der/asn1/bit_string/
allowed_len_bit_string.rs

1use core::ops::RangeInclusive;
2
3use crate::{Error, ErrorKind, Tag};
4
5/// Trait automatically derived on structs, by the `BitString` macro.
6/// Used for checking if binary data fits into defined struct.
7///
8/// ```
9/// /// Bit length of 2
10/// struct MyBitString {
11///     flag1: bool,
12///     flag2: bool,
13/// }
14/// ```
15///
16/// ```rust,ignore
17/// use der::BitString;
18///
19/// /// Bit length of 3..=4
20/// #[derive(BitString)]
21/// struct MyBitString {
22///     flag1: bool,
23///     flag2: bool,
24///     flag3: bool,
25///
26///     #[asn1(optional = "true")]
27///     flag4: bool,
28/// }
29/// ```
30pub trait AllowedLenBitString {
31    /// Implementer must specify how many bits are allowed
32    const ALLOWED_LEN_RANGE: RangeInclusive<u16>;
33
34    /// Check the bit length.
35    ///
36    /// # Errors
37    /// Returns an error if the bitstring is not in expected length range.
38    fn check_bit_len(bit_len: u16) -> Result<(), Error> {
39        let allowed_len_range = Self::ALLOWED_LEN_RANGE;
40
41        // forces allowed range to e.g. 3..=4
42        if !allowed_len_range.contains(&bit_len) {
43            Err(ErrorKind::Length {
44                tag: Tag::BitString,
45            }
46            .into())
47        } else {
48            Ok(())
49        }
50    }
51}
der/asn1/bit_string/allowed_len_bit_string.rs

der/asn1/bit_string/
allowed_len_bit_string.rs
