Enum Length

pub enum Length {
    Indefinite,
    Definite(usize),
}

Length represents ASN.1 length.

Note that Length represents the count of the contents octets in ASN.1. The total byte size of BER, DER, and CER is greater than that. (BER, DER, and CER are composed of identifier, length, and contents.)

Caution

Length implements PartialEq and PartialOrd, but Eq nor Ord, because ‘Indefinite length’ is not comparable.

Variants

Indefinite

Represents ‘Indefinite’ length.

‘Indefinite’ is only for ‘BER’, and the contents must end with ‘EOC’ octets.

Definite(usize)

‘Definite’ is for ‘BER’, ‘DER’, and ‘CER’, and represents the byte count of the contents.

Implementations

impl Length

pub fn parse<R>(readable: &mut R) -> Result<Self, Error>

where R: ?Sized + Read,

Parses readable starting with length octets and tries to creates a new instance.

This function ignores extra octet(s) at the end of readable if any.

Examples

use bsn1::Length;

// Serializes Definite(5).
let length = Length::Definite(5);
let mut serialized = Vec::from(&length.to_bytes()[..]);

// Parses the serialized bytes.
let deserialized = Length::parse(&mut &serialized[..]).unwrap();
assert_eq!(length, deserialized);

// The extra octets at the end does not affect the result.
serialized.push(0x03);
serialized.push(0x04);
let deserialized = Length::parse(&mut &serialized[..]).unwrap();
assert_eq!(length, deserialized);

pub fn to_bytes(self) -> impl Deref<Target = [u8]>

Serializes self.

Examples

use bsn1::Length;

// Serializes Definite(3), and deserializes it.
// The result is Definite(3).
let bytes = Length::Definite(3).to_bytes();
let deserialized = Length::parse(&mut &*bytes).unwrap();
assert_eq!(Length::Definite(3), deserialized);

pub const fn len(self) -> usize

Returns the byte count of the octets that self is serialized.

Examples

use bsn1::Length;

// The length of INDEFINITE is always 1.
assert_eq!(Length::Indefinite.len(), 1);

// The length is 1 if the value is less than or equals to 127.
assert_eq!(Length::Definite(0).len(), 1);
assert_eq!(Length::Definite(127).len(), 1);

// The length is 2 if the value is 128.
assert_eq!(Length::Definite(128).len(), 2);

pub const fn definite(self) -> Option<usize>

Converts self to Option<usize>.

Returns None if self is Indefinite; otherwise, wraps the inner number in Some and returns it.

Examples

use bsn1::Length;

let length = Length::Indefinite;
assert_eq!(length.definite(), None);

let length = Length::Definite(45);
assert_eq!(length.definite(), Some(45));

pub const fn is_indefinite(self) -> bool

Returns true if self is Indefinite; otherwise false.

Examples

use bsn1::Length;

let length = Length::Indefinite;
assert_eq!(length.is_indefinite(), true);

let length = Length::Definite(12);
assert_eq!(length.is_indefinite(), false);

pub const fn is_definite(self) -> bool

Returns false if self is Indefinite; otherwise true.

Examples

use bsn1::Length;

let length = Length::Indefinite;
assert_eq!(length.is_definite(), false);

let length = Length::Definite(12);
assert_eq!(length.is_definite(), true);

Trait Implementations

impl Clone for Length

fn clone(&self) -> Length

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Length

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

Formats the value using the given formatter.

impl Hash for Length

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 PartialEq for Length

fn eq(&self, other: &Self) -> 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, 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 Copy for Length