use std::path::Path;
use crate::gf256::GF256;

#[path="src/gf.rs"]
mod gf;
#[path="src/gf256.rs"]
mod gf256;

fn write_tbl(path: impl AsRef<Path>, name: &str, tbl: &[u8; 256]) {
    let mut res = format!("const INV_TBL: [{name}; {tbl_len}] = [\n", tbl_len=tbl.len());
    for v in tbl {
        res += &format!("\t{name}({v}),\n");
    }
    res += "];\n";

    std::fs::write(path, res).unwrap();
}

pub fn main() {
    let mut gf256_inv_tbl = [0;256];
    for i in 0..256 {
        gf256_inv_tbl[i] = u8::from(GF256::from(i as u8).minv_slow());
    }
    let mut out_file = std::path::PathBuf::from(std::env::var_os("OUT_DIR").unwrap());
    out_file.push("gf256_inv.rs");
    write_tbl(&out_file, "GF256", &gf256_inv_tbl);

    println!("cargo::rustc-cfg=rssss_have_codegen")
}