq, Eq, Hash, Ord, and PartialOrd impls are ASCII-case-insensitive. "Foo", "foo", and "FOO" compare equal and hash to the same value.

Implementations

impl Label

pub const MAX_LEN: usize = 63

Maximum byte length of a single label (RFC 1035).

pub fn from_str(s: &str) -> Result<&Label, LabelError>

Parses a single label.

Errors

Returns a LabelError if s violates any invariant.

pub fn as_str(&self) -> &str

Returns the label as its underlying string.

pub fn len(&self) -> usize

Returns the label length in bytes.

A label is non-empty by invariant, so length is always >= 1; there is intentionally no is_empty method.

pub fn is_wildcard(&self) -> bool

Returns true if this is the wildcard label "*".

Trait Implementations

impl AsRef<str> for Label

fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.

impl Debug for Label

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

Formats the value using the given formatter.

impl Display for Label

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

Formats the value using the given formatter.

impl Hash for Label

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

where H: Hasher,

Feeds this value into the given Hasher.

impl Ord for Label

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

This method returns an Ordering between self and other.

impl PartialEq for Label

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Label

fn partial_cmp(&self, other: &Label) -> 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 Eq for Label