hickory_proto/rr/
serial_number.rs

1//! Number type to support Serial Number Arithmetics
2
3use core::{cmp::Ordering, ops::Add};
4
5#[cfg(feature = "serde")]
6use serde::{Deserialize, Serialize};
7
8/// Wrapper type to support Serial Number Arithmetics as defined
9/// in RFC 1982. The signaure fields (expireation, inception) defined in RFC 4034, section 3.1.5
10/// are serial numbers.
11#[cfg_attr(feature = "serde", derive(Deserialize, Serialize))]
12#[derive(Copy, Clone, Debug, Eq, Hash, PartialEq)]
13#[cfg_attr(feature = "serde", serde(transparent))]
14pub struct SerialNumber(pub(crate) u32);
15
16impl SerialNumber {
17    /// Create a new `SerialNumber` from the given value
18    pub fn new(value: u32) -> Self {
19        Self(value)
20    }
21
22    /// Returns internal value
23    pub fn get(&self) -> u32 {
24        self.0
25    }
26}
27
28impl From<u32> for SerialNumber {
29    fn from(value: u32) -> Self {
30        Self(value)
31    }
32}
33
34/// Serial Number Addition, see RFC 1982, section 3.1
35///
36/// The result is a wrapping add.
37impl Add for SerialNumber {
38    type Output = Self;
39
40    fn add(self, rhs: Self) -> Self::Output {
41        Self(self.0.wrapping_add(rhs.0))
42    }
43}
44
45/// Serial Number Comparison, see RFC 1982, section 3.2
46impl PartialOrd for SerialNumber {
47    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
48        const SERIAL_BITS_HALF: u32 = 1 << (u32::BITS - 1);
49
50        let i1 = self.0;
51        let i2 = other.0;
52
53        if i1 == i2 {
54            Some(Ordering::Equal)
55        } else if (i1 < i2 && (i2 - i1) < SERIAL_BITS_HALF)
56            || (i1 > i2 && (i1 - i2) > SERIAL_BITS_HALF)
57        {
58            Some(Ordering::Less)
59        } else if (i1 < i2 && (i2 - i1) > SERIAL_BITS_HALF)
60            || (i1 > i2 && (i1 - i2) < SERIAL_BITS_HALF)
61        {
62            Some(Ordering::Greater)
63        } else {
64            None
65        }
66    }
67}
hickory_proto/rr/serial_number.rs

hickory_proto/rr/
serial_number.rs
