1 //! Class of an ASN.1 tag. 2 3 use super::{TagNumber, CONSTRUCTED_FLAG}; 4 use core::fmt; 5 6 /// Class of an ASN.1 tag. 7 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)] 8 #[repr(u8)] 9 pub enum Class { 10 /// `UNIVERSAL`: built-in types whose meaning is the same in all 11 /// applications. 12 Universal = 0b00000000, 13 14 /// `APPLICATION`: types whose meaning is specific to an application, 15 /// 16 /// Types in two different applications may have the same 17 /// application-specific tag and different meanings. 18 Application = 0b01000000, 19 20 /// `CONTEXT-SPECIFIC`: types whose meaning is specific to a given 21 /// structured type. 22 /// 23 /// Context-specific tags are used to distinguish between component types 24 /// with the same underlying tag within the context of a given structured 25 /// type, and component types in two different structured types may have 26 /// the same tag and different meanings. 27 ContextSpecific = 0b10000000, 28 29 /// `PRIVATE`: types whose meaning is specific to a given enterprise. 30 Private = 0b11000000, 31 } 32 33 impl Class { 34 /// Compute the identifier octet for a tag number of this class. octet(self, number: TagNumber, constructed: bool) -> u835 pub(super) fn octet(self, number: TagNumber, constructed: bool) -> u8 { 36 self as u8 | number.value() | (constructed as u8 * CONSTRUCTED_FLAG) 37 } 38 } 39 40 impl fmt::Display for Class { fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result41 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { 42 f.write_str(match self { 43 Class::Universal => "UNIVERSAL", 44 Class::Application => "APPLICATION", 45 Class::ContextSpecific => "CONTEXT-SPECIFIC", 46 Class::Private => "PRIVATE", 47 }) 48 } 49 } 50