Trait der::Reader

pub trait Reader<'r>: Sized {
    // Required methods
    fn input_len(&self) -> Length;
    fn peek_byte(&self) -> Option<u8>;
    fn peek_header(&self) -> Result<Header>;
    fn position(&self) -> Length;
    fn read_slice(&mut self, len: Length) -> Result<&'r [u8]>;

    // Provided methods
    fn context_specific<T>(
        &mut self,
        tag_number: TagNumber,
        tag_mode: TagMode,
    ) -> Result<Option<T>>
       where T: DecodeValue<'r> + FixedTag { ... }
    fn decode<T: Decode<'r>>(&mut self) -> Result<T> { ... }
    fn error(&mut self, kind: ErrorKind) -> Error { ... }
    fn finish<T>(self, value: T) -> Result<T> { ... }
    fn is_finished(&self) -> bool { ... }
    fn offset(&self) -> Length { ... }
    fn peek_tag(&self) -> Result<Tag> { ... }
    fn read_byte(&mut self) -> Result<u8> { ... }
    fn read_into<'o>(&mut self, buf: &'o mut [u8]) -> Result<&'o [u8]> { ... }
    fn read_nested<'n, T, F>(&'n mut self, len: Length, f: F) -> Result<T>
       where F: FnOnce(&mut NestedReader<'n, Self>) -> Result<T> { ... }
    fn read_vec(&mut self, len: Length) -> Result<Vec<u8>> { ... }
    fn remaining_len(&self) -> Length { ... }
    fn sequence<'n, F, T>(&'n mut self, f: F) -> Result<T>
       where F: FnOnce(&mut NestedReader<'n, Self>) -> Result<T> { ... }
    fn tlv_bytes(&mut self) -> Result<&'r [u8]> { ... }
}

Reader trait which reads DER-encoded input.

Required Methods

fn input_len(&self) -> Length

Get the length of the input.

fn peek_byte(&self) -> Option<u8>

Peek at the next byte of input without modifying the cursor.

fn peek_header(&self) -> Result<Header>

Peek forward in the input data, attempting to decode a Header from the data at the current position in the decoder.

Does not modify the decoder’s state.

fn position(&self) -> Length

Get the position within the buffer.

fn read_slice(&mut self, len: Length) -> Result<&'r [u8]>

Attempt to read data borrowed directly from the input as a slice, updating the internal cursor position.

Returns

• Ok(slice) on success
• Err(ErrorKind::Incomplete) if there is not enough data
• Err(ErrorKind::Reader) if the reader can’t borrow from the input

Provided Methods

fn context_specific<T>( &mut self, tag_number: TagNumber, tag_mode: TagMode, ) -> Result<Option<T>>

where T: DecodeValue<'r> + FixedTag,

Attempt to decode an ASN.1 CONTEXT-SPECIFIC field with the provided TagNumber.

fn decode<T: Decode<'r>>(&mut self) -> Result<T>

Decode a value which impls the Decode trait.

fn error(&mut self, kind: ErrorKind) -> Error

Return an error with the given ErrorKind, annotating it with context about where the error occurred.

fn finish<T>(self, value: T) -> Result<T>

Finish decoding, returning the given value if there is no remaining data, or an error otherwise

fn is_finished(&self) -> bool

Have we read all of the input data?

fn offset(&self) -> Length

Offset within the original input stream.

This is used for error reporting, and doesn’t need to be overridden by any reader implementations (except for the built-in NestedReader, which consumes nested input messages)

fn peek_tag(&self) -> Result<Tag>

Peek at the next byte in the decoder and attempt to decode it as a Tag value.

Does not modify the decoder’s state.

fn read_byte(&mut self) -> Result<u8>

Read a single byte.

fn read_into<'o>(&mut self, buf: &'o mut [u8]) -> Result<&'o [u8]>

Attempt to read input data, writing it into the provided buffer, and returning a slice on success.

Returns

• Ok(slice) if there is sufficient data
• Err(ErrorKind::Incomplete) if there is not enough data

fn read_nested<'n, T, F>(&'n mut self, len: Length, f: F) -> Result<T>

where F: FnOnce(&mut NestedReader<'n, Self>) -> Result<T>,

Read nested data of the given length.

fn read_vec(&mut self, len: Length) -> Result<Vec<u8>>

Read a byte vector of the given length.

fn remaining_len(&self) -> Length

Get the number of bytes still remaining in the buffer.

fn sequence<'n, F, T>(&'n mut self, f: F) -> Result<T>

where F: FnOnce(&mut NestedReader<'n, Self>) -> Result<T>,

Read an ASN.1 SEQUENCE, creating a nested Reader for the body and calling the provided closure with it.

fn tlv_bytes(&mut self) -> Result<&'r [u8]>

Obtain a slice of bytes contain a complete TLV production suitable for parsing later.

Object Safety

This trait is not object safe.

Implementors

impl<'a> Reader<'a> for SliceReader<'a>

impl<'i> Reader<'i> for PemReader<'i>