kona_protocol/batch/
prefix.rs

1//! Raw Span Batch Prefix
2
3use crate::{SpanBatchError, SpanDecodingError};
4use alloy_primitives::{FixedBytes, bytes};
5
6/// Span Batch Prefix
7#[derive(Debug, Clone, Default, PartialEq, Eq)]
8pub struct SpanBatchPrefix {
9    /// Relative timestamp of the first block
10    pub rel_timestamp: u64,
11    /// L1 origin number
12    pub l1_origin_num: u64,
13    /// First 20 bytes of the first block's parent hash
14    pub parent_check: FixedBytes<20>,
15    /// First 20 bytes of the last block's L1 origin hash
16    pub l1_origin_check: FixedBytes<20>,
17}
18
19impl SpanBatchPrefix {
20    /// Decodes a [SpanBatchPrefix] from a reader.
21    pub fn decode_prefix(r: &mut &[u8]) -> Result<Self, SpanBatchError> {
22        let mut prefix = Self::default();
23        prefix.decode_rel_timestamp(r)?;
24        prefix.decode_l1_origin_num(r)?;
25        prefix.decode_parent_check(r)?;
26        prefix.decode_l1_origin_check(r)?;
27        Ok(prefix)
28    }
29
30    /// Decodes the relative timestamp from a reader.
31    pub fn decode_rel_timestamp(&mut self, r: &mut &[u8]) -> Result<(), SpanBatchError> {
32        let (rel_timestamp, remaining) = unsigned_varint::decode::u64(r)
33            .map_err(|_| SpanBatchError::Decoding(SpanDecodingError::RelativeTimestamp))?;
34        *r = remaining;
35        self.rel_timestamp = rel_timestamp;
36        Ok(())
37    }
38
39    /// Decodes the L1 origin number from a reader.
40    pub fn decode_l1_origin_num(&mut self, r: &mut &[u8]) -> Result<(), SpanBatchError> {
41        let (l1_origin_num, remaining) = unsigned_varint::decode::u64(r)
42            .map_err(|_| SpanBatchError::Decoding(SpanDecodingError::L1OriginNumber))?;
43        *r = remaining;
44        self.l1_origin_num = l1_origin_num;
45        Ok(())
46    }
47
48    /// Decodes the parent check from a reader.
49    pub fn decode_parent_check(&mut self, r: &mut &[u8]) -> Result<(), SpanBatchError> {
50        let (parent_check, remaining) = r.split_at(20);
51        let parent_check = FixedBytes::<20>::from_slice(parent_check);
52        *r = remaining;
53        self.parent_check = parent_check;
54        Ok(())
55    }
56
57    /// Decodes the L1 origin check from a reader.
58    pub fn decode_l1_origin_check(&mut self, r: &mut &[u8]) -> Result<(), SpanBatchError> {
59        let (l1_origin_check, remaining) = r.split_at(20);
60        let l1_origin_check = FixedBytes::<20>::from_slice(l1_origin_check);
61        *r = remaining;
62        self.l1_origin_check = l1_origin_check;
63        Ok(())
64    }
65
66    /// Encodes the [SpanBatchPrefix] into a writer.
67    pub fn encode_prefix(&self, w: &mut dyn bytes::BufMut) {
68        let mut u64_buf = [0u8; 10];
69        w.put_slice(unsigned_varint::encode::u64(self.rel_timestamp, &mut u64_buf));
70        w.put_slice(unsigned_varint::encode::u64(self.l1_origin_num, &mut u64_buf));
71        w.put_slice(self.parent_check.as_slice());
72        w.put_slice(self.l1_origin_check.as_slice());
73    }
74}
75
76#[cfg(test)]
77mod test {
78    use super::*;
79    use alloc::vec::Vec;
80    use alloy_primitives::address;
81
82    #[test]
83    fn test_span_batch_prefix_encoding_roundtrip() {
84        let expected = SpanBatchPrefix {
85            rel_timestamp: 0xFF,
86            l1_origin_num: 0xEE,
87            parent_check: address!("beef00000000000000000000000000000000beef").into(),
88            l1_origin_check: address!("babe00000000000000000000000000000000babe").into(),
89        };
90
91        let mut buf = Vec::new();
92        expected.encode_prefix(&mut buf);
93
94        assert_eq!(SpanBatchPrefix::decode_prefix(&mut buf.as_slice()).unwrap(), expected);
95    }
96}
kona_protocol/batch/prefix.rs

kona_protocol/batch/
prefix.rs
