Struct Header 

pub struct Header {
    tag: Tag,
    length: Length,
    constructed: bool,
}

ASN.1 DER headers: tag + length component of TLV-encoded values

Examples

use der::{Decode, Header, Length, Reader, SliceReader, Tag};

let mut reader = SliceReader::new(&[0x04, 0x02, 0x31, 0x32]).unwrap();
let header = Header::decode(&mut reader).expect("valid header");

assert_eq!(header, Header::new(Tag::OctetString, Length::new(2)));

assert_eq!(reader.read_slice(2u8.into()).unwrap(), b"12");

use der::{Encode, Header, Length, Tag};
let header = Header::new(Tag::Sequence, Length::new(256));

// Header of 256-byte SEQUENCE is 4-byte long
assert_eq!(header.encoded_len(), Ok(Length::new(4)));

Fields

tag: Tag

length: Length

constructed: bool

Implementations

impl Header

pub fn new(tag: Tag, length: Length) -> Header

Create a new Header from a Tag and a Length.

pub fn tag(&self) -> Tag

Tag of this header.

pub fn length(&self) -> Length

Length of this header.

pub fn is_constructed(&self) -> bool

True if the Tag of this header has its constructed bit set.

pub fn with_length(&self, length: Length) -> Header

Copy of header with adjusted length.

pub fn peek<'a>(reader: &impl Reader<'a>) -> Result<Header, Error>

Peek forward in the reader, attempting to decode a Header at the current position.

Does not modify the reader’s state.

Errors

Returns Error in the event a header decoding error occurred.

Trait Implementations

impl Clone for Header

fn clone(&self) -> Header

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Header

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

Formats the value using the given formatter.

impl<'a> Decode<'a> for Header

type Error = Error

Type returned in the event of a decoding error.

fn decode<R>(reader: &mut R) -> Result<Header, Error>

where R: Reader<'a>,

Attempt to decode this TLV message using the provided decoder.

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

Parse Self from the provided DER-encoded byte slice.

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

Parse Self from the provided DER-encoded byte slice.

impl DerOrd for Header

fn der_cmp(&self, other: &Header) -> Result<Ordering, Error>

Return an Ordering between self and other when serialized as ASN.1 DER.

impl Encode for Header

fn encoded_len(&self) -> Result<Length, Error>

Compute the length of this TLV object in bytes when encoded as ASN.1 DER.

fn encode(&self, writer: &mut impl Writer) -> Result<(), Error>

Encode this TLV object as ASN.1 DER using the provided Writer.

fn encode_to_slice<'a>(&self, buf: &'a mut [u8]) -> Result<&'a [u8], Error>

Encode this TLV object to the provided byte slice, returning a sub-slice containing the encoded message.

fn encode_to_vec(&self, buf: &mut Vec<u8>) -> Result<Length, Error>

Encode this TLV object as ASN.1 DER, appending it to the provided byte vector.

fn to_der(&self) -> Result<Vec<u8>, Error>

Encode this TLV object as ASN.1 DER, returning a byte vector.

impl PartialEq for Header

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

impl Eq for Header

impl StructuralPartialEq for Header