zwergli/src/main.rs

use std::ffi::CStr;

fn main() {
    let gz = std::env::args().nth(1).unwrap();
    let gz = std::fs::read(gz).unwrap();

    assert_eq!(gz[0], 31, "ID");
    assert_eq!(gz[1], 139, "ID");
    assert_eq!(gz[2], 8, "compression method");

    let flg = gz[3];

    assert!(flg == 8 || flg == 0); // only FLG.FNAME

    let mut data_start = 10;

    if flg & 0b1000 != 0 {
        let fname = CStr::from_bytes_until_nul(&gz[10..]).unwrap();
        dbg!(fname);
        data_start += fname.count_bytes() + 1;
    }

    let blocks = &gz[(data_start)..];
    let blocks = &blocks[..(blocks.len() - 8)]; // crc32 and isize

    let mut out = Vec::new();

    zwergli::inflate(blocks, &mut out);

    dbg!(&out);
    dbg!(String::from_utf8(out)).ok();
}