make cli sub-crate

cli/src/main.rs

@@ -0,0 +1,42 @@
+use clap::Parser;
+use clap_num::maybe_hex;
+use std::fs::File;
+use std::io::{Read, Write, stdin, stdout};
+use chacha::do_chacha;
+
+#[derive(Parser, Debug)]
+#[command(version, about, long_about = None)]
+struct Args {
+    /// Where the key is stored
+    #[arg(short, long)]
+    key_file: String,
+
+    /// The amount of chacha rounds to do
+    #[arg(short, long, default_value = "20")]
+    rounds: usize,
+
+    /// The nonce in the initial key value
+    #[arg(short, long, default_value = "0", value_parser=maybe_hex::<u64>)]
+    nonce: u128,
+}
+
+fn main() {
+    let args = Args::parse();
+
+    let stdin = stdin();
+
+    let mut f = File::open(args.key_file).expect("failed to open key file");
+    let key_bytes = &mut [0u8; 32];
+    f.read_exact(key_bytes).expect("couldn't read key file");
+
+    let mut input = Vec::new();
+    let mut inp = stdin.lock();
+    inp.read_to_end(&mut input)
+        .expect("failed to read from stdin");
+
+    let bytes = do_chacha(input.as_slice(), key_bytes, [(args.nonce >> 64& 0xFFFFFFFF) as u32, (args.nonce >> 32 & 0xFFFFFFFF) as u32, args.nonce as u32], 0, args.rounds);
+
+    let stdout = stdout();
+    let mut out = stdout.lock();
+    out.write_all(bytes.as_slice()).unwrap();
+}