Struct iso7816_tlv::simple::Tag

pub struct Tag(/* private fields */);

Tag for SIMPLE-TLV data as defined in [ISO7816-4].

The tag field consists of a single byte encoding a tag number from 1 to 254. The values ‘00’ and ‘FF’ are invalid for tag fields.

Tags can be generated using the TryFrom trait from u8 or hex str.

Example

use std::convert::TryFrom;
use iso7816_tlv::simple::Tag;

// get tag from u8 or &str
assert!(Tag::try_from("80").is_ok());
assert!(Tag::try_from(8u8).is_ok());
assert!(Tag::try_from(0x80).is_ok());
assert!(Tag::try_from(127).is_ok());

assert!(Tag::try_from("er").is_err());
assert!(Tag::try_from("00").is_err());
assert!(Tag::try_from("ff").is_err());

// get tag as u8
let tag = Tag::try_from("80")?;
let _tag_as_u8: u8 = tag.into();
let _tag_as_u8 = Into::<u8>::into(tag);

Implementations

impl Tag

pub const fn try_from_u8(v: u8) -> Result<Self, TlvError>

Tries to convert a u8 into a Tag. This is equivalent to the TryFrom impl for u8, except that this fn is const and can be used in some contexts that TryFrom cannot be used in, for example for defining constants:

use iso7816_tlv::simple::Tag;

const SOME_TAG_CONSTANT: Tag = match Tag::try_from_u8(0x42) {
    Ok(tag) => tag,
    Err(e) => panic!(),
};

Errors

This method returns Err(TlvError::InvalidInput) if v is not a legal tag (e.g., if v is 0x00 or 0xFF).

Trait Implementations

impl Clone for Tag

fn clone(&self) -> Tag

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Tag

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

Formats the value using the given formatter.

impl Into<u8> for Tag

fn into(self) -> u8

Converts this type into the (usually inferred) input type.

impl PartialEq for Tag

fn eq(&self, other: &Tag) -> 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<&str> for Tag

type Error = TlvError

The type returned in the event of a conversion error.

fn try_from(v: &str) -> Result<Self, TlvError>

Performs the conversion.

impl TryFrom<u8> for Tag

type Error = TlvError

The type returned in the event of a conversion error.

fn try_from(v: u8) -> Result<Self, TlvError>

Performs the conversion.

impl Copy for Tag

impl StructuralPartialEq for Tag