zrip_core/block/
mod.rs

1#![forbid(unsafe_code)]
2
3use crate::error::DecompressError;
4
5#[derive(Debug, Clone, Copy, PartialEq, Eq)]
6pub enum BlockType {
7    Raw,
8    Rle,
9    Compressed,
10}
11
12#[derive(Debug, Clone, Copy)]
13pub struct BlockHeader {
14    pub last_block: bool,
15    pub block_type: BlockType,
16    pub block_size: u32,
17}
18
19pub fn parse_block_header(data: &[u8]) -> Result<BlockHeader, DecompressError> {
20    if data.len() < 3 {
21        return Err(DecompressError::InputExhausted);
22    }
23
24    let raw = u32::from_le_bytes([data[0], data[1], data[2], 0]);
25
26    let last_block = (raw & 1) != 0;
27    let block_type_bits = (raw >> 1) & 0x03;
28    let block_size = raw >> 3;
29
30    let block_type = match block_type_bits {
31        0 => BlockType::Raw,
32        1 => BlockType::Rle,
33        2 => BlockType::Compressed,
34        _ => return Err(DecompressError::BadBlockType),
35    };
36
37    Ok(BlockHeader {
38        last_block,
39        block_type,
40        block_size,
41    })
42}
43
44#[cfg(test)]
45mod tests {
46    use super::*;
47
48    #[test]
49    fn parse_raw_block() {
50        let data = [0x00, 0x00, 0x01];
51        let hdr = parse_block_header(&data).unwrap();
52        assert!(!hdr.last_block);
53        assert_eq!(hdr.block_type, BlockType::Raw);
54        assert_eq!(hdr.block_size, 0x0001_0000 >> 3);
55    }
56
57    #[test]
58    fn parse_last_compressed() {
59        let data = [0x05, 0x00, 0x00];
60        let hdr = parse_block_header(&data).unwrap();
61        assert!(hdr.last_block);
62        assert_eq!(hdr.block_type, BlockType::Compressed);
63        assert_eq!(hdr.block_size, 0);
64    }
65}
zrip_core/block/mod.rs

zrip_core/block/
mod.rs
