Enum bsn1::Length

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

Length represents ASN.1 length.

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

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 from_bytes(bytes: &[u8]) -> Result<Self, Error>

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

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

This method is same to TryFrom implementation.

Examples

use bsn1::Length;

let mut bytes = vec![0x05]; // represents Definite(5).
let len = Length::from_bytes(&bytes).unwrap();
assert_eq!(Length::Definite(5), len);

// Ignores the last extra octet 0x03.
bytes.push(0x03);
let len = Length::from_bytes(&bytes).unwrap();
assert_eq!(Length::Definite(5), len);

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

Serializes length .

Examples

use bsn1::Length;
use std::convert::TryFrom;

let length = Length::Definite(3);
let bytes = length.to_bytes();

let deserialized = Length::try_from(bytes.as_ref()).unwrap();
assert_eq!(length, 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);

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,

Feeds a slice of this type into the given Hasher.

impl PartialEq<Length> for Length

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl TryFrom<&[u8]> for Length

fn try_from(bytes: &[u8]) -> Result<Self, Self::Error>

Parses bytes starting with length octets and tries to create a new instance.

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

This function is same to from_bytes.

type Error = Error

The type returned in the event of a conversion error.

impl Copy for Length

impl Eq for Length

impl StructuralEq for Length

impl StructuralPartialEq for Length