asn1_rs/
class.rs

1use core::convert::TryFrom;
2use core::fmt;
3
4#[derive(Debug, Copy, Clone, PartialEq, Eq)]
5pub struct BerClassFromIntError(pub(crate) ());
6
7/// BER Object class of tag
8#[derive(Debug, Copy, Clone, Eq, PartialEq)]
9#[repr(u8)]
10pub enum Class {
11    /// `Universal` class of tags (`0b00`)
12    Universal = 0b00,
13    /// `Application` class of tags (`0b01`)
14    Application = 0b01,
15    /// `Context-Specific` class of tags (`0b10`)
16    ContextSpecific = 0b10,
17    /// `Private` class of tags (`0b11`)
18    Private = 0b11,
19}
20
21impl Class {
22    /// `Universal` class of tags (`0b00`)
23    pub const UNIVERSAL: u8 = 0b00;
24    /// `Application` class of tags (`0b01`)
25    pub const APPLICATION: u8 = 0b01;
26    /// `Context-Specific` class of tags (`0b10`)
27    pub const CONTEXT_SPECIFIC: u8 = 0b10;
28    /// `Private` class of tags (`0b11`)
29    pub const PRIVATE: u8 = 0b11;
30
31    pub const fn assert_eq(&self, class: Class) -> Result<(), crate::error::Error> {
32        if *self as u8 == class as u8 {
33            Ok(())
34        } else {
35            Err(crate::error::Error::UnexpectedClass {
36                expected: Some(class),
37                actual: *self,
38            })
39        }
40    }
41}
42
43impl fmt::Display for Class {
44    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
45        let s = match self {
46            Class::Universal => "UNIVERSAL",
47            Class::Application => "APPLICATION",
48            Class::ContextSpecific => "CONTEXT-SPECIFIC",
49            Class::Private => "PRIVATE",
50        };
51        write!(f, "{}", s)
52    }
53}
54
55impl TryFrom<u8> for Class {
56    type Error = BerClassFromIntError;
57
58    #[inline]
59    fn try_from(value: u8) -> Result<Self, Self::Error> {
60        match value {
61            0b00 => Ok(Class::Universal),
62            0b01 => Ok(Class::Application),
63            0b10 => Ok(Class::ContextSpecific),
64            0b11 => Ok(Class::Private),
65            _ => Err(BerClassFromIntError(())),
66        }
67    }
68}
69
70#[cfg(test)]
71mod tests {
72    use super::*;
73
74    #[test]
75    fn methods_class() {
76        let c = Class::Universal;
77        assert!(c.assert_eq(Class::Universal).is_ok());
78        assert!(c.assert_eq(Class::Private).is_err());
79
80        assert_eq!(Class::Universal.to_string().as_str(), "UNIVERSAL");
81        assert_eq!(Class::Application.to_string().as_str(), "APPLICATION");
82        assert_eq!(
83            Class::ContextSpecific.to_string().as_str(),
84            "CONTEXT-SPECIFIC"
85        );
86        assert_eq!(Class::Private.to_string().as_str(), "PRIVATE");
87
88        assert!(Class::try_from(0b00).is_ok());
89        assert!(Class::try_from(0b01).is_ok());
90        assert!(Class::try_from(0b10).is_ok());
91        assert!(Class::try_from(0b11).is_ok());
92        assert!(Class::try_from(4).is_err());
93    }
94}
asn1_rs/class.rs

asn1_rs/
class.rs
