hickory_proto/rr/
serial_number.rs

1//! Number type to support Serial Number Arithmetics
2
3use core::{cmp::Ordering, ops::Add};
4
5/// Wrapper type to support Serial Number Arithmetics as defined
6/// in RFC 1982. The signaure fields (expireation, inception) defined in RFC 4034, section 3.1.5
7/// are serial numbers.
8#[derive(Debug, Copy, Clone, PartialEq)]
9pub struct SerialNumber(pub(crate) u32);
10
11impl SerialNumber {
12    /// Returns internal value
13    pub fn get(&self) -> u32 {
14        self.0
15    }
16}
17
18/// Serial Number Addition, see RFC 1982, section 3.1
19///
20/// The result is a wrapping add.
21impl Add for SerialNumber {
22    type Output = Self;
23
24    fn add(self, rhs: Self) -> Self::Output {
25        Self(self.0.wrapping_add(rhs.0))
26    }
27}
28
29/// Serial Number Comparison, see RFC 1982, section 3.2
30impl PartialOrd for SerialNumber {
31    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
32        const SERIAL_BITS_HALF: u32 = 1 << (u32::BITS - 1);
33
34        let i1 = self.0;
35        let i2 = other.0;
36
37        if i1 == i2 {
38            Some(Ordering::Equal)
39        } else if (i1 < i2 && (i2 - i1) < SERIAL_BITS_HALF)
40            || (i1 > i2 && (i1 - i2) > SERIAL_BITS_HALF)
41        {
42            Some(Ordering::Less)
43        } else if (i1 < i2 && (i2 - i1) > SERIAL_BITS_HALF)
44            || (i1 > i2 && (i1 - i2) < SERIAL_BITS_HALF)
45        {
46            Some(Ordering::Greater)
47        } else {
48            None
49        }
50    }
51}
hickory_proto/rr/serial_number.rs

hickory_proto/rr/
serial_number.rs
