Struct bsn1::Id

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pub struct Id { /* private fields */ }

Expand description

Id owns IdRef and represents ‘Identifier’.

The structure of Id is similar to that of Vec<u8>.

The user can access the inner IdRef via the Deref and DerefMut implementations.

Implementations§

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impl Id

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pub fn new(class: ClassTag, pc: PCTag, number: TagNumber) -> Self

Creates a new instance from class , pc , and number.

§Warnings

ASN.1 reserves some universal identifier numbers and they should not be used, however, this function ignores the rule. For example, number 15 (0x0f) is reserved for now, but this function accepts such a number without any error.

§Examples

use bsn1::{Id, IdRef};

let idref = IdRef::integer();
let id = Id::new(idref.class(), idref.pc(), idref.number().unwrap());
assert_eq!(idref, &id);

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pub fn parse<R>(readable: &mut R) -> Result<Self, Error>
where R: ?Sized + Read,

Parses readable starting with identifier and tries to build a new instance.

This function ignores extra octet(s) at the end if any.

§Performance

This function is not so efficient compared with IdRef::parse. If you have a slice of serialized bytes, use IdRef::parse and then call ToOwned::to_owned instead.

§Warnings

ASN.1 reserves some universal identifier numbers and they should not be used, however, this function ignores the rule. For example, number 15 (0x0f) is reserved for now, but this functions returns Ok.

§Examples

use bsn1::{Id, IdRef};

// Serialize an 'identifier' representing 'utf8-string'
let id = IdRef::utf8_string();
let mut serialized = Vec::from(id.as_ref());

// Deserialize it.
let deserialized = Id::parse(&mut &serialized[..]).unwrap();
assert_eq!(id, &deserialized);

// Extra octets at the end does not affect the result.
serialized.push(0);
serialized.push(1);
let deserialized = Id::parse(&mut &serialized[..]).unwrap();
assert_eq!(id, &deserialized);

// We can use `IdRef::parse` instead. It is more efficient.
let deserialized: Id = IdRef::parse(&mut &serialized[..]).map(ToOwned::to_owned).unwrap();
assert_eq!(id, &deserialized);

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pub unsafe fn from_bytes_unchecked(bytes: &[u8]) -> Self

Provides a reference from bytes without any check. bytes must not include any extra octet.

If it is not sure whether bytes is valid octets as an identifer, use parse instead.

§Safety

The behaviour is undefined if the format of bytes is bad as ‘identifier octets’.

§Examples

use bsn1::{Id, IdRef};

let id = IdRef::eoc();
let serialized = id.as_ref();
let deserialized = unsafe { Id::from_bytes_unchecked(serialized) };
assert_eq!(deserialized, id);

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pub fn set_number(&mut self, num: TagNumber)

Update the number of self.

§Examples

use bsn1::{ClassTag, Id, PCTag};

let mut id = Id::new(ClassTag::Private, PCTag::Primitive, 13_u8.into());
assert_eq!(id.number().unwrap(), 13_u8.into());

id.set_number(34_u8.into());
assert_eq!(id.number().unwrap(), 34_u8.into());

Methods from Deref<Target = IdRef>§

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pub fn len(&self) -> usize

Returns the byte count of the inner bytes.

§Examples

use bsn1::IdRef;

// Id of Universal Integer is [0x02]. It is 1 byte long.
let id = IdRef::integer();
assert_eq!(id.len(), 1);

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pub fn class(&self) -> ClassTag

Returns the ClassTag of self.

§Examples

use bsn1::{ClassTag, IdRef};

// 'EOC' is defined as Universal class.
let eoc = IdRef::eoc();
assert_eq!(ClassTag::Universal, eoc.class());

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pub fn is_universal(&self) -> bool

Returns true if self is ‘Universal class’, or false.

§Examples

use bsn1::{ClassTag, Id, PCTag};

// 'Id' implements 'Deref<Target = IdRef>'.
let id = Id::new(ClassTag::Universal, PCTag::Primitive, 0_u8.into());
assert_eq!(true, id.is_universal());

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pub fn is_application(&self) -> bool

Returns true if self is ‘Application class’, or false.

§Examples

use bsn1::{ClassTag, Id, PCTag};

// 'Id' implements 'Deref<Target = IdRef>'.
let id = Id::new(ClassTag::Application, PCTag::Primitive, 0_u8.into());
assert_eq!(true, id.is_application());

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pub fn is_context_specific(&self) -> bool

Returns true if self is ‘Context Specific class’, or false.

§Examples

use bsn1::{ClassTag, Id, PCTag};

// 'Id' implements 'Deref<Target = IdRef>'.
let id = Id::new(ClassTag::ContextSpecific, PCTag::Primitive, 0_u8.into());
assert_eq!(true, id.is_context_specific());

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pub fn is_private(&self) -> bool

Returns true if self is ‘Private class’, or false.

§Examples

use bsn1::{ClassTag, Id, PCTag};

// 'Id' implements 'Deref<Target = IdRef>'.
let id = Id::new(ClassTag::Private, PCTag::Primitive, 0_u8.into());
assert_eq!(true, id.is_private());

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pub fn pc(&self) -> PCTag

Returns the Primitive/Constructed flag of self.

§Examples

use bsn1::{ClassTag, Id, PCTag};

// 'Id' implements 'Deref<Target = IdRef>'.
let id = Id::new(ClassTag::Universal, PCTag::Primitive, 0_u8.into());
assert_eq!(PCTag::Primitive, id.pc());

let id = Id::new(ClassTag::Application, PCTag::Constructed, 1_u8.into());
assert_eq!(PCTag::Constructed, id.pc());

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pub fn is_primitive(&self) -> bool

Returns true if self is flagged as ‘Primitive’, or false.

§Examples

use bsn1::{ClassTag, Id, PCTag};

// 'Id' implements 'Deref<Target = IdRef>'.
let id = Id::new(ClassTag::Universal, PCTag::Primitive, 0_u8.into());
assert_eq!(true, id.is_primitive());

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pub fn is_constructed(&self) -> bool

Returns true if self is flagged as ‘Constructed’, or false.

§Examples

use bsn1::{ClassTag, Id, PCTag};

// 'Id' implements 'Deref<Target = IdRef>'.
let id = Id::new(ClassTag::Universal, PCTag::Constructed, 0_u8.into());
assert_eq!(true, id.is_constructed());

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pub fn number(&self) -> Result<TagNumber, Error>

Returns the number of self unless overflow.

§Examples

use bsn1::{ClassTag, Id, IdRef, PCTag};
use std::ops::Deref;

let id = Id::new(ClassTag::Application, PCTag::Primitive, 49_u8.into());
let idref: &IdRef = id.deref();
assert_eq!(49, idref.number().unwrap().get());

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pub fn set_class(&mut self, cls: ClassTag)

Update the class of self.

§Examples

use bsn1::{ClassTag, IdRef};

// Creates a '&mut IdRef' representing 'Universal Integer'.
let mut bytes = Vec::from(IdRef::integer().as_ref());
let idref = IdRef::parse_mut(&mut &mut bytes[..]).unwrap();

assert_eq!(ClassTag::Universal, idref.class());

idref.set_class(ClassTag::Application);
assert_eq!(ClassTag::Application, idref.class());

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pub fn set_pc(&mut self, pc: PCTag)

Update the Primitive/Constructed flag of self.

§Examples

use bsn1::{PCTag, IdRef};

let id = IdRef::integer();
let mut serialized = Vec::from(id.as_ref());
let deserialized = IdRef::parse_mut(&mut &mut serialized[..]).unwrap();

// 'Integer' is primitive.
assert_eq!(PCTag::Primitive, deserialized.pc());

// Force to change into constructed.
deserialized.set_pc(PCTag::Constructed);
assert_eq!(PCTag::Constructed, deserialized.pc());