Struct TagPeeker

pub struct TagPeeker {
    pub next_tag: Tag,
}

Used to peek next tag by using Deserializer::deserialize_identifier.

Can be used to implement ASN.1 Choice.

Examples

use serde::de;
use picky_asn1::{
    wrapper::{IntegerAsn1, Utf8StringAsn1},
    tag::{Tag, TagPeeker},
};
use std::fmt;

pub enum MyChoice {
    Integer(u32),
    Utf8String(String),
}

impl<'de> de::Deserialize<'de> for MyChoice {
    fn deserialize<D>(deserializer: D) -> Result<Self, <D as de::Deserializer<'de>>::Error>
    where
        D: de::Deserializer<'de>,
    {
        struct Visitor;

        impl<'de> de::Visitor<'de> for Visitor {
            type Value = MyChoice;

            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                formatter.write_str("a valid MyChoice")
            }

            fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
            where
                A: de::SeqAccess<'de>,
            {
                match seq.next_element::<TagPeeker>()?.unwrap().next_tag {
                    Tag::INTEGER => {
                        let value = seq.next_element::<u32>()?.unwrap();
                        Ok(MyChoice::Integer(value))
                    }
                    Tag::UTF8_STRING => {
                        let value = seq.next_element::<String>()?.unwrap();
                        Ok(MyChoice::Utf8String(value))
                    }
                    _ => Err(de::Error::invalid_value(
                        de::Unexpected::Other(
                            "[MyChoice] unsupported or unknown choice value",
                        ),
                        &"a supported choice value",
                    ))
                }
            }
        }

        deserializer.deserialize_enum("MyChoice", &["Integer", "Utf8String"], Visitor)
    }
}

let buffer = b"\x0C\x06\xE8\x8B\x97\xE5\xAD\x97";
let my_choice: MyChoice = picky_asn1_der::from_bytes(buffer).unwrap();
match my_choice {
    MyChoice::Integer(_) => panic!("wrong variant"),
    MyChoice::Utf8String(string) => assert_eq!(string, "苗字"),
}

Fields

next_tag: Tag

Trait Implementations

impl Clone for TagPeeker

fn clone(&self) -> TagPeeker

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TagPeeker

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TagPeeker

fn deserialize<D>(deserializer: D) -> Result<TagPeeker, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for TagPeeker

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 Ord for TagPeeker

fn cmp(&self, other: &TagPeeker) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for TagPeeker

fn eq(&self, other: &TagPeeker) -> 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 TagPeeker

fn partial_cmp(&self, other: &TagPeeker) -> 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 Eq for TagPeeker

impl StructuralPartialEq for TagPeeker