Struct Length 

pub struct Length(pub u32);

A type for representing data set content length, in bytes. An internal value of 0xFFFF_FFFF represents an undefined (unspecified) length, which would have to be determined with a traversal based on the content’s encoding.

This also means that numeric comparisons and arithmetic do not function the same way as primitive number types:

Two length of undefined length are not equal.

assert_ne!(Length::UNDEFINED, Length::UNDEFINED);

Any addition or subtraction with at least one undefined length results in an undefined length.

assert!((Length::defined(64) + Length::UNDEFINED).is_undefined());
assert!((Length::UNDEFINED + 8).is_undefined());

Comparing between at least one undefined length is always false.

assert!(Length::defined(16) < Length::defined(64));
assert!(!(Length::UNDEFINED < Length::defined(64)));
assert!(!(Length::UNDEFINED > Length::defined(64)));

assert!(!(Length::UNDEFINED < Length::UNDEFINED));
assert!(!(Length::UNDEFINED > Length::UNDEFINED));
assert!(!(Length::UNDEFINED <= Length::UNDEFINED));
assert!(!(Length::UNDEFINED >= Length::UNDEFINED));

Tuple Fields

0: u32

Implementations

impl Length

pub const UNDEFINED: Self

A length that is undefined.

pub fn new(len: u32) -> Self

Create a new length value from its internal representation. This is equivalent to Length(len).

pub fn defined(len: u32) -> Self

Create a new length value with the given number of bytes.

Panic

This function will panic if len represents an undefined length.

impl Length

pub fn is_undefined(self) -> bool

Check whether this length is undefined (unknown).

pub fn is_defined(self) -> bool

Check whether this length is well defined (not undefined).

pub fn get(self) -> Option<u32>

Fetch the concrete length value, if available. Returns None if it represents an undefined length.

pub fn inner_eq(self, other: Length) -> bool

Check whether the length is equally specified as another length. Unlike the implemented PartialEq, two undefined lengths are considered equivalent by this method.

Trait Implementations

impl Add for Length

type Output = Length

The resulting type after applying the + operator.

fn add(self, rhs: Length) -> Self::Output

Performs the + operation.

impl Add<i32> for Length

type Output = Length

The resulting type after applying the + operator.

fn add(self, rhs: i32) -> Self::Output

Performs the + operation.

impl Clone for Length

fn clone(&self) -> Length

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Length

impl Debug for Length

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

Formats the value using the given formatter.

impl Display for Length

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

Formats the value using the given formatter.

impl From<u32> for Length

fn from(o: u32) -> Self

Converts to this type from the input type.

impl PartialEq for Length

fn eq(&self, rhs: &Length) -> 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 Length

fn partial_cmp(&self, rhs: &Length) -> 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 Sub for Length

type Output = Length

The resulting type after applying the - operator.

fn sub(self, rhs: Length) -> Self::Output

Performs the - operation.

impl Sub<i32> for Length

type Output = Length

The resulting type after applying the - operator.

fn sub(self, rhs: i32) -> Self::Output

Performs the - operation.

impl SubAssign for Length

fn sub_assign(&mut self, rhs: Length)

Performs the -= operation.

impl SubAssign<i32> for Length

fn sub_assign(&mut self, rhs: i32)

Performs the -= operation.