stream.rs

extern crate zstd;

use std::env;
use std::io::{self, Write};
use std::str::FromStr;

fn main() {
    match env::args().nth(1) {
        None => {
            writeln!(
                &mut io::stderr(),
                "Invalid option. Usage: `stream [-d|-1..-21]`"
            ).unwrap();
        }
        Some(ref option) if option == "-d" => decompress(),
        Some(ref option) => if option.starts_with('-') {
            let level = match i32::from_str(&option[1..]) {
                Ok(level) => level,
                Err(e) => panic!("Error parsing compression level: {}", e),
            };
            compress(level);
        } else {
            writeln!(
                &mut io::stderr(),
                "Invalid option. Usage: `stream [-d|-1..-21]`"
            ).unwrap();
        },
    }
}

fn compress(level: i32) {
    zstd::stream::copy_encode(io::stdin(), io::stdout(), level).unwrap();
}

fn decompress() {
    zstd::stream::copy_decode(io::stdin(), io::stdout()).unwrap();
}