coreutils/base64/base64.rs

#[crate_id(name="base64", vers="1.0.0", author="Jordy Dickinson")];

/*
 * This file is part of the uutils coreutils package.
 *
 * (c) Jordy Dickinson <jordy.dickinson@gmail.com>
 *
 * For the full copyright and license information, please view the LICENSE file
 * that was distributed with this source code.
 */

extern mod extra;

use std::char;
use std::io::{File, stdin, stdout};
use std::os;
use std::str;

use extra::getopts::groups::{
    getopts,
    optflag,
    optopt,
    usage
};
use extra::base64;
use extra::base64::{FromBase64, ToBase64};

fn main() {
    let args = ~os::args();
    let opts = ~[
        optflag("d", "decode", "decode data"),
        optflag("i", "ignore-garbage", "when decoding, ignore non-alphabetic characters"),
        optopt("w", "wrap",
            "wrap encoded lines after COLS character (default 76, 0 to disable wrapping)", "COLS"
        ),
        optflag("h", "help", "display this help text and exit"),
        optflag("V", "version", "output version information and exit")
    ];
    let matches = match getopts(args.tail(), opts) {
        Ok(m) => m,
        Err(e) => {
            error!("error: {:s}", e.to_err_msg());
            fail!()
        }
    };

    let progname = args[0].clone();
    let usage = usage("Base64 encode or decode FILE, or standard input, to standard output.", opts);
    let mode = if matches.opt_present("help") {
        Help
    } else if matches.opt_present("version") {
        Version
    } else if matches.opt_present("decode") {
        Decode
    } else {
        Encode
    };
    let ignore_garbage = matches.opt_present("ignore-garbage");
    let line_wrap = match matches.opt_str("wrap") {
        Some(s) => match from_str(s) {
            Some(s) => s,
            None => {
                error!("error: {:s}", "Argument to option 'wrap' improperly formatted.");
                fail!()
            }
        },
        None => 76
    };
    let mut input = if matches.free.is_empty() || matches.free[0] == ~"-" {
        ~stdin() as ~Reader
    } else {
        let path = Path::new(matches.free[0]);
        ~File::open(&path) as ~Reader
    };

    match mode {
        Decode  => decode(input, ignore_garbage),
        Encode  => encode(input, line_wrap),
        Help    => help(progname, usage),
        Version => version()
    }
}

fn decode(input: &mut Reader, ignore_garbage: bool) {
    let mut to_decode = str::from_utf8_owned(input.read_to_end());

    to_decode = to_decode.replace("\n", "");

    if ignore_garbage {
        let standard_chars =
            bytes!("ABCDEFGHIJKLMNOPQRSTUVWXYZ",
            "abcdefghijklmnopqrstuvwxyz",
            "0123456789+/").map(|b| char::from_u32(*b as u32).unwrap());

        to_decode = to_decode
            .trim_chars(&|c| !standard_chars.contains(&c))
            .to_owned();
    }

    match to_decode.from_base64() {
        Ok(bytes) => {
            let mut out = stdout();

            out.write(bytes);
            out.flush();
        }
        Err(s) => {
            error!("error: {:s}", s);
            fail!()
        }
    }
}

fn encode(input: &mut Reader, line_wrap: uint) {
    let b64_conf = base64::Config {
        char_set: base64::Standard,
        pad: true,
        line_length: match line_wrap {
            0 => None,
            _ => Some(line_wrap)
        }
    };
    let to_encode = input.read_to_end();
    let mut encoded = to_encode.to_base64(b64_conf);

    // To my knowledge, RFC 3548 does not specify which line endings to use. It
    // seems that rust's base64 algorithm uses CRLF as prescribed by RFC 2045.
    // However, since GNU base64 outputs only LF (presumably because that is
    // the standard UNIX line ending), we strip CRs from the output to maintain
    // compatibility.
    encoded = encoded.replace("\r", "");

    println(encoded);
}

fn help(progname: &str, usage: &str) {
    println!("Usage: {:s} [OPTION]... [FILE]", progname);
    println("");
    println(usage);

    let msg = ~"With no FILE, or when FILE is -, read standard input.\n\n\
        The data are encoded as described for the base64 alphabet in RFC \
        3548. When\ndecoding, the input may contain newlines in addition \
        to the bytes of the formal\nbase64 alphabet. Use --ignore-garbage \
        to attempt to recover from any other\nnon-alphabet bytes in the \
        encoded stream.";

    println(msg);
}

fn version() {
    println("base64 1.0.0");
}

enum Mode {
    Decode,
    Encode,
    Help,
    Version
}