solana_sdk/
shred_version.rs

1#![cfg(feature = "full")]
2
3use solana_sdk::{
4    hard_forks::HardForks,
5    hash::{extend_and_hash, Hash},
6};
7
8pub fn version_from_hash(hash: &Hash) -> u16 {
9    let hash = hash.as_ref();
10    let mut accum = [0u8; 2];
11    hash.chunks(2).for_each(|seed| {
12        accum
13            .iter_mut()
14            .zip(seed)
15            .for_each(|(accum, seed)| *accum ^= *seed)
16    });
17    // convert accum into a u16
18    // Because accum[0] is a u8, 8bit left shift of the u16 can never overflow
19    #[allow(clippy::integer_arithmetic)]
20    let version = ((accum[0] as u16) << 8) | accum[1] as u16;
21
22    // ensure version is never zero, to avoid looking like an uninitialized version
23    version.saturating_add(1)
24}
25
26pub fn compute_shred_version(genesis_hash: &Hash, hard_forks: Option<&HardForks>) -> u16 {
27    use byteorder::{ByteOrder, LittleEndian};
28
29    let mut hash = *genesis_hash;
30    if let Some(hard_forks) = hard_forks {
31        for (slot, count) in hard_forks.iter() {
32            let mut buf = [0u8; 16];
33            LittleEndian::write_u64(&mut buf[..8], *slot);
34            LittleEndian::write_u64(&mut buf[8..], *count as u64);
35            hash = extend_and_hash(&hash, &buf);
36        }
37    }
38
39    version_from_hash(&hash)
40}
41
42#[cfg(test)]
43mod tests {
44    use super::*;
45
46    #[test]
47    fn test_compute_shred_version() {
48        assert_eq!(compute_shred_version(&Hash::default(), None), 1);
49        let mut hard_forks = HardForks::default();
50        assert_eq!(
51            compute_shred_version(&Hash::default(), Some(&hard_forks)),
52            1
53        );
54        hard_forks.register(1);
55        assert_eq!(
56            compute_shred_version(&Hash::default(), Some(&hard_forks)),
57            55551
58        );
59        hard_forks.register(1);
60        assert_eq!(
61            compute_shred_version(&Hash::default(), Some(&hard_forks)),
62            46353
63        );
64    }
65}
solana_sdk/shred_version.rs

solana_sdk/
shred_version.rs
