Support legacy LZMA format with `unpacked_size` 32bit long about lzma-rs HOT 10 OPEN

/// Read LZMA parameters from the LZMA stream header.
pub fn read_header<R>(input: &mut R, options: &Options) -> error::Result<LzmaParams>
where
    R: io::BufRead,
{
    // Properties
    let props = input.read_u8().map_err(error::Error::HeaderTooShort)?;

    let mut pb = props as u32;
    if pb == 0xFF {
        return Err(error::Error::InvalidLzmaProperties);
    }
    pb = pb % 9;

    let mut lp = (props / 9) as u32;
    if lp == 0xFF {
        return Err(error::Error::InvalidLzmaProperties);
    }
    lp = lp % 5;

    let mut lc = (props / (9 * 5)) as u32;
    if lc == 0xFF {
        return Err(error::Error::InvalidLzmaProperties);
    }
    lc = lc % 9;

    let properties = LzmaProperties { lc, lp, pb };

    // Dictionary size
    let mut dict_size = [0u8; 4];
    input
        .read_exact(&mut dict_size)
        .map_err(error::Error::HeaderTooShort)?;
    let dict_size = u32::from_le_bytes(dict_size) as usize;

    // Unpacked size
    let mut unpacked_size = [0u8; 8];
    input
        .read_exact(&mut unpacked_size[0..4])
        .map_err(error::Error::HeaderTooShort)?;
    let unpacked_size = u32::from_le_bytes(unpacked_size[0..4]) as usize;

    Ok(Self {
        properties,
        dict_size,
        unpacked_size,
    })
}

// Test reading LZMA params from a stream header with unpacked size
let mut input = Cursor::new(b"\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x64");
let options = Options::default();
let params = LzmaParams::read_header(&mut input, &options);
assert!(params.is_ok());
let params = params.unwrap();
assert_eq!(params.properties.lc, 0);
assert_eq!(params.properties.lp, 0);
assert_eq!(params.properties.pb, 1);
assert_eq!(params.dict_size, 1);
assert_eq!(params.unpacked_size, Some(100));

// Test reading LZMA params from a stream header with invalid properties
let mut input = Cursor::new(b"\xFF\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00");
let options = Options::default();
let params = LzmaParams::read_header(&mut input, &options);
assert!(params.is_err());

// Test reading LZMA params from a stream header with too few bytes
let mut input = Cursor::new(b"\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00");
let options = Options::default();
let params = LzmaParams::read_header(&mut input, &options);
assert!(params.is_err());