锐捷 - SuConfig.dat解密Rust版

pub fn decode_config(file_path: &str) {
    let mut file_bytes = std::fs::read(file_path).unwrap();
    let mut dst = vec![0u8; 2048];
    decode_dat(&mut file_bytes, dst.as_mut_slice());

    let mut config = String::new();
    for i in 0..dst.len() {
        if dst[i] == 0 {
            break;
        }
        config.push(dst[i] as char);
    }
    info!("解密成功，原文如下：\n{}", config);
}

fn decode_dat(src: &mut [u8], dst: &mut [u8]) {
    let mut tmp = vec![0x20u8; 0x8000];
    for i in 0..src.len() {
        src[i] = 255 - src[i];
    }

    let mut m = 0;
    let mut n = 0;
    let mut d = 0;
    let mut si = 0;
    let mut di = 0;
    let mut s;

    s = src[si];
    si += 1;
    loop {
        if si >= src.len() {
            return;
        }
        for i in 0..8 {
            d = 1 << i;
            if (s & d) == 0 {
                d = src[si];
                si += 1;
                if si >= src.len() {
                    return;
                }
                tmp[(m << 7) ^ n] = d;
            } else {
                d = tmp[(m << 7) ^ n];
            }
            dst[di] = d;
            di += 1;
            if di >= dst.len() {
                return;
            }
            m = n;
            n = d as usize;
        }
        s = src[si];
        si += 1;
    }
}