Macro der_parser::parse_der_optional

macro_rules! parse_der_optional {
    ($i:expr, $f:ident) => { ... };
}

Parse an optional DER element

Try to parse an optional DER element, and return it as a ContextSpecific item with tag 0. If the parsing failed, the ContextSpecific object has value None.

use der_parser::*;
use nom::{IResult,Err,ErrorKind};

let empty = &b""[..];
let bytes1 = [ 0x30, 0x0a,
               0x0a, 0x03, 0x00, 0x00, 0x01,
               0x02, 0x03, 0x01, 0x00, 0x01];
let bytes2 = [ 0x30, 0x05,
               0x02, 0x03, 0x01, 0x00, 0x01];
let expected1  = DerObject::from_obj(DerObjectContent::Sequence(vec![
    DerObject::from_obj(
        DerObjectContent::ContextSpecific(0,
            Some(Box::new(DerObject::from_obj(DerObjectContent::Enum(1)))))
    ),
    DerObject::from_int_slice(b"\x01\x00\x01"),
]));
let expected2  = DerObject::from_obj(DerObjectContent::Sequence(vec![
    DerObject::from_obj(
        DerObjectContent::ContextSpecific(0, None),
    ),
    DerObject::from_int_slice(b"\x01\x00\x01"),
]));

fn parse_optional_enum(i:&[u8]) -> IResult<&[u8],DerObject> {
    parse_der_optional!(i, parse_der_enum)
}
fn parser(i:&[u8]) -> IResult<&[u8],DerObject> {
    parse_der_sequence_defined!(i,
        parse_optional_enum,
        parse_der_integer
    )
};

assert_eq!(parser(&bytes1), IResult::Done(empty, expected1));
assert_eq!(parser(&bytes2), IResult::Done(empty, expected2));